Chapter 12-13 Review Questions

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1

1

Energy is needed to make muscles relax.

TRUE

extends fingers and hand

extensor digitorum

Arrange the following list of biochemical events in the correct sequence. 1. An action potential is conducted deep into the muscle fiber by the T tubule. 2. Calcium ions bind to troponin. 3. The membranes of the sarcoplasmic reticulum become more permeable to calcium ions. 4. Calcium ions diffuse into the sarcoplasm around the myofibril. 5. The troponin-tropomyosin complex moves exposing active sites. 1, 5, 2, 3, 4 1, 3, 4, 2, 5 1, 2, 3, 4, 5 1, 3, 2, 5, 4 1, 4, 3, 2, 5

1, 3, 4, 2, 5

The sequence of travel by an action potential through the heart is...

1. SA node 2. AV node 3. AV bundle 4. Bundle branches (left and right) 5. Purkinje fibers

An artery is defined as:

A) a vessel that carries blood away from the heart

Match what happens during maximum muscle contraction to the following areas of a sarcomere. 1. A band Width 2. I band 3. H zone A remains constant B Narrows C Disappears

A,B,C

Cardiac muscle depends almost entirely on aerobic respiration to make ATP. A) True B) False

A. TRUE

The chordae tendineae are connected to the walls of the ventricle via the papillary muscles. A) True B) False

A. TRUE

The primary neurotransmitter at the neuromuscular junction is

ACh

Diagram of the microcirculation

(see picture)

Types of capillaries:

- Discontinuous - Fenestrated - Continuous

The active sites to which cross-bridges attach are found on the A sarcoplasmic reticulum. B actin myofilaments. C Z disks. D T tubules. E myosin myofilaments.

B

Energy is released when...

ATP is broken down into ADP and phosphate

A muscle shortens forcefully.

Contractility

Tropomyosin shifts off of the moyosin-binding sites of the actin protein during the ______________ phase.

Contraction

The step in which the action potential depolarizes the T tubules is called ___________.

Coupling

Conductivity

Electrically stimulating a muscle, Action potentials in the center of the fiber radiating to the ends and Depolarization of a single muscle fiber causing Depolarization of adjacent muscle fibers.

The connective tissue that surrounds each muscle fiber is called the _____________.

Endomysium

Which connective tissue wrapping separates individual muscle fibers?

Endomysium.

The outermost layer of connective tissue surrounding a skeletal muscle is the

Epimysium

Fascicles are bundles of muscle fibers made up of all the following except ___________.

Epithelial Tissue

Which muscle group is composed of mainly slow-twitch (type I) fibers?

Erector spinae muscles of the back

capillary beds

Every muscle fiber is served by WHAT that surrounds muscle fibers. Extensive vascular network.

A muscle can stretch beyond its normal resting length and still contract.

Extensibility

A complete muscle contraction is called a muscle twitch. True or False?

False

Once a tunnel of bone is formed around a blood vessel, the bone building cells of the periosteum lay down bone in concentric circles that fill in the tunnel.

False

Re polarization of the cardiac muscle fiber is termed excitation

False

Receptors that bind the neurotransmitter at the postsynaptic cell membrane are voltage-gated. T/F

False

T/F? Acetylcholine is broken down into acetic acid and cholinesterase by choline.

False

T/F? In a contracting muscle the Z lines come closer together:

False

True or False: Central fatigue is due to an accumulation of extracellular fluid K+

False

True or False: Eccentric contraction is when the muscle shortens while contracting

False

The binding of ATP allows the muscle filaments to slide past one another (T/F)

False The binding of ADP + Phosphate

Order Largest to Smallest

Fascicle>Fibers>Myofibril>Sarcomere>Myofilament>F-actin>Tropomyosin>Troponin>Ca2+.

Perimysium covers

Fasciculi

For an isometric muscle fiber contraction...

For isotonic contractions, the shortening velocity of a muscle fiber is inversely proportional to the mass of the load.

During contraction, the actin myofilaments slide toward the

H Zone

extensibility

In order to contract, a muscle cell must also be extensible- able to stretch again between contractions. Most cells rupture if they are stretched even a little, but skeletal muscle fibers can stretch to as much as 3x their contracted length

overlap

In the fully contracted muscle, the ends of the actin myofilament ______

Atria depolarize from what side to what side?

Left side to Right side

Acetylcholine receptors function as ___________.

Ligand-gated ion channels

What event results in the pressure deflection called the dicrotic notch?

Momentary increase in aortic pressure that occurs when its semilunar valve snaps shut

How is the motor unit appear in a muscle?

Motor units are spread out a little bit in the muscle fiber.

When the pressure in the ventricles becomes lower than the pressure of the atria?

The atrioventricular valves open

What is responsible for a graded response?

The combination of motor units and the frequency of APs generated.

Look at your graph showing muscle shortening against weight. With the trend in mind, predict the amount of isotonic contraction with the weight of 300 grams.

The muscle would not shortening, because the isometric contraction could not overcome such a heavy weight.

myofilament

a contractile protein found in myofibrils

Elastic filaments contain titin which is?

a huge springy protein

sarcoplasmic reticulum of skeletal muscle fibers

a modification of the smooth endoplasmic reticulum, surrounds myofilaments and forms a meshwork around each myofibril at the junction of A and I bands, it forms a pair of dilated terminal cisternae which pass around the myofibrils regulates muscle contraction by sequestering calcium ions (leading to relaxation) of releasing calcium ions (leading to contraction)

aponeurosis

a sheet of ct. that may attach muscle to bone, fascia, or to other muscles.

myosin

a thick protein that contracts and relaxes the m. fibers

Two strands of actin and one strand of regulatory protein coiled together is _____

a thin filament

People with myasthenia gravis have a deficiency of

acetylcholine receptors

End-diastolic volume (EDV)

achieved in each ventricle (about 130 mL of blood)

Myofibrils are composed primarily of

actin and myosin

The sequence of electrical changes that occurs along the sarcolemma when a muscle fiber is stimulated is known as the ___________. action potential resting potential membrane repolarization membrane hyperpolarization motor end plate potential

action potential

Physical activity

affects heart rate

The muscle that causes an action is the

agonist

All or None Response

all action potentials are all or none the response of an excitable cell to stimulation. It either happens or it doesn't Individual muscle cells are all or none Muscle as a whole is a graded response.

Which of the following is true during the resting membrane potential? More positive charges outside the cell. More sodium outside the cell. More negative charges inside the cell. Less sodium inside the cell. all are true

all are true

in order for a muscle to contract properly, it requires

all of the above

Cardiac muscle

all of the above.

Functions of muscles include

all of the above.

Two factors that promote movement of blood through the heart

alternate contraction and relaxation of the myocardium and opening and closing of the heart valves

What is tension?

amount of contraction per fiber, number of muscle fibers contracting

The bond between the actin and myosin head is broken when...

an ATP molecule binds to the myosin head.

A stimulus either causes an action potential or it doesn't. This is called an all-or-none response. a graded response. a latent period response. a relative refractory response. arbitrary response.

an all-or-none response.

Graded response

an intermediate response not all or none ability to lift something smoothly regardless of weight.

may control ulnar abduction during forearm pronation

anconeous

most of the redirection will occur in the ________

arterioles

Which of the following valves keeps blood from backing up into the left ventricle? A) pulmonary valve B) bicuspid valve C) aortic valve D) tricuspid valve

c. aortic valve

"systole" and "diastole"

can refer to contraction and relaxation of either type of chamber, they usually refer to the action of the ventricles

heart rate equation

beats/minutes

effort

biceps brachil

troponin

binds Ca2+ and starts the contraction cycle

deep fascia

binds muscles to other muscles

In a muscle fiber a triad consists of a __________ and two adjacent terminal cisternae.

T-tubule

Voltage sensitive proteins respond to the action potential that spreads down the ______________.

T-tubule

During contraction, the myosin myofilaments shorten. T OR F

TRUE

In the ventricles, the action potential travels along the interventricular septum to the apex of the heart, where it then spreads superiorly along the ventricle walls. A) True B) False

TRUE

Relaxation occurs when Ca2+ is transported back into the sarcoplasmic reticulum.

TRUE

The sliding of the myofilaments past each other cause the sarcomere to shorten. T OR F

TRUE

The ventricles begin to fill during ventricular diastole. A) True B) False

TRUE

Unflexing of the myosin head requires ATP. True False

TRUE

When cross bridges form and the muscle fibers contract, the actin myofilament slides past the myosin myofilament. TRUE FALSE

TRUE

Calcium channels in the ______________ open and release calcium ions into the sarcoplasm.

Terminal Cisternae

The sac-like regions of the sarcoplasmic reticulum that contain calcium ions are called the Sarcolemma Triad Terminal cisternae Sarcoplasmic reticulum T tubules

Terminal cisternae

myofibrils

The sacroplasm is occupied mainly by long protein bundles called WHAT- not to be confused with myofibers, the muscle cells themselves.

Since muscle fibers are composed of a series of sarcomeres laid down next to one another, then what happens to the length of the sarcomeres when muscle fibers are stretched?

The sarcomeres get longer.

What is the purpose of the triad?

The triad allows for Ca2+ release when a muscle fiber is excited.

What makes the mucus of a snail so interesting as an area of study?

This fluid changes its properties when subjected to stress.

Rapid filling / Passive ventricular filling

This phase begins with the *pressure* in the *ventricles* is *less than* the pressure in the *atria* - Atria relaxed - Ventricles relaxed

Ejection

This phase occurs as the *semilunar valves open* - Atria relaxed - Ventricles contract

Atrial contraction / Active ventricular filling

This phase provides the ventricles with the final 20% of blood volume - Atria contracts - Ventricles relaxed

When the membrane potential reaches ____________ an action potential spreads across the sarcolemma due to the opening of ________________.

Threshold; Voltage-gated Na+ channels

The area between the presynaptic nerve cell and postsynaptic muscle cell is termed the synaptic cleft (T/F)

True

The calcium involved in muscle contraction ultimately comes from extra cellular fluid , true or false?

True

The thin filament consists of actin, troponin, and tropomyosin molecules.

True

True or False: One adaptation to endurance training is that the muscles increase the number of mitochondria

True

True or False: The lactate threshold is the % O2max where a significant rise in the concentration of lactate in the blood occurs

True

Unflexing of the myosin head requires ATP (T/F)

True

nflexing of the myosin head requires ATP.

True

myosin filaments

Type of myofilaments. Each is made of several hundred molecules of a protein called myosin. A myosin molecule is shaped like a golf club, with two chains intertwined to form a shaftlike tail and a double globular head projecting from it at an angle.

In a cardiac muscle cell , the membrane potential decreases rapidly ?

When the potassium gates open and potassium diffuses out of the cardiac muscle fiber.

Are both sets of valves closed during any part of the cycle?

Yes, momentarily after atrial systole and ventricular systole

glycogen

Muscle fiber also contains an abundance of WHAT, a starchlike carbohydrate that provides energy for the cell during heightened levels of exercise.

Endomysium covers

Muscle fibers

contractility

Muscle fibers are unique in their ability to shorten sustainability when stimulated. This enables them to pull on bones and other tissues and create movements of the body and its parts.

myoblasts

Muscle fibers have multiple flattened nuclei pressed against the inside of the sarcolemma. Their unusual multinuclear condition results from their embryonic development- several stem cells called WHAT fuse to produce each muscle fiber, with each myoblast contributing a nucleus to the mature fiber.

Suggest a reason why there are numerous mitochondria in the sarcoplasm. (3)

Muscles require much energy from ATP for contractions; This energy from ATP is released during the Krebs cycle and ETC in respiration; Both of these processes take place in the mitochondria

During embryonic development multiple stem cells called ___________ fuse together to form each muscle fiber.

Myoblasts

As actin and myosin filaments slide past each other during muscle contraction (what shortens; actin + myosin filaments)

Neither actin or myosin filaments shorten*** I think myosin filaments shorten, while actin filaments do not

The myosin head is bound to ___________ when it is in the low energy conformation, and it is bound to the thin filament.

No Nucleotide

Discontinuous capillaries

Relatively *large gaps* between cells found in *bone marrow, liver, and spleen* allow *passage of proteins*

Calcium Ions return to the sarcoplasmic reticulum, detaching the cross-bridges so the sarcomere can lengthen, during the ____________ phase.

Relaxation

Pacemaker Physiology

SA node does not have a stable resting membrane potential - Starts at −60 mV and drifts upward due to slow Na+ inflow - When it reaches threshold of −40 mV, voltage-gated fast Ca2+ and Na+ channels open • Faster depolarization occurs peaking at 0 mV - K+ channels then open and K+ leaves the cell • When SA node fires it sets off heartbeat - As the internal pacemaker, it typically fires every 0.8 seconds, setting the resting rate at 75 bpm

Excitation causes?

Opening of voltage sensitive membrane calcium channels on the t-tubules

During muscle contraction

The A band remains the same and the I band narrows.

During muscle contraction:

The A band remains the same and the I band narrows.

Responsiveness

Placing a muscle in a solution containing Ca and ATP.

PVC stands for

Premature Ventricular Contractions

pulse

Pulse: surge of pressure produced by heart beat that can be felt by palpating a superficial artery i. High in babies: 120bpm or more ii. Young adults: 64-80bpm, lower in males iii. Raises in the elderly

terminal cisternae

The SR periodically exhibits dilated end-sacs called WHAT, which cross the muscle fiber from side to the other.

Cross bridges are formed between

The actin filaments and myosin heads

hinge

shaking your head no

the term aponeurosis refers to what?

sheetlike indirect attachment to a skeletal element

Which of the following describes the mucus used by the RoboSnail?

silicon and clay

smooth muscle cells

single, fusiform, uninucleate; no striations

skeletal muscle fibers

single, very long, cylindrical, multinucleate cells with striations

broad two-part muscle that lies on the back of the neck between base of skull and upper thorax

splenius capitis, and cervicis

Regina began an exercise program six months ago, and the muscles of her upper limbs and lower limbs are more prominent. Exercise can lead to formation of new muscle by

stimulating skeletal muscle cells to release IL-6, which stimulates satellite cells to divide, producing more muscle cells.

The sarcoplasmic reticulum

stores calcium ions.

The sarcoplasmic reticulum stores calcium ions. shortens during muscle contraction. transmits nerve impulses to the myofibrils. connects adjacent sarcomeres. covers the muscle fiber.

stores calcium ions.

Arrangement of fibers in muscle in which fibers are combined into parallel fibers

striated

Fibers in cardiac muscle are ________

striated

cardiac muscle

striated, involuntary, found in the heart

skeletal muscle

striated, voluntary, and attached to the skeleton

a fusion of twitch contractions; the second and subsequent contractions occur before the preceding one can relax

summation

Creatine phosphate

supplies energy for the synthesis of ATP.

abducts arm; stabilizes shoulder joint

supraspinatus

the circulation of blood from *heart* to remaining *organs and tissues* is the...

systemic circulation

the highest pressure exerted on the arterial walls during the heart cycle is referred to as

systolic blood pressure

normal blood pressure

systolic less than 120 and diastolic less than 80

Pressure point in front of the ear

temporal

elevates and retracts mandible

temporalis

the prolonged contraction of a muscle caused by rapidly repeated stimuli

tetanus

When the *pressure* in the *ventricles* becomes *lower* *than* the pressure in the *atria*...

the *AV valves open*

Ventricular *systole* causes...

the *AV valves to close*, and then the *semilunar valves to open*

What happens during muscle contraction?

the A band remains the same and the I band narrows

During muscle contraction

the A band remains the same and the I band narrows.

I

the ____ band contain only actin

effort

the applied force

When the pressure in the ventricles becomes lower than the pressure in the atria, __________.

the atrioventricular valves open When the ventricles relax, the pressure inside the ventricles decreases and becomes less than that of the atria. The decrease in pressure helps to open the atrioventricular valves.

sarcolemma

the plasma membrane of a single muscle fiber

refractory period

the time when fiber cannot be stimulated until repolarization is complete

During contraction of a muscle, calcium ions bind to...

the troponin molecule

What structures do the calcium ions bind to when muscle contraction is initiated?

the troponin molecule

During contraction of a muscle, calcium ions bind to

the troponin molecule.

During contraction of a muscle, calcium ions bind to...

the troponin molecule.

What is a sarcomere?

the unit of organization of skeletal muscle

Which of the following is not true for ventricular systole?

the ventricles relax

H

the zone that disappears in a fully contracted muscle.

A muscle fiber will respond to a stimulus when that stimulus reaches the _____ level.

threshold

The semimembranosus muscle belongs to the group known as the "hamstrings."

true

QRS wave

ventricular muscle depolarization - positive deflection

the sides that delineate one sarcomere from another

z lines/discs

raises lateral corners of the mouth smiling muscle

zygomaticus major and minor

the PQRST waves are normally how long?

~.8 seconds

Hypotension

chronic low resting BP - Caused by blood loss, dehydration, anemia

myofibril

composed of actin and myosin filaments.

muscle myofibrils

contain myosin and actin myofilaments.

when an external tension moves a load, this is called the ______ phase.

contraction

sarcoplasm

cytoplasm of skeletal muscle fiber

maintaining posture

development of tension to prevent movement, as in keeping the vertebral column upright

When are the semilunar valves closed?

diastole of heart as a whole and during atria systole

H zone

disappears during muscle contraction

positive chronotropic agents

factors that raise the heart rate

antagonists

groups of muscles that produce oppositely directed movements

Z

in a contracting muscle, the ___ lines come closer tog.

toxins from disease could indicate

irregular beat

stress can cause

irregular heart rate

Treppe

is achieved during warm-up exercises. is an example of a graded response. may be due to an increase in the level of calcium ions around the myofibril. can contribute to improved muscle efficiency.

Cardiac muscle is under involuntary control. is under voluntary control.

is under involuntary control.

How does the presence of the GLUT-4 carrier protein in the sarcolemma affect muscle metabolism

it increases muscle metabolism by allowing the cellular uptake of glucose for ATP production

What happens to the I band during muscle contraction?

it shortens

What happens to the H band during muscle contraction?

it shortens and disappears

The deltoid is a muscle named according to ___________. its shape the direction of its fibers its location the number of its origins

its shape

fascicles

join tog. to form a muscle. a group of skeletal m. fibers is _

Anna had a pace maker implanted to

keep the heart rhythmn constant. This is necessary because the SA node is not functioning properly

elevates, abducts, retracts, and steadies the scapula; flexes neck to the same side when the scapula is fixed

levator scapulae

example first-class lever

lifting your head off your chest

diastolic pressure

low pressure on artery wall when ventricles relax between contractions

At this junction, the ________ _______ releases a type of chemical called a ________.

motor neuron; neurotransmitter

A motor neuron and all the muscle fibers it supplies is called a(n) ____________. axon terminal motor unit motor end plate synaptic cleft neuromuscular junction

motor unit

Each somatic motor neuron, together with all of the muscle fibers it innervates, is called a ____________.

motor unit

a motor neuron and the skeletal muscle fibers innervated by that motor neuron's axon terminal

motor unit

What is the main function of skeletal muscles? energy consumption pumping of blood through the body movement destruction of foreign chemicals

movement

Skeletal muscle contracts the heart. moves the skeletal system. controls the automatic movements in our bodies.

moves the skeletal system.

flexes and abducts thigh

pectineus

The latency period is the time:

period between stimulation and the shortening of the skeletal muscle.

The alternating contraction and relaxation of opposing layers of smooth muscle is referred to as ___________. isotonic contraction peristalsis automatic contraction isometric contraction

peristalsis

Repolarization occurs because

potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage-gated sodium ion channels begin to close.

cardionatrin

potent natriuretic and diuretic hormone

Ventricular ejection

pressure in ventricles exceeds arterial pressure, semilunar valves open, blood leaves ventricles, T wave occurs late in this phase 1. Stroke volume (SV): amount of blood ejected by ventricles 2. Ejection fraction: percentage of blood ejected from ventricle (what percentage of EDV was ejected?) usually about 54% 3. End-systolic volume (ESV): blood left behind that is not ejected (EDV-SV=ESV)

Describe the thick filament

primarily composed of the protein mysoin. Contains a tail region and globular head-looks like a golf club connected together by a hinge. Mammalian mysoin dimerizes through inter twining of their tails.

lactic acid

product of anaerobic glycolysis

depolarization and generation of action potential

production of an end plate potential at the motor end plate and consequent depolarization of adjacent areas

slow-oxidative

prolonged, long term action

subtracting the SBP from the DBP results in _________ which is directly proportional to the overall strength of one's pulse

pulse pressure

All of the following muscles are innervated by the sciatic nerve, EXCEPT the ___________. biceps femoris quadratus femoris semitendinosus semimembranosus

quadratus femoris

fast-oxidative

rapid, long term action

fast-glycolytic

rapid, short term action

Elasticity refers to the ability of a muscle fiber to ___________. recoil and resume its resting length after being stretched shorten forcibly when adequately stimulated receive and respond to a stimulus be stretched

recoil and resume its resting place after being stretched

As you are lifting a box someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must

recruit more muscle fibers

the successive activation of the same and additional motor units with increasing strength of voluntary muscle contraction

recruitment

Muscles with fibers that run parallel an imaginary line such as the long axis of the body are called ____________. lateralis rectus transversus medialis obliques

rectus

During abdominal surgery, the surgeon makes a cut through the muscle directly to the right of the linea alba. The muscle that is being cut is the ___________. splenius diaphragm scalenes digastric rectus abdominis

rectus abdominis

Which muscle flexes and rotates the lumbar region of the vertebral column? transversus abdominis internal oblique external oblique rectus scaliness

rectus abdominis

Pulmonary Circuit

right side of the heart, carries blood to lungs for gas exchange, carries oxygen POOR blood.

myofibril

rodlike contractile elements within a muscle fiber containing microfilaments

The region of the myofibril between two Z lines that is the contractile unit of a muscle cell is called a I band H zone A band sarcomere Z line

sarcomere

the contractile unit of a myofibril; repeating units, delimited by the z bands

sarcomere

Contractility

Creation of force, Pulling two bones close together and Actively resisting the separation of two bones.

myofibril

Cylindrical structures within muscle fiber. They are bundles of myofilaments (protein filaments). There are two kinds of myofilaments: myosin and actin filaments

A concentric contraction is described as A action potential frequency is high enough that no relaxation of muscle fibers occurs. B a muscle produces constant tension during contraction. C a muscle produces an increasing tension during contraction. D a muscle produces increasing tension as it shortens. E a muscle produces tension, but the length of the muscle is increasing.

D

A myofibril is the A cell membrane of a muscle fiber. B cytoplasm of muscle cells. C structural and functional unit of the skeletal muscle cell. D contractile thread that extends the length of the muscle fiber. E protein strand composed of actin.

D

A single motor neuron and the muscle fibers that it innervates is called a ___________. A neuronal unit B active unit C postsynaptic unit D motor unit

D

Arrange the following in the proper order in which they occur at the post-synaptic side of a neuromuscular junction. 1 Calcium ions enter presynaptic terminal and cause release of Acetylcholine. 2 An action potential arrives at the presynaptic terminal 3 Diffusion of acetylcholine across the synaptic cleft and binding of acetylcholine to acetylcholine receptors A 1, 2, 3 B 2, 1, 3 C 2, 3, 1 D 3, 2, 1 E 3, 1, 2

D

As a result of extreme muscular fatigue, muscles can become incapable of relaxing or contracting, which is called _____________. Similarly, several hours after death, ATP levels decline, causing muscle muscle rigidity, known as ____________. A rigor mortis, physiological contracture B stiffness, physiological contracture C psychological fatigue, rigor mortis D physiological contracture, rigor mortis

D

Channels that open or close in response to changes in the electrical charge or voltage across the plasma membrane are called A ligand-gated ion channels. B non-gated ion channels. C relegated ion channels. D voltage-gated ion channels. E obligated ion channels.

D

Curare blocks acetylcholine receptors at the motor end plate. This would result in A increased stimulation of the muscle. B more acetylcholinesterase production. C lack of calcium uptake by the muscle fiber. D inability of the muscle fiber to respond to nervous stimulation. E sustained contraction of the muscle.

D

Depolarization of the cell membrane occurs when there is a rapid influx (inflow) of A potassium ions. B chloride ions. C calcium ions. D sodium ions. E amino acids.

D

During unfused tetanus A a muscle fiber under continuous stimulation and contraction becomes unable to contract at all until it has rested. B muscle fiber stimulations are such that muscle fibers are able to contract and then completely relax before the next contraction. C the stimuli arrive at the muscle fiber so rapidly that there is no muscle relaxation between stimuli, but rather, a continuous contraction of the muscle fiber. D the stimuli arrive at the muscle fiber at such a rate that the muscle fiber is unable to completely relax between stimuli, and sequential contractions exhibit an equal contractive force that is greater than when the muscle fiber is allowed to rest completely. E a second stimulus arrives at the muscle before complete relaxation of the first contraction, causing the second contraction to have greater tension than the first one.

D

Hypertrophy means that there is a(n) ______________ in the size of the muscle fibers, and there is usually _________ muscle fibers. A decrease, an increased number of B increase, an increased number of C decrease, a decreased number of D increase, no change in the number of

D

Muscles exhibit the property of excitability. This means that the muscle A shortens its length. B recoils to its original resting length. C stretches beyond its normal length. D responds to stimulation by the nervous system. E excites itself.

D

Muscular dystrophy is characterized by A chronic muscle pain. B decreased size of muscle fibers. C spastic contractions of muscles. D replacement of muscle cells by connective tissue. E hypertrophy of muscle tissue.

D

The elevated oxygen consumption relative to activity level after exercise has ended is called A oxygen deficit. B oxygen debt. C oxygen repayment. D recovery oxygen consumption. E anaerobic recovery.

D

Troponin A has two subunits. B is part of the myosin myofilament. C is a long, flexible protein. D has a calcium-binding site. E binds to ATP

D

Which of the following changes have the potential to dramatically affect the potential difference across the plasma membrane? A increased permeability of the membrane to sodium ions B increased intracellular concentration of potassium ions C any change in the rate at which the sodium-potassium pump works D increased permeability of the membrane to sodium ions and increased intracellular concentration of potassium ions E increased permeability of the membrane to sodium ions, increased intracellular concentration of potassium ions and any change in the rate at which the sodium-potassium pump works

D

Which of the following is NOT a function of skeletal muscle? A body movement B maintenance of posture c respiration D constriction of organs E production of heat

D

Which of the following is NOT an age related change in skeletal muscle? A loss of muscle strength B loss of synapse surface area C loss of fast-twitch fibers D decreased recovery time E decrease in motor units

D

Which of the following is mismatched? A I band - contains only actin B M line - middle of the H zone C Z disk - structure between adjacent sarcomeres D myosin myofilaments - thin myofilaments E actin myofilaments - thin myofilaments

D

Which of the following is the correct sequence of smooth muscle contraction? A) An increase in cytosolic calcium binds to the troponin complex, which binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin cross-bridges, which bind to actin filaments, resulting in contraction. B) An increase in cytosolic calcium binds to calmodulin in cytosol, which binds with myosin cross-bridges, resulting in contraction. An increase in cytosolic calcium binds to calmodulin in the cytosol, which moves tropomyosin from blocking the active sites on the actin filament, which binds with myosin cross-bridges, resulting in contraction. C) An increase in cytosolic calcium binds to troponin, which moves tropomyosin from blocking the active sites on the actin filament, which binds with myosin cross-bridges, resulting in contraction. D) An increase in cytosolic calcium binds to calmodulin in the cytosol. This complex binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin cross-bridges, which bind to the actin filaments' active sites, resulting in contraction.

D) An increase in cytosolic calcium binds to calmodulin in the cytosol. This complex binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin cross-bridges, which bind to the actin filaments' active sites, resulting in contraction.

The ____________ collects blood from all other veins draining the myocardium and returns this blood to the right atrium. A) great cardiac vein B) left circumflex artery C) posterior cardiac vein D) coronary sinus E) middle cardiac vein

D) coronary sinus

All of the following are cardiac stimulants except: A) epinephrine B) caffeine, nicotine, and chocolate C) thyroid hormone D) potassium and calcium ions

D) potassium and calcium ions

Which of the following is not true for ventricular systole? A) the ventricles contract. B) the atrioventricular valves close. C) the semilunar valves open. D) the ventricles relax. E) blood flows through the aorta and the pulmonary trunk.

D) the ventricles relax.

What is Depolarization?

DECREASE in the negative Resting Membrane Potential ( the VOLTAGE that exists across the plasma membrane ).

What happens to a muscle when it is significantly stretched both in vitro and invovo beyond the normal length?

Damage occurs to the structure of the muscle and the muscle may never again be capable of the maximum number of cross bridges. This is a typical hyperextension injuries to athletes.

(Refer to exam q) The diagram shows the banding pattern observed in part of a relaxed muscle fibril. Describe what causes the different bands seen in the muscle fibril. (2)

Darker band has both types of filament; Light band has only actin filaments

Phase 0 - Action Potential in Cardiac muscle cells

Depolarization - Na+ flows in and causes inside of the cell to become positive for short period of time

Movement of sodium ions into the muscle cell at the neuromuscular junction causes

Depolarization of the muscle cell membrane.

In a fully contracted sarcomere, the H zone

Disappears.

What is effective refractory period?

During phase 0, 1, 2, and part of 3, the cell is refractory to the initiation of new action potentials (allows time for each action potential to complete and re-fill. Prevents sustained contractions

Isovolumetric relaxation

During this phase, the *semilunar valves close* and produce the second heart sound - Atria relaxed - Ventricles relaxed - Semilunar valves closed (produces second heat sound "Dub")

Isovolumetric contraction

During this phase, the *ventricles* are *neither filling* with blood *nor ejecting* blood. AV valves closed shut - Atria is relaxed - Ventricles contract - AV valves closed (Tricuspid and Mitral valves) (produces first heat sound "Lub")

As actin and myosin filaments slide past each other during muscle contraction, A actin filaments shorten, while myosin filaments do not. B myosin filaments shorten, while actin filaments do not. C either actin or myosin filaments shorten, but not both at the same time. D both actin and myosin filaments shorten. E neither actin nor myosin filaments shorten.

E

Cross bridges form between... A troponin and tropomyosin. B calcium and sodium. C the sarcolemma and the sarcoplasmic reticulum. D the T-tubules and the sarcolemma. E the actin filaments and the myosin heads.

E

During twitch summation (a.k.a. temporal or wave summation) A a muscle fiber under continuous stimulation and contraction becomes unable to contract at all until it has rested. b muscle fiber stimulations are such that muscle fibers are able to contract and then completely relax before the next contraction. c the stimuli arrive at the muscle fiber so rapidly that there is no muscle relaxation between stimuli, but rather, a continuous contraction of the muscle fiber. d the stimuli arrive at the muscle fiber at such a rate that the muscle fiber is unable to completely relax between stimuli, and sequential contractions exhibit an equal contractive force that is greater than when the muscle fiber is allowed to rest completely. e a second stimulus arrives at the muscle before complete relaxation of the first contraction, causing the second contraction to have greater tension than the first one.

E

Which of the following is NOT a function of the muscular system? A Maintenance of posture B Constriction of organs and vessels C Respiration D Production of body heat E Immune system support F Production of body heat

E

Unlike skeletal muscles, cardiac muscle has this feature: A) larger cisternae B) smaller T tubules C) several nuclei D) long, slender, unbranched cells E) calcium ions can come from ECF

E) calcium ions can come from ECF

electrocardiogram

ECG/EKG: electrodes attached to ankles, wrists and 6 locations on chest. It's a composite recording of all action potentials produced by nodal and myocardial cells Electrocardiogram (ECG or EKG) - Composite of all action potentials of nodal and myocardial cells detected, amplified and recorded by electrodes on arms, legs, and chest

Which of the following is the connective tissue layer that surrounds the internal surface of each chamber of the heart? A) pericardium B) myocardium C) endocardium D) epicardium

ENDOCARDIUM

Which of the following is the connective tissue layer that covers the external surface of the heart? A) pericardium B) myocardium C) endocardium D) epicardium

EPICARDIUM (D)

Z disk

Each light I band is bisected by a dark narrow WHAT which provides anchorage for the thin filaments and elastic filaments. (A protein disc to which thin filaments and elastic filaments are anchored at each end of a sarcomere; appears as a narrow dark line in the middle of the I band)

skeletal muscle structure

Each muscle is an organ composed of muscle cells (fibers), connective tissue, blood vessels, nerves

sarcomere

Each segment of a myofilament from one Z disc to the next is called a WHAT, the functional contractile unit of the muscle fiber. About 10,000 sacromeres per myofibril each about 2 um long (The distance from one Z disc to the next; the contractile unit of a muscle fiber)

troponin

Each tropomyosin molecule has a smaller calcium-binding protein called WHAT bound to it. It is composed of 3 subunits: Tn-A: binds to actin, Tn-T: binds to tropomyosin, Tn-C: binds to calcium ions

titin filaments

Elastic chains of amino acids; keep thick and thin filaments in proper alignment. This helps to stabilize the thick filament, center it between the thin filaments, and prevent overstretching.

A muscle recoils to its original resting length after having been stretched.

Elasticity

(Refer to exam q) The table shows some properties of slow and fast muscle fibres. Endurance athletes, such as marathon runners, nearly always have a high proportion of slow muscle fibres in their muscles. Explain the benefit of this. (6)

Endurance athletes exercise for long periods of time; Respire aerobically; Slow fibres adapted to aerobic respiration; As they have many mitochondria; Which is the site of Kreb's cycle; Producing large amount of ATP

A muscle responds to a stimulus.

Excitability

Which of the following is the correct sequence of steps involved in a muscle contraction?

Excitation, Coupling, Contraction, and Relaxation

Exercise and Cardiac Output

Exercise makes the heart work harder and increases cardiac output • Proprioceptors signal cardiac center - At beginning of exercise, signals from joints and muscles reach the cardiac center of brain - Sympathetic output from cardiac center increases cardiac output • Increased muscular activity increases venous return - Increases preload and ultimately cardiac output • Increases in heart rate and stroke volume cause an increase in cardiac output • Exercise produces ventricular hypertrophy - Increased stroke volume allows heart to beat more slowly at rest - Athletes with increased cardiac reserve can tolerate more exertion than a sedentary person

A complete muscle contraction is called a muscle twitch.

FALSE

A short rest period after a muscle fiber experiences fatigue will allow that muscle fiber to contract again equally as long as it did before the fatigue.

FALSE

An action potential introduced at the neuromuscular junction is propagated along the sarcoplasmic reticulum. True False

FALSE

Atrial contraction accounts for most of the ventricular filling. A) True B) False

FALSE

In response to an action potential entering the neuron, calcium ions diffuse from the sarcolemma into the sarcoplasm. True False

FALSE

It takes about twice as long for a muscle to contract as it does to relax.

FALSE

TRUE OR FALSE? in relaxed muscle the H zone is at its narrowest width?

FASLE

An action potential introduced at the neuromuscular junction is propagated along the sarcoplasmic reticulum. True False

False

An action potential introduced at the neuromuscular junction is propagated along the sarcoplasmic reticulum. (11)

False

Atrial contraction accounts for most of the ventricular filling? True or false

False

Bone building cells beneath the endosteum lay down bone to form ridges around a blood vessel.

False

In a relaxed muscle, the H zone is at its narrowest width.

False

In a relaxed muscle, the ends of the actin filaments overlap.

False

In a relaxed muscle, the ends of the actin filaments overlap. T/F

False

In fully contracted muscles, the actin filaments lie side-by-side.

False

In response to an action potential entering the neuron, calcium ions diffuse from the sarcolemma into the sarcoplasm. True False

False

In response to an action potential entering the neuron, calcium ions diffuse from the sarcolemma into the sarcoplasm. (11)

False

T/F? Receptors that bind the neurotransmitter at the post-synaptic cell membrane are voltage-gated.

False

The audible heart sounds are caused by the contraction of the atria and ventricles. True or false

False

The beginning of ventricular systole is when the blood flowing back toward the relaxed ventricles causes semilunar valves to close. True or false

False

The distance from one sarcomere to another is called the Z-line.

False

The voltage-gated potassium channels close before the membrane potential is brought back to its resting level.

False

True or False Anna Garcia was taking her blood pressure medication at the time of her death

False

True or False: Calcium couples the neural excitation to the contraction of the muscle by binding the tropomyosin which causes the troponin to move off the actin binding sites

False

True or false. An action potential in a cardiac muscle fiber is identical to an action potential in a skeletal muscle fiber

False

An action potential introduced at the neuromuscular junction is propagated along the sarcoplasmic reticulum (T/F)

False An action potential introduced at the neuromuscular junction is propagated along the SARCOLEMMA of the skeletal muscle

In a relaxed muscle, the H zone is at its narrowest width (T/F)

False H zone is at its WIDEST width when relaxed

A dark band formed by parallel thick filaments that partly overlap the thin filaments is known as an H band. (T/F)

False I Band?

In fully contracted muscles, the actin filaments lie side-by-side. (T/F)

False In RELAXED muscles, the actin filaments lie side-by-side

In a relaxed muscle, the ends of the actin filaments overlap. (T/F)

False In a FULLY CONTRACTED, the ends of the actin filaments overlap.

In response to an action potential entering the neuron, calcium ions diffuse from the sarcolemma into the sarcoplasm (T/F)

False In response to an action potential entering the neuron, calcium ions diffuse from the SARCOPLASMIC RETICULUM into the sarcoplasm

Receptors that bind the neurotransmitter at the post-synaptic cell membrane are voltage gated (T/F)

False Ligand-gated

endomysium

Fibrous connective tissue: the WHAT that surrounds each muscle fiber; loose reticular fibers

How is the shape of the myosin molecule adapted to its role in muscle contraction? (4)

Fibrous protein long and thin; provides surface area for which actin can move along; Globular proteins form bulbous structures; Allows it to exactly fit the binding sites of the actin filament

*Separates* the *atria* from the *ventricles*

Fibrous skeleton

Pulmonary Circulation

From heart to lungs (deoxygenated blood) Pulmonary artery Pulmonary vein Right atrium Right ventricle Lung capillaries

During contraction, the actin myofilaments slide toward the...

H Zone

During contraction, the actin myofilaments slide toward the...

H zone

Describe how the banding pattern will be different when the muscle fibril is contracted. (2)

H zone narrows; Light band narrows

What are the areas in the center of the A bands containing only thick filaments?

H zones

What do H zones and I Bands contain?

H zones contain only myosin I bands contain only actin

What changes occur to a sarcomere when a muscle contracts? (3)

I-band becomes narrower; Z-lines move closer together (sarcomere shortens); H-zone becomes narrower

Using what you know about motor units. Lets say you have two different ones A and B. A is size 3 and B is size 9. If you wanted to lift a heavy object what would you use? If you wanted to lift a light object what you do?

If you wanted to lift a heavy object you would use B. If you wanted to lift and EVEN heavier object you could use both A and B. Light objects you would use A. For a smooth muscle contraction you would want a higher frequency. But based on how you want the muscle to move, depends on how much and what size motor unit you use. This is a learned response.

Hemodynamics

Important for delivery of nutrients and oxygen, and removal of metabolic wastes - Physical principles of blood flow based on pressure and resistance • F ∝ ∆P/R (F = flow, ∆P = difference in pressure, R = resistance) • The greater the pressure difference between two points, the greater the flow; the greater the resistance, the less the flow

What causes skeletal muscle cells to contract? Impulses from motor neurons. Impuses from the heart. Impulses from smooth muscle fibers. Scientists do not know.

Impulses from motor neurons.

Which of the following statements concerning types of muscle contractions is false? In isometric contractions, the amount of tension produced by the muscle is constant. In isotonic contractions, the muscle fibers shorten. The contractile processes in isometric and isotonic contractions are the same. Most skeletal muscle contractions are a combination of isometric and isotonic contractions. In isotonic contractions the amount of tension produced by the muscle fibers is constant during the contraction.

In isometric contractions, the amount of tension produced by the muscle is constant.

In smooth muscle calcium ions binds to?

In smooth muscle it binds with calmodulin

Which of the following statements is true concerning calcium ions? In smooth muscle, it binds with calmodulin. In skeletal muscle, it binds with calmodulin. In smooth muscle it binds with troponin. In skeletal muscle, it binds with tropomyosin. In smooth muscle, it binds with myosin light-chain kinase.

In smooth muscle, it binds with calmodulin.

H band

In the middle of the A band, there is a lighter region called the WHAT, into which the thin filaments do not reach. Thick but no thin filament.

Myasthenia gravis

In this disease, which is fairly common especially among young women, polyclonal antibodies attack the acetylcholine receptor (a-bungarotoxin binding site) of the post-synaptic membrane of the neuromuscular junction. This is unwholesome, since binding of acetylcholine is blocked, and receptors are degraded too rapidly. Interestingly, about 30% of these patients have a thymoma, and most of the rest have thymic hyperplasia (i.e., germinal follicles in the thymus gland).

The training regimen of a competitive weight lifter is designed partly to

Increase the average number of myofibrils per muscle fiber.

What happens to the tension of a muscle during an isometeric twitch when you vary the frequency of APs?

Isometeric contraction, trying to lift something but can't. You contract but muscle does not shorten. Then you give up and relax. Sorta what we are seeing here. If you hit it with an AP, you get at twitch, hit it with another one get a twitch. If you hit it twice with 2 APs, you will see. The first part is exactly like the twitch you have seen, but when we hit it again it goes up higher. If we hit it with a bunch of forces then we see maximal contractability and it is Tetanized. Treppe-a rockier road going up, until you get tetanuization. At this point either fatigue sets in or we stop stimulating and and it goes back into relaxation.

How do we get the graph?

Isometric tension developed depends on the length of the muscle. If a muscle or muscle fiber was clamped between two fixed ends, stimulated electrically to contract and the resulting tension measure and this was repeated as the distance between the fixed clamps (note: affects muscle length) was progressively increased (i.e., the muscle is stretched) in small increments, then the relationship between muscle (sarcomere) length and isometric developed tension could be plotted.

What are the three types of muscle contraction?

Isotonic, Eccentric, Isometric

During which complete phase of the cardiac cycle do both the atria and ventricles relax?

Isovolumetric - ventricles relax Immediately after the ventricular systole, the ventricles and atria are relaxed while all of the valves remain closed. Therefore, the volume of blood inside the ventricles remains the same.

Which of the following is the correct sequence of events regarding the cardiac cycle?

Isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling When the ventricles begin to contract, the volume of blood remains the same because the atrioventricular and semilunar valves are closed at the same time. This is isovolumetric contraction. Once the pressure opens the semilunar valves, blood is ejected. When the contraction ceases, the semilunar valves close and the atrioventricular remain closed, so the blood volume doesn't change. This is isovolumetric relaxation. At full relaxation, the atrioventricular valves open and blood passively travels from the atria to the ventricles. Finally, the atria contract and actively force the remaining atrial blood into the ventricles.

The steps of the cardiac cycle sequence is?

Isovolumic contraction,ejection, isovolumic relaxation,passive ventricular filling, active ventricular filling

Which of the following best describes the role of Ca2+ in muscle contraction?

It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.

Which of the following best describes the role of Ca2+ in muscle contraction? -It binds to tropomyosin, moving troponin, so that myosin heads can bind to actin. -It binds to tropomyosin, moving troponin, so that actin heads can bind to myosin. -It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin. -It binds to troponin, moving tropomyosin, so that actin heads can bind to myosin. -It binds to actin, moving myosin, so that troponin can bind to tropomyosin.

It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.

Which of the following best describes the role of calcium in muscle contraction?

It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.

Electrolytes and HR

K (potassium) has greatest effect 1. Excess = lowered HR 2. Deficiency = requires more stimulation 3. Both are NEGATIVE chronotropic factors Calcium 1. Excess = decreased HR (negative factor) 2. Deficiency= raises HR (positive factor)

Where is myosin's ATPase activity?

Located in myosin heads-globular part, by hydrolyzing ATP myosin can alter its conformation by pivoting around the hinge region of the molecule. So the energy supplied by the hydrolysis of the ATP causes a change in the 2 dimensional structure of the myosin molecule

What is the thin filament?

Made of multiple proteins Actin, tropomyosin, troponin,

Left atrioventricular valve

Mitral

Why is energy needed for muscle contraction? (2)

Movement of myosin heads; Reabsorption of calcium ions into endoplasmic reticulum by active transport

Epimysium covers

Muscle

The characteristic reddish brown color of skeletal muscle comes from which substance?

Myoglobin

The thick filaments of the sarcomere are made up mostly of the protein ____________.

Myosin

What is the site of ATP binding and hydrolysis? -Troponin -Tropomysin -Actin -Myosin

Myosin

contractile proteins

Myosin and actin are called WHAT because they do the work of shortening the muscle fibers. When myofibrils shorten, muscle shortens (contracts)

Cross bridges form between binding sites on actin myofilaments and

Myosin heads.

Energy produced when ATP is converted to ADP and phosphate is stored in

Myosin heads.

A conformational change to troponin-tropomyosin reveals binding sites for _________ located on the ____________.

Myosin, Actin filaments

Thick Filaments

Myosin, Myosin heads, Light chains, H band and M line.

which type of ion channels carry the muscle potential along the surface of the sarcolemma and down the T-tubules?

Na+

How is an action potential created across a neuromuscular junction? (6)

Nerve impulse received at neuromuscular junction; Synaptic vesicles fuse with presynaptic membrane; Release acetylcholine which diffuses to receptors on postsynaptic membrane; Alters its permeability to sodium ions; Sodium ions diffuse in and cause depolarisation; Acetylcholine broken down by acetylcholinesterase

Outline how a muscle relaxes. (3)

Nervous stimulation ceases; Calcium ions actively transported back into endoplasmic reticulum using energy from the hydrolysis of ATP; Absense of calcium ions allows tropomyosin to block binding sites on actin filaments again

Are both sets of valves open during any part of the cycle?

No

The myosin head is bound to __________ during the power stroke.

No Nucleotide

Blood pressure (BP)

Normal value: 120/75 the force that blood exerts against a vessel wall two pressures recorded: Systolic pressure Diastolic pressure

Which of the following is true? The greater the overlap of actin and myosin, the stronger the contraction. Overstretching a muscle will increase its tension. Optimal actin and myosin overlap will produce maximal contraction. The greatest amount of tension is achieved when actin and myosin do not overlap. Tension is great when actin and myosin overlap as much as they can.

Optimal actin and myosin overlap will produce maximal contraction.

quadratus lumborum

Origin: iliac crest Insertion: transverse processes of lumbar vertebrae L1-L4; lower margin of 12th rib

popliteus

Origin: lateral condyle of femur and lateral meniscus Insertion: proximal tibia

sternocleidmastoid

Origin: manubrium of sternum and medial clavicle Insertion: mastoid process; superior nuchal line of occipital bone

buccinator

Origin: molar region of maxilla and mandible Insertion: orbicularis oris

temporalis

Origin: temporal fossa Insertion: coronoid process of mandible

scalenes

Origin: transverse processes of cervical vertebrae Insertion: anterolateral portion of first two ribs

masseter

Origin: zygomatic arch and zygomatic bone Insertion: angle and ramus of mandible

levator labil sperioris

Origin: zygomatic bone and infraorbital margin of maxilla Insertion: skin and muscles of upper lip

In a fully contracted sarcomere, the actin myofilaments

Overlap.

ECG waveforms

P wave QRS complex T wave

2nd degree Heart Block Type 2

P with no R, much more serious, purkinje dx - electrical impulses cannot reach the ventricles, pacemaker may be needed

Phase 1

Partial Repolarization - Na+ channel closes and K+ begins to flow out due to the depolarization which stops the obstacle for K diffusion

Pacemaker Action Potential phases

Phase 0 - depolarization skips 1&2 Phase 3 - repolarization Phase 4 - slow depolarization

What is released when myosin heads attach to actin filaments?

Phosphate.

Trained sprinters have high levels of phosphocreatine in the muscles. Explain the advantage of this. (4)

Phosphocreatine stores phosphate; Used to generate ATP from ADP in anaerobic conditions; Sprinter's muscles often work strenuously and so oxygen supply is short; Phosphocreatine allows for production of ATP to continue when anaerobic respiration is not possible

AV sends impulse to specialized muscle fibers called

Purkinje fibers

heart rate

Raised by positive chronotropic factors Lowered by negative chronotropic factors • Pulse - surge of pressure produced by heart beat that can be felt by palpating a superficial artery - Young adult females average 72 to 80 bpm - Young adult males average 64 to 72 bpm

Ryanodyne

Receptor foundi n the sarcoplasmic reticulm that is activated by DHP, helps release Ca from Sarcoplasmic reticulum down it concentration gradient.

Elasticity

Refers to this tendency of a muscle cell to return to the original length when tension is released

Phase 3

Repolarization occurs (Phase 3) as K+ channels open thereby increasing the outward, hyperpolarizing K+ currents. At the same time, the L-type Ca+ channels become inactivated and close, which decreases gCa+ and the inward depolarizing Ca+ currents.

What is Titan?

Responsible for the resting tension. As you keep stretching the muscle, Titan want to resist that stretch. The primary thing for range of motion after ligament and bone problems is probably going to be do to Titan. The amount of expression of titan can cause pathologies. Largest protein attaches to Z line and goes out to H band.

What receptor does Ca+ bind to?

RyR - Ryanodine receptors - causes more Ca+ to be released from SR

In the heart, an *action potential originates* in the..

SA (sinoatrial) node Electrical conduction through the heart begins with an automatically generated *depolarization of the sinoatrial node*

The plasma membrane of the muscle cell is called the Sarcolemma Triad Terminal cisternae Sarcoplasmic reticulum T tubules

Sarcolemma

The specific name for a muscle fibers plasma membrane is the ________.

Sarcolemma

An action potential for a muscle cell is propagated along the

Sarcolemma.

The muscle cell membrane is called the

Sarcolemma.

The distance from one Z disk to the next Z disk is called a(n)...

Sarcomere

The area between two Z discs is termed a(an)

Sarcomere.

Calcium ions released from the sarcoplasmic reticulum enter the

Sarcoplasm.

Terminal Cisternae are a structural feature of the organelle called the ____________ _____________.

Sarcoplasmic Reticulum

Interconnecting tubules of endoplasmic reticulum that surround each myofibril are called Sarcolemma Triad Terminal cisternae Sarcoplasmic reticulum T tubules

Sarcoplasmic reticulum

An action potential causes calcium ions to diffuse from the ____ into the ____

Sarcoplasmic reticulum; sarcoplasm

Which of the following statements about second-class levers is correct? Second-class levers work at a mechanical disadvantage. Second-class levers have a wide range of motion. Second-class levers have great strength but are slow and have little range of motion. Second-class levers are speed levers.

Second-class levers have great strength but are slow and have little range of motion.

Why does the structure of muscle allow it to perform its function of contraction efficiently? (1)

Separate muscle cells are fused into muscle fibres; so there are no points of weakness

*Separates* the *right atrium and ventricle* from the *left atrium and ventricle*

Septum

S2

Similunar valves close

Which of the following is the correct sequential path of an action potential in the heart?

Sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, Purkinje fibers

What is the type of muscle that is used consciously? (1)

Skeletal muscle

What is the Length-Tension Relationship in Muscle Isometerically? Describe it in a graph length vs tension.

Skeletal muscle->is ideally at the top of the curve. When completely extended it is at the descending part D, When in the curl it is in the Ascending part B. This is most important for the heart. It you fill it too much you will be on the descending part of curve, if you fill too little it will be on the ascending.. Tension developed depends on the length of the muscle. The more you stretch the muscle fiber and increase the length, the greater the tension until a certain point where there is no substantially tension bc the sacromere has been pushed too far.

Which of the following statements is INCORRECT? Skeletal muscles are responsible for the pumping action of the heart. Skeletal muscle contractions help maintain body temperature. Skeletal muscles form valves regulating the passage of substances through internal openings of the digestive and urinary tracts. Skeletal muscles support the weight of some internal organs. The contractions of skeletal muscles pull on tendons and move elements of the skeleton.

Skeletal muscles are responsible for the pumping action of the heart.

motor neurons

Skeletal muscles are served by nerve cels called WHAT, whose cell bodies are in the brainstem and spinal cord. Each nerve fiber branches out to a number of muscle fibers, but each muscle fiber is supplied by only one motor neuron. (Stimulate muscle fibers to contract; axons branch to innervate many fibers; neuromuscular junction)

How do slow-twitch fibres differ from fast-twitch fibres in the way they function? (6)

Slow-twitch fibres: Contract more slowly; Provide less powerful contractions; Over a longer period; Fast-twitch fibres: Contract more rapidly; Produce powerful contractions; For a short period

In response to acetylcholine binding, ____________ move into the muscle fiber causing the membrane potential to rise.

Sodium ions

The neurotransmitter at the neuromuscular junction increases permeability of the muscle cell membrane to

Sodium ions.

What causes the systolic sound

Sound of turbulent blood flow as it first begins to move through the constricted artery

Extensibility

Stretching a muscle, Increasing I-band length and Increasing sarcomere length.

A bands

Striated muscle has dark WHAT? A dark band; full length of thick (myosin) filament. Each A band consists of thick filaments lying side by side. Part of the A band, where thick and thin filaments overlap, is especially dark. In this region, each thick filament is surrounded by thin filaments. (Dark band formed by parallel thick filaments that partly overlap the thin filaments)

Acetylcholine diffuses across the ___________ before binding to its receptor located on the _____________.

Synaptic Cleft; Motor end plate

Cardiac cycle

Systole: 1. Isovolumetric contraction 2. Ejection Diastole: 3. Isovolumetric relaxation 4. Rapid filling (Passive ventricular filling) 5. Atrial contraction (Active ventricular filling )

Heart: two cycles

Systole: contraction Diastole: relaxation

An action potential enters the depths of a muscle fiber by way of __________. (11)

T tubules

Invaginations of the sarcolemma that projecting deep into the cell are called Sarcolemma Triad Terminal cisternae Sarcoplasmic reticulum T tubules

T tubules

Isovolumetric relaxation

T wave ends, ventricles expand, ventricles not taking in blood because both semilunar and AV valves are closed

Structures to create Muscles Contractions

T-Tubule -Invaginations of the sarcolemma penetrating deep into the interior of the muscle cell. Synaptic Cleft -the space between the axon terminal and the motor end plate. Axon Terminal -the swollen distal end of the motor neuron axon. Sarcolemma -the muscle cell membrane. Synaptic Vesicles -structures within the axon terminal that contain the neurotransmitter acetylcholine (ACh). Terminal Cisternae & Sarcoplasmic Reticulum (SR) -structures within skeletal muscle cells that serve as reservoirs of calcium ions. Motor End Plate -a folded region of the sarcolemma at the neuromuscular junction.

An action potential enters a neuron by

T-Tubules

An action potential enters a muscle cell at the

T-tubule.

The active transport of Ca2+ into the sarcoplasmic reticulum requires ATP.

TRUE

The sequence of cross bridge formation and myofilament movement will be repeated as long as calcium ions are present. TRUE FALSE

TRUE

The sliding filament model explains how myofilaments slide past each other. T OR F

TRUE

What is tatanus and how can it generate muscle fatigue? What is Treppe

Tetanus is a sustained maxium contracton of muscle fiber that results from stimulation of a muscle fiber at a high rate. If the frequency of stimulation incresaes, the more and more calcium accumulates within the cell. This permits contraction to continue without relaxation until the maximum number of cross bridges are formed. Tension remains at a plateau. Treppe-observed at high but some what lower rates of stimulation, a rise and small fall in tension may be observed which produces what looks like a staircase phenomenon. Max tension is mantained until the supply of ATP is impaired and the muscle then begins to fatigue. Muscle fatigue results in decrease in the strength of contraction, despite a high stimulation rate due to decrease in concentration of ATP. ATP supply depends on availability of substrates. Different types of muscle fibers vary in their susceptibility to fatigue.

What is a Action Potential?

The ELECTRICAL SIGNAL consisting of the DEPOLARIZATION & subsequent REPOLARIZATION of a nerve or muscle cell membrane.

What about H zones and I bands is TRUE:

The H zones contain only myosin, while the I bands contain only actin.

Which of the following statements about H zones and I bands is TRUE?

The H zones contain only myosin, while the I bands contain only actin.

calcium ions

The SR is a reservoir of WHAT; it has gated channels in its membrane that open at the right times to release a flood of calcium ions into the cytosol, where the calcium activates the muscle contraction process. The T tubule signals the SR when to release the calcium bursts.

What happens at the NM Junciton when the AP arrives at the axon terminal?

The VOLTAGE change of the membrane OPENS VOLTAGE-GATED CALCIUM CHANNELS, allowing Calcium ions to enter the axon terminal.

Which of the following events occurs during the latent phase of a muscle twitch? Muscle fibers shorten. Cross-bridges form, move, release, and reform many times. The action potential is propagated from presynaptic to postsynaptic terminal. Calcium is pumped back into the sarcoplasmic reticulum. All of these occur in the latent phase.

The action potential is propagated from presynaptic to postsynaptic terminal.

Click on the "Short (mm)" button in the Journal to display a graph of your data. Look at your graph and determine the relationship between the amount of muscle shortening and weight

The amount of muscle shortening generally decreased as the weight was increased.

Which of the following is caused by ventricular contraction?

The atrioventricular valves close, and then the semilunar valves open. When the ventricles contract, the walls of the ventricles come together, releasing tension on the chordae tendineae. In addition, the pressure inside the ventricles greatly increases. The decrease in tension and the increase in pressure causes the atrioventricular valves to close. The increase in pressure also causes the semilunar valves to open into the ascending aorta and pulmonary trunk.

Ventricular systole causes

The atrioventricular valves to close , and then the semilunar valves to open

sacroplasm

The cytoplasm of a muscle fiber is called the WHAT.

Which one of the following statements about skeletal muscle contraction is incorrect? (p. 9)

The cytosolic concentration of Ca2+ in resting muscle is typically high.

Explain the relationship between muscle length and tension via the Sliding Filament Theory

The degree of passive stretch (length) of the muscle determines the relationship between the thick and thin filaments. The amount of OVERLAP determines the number of potential cross bridges that may be formed. At short L, there is overlap of the thin filament into the region of the thick filament center with no mysoin heads or cross bridges. As the length increases to Lo, more and more possible cross bridges may be formed. When Lo is is exceeded, then there will be myosin heads in the center of the sacromere that can't bind to actin sites and the number of the potential cross bridges are reduced.

What is a sarcomere? (1)

The distance between adjacent Z-lines

Which of the following is equivalent to the ventricular volume during isovolumetric contraction?

The end diastolic volume (EDV). Isovolumetric contraction occurs at the beginning of ventricular systole when the ventricular volume is at its maximum value−the end diastolic volume (EDV). Because no volume changes occur during isovolumetric contraction, ventricular volume remains at this value throughout the phase.

epimysium

The fibrous connective tissue sheath, which encloses a whole muscle

Describe the Sliding Filament Theory

The length of muscle determines the relationship between the thick and thin filaments. The amount of overlap determines the number of potential cross bridges that may be formed A short L, there is overlap of thin filament into the region of the thick filament with no myosin head or cross bridges. As the length is increased towards Lo more and more possible cross bridges may be formed , when Lo is exceed then there will be mysoin heads in the center of the sarcomere that can't bind to actin sites and the number of potential cross bridges are reduced.

Why does the unstretched muscle produces a relatively weak contraction? The overlapping thin filaments from opposite ends of the sarcomere, interfere and conflict with each other. This restricts productive cross bridge building and less tension develops. The thin filaments are pulled almost to the ends of the thick filaments where little tension can be developed. There is an optimum overlap of thin and thick filaments so that all cross bridges can participate in the contraction.

The overlapping thin filaments from opposite ends of the sarcomere, interfere and conflict with each other. This restricts productive cross bridge building and less tension develops.

sarcolemma

The plasma membrane of a muscle fiber is called the WHAT? Cell membrane that surrounds the sarcoplasm (cytoplasm). Contains many organelles, abundance of myoglobin, filled with intracellular fluid, storage of glycogen, forms openings which dip down into the cell.

How does summation occur? Why is the second peak higher than the first peak when two AP are stimulated close to one another? What is tetanized muscle?

The slack is out of the system, so the second action potential doesn't have to waste any energy and can get a larger force for APs. Also bc the two APs were so close to one and another, more Ca channels were opened, stimulating more muscle contraction. At tetanus-either we have released as much Ca as we possible could or that all the cross bridges are used up, either way it is the maximum amount of tension a muscle can generate. A tetanized muscle is often 3-4 times more tension than a single twitch.

M line

The thick filaments originate at a dark WHAT in the middle of the H band. Protein to which myosins attach. Origin of the thick filaments.

Why does the overstretched muscle produces a little muscle tone? The overlapping thin filaments from opposite ends of the sarcomere, interfere and conflict with each other. This restricts productive cross bridge building and less tension develops. The thin filaments are pulled almost to the ends of the thick filaments where little tension can be developed. There is an optimum overlap of thin and thick filaments so that all cross bridges can participate in the contraction.

The thin filaments are pulled almost to the ends of the thick filaments where little tension can be developed.

What structures do the calcium ions bind to when muscle contraction is initiated?

The troponin molecule

Which structure do the calcium ions bind to when muscle contraction is initiated? The actin myofilament The troponin molecule The tropomyosin molecule The sarcoplasmic reticulum The sarcolemma

The troponin molecule

Which structure do the calcium ions bind to when muscle contraction is initiated? (11)

The troponin molecule

When the atria contract, which of the following is true?

The ventricles are in diastole. Atrial contraction fills each of the ventricles to their maximum capacity−the end diastolic volume (EDV). This occurs towards the end of ventricular diastole while the ventricles are still relaxed.

What is not true about ventricular systole?

The ventricles relax

Click on the "Work amp * wt" button in the Journal to display a graph of your data. Look at your graph and determine the relationship between work and weight.

The work done by the contraction increased to a maximum value and then decreased.

Why does the moderatly stretched muscle produces maximal tension and contraction? The overlapping thin filaments from opposite ends of the sarcomere, interfere and conflict with each other. This restricts productive cross bridge building and less tension develops. The thin filaments are pulled almost to the ends of the thick filaments where little tension can be developed. There is an optimum overlap of thin and thick filaments so that all cross bridges can participate in the contraction.

There is an optimum overlap of thin and thick filaments so that all cross bridges can participate in the contraction.

contracts

These connective tissues (endomysium, perimysium, epimysium) are continuous with the collagen fibers of tendons. Thus, when a muscle fiber WHAT, it pulls on these collagen fibers and usually moves a bone.

Which of the following statements about the "heads" of the myosin molecules is TRUE?

They can attach to different sites on the actin filament.

How are fast-twitch fibres adapted for their function? (4)

Thicker and more numerous myosin filaments; High concentration of enzymes involved in anaerobic respiration; Store of phosphocreatine, which generates ATP from ADP in anaerobic conditions; So adapted for anaerobic respiration due to a build-up of lactic acid and more intense exercise

F actin, tropomyosin, troponin

Thin filament is composed of 3 major proteins?

What happens after the ACh BINDS to the ACh receptor on the motor end plate?

This causes the channels to OPEN permitting an INflux of Sodium Na+ ions and a small EFlux (out) of Potassium K+ ions. This ion EXCHANGE causes a local Depolarization of the "MOTOR END PLATE"

Duchenne's Muscular Dystrophy

This is a common (one male in 3500), sex-linked recessive trait. One third of cases are new mutations, and no population group is without these people. The fundamental lesion is a lack of dystrophin, an inner-sarcolemmal cytoskeletal component homologous to spectrin and actin, which appears to strengthen muscle cells and keep them from popping when overworked (Nature 349: 69 & 243, 1991; Proc. Nat. Acad. Sci. 90: 3710, 1993). The gene's on Xp21. Although the children appear normal at birth, the muscle is already abnormal, and the problem becomes obvious in early childhood. These boys have symmetric weakness, and must resort to unusual methods to stand up ("Gower's sign"). Fatty growth produces the characteristic "pseudohypertrophy of the calves". Boys become wheelchair-bound by their early teens

Myotonic Dystrophy

This is an autosomal dominant (* chromosome 19: q13.2-13.3, cloned: Science 255: 1253 & 1256, 1992; protein is "myotonin" Science 260: 235, 1993), variably expressed because of other genes, affecting several systems. In some communities, it is as common as Duchenne's. Patients have: weakness, starting in the facial muscles (tiny chins and temples, etc.), eventually atrophy of most muscle groups grip myotonia, with difficulty letting go of keys, handshakes, etc. percussion myotonia (muscles tighten when you rub then) frontal baldness and testicular atrophy (men) a distinctive face ("carp mouth") heart disease early dementia (sometimes) cataracts cardiomyopathy

Tropomysoin

Tm elongated protein consisting of 2 alph helix chains which lie parallel to the actin chains within the groove formed by the 2 parallel actin strands There is one unit of Tm for each 7 G actins Tm functions to cover active sites on the corresponding actin chain to prevent bind of the thick filament to those sites of actin.

Which of the following would not be a possible application to a RoboSnail?

To assist in clam and oyster bed farms in the Atlantic North East.

excitability, contractility, extensibility, elasticity

To carry out the functions of movement, stability, communication, control of body openings and passages, and heat production, all muscles cells have the following characteristics: excitability, contractility, extensibility, elasticity

Outline how a muscle contracts. (6)

Tropomyosin molecule prevents myosin head from attaching to the binding site on the actin molecule; Calcium ions released from the endoplasmic reticulum cause the tropomyosin molecule to pull away away from the binding sites on the actin molecule; Myosin head now attaches to the binding site on the actin molecule; Head of myosin changes angle, moving the actin filament along. ADP molecule is released; ATP molecule fixes to the myosin head, causing it to detach from binding site; Hydrolysis of ATP to ADP by ATPase provides the energy for the myosin head to resume its normal position. This process is repeated further along the actin filaments

During muscle contraction, binding sites for myosin are uncovered by the movement of

Tropomyosin.

In a relaxed muscle fiber, the active sites of actin are blocked by

Tropomyosin.

Calcium ions bind to ___________, which is bound to the thin filaments.

Troponin

During contraction of a muscle, calcium ions bind to the __________.

Troponin

Which of the following is not a filamentous protein? Actin Myosin Troponin Tropomyosin

Troponin

Which of the following isn't a filamentous protein? -actin -myosin -troponin -tropomyosin -troponin and tropomyosin

Troponin "Globular troponin protein"

During contraction of a muscle, calcium ions bind to ...

Troponin Molecule

What structures do the calcium ions bind to when muscle contraction is initiated?

Troponin Molecule

During muscle contraction, calcium ions bind to

Troponin.

The protein that acts as a calcium receptor in skeletal muscle is

Troponin.

Action potential are carried by the Purkinje fibers from the bundle branches to the ventricular walls. True or false

True

After cross-bridges form, phosphate is released and then ADP follows (T/F)

True

An action potential causes depolarization of the T tubule membrane (T/F)

True

An action potential causes depolarization of the T tubule membrane.

True

An action potential causes depolarization of the T tubule membrane. True False

True

Both smooth muscle contractions and skeletal muscle contractions involve thin (actin) filaments sliding over the thick (myosin) filaments.

True

Both smooth muscle contractions and skeletal muscle contractions involve thin (actin) filaments sliding over the thick (myosin) filaments. True False

True

Each myosin protein has a globular head that extends outward from the myosin filament.

True

In a relaxed muscle, the H zone is at its widest width.

True

In the ventricles , the action potential travels along the Interventricular septum to the apex of the heart, where it spreads superiorly along the ventricular walls . True or false

True

Once threshold is reached on the postsynaptic membrane, an action potential is generated and propagated over the muscle cell membrane (T/F)

True

Smooth muscle and skeletal muscle fibers both have their contractions triggered by calcium ions.

True

T tubules are invaginations of the sarcolemma of a muscle cell.

True

T-tubules are invaginations of the sarcolemma of a muscle cell. T/F

True

T/F? In a relaxed muscle, the H zone is at its narrowest width.

True

T/F? Once threshold is reached on the post synaptic membrane, an action potential is generated and propagated over the muscle cell membrane.

True

T/F? The area between the pre-synaptic nerve cell and the post-synaptic muscle cell is termed the synaptic cleft.

True

The are between the pre-synaptic nerve cell and the post-synaptic muscle cell is termed the synaptic cleft (T/F)

True

The area between the pre-synaptic nerve cell and the post-synaptic muscle cell is termed the synaptic cleft. True False

True

The muscle fiber length and the amount of force exhibited by the muscle fiber are directly proportional when the muscle fiber is shorter than its relaxed length.

True

The muscle fiber length and the amount of force exhibited by the muscle fiber are inversely proportional when the muscle fiber is longer than its relaxed length.

True

The p wave of the ECG coincides with ventricular filling. True or false

True

The sequence of cross bridge formation and myofilament movement will be repeated as long as calcium ions are present (T/F)

True

The sequence of cross bridge formation and myofilament movement will be repeated as long as calcium ions are present.

True

The sequence of cross-bridge formation and myofilament movement will be repeated as long as calcium ions and ATP are present.

True

The sequence of crossbridge formation and myofilament movement will be repeated as long as calcium ions are present. T/F

True

Transverse (T) tubules are invaginations of the sarcolemma of a muscle cell.

True

Unflexing of the myosin head requires ATP.

True

When cross bridge form and the muscle fibers contract, the actin myofilament slides past the myosin myofilament (T/F)

True

When cross bridges form and the muscle fibers contract, the actin myofilament slides past the myosin myofilament.

True

When cross-bridges form, and the muscle fibers contract, the actin myofilament slides past the myosin myofilament.

True

the active transport of Ca2+ into the sarcoplasmic reticulum requires ATP

True

Myofibrils are composed of protein filaments called actin and myosin.

True.

The I-band of a sarcomere is widest when a muscle is relaxed.

True.

The semilunar valves close during ?

Ventricular diastole

During what phase of the cardiac cycle does aortic pressure reach its maximum?

Ventricular ejection

During which complete phase of the cardiac cycle do the atria both relax and contract?

Ventricular filling

What event causes the semilunar valves to close?

Ventricular pressure<pressure in the great arteries

T wave

Ventricular repolarization

An action potential reaches the axon terminal causing ____________ to open.

Voltage-gated Ca2+ channels

(Refer to exam q) Figure 1 shows a diagram of part of a muscle myofibril. Name the protein present in the filaments labelled W and X. (1)

W: myosin X: actin

When the semilunar valves are open, what is occurring?

(2) AV valves are closed (3) ventricles are in systole (5) blood enters aorta (6) blood enters pulmonary arteries

sarcoplasmic reticulum

(SR) Most other organelles of the cell, such as mitochondria, are packed into the spaces between the myofibrils. The smooth endoplasmic reticulum, here called the WHAT, forms a network around each myofibril. (It runs longitudinally and surrounds each myofibril. Form chambers called terminal cisternae on either side of T-tubles.)

The activity of the heart depends on intrinsic properties of cardiac muscle and on neural factors. Thus,

(a) vagus nerve stimulation of the heart reduces heart rate (b) sympathetic nerve stimulation of the heart decreases time available for ventricular filling, (c) sympathetic stimulation of the heart increases its force of contraction

The fact that the left ventricular wall is thicker than the right reveals that it

(b) pumps blood against greater resistance

The sequence of contraction of the heart chambers is

(c) both atria followed by both ventricles

(Refer to June 2013 paper) The table shows features of fast and slow muscle fibres. Use information from the table to suggest and explain one advantage of: (i) the high glycogen content of fast muscle fibres (ii) the number of capillaries supplying slow muscle fibres (many).

(i) Glycogen broken down gives lots of glucose for anaerobic respiration; Anaerobic respiration is not very efficient; (ii) Many capillaries give large surface area for oxygen diffusion; Allows high rate of aerobic respiration

(i) What is at the centre of each anisotropic band? (ii) What is at the centre of each isotropic band? (2)

(i) H-zone (ii) Z-line

Myofibrils appear striped due to their alternating light-coloured and dark-coloured bands. (i) What makes up the light coloured bands? (ii) What makes up the dark coloured bands? (2)

(i) Isotropic bands - actin and myosin filaments do not overlap (ii) Anisotropic bands - actin and myosin filaments overlap

Describe the part played by each of the following in myofibril contraction. (i) Tropomyosin (ii) Myosin (4)

(i) Moves out of the way when calcium ions bind; Allowing myosin to bind to actin; (ii) Head of myosin binds to actin and pulls actin past; Myosin detaches from actin and moves further along actin

Use your knowledge of the processes occurring at a neuromuscular junction to explain each of the following. (i) The cobra is a very poisonous snake. The molecular structure of cobra toxin is similar to the molecular structure of acetylcholine. The toxin permanently prevents muscle contraction. (2) (ii) The insecticide DFP combines with the active site of the enzyme acetylcholinesterase. The muscles stay contracted until the insecticide is lost from the neuromuscular junction. (2)

(i) toxin binds to the acetylcholine receptors; acetylcholine can not depolarise the membrane (ii) acetylcholinesterase is unable to breakdown acetylcholine; acetylcholine still available to depolarise the membrane

L type channel

(long) Ca+ channel

excitability

(responsiveness) This is a property of all living cells. When stimulated by chemical signals (neurotransmitters), stretch, and other stimuli, muscle cells respond with electrical changes across the plasma membrane.

Structure of the superior view of the heart

(see picture)

Heart sounds

*"Lub"*= *after the QRS wave* as the *AV valves close* ventricular *systole* *"Dub"*= at the *beginning* of the *T wave as the semilunar valves close* ventricular *diastole*

Myocardial action potential

*Cardiac muscle cells* have a *resting potential of −85mV* They are *depolarized to threshold by action potentials* from the *SA node* *Voltage-gated Na+ channels (fast Na+) open*, and *membrane potential plateaus* at *-15mV* for 200−300 msec. Due to *balance* between *slow influx of Ca2+* and *efflux of K+, more K+ are opened*, and *repolarization occurs* *Long plateau prevents summation and tetanus*

Arteries

*Elastic* arteries- *closer to the heart* - allow *stretch* as blood is pumped into them and *recoil* when ventricles relax *Muscular* arteries: *farther from the heart* - have more smooth muscle in proportion to diameter; also have more resistance due to smaller lumina *Arterioles*: 20−30 μm in diameter; provide the *greatest resistance* - *control blood flow through the capillaries*

Capillaries

*Smallest blood vessel*- 7−10 μm in diameter *Single layer* of *simple squamous epithelium tissue* in wall Where *gases and nutrients* are *exchanged between* the *blood and tissues* *Blood flow* to capillaries is *regulated* by: - *Vasoconstriction* (smaller: less flow) and *vasodilation* (larger: more flow) of *arterioles* - *Precapillary sphincters*

skeletal muscle

WHAT may be defined as voluntary striated muscle that is usually attached to one or more bones.

thin filaments

WHAT slide past the thick ones so that the actin and myosin filaments overlap to a greater degree. In the relaxed state, thin and thick filaments overlap only slightly. Upon stimulation, myosin heads bind to actin and sliding begins.

Neuromuscular Junction

What is the place called where a motor neuron stimulates a muscle cell?

Cardiac cycle

*Ventricular contraction* causes the *AV valves to close*, which signals the *beginning* of *ventricular systole* (Isovolumetric contraction) Semilunar valves remain close *Continued ventricular contraction increases pressure* in the ventricles above the *pressure in the aorta* and *pulmonary trunk* causing the *semilunar valves to open* (ejection) When the *ventricles relax* and their *pressure drops*, *blood flowing back* towards *relaxed ventricle* causes the *semilunar valves to close* which is the *beginning of ventricular diastole* AV valves remain closed When the *pressure* in the *ventricles becomes lower* than the pressure *in the atria*, the *AV valve opens* and *blood flows into the relaxed ventricles* (passive ventricular filling) The *atria* then *contract* and *completes filling* the *ventricle* (active ventricular filling).

Fenestrated capillaries

*Wide pores in vessel walls* that are covered by *mucoprotein* found in *kidneys, endocrine glands*, and *intestines*

Tunica interna

*inner* layer composed of *simple squamous endothelium* on a basement membrane and *elastic fibers*

Tunica media

*middle* layer composed of *smooth muscle tissue*

Tunica externa

*outer* layer composed of *connective tissue*

Pacemaker potential

*slow, spontaneous depolarization* between heartbeats, triggered by *hyper*polarization also called *diastolic depolarization* *At −40mV, voltage-gated Ca2+ channels open, triggering action potential and contraction* *Repolarization* occurs with the *opening* of *voltage-gated K+* channels Rate of depolarization can be modified by: *Epinephrine* and *norepinephrine* increase the production of *cAMP*, which keeps *cardiac pacemaker channels open* - Called *HCN* channels: Hyperpolarization-activated Cyclic Nucleotide-gated channels - *Speeds heart rate* due to *Na+ inflow* *Parasympathetic neurons* secrete *acetylcholine* (ACh), which *opens K+* channels to *slow the heart rate*

Blood vessels

- Arteries - Capillaries - Veins

Isovolumetric contraction

- Atria repolarize, relax and remain in diastole for rest of cardiac cycle - Ventricles depolarize, causing QRS complex, and begin to contract - AV valves close as ventricular blood surges back against the cusps - Heart sound S1 occurs at the beginning of this phase - Cardiocytes exert force, but with all four valves closed, the blood cannot go anywhere

Ventricular ejection

- Begins when ventricular pressure exceeds arterial pressure and semilunar valves open - Pressure peaks in left ventricle at about 120 mm Hg and 25 mm Hg in the right - Ejection lasts about 200 to 250 ms - corresponds to plateau phase of cardiac action potential - T wave of ECG occurs late in this phase - Stroke volume (SV) is about 70 mL • Ejection fraction is about 54% of EDV (130 mL) • 60 mL remaining blood is end-systolic volume (ESV) = EDV - SV

The circulatory system is composed of two components:

- Cardiovascular system - Lymphatic system

EKG deviations indicate

- Myocardial infarction (MI) - Abnormalities in conduction pathways - Heart enlargement - Electrolyte and hormone imbalances

Right side of heart

- Oxygen-poor blood arrives from inferior and superior venae cavae - Blood sent to lungs via pulmonary trunk

Isovolumetric relaxation

- T wave ends and ventricles begin to expand - Blood from aorta and pulmonary trunk briefly flows backward filling cusps and closing semilunar valves • Creates pressure rebound that appears as dicrotic notch in graph of artery pressure • Heart sound S2 occurs • When AV valves open, ventricular filling begins again

Which of the following is true for ventricular systole?

- The ventricles contract - The atrioventricular valves close - Blood flows through the aorta and the pulmonary trunk - The semilunar valves open

Tunics of blood vessels

- Tunica interna - Tunica media - Tunica externa

Ventricular filling

- Ventricles expand and their pressure drops below that of the atria - AV valves open and blood flows into the ventricles - Filling occurs in three phases: • Rapid ventricular filling: first one-third • Diastasis: second one-third; slower filling - P wave occurs at the end of diastasis Atrial systole: final one-third; atria contract - End-diastolic volume (EDV) achieved in each ventricle (about 130 mL of blood)

QRS complex

- Ventricular depolarization - Complex shape of spike due to different thickness and shape of the two ventricles

Veins

- has *most* of the total *blood volume* - *Lower pressure* - *Thinner walls than arteries* - *Larger lumen* - collapse when cut - Need help to return blood to the heart: *Skeletal muscle pump* are *muscles surrounding veins* that help *pump blood* *Venous valves* ensures *one direction of blood flow* *Breathing*: Flattening of the diaphragm at inhalation increases abdominal cavity pressure in relation to thoracic pressure and moves blood toward heart

ST segment

- ventricular systole - Corresponds to plateau in myocardial action potential

Check all those that are characteristic of cardiac muscle.

-Cells are striated -Gap junctions join adjacent cells

Which of the following statements are true about the "heads" of the myosin molecules is TRUE? -they form permanent links with actin filaments correct -they can attach to different sites on the actin filament -they straighten the myosin filaments -they allow the myosin filaments to wrap around each other -none of the above

-they can attach to different sites on the actin filamen

what is the most distinguishing characteristic of muscle tissue?

...

The time interval of atrial systole

0.1 sec

The ventricular contraction period

0.3 sec

The quiescent period, or pause

0.4 sec

The length of a normal cardiac cycle

0.8 sec

In the heart, which of the following apply?

1) Action potentials are conducted from cell to cell across the myocardium via gap junctions (2) the SA node sets the pace for the heart as a whole (3) spontaneous depolarization of cardiac cells can occur in the absence of nerve stimulation

List 3 factors that decrease contractility

1. Acidosis 2. Increased extracellular K 3. Calcium channel blockers

1. The maximum rate of oxygen consumption in the body ___ 2. The percentage of the oxygen uptake at which a significant rise in blood lactate levels occurs ___ 3. Reversible, exercise-induced reduced ability in the muscle to generate force ___

1. Aerobic capacity 2. Lactate threshold 3. Muscle fatigue

electrocardiogram in steps

1. Atrial depolarization begins 2. Atrial depolarization complete (atria contracted) 3. Ventricles begin to depolarize at apex; atria repolarize (atria relaxed) 4. Ventricular depolarization complete (ventricles contracted) 5. Ventricles begin to repolarize at apex 6. Ventricular repolarization complete (ventricles relaxed)

myosin heads

1. Binds to active sites on the actin molecules to form cross-bridges (actin binding site) 2. Attaches rod portion by a hinge region that can bend and straighten during contraction 3. Has ATPase activity: breaks down ATP, releasing energy. Part of the energy is used to bend the hinge region of the myosin molecule during contraction.

What are the steps of excitation-contraction coupling?

1. Calcium diffuses throughout the muscle cell and binds to troponin 2. Troponin changes conformation, moving tropmyosin off the myosin binding site of actin 4. Myosin binds to actin-corss bridge formation 5. ADP and Pi are released and power stroke ensures 6. ATP binds to myosin 7. Myosin release from Actin 8. ATP is hydrolyzed 9. Myosin changes conformation rebinds to actin, ADP and Pi are released and power stroke. 11. Next DHP receptor closes, blocking the exit of Ca from the sarcoplasmic reticulum 12. Remaining calcium is pumped back into the SR by active transport 13. Troponin returns to its non calcium bound conformation, moving tropomyosin back on the actin myosin binding site 14. Muscle is now relaxed.

1. Muscle tension causes shortening ___ 2. Muscle tension does not cause shortening of the muscle ___ 3. Lengthening contraction ___

1. Concentric contraction 2. Isometric contraction 3. Eccentric contraction

What two other proteins are associated with each myosin molecule?

1. Essential light chain-stabilizes the bolular head of the myosin 2. Regulatory light chain-regulates the ATPase activity of the myosin

What are the four phases of Isotonic contractions?

1. Generating the tension, can't move the object 2. Shortening muscle-keeping the same amount of force generated. 3. Isotonic relaxation 4. Isometric relaxation.

flow cycle

1. Isovolumetric contraction: When the ventricles begin contracting the pressure rises above that in the atria and the AV valves close. At this point the semilunar valves are closed and there is no change in ventricular volume. 2. Ejection: When the pressure in the left ventricle rises above that in the aorta, the semilunar valves open and the ventricles eject blood. 3. Isovolumetric relaxation: When the ventricles begin to relax the pressure falls below that in the aorta, the semilunar valves close, and there is no change in ventricular volume. 4. Rapid filling: As the ventricles continue to relax, the pressure falls below that in the atria. Blood that has collected in the atria during ventricular contraction rapidly fills the ventricles. 5. Atrial contraction: The atria eject their final amount of blood in preparation for ventricular contraction

When do we use isometric twitch? Compare and Contrast Isotonic vs Isometric?

1. Mechanical work is performed only during an isotonic contraction. Work =Force x distance 2. No shortening of the contractile elements in isometric contractions-no sliding between thick and thin filaments. Cross bridges are formed and broken but no net change in the relationship between actin and mysoin occurs. No external work is done. Energy consumed results in production of heat. 3. Isotonic muscle contraction must overcome the inertia of the object it is attempting to move by acceleration until a certain velocity is reached. Generally persist longer that isometric. 4. When muscle contracts isotonically and begins to shorten, the relationship between thick and thin filaments is continually changing. The net effect is change the number of potential cross bridges. This explains why a muscle at one position may nor be able to sustain further contractions or maintain isometric tension but may be able to do so at a different position.

Electrical Behavior of the Myocardium

1. Na+ gates open 2. Rapid depolarization 3. Na+ gates close 4. Slow Ca2+ channels open 5. Ca2+ channels close, K+ channels open (repolarization)

conduction system order

1. SA node fires 2. excitation spreads through atrial myocardium 3. AV node fiers 4. excitation spreads down AV bundle 5. Purkinje fibers distribute excitation through ventricular myocardium from outline: a. Sinoatrial (SA) node- located in the R atrium, acts as the pacemaker that initiates each heartbeat and determines heart rate. b. Signals from SA node spread throughout the atria c. Atrioventricular (AV) node- located near the R AV valve, acts as an electrical gateway to the ventricles, also acts as an insulator d. AV Bundle (bundle of His)- pathway which allows signals to leave the AV node, forks into R and L branches, descend towards apex of heart e. Purkinje fibers- spread throughout the ventricular myocardium, distribute the electrical signal to cardiocytes of ventricles, more elaborate in L than R ventricle f. Cardiocytes then pass ions from cell to cell through their gap junctions

heart blood flow

1. blood enters right atrium from superior and inferior venae cavae 2. blood in right atrium flows through right AV vale into right ventricle 3. contraction of right ventricle forces pulmonary valve open 4. blood flows through pulmonary valve into pulmonary trunk 5. blood is distributed by right and left pulmonary arteries to the lungs where it unloads CO2 and loads O2 6. blood returns from lungs via pulmonary veins into left atria 7. blood in left atrium flows through left AV valve into left ventricle 8. contraction of left ventricle (simultaneous with step 3) forces aortic valve open 9. blood flows through aortic valve into ascending aorta 10. blood in aorta is distributed to every organ in the body where it unloads O2 and loads CO2 11. blood returns to right atrium via venae cavae steps 4-6 is the pulmonary circuit steps 9-11 is the systemic circuit

What is the role of troponin and tropomyosin?

1. cross bridge-binding of actin and myosin 2. Roles are to regulate formation of cross bridges this regulation is done using Ca, in absence of Ca, tropomyosin blocks the actin myosin binding sites 3. When Ca is present it binds to TnC, causing a conformational change to the troponin complex that forces torpomyosin to move away from the actin myosin binding iste thus allowing actin to bind to myosin and form the cross bridge.

What is a motor unit? Why are they important?

What percent you decide to use to get a graded response. Motor unit is a single alpha motor neuron and all the muscle fibers that it innervates. don't have to contract all, they can passively contract not due to a AP due to another motor unit contracting It is important bc a single tetanized muscle fiber only increases tension 3 fold due to APs. Using the motor unit, now the body has the ability to increase tension by a lot. Size can vary from very small to large ones size correlates with precision of control need for a particular muscle-smaller units are for fine, precise movements or adjustments like eyeball, large motor units are not very precise -gastronemius for example. works in an all or nothing fashion smaller motor units are activated first, as more tension is need to be generated then more motor units are added-motor units are progressively bigger and produce much more tension per motor unit than the initial ones activated

In a cardiac muscle cell, the membrane potential increases rapidly ?

When sodium gates open and sodium diffuses into the cardiac muscle fiber.

What is a neuromuscular junction? (1)

Where a motor neurone meets a skeletal muscle fibre

What are the borders of the sarcomere?

Z lines

conduction system order (long explanation)

1. the sinoatrial node (SA) is a patch of modified cardiocytes in the right atrium, just under epicardium near the superior vena cava. This is the pacemaker that initiates each heartbeat and determines the heart rate. 2. Signals from the SA node spread throughout the atria, as shown by the red arrows in fig. 19.12 (p. 721) 3. the atrioventricular (AV) node is located at lower end of the interatrial septum near right AV valve. This node acts as an electrical gateway to the ventricles; the fibrous skeleton acts as an insulator to prevent currents from getting to the ventricles by any other route. 4. the atrioventricular AV bundle or bundle of His, pathway by which signals leave the AV node. Bundle forks into right and left bundle branches, which enter the interventricular septum and descent toward the apex. 5. Purkinje fibers are nervelike processes that arise from the lower end of the bundle branches and turn upward to spread through the ventricular myocardium. Purkinje fibers distribute the electrical excitation to the cardiocytes of ventricles. they form a more elaborate network in the left ventricle than in the right.

10 Steps to a Contraction of a Motor neuron (Muscle Cell / Fiber)

1.) ACTION POTENTIAL arrives at the axon terminal. 2.) Calcium ions ENTER the axon terminal. 3.) Synaptic vesicles fuse to membrane of axon terminal. 4.) ACh is released, by EXOCYTOSIS, into the synaptic cleft; then calcium is pumped OUT of axon terminal. 5.) ACh binds to receptor sites on the motor end plate. 6.) Motor end plate becomes depolarized. 7.) Action Potential is initiated on the sarcolemma. 8.) Action Potential propagates along the sarcolemma and down the T-tubules. 9.) Calcium ions are released from the terminal cisternae. 10.) The muscle cell contracts.

Neuromuscular Junction & ACh

1.) An ACTION potential arrives at the axon terminal. 2.) Acetylcholine (ACh) is released from the axon terminal into the synaptic cleft. 3.) The motor end plate is DEPOLARIZED. 4.) The Depolarization triggers an ACTION potential which propagates along the sarcolemma and the T-Tubules. 5.) The Sarcomeres CONTRACT !!!

What two events happen after the Synaptic Vesicles Fuse with the membrane of the axon terminal?

1.) The neurotransmitter ACh contained with the Vesicles is liberated by EXOCYTOSIS into the Synaptic Cleft. 2.) Calcium ions are PUMPED OUT of the AXON TERMINAL.

The maximum amount of work done by the contracting muscle was observed when the muscle was lifting:

120 grams

there are ___ pairs of cranial nerves and ___ pairs of spinal nerves

12:31

Isometeric twitch

1st we start off giving an action potential to the muscle, sticking electrodes in it. AP happen really quickly. Only one AP so it goes back to normal. In response to the action potential, a large amount of Calcium is released into the cell. Ca binds to Troponin C, tropomyosin moves, power strokes move, a few cross bridge periods becasue there is some slack. After the latent period, we see tension is created. Over time Calcium get pumped back into SR. now we start to get relaxation. The Twitch force depends of Calcium concentration. Classic twitch in isometeric contraction

Each actin filament is composed of

2 strands of actin molecules wrapped together

The triads of a muscle fiber consist of

2 terminal cisternae 1 T tubule.

Arrange the following in the proper order in which they occur at the pre-synaptic side of a neuromuscular junction. 1. Calcium ions are released 2. Action potential arrives at the presynaptic terminal 3. Neurotransmitter is released

2, 1, 3 2. Action potential arrives at the presynaptic terminal 1. Calcium ions are released 3. Neurotransmitter is released

List the following structures in order from smallest to largest. 1. muscle fiber 2. myofilament 3. myofibril 4. muscle fasciculus 4, 2, 3, 1 2, 1, 4, 3 3, 1, 4, 2 2, 3, 1, 4 1, 2, 3, 4

2, 3, 1, 4

an ECG tracing of someone with a third degree AV block is best described as a tracing with a ______

2:1 ratio of P waves to QRS complexes

Troponin

3 protein subunits Tn Troponin T-TnT- binds to the other two troponin proteins and to Tm Tropoinin-C-has binding sites for Ca2+ each molecule binds up to 4 calicum, causing a conformational change in the Tn complex which changes the relationship of Tm to actin. Troponin I-functions as an inhibitory protein. When no Ca 2+ is present to bind the Tn-C, the troponin complex allows tropomyosin to cover the active binding site on the actin chain. The binding of Ca causes a conformation change which causes Tn-I to change its position. Tm is then rotated away from the actin binding sites it covers. Tn and Tm are considered regulatory proteins. The advantage of Tn-Tm arrangements is tha the change in conformation f the single Tn complex includes the rotation of the Tm out of the formed by the actin helix and permits the single Tm chain to expose the multiple binding sites on the actin chain that were covered by the single Tm chain.

Arrange the following in the proper order in which they occur at the post-synaptic side of a neuromuscular junction. 1. Action potential is propagated over the muscle cell membrane 2. Depolarization of the post-synaptic membrane 3. Sodium ions move into muscle cell

3, 2, 1 3. Sodium ions move into muscle cell 2. Depolarization of the post-synaptic membrane 1. Action potential is propagated over the muscle cell membrane

How many phrases does a muscle twitch have?

4

How many steps are involved during a muscle contraction?

4

On how many separate occasions is flight believed to have evolved in the animal kingdom? (p. 16)

4

Arrange the following steps for contraction in the correct sequence. 1. The muscle impulse reaches the sarcoplasmic reticulum and calcium is released. 2. Thin filaments are pulled over the thick filaments. 3. Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites. 4. The impulse arrives at the synapse and travels through the transverse tubules. 5. The muscle fiber shortens and contracts. 6. Tropomyosin molecules bind to exposed active sites, linking actin and myosin

4, 1, 3, 6, 2, 5

Incomplete Tetanus

5-10 stimulations per second 15 stimulations per second Wavering or visible relaxation between stimulations

At which of the following ages would calcium loss from bone be more than calcium deposits into bone, even when a high calcium diet is eaten?

50 years old

AV nodal myocytes

50-60bpm

Atrial myocytes

50-60bpm

Complete Tetanus

60 stimulations per second Smooth, sustained contraction Greatest force producing capability

The rate of change of percent maximum tension for muscle fibers is greatest from...

60% - 80% of relaxed length.

Sinus nodal myocytes (bpm)

60-80bpm

What is the average heart rate?

72 BPM

An action potential A occurs when the local potential reaches threshold level. B is not propagated. C has no repolarization phase. D is an example of negative feedback. E can be of varying strengths depending on strength of the stimulus.

A

Cardiac muscle cells are like skeletal muscle cells in that they both A have striations. B depolarize as a result of sodium and calcium influxes. C possess intercalated disks. D lack sarcomeres. E are multinucleated.

A

During exercise, an individual experiences ____________ due to aerobic respiration, and after exercise, this oxygen is replenished with ________________. A oxygen deficit, recovery oxygen consumption B recovery oxygen consumption, oxygen deficit C fatigue, anaerobic respiration D physiological contracture, creatine phosphate

A

During the ___________ phase, the inside of the cell becomes positively charged, and during the _________ phase, the membrane potential returns to its resting value. A depolarization, repolarization B polarization, resting C repolarization, depolarization D active, resting

A

If the resting membrane potential becomes more negative, which of the following has occurred? A hyperpolarization B repolarization C depolarization D isopolarization E hypopolarization

A

Movement of the myosin head while the cross-bridge is attached is called the ________, and the return of the head to its original position after releasing from the cross-bridge is called the __________. A power stroke, recovery stroke B recovery stroke, power stroke C active movement, resting phase D active movement, potential movement

A

Rigor mortis occurs after death because A cross-bridges form but can't release. B calcium is actively transported back to the sarcoplasmic reticulum. C anaerobic respiration is occurring. D myosin levels decline at death. E cross-bridges never form.

A

Smooth muscle and cardiac muscle are similar in that they both A are under involuntary control. B are striated. C are widely distributed in the body. D have multiple nuclei. E are under voluntary control.

A

Tetanus of muscles is described as A action potential frequency is high enough that no relaxation of muscle fibers occurs. B a muscle produces constant tension during contraction. C a muscle produces an increasing tension during contraction. D a muscle produces increasing tension as it shortens. E a muscle produces tension, but the length of the muscle is increasing.

A

The bond between the actin and myosin head is broken when... A an ATP molecule binds to the myosin head. B an ATP molecule binds to the actin molecule. C an ATP molecule breaks down on the myosin head. D an ATP molecule breaks down on the actin molecule. E ADP and phosphate bind to the myosin head.

A

The condition of painful, spasmodic contractions of muscles is referred to as A cramps. B fibrositis. C fibromyalgia. D muscular dystrophy. E paralysis.

A

The force of a contraction can be increased with _________, which involves increasing the force of contraction of the muscle fibers, as well as with __________, which involves increasing the number of muscle fibers contracting. A summation, recruitment B gradient change, summation C recruitment, communal change D reinforcement, gradient change

A

The outside of the resting plasma membrane is __________ relative to the inside of the resting plasma membrane. A positively charged B negatively charged C electrically neutral D recharged E None of these choices is correct.

A

The sarcolemma is the A cell membrane of a muscle fiber. B cytoplasm of muscle cells. C structural and functional unit of the skeletal muscle cell. D contractile thread that extends the length of the muscle fiber. E protein strand composed of actin.

A

Thin myofilaments are _______ myofilaments, and thick myofilaments are _________ myofilaments. A actin, myosin B tryptin, actin C myosin, sarcomere D myofibril, globular

A

What is the role of pacemaker cells? A can rapidly develop action potentials B shallow invaginations of cell membrane C relatively constant tension maintained for a period of time D intracellular cytoskeleton E enzyme that removes phosphate from myosin

A

The area of the muscle fiber where the actin and myosin myofilaments overlap is the...

A Band

triad

A T tubule and the two terminal cisternae associated with it constitute a WHAT?

The area of the muscle fiber where the actin and myosin myofilaments overlap is the

A band

The area of the muscle fiber where the actin and myosin myofilaments overlap is the...

A band

Which one of the following does not shorten during skeletal muscle contraction? (p. 6)

A band

During muscle contraction, what happens with the A & I band?

A band remains the same and the I band narrows

The area of the muscle fiber where the actin and myosin myofilaments overlap is the

A band.

The region of the sarcomere that contains both actin and myosin myofilaments is called the I band. A band. Z disk. H zone. M line.

A band.

Which region of the sarcomere does not change length between muscle relaxation and muscle contraction?

A band.

What are the regions where thick and thin filaments overlap and correspond to the length of the thick filaments?

A bands

How do you produce smooth contractions at different tensions?

A combination of motor units recruited and stimulation rate provide for smooth contractions at different tensions..

striations

A skeletal muscle exhibits alternating light and dark transverse bands, or wHAT, that result from an overlapping arrangement of their internal contractile proteins.

Elasticity

A stretched muscle returning to its original length, Spring-like effect of muscle and Passively resisting the separation of two bones.

Which of the following is true? Muscle fatigue has no influence on the force of contractions. A threshold stimulus will cause contraction of a muscle fiber. A subthreshold stimulus causes a muscle contraction. Motor units do not obey the "all or none" law. A threshold stimulus will not affect motor units.

A threshold stimulus will cause contraction of a muscle fiber.

actin filaments

A type of myofilaments. Composed primarily of two intertwined strands of a protein called fibrous (F) actin. Each F actin is like a bead necklace- a string of subunits called globular (G) actin. Each G actin has an active site that can bind to the head of a myosin molecule. A thin filament also has molecules of protein called tropomyosin (an elongated protein winds along the groove of the F actin). When a muscle fiber is relaxed, tropomyosin blocks the active sites of six or seven actins and prevents myosin from binding to them. Each tropomyosin molecule has a smaller calcium-binding protein called troponin bound to it.

Which of the following best describes the role of Ca2+ in muscle contraction? Which of the following best describes the role of Ca2+ in muscle contraction? A. It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin. B. It binds to tropomyosin, moving troponin, so that actin heads can bind to myosin. C. It binds to actin, moving myosin, so that troponin can bind to tropomyosin. D. It binds to tropomyosin, moving troponin, so that myosin heads can bind to actin. E. It binds to troponin, moving tropomyosin, so that actin heads can bind to myosin.

A. Ca2+ binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.

In the neuromuscular junction, acetylchoine ... (what happens)

ACh diffuses across the synaptic cleft and binds to ACh receptors on the postsynaptic muscle fiber

Acetylcholine is broken down into acetic acid and choinesterase by choline (T/F)

ACh is broken down into acetic acid and choline by acetylchoine-asterase

What happens to the ACh after it DIFFUSES away from its receptor on the motor end plate?

ACh is then BROKEN DOWN by the enzyme: Acetyl-cholines-ter-ase

During skeletal muscle contraction, if the myosin head group is attached to the thin filament, but the power stroke has not occurred, what is likely to be found in the nucleotide binding site of the myosin head? (p. 8)

ADP + Pi

Cross-bridge formation occurs when the myosin head is bound to __________.

ADP and Pi

The myosin head is bound to _________ when it is in the extended, high energy conformation.

ADP and Pi

What regulated the release of Calcium?

AP travels down the axon ACh is released at nerve terminal, ACh binds to its receptor on the postynaptic cell muscle cell. End plate potential develops depolarizing area above threshold for voltage gated Na channel rapid depolarization spread over entire muscle. SP travels down the T tubes where the Dihydropyridine receptor is activated DHP receptor then activates the Ryanodyne recpetor-found in the sacroplasmic reticulum Ca exits the sarcoplasmic reticulum, down its concentration gradient Immediately Ca pumps begin returning Ca back to the sarcoplasmic reticulum

Tawanda finishes a sprint and suffers great pain in her calf muscles. Her muscle cramps are most likely due to a temporary deficit of

ATP

The absence of ___________ would prevent the myosin head from detaching from the thin filament.

ATP

The myosin head is bound to ________ when it is in the low energy conformation and is not bound to the thin filament.

ATP

Skeletal muscle is made of bundles of fibres. Describe the role of ATP and phosphocreatine in producing contraction of a muscle fibre. (3)

ATP allows myosin to detach from actin; Phosphocreatine allows regeneration of ATP under anaerobic conditions; Phosphocreatine releases Pi to join ADP

Energy is released when... (relates to ATP and ADP)

ATP is broken down into ADP and phospate

Energy is released when

ATP is broken down into ADP and phosphate.

Energy is released when...

ATP is broken down into ADP and phosphate.

People who have McArdle's disease produce less ATP than healthy people. As a result, they are not able to maintain strong muscle contraction during exercise. Use your knowledge of the sliding filament theory to suggest why. (3)

ATP is needed for attachment between actin and myosin; And the movement of myosin heads, which pulls actin along; Myosin heads need to move back to original position

The bond between the active site on actin and the myosin head is broken when an __________.

ATP molecule binds to the myosin head

The actin-myosin bond is broken by the attachment of

ATP.

The first heart sound is a result of the closure of the

AV valves

S1

AV valves close

When the pressure in the ventricles becomes lower than the pressure in the atria... A) the ventricles contract. B) blood flows into the pulmonary trunk. C) blood flows into the aorta. D) the atrioventricular valves open. E) the semilunar valves open.

AV valves open

At what length do you think this muscle would be able to lift the heaviest weight?

About 28 mm

What chemical, released by the nerve, is involved in stimulating the muscle?

Acetyl Choline

ACh is broken done into acetic acid and choline by what enzyme

Acetyl-choline-sterase

The primary neurotransmitter at the neuromuscular junction is

Acetylchoine

What is the name of the neurotransmitter used at a skeletal neuromuscular junction?

Acetylcholine

The neurotransmitter at the neuromuscular junction is

Acetylcholine.

The thin filaments of the sarcomere are made up mostly of the protein _____________.

Actin

Which of the following is not a filamentous protein?

Actin Myosin Troponin Tropomyosin Toponi

Describe the two types of protein filaments. (2)

Actin - thinner and consists of two strands twisted around one another Myosin - thicker and consists of long rod-shaped fibres with bulbous heads

If we cut across a myofibril at certain points, we see only thick myosin filaments. Cut at a different point we see only thin actin filaments. At yet other points we see both types of filament. Explain why (2)

Actin and myosin filaments lie side by side in a myofibril; and overlap at the edges where they meet

Which of the following statements is correct? -Tropomyosin molecules move and expose specific sites on myosin filaments. correct -Actin filaments slide along myosin filaments. -Cross-bridges form between actin and sarcolemma filaments. -Filaments of troponin and tropomyosin slide past one another. -Myosin and actin alternate to form filaments.

Actin filaments slide along myosin filaments

Which of the following statements is correct?

Actin filaments slide along myosin filaments.

Muscle contraction is caused by

Actin filaments sliding past myosin filaments.

Muscle contraction is caused by:

Actin filaments sliding past myosin filaments.

Thin Filaments

Actin, Active sites, Troponin, Tropomyosin and I band.

Increased calcium ion permeability of the presynaptic terminal cell membrane is caused by an

Action potential.

Which is true about the heart conduction system?

Action potentials pass slowly through the atrioventricular node

Which of the following is true concerning the heart's conduction system?

Action potentials pass slowly through the atrioventricular node.

Action potential

Action potentials spread via intercalated discs (gap junctions) *originates* in the *sinoatrial (SA) node* and *travel* across wall of the atrium *to* the *atrial ventricular (AV) node* (stimulates atrial contraction) Action potential *passes slowly through AV node* to give the atria time to contract Then, they *pass rapidly along AV bundle* (which extends from AV node through fibrous skeleton into interventricular septum) *AV bundle divides into left and right bundle branches* and action potentials *descend rapidly* to *apex of each ventricle* along bundle branches Action potential are *carried by the purkinje fibers* from *bundle branches to ventricular walls* The *rapid conduction* from the *AV bundle to the ends of purkinje fibers allows* the *ventricular muscle cells* to *contract simultaneously* providing a *strong contraction*

Inotropic

Affecting the force of muscle contraction. An inotropic heart drug is one that affects the force with which the heart muscle contracts.

When does the CHEMICALLY-GATED ion channel on the motor end plate close?

After a brief period, ACh DIFFUSES away fm its Receptor site (ion channel Closes).

Function/s of muscle tissue includes Produce Skeletal Movement. Skeletal muscle contractions pull on tendons and move the bones of the skeleton. Guard Entrances and Exits. The openings of the digestive and urinary tracts are encircled by skeletal muscles. These muscles provide conscious control over swallowing, defecation, and urination. Maintain Posture and Body Position. Tension or tone in our skeletal muscles maintains body posture. Maintain Body Temperature. The heat released by working muscles keeps our body temperature in the range required for normal functioning. Support Soft Tissues. The abdominal wall and the floor of the pelvic cavity consist of layers of skeletal muscle. These muscles support the weight of internal organs and shield internal tissues from injury. All are true.

All are true.

Cardiac muscle -contracts as a syncytium. -excites itself. -responds in an all-or-none manner. -is only in the heart. -all of the above.

All of the above

What are the various types of Tension?

Almost all this resting tension, is due to titan. Range of motion after ligaments and bone problems are eliminated, has to do with titan. 1. Developed or active tension (formed by cross-bridge formation). 2. Passive or resting tension - This is affected by the elasticity of the muscle tissue and connective tissue that are in parallel and series with the contractile elements (thick and thin filaments). When the maximum resting tension is exceeded, then the muscle will rupture or pull loose from the tendon or bone. 3. Total tension = Active + passive tension

The movement of the sodium ions throughout the Chemically gated ion channel initiates a Depolarization of the motor end plate. What happens after this depolarization is generated?

An ACTION POTENTIAL which propagates along the sarcolemma in all directions and down the T-tubules.

Facioscapulohumeral Dystrophy

An autosomal dominant (* locus 4q35: Am. J. Hum. Genet. Aug. 1992) with varying expressivity, and not lethal. Patients' shoulders and upper arms waste away, beginning in their teens or twenties. Staining muscle with NADH reveals "moth-eaten" or "mottled" myofibers. Other changes are not usually striking.

Correct sequence of smooth muscle contraction

An increase in cytosolic calcium binds to calmodulin in the cytosol. This complex binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin cross-bridges, which bind to the actin filaments' active sites, resulting in contraction.

Correct sequence for skeletal muscle contraction

An increase in cytosolic calcium binds to troponin, which moves tropomyosin from blocking the active sites on the actin filament, which binds with myosin, forming cross-bridges, resulting in contraction.

Becker's Muscular Dystrophy

Another sex-linked muscular dystrophy, caused by milder abnormal alleles at the Duchenne's locus. "Becker's" is defined to be "Duchenne's" in which patients can still walk by their 16th birthday. It's less common than Duchenne's: Lancet 337: 1022, 1991; Am. Heart J. 132: 642, 1996. The problem in most cases is that dystrophin, though present, is mutated into a less-effective form. Dystrophin has several domains which do different things, and Becker's is very heterogeneous. For a recent review, see Brain 125: 4, 2002

2,1,3

Arrange the following in the proper order in which they occur at the pre-synaptic side of a neuromuscular junction: 1. Calcium ions are released 2. Action potential arrives at the presynaptic terminal 3. Neurotransmitter is released

...How does the maximum load relate to the number of cross bridges?

As you increase the weight, velocity decrease of that contraction. More cross bridges need to be formed to create the initial tension, and what is left in cross bridges allows for the speed. Like a centipede carrying a weight. If you have the same weight that you can lift all three points of the length tension relationship, let's say 5 lbs. It is gives you the same max velocity because, you will eventually get enough cross bridges.

sarceolemma

At each end of the fiber, myofibrils are anchored to the inner surface of the WHAT?

Rest

At rest, total (blood) flow is quite constant, and is equal to the cardiac output (5.25 L/min)

Phase 4

At the end of repolarization, when the membrane potential is very negative (about -60 mV), ion channels open that conduct slow, inward (depolarizing) Na+ currents. These currents are called "funny" currents and abbreviated as "If". These depolarizing currents cause the membrane potential to begin to spontaneously depolarize, thereby initiating Phase 4.

Na+ channel dependent

Atria, Ventricles and Purkinje fibers with a fast conduction and slow automaticity

PQ segment

Atrial systole begins about 100 ms after P wave begins. This segment is about 160 ms long and represents the time required for impulses to travel from the SA node to AV node

Electrical activity of heart

Automaticity - automatic nature of the heartbeat *Sinoatrial (SA) node* - *"pacemaker"* located in *right atrium* *AV node and Purkinje fibers* are *secondary pacemakers* of ectopic pacemakers slower rate than the "sinus rhythm"

A child ingested an organophosphate poison used to kill insects. Soon the child's muscles began spastic contractions. Predict what occurred at the synaptic cleft. A decreased release of acetylcholine from presynaptic neurons B increased accumulation of acetylcholine in the synapse C the poison binds to acetylcholine receptors and stimulates them D increased breakdown of acetylcholine in the synaptic cleft E Both increased accumulation of acetylcholine in the synapse and increased breakdown of acetylcholine in the synaptic cleft.

B

An isotonic contraction is described as A action potential frequency is high enough that no relaxation of muscle fibers occurs. B a muscle produces constant tension during contraction. C a muscle produces an increasing tension during contraction. D a muscle produces increasing tension as it shortens. E a muscle produces tension, but the length of the muscle is increasing.

B

Arrange the following in the proper order in which they occur at the pre-synaptic side of a neuromuscular junction. 1 Calcium ions enter presynaptic terminal and cause release of acetylcholine. 2 An action potential arrives at the presynaptic terminal. 3 Diffusion of acetylcholine across the synaptic cleft and binding of acetylcholine to acetylcholine receptors. A 1, 2, 3 B 2, 1, 3 C 2, 3, 1 D 3, 2, 1 E 3, 1, 2

B

During contraction of a muscle, calcium ions bind to... A the actin myofilament. B the troponin molecule. C the tropomyosin molecule. D the sarcoplasmic reticulum. E the sarcolemma.

B

Each actin filament is composed of A a single strand of actin molecules. B two strands of actin molecules wrapped together. C three strands of actin molecules wrapped together. D four strands of actin molecules wrapped together. E hundreds of strands of actin molecules wrapped together.

B

Each presynaptic terminal contains ___________, which contain the neurotransmitter __________ that, when released, cause ligand-gated Na+ channels to open in the postsynaptic membrane. This causes __________ in the muscle cell. A ACh receptors, acetylcholinesterase, repolarization B synaptic vesicles, acetylcholine, depolarization C proteins, acetylcholine, repolarization D mitochondria, acetylcholinesterase, depolarization

B

Energy is released when... A ADP is broken down into ATP and phosphate. B ATP is broken down into ADP and phosphate. C ADP and phosphate combine to form ATP. D ATP and phosphate combine to form ADP. E AMP and two phosphates combine to form ATP.

B

In ___________, muscle fibers partially relax between contractions, and in ___________, no relaxation occurs between contractions. A complete tetanus, rigor mortis B incomplete tetanus, complete tetanus C stretching, incomplete tetanus D rigor mortis, hypotonia

B

Muscle atrophy A involves an increase in the number of muscle fibers. B is characterized by a decrease in muscle size. C results from aerobic exercise. D causes an increase in blood flow to the affected muscle. E is characterized by an increase in muscle size.

B

Sarcoplasm is the A cell membrane of a muscle fiber. B cytoplasm of muscle cells. C structural and functional unit of the skeletal muscle cell. D contractile thread that extends the length of the muscle fiber. E protein strand composed of actin or myosin.

B

The amount of additional oxygen that must be inhaled following exercise to restore pre-exercise conditions is called _______ _________. A Creatine phosphate B Oxygen debt C Lactic acid D Glycogen replenishment

B

The charge difference across the plasma membrane of an unstimulated cell is called the __________. A plasma membrane potential B resting membrane potential C sarcomere potential D charge potential

B

The region of the sarcomere that contains both actin and myosin myofilaments is called the A I band. B A band. C Z disk. D H zone. E M line.

B

What is a triad? A a protein found along the groove of the F-actin double helix B a T tubule and two adjacent terminal cistern C the combination of myosin heads with active sites on actin molecules D the movement of myosin head while attached to actin myofilament E after exercise, the oxygen taken in that exceeds the oxygen required for resting metabolism

B

What structures do the calcium ions bind to when muscle contraction is initiated? A the actin myofilament. B the troponin molecule. C the tropomyosin molecule. D the sarcoplasmic reticulum. E the sarcolemma.

B

Which of the following statements about the "heads" of the myosin molecules is TRUE? A they form permanent links with actin filaments B they can attach to different sites on the actin filament C they straighten the myosin filaments D they allow the myosin filaments to wrap around each other E none of these choices are correct

B

________ occurs when a rested muscle is stimulated repeatedly, at low frequencies, allowing relaxation between contractions. This causes each contraction to be stronger than the previous one until the levels of tension are equal between contractions. A Summation B Treppe C Tensile strength D Complete tetanus

B

Which of the following structures allow one cardiac cell to electronically stimulate another by allowing ion flow across the intercalated disk? A) fascia adherens B) gap junctions C) desmosomes D) intercellular folds

B) gap junctions

This chamber has to work harder than the others, so it has the thickest myocardium: A) right ventricle B) left ventricle C) right atrium D) left atrium

B) left ventricle

Which of the following refers to the cardiac muscle tissue? A) pericardium B) myocardium C) endocardium D) epicardium

B) myocardium

Which of the following is associated with the atria? A) trabeculae carneae B) pectinate muscles C) chordae tendineae D) papillary muscles

B) pectinate muscles

Atrial pressure is at its highest when: A) the AV valve is closed B) the AV valves are open C) the semilunar valves are closed D) the valves have no influence on atrial pressure

B) the AV valves are open

The valve that lies between the right atrium and the right ventricle is the: A) aortic semilunar valve B) tricuspid valve C) mitral valve D) bicuspid valve

B) tricuspid valve

The semilunar valves close during... A) ventricular systole. B) ventricular diastole. C) atrial systole. D) atrial diastole. E) both atrial and ventricular systole.

B) ventricular diastole

The semilunar valves are the valves that prevent the blood from flowing back into the atria when the ventricles contract. A) True B) False

B. FALSE

During crossbridge cycling, tension is created by:

a change in the shape of the myosin head.

Isometric contraction

a contraction where the length of the muscle stays the same we generate tension, not shortening

In this lab, an electrical shock stimulates the muscle, which contracts and lifts the weight. The distance the weight is lifted is measured using:

a displacement transducer.

muscle fibers

Because of their extraordinary length, skeletal muscle cells are usually called WHAT or myofibers.

Myocardial action potential and the Pacemaker potential

Because the pacemaker potential occurs during systole, it can also be called systolic potential *False* *Pacemaker potential* happens during *diastole* The *pacemaker potential* is the *relatively slow, spontaneous depolarization* in the SA node *Myocardial cells* produce their *own action potentials* after being *stimulated by action potentials originating in the SA node*

There is an increase in the activity of the enzyme ATPase during muscle contraction. An investigation into muscle contraction involved measuring the activity of ATPase in solutions containing ATP, myosin and different muscle components. The table shows the results. (Refer to exam q) Explain the importance of ATPase during muscle contraction. (2)

Breaks down ATP, yielding energy; Used to break actomyosin bridges

What is Exocytosis?

Bulk transport of material OUT of cell by 1st FUSEing a membrane-bound vesicle, ( 0 ), w/ plasma membrane . When membrane ruptures , the contents of the vesicle are RELEASED into the extracellular space (or synaptic cleft)

How do snails travel?

By a strong muscular foot along a trail of mucus.

A sarcomere is the A cell membrane of a muscle fiber. B cytoplasm of muscle cells. C structural and functional unit of the skeletal muscle cell. D contractile thread that extends the length of the muscle fiber. E protein strand composed of actin or myosin.

C

An isometric contraction is described as A action potential frequency is high enough that no relaxation of muscle fibers occurs. B muscle produces constant tension during contraction. C a muscle produces an increasing tension as the length remains constant. D a muscle produces increasing tension as it shortens. E a muscle produces tension, but the length of the muscle is increasing.

C

During fused tetanus A a muscle fiber under continuous stimulation and contraction becomes unable to contract at all until it has rested. B muscle fiber stimulations are such that muscle fibers are able to contract and then completely relax before the next contraction. C the stimuli arrive at the muscle fiber so rapidly that there is no muscle relaxation between stimuli, but rather, a continuous contraction of the muscle fiber. D the stimuli arrive at the muscle fiber at such a rate that the muscle fiber is unable to completely relax between stimuli, and sequential contractions exhibit an equal contractive force that is greater than when the muscle fiber is allowed to rest completely. E a second stimulus arrives at the muscle before complete relaxation of the first contraction, causing the second contraction to have greater tension than the first one.

C

One cause of spastic paralysis might be A inhibition of acetylcholine molecules. B blockage of acetylcholine receptors. C inhibition of acetylcholinesterase. D destruction of synaptic vesicles. E increase in the amount of acetylcholinesterase.

C

The constant tension produced by muscles for long periods of time is ___________. A muscle energy B potential energy C muscle tone D myofibril energy

C

The cycle of a mysosin molecule forming cross-bridges, moving, then releasing and returning to its original position is called _____________. A sliding filament model B contraction cycle C cross-bridge movement D myosin exchange

C

The myofilaments that contain two strands of F actin coiled together to form a double helix are ________ myofilaments, and the myofilaments that are composed of molecules that are shaped like golf clubs are _________ myofilaments. A myosin, actin B myosin, myosin C actin, myosin D actin, actin

C

The point where the axon terminal synapses with the muscle fiber sarcolemma is called the _____________. A sarcolemma junction B active site C neuromuscular junction D membrane receptor

C

The primary neurotransmitter at the neuromuscular junction is A dopamine. B adrenaline. C acetylcholine. D histamine. E serotonin.

C

When _________ causes more motor units to contract in a whole muscle as the stimulus strength increases, the relationship between increased stimulus strength and increased number of motor units contracting is called ___________. A summation, tetanus B recruitment, treppe C recruitment, multiple motor unit summation D summation, recruitment

C

Which of the following occurs during recovery from oxygen deficit? A an elevated level of anaerobic metabolism B depletion of reserves of creatine phosphate C conversion of excess lactic acid to glucose D glycogen degradation to provide creatine E depressed level of aerobic respiration

C

perimysium

a fasciculus is surrounded by what type of CT

What is a sarcomere?

a functional unit of skeletal muscle.

I bands

a light band; from Z disks to ends of thick filaments

A motor unit is a motor neuron and all of the muscle fibers it stimulates. a motor neuron and one muscle fiber. all motor neurons in the body. all the muscle fibers in the body.

a motor neuron and all of the muscle fibers it stimulates.

A motor unit is

a motor neuron and the muscle fibers connected to it.

unfused or incomplete tetanus

a muscle stimulated at high-frequency with some short relaxation time between, such that sustained but quivering contractions occur

fused or complete tetanus

a muscle that is stimulated so frequently that the relaxation phase is completely eliminated and smooth, sustained contraction results

actin

a protein in a m. fiber that forms filaments that slide between filaments of myosin, contracting m. fibers

What is myosin?

a protein of the microfibril, most common protein in muscle cells

Ectopic focus

a region of spontaneous firing other than the SA node - May govern heart rhythm if SA node is damaged

PVC on the EKG is

a relatively common event where the heart beat is initiated by Purkinje heartbeat initiator (pace maker) The ventricles contract first before the atria have optimally filled the ventricles with blood, which means the circulation is inefficient with low oxygen to the heart

lever

a rigid bar that moves on a fixed point

define pulse

a ryhthmetic pushing of the blood by the heart which can be measured by the movement of an artery

During twitch summation (aka temporal or wave summation)

a second stimulus arrives at the muscle before complete relaxation of the first contraction, causing the second contraction to have greater tension than the first one.

During twitch summation...

a second stimulus arrives at the muscle before complete relaxation of the first contraction, causing the second contraction to have greater tension than the first one.

Muscle fibers are made up of ______ and _______

a single cell and many nuclei (results from cell fusion)

fascicle

a small bundle of m. fibers

tendon

a structure that connects muscles to bones. A ligament attaches bones to bones.

What is an ACE inhibitor

a type of drug the blocks an enyme that raises blood pressure

Which of the following is the correct sequence for skeletal muscle contraction? A) An increase in cytosolic calcium binds to the troponin complex, which binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin heads, which binds to the actin filaments, resulting in contraction. B) An increase in cytosolic calcium binds to calmodulin in the cytosol, which binds with myosin, forming cross-bridges, resulting in contraction. An increase in cytosolic calcium binds to calmodulin in the cytosol, which moves tropomyosin from blocking the active sites on the actin filament, which binds with myosin, forming cross-bridges, resulting in contraction. C) An increase in cytosolic calcium binds to troponin, which moves tropomyosin from blocking the active sites on the actin filament, which binds with myosin, forming cross-bridges, resulting in contraction. D) An increase in cytosolic calcium binds to calmodulin in cytosol, which binds with myosin light-chain kinase, using ATP to phosphorylate the myosin heads, which bind to the actin filaments, resulting in contraction.

C) An increase in cytosolic calcium binds to troponin, which moves tropomyosin from blocking the active sites on the actin filament, which binds with myosin, forming cross-bridges, resulting in contraction.

The strength of a muscle contraction is determined by the size of motor units being stimulated. the number of motor units being stimulated. the strength of the action potential. a&b are true.

a&b are true.

Ventricular systole causes... A) blood to flow into the ventricles. B) blood to flow out of the atria. C) the atrioventricular valves to close, and then the semilunar valves to open. D) the semilunar valves to close, and then the atrioventricular valves to open. E) pressure to become greater in the aorta and pulmonary trunk than in the ventricles.

C) the AV valves to close, and then the semilunar valves to open.

Describe the Isometric Length Tension Relationship at each key point.

a. A muscle at its passive length (i.e., not stretched at all) develops very little tension. b. As a muscle is stretched (i.e., its length progressively increased) up to some point (Point B on the graph), there is a corresponding increase in the developed tension. When there is perfect overlap between thin and thick filaments, we now can generate the maximum amount of tension. c. There is a optimal length (Lo) where the peak developed tension occurs (Po). That length occurs when the sarcomere length is between 2-2.2 . d. When the muscle length exceeds the Lo, then the developed tension begins to progressively decline (e.g., at Points C and D) steric hinderence can between protein in the thin filament can cause them not to overlap well. seen A If we stretch the sacromere too much, Ca no long stimulate the contraction, bc the thin and thick filaments don't even overlap, no contraction.

What happens when the calcium ion is present in the cytosol of the muscle cell?

CONTRACTION of the muscle cell / fiber (only one cell)

endomysium

CT that surrounds a muscle fiber

Calcium's role in action potential

Ca+ channels open allowing influx into cytoplasm and this triggers the SR to release Ca+ to activate the actin-myosin complex and myofibril contraction. During phase 3 and 4, Ca+ is pumped out of the cell or into the SR

Phase 2

Ca+ moves in slowly along concentration gradient with K going out

What is the ion released from the terminal cisternae that combines with troponin and removes the blocking action of tropomyosin, resulting in the formation of cross bridges? acetylcholine troponin myosin Ca2+ calmodulin

Ca2+

What is the role of Ca2+ in muscle contration

Ca2+ (Calcium) binds to troponin, moving tropomyosin, so that myosin heads can bind to actin

Which of the following does NOT occur during skeletal muscle contraction? ATP is hydrolyzed. Calcium binds to myosin heads. Myosin heads bind to actin. Calcium concentration in the sarcoplasm increases. The I bands shorten and H zones disappear.

Calcium binds to myosin head

What happens as the action potential moves down the T-tubules?

Calcium ions are released from the TERMINAL-CISTERNAE into the CYTOSOL.

What is the effect of the presence of calcium ions inside the axon terminal?

Calcium ions inside the axion terminal cause several Synaptic Vesicles to FUSE w/ the membrane of the axon terminal.

In the carbon nanotube joint replacement alternative, what would provide the bone strength?

Calcium ions that are attracted to the carbon fiber

Uncovering binding sites for myosin on actin myofilaments is involves troponin binding to

Calcium ions.

____________ enter the axon terminal leading to the release of acetylcholine via __________.

Calcium ions; Exocytosis

Intro - Electrical activity of heart

Cardiac muscle cells are interconnected by *gap junctions* called *intercalated discs* Once *stimulation is applied*, the *impulse flows* from *cell to cell* The area of the heart that *contracts from one stimulation event* is called a *myocardium* or *functional syncytium* (network of cells) The *atria and ventricles* are *separated electrically* by the *fibrous skeleton*

Increased calcium concentrates in the cytosol causes?

Contraction of sacromeres

It is essential that both ventricles eject the same amount of blood even though the pressure in the right ventricle is much less than the pressure in the left ventricle. A) True B) False

a. true

When the ventricles relax blood in the aorta flows back toward the heart filling the coronary arteries. A) True B) False

a. true

abducts and extends thumb

abductor pollicis longus

elasticity

ability of a muscle to return to its resting length after being stretched

extensibility

ability to be stretched or extended

excitability

ability to receive and respond to a stimulus

contractility

ability to shorten forcibly when adequately stimulated

toxins from drugs or medications can cause

abnormal heart rate

According to your data, a single contraction produced maximum tension when the muscle was held at

about 28 mm.

Maximum tension is achieved when the muscle is at resting length. According to your data, the resting length of the muscle was:

about 28 mm.

Which of the following statements describe histological characteristics of smooth muscle? presence of visible striations & single, centrally-located nuclei presence of visible striations & multiple peripheral nuclei absence of visible striations & single, centrally-located nuclei number of nuclei

absence of visible striations & single, centrally-located nuclei number of nuclei

The chemical used at the junction with a skeletal muscle is _______.

acetycholine

What is the first step of muscle contraction?

acetyl choline released from lower motor neuron, binds to ligand-gated sodium channels (nicotenic receptors located on the postsynaptic membrane, specifically the motor end plate), causes sodium influx/depolarization and massive EPSP

The primary neurotransmitter at the neuromuscular junction is

acetylcholine

what is the neurotransmitter necessary for muscle contraction

acetylcholine

The first event in muscle fiber contraction is that

acetylcholine is released from the end of the motor neuron

The first event in muscle fiber contraction is that -the muscle fiber membrane is stimulated and a muscle impulse travels deep into the fiber through transverse tubules. -acetylcholine diffuses across a gap at a neuromuscular junction. -acetylcholine is released from the end of the motor neuron. -calcium ions diffuse from sarcoplasmic reticulum into the sarcoplasm and bind to troponin molecules. -morphine is released from the end of the motor neuron.

acetylcholine is released from the end of the motor neuron

The first event in muscle fiber contraction is that

acetylcholine is released from the end of the motor neuron.

When acetylcholine is released into the synaptic cleft, it causes calcium ions enter the axon terminal. causes an action potential to propagate along the sarcolemma and down the T Tubules. causes synaptic vesicles to fuse to the membrane of axon terminal, allowing release of acetylcholine. causes an action potential to be initiated on the sarcolemma. causes calcium ions to be released from the terminal cisternae. acetylcholine to bind to receptor sites on the motor end plate.

acetylcholine to bind to receptor sites on the motor end plate.

Synaptic vesicles found at the synaptic terminal of a nuromuscular junction contain acetylcholine. acetylcholinesterase. sodium. calcium.

acetylcholine.

The primary neurotransmitter at the neuromuscular junction is

acetylcholine.

after nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?

acetylcholinesterase destroying the ACh

has binding sites for myosin heads and slides past the myosin when the head goes through its pull stroke during contraction

actin

Myofibrils are composed primarily of

actin and myosin.

Muscle contraction is caused by

actin filaments sliding past myosin filaments

Muscle contraction is caused by?

actin filaments sliding past myosin filaments

Muscle contraction is caused by

actin filaments sliding past myosin filaments.

Cross-bridges form between the __________ and the __________. (11)

actin filaments; myosin head

Cross-bridges form between the __________ and the __________. troponin; tropomyosin calcium; sodium sarcolemma ; sarcoplasmic reticulum T tubules; sarcolemma actin filaments; myosin heads

actin filaments; myosin heads

The active sites to which cross-bridges attach are found on the sarcoplasmic reticulum. actin myofilaments. Z disks. T tubules. myosin myofilaments.

actin myofilaments.

Which one of the following is a typical component of striated muscle thin filaments? (p. 5)

actin, troponin, tropomyosin

During the contraction phase of a muscle twitch, acetylcholine stimulates the pre-synaptic terminal. sodium ions diffuse into the muscle fiber. actin-myosin cross-bridges form. calcium ions are transported back to the sarcoplasmic reticulum. the action potential travels down the T tubule.

actin-myosin cross-bridges form.

Dihydropyridine receptor

activated via AP that travels down T tubes

Muscles contract _______

actively

Short-term intense movements

activities best suited for fast-glycolytic fibers

sprinting/ walking

activities best suited for fast-oxidative fibers

Stroke Volume

affects CO (cardiac output) 1. Preload- - the amount of tension in ventricular myocardium immediately before it begins to contract 2. Contractility- refers to how hard the myocardium contracts for a given preload 3. Afterload - sum of all forces opposing ejection of blood from ventricle

the muscles that perform most of the action in producing the movement

agonists

Electric signals called action potentials cause a muscle cell to contract. transfer information from cell to cell. make complex mental processes possible. send information to the brain. all are true

all are true

Which of the following is/are true of temporal summation? Temoral summation occurs when a second stimulus of the same intensity is applied to a muscle before the completion of the relaxation period of the first stimulus. In temporal summation, the second peak is higher than the first because the additional influx of calcium ion promotes a second contraction, which is added to the first contraction. If you wait until relaxation is complete from the first stimulus, then give a second stimulus to the same muscle, temporal summation will not occur. Temporal summation results in increased muscle tension. all are true

all are true

The bond between the actin and myosin head is broken when

an ATP molecule binds to the myosin head.

A stimulus either causes an action potential or it doesn't. This is called

an all-or-none response.

According to the sliding filament theory for skeletal muscle contraction, a shortening of the sarcomere is produced by:

an increase in the amount of overlap between the thick and thin filaments.

The _______________ assists the triceps brachii in forearm extension. brachialis pronator teres palmaris longus anconeus

anconeus

Pain or pressure in the chest in response to myocardial ischemia is called...

angina pectoris Angina pectoris is referred pain in response to myocardial ischemia. It is often *treated* with *nitroglycerine*, which causes *vasodilation* and *improves the circulation* back to the heart

stroke volume

another factor in cardiac output, besides heart rate, • Three variables govern stroke volume - Preload - Contractility - Afterload • Examples - Increased preload or contractility increases stroke volume - Increased afterload decreases stroke volume

The muscle that opposes a particular action is called the

antagonist

muscles that relax when the prime mover and synergist are contacting

antagonists

dense body

any of the small regions of increased density in the sarcoplasm of muscles to which myofilaments seem to attach, attachment plaques in smooth muscle cells are believed to be analogous to Z lines, contain alpha-actinin and function as myofilament attachment sites, actin, myosin and intermediate filaments are also present in nonvascular smooth muscle cells (majority), intermediate filaments are desmin, in vascular smooth muscle intermediate filaments are vimentin

Smooth muscle and cardiac muscle are similar in that they both are under involuntary control. are striated. are widely distributed in the body. have multiple nuclei. are under voluntary control.

are under involuntary control.

H band

area in the center of the A band containing only thick filament

I band

area of sarcomere containing only thin filaments

A band

area of the sarcomere with overlapping thick and thin filaments

A motor unit is a motor neuron and all the muscle cells it innervates. So when lifting a heavy weight...

as the muscle works harder to lift the weight more motor units are recruited

What do asynchronous alternate firing and relaxation of different motor units cause vs simultaneous firing ?

asynchronous alternate firing and relaxation of different motor units which result in a smooth contraction. Simultaneous firing tends to produce jerky motion

Muscle tone is maintained by synchronous stimulation of predetermined motor units. asynchronous stimulation of random motor units. stimulation of random motor units by large action potentials. stimulation of random motor units by small action potentials.

asynchronous stimulation of random motor units.

The force of contraction is greatest for a muscle fiber...

at 100% of its relaxed length.

Bones in the legs, arms, spine and pelvis grow

at different rates.

neural stimulation

at presynaptic terminal, stimulates influx of Ca 2+ ions, causes synaptic vesicles to cluster and release contents along specialized linear sites (active zones) in the presynaptic membrane, acetylcholine release from vesicles--> bind to acetylcholine receptors in sarcolemma of muscle cell, cause transient increase in sodium ions, depolarizes muscle cell membrane, generates action potential action potential propagated over sarcolemma into T tubules, activate release of calcium-->contraction acetylcholinesterase in basal lamina lining secondary clefts of motor end plate limits response to neurotransmitter by breaking down acetylcholine

Maximum tension is produced in a skeletal muscle fiber when it is:

at resting length.

Phase 4

at resting potential

The chambers that have just been emptied are the

atria

Immediately after the second heart sound, the ___ and ___ fill with blood

atria and ventricles

S4

atrial contraction (not normal)

P wave

atrial contraction - atrial depolarization

P wave

atrial depolarization

What event within the heart causes the AV valves to open

atrial pressure > ventricular pressure

P-Q interval

atrial systole

T wave

atrial/ventricular muscle repolarization - positive deflection for ventricles, atrial repolarization is obscured by the QRS complex and it is so small it cannot be seen

3rd degree Heart Block

atrium and ventricles beating independently of each other, dissociation of P waves or no normal relationship b/w P and QRS waves

stabilizing joints

attaching to bones and keeping them in close proximity to one another

flexes forearm at elbow joint; supinates forearm

biceps brachil

flexes and laterally rotates leg at knee

biceps femoris

Which valve is heard most clearly when the apical heartbeat is auscultated

bicuspid valve

Action potential at the SA node

bottom: pacemaker potentials left side of peak: voltage-gated Ca channels right side of peak: K channels (see picture)

powerful flexor of forearm

brachialis

Atherosclerosis

build up of lipid deposits that become plaques

An action potential enters a muscle cell ______________________.

by the T-tubules

An electrical impulse travels into the interior of a muscle fiber:

by way of the transverse tubules.

When the atria begin depolarizing, which of the following is occuring? A) ventricular filling B) ventricular ejection C) atrial filling D) atrial ejection

c.) atrial filling

Which mineral is most important throughout life to assist in maintaining strong bone?

calcium

What is the cause of rigor mortis? high levels of sodium in the cell after death diffusion of potassium out of the cell after death calcium influx into the sarcoplasm after death breakdown of protein in the cell after death

calcium influx into the sarcoplasm after death

While the muscle rests...

calcium ions are no longer present at their attachment site.

What happens at the terminal cisternae when the action potential reaches it? Acetyl choline is released into the synaptic cleft. Action potential propagates along the sarcolemma and down the T Tubules. Synaptic vesicles fuse to membrane of axon terminal. Action potential is initiated on the sarcolemma. Calcium ions are released from the terminal cisternae. Acetylcholine binds to receptor sites on the motor end plate. Calcium ions enter the axon terminal.

calcium ions are released from the terminal cisternae.

(Refer to exam q) The diagram shows the stages in one cycle that results in movement of an actin filament in a muscle sarcomere. Describe how stimulation of a muscle by a nerve impulse starts the cycle shown in the diagram. (3)

calcium ions interact with the tropomyosin molecule; to reveal binding sites on actin; allowing myosin heads to bind to exposed sites on actin filament

Using your knowledge of muscle contraction, explain the difference in the results between B and C. (2)

calcium ions remove tropomyosin; to allow binding of myosin heads and actin, increasing ATPase activity

An action potential arriving at the pre-synaptic terminal causes...

calcium ions to diffuse into the cell

Muscle contractions are initiated by the binding of __________ to __________.

calcium ions, troponin

Which one of the following binds calcium ions in a smooth muscle, causing contraction? troponin tropomyosin myosin actin calmodulin

calmodulin

Cross-channel swimmers may suffer from muscle fatigue during which the contraction mechanism is disrupted. One factor thought to contribute to muscle fatigue is a decrease in the availability of calcium ions within muscle fibres. Explain how a decrease in the availability of calcium ions could disrupt the contraction mechanism in muscles. (3)

cannot move tropomyosin; from binding sites on actin; myosin heads do not bind

Nanotubes are made of

carbon atoms linked to each other to resemble collagen

BP determined by

cardiac output, blood volume, and resistance to flow - Blood volume regulated mainly by kidneys

Pressure point on the side of the neck

carotid

The binding of acetylcholine allows sodium gates to open, changing the inside of the cell to positive, which causes calcium ions enter the axon terminal. causes an action potential to propagate along the sarcolemma and down the T Tubules. causes synaptic vesicles to fuse to the membrane of axon terminal, allowing release of acetylcholine. causes an action potential to be initiated on the sarcolemma. causes calcium ions to be released from the terminal cisternae. acetylcholine to bind to receptor sites on the motor end plate.

causes an action potential to be initiated on the sarcolemma.

When enough positive ions enter the cell to bring the cell to threashold, this causes calcium ions enter the axon terminal. causes an action potential to propagate along the sarcolemma and down the T Tubules. causes synaptic vesicles to fuse to the membrane of axon terminal, allowing release of acetylcholine. causes an action potential to be initiated on the sarcolemma. causes calcium ions to be released from the terminal cisternae. acetylcholine to bind to receptor sites on the motor end plate.

causes an action potential to propagate along the sarcolemma and down the T Tubules.

myosin

changes shape during the contraction cycle

triads

characteristic feature of skeletal muscle, located at the A-I junction in mammalian tissue, each consists of narrow transverse tubule (T-tubule) between two terminal cisternae of sarcoplasmic reticulum

A muscle that is inserted on the mandible is probably involved in ____________. frowning chewing wrinkling the forehead kissing blowing

chewing

Hypotension

chronic low resting BP Caused by blood loss, dehydration, anemia

The anterior end of an earthworm is moved forward when: (p. 2)

circular muscles contract and longitudinal muscles relax.

circular

close body opening shy contracting

Diastole

complete relaxation of the ventricles

A muscle fiber exposed to a series of stimuli of increasing frequency combines individual twitches (summation) which results in

complete sustained contraction.

A condition in which stimuli occur so rapidly that there are no intervening relaxations between contractions is called

complete tetanus

A condition in which stimuli occur so rapidly that there are no intervening relaxations between contractions is called complete tetanus. incomplete tetanus. involuntary paralysis. all or none tetanus. treppe.

complete tetanus.

troponin

complex consisting of three subunits: TnC-binds calcium ions TnT-binds tropomyosin TnL-prevents the interaction between actin and myosin along with tropomysin involved in calcium regulation of contraction in striated muscle

thick myofilaments

composed of many myosin molecules arranged together to form a rod-like structure, measure 12 to 13 nm in diameter, 1.5 um in length, each myosin molecule appears similar to a double-headed golf club, with two globular projections, or heads, that possess a specific ATP-binding site, ATP hydrolysis occurs at the heads, also the location of the actin-binding site remain constant in length as the sarcomere shortens

T tubules provide nutrients to the muscle fiber. generate new muscle fibers. conduct action potentials deep into the muscle cell. release acetylcholine. store calcium ions.

conduct action potentials deep into the muscle cell.

the chief function of the T tubules is to

conduct the signal for contraction deeper into the muscle cell

Tendons:

connect a skeletal muscle to a bone.

I band and Z line contains what kind of protein?

connectin

myofibrils

consists of longitudinally arranged cylindrical bundles of thick and thin myofilaments, lie parallel to the long axis of cell and extend for its entire length, display crossbanding characteristic of striated muscle, held in alignment by intermediate filaments composed of the proteins desmin and vimentin, individually surrounded by the sarcoplasmic reticulum

cardiovascular system

consists of the heart and blood vessels has two major divisions: pulmonary circuit and systemic circuit

thin myofilaments

consists primarily of F actin, formed by polymerization of G (globular) actin monomers, 5 nm in diameter, 1.0 um in length, each actin filament consists of two such strands in the form of a double helix, troponins distributed along the thin filaments at 40-nm intervals, linear tropomyosin molecule lies within the groove of the actin double helix thin (actin) filaments and thick (myosin) filaments overlap for some distance within the A band

A proper definition of muscle tone is

constant tension produced by muscles for long periods of time.

A proper definition of muscle tone is constant tension produced by muscles for long periods of time. a feeling of well-being following exercise. the ability of a muscle to maintain a contraction against an outside force. muscles contracting together. warm-up of muscle tissue.

constant tension produced by muscles for long periods of time.

Muscle myofibrils are found in the sarcolemma. extend from the sarcolemma to the T-tubule. contain myosin and actin myofilaments. hold muscle cells together. do not appear striated.

contain myosin and actin myofilaments.

Actin myofilaments resemble bundles of minute golf clubs. contain both myosin and tropomyosin. are held in place by the M line. contain strands of fibrous actin. are the thickest proteins in muscle.

contain strands of fibrous actin.

sarcoma of neuromuscular junction

contains receptors for acetylcholine

axon terminal

contains vesicles filled with acetylcholine

Lack of acetylcholinesterase in the synaptic cleft would result in

continuous stimulation of the postsynaptic membrane.

Lack of acetylcholinesterase in the synaptic cleft would result in continuous stimulation of the postsynaptic membrane. decreased stimulation of the muscle. more acetylcholinesterase production. rapid degradation of acetylcholine.

continuous stimulation of the postsynaptic membrane.

Slow oxidative muscle fibers

contract slower but very hard to fatigue smaller axons bind to the muscle fibers but they are slower

myofibrils

contractile fibers within m. cells

All of the following terms refer to the ability to receive and respond to a stimulus, EXCEPT ___________. irritability contractility responsiveness excitability

contractility

isometric contraction

contraction of muscle during which the tension continues to increase but the muscle neither shortens nor lengthens

eccentric contraction

contraction of muscle in which the muscle contracts as it lengthens

concentric contraction

contraction of the muscle in which the muscle shortens and does work

Systole

contraction of the ventricles

Troponin pulls tropomyosin away from the binding sites on the actin filament. Myosin heads bind and sliding of filaments takes place using up ATP

contraction or sliding filament phase

What is a twitch?

contraction produced by one action potential

isotonic contraction

contraction with a change in length, but not in tension

A drug that interferes with the active transport of calcium ions from the sarcoplasm back into the sarcoplasmic reticulum would result in

contraction with no relaxation.

isometric contraction

contraction without a change in length

Muscle Twitch

contraction/relaxation of muscle fiber in response to a single action potential (stimulus)

Cardiac muscle contracts the heart. moves the skeletal system. controls the automatic movements in our bodies.

contracts the heart.

ACE inhibitor are used for

controlling high blood pressure treating heart failure preventing strokes and kidney damage in people with hypertension/diabetes

Smooth muscle contracts the heart. moves the skeletal system. controls the automatic movements in our bodies.

controls the automatic movements in our bodies.

Conduction system

coordinates heartbeat. stimulates contraction and relaxation of atria and ventricles throughout cardiac cycle. composed of internal pacemaker and nerve like conduction pathways through myocardium.

The muscle that adducts and flexes the arm is the

coracobrachialis.

What indirectly provides most of the energy for muscle contraction?

creatine phosphate

The relationship between ATP and creatine phosphate is that

creatine phosphate supplies energy to regenerate ATP from ADP and phosphate.

Myosin heads

cross bridges

Rigor mortis occurs after death because cross-bridges form but can't release. calcium is actively transported back to the sarcoplasmic reticulum. anaerobic respiration is occurring. myosin levels decline at death. cross-bridges never form.

cross-bridges form but can't release.

calmodulin

cytoplasmic, calcium-binding protein

If maximum tension indicates that the thick and thin filaments are set at optimal overlap to produce a maximum number of crossbridges, further stretching of the muscle will:

decrease the amount of thick and thin filament overlap.

Since the tension produced by a contracting muscle fiber depends upon the number of crossbridges between the thick and thin filaments, stretching the muscle beyond 28 mm:

decreases the amount of overlap and decreases the amount of tension produced by a single contraction

T-tubule

deep invagination of the sarcolemma (plasma membrane) into the muscle cell, rapidly conduct impulses from the exterior of the fiber to deeper regions, where they trigger release of calcium from the terminal cisternae, release of calcium into the myofibrils facilitates contraction

One of the key age related diseases facing the baby boomers generation is:

degeneration of bone integrity

a first degree block is caused by

delay of the action potential between the SA and AV nodes

cardiac cycle purpose

deliver adequate blood flow to pulmonary and systemic circulatory systems

The major abductor muscle of the upper arm is the ___________. coracobrachialis subscapularis supraspinatus teres major deltoid

deltoid

Which of the following is NOT a rotator cuff muscle? subscapularis infraspinatus deltoid teres minor

deltoid

abducts arm; anterior part flexes and rotates arm medially

deltoid

muscle name that describes shape

deltoid

the part of the neuron that normally receives stimuli is called what?

dendrite

fascia

dense CT that separates an ind skeletal muscle from adjacent muscles

Acetylcholine binds to a membrane bound receptor and causes ligand-gated sodium channels to open and results in

depolarization

P wave

depolarization in the atrial tissue - positive deflection

Phase 0

depolarization is primarily caused by increased Ca+ through the L-type Ca+ channels that began to open toward the end of Phase 4. The "funny" currents, and Ca+ currents through the T-type Ca++ channels, decline during this phase as their respective channels close. Because the movement of Ca+ through these channels into the cell is not rapid, the rate of depolarization (slope of Phase 0) is much slower than found in other cardiac cells

end plate potential

depolarization occurring only at neuromuscular junction

Acetylcholine binds to a membrane bound receptor and causes ligand-gated (that means CHEMICALLY GATED)sodium channels to open and results in depolarization. hyperpolarization. repolarization.

depolarization.

Isovolumetric contraction

depolarizing ventricles (QRS complex) and begin to contract, AV valves close, no ejection of blood yet

depresses lower lip

depressor labil inferioris

EKG are used to

diagnose heart abnormalities such as irregular heartbeat irregular speed of contractions, angina (chest pain that can indicate tissue damage or even tissue death( (myocardial infarction, also known as a heart attack)

What can influence Blood pressure

diet weight age genetics stress smoking alcohol physical activity drugs/medications

Pulse pressure

difference between systolic and diastolic pressure

Pulse pressure

difference between systolic and diastolic pressure Mean arterial pressure (MAP) - the mean pressure one would obtain by taking measurements at several intervals throughout the cardiac cycle - Diastolic pressure + (one-third of pulse pressure) - Average blood pressure that most influences risk level for edema, fainting (syncope), atherosclerosis, kidney failure, and aneurysm

Each cycle requires hydrolysis of one molecule of ATP and moves one actin filament 40nm. During contraction of a muscle sarcomere, a single actin filament moves 0.6μm. Calculate how many molecules of ATP are required to produce this movement. (2)

distance single actin filament moves divided by distance moved using 1 ATP; 15 ATP

What is the second step of muscle contraction?

due to the occurrences in the first step, action potential is triggered across the entire skeletal muscle membrane (sarcolema)

QT wave

duration of ventricular depolarization and repolarization

When are the AV valves open?

during atrial systole and ventricular diastole

Ventricular filling

during diastole, ventricles expand and pressure drops, AV valves open, blood flows into ventricles

When are the semi lunar valves closed

during the period of relaxation of the heart as a whole during atrial contraction

When are the AV valves closed

during ventricular systole

When are the AV valves closed?

during ventricular systole

When are the semilunar valves open?

during ventricular systole

myofibril

each m. fiber is composed of ____

active contraction of a muscle occurring simultaneously with lengthening of the muscle

eccentric contraction

second-class lever

effort applied at one end of the lever; the fulcrum located at the other; load between them

third-class lever

effort applied between the load and the fulcrum

first-class lever

effort is applied at one end of the lever; the load at the other; fulcrum somewhere in between

sarcoplasmic reticulum (smooth ER)

elaborate smooth endoplasmic reticulum tubules that run longitudinally a log the myofibrils and surround each myofibril

I band also contains?

elastic filaments

Which of the following allows recoil of the muscle fiber when contraction ends? actin elastic filaments myosin troponin tropomyosin

elastic filaments

fulcrum

elbow joint

electrodes of the EKG detect the

electrical current in the hearts' cells

__________ ___________ directs and choreographs the rhythmic beating of your heart

electrical energy

what is the heart beat caused by?

electrical impulses that control SA node

Purkinje fibers conduct

electrical signal to apex of heart and induce ventricles to contract at the same time to pump blood to out aorta to body and out pulmonary artery to the lungs

MI

elevated ST segment

Which of the following is equivalent to the ventricular volume during isovolumetric relaxation?

end systolic volume (ESV). Isovolumetric relaxation occurs at the beginning of ventricular diastole when the ventricular volume is at its minimum value−the end systolic volume (ESV). Because no volume changes occur during isovolumetric relaxation, ventricular volume remains at this value throughout the phase.

Each muscle fiber within a fascicle lies within a layer of connective tissue in the form of a thin covering called _______.

endomysium

Vertebrates are known to display which one of the following types of skeletons? (p. 1)

endoskeleton

terminal cisternae

enlarged areas of the sarcoplasmic reticulum surrounding the transverse tubules, discrete regions within the muscle cell, stores calcium (increasing the capacity of the sarcoplasmic reticulum to release calcium) and releases when an action potential courses down the transverse tubules-->elicit muscle contraction

An entire skeletal muscle is surrounded by ___________. epimysium perimysium endomysium. sarcolemma tendon sheath

epimysium

The dense layer of collagen fibers that surround an entire skeletal muscle is the ___________. fascicle tendon perimysium epimysium endomysium

epimysium

The layer of connective tissue that closely surrounds a skeletal muscle is called the ________.

epimysium

Which of the following connective tissue layers is outside all the others? perimysium endomysium epimysium paramysium sarcolemma

epimysium

the dense layer of collagen fibers that surround an entire skeletal muscle is the what?

epimysium

muscle potential causes Ca2+ gates to open on the sarcoplasmic reticulum, Ca2+ flows out and binds troponin

excitation-contraction coupling phase

Acetylcholine is released from the presynaptic terminal by the process of exocytosis. endocytosis. diffussion. active transport.

exocytosis.

perimysium

extends inward from epimysium and sep. m. into sm. sections. surrounds bundles of 10 - 100 ind. m. fibers. Sep. each muscle into fascles.

Damage to which of the following muscles would aid inspiration? sacrospinalis rectus abdominis platysma quadratus lumborum external intercostals

external intercostals

The muscular wall of the abdomen is composed of ____________. glossal muscles spinal erector muscles muscles of mastication digastric muscles external oblique and rectus muscles

external oblique and rectus muscles

a baseball player was hit on the left side of his head in the temporomandibular area. He cannot close his eyes and the corner of the mouth droops. Which cranial nerve was damaged?

facial

negative chronotropic agents

factors that lower the heart rate

A complete muscle contraction is called a muscle twitch.

false

A muscle that assists the muscle primarily responsible for a given action is called an agonist.

false

A short rest period after a muscle fiber experiences fatigue will allow that muscle fiber to contract again equally as long as it did before the fatigue.

false

Acetylcholine is actively transported from the pre-synaptic membrane to the post-synaptic membrane.

false

An example of a second-class lever is when you lift your head off your chest after a nap.

false

Calcium ion is released from the transverse tubule. True or False

false

During contraction, the actin myofilaments shorten.

false

If you bruised your gluteus maximus, you would expect to experience discomfort when flexing your leg.

false

In a relaxed muscle, the H zone is at its narrowest width.

false

In a relaxed muscle, the ends of the actin filaments overlap.

false

In fully contracted muscles, the actin filaments lie side-by-side.

false

Some muscles are named for the type of metabolism they generally use.

false

The anterior interventricular artery and the circumflex artery are the main branches of the right coronary artery. A) True B) False

false

The atria never need to contract due to passive ventricular filling. A) True B) False

false

The beginning of ventricular systole is when blood flowing back toward the relaxed ventricles causes the semilunar valves to close. A) True B) False

false

The binding of ATP immeditely initiates the sliding of muscle filaments past one another.

false

The degree of relative movement is greater in the pelvic girdle than in the pectoral girdle.

false

The end of a muscle that usually remains stationary when the muscle contracts is called the insertion.

false

The muscular arrangement that is the most advantageous when lifting a heavy load is parallel.

false

The pectoralis major originates on the scapula.

false

The pulmonary valve has string-like chordae tendineae and papillary muscles that prevent the valve cusps from prolapsing during right ventricular contraction. A) True B) False

false

The sternothyroid muscle originates on the hyoid bone.

false

The trapezius muscle is named for its location.

false

True or False Atrial contraction accounts for most of the ventricular filling.

false

True or False The atria never need to contract due to passive ventricular filling.

false

True or False The beginning of ventricular systole is when blood flowing back toward the relaxed ventricles causes the semilunar valves to close.

false

True or False: There is a minimum amount of mineral in bone necessary to maintain appropriate strength, but typically no upper limit on the amount of mineral that can be present. (p. 4)

false

cardiac muscle control is voluntary

false

cross bridge attachment to actin requires K+

false

cross bridges are formed by the actin molecules

false

in the initial stages of repolarization, the ionic conditions are restored, returning the membrane to its resting potential

false

muscles that exert very fine control (such as the muscles controlling movements of the fingers and eyes) have large motor units

false

one of the functions of the smooth muscle tissue is to force blood from the heart into the major arteries

false

subthreshold stimuli result in only a small amount of muscle response movement

false

the space between he neuron and the muscle is the axon terminal

false

the type of muscle fiber that is most resistant to fatigue is the fast fiber

false

In response to an action potential entering the neuron, calcium ions diffuse from the sarcolemma into the sarcoplasm. True or False

false Ca2+ diffuse from the sarcoplasmic reticulum into the sarcolasm

pennate

fascicles are short and attach obliquely to a central tendon that runs the length of the muscle; do NOT shorten as much but are more powerful

type of muscle fiber that responds quickly but also fatigues quickly

fast twitch fiber

tachycardia

faster than 100 beats per minute

Capillaries in the lungs

feed blood with carbon dioxide which makes it oxygen-rich and goes back to heart

Which of the following statements about smooth muscle is true? Nuclei are peripherally located in the fibers. Fibers are small and spindle-shaped. It has branching fibers. Smooth muscle is striated and involuntary. Contractions are rapid and forceful.

fibers are small and spindle-shaped

perimysium

fibrous connective tissue: the WHAT that bundles muscle fibers together in fasicles; collagent elastic fibers

epimysium

fibrous connective tissue: the WHAT that encloses the entire muscle; dense regular

the beginning o the muscle that typically does not move when a muscle contracts is called the

fibrous joint

everts foot; plantar flexes foot

fibularis (peroneus) longus and brevis

which type of lever is demonstrated by using scissors?

first-class lever

flexes wrist and abducts hand

flexar carpi ulnaris

example third-class lever

flexing the forearm with the biceps brachil

flexes wrist; aids abduction of hand

flexor carpi radialis

Which of the following adducts the fingers and wrist? extensor digitorum extensor carpi radialis longus flexor carpi ulnaris flexor carpi radialis

flexor carpi ulnaris

flexes the four fingers and wrist

flexor digitorium superficialis

flexes fingers and assists in flexing wrist

flexor digitorum profundus

Blood supply to a tissue can be expressed in terms of ______ and ________

flow and perfusion

periaxial space

fluid-filled cavity that exists between the connective tissue capsule and intrafusal fibers

Reduced blood pressure makes it easier

for the heart to pump blood`

One ATP molecule is required for

formation of the cross-bridge, for movement of the cross-bridge, and for release of the cross-bridge.

Systemic Circulation

from heart to body (oxygenated blood) Superior vena cava Tissue capillaries Left ventricle Left atrium Inferior vena cava leaves heart oxygenated returns to heart deoxygenated (body tissues received the oxygen which makes them stay alive)

What happens to H zone during sarcomere contraction?

gets shorter

What happens to I band during sarcomere contraction?

gets shorter

Actin

globular actin naturally polymerizes into fibers in the presence of Mg and ATP the functional unit of the think filament is composed of two strand of F-actin that forms a double stranded alpha helix-looks like DNA but uses actin molecules instead of nucleotides bases.

"Cross bridges" that link between the thick and thin filaments are formed by the ___________. tails of myosin filaments globular head of thick filaments globular actin F actin

globular head of thick filaments

extends and laterally rotates thigh; extends hip against resistance

gluteous maximus

muscle name that describes size

gluteus maximus

A gluteal gait, in which a person walks with a waddling limp, is usually caused by a disorder of the

gluteus medius and gluteus minimus.

an anaerobic metabolic pathway that results in the product of two net ATP's per glucose plus two pyretic acid molecules is what?

glycolysis

abducts thigh; flexes and medially rotates leg

gracilis

flexes leg and rotates it medially; abducts thigh

gracilis

Pacemaker Potential

gradual depolarization, SA node resting potential start at -60mV and then drifts spontaneously upwards

electrocardiogram

graph that monitors and records electrical activity abbreviated as EKG and ECG

During the ventricular ejection phase of the cardiac cycle, which of the following is true?

he semilunar valves are open.. During ventricular ejection, blood flows from the ventricles into the arteries. To do so, the blood must pass through the semilunar valves, which must be open during this phase. Narrowing of the left semilunar valve reduces blood flow out of the heart, a disease condition known as aortic stenosis.

Hypertension

high blood pressure - Chronic resting BP > 140/90 - Consequences • Can weaken arteries, cause aneurysms, promote atherosclerosis

Hypertension

high blood pressure Chronic resting BP > 140/90 Consequences: Can weaken arteries, cause aneurysms, promote atherosclerosis

In Anna's cardiac workup Anna had

high blood pressure her values averaged 142/85

Tetanus of a muscle is thought to be caused by

high calcium ion concentrations in the sarcoplasm.

systolic pressure

high pressure measured on artery wall when heart ventricles contract

creatine phosphate

high-energy compound in muscle

Contractility

how hard the myocardium contracts for a given preload • Positive inotropic agents increase contractility • Negative inotropic agents reduce contractility

The _______ nerve innervates all of the extrinsic tongue muscles. vagus hypoglossal facial trigeminal

hypoglossal

The prime mover for flexion of the thigh is the __________ muscle. sartorius iliopsoas quadratus lumborum psoas minor

iliopsoas

Paralysis of which of the following would make an individual unable to flex the thigh?

iliopsoas and rectus femoris

Which of the following statements is true concerning calcium ions?

in smooth muscle it binds with calmodulin.

where is the SA node located

in the right atrium

relaxed

in this state, actin and myosin myofilaments lie side by side and the H zones and I band are at a max. width.

where is blood pressure taken

in upper arm on level with the heart over an artery in joint

AV node (atrioventrical node) is located

in wall between right atrium and right ventricle

Curare blocks acetylcholine receptors at the motor end plate. This would result in inability of the muscle fiber to respond to nervous stimulation. increased stimulation of the muscle. more acetylcholinesterase production. sustained contraction of the muscle.

inability of the muscle fiber to respond to nervous stimulation.

If the amount of tension produced by the muscle depends upon the number of crossbridges, according to your data the number of crossbridges:

increase as the muscle was lengthened to about 28 mm.

Initially, you applied a shock to the shortened muscle and measured the tension. You then stretched the muscle and repeated the experiment. After repeating the amount of tension:

increase as the muscle was stretched to about 28 mm

Positive inotropic agents

increase contractility

Sympathetic nerves

increase heart rate and contraction strength - Sympathetic pathway to heart originates in the lower cervical to upper thoracic segments of the spinal cord

A child ingested an organophosphate poison used to kill insects. Soon the child's muscles began tetanic contractions. Predict what occurred at the synaptic cleft. increased accumulation of acetylcholine in the synapse increased release of acetylcholine from presynaptic neurons the poison binds to acetycholine receptors and stimulates them increased breakdown of acetylcholine in the synaptic cleft.

increased accumulation of acetylcholine in the synapse

Which of the following helps explain the increased tension seen in multiple wave summation? increased motor unit recruitment increased concentration of calcium ions around the myofibrils exposure of more active sites on myosin myofilaments the breakdown of elastic elements in the cell decreased stimulus frequency

increased concentration of calcium ions around the myofibrils

The sequence for smooth muscle contraction is...

increased cytosolic calcium, which binds to calmodulin in cytosol, complex binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin cross-bridges, which bind to actin filaments, resulting in contraction.

The sequence for smooth muscle contraction is...

increased cytosolic calcium, which binds to calmodulin in cytosol, complex binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin cross bridges, which bind to actin filaments, resulting in contraction.

The sequence for smooth muscle contraction is...

increased cytosolic calcium, which binds to calmodulin in cytosol, complex binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin cross-bridges, which bind to actin filaments, resulting in contraction.

The sequence for skeletal muscle contraction is...

increased cytosolic calcium, which binds to troponin, which moves tropomyosin from blocking active sites on actin filament, which binds with myosin cross bridges, resulting in contraction.

The sequence for skeletal muscle contraction is...

increased cytosolic calcium, which binds to troponin, which moves tropomyosin from blocking active sites on actin filament, which binds with myosin cross-bridges, resulting in contraction.

The duration of the latency period:

increases with weight.

What are multiunit summation or recruitment?

increasing the number of motor units contracting at the same time. Generally, the samller motor units which are more sensitive are activated first, followed by progressively larger motor units. Activation of more motor units will increase the greater the number of cross bridges formed and therefore produce more tension.

What are spatial or temporal wave summations?

increasing the number of stimuli delivered to a given motor unit per time. Results in increased Ca concentration which then causes more tension/shortening. Activation of more cross bridges per period of time will generate more tension per time.

fibromyositis

inflammation of a muscle, its connective tissue coverings and tendons, and capsules of nearby joints

Shin splints are caused by __________. rupturing of the calcaneal tendon tearing of the hamstring muscles inflammation of the tibialis anterior inflammation of the gastrocnemius

inflammation of the tibialis anterior

skeletal/cardiac muscle contraction

initiated by the binding of Ca2+ to the TnC unit of troponin, exposes the myosin binding site on actin (cross-hatched area), myosin head binds to actin, ATP breaks down into ADP-->energy, produces movement of the myosin head-->bound thin filaments slide over the thick filaments, process repeats many times during a single contraction, leads to a complete overlapping of the actin and myosin and a resultant shortening of the whole muscle fiber

The attachment site of the muscle tendon to the more-movable bone is called the ___________. proximal end distal end origin belly insertion

insertion

Where would you expect to find numerous gap junctions in muscular tissue?

intercalated discs of cardiac muscle

The structures that connect cardiac muscle cells are

intercalated discs.

the force generated during this time is called ______ tension

internal

In the neuromuscular junction, acetylcholine:

is actively transported across the synaptic cleft and binds to acetylcholine receptors on the postsynaptic muscle fiber.

Treppe can contribute to improved muscle efficiency. may be due to an increase in the level of calcium ions around the myofibril. is an example of a graded response. is achieved during warm-up exercises. is all of the above.

is all of the above.

A fasciculus is a bundle of reticular fibers. is surrounded by perimysium. is only found in smooth muscle. possesses an external lamina. is a bundle of collagen fibers.

is surrounded by perimysium.

incomplete tetanus

is the condition in which the muscle fiber only partially relaxes between contractions.

the refractory period

is the time during which the tissue cannot respond again.

Smooth muscle is under involuntary control. is under voluntary control.

is under involuntary control.

Skeletal muscle is under involuntary control. is under voluntary control.

is under voluntary control.

The type of muscle contraction in which the muscle fibers produce increased tension, but the muscle neither shortens nor lengthens, is called _____________. treppe isotonic isometric concentric tetany

isometric

muscle is under tension (contracting but no noticeable movement is noted)

isometric contraction

muscle shortens during contraction

isotonic contraction

Phases of the Cardiac Cycle stages

isovolumetric contraction ventricular ejection isovolumetric relaxation

The steps of the cardiac cycle in sequence are...

isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling.

Which of the following is NOT a characteristic of skeletal muscle contraction? It is voluntary. It contracts rapidly. It can exert tremendous power. It can contract for long periods of time without tiring.

it can contract for long periods of time without tiring

What happens to the H band during muscle relaxation?

it lengthens

What happens to the I band during muscle relaxation?

it lengthens

What happens to the sarcomere during muscle relaxation?

it lengthens

What happens to the A band during muscle contraction?

it stays the same

The chordae tendineae

keep the AV valves from everting during ventricular systole

Which of the following substances increases in quantity during repetitive muscle contraction during oxygen deficit? adenosine triphosphate (ATP) glucose lactic acid oxygen creatine phosphate

lactic acid

The concentric rings of bone produced are...

lamellae

How many proteins does the thick filament have once made

largest subunit-heavy chain-so myosin is the heavy chain, ELC and RLC are the light chains, the total complex is considered a hexamere-6 proteins, or 2 trimers These hexameric myosin complex then further assemble into a much larger thick filament the thick filament is a bi polar structure growing out form a core

The time between application of the stimulus to a motor neuron and the beginning of contraction is called the _____ phase. contraction relaxation latent or lag refractory threshold

latent or lag

the short delay between the stimulus and the onset of the twitch is called the?

latent period

In a recording of a muscle twitch, the delay between the time a stimulus is applied and the time the muscle responds is called the

latent period.

protracts mandible and moves side to side

lateral pterygoid

extends, abducts, and rotates arm medially

latissimus dorsi

mitral regurgitation

leaky valve sometimes called a heart murmur

Systemic Circuit

left side of the heart, carries blood to body (all tissues), carries oxygen RICH blood.

The force of contraction is lowest for a muscle fiber...

less than 100% of its relaxed length., greater than 100% of its relaxed length.

I band

light area of a sarcomere. only actin

2nd degree Heart Block Type 1

long PR, longer PR, then P and no R complex, AV node dx - electrical impulses are delayed more and more until a beat is skipped/dropped

The monosyllables describing the heart sounds are

lub - dup

Which of the following muscles of the face is NOT innervated by the facial nerve? zygomaticus orbicularis oculi masseter mentalis

masseter

smooth muscle contraction

may be initiated by nerve impulses, stretching within the muscle itself or via hormones vascular smooth muscle contraction usually initiated by nerve impulse, there is little spread of conduction from cell to cell visceral smooth muscle contraction is myogenic (stretch) and signal spreads from cell to cell via gap junctions in uterus, during terminal stages of pregnancy, smooth muscle cells contract in response to oxytocin elsewhere in body smooth muscle cells responsive only to epinephrine smooth muscle cells lack troponin but require calcium for their contractile activity, calcium activate enzyme which phosphorylates light chain of myosin allowing myosin to bind to actin and hydrolyze ATP

Fibers of muscles whose motor neurons are severed

may be replaced by fat or fibrous connective tissue.

when one-third of the pulse pressure is added to the diastolic pressure a good estimate of the ___________ is obtained

mean arterial pressure

elevates mandible and moves side to side

medial pterygoid

diastolic pressure

minimum arterial BP taken during ventricular relaxation (diastole) between heart beats

Threshold stimulus is the

minimum strength of stimulation required to contract a muscle fiber

blood pressure in measured in

mm of mercury (Hg) the measurement of force/pressure that supports a column of mercury that many mm high

What category below do snails best fit into?

mollusks

What event results in dicrotic notch

momentary increase in aortic pressure that occurs when the semi lunar valves snap shut

during exercise the skeletal muscles receive ______ blood flow

more

The outside of the resting plasma membrane is __________ relative to the inside of the resting plasma membrane. more postively charged. more negatively charged. neutral. recharged.

more postively charged.

Depolarization occurs because

more sodium ions diffuse into the cell than potassium ions diffuse out of it.

The chemicals then bind to receptors located on the _____ ______ ______, a specialized area of the sarcolemma.

motor end plate

At a neuromuscular junction, the muscle fiber membrane folds, forming a

motor end plate.

Acetylcholine is the neurotransmitter at neuromuscular junctions. Describe how the release of acetylcholine into a neuromuscular junction causes the cell membrane of a muscle fibre to depolarise. (3)

movement of acetylcholine by diffusion; binding to receptors on post-synaptic membrane; causing sodium channels to open

Which of the following actions is caused by contraction of skeletal muscle? contraction of the heart moving your feet in walking movement of food through the G.I. tract emptying of the urinary bladder vasoconstriction

moving your feet in walking

ball and socket joint

moving your leg at the hip

leaky heart valve causes

murmur

What is a sarcomere contraction?

muscle cells shorten becasue their individual sarcomeres shorten

sarcomeres

muscle fibers (myofibrils) are collections of these. p. 287

A weightlifter uses muscles so the muscles exert more than 75% of their maximum tension, This stimulates

muscle fibers developing new filaments of actin and myosin.

myalgia

muscle pain resulting from any muscle disorder

An example of a partial but sustained contraction is

muscle tone.

flexors

muscles that bend a limb at a joint

extensors

muscles that straighten a limb

Which of the following is thought to be an autoimmune disease of acetylcholine receptors? fibromyalgia myotonic dystrophy muscular dysthrophy myasthenia gravis

myasthenia gravis

Which one of the following is most accurately referred to as an autoimmune disease? (p. 17)

myasthenia gravis

A sarcomere is part of a(n) ___________. perimysium myofibril myofilament endomysium

myofibril

The names of the muscles can indicate all of the following, EXCEPT ___________. the region of the body where the muscle is located the direction of the muscle relative to the long axis of the body myofibril composition of the muscle structural characteristics of the muscle action of the muscle

myofibril composition of the muscle

Figure 2 shows the cut ends of the protein filaments when the myofibril was cut at position Y. Figure 3 shows the protein filaments when the myofibril was cut at the same distance from a Z line at a different stage of contraction. Explain why the pattern of protein filaments differs in Figure 2 and Figure 3. (2)

myofibril is contracting in Figure 3 and relaxing in Figure 2; figure 3 shows movement of actin fibres between myosin fibres

Arrange the following structures from smallest to largest. (p. 5)

myofibril, muscle fiber, muscle bundle, muscle

one of the slender threads of a muscle fiber, composed of numerous myofilaments; composed of repeating units of sarcomeres

myofibrils

During muscle contraction ATP supplies energy for

myofilament movement.

In the sliding filament model of muscle contraction, the myofilaments slide over each other, resulting in the overlapping of actin and _________. myosin thin filaments troponin actin tropomyosin

myosin

Which of the following is the site of ATP binding and hydrolysis?

myosin

a fibrous protein that attaches to actin through head like structures; it is the contractile filament of muscle cells

myosin

In order for muscle contraction to occur, cross-bridges form between:

myosin and actin.

Which of the following is not a part of the relaxation phase of a muscle twitch? muscle to return to its original length cross bridge cycling decreases and end calcium ions are actively transported back into the terminal cisternae myosin cross bridge cycling causes sarcomeres to shorten

myosin cross bridge cycling causes sarcomeres to shorten

As actin and myosin filaments slide past each other during muscle contraction:

myosin filaments shorten, while actin filaments do not.

During muscle contractions, cross-bridges form between

myosin heads and actin filaments

What is the fourth step of muscle contraction?

myosin heads bind to the binding sites exposed by the displacement of trypmyosin and pull actin toward the midline, shortening the sarcomere

ATPase is found in F-actin strands. G-actin globular units. myosin heads. tropomyosin grooves. troponin molecules.

myosin heads.

During muscle contractions, cross-bridges form between the _________ and the __________.

myosin heads; actin filaments

Which of the following is mismatched? I band - contains only actin M line - middle of the H zone Z disk - structure between adjacent sarcomeres myosin myofilaments - thin myofilaments actin myofilaments - thin myofilaments

myosin myofilaments - thin myofilaments

I band

narrows during muscle contraction

Is a polarized membrane more positive or negative?

negative

As actin and myosin filaments slide past each other during muscle contraction,

neither actin nor myosin filaments shorten.

Which of the following happens as actin and myosin filaments slide past each other during muscle contraction?

neither action or myosin shorten

myoneural junction (motor end plate)

nerve terminal, contains many mitochondria and small vesicles (storage sites of the neurotransmitter acetycholine)

Purkinje fibers

nervelike processes that arise from the lower end of the bundle branches and turn upward to spread through the ventricular myocardium. Purkinje fibers distribute the electrical excitation to the cardiocytes of ventricles. they form a more elaborate network in the left ventricle than in the right.

The neuron releases acetyl choline causing a muscle potential to run down the innervated muscle cell

neural excitation phase

Each skeletal muscle fiber is controlled by a neuron at a single ___________. synaptic cleft transverse tubule sarcomere synaptic knob neuromuscular junction

neuromuscular junction

area on the surface of a muscle cell where the axon foot of the nerve meets the muscle cell it will stimulate

neuromuscular junction

The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called neuromuscular junctions. sarcomeres. myofilaments. Z disks.

neuromuscular junctions.

acetylcholine

neurotransmitter at the neuromuscular junction

acetylcholine

neurotransmitter released into the neuromuscular junction

What part of the muscle does the chemical, released by the nerve, act on?

nicotinic protein channel receptor

After death, cross bridges between actin and myosin remain firmly bound resulting in rigor mortis. Using information in the diagram, explain what causes the cross bridges to remain firmly bound. (2)

no ATP produced; ATP required for separation of actin and myosin

H band is what kind of filament?

none, lighter color

smooth muscle

nonstriated, involuntary, found on the wall of hollow organs and tracts

Sinus rhythm

normal heartbeat triggered by the SA node - Adult at rest is typically 70 to 80 bpm (vagal tone)

Isovolumetric contraction of ventricles

occurs after the ventricles depolarize. The AV valves close as ventricular blood surges back against the cusps. Ventricles do not yet eject blood and there is no change in their volume even though they are contracting

A sarcomere extends from one Z disk to an adjacent Z disk. one T tubule to the next T tubule. the middle of the I band to the middle of the A band. the H zone to the I band. M line to the next M line.

one Z disk to an adjacent Z disk.

Cardiac cycle

one complete heartbeat, both atria and ventricles contract and relax

sphincter muscles of the eyelids; permits squinting and blinking

orbicularis oculi

Bone producing cells are...

osteoblasts

The combination of all of the concentric rings of bone built around a single blood vessel is called a(n)...

osteon.

epimysium

outermost layer. encircling the whole muscle.

electrical conditions of a resting sarcolemma

outside positive relative to the inside

tropomyosin

overs thin filament-binding areas

myoglobin

oxygen storage molecules in skeletal muscle

The extensor digitorum muscle is an example of a ____________ muscle. fusiform muscle convergent circular pennate

pennate

Another layer of connective tissue, called the _______, extends inward from the epimysium and separates the muscle tissue into small sections. These sections contain bundles of skeletal muscle fibers called _______.

perimysium; fascicles

bradycardia

persistent resting adult heart rate below 60 bpm. common in endurance trained athletes, in rest/sleep. endurance training enlarges the heart and increases stroke volume, enabling it to maintain same output with fewer beats

tachycardia

persisting resting adult heart rate above 100 bpm causes: stress, anxiety, stimulants, heart disease, fever heart rate rises to compensate for drop in stroke volume; heart races when body loses significant quantity of blood/when there's damage to myocardium

What is the role of phosphocreatine in the muscle cell?

phosphocreatine rapidly creates ATP by phosphorylating ADP in the cell

sarcolemma

plasma membrane of skeletal muscle fiber

S-T segment

plateau phase, ventricular systole

Each of the following terms is used to describe the shape of a muscle, EXCEPT ____________. piriformis pollicis trapezius rhomboid quadratus

pollicis

Is a depolarized membrane more positive or negative?

positive

Which of the following statements describe histological characteristics of skeletal muscle? presence of visible striations & single, centrally-located nuclei presence of visible striations & multiple peripheral nuclei absence of visible striations & single, centrally-located nuclei number of nuclei

presence of visible striations & multiple peripheral nuclei

Which of the following statements describe histological characteristics of cardiac muscle? presence of visible striations & single, centrally-located nuclei presence of visible striations & multiple peripheral nuclei absence of visible striations & single, centrally-located nuclei number of nuclei

presence of visible striations & single, centrally-located nuclei

What can high blood pressure cause

pressure can cause damage to blood vessels which bleed and clot vessels damaged areas are more likely to accumulate plaque a substance which contains cholesterol

Blood pressure

pressure exerted by blood against the walls of blood vessels

hydrostatic pressure

pressure exerted on the wall of the of the "pipe" or "hose" as fluids move through them

blood pressure

pressure on the walls when blood moves through the blood vessels

Athletes usually experience muscle fatigue less quickly than nonathletes because they

produce less lactic acid.

pronates forearm and hand

pronator quadratus

pronates forearm and is a flexor of the elbow

pronator teres

action potential

propagation of an electrical current along the sarcolemma

Sliding Filament Hypothesis (of Huxley)

proposes that during muscle contraction, filaments themselves do not change in length but slide past one another to increase the amount of overlap between them, sliding action results from repeated "make and break" attachments between the heads of the myosin molecules and neighboring actin filaments-->length of the sarcomere shortened in contraction, thin filaments slide to penetrate more deeply into the A band, A band remains constant in length, I band and H band both decreases in size, Z lines drawn closer to the ends of the A bands

rotates thigh laterally; stabilizes hip joint

quatratus femoris

Fast oxidative/glycolytic

quick contracting, a little resistant to fatigue but fatigue in bigger motor neuron coming to it

Fast glycolytic

quick contracting-fatigue easily in biggest motor neuron

Pressure point of the wrist

radial

lever

radius

extends leg at knee and flexes thigh at hip

rectus femoris

blood flow is _____ to meet metabolic needs

redirected

Negative inotropic agents

reduce contractility

Hypercalcemia

reduces heart rate - high Ca+

A person continues breathing heavily for some time after exercising in order to repay an oxygen "debt". This oxygen debt allows for which of the following to occur:

replenish oxygen stored in the myoglobin of the muscle cell

The refractory period in which the muscle will NOT contract if stimulated occurs during __________ of the muscle cell. repolarization polarization depolarization hyperpolarization

repolarization

Phase 3

restoring of the potential by Na+ (moving out), K+ (moving in) and Ca+ (moving out). Pumps ATP driven.

Multiple wave summation

results in complete and incomplete tetanus.

stabalizes, retracts, and rotates the scapula

rhomboids (major and minor)

What triggers action potentials in cardiac muscle?

rhythmic depolarizations due to pacemaker channels in the plasma membrane

For animals of an equal body weight, which one of the following types of movements has the highest energy cost? (p. 15)

running

Where is Titin found?

runs through core of each thick filament

The discoloration and swelling of a muscle strain is due to

ruptured blood vessels

the cell membrane of skeletal muscle is called the

sarcolemma

the membrane covering a striated muscle fiber

sarcolemma

T tubules are invaginations of the sarcoplasmic reticulum. sarcomere. myofibril. sarcoplasm. sarcolemma.

sarcolemma.

The distance from one Z disk to the next Z disk is called a(n)

sarcomere

The distance from one Z disk to the next Z disk is called a(n)...

sarcomere

The functional unit of contraction in a skeletal muscle fiber is the ____________. sarcoplasmic reticulum sarcolemma sarcomere myofibril myofilament

sarcomere

the functional unit of a skeletal muscle fiber is the

sarcomere

The striated appearance of skeletal muscle fibers results from the

sarcomere organization.

Muscle fibers are basically a collection of

sarcomeres

calsequestrin

sarcoplasmic protein, binds calcium in absence of excitation and contraction, located in dilated terminal cisternae of sarcoplasmic reticulum, this assures proximity of calcium to transverse tubules which carry excitation wave deep in muscle cell

Calcium for muscle contraction is stored in the

sarcoplasmic reticulum

a system of membrane-bound tubules that surrounds muscle fibrils, releasing calcium ions during contraction

sarcoplasmic reticulum

the series of membraneous channels that surround each myofibril is what?

sarcoplasmic reticulum

An action potential causes calcium ions to diffuse from the ________ into the ________.

sarcoplasmic reticulum ------ sarcoplasm

An action potential causes calcium ions to diffuse from the ________ into the ________.

sarcoplasmic reticulum ; sarcoplasm

An action potential causes calcium ions to diffuse from the ________ into the ________.

sarcoplasmic reticulum; sarcoplasm

An action potential causes calcium ions to diffuse from the ________ into the ________. sarcoplasmic reticulum; sarcolemma sarcoplasmic reticulum; sarcoplasm sarcoplasm; sarcoplasmic reticulum sarcoplasm; sarcolemma sarcolemma; sarcoplasm

sarcoplasmic reticulum; sarcoplasm

An electrical impulse traveling along the sarcolemma and into transverse tubules causes calcium ions to diffuse from the ________ into the ________.

sarcoplasmic reticulum; sarcoplasm

The obturator nerve supplies all of the following muscles, EXCEPT the ____________. adductor brevis sartorius adductor magnus gracilis

sartorius

flexes, abducts, and laterally rotates thigh

sartorius

muscles on the side of the neck located deep to platysma and sternocleidomastoid

scalenus

The second heart sound is a result of the closure of the

semi lunar valves

composite muscle located along the back from thoracic region to head

semispinalis capitis, cervicis, and thoracis

muscle spindle (neuromuscular spindle)

sensory organ in skeletal muscle that functions as stretch receptor, participate in nervous control of body posture and coordinate action of opposing muscles, receives large afferent sensory nerve fiber with several types of nerve endings: annulospiral endings (wind around intrafusal fibers), flower spray endings (terminates in clusters), y-efferents, or fusimotor endings (form motor endplates near the poles of the spindle) appears as elongated fusiform encapsulated structure that contains several modified striated muscle fibers (intrafusal fibers) and associated nerve endings two types of intrafusal fibers: nuclear bag fibers with cluster of nuclei in nonstriated region that produce slight expansion in area thin nuclear chain fibers most common, nuclei arranged in a row

proprioceptors

signal cardiac center (beginning of exercise, signals from joints and muscles reach the cardiac center of brain) sympathetic output from cardiac center increases cardiac output

In the heart, an action potential originates in the __________.

sinoatrial node The normal heartbeat is triggered by autorhythmic cells in the right atrium called the sinoatrial node.

Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the

size of muscle fibers

muscle cell regeneration

skeletal muscle has population of undifferentiated cells (satellite cells)-->have the ability to replace some cells lost by trauma and injury cardiac muscle cannot regenerate, when injured cells die and are replaced by scar tissue pericytes are stem cells of smooth muscle and are capable of regenerating small blood vessels that consist of smooth muscle, bladder and intestines are also capable of undergoing regeneration of smooth muscle

actin

slides toward the M line during contraction

Parasympathetic nerves

slow heart rate - Pathway begins with nuclei of the vagus nerves in the medulla oblongata - Extend to cardiac plexus and continue to the heart by way of the cardiac nerves

type of muscle fiber that have fatigue resistance and high oxidative/aerobic capacity

slow twitch fiber

Pacemaker cells - SA node - depolarizing current is carried by what currents?

slow, inward Ca++ currents. Unlike most other cells, there are no fast Na+ currents operating in SA nodal cells

First degree Heart Block

slowing conduction in AV node, PR interval is longer

Which type of muscle does not have a transverse tubule system or a well-developed sarcoplasmic reticulum?

smooth muscle

Both acetylcholine and norepinephrine can affect (which muscle)

smooth muscle contraction

Both acetylcholine and norepinephrine can affect

smooth muscle contraction.

Short muscle cells with centrally located nuclei are

smooth muscle fibers.

Which causes:

sodium ions to diffuse through and enter the cell.

Depolarization of the cell membrane occurs when there is a rapid influx (inflow) of sodium ions. calcium ions. potassium ions. chloride ions.

sodium ions.

plantar flexes foot; important in posture

soleus

synaptic cleft

space between the neuron and and the muscle membrane

purkinje fibers

specialized conducting cells of atrioventricular bundle, very large modified muscle cells filled with glycogen and contain many mitochondria, contain few myofibrils which are located peripherally, make contact with cardiac muscle cells through gap junctions, desmosomes and fasciae adherentes (not through typical intercalated disks)

motor nerve ending

specialized region on the skeletal muscle fiber (cell) where a motor nerve terminates, as axon approaches muscle cell it loses its myelin sheath, Schwann cell continues to cover the nonsynaptic surface of the nerve terminal, nerve terminal lies in indentation (primary synaptic cleft) of the skeletal muscle fiber, additional invaginations of the sarcoplemma lining the primary synaptic cleft form junctional folds (secondary synaptic clefts)

AV node delays

spreading the electrical impulses for 0.1 secs to ensure the atria are completely empty

example second-class lever

standing on tip-toe

flexes and laterally rotates the head

sternocleidomastoid

Arteriosclerosis

stiffening of arteries due to deterioration of elastic tissues of artery walls

parallel

strap like with an extended belly; great ability to shorten but not usually very powerful

Smooth muscles lack ______ and contain less _________

striations; myosin

chief medial rotator of arm

subscapularis

Afterload

sum of all forces opposing ejection of blood from ventricle. Anything that impedes arterial circulation can also increase afterload - Lung diseases that restrict pulmonary circulation - Cor pulmonale: right ventricular failure due to obstructed pulmonary circulation • Largest part of afterload is blood pressure in aorta and pulmonary trunk - Opposes the opening of semilunar valves - Limits stroke volume • Hypertension increases afterload and opposes ventricular ejection

Order of blood flow through heart

superior/inferior vena cavas - to right atrium - through tricuspid (atrioventricular) valve - to right ventricle - through pulmonary valve - to pulmonary arteries - to the lungs. Then it returns through pulmonary vein - to the L atrium - through the mitral (bicuspid) valve - to the L ventricle - through the aortic valve - into the aorta and rest of the body

perimysium

surrounds each muscle bundle (fascicle)

endomysium

surrounds each muscle fiber

Endomysium is a delicate network of loose connective tissue that surrounds each muscle fiber. forms a sheath around a fasciculus. is composed of elastic fibers. separates individual muscles. penetrates muscle fibers.

surrounds each muscle fiber.

epimysium

surrounds entire muscle

endomysium

surrounds individual muscle fibers

cramp

sustained spasm, or tetanic contraction

Which of the following is not considered a weight bearing activity?

swimming

The functional connection between a neuron and a skeletal muscle fiber is a

synapse

The site where the neuron communicates with the muscle fiber is called a ________.

synapse

The space between the neuron and the muscle is the ___________. synaptic knob motor unit motor end plate synaptic cleft M line

synaptic cleft

These chemicals diffuse across a small gap between the neuron and muscle fiber called the _______ _______.

synaptic cleft

the space between the neuron and the muscle is the what?

synaptic cleft

The attachment of calcium to the syptic vesicles causes the calcium ions enter the axon terminal. action potential to propagate along the sarcolemma and down the T Tubules. synaptic vesicles to fuse to the membrane of axon terminal, allowing release of acetylcholine. action potential to be initiated on the sarcolemma. Calcium ions to be released from the terminal cisternae. acetylcholine to bind to receptor sites on the motor end plate.

synaptic vesicles to fuse to the membrane of axon terminal, allowing release of acetylcholine.

A muscle that assists the agonist is a(n)

synergist

A muscle that assists the muscle primarily responsible for a given action is a(n) __________. levator primary antagonist originator synergist antagonist

synergist

a muscle that assists the muscle that is primarily responsible for a given action is a(n)

synergist

muscles that help the prime mover my interacting at the same time to assist in the movement so that the movement is more effective

synergists

pulse pressure

systolic pressure minus diastolic pressure, indicates actual working pressure

In Anna's cardiac workup anna was

tachycardic her heart rate was 90-105

muscle name that describes location

temporalis

this is the time required for the excitation and ________ of the elastic components of the muscle

tensing

once elastic components are taut, the muscle produces external ________

tension

in an isotonic contraction

tension rises and the skeletal muscle length changes

Smooth muscle generates less __________ but can contract over a ____________ range of lengths

tension; greater

Which of the following best describes the composition of the structure known as a triad in a skeletal muscle fiber? sarcolemma, sarcoplasm, and sarcoplasmic reticulum terminal cisterna, transverse tubule, and terminal cistern actin, troponin, and tropomyosin ATP, CP, and glycogen A band, I band, and H band

terminal cisterna, transverse tubule, and terminal cistern

electrical impulses travel through cardiac cells and cardiac muslce tissue to

the AV node

What do H zones and I bands contain?

the H zone contain only myosin and the I band only contain actin

Which of the following statements about H zones and I bands is TRUE?

the H zones contain only myosin, while the I bands contain only actin

An action potential enters the depths of a muscle fiber by way of __________. diffusion the T tubules the calcium ion channels the sarcoplasmic reticulum the actin myofilament

the T tubules

H

the ____ zone contains only myosin and is in the center of the sarcomere

calcium, troponin

the _____ ion binds with the protein _____ during m. contraction

Which of the following characteristics is unique to smooth muscle? hyperplasia the ability of ATP to energize the sliding process response to stretch the absence of striations

the absence of striations

Cross bridges form between _________________.

the actin filaments and the myosin heads

Cross bridges form between...

the actin filaments and the myosin heads.

Blood flow

the amount of blood flowing through an organ, tissue, or blood vessel in a given time (mL/min.)

preload

the amount of tension in ventricular myocardium immediately before it begins to contract - Increased preload causes increased force of contraction - Exercise increases venous return and stretches myocardium - Cardiocytes generate more tension during contraction - Increased cardiac output matches increased venous return • Frank-Starling law of the heart: SV ∝ EDV - Stroke vol. is proportional to the end diastolic volume - Ventricles eject almost as much blood as they receive - The more they are stretched, the harder they contract - Relates to length-tension relationship of striated muscle

AV node

the atrioventricular node is located at lower end of the interatrial septum near right AV valve. -acts as an electrical gateway to the ventricles -the fibrous skeleton acts as an insulator to prevent currents from getting to the ventricles by any other route.

When the pressure in the ventricles becomes lower than the pressure in the atria...

the atrioventricular valves open.

Ventricular systole causes

the atrioventricular valves to close, and then the semilunar valves to open.

z line

the border of a sarcomere. where actin is anchored by titin

sarcolemma

the cell membrane of a muscle fiber

M line

the center of the A band

SR

the cisternae are enlarged portions of the ____

myofibrils

the contractile proteins in a muscle fiber organized into elongated bundles.

sarcomere

the contractile unit of a m. fiber. Restated: the sm., functional unit of contraction is____

sacroplasma

the cytoplasm of a muscle fiber

A band

the dark area of a sarcomere. Mostly thick filaments

tendon or aponeuroses

the deep fascia extending beyond the length of the muscle and attach the muscle to bone, cartilage, or muscle.

The amount of work done by a skeletal muscle is:

the distance the weight is lifted multiplied by the weight.

For every cross-bridge formed...

the energy from the same ATP molecule that detaches the cross-bridge also forms the next one.

cisternae

the enlarged portions of the SR near the TT of the sarcolemma

cisternae

the expanded regions of the SR that are found on both sides othe TT are referred to as

perimysium

the fibrous connective tissue that surrounds fascicles within the muscle

aponeurosis

the fibrous sheet is found on the head and abdomen only and connects m.

fulcrum

the fixed point upon which a lever moves

Perfusion

the flow per given volume or mass of tissue in a given time (mL/min./g)

Blood Pressure

the force that blood exerts against a vessel wall • Measured at brachial artery of arm using sphygmomanometer - A close approximation of pressure at exit of left ventricle • Two pressures are recorded - Systolic pressure: peak arterial BP taken during ventricular contraction (ventricular systole) - Diastolic pressure: minimum arterial BP taken during ventricular relaxation (diastole) between heart beats • Normal value, young adult: 120/75 mm Hg

ACE inhibitor can improve

the function of a failing heart and slow progression of kidney disease due to high blood pressure or diabetes

Hyperpolarization, or afterpotential occurs because

the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level.

resting potential

the initial polarized state of the membrane

Sphygmomanometer

the instrument used to compress the artery and record pressures in the auscultatory method of determining blood pressure

H zone

the lighter central region of the A band that contains only myosin

SR

the loose network of flattened tubules that surrounds the myofibrils in muscle fiber is referred to as

fibers

the m. cells w/in a grp. such as teh biceps braccii are ind. called ____. A m. ____ is a multinucleated cell.

Mean arterial pressure (MAP)

the mean pressure one would obtain by taking measurements at several intervals throughout the cardiac cycle

transverse tubules

the membranous channel that extends inward from a m. fiber membrane and passes through the fiber

sarcoplasmic reticulum

the membranous network of channels and tubules within a muscle fiber, corresponding to the ER of other cells

In this experiment, immediately after the latency period has passed:

the muscle contracted isotonically and lifted the weight.

For an isometric muscle fiber contraction...

the muscle fiber length remains constant as the muscle tension changes.

In this experiment, when the muscle is stretched what happens to the length of the muscle fibers?

the muscle fibers get longer.

For an isotonic muscle fiber contraction...

the muscle tension remains constant as the muscle fiber length changes.

Which of the following muscles is voluntary? the muscle in the wall of the heart the muscle that extends the arm at the elbow the muscle in the wall of the urinary bladder the muscle of the stomach

the muscle that extends the arm at the elbow

During the latency period:

the muscle was contracting isometrically.

What happens when the ATP attaches the myosin head?

the myosin head breaks off from the actin binding site and then the ATPase, in the myosin head, hydrolyses the ATP into ADP + Pi "recocking" the head into the high energy position

the rate of ventricular conduction is best determined by the _______ on the ECG

the number of QRS complexes present within a specific unit of time

Whole muscles can respond in a graded fashion to stimuli by varying

the number of motor units recruited.

Whole muscles can respond in a graded fashion to stimuli by varying the force of contraction of individual muscle fibers. the number of motor units recruited. the amplitude of the action potential. the frequency of stimulus. thresholds.

the number of motor units recruited.

tropomyosin

the protein of actin that is a rod shaped protein spiraling around actin

What is the relationship with velocity of shortening vs. load for isotonic contraction?

the rate of muscle shortening is inversely related to the load of the muscle. A muscle with no laod wil shorten at its max velocity. As the load increases the velocity of shortening decreases. At max load there is no shortening.

load

the resistance

The functional unit of muscle contraction is

the sarcomere

The functional unit of muscle contraction is

the sarcomere.

Which of the following muscles aids inspiration by lifting the first two ribs? diaphragm internal intercostals rectus abdominis the scalenes

the scalenes

When the acetylcholine binds to the receptor sites...

the sodium channels open.

When the acetylcholine receptor sites are not occupied:

the sodium channels remain closed.

the P wave represents

the start of the electrical journey as the impulse spreads from the SA node downward from the atria through the AV node to the ventricles

Which of the following muscles divides the neck into two triangles? the spinalis the platysma the sternocleidomastoid the digastrics

the sternocleidomastoid

During unfused tetanus...

the stimuli arrive at the muscle fiber at such a rate that the muscle fiber is unable to completely relax between stimuli, and sequential contractions exhibit an equal contractive force that is greater than when the muscle fiber is allowed to rest completely.

During fused tetanus...

the stimuli arrive at the muscle fiber so rapidly that there is no muscle relaxation between stimuli, but rather, a continuous contraction of the muscle fiber.

In the sarcomere of skeletal muscle, myosin is found in:

the thick filaments

In the sarcomere of skeletal muscle, actin is found in:

the thin filaments.

latent period

the time between the stimulus or the electrical event and the mechanical event of contraction

relaxation period

the time in which the muscle is returning to its original length

contraction period

the time in which the muscle is shortening

Which of the following statements is not true regarding ventricular systole?

the ventricles relax. Ventricular systole refers to the point in time when the ventricles are contracting.

refractory period

the very brief time period after one stimulus during which the muscle is unresponsive to a second stimulus

Which of the following is a true statement about cardia muscle cells?

they are connected by intercalated discs, through which action potentials spread to all cells in the heart

Which of the following statements about the "heads" of the myosin molecules is true?

they can attach to different actin sites

What about the "heads" of the myosin molecules is TRUE?

they can attach to different sites on the actin filament

Describe the role of calcium ions in the contraction of a sarcomere. (4)

they interact with the tropomyosin molecule; to reveal binding sites on actin; allowing myosin heads to bind to exposed sites on actin filament; energy released from ATP moves myosin head back to its original position

The M line holds?

thick filaments in place

I band contains what kind of filament?

thin filament, light color

The __________ is described as two strands of actin molecules wrapped together.

thin filaments

What are the two kinds of myofilaments?

thin filaments thick filaments

The most common lever systems in the body are those that have the applied force between the fulcrum and the resistance. These are called ______ levers. first-class second-class third-class fourth-class fifth-class

third-class

I

this band becomes narrowed in a fully contracted musle

A

this band remains unchanged in a fully contracted muscle.

contraction ends

this happens when the actin filaments on opp. sides of the sarcomere come into contact and myosin comes into contact with the Z lines

TT

this is formed by an invagination of the m. cell's sarcolemma

A muscle fiber will respond to a stimulus when that stimulus reaches the _____ level. threshold relaxation rigor mortis recruitment resting

threshold

How do calcium ions enter the cytoplasm during an action potential in smooth muscle?

through the plasma membrane

The ________________ is the prime mover of dorsiflexion of the foot. tibialis anterior gastrocnemius soleus popliteus

tibialis anterior

dorsiflexes foot and inverts foot

tibialis anterior

ST segment

time when ventricles are ejecting blood

a very large fibrous protein that connects thick myosin filaments to z discs in the sarcomere

titin

What is the main function of heart valves?

to prevent backward flow of blood. Heart valves are one-way valves that prevent blood from flowing backward. For example, the AV valves only allow blood to flow from the atria to the ventricles. And the semilunar valves only allow blood to flow from the ventricles to the aorta and pulmonary trunk. When valves do not completely close, blood flows backward through the heart, creating an abnormal "sloshing" sound known as a heart murmur.

The term that means a continued mild or partial contraction of a muscle that keeps it healthy and ready to respond is muscle ___________. tetanus summation tone stimulation twitch

tone

A muscle whose name ends in the suffix -glossus would be found attached to the ___________. chin tongue lips jaw cheek

tongue

End-diastolic volume (EDV)

total amount of blood in ventricles

Trusses and arches which help form an internal scaffolding network, are found in

trabecular bone.

Transverse tubules

transmit muscle impulses into the cell interior.

Transverse tubules (what do they do)

transmit muscle impulses into the cell interior.

The binding of the chemicals to the muscle cell causes an electrical impulse to travel along the sarcolemma and down the _______ tubules.

transverse

muscle name that describes direction of fibers

transverse abdominis

The component of a muscle fiber that quickly transports a muscle impulse from the sarcolemma throughout the entire muscle fiber is called the

transverse tubule (T-bulule)

Smooth muscle lacks

transverse tubules and striations.

stabalizes, elevates, rotates, and retracts the scapula; helps extend the head with the scapula fixed

trapezius

The triangle of auscultation, commonly used to hear sounds of respiratory organs, is located near the border of the

trapezius and latissimus dorsi.

Each of the following terms is a descriptive term for a muscle's action, EXCEPT ____________. levator tensor pronator trapezius adductor

trapizius

prime mover of forearm extension

triceps brachil

normal heartbeat

triggered by the SA node typically 70-80 bpm

Which one of the following molecules or structures would least likely be found at a neuromuscular junction? (p. 10)

tropomyosin

a protein of muscle that forms a complex with troponin regulating the interaction of actin and myosin in muscular contraction

tropomyosin

Using your knowledge of muscle contraction, explain the difference in the results between A and B. (2)

tropomyosin covers binding site on actin; no cross bridges formed so ATPase activity on myosin head reduced

Calcium ions bind to ______ in order to initiate a muscle contraction.

troponin

In order for a skeletal muscle fiber to contract, calcium must bind to:

troponin

a complex of muscle proteins which, when combined with Ca2+, influence tropomyosin to initiate contraction

troponin

Action potentials are carried by the Purkinje fibers from the bundle branches to the ventricular walls.

true

After cross-bridges form, phosphate is released, followed by ADP.

true

After the passage of the action potential, the sodium-potassium pump reestablishes the resting membrane potential.

true

An action potential causes depolarization of the T tubule membrane.

true

An action potential causes depolarization of the T tubule membrane. True or False

true

Bones act as levers for movement.

true

Both smooth muscle contractions and skeletal muscle contractions involve thin (actin) filaments sliding over the thick (myosin) filaments. True or False

true

Ca++ is essential for skeletal muscle contraction

true

Calcium ion is released from the sarcoplasmic reticulum. True or False

true

Communication between neurons and skeletal muscle fibers occurs at specialized junctions called neuromuscular junctions.

true

During contraction, the myosin myofilaments shorten.

true

Each myosin protein has a globular head that extends outward from the myosin filament.

true

Each myosin protein has a globular head that extends outward from the myosin filament. True or False

true

For isotonic contractions, the shortening velocity of a muscle fiber is inversely proportional to the mass of the load.

true

If the post-synaptic membrane potential reaches threshold level, an action potential will be produced.

true

Muscles surrounding external body openings have a fascicular pattern that is circular.

true

Muscles that act as sphincters to close openings are called circular muscles.

true

T-tubules are invaginations of the sarcolemma of a muscle cell.

true

The end of the muscle, attached to the point that moves when the muscle contracts, is called the insertion.

true

The lining of the chambers and the covering of the heart are a simple squamous epithelium overlying a thin layer of loose connective tissue. A) True B) False

true

The muscle that inserts on the acromion and scapular spine is the trapezius.

true

The rhomboid major and minor are muscles that stabilize and retract the scapula.

true

True or False In the ventricles, the action potential travels along the interventricular septum to the apex of the heart, where it then spreads superiorly along the ventricle walls.

true

True or False: In the absence of calcium ions, tropomyosin partially conceals the myosin binding site on an actin filament, preventing contraction. (p. 9)

true

True or False: Muscles can atrophy even if their nerve supply has not been disturbed. (p. 12)

true

energy is needed to make muscles relax

true

in a contracting muscle the Z lines come closer together.

true

in isotonic contractions, the muscle changes in length and the tension remains constant through most of the contractile period

true

it takes about twice as long for a muscle to contract as it does to relax

true

lactic acid is an end product of anaerobic fermentation that contributes to muscle fatigue

true

relaxation occurs when Ca2+ is transported back into the sarcoplasmic reticulum

true

the area of the sarcomere that contains only thin and elastic filaments is the I band

true

the neurotransmitter that stimulates skeletal muscle is acetlycholine

true

the sequence of events that forms the link between electrical activity in the sarcolemma and the initiation of a contraction is called excitation-contraction coupling

true

the skeletal muscle complex known as the triad consists of the transfers tubule and terminal costernae

true

the sliding filament model explains how myofilaments slide past each other

true

In the ventricles, the action potential travels along the interventricular septum to the apex of the heart, where it then spreads superiorly along the ventricle walls.

true Firing of the SA node excites atrial cardiocytes and stimulates the two atria to contract almost simultaneously. The signal travels through the atrial myocardium and reaches the AV node. The signal at the AV node is delayed, giving the ventricles time to fill with blood before they begin to contract. Signals then travel through the AV bundle and Purkinje fibers. Consequently, the entire ventricular myocardium depolarizes within 200 ms after the SA node fires, causing the ventricles to contract in near unison. Signals reach the papillary muscles before the rest of the myocardium. Thus, these muscles contract and begin taking up slack in the tendinous cords an instant before ventricular contraction causes blood to surge against the AV valves. Ventricular systole begins at the apex of the heart, which is first to be stimulated, and progresses upward—pushing the blood upward toward the semilunar valves. Because of the spiral arrangement of ventricular cardiocytes, the ventricles twist slightly as they contract, like someone wringing out a towel.

What is recruitment?

turing on more and more motor units, to increase tension in whole muscles

caused by a stimulus, a quick cycle of contraction and relaxation is called?

twitch

Each actin filament is composed of _________________________.

two strands of actin molecules wrapped together

Each actin filament is composed of

two strands of actin molecules wrapped together.

Each actin filament is composed of:

two strands of actin molecules wrapped together.

twitch

type of contraction represented by a single stimulus/ contraction/ relaxation sequence

slow-oxidative fibers

type of muscle fibers that are most resistant to fatigue

cardiodilatin

vascular smooth muscle relaxant that facilitates vasodilation

The heart chambers that have just been filled when you hear the first sound are the

ventricles

QRS complex represents the

ventricular contraction

QRS wave

ventricular contraction - ventricular depolarization

QRS wave

ventricular depolarization

At what point in the cardiac cycle is the pressure in the heart the lowest

ventricular diastole

At what point in the cardiac cycle is the pressure in the heart the lowest?

ventricular diastole

The atrioventricular valves open during..

ventricular diastole

The atrioventricular valves open during...

ventricular diastole

The semilunar valves close during...

ventricular diastole

The atrioventricular valves open during __________.

ventricular diastole The atrioventricular valves refer to the tricuspid and mitral valves. While the ventricles are relaxed, also known as ventricular diastole, the papillary muscles on the inside of the ventricles tug on the chordae tendineae, pulling the cusps of these valves to an open position.

The semilunar valves close during __________.

ventricular diastole The semilunar valves refer to the aortic and pulmonary valves. While the ventricles are relaxed, also known as ventricular diastole, the pressures in the ascending aorta and pulmonary trunk are greater than the pressures in the ventricles. Since these one-way valves open into the vessels, the pressure difference causes them to close

During which phase of the cardiac cycle does aortic pressure reach its maximum?

ventricular ejection The volume of blood being forced into the aorta by the left ventricle during ventricular systole causes the highest pressure the aorta experiences.

Most of the decrease in ventricular volume takes place during which phase of the cardiac cycle?

ventricular ejection. As the ventricles contract, blood is forced through the semilunar valves and out into the arteries, resulting in a reduction in ventricular blood volume. At the end of this phase, ventricular volume is at a minimum−the "end-systolic volume" (ESV).

During which complete phase of the cardiac cycle do the atria both relax and contract?

ventricular filling Since the atrioventricular valves are open at rest, ventricular filling happens passively when the atria are relaxed and actively when the atria are contracted.

Most of the increase in left ventricular volume takes place during what phase of the cardiac cycle?

ventricular filling. During ventricular filling the AV valves remain open, which allows blood to flow from the atria into the ventricles. The passive flow of blood during this phase (before atrial contraction) accounts for roughly 80 percent of the increase in ventricular volume.

What causes them to close?

ventricular pressure > atrial pressure

What event causes the semi lunar valves to open

ventricular pressure > pressure in the arteries

What event causes the semilunar valves to open?

ventricular pressure > pressure int he great arteries (aorta and pulmonary trunk) leaving their chambers

What event within the heart causes the AV valves to open?

ventricular pressure is less than (<) atrial pressure

the T wave results from

ventricular relaxation which is a recovery of the ventricular muslce tissue to a resting state

T wave

ventricular repolarization

T wave

ventricular repolarization - Ventricular repolarization and relaxation

At what point in the cardiac cycle is the pressure in the heart the highest

ventricular systole

What point in the cardiac cycle is the pressure in the heart highest?

ventricular systole

What vessel is used to return blood from body to heart?

via superior and inferior venae cavae

When an action potential arrives at the axon terminal of a motor neuron, which ion channels open?

voltage-gated calcium channels

Channels that open or close in response to changes in the electrical charge or voltage across the plasma membrane are called ligand-gated or chemical-gated ion channels. non-gated ion channels. voltage-gated ion channels. obligated ion channels.

voltage-gated ion channels.

Where is smooth muscle mainly found?

walls of blood vessels and digestive tract organs

contraction

what happens when actin and myosin filaments slide past one another.

QRS Complex

when signal from AV node spreads through ventricular myocardium and depolarizes

Isotonic contraction

when the muscle is stimulated it is capable of holding the weight, but also shortens as well. l

m line

where myosin is attached

Bundle Branch Block (BBB)

wide QRS, ventricular depolarization is taking longer

A band

width remains constant during muscle contraction

cardiac output

• Cardiac output (CO) - amount ejected by each ventricle in 1 minute • Cardiac output = heart rate x stroke volume - About 4 to 6 L/min at rest • Cardiac reserve - the difference between a person's maximum and resting CO - Increases with fitness, decreases with disease

Chronotropic Effects of Chemicals

• Electrolytes - K+ has greatest chronotropic effect • Hyperkalemia - excess K+ diffuses into cardiocytes • Hypokalemia - deficiency in K+ - Calcium • Hypercalcemia - excess of Ca2+ • Hypocalcemia - deficiency of Ca2+

cardiac cycle phases time

• In a resting person - Atrial systole lasts about 0.1 second - Ventricular systole lasts about 0.3 second - Quiescent period, when all four chambers are in diastole, lasts about 0.4 second • Total duration of the cardiac cycle is 0.8 second in a heart beating 75 bpm

cardiac cycle phases

• Ventricular filling (during diastole) • Isovolumetric contraction (during systole) • Ventricular ejection (during systole) • Isovolumetric relaxation (during diastole) • The entire cardiac cycle (all four of these phases) are completed in less than 1 second

Twitch

A single action potential Not visible to the human eye

Chambers of the heart that *receive blood* from veins

Atrium

An action potential enters a neuron... a by diffusion. B by the T-tubules. C by the sarcolemma. D by the sarcoplasmic reticulum. E by the actin myofilament.

B

The phase of the cardiac cycle that involves *relaxation* is called

Diastole

What are the sounds of Korotkoff

Sounds that can be auscultated over a partially occluded artery

The phase of the cardiac cycle that involves *contraction* is called..

Systole

Choline formed from the breakdown of acetylcholine in the synaptic cleft is

Reabsorbed by the presynaptic terminal membrane.

Which of the following is not true?

Red fibers have fewer mitochondria than white.

cardiac muscle cells

branching chains of cells, uni- or binucleate striations; intercalated discs

Chambers of the heart that *pump blood* into arteries

Ventricles

Stroke Volume

Ventricular ejection

The bond between the action and myosin head is broken when

an ATP molecule binds to the myosin head

Myasthenia gravis is

an autoimmune disorder.

load

distal end of forearm, hand

Pressure point on the dorsum of the foot

dorsalis pedis

acetylcholinesterase

enzyme release into neuromuscular junction to break down acetlycholine

raises eyebrows

epicranius

dehydration could indicate

low water concentration in your blood

elevates mandible

masseter

troponin

protein that functions with tropomyosin to block m. contraction until Ca++ is present

producing movement

pulling on something to change its position

the path of blood from the *heart*, to the *lungs*, and *back to the heart* comprises the...

pulmonary circulation

what makes an EKG have a larger upward or downward peak

the greater intensity of the impulse and the greater the difference in the charges

T tubules

tube-like extensions of the sarcolemma that run over and around the SR are referred to as

Each myofibril has __________

two kinds of myofilaments

The ventricles begin to fill during...

ventricular diastole

Isovolumetric relaxation

ventricular filling, complete one cardiac cycle

What vessel is used to pump blood from heart to body?

via aorta (biggest artery)

What vessel is used to pump blood from heart to lungs?

via pulmonary arteries (deoxygenated)

What vessel is used to pump blood from lungs back to heart?

via pulmonary veins (oxygenated)

2

2

During contraction, the actin myofilaments shorten. T OR F

FALSE

A skeletal muscle fiber (cell) contains a single nucleus.

False.

A bundle of muscle fibers is known as a

Fascicle.

Which chambers of the heart are at the base of the heart? A) atria B) ventricles

...

the beginning of the muscle that typically does not move when a muscle contracts is called the what?

...

The atrioventricular valves open during... A) ventricular systole. B) ventricular diastole. C) atrial systole. D) atrial diastole. E) both atrial and ventricular systole.

B) ventricular diastole.

Closure of the AV valves occurs when: A) the second heart sound is heard B) ventricular pressure exceeds atrial pressure C) atrial pressure exceeds ventricular pressure D) ventricular pressure and atrial pressure are equal E) blood is ejected from the ventricles

B) ventricular pressure exceeds atrial pressure

The maximum amount of work done by the weight 120 grams. When compared with the response for a lighter weight like 40 gram, the response for the 120 gram weight:

Both of the above statements are true.

Endomysium

How are skeletal muscle cells electrically insulated from each other?

The sequence of travel by an action potential through the heart is?

Sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, Purkinje fibers

In the heart the action potentials originates in the ?

Sinoatrial nodes

In skeletal muscle, alternating light and dark bands are termed

Striations

Click on the "Latency Period" button in the Journal to display a graph of your data. What is the effect of increasing the weight on the latency period?

The latency period increased as the weight was increased.

The ventricles begin to fill during ventricular diastole? True or false

True

The first three branches off the aorta are the right, left, and middle coronary arteries. A) True B) False

b. false

pivot

bending your elbow

how do skeletal and muscular systems work together for their role in body support and movement?

blah blah blah

BP across the cardiac cycle

blood flow in arteries is pulsatile - Speed surges from 40 cm/s to 120 cm/s - Blood spurts intermittently from an open artery • In capillaries and veins, blood flows at steady speed - Bleeding from veins tends to be slow and steady • BP tends to rise with age - Arteriosclerosis - Atherosclerosis

ACE inhibitor allows

blood vessels to enlarge and dilate to reduce blood pressure

In the intact frog, muscles are held close to their resting length so that maximum tension can be achieved. Excessive shortening and lengthening of the muscle is prevented by:

bones and joints.

calmodulin

calcium binding protein that is involved in contraction of smooth muscle and nonmuscle cells, calcium-calmodulin complex activate myosin light-chain kinase--enzyme responsible for phosphorylation of myosin

Which of the following is necessary for cross-bridge binding?

calcium binds to the troponin molecule.

Muscle contractions are initiated by binding of ...

calcium ions to troponin

repolarization

change in sarcolemma after the wave of depolarization; Na+ channels close and K+ channels open, allowing K+ to create a positive charge outside the membrane

Therefore, layers of _______ ________ enclose and separate all parts of a skeletal muscle

connective tissue

What does titin connect?

connects thick filament to Z structure

What is the fifth step of muscle contraction?

contraction is terminated when Ca is pumped back into sarcoplasmic reticulum

isotonic contraction

contraction of muscle during which the muscle changes length and the tension remains constant through most of the contractile period

thick filaments consist mainly of the protein actin

false

The audible heart sounds are caused by the contraction of the atria and ventricles.

false Audible heart sounds are caused by the closing of the valves.

Atrial contraction accounts for most of the ventricular filling.

false Most ventricular filling happens passively while the atrioventricular valves remain open in between ventricular contractions. Atrial contraction plays a small role in ventricular filling.

The atria never contract due to passive ventricular filling.

false The atria contract and are responsible for the active filling that takes place just before the ventricular contraction.

The beginning of ventricular systole is when blood flowing back toward the relaxed ventricles causes the semilunar valves to close.

false Ventricular systole begins when the ventricles begin to contract.

Within a muscle, the fibers are divided into larger bundles called _____, each surrounded by its own connective tissue sheath.

fascicles

Where is a sarcomere found?

from z line to z line

sarcomere

functional unit of a skeletal muscle fiber

plantar flexes foot; flex leg at knee

gastrocnemius

A current research alternative to knee replacement involves

growing new bone that is both fibrous and strong.

convergent

has a broad origin; single tendon of insertion

Troponin has two subunits. is part of the myosin myofilament. is a long, flexible protein. has a calcium-binding site. binds to ATP.

has a calcium-binding site.

circulatory system

heart, blood vessels, blood, some include lymphatic system

bradycardia

heartbeat slower than 60 beats per minute

The sequence for skeletal muscle contraction is...

increased cytosolic calcium, which binds to troponin, which moves tropomyosin from blocking active sites on actin filament, which binds with myosin cross-bridges, resulting in contraction

propagation of the action potential

increased positive charge inside sarcolemma changes permeability of adjacent areas, opening voltage-regulated Na+ channels

Hypocalcemia

increases heart rate - low Ca+

number of muscle cells per motor neuron

innervation ratio

low blood volume could indicate

internal bleeding

after the meal the _________ receive priority and the skeletal muscles receive very little flow

intestines

cardiac muscle

involuntary intrinsic system regulation, hormones, and autonomic nervous system controls

smooth muscle

involuntary, automatic nerves, hormones, local chemicals

The electrical properties of cells are the result of ion concentration differences across the plasma membrane. receptor sites that are present on the plasma membrane. phosphorylation reactions within the cytoplasm. phospholipids in the cell membrane

ion concentration differences across the plasma membrane.

Sinoatrial node

is a pace maker that sets timing and rhythm of heart beat Brain signals it to send electrical impulses to both atria of heart to contract in unison

What happens to the sarcomere during muscle contraction?

it shortens

What happens to the A band during muscle relaxation?

it stays the same

Increasing the weight increased the latency period because:

it takes time to build up tension in the muscle and tendon to overcome the weight.

Functions of titin/ elastic filaments?

keep thick and thin filaments aligned with each other, resist over stretching, helps with elasticity

during vigorous exercise, there may be insufficient oxygen available to completely break down pyretic acid for energy. As a result, the pyruvic aced is converted to what?

lactic acid

myofilaments

precisely arranged in the myofibril, for the crossbanding in the sarcomere I band contains only thin filaments, which anchor at the dense Z line, A band consists of both thick and thin filaments (making this band birefringment, or anisotropic), ratio of thin to thick is 6 to 1, M line is formed by cross connections at the midpoints of the thick filaments, H band consists of thick filaments only

Pulse

pressure surges in an artery occurring during each contraction and relaxation of the left ventricle

What is the downside to knee replacement surgery?

pain and discomfort in bending the joint across the skin

Thick filaments of muscles in clams contain _________ which allows muscles to stay in a fixed state of contraction for up to a month

paramyosin

Muscles extend ________

passively

sinoatrial (SA) node

patch of modified cardiocytes in the right atrium, just under epicardium near the base of the superior vena cava. This is the pacemaker that initiates each heartbeat and determines the heart rate

P wave

produced from signal from SA node (depolarizing atria) - SA node fires, atria depolarize and contract - Atrial systole begins 100 ms after SA signal

tropomyosin

protein that blocks m. contraction until Ca++ is present

Too much acetylcholinesterase causes

rapid degradation of acetycholine.

Electrocardiogram (ECG or EKG)

records the *electrical activity* of the heart by *picking up the movement of ions* in *body tissues* in response to this activity. *Does not record action potentials*, but results from *waves of depolarization* *Does not record contraction* or *relaxation*, but the *electrical events leading to* contraction and relaxation

AV bundle or bundle of His

pathway by which signals leave the AV node. Bundle forks into right and left bundle branches, which enter the interventricular septum and descent toward the apex

Systolic pressure

peak arterial BP taken during ventricular contraction (ventricular systole)

Which of the following statements about the "heads" of the myosin molecules is TRUE?

they can attach to different sites on the actin filament

T tubules

they function to conduct electro-chemical impulse ( or action potentials) inside the fiber from the surface of the cell

what is the role of tropomyosin in skeletal muscles?

tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules

All of the following are filamentous proteins EXCEPT

troponin

Relaxation requires uptake of calcium ion by the sarcoplasmic reticulum. True or False

true

Smooth muscle and skeletal muscle fibers both have their contractions triggered by calcium ions. True or False

true

T tubules are invaginations of the sarcolemma of a muscle cell. True or False

true

The sliding of the myofilaments past each other cause the sarcomere to shorten

true

The sodium-potassium pump is involved in establishing the resting membrane potential.

true

Tropomyosin moves to expose myosin binding sites on actin. True or False

true

Troponin binds calcium ion and signals tropomyosin to move. True or False

true

True or False Action potentials are carried by the Purkinje fibers from the bundle branches to the ventricular walls

true

True or False The ventricles begin to fill during ventricular diastole.

true

True or False during the heart conduction system action potentials pass slowly through the atrioventricular node

true

True or False: Some disorders that affect the muscular system actually are caused by defects in the parts of the nervous system that control muscle contraction rather than in the muscle fibers themselves. (p. 17)

true

Unflexing of the myosin head requires ATP True or False

true

Unflexing of the myosin head requires ATP.

true

When cross bridges form and the muscle fibers contract, the actin myofilament slides past the myosin myofilament.

true

When you abduct your upper arm, the prime mover is the deltoid.

true

at maximal stimulus, the muscle is contracting at full strength and all motor units are recruited

true

cross bridges occur when myosin heads combine with the binding sites on actin

true

during the recovery period after exercise, the body's need for oxygen is increased

true

muscles are only able to pull, they never push

true

true or false? Ventricular contraction begins at the AV valves and progresses downward toward the apex of the heart.

true

The ventricles begin to fill during ventricular diastole.

true Most ventricular filling happens passively while the atrioventricular valves remain open in between ventricular contractions, a time known as ventricular diastole.

The P wave of the ECG coincides with ventricular filling.

true The P wave of the ECG coincides with ventricular filling.

a single contraction of a stimulated muscle

twitch

fast-oxidative fibers

type of muscle fibers that contract quickly and rely on aerobic respiration for ATP

fast-glycolitic fibers

types of fibers that have few mitochondria

Which of the following muscles is a common site for injections in infants who have poorly formed buttocks? sartorius pectineus rectus femoris vastus lateralis

vastus lateralis

An action potential arriving at the pre synaptic terminal causes:

voltage-gated calcium ion channels to open, and calcium ions to diffuse into the cell.

T/F? Each myosin protein has a globular head that extends outward from the myosin filament.

True

During which processes is ATP required during muscle contraction?

1) Ca pumped back in by Ca2+ ATPase pump 2) Myosin heads release from binding sites 3) Cock myosin heads back into high energy formation

List 4 things that increase contractility

1. Increased sympathetic stimuli 2. Certain hormones 3. Ca++ 4. Some drugs

Arrange the following in the proper order in which they occur at the postsynaptic side of a neuromuscular junction. 1. Action potential is propagated over the muscle cell membrane 2. Depolarization of the postsynaptic membrane 3. Sodium ions move into muscle cell

3, 2, 1

Ventricular myocytes

30-40bpm

Both thick and thin filaments

A band

Motor Neuron

A single nerve cell that extends from the Brain or Spinal Cord to a muscle or gland.

When the myosin head physically pulls the actin past the myosin toward the center of the sarcomere, what part of the ATP molecule is still attached?

ADP

T/F? The sodium channels in the cell membrane have receptor sites for acetylcholine.

True

T/F? This channel is formed by a channel protein.

True

T/F? Unflexing of the myosin head requires ATP.

True

Cardiac Myocytes

Striated myofibril bundles that have the intrinsic ability to "beat" or contract on their own without stimulation

Each myosin protein has a globular head that extends outward from the myosin filaments (T/F)

True

For isotonic contractions, the distance that the muscle fiber shortens is inversely proportional to the mass of the load.

True

In a contracting muscle the Z lines come closer together (T/F)

True

In a contracting muscle the Z lines come closer together.

True

What evidence is there that muscle contraction is caused by actin and myosin filaments sliding past one another? (1)

Changes seen in the band patterns on myofibrils

Large motor units

Climbing stairs, Moving a piano and Sitting upright.

Which of the following is NOT a known effect of illegal use of anabolic steroids in large dosages? A increased muscle size B kidney damage C diminished testosterone secretion D increased cardiovascular fitness E sterility

D

Smooth muscle and skeletal muscle fibers both have their contractions triggered by calcium ions. True False

True

What are the areas near the edge of the sarcomere containing only thin filaments?

I bands

Dead cells can no longer produce ATP. Soon after death, muscles contract, making the body stiff. From your knowledge of muscle contraction, explain why this happens. (3)

ATP attaches to myosin heads and detaches them from binding sites on the actin filament, making muscle relax; As no ATP is produced after death, none attaches to myosin heads; Remain attached to actin, leaving the muscle in a contracted state

T tubules are invaginations of the sarcolemma of a muscle cell. True False

True

T-Tubules are invaginations of the sarcolemma of a muscle cell (T/F)

True

What are the two types of muscle that are used involuntary? (2)

Cardiac muscle; Smooth muscle

At what we did you record a maximum amount of muscle shortening?

Between 20 to 60 grams.

Ca+ channel dependent

Sinus node (SA) and AV node with a slow conduction and fast automaticity

describes a route that blood can take in a normal human?

C) left atrium > bicuspid valve > left ventricle > aortic semilunar valve

All of the following are filamentous proteins EXCEPT A. tropomyosin. B. myosin. C. troponin. D. actin. E. troponin and tropomyosin.

C. troponin.

A group of one T tubule lying between two adjacent terminal cisternae is called a Sarcolemma Triad Terminal cisternae Sarcoplasmic reticulum T tubules

Triad

Right atrioventricular valve

Tricuspid

At rest, the active sites on actin molecules care covered by ________ and ___________, two contractile proteins that inhibit contraction.

Tropomyosin and Troponin

The atrioventricular valves open during?

Ventricular diastole

Purkinje fiber myocytes

40-50bpm

An action potential enters the depths of a muscle fiber by way of..

the T-tubules.

cisternae

the ____ are enlarged portions of the SR.

Freshly oxygenated blood is first received by the

(b) left atrium

Heart murmur

*Abnormal heart sounds* produced by abnormal blood flow through heart due to *defective heart valves* *Mitral stenosis* *mitral valve calcifies* and *impairs flow* between *left atrium and ventricle* - causes *pulmonary hypertension* *Incompetent valves* *do not close properly* due to *damaged papillary muscles* *Mitral valve prolapse* most *common* cause of *chronic mitral regurgitation* *Septal defects* *holes* in interventricular or interatrial septa which *allows blood to cross sides*

Continuous capillaries

*Adjacent endothelial cells* are *closely joined* found in *muscles, lungs, adipose tissue*, and the *CNS*

Left side of heart

- Fully oxygenated blood arrives from lungs via pulmonary veins - Blood sent to all organs of the body via aorta

The average number of muscle cells in a motor unit is about 5 23 200 2000

200

The neurotransmitter in the neuromuscular junction.... What is the neurotransmitter?

ACh causes ligand gated sodium channels in the muscle fiber to increase their permeability to sodium, which depolarizes the postsynaptic membrane

What happens to ACh after it's RELEASED into the synaptic cleft?

ACh binds to ACh RECEPTOR sites of CHEMICALLY-GATED ion channels on the "MOTOR END PLATE"

diffusion

ACh moves across the synaptic cleft by _____

How are slow-twitch fibres adapted for their function? (4)

Large store of myoglobin to store large amounts of oxygen; Rich supply of blood vessels to deliver oxygen and glucose; Numerous mitochondria to produce ATP; So adapted for aerobic respiration to avoid a build-up of lactic acid

tropomyosin

Part of actin filaments. A thin filament also has molecules of protein called WHAT (an elongated protein winds along the groove of the F actin). When a muscle fiber is relaxed, tropomyosin blocks the active sites of six or seven actins and prevents myosin from binding to them.

Which of the following is true during ventricular systole?

The AV valves are closed. At the beginning of ventricular systole, the one-way AV valves are forced shut. The AV valves remain shut throughout ventricular systole. This prevents blood from flowing back into the atria when the ventricles contract.

transverse tubules

The sarcolemma has tubular infoldings called WHAT, which penetrate through the cell and emerge on the other side. Each T tubule is closely associated with two terminal cisternae, running alongside it on each side. (Narrow tubes extend into the sarcoplasm. Filled with extracellular fluid. Close contact with the SR)

Neither thick nor thin filaments

Titin

Small motor units

Writing a note, Playing a piano and Following words on a page with your eyes.

In contracting muscle the what lines come closer together?

Z lines

troponin

a 3 unit protein. functions to bind to actin, binds to tropomyosin and bind to calcium

cardiac cycle

a. Ventricular filling i. End-diastolic volume (EDV) b. Isovolumetric contraction c. Ventricular ejection i. Stroke volume(SV) ii. Ejection fraction iii. End-systolic volume(ESV) d. Isovolumetric relaxation

What is the third step of muscle contraction?

action potential travels down t-tubules, which are adjacent to terminal cisternae; causes the release of Ca from cisternae; Ca then binds to troponin, causing shape change and because troponin is attached to tropomyosin, the shape change causes displacement of trypomyosin, revealing binding sites on the actin

endurance type activities

activities best suited for slow-oxidative fibers

muscle name that describes action

adductor longus

Where does 95% of the energy needed for contraction come from during moderate exercise? anaerobic glycolysis lactic acid aerobic respiration creatine phosphate

aerobic respiration

Chronotropic

affecting the rate or timing of a physiologic process, as the heart rate.

Factor/s which affect muscle tension in a whole muscle include Frequency of Stimulation Number of motor units recruited Degree of muscle stretch all are true

all are true

strain

excessive strain and possible tearing of a muscle caused by muscle overuse or abuse

myosin

large molecular protein complex composed of two identical heavy chains and two pairs of light chains, heavy chains are enzymatically cleaved to form two fragments, light and heavy meromyosin, light meromyosin makes up most of the rod-like portion of the molecule, whereas heavy meromyosin represents the globular head and a small part of the rod, cross bridges seen between the thick and thin filaments are formed by the heads of the myosin molecules plus a small part of its rod-like portion has enzymatic activity and ability to bind to actin to produce shortening of the sarcomere and myofibril ATPase required for contraction is localized in the myosin heads or crossbridges

Which of the following would contribute to muscular fatigue in the muscle fiber? the emotional state of an individual relative depletion of ATP reserves inability of the motor neuron to produce sufficient quantities of acetylcholine depletion of neurotransmitter blocked receptors in the postsynaptic membrane

relative depletion of ATP reserves

generation of heat

release of energy during metabolism

Ca2+

released by terminal cisterna into the sarcoplasm to bind with troponin

What happens to A band during sarcomere contraction?

remains unchanged

arrhythmia

resting heart that beats slower than 60 beats per minute or faster than 100 beats per minute is this

repolarization

restoration of membrane potential to resting potential

Diastasis

second one-third; slower filling

The sequence of travel by an action potential through the heart is...

sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, Purkinje fibers.

In the heart, an action potential originates in the...

sinoatrial node.

What happens to thin filaments during sarcomere contraction?

slide over thick filaments, and slide closer together

A band is what kind of filament?

thick filament, dark

Staggered arrays of myosin molecules are ______

thick filaments

skeletal muscle

voluntary via axonal endings of the somatic nervous system


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