Anatomy and Physiology Chapter 9: Muscles and Muscle Tissues FINAL

The synaptic ___ is the gap between a motor neuron and the muscle fiber at a neuromuscular junction.

cleft

Name the two muscles that are part of the pelvic diaphragm.

coccygeus and levator ani

Name the three sites of origin for the gluteus maximus.

coccyx, posterior ilium, sacrum

What is the action of the external oblique?

compresses the abdomen

As a result of the process called ___, maximal contraction of a whole muscle occurs as all motor units are activated.

recruitment

Name the process in which multiple motor units are activated in response to increasing intensity of stimulation, increasing the strength of contraction.

recruitment

The binding of acetylcholine to its receptors on the motor end plate results in increased membrane permeability to ___ ions.

sodium

The electrical impulse that moves over the surface of a muscle fiber and into the T tubules results from increased membrane permeability to what ion?

sodium

Increased membrane permeability to sodium results in the movement of sodium in which direction?

sodium moves into the cell

Within muscle myofibrils, the ___ filaments are composed of molecules of the protein called myosin.

thick

List two locations for multiunit smooth muscle.

walls of blood vessels and irises of the eyes

What is peristalsis?

wavelike contractions of smooth muscle

When is acetylcholine released into the synaptic cleft of a neuromuscular junction?

when a nerve impulse reaches the end of the axon

What muscle pulls up on the corner of the mouth, causing you to smile?

zygomaticus

What happens when CA ions bind to troponin?

It changes the position of the tropomyosin and they move so that the active sites of actin are exposed and then linkages can form between actin and myosin filaments

The product of glycolysis, pyruvic acid, is converted to ________ when oxygen is NOT available

Lactic acid

I bands

Lighter bands between each A band; contains actin

H zones

Lighter region in middle of A band; myosin

How can old people get muscle strength back/maintain it?

Lightly working out

Intermittent claudication

Limping condition that restricts blood delivery to the legs and has excruciating pains in the leg muscles while walking

What is a myofilament?

Long strands of muscle

What muscle inserts at the patella and the tibial tuberosity?

Quadriceps femoris

Muscles the extend the knee

Quadrieps emoris group, vastus medialis, vastus lateralis

Synaptic clefts

Recesses of muscle fiber that motor fiber branches into; *the nerve ending and motor end plate don't touch, this is the space between them*

myoglobin

Red pigment that stores oxygen, transports it

Conductivity

Response; generation of electrical impulse that passes along plasma membrane of muscle cell and causes cell to contract

Why are muscles not infected easily?

Rich blood supply

tropomyosin

Rod shaped; in longitudinal grooves of actin helix (longitudinal groove: Paige's hair)

Name the major extensors of the arm.

Teres major and latissimus dorsi

What muscle is responsible for plantar flexion and inversion of the foot?

Tibialis posterior

Synaptic vesicles

Tiny bubbles that contain neurotransmitters; main neurotransmitter acetylcholine (green balls in hook page 286)

both the sarcoplasmic reticulum and transverse tumbles function to___________________________

To activate the muscle contraction mechanism

tendons

Tough collagen fibers that withstand touch bony protections; small size-conserve space

Which muscle moves the pectoral gridle?

Trapezius

Babies' movements are ____ and ____

Uncoordinated and reflexive

Contraction of what muscle leads to closing the eyes?

orbicularis oculi

Contraction of what muscle leads to puckering of the lips?

orbicularis oris

The end of a muscle that is fixed (relatively immovable) is called its ___.

origin

Muscles that move the foot have their ___ on the femur, tibia, or fibula.

origins

Hormones can stimulate contraction in ___ muscle.

smooth

The sarcoplasmic reticulum is not well developed in ___ muscle cells.

smooth

_____ muscle tissue is found into the walls of hollow internal organs

smooth

Orbicularis Oculi

under the eye

Orbicularis Oris

under the mouth

A motor neuron and the muscle fibers that controls constitute a motor ___.

unit

List the muscles that form the quadriceps femoris.

vastus lateralis, rectus femoris, vastus intermedius, vastus medialis

Slow twitch/red muscle

"dark meat" lots of myoglobin and lots of mitochondria so does lots of cellular respiration to get ATP; does NOT fatigue easily; ex: back muscles (for posture) and thigh muscles

sarcoplasmic reticulum

"endoplasmic reticulum" of a muscle fiber; membranous channels that run parallel to and surround each myofibril

Transverse tubules

"t-tubules"; membranous channels that go from the sarcolemma all the way through the muscle fiber; open to the outside of the muscle fiber; invaginations of the sarcolemma; contain extracellular fluid

Muscles that move the foot will originate on the (a) ___, tibia, and/or (b) ___ (name the bones).

(a) fibula (b) femur

In comparing summation and recruitment, summation occurs within a (a) ___ and recruitment occurs within a (b) ___.

(a) single muscle fiber (b) whole muscle

Compared to skeletal muscle, smooth muscle is (a) ___ to contract and (b) ___ to relax.

(a) slower (b) slower

The pronator (a) ___ originates on the humerus and ulna, and the pronator (b) ___ originates only on the distal ulna.

(a) teres (b) quadratus

A muscle response called a(n) (a)___ consists of a period of contraction, during which the fiber pulls at its attachment, followed by a period of (b)___, during which the pulling force decreases.

(a) twitch (b) relaxation

Consider the types of smooth muscle. (a) ___ smooth muscle cells stimulate each other. (b) ___ smooth muscle requires stimulation by the nervous or endocrine system.

(a) visceral (b) multiunit

Steps for Contraction

1. Acetylcholine released and diffuses across gap at neuromuscular junction 2. Sarcolemma is stimulated, muscle impulse travels deep into fiber through t-tubules to sarcoplasmic reticulum 3. Ca ions from Saco ret are released into sarcoplasm and bind to troponin molecules 4. tropomyosin molecules move and expose binding (active) sites on actin 5. Linkages form between actin and myosin... actin filaments slide inward along myosin filaments...muscle fiber shortens-contraction

Skeletal muscle will be supplied with sufficient oxygen under with two conditions?

1. During moderate exercise 2. At rest

Two steps of cellular respiration

1. Glycolysis (2 ATP) 2. Aerobic respiration (34 ATP) - Citric Acid Cycle (Krebs's) (2 ATP) - Electron Transport Chain (32 ATP)

Rich blood supply because (2)

1. Uses huge mounts of energy 2. Removes numerous amounts of metabolic wastes

Steps for Relaxation

1. cholinesterase decomposes acetylcholine so sarcolemma is o longer stimulated 2. CA ions are actively transported back into the Saco ret 3. Linkages between actin and myosin are broken 4. Troponin and tropomysocin molecules inhibit the binding (active) sites of actin 5. Actin and myosin filaments slide apart...muscle fiber lengthens-relaxation

Actin molecules arranged in a ____ ___ to form an actin filament

Double helix

Actin (from notes)

1/4 total protein in skeletal muscle; globular structure with myosin binding sites attached to surface

Citric Acid Cycle

2 ATP; waste: carbon dioxide

__-__% of energy available from cellular respiration and ___% is lost as heat

20-25%; 75%

Electron Transport Chain

32 ATP; waste: water

Glucose molecule gives enough energy for __ ATP

36

Women's skeletal muscles make up approx. __% of body mass

36%

Motor unit

A motor neuron and the muscle fiber it controls; page 286-7

Men's skeletal muscles make up approx.. __% of body mass

42%

Muscle strength has usually decreased by ___% at 80 y/o

50%

myoblasts

A cell that builds muscles

Energy for contractions comes from what?

ATP

Equation for formation of ATP

ATP <=> ADP + P + energy

Elasticity

Ability of a muscle cell to recoil and resume resting length after being streched

Extensibility

Ability to be stretched or extended 1. Cell shorten when contracting 2. But can be stretched when relaxing

Excitability/Responsiveness/irritability

Ability to receive and respond to a stimulus (usually a chemical); the response is "conductivity"

Contractility

Ability to shorten forcibly when stimulated; sets muscles abort from others (muscles are only tissue with this ability)

Aerobic respiration

Aerobic; sequence of chemical reactions in which the bonds of fuel molecules are broken and the energy releases is used to make ATP (34 ATP); includes Citric Acid Cycle and Electron Transport Chain

Glycolysis

Anaerobic; first phase of cellular respiration that breaks glucose down into tow pyruvic acid molecules and tow ATP; occurs in cytoplasm (2 ATP)

Perimysium

Around each fascicles, is a layer of fibrous connective tissue

troponin

Attached to tropomyosin surface

M lines

Bisect H zones vertically; myosin linked by accessory proteins

Equation for creating phosphate

Creatine phosphate + ADP => creatine + ATP

sarcoplasm

Cytoplasm of muscle cell; has large amounts of glycosomes

A bands

Dark section that contains actin and myosin

Z line/disc

Darker midline bisecting in I bands; actin form one sarcomere connects to actin of next

atrophy

Decrease in size/muscle mass

Terminal cisternae

Enlarged portions of the sarcoplasmic reticulum; where calcium ions are stored

4 Characteristics of muscle tissue

Excitability/Responsiveness/Irritability Contractility Extensibility Elasticity

Fast twitch/white muscles

Few mitochondria and less myoglobin; gets most of its ATP through creating phosphate and Glycolysis and; DOES fatigue easily; found in muscles used in rapid movement

The ____ muscle fibers in a motor unit, the ___ movements of the muscle (example:__)

Fewer; finer; eye muscles

Frontalis

Forehead- when contracts, the eyebrows are raised

cross bridges (from notes)

Formed by the binding of myosin to actin. Generates the force that shortens the sarcomeres to bring about muscle contraction -In the presence of Ca (calcium) ions react with actin filaments and shorten the myofibrils - contraction; contain ATP binding sites

Platysma

Front of the neck

What is the immediate result of the opening of sodium channels along the sarcolemma (beyond the motor end plate)?

Generation of an action potential

Cellular respiration formula

Glucose + oxygen => carbon dioxide + water + ATP C6H12O6 + 6O2 => 6CO2 + 6H2O + Energy/ATP

sarcopenia

Gradual loss of muscle mass

__ movements precede __ ones

Gross, fine

Creatine phosphate

High energy molecule stored in muscles; tapped to regulate ATP while metabolic pathways are adjusting to higher demands for ATP; short-lived

At a ________ frequency of stimulation, a muscle can NOT relax between twitches. This leads to summation and a sustained smooth contraction called _________.

Hight; complete tetany

Cardiac Muscle

In the heart Involuntary Striated Steady and constant rate of contraction. Tetany does NOT occur in cardiac muscle

Smooth Muscle

In walls of visceral organs: hollow organs Involuntary No striations Slow, sustained rate of contraction (turtle) -TWO TYPES- multiunit and visceral

What is the outcome of the movements of the cocked myosin heads?

Increase in overlap between thin and thick filaments

As we age, our amount of connective tissue _____and number of muscle fibers ___

Increases, decreases

Muscular dystrophy

Inherited muscle-destroying diseases that appear in childhood; initially enlarge (due to fat) but then atrophy

______ ____ are found between the cells of cardiac muscle tissue.

Intercalated disks

When is the natural peak of motor control?

Mid adolescence

Many myosin ____ make up a myosin ______

Molecules, filament

Myosin (from notes)

Most abundant muscle protein (2/3's); one molecule is made of 2 twisted protein strands with globular corssbridges (heads) that project outward

Stimulation of what causes contraction?

Motor nerve fibers

Another name for muscle cells

Muscle fibers

fascicle

Muscle fibers grouped together; wrapped in perimysium

Indirect attachments

Muscle's connective tissue extents as tendon (or aponeurosis) anchors to the bone/cartilage/other-muscle-fascia; more common; smaller, durable

Each muscle is served by one ___, ____, and more than one ____

Nerve, artery...vein

Lactic Acid formation

Occurs when not enough oxygen is available to send pyruvic acid into aerobic respiration; due to extreme exercise; ex: muscles working hard due to running so can't get enough oxygen into body (lung capacity) so blood can't get to lungs to pick up more oxygen so causes oxygen deficit/debt

___ motor nerve fiber is connected to ____ muscle fibers so ___ muscle fibers connected to the same nerve fiber contract ______

One; many; all; simultaneously

Skeletal muscle

Organs that attach to/cover bony skeleton Rapid contraction, but tires easily (bunny) Striations voluntary

sarcolemma

Plasma membrane around muscle fiber

Cellular respiration

Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen; eating and breathing to get energy

Muscle functions

Producing body movement (locomotion, manipulation) Maintaining postures and body positions Stabilizing joints Generating heat (40% of body mass; most responsible for heat)

triad

Sarcoplasmic reticulum Transverse tubules Terminal cisternae

Duchesne muscular dystrophy

Sex-linked recessive disease; females carry and transmit; almost always males have it; 2-7 years old; healthy people become clumsy and fall as skeletal muscles fail; usually die in 20s

Neuromuscular junction

Site where motor nerve fibers and muscle fires meet; also called myoneural junction

The fibers of ____ and ____ are striated.

Skeletal and cardiac

*Other functions of muscle*

Skeletal muscles protect inner organs Smooth muscle forms valves for passage (sphincters) Dilate pupils of eyes

What are the three types of muscle tissue?

Skeletal, cardiac, smooth

sarcomere

Smallest contractile unit of muscle fiber; region of a myofibrils between two Z disks

Motor end plate

Specialized part of sarcolemma/muscle at the neuromuscular junction; sarcolemma is extensible folded; area has many nuclei and mitochondria

Development in a kid begins in ___ and radiates ___

Starts in head, radiates outward

contractures

State of continuous contractions; ex: writer's cramp

Muscle fatigue

State of physiological inability to contract even though the muscle still may be receiving stimuli; results from a relative deficit of ATP; not its total absence

When a muscle fiber is stimulated at a high enough frequency that is doesn't have time to relax, the forces of the individual twitches combine. What is the process called?

Summation

Gap junction is aka ____

Synaptic clefts

steroids

Synthetic male hormones

True or false: ATP is needed for both muscle contraction and muscle relaxation

TRUE

Smooth and cardiac do not do what?

They don't fuse

Myosin (Newville)

Thick filaments; solid with projections coming off; rod-like tail with two heads; 6 strands

Heart is pumping blood by what week?

Week 3

Skeletal muscle fibers are contracting by what week?

Week 7

Z Disks

What is 1?

Actin Myofilament

What is 2?

Myosin Myofilament

What is 3?

M Line

What is 4?

Cross-bridge

What is 5?

Sarcomere

What is 7?

Bone

What is A?

Tendon

What is B?

Skeletal Muscle

What is C?

Epimysium

What is D?

Fascicle

What is E?

Perimysium

What is F?

Endomysium

What is G?

Muscle Fibers

What is H?

Nuclei

What is I?

Capillary (blood vessel)

What is J?

Sarcoplasmic Reticulum

What is K?

Transverse (T) Tubule

What is L?

Sarcolemma (cell membrane)

What is M?

Mitochondria

What is N?

Myofibrils

What is O?

Striations

What is P?

Sarcomere

What is Q?

Actin Myofilament (thin)

What is R?

Myosin Myofilament (thick)

What is S?

Muscle's origin

When muscle contracts: immovable

Muscle's insertion

When muscle contracts: moveable

Which group of muscles would cause the extension of the leg at the knee? a. hamstrings muscles b. quadriceps femoris muscles

b. quadriceps femoris muscles

Endomysium

Whisky fine areolar connective tissue sheath around each individual muscle fiery; sheaths are continuous with each other; when muscle fibers contract, pull on sheath, pull on bone to be moved

Which three of the listed functions are associated with the rectus abdominis muscle? (select all that apply) a. tenses abdominal wall b. compresses abdominal contents c. rotates the pelvic girdle d. flexes vertebral column

a. tenses abdominal wall b. compresses abdominal contents d. flexes vertebral column

Receptors for the neurotransmitter ___ are found in the membrane of the motor end plate.

acetylcholine

The chemical called ___ is the neurotransmitter for skeletal muscle contraction.

acetylcholine

At a synapse, how is the action of acetylcholine stopped?

acetylcholine is broken down

Troponin and tropomyosin are part of the ___ filaments of muscle myofibrils.

actin

What are the two types of myofilaments?

actin myosin

Nerve endings controls ____

activity

The adductor longus, adductor magnus, and gracilis muscles all work to ___ the thigh.

adduct

What two terms refer to the contracting muscle the provides most of the force needed for a movement?

agonist and prime mover

Oxygen Deficit/Debt

alternative term for excess post-exercise oxygen consumption. When have less than amount of oxygen a body must take in for restorative process; causes arctic acid buildup; occurs when you don have enough oxygen in you body to send all the pyruvic acid into the aerobic part of cell respiration

Glycolysis is used to produce ATP for muscle contraction. Describe glycolysis.

anaerobic breakdown of glucose to produce ATP

A muscle that opposes the action at a joint is classified as a(n) ___.

antagonist

Contraction of muscles of the ___ group of the thigh will result in flexion of the thigh at the hip.

anterior

The flexors of the hand are located on the ___ side of the forearm.

anterior

A broad sheet of fibrous connective tissue that attaches a muscle to adjacent muscles is called a(n) ___.

aponeurosis

Aerobic respiration supplies skeletal muscle with sufficient oxygen under which two conditions?

at rest and during moderate exercise

List two of the actions of the deltoid muscle. (select all that apply) a. adducts arm b. extends humerus c. abducts arm

b. extends humerus c. abducts arm

What are tendons?

bands of dense connective tissue that attach to skeletal muscles to bones

Masseter

behind the mouth and in front of the ear

What is the meaning of the prefix "inter-" (as in "intercalated disc")?

between

biceps brachii

bicep region

The ___ ___ muscle originates at the ischial tuberosity and the posterior femur and inserts at the head of the fibula.

biceps femoris

Muscles that flex the knee

biceps femoris, semimembranosus, semitendinosus

Pectoralis Major

big chest muscle

Contraction of what muscle causes compression of the cheeks?

buccinator

Muscles "can" or "cannot" have both?

can

The cells of ___ muscle are striated, uninucleated and branching.

cardiac

This tissue makes up the bulk of the heart.

cardiac

Agonist

causes an action

A muscle fiber shortens and generates force during the ______ period of a muscle twitch.

contraction

There must be a high concentration of Cs ions for ____

contraction

Normal muscle activity involves:

contraction of many muscle fibers

Name muscles that flex the arm at the shoulder.

coracobrachialis and pectoralis major

The insertion of the brachialis muscle is the ___ process of the ulna.

coronoid

At the start of contraction, the first source of energy is used to convert ADP to ATP is ___ ___.

creatine phosphate

The amount of oxygen ___ after exercise equals the amount of oxygen needed to restore muscle levels of oxygen, creatine phosphate, and ATP, and allow liver cells to convert lactic acid back into glucose.

debt

Name the muscle that originates on the acromion process, the spine of the scapula, and the clavicle. This muscle then inserts on the humerus.

deltoid

What is the action of the tibialis anterior?

dorsiflexes and inverts foot

Junctions between cardiac muscle cells that allow muscle impulses to pass freely from one cell to another cell are ___ ___.

intercalated discs

Individual muscle fibers are surrounded by a connective tissue layer called the ___.

endomysium

ATPase

enzyme in myosin that breaks the ATP into DP and P so energy is released

Cholinesterase

enzyme that decomposes acetylcholine, located at neuromuscular junction in the membranes of the motor end plate

Anything that ends in ase =

enzymes

Together, the frontalis and occipitalis muscles form the ___ muscle.

epicranius

The layer of connective tissue that most closely surrounds an entire skeletal muscle is called the ___.

epimysium

Direct/fleshy attachments

epimysium of muscle fuses to periosteum of bone/pericardium of cartilage

The gluteus maximus ___ the thigh at the hip joint.

extends

Which muscle causes movement of the fingers?

extensor digitorum

The ___ ___ muscle of the abdomen inserts on the linea alba and the outer portion of the iliac crest.

external oblique

What is the term for the layers of dense connective tissue that separate individual skeletal muscles from adjacent muscles?

fascia

Muscle ___ is the inability of muscle tissue to contract.

fatigue

Muscles that move the thigh have attachments (origins and insertions) at what two areas?

femur and pelvic girdle

Individual muscle cells are called muscle ___.

fiber

What is the action of the iliacus?

flex thigh at hip

What is the action of the flexor carpi ulnaris?

flexes wrist and adducts hand

Name the action of the flexor carpi radialis muscle.

flexion of wrist and abduction of hand

The brachialis and biceps brachii are ___ of the forearm.

flexors

Glucose is stored into the form of___

glycogen

____ is a byproduct of cellular respiration

heat

Visceral smooth muscles are found in the wall of ___ organs.

hollow

The prefix ___ means "over" or "more".

hyper-

List the three areas of origin of the latissimus dorsi muscle.

iliac crest, spinous processes of lumbar and lower thoracic vertebrae, lower ribs

Where is cardiac muscle found?

in the walls of the heart

What is the insertion of the pectoralis major?

proximal humerus

hypertrophy

increase size/muscle mass; working out, exercising

What is summation?

increased force of contraction due to high frequency of stimulation to a muscle

At rest tropomyosin and troponin _____ active sites on actin so linkages between actin and myosin ____ be formed

inhibit; CANNOT

When a muscle contracts, its attachment point is called the ___ is pulled towards its origin.

insertion

Brachialis

inside bicep

Due to junctions called ___ ___, cardiac muscle can contract as a functional unit.

intercalated discs

What muscle compresses the abdomen and flexes and rotates the vertebral column?

internal oblique

What is the origin of the adductor magnus?

ischial tuberosity

Consider the naming of the temporalis muscle. What does the name tell you about the muscle?

it provides information about the origins and/or insertions for the muscle

During high-intensity exercise, anaerobic metabolism results in the production of pyruvic acid, which is then converted to ___ acid.

lactic

During a muscle twitch, the ___ period occurs between the stimulus and the increase in force of contraction.

latent

The vastus ___ has its origin on the greater trochanter and the posterior surface of femur.

lateralis

The ___ ___, found on the midline of the abdominal wall, is an attachment for some of the abdominal muscles.

linea alba

Sartorius

long muscle above femur

The ___ muscle originates on the zygomatic arch and inserts on the side of the mandible, allowing elevation and protraction of the mandible.

masseter

The temporalis and the ___ muscles produce chewing motions by elevating the mandible.

masseter

The muscles of mastication include the medial and lateral pterygoid, __________ and __________

masseter and temporalis

The action of the pronator teres is to ___ rotate the forearm.

medially

Rectus Abdominis

middle abs

Sternocleidomastoid

middle of the neck

Effectors such as skeletal muscles are controlled by what type of neuron?

motor neuron

Antagonist

oppose the action

What is the meaning of the prefix "myo-"?

muscle

What is the name for the continuous state of partial but sustained contraction in resting muscles?

muscle tone

The biceps brachii is an organ of the ___ system.

muscular

Within individual muscle fibers, ___ are threadlike structures composed of filaments of the proteins actin and myosin.

myofibrils

Within individual muscle fibers, _______ are threadlike structures composed of filaments of the proteins actin and myosin.

myofibris

The reddish-brown pigment that combines loosely with oxygen inside muscle cells is called ___.

myoglobin

During a muscle contraction, what happens when ATP binds to the myosin heads?

myosin cross-bridge release from actin

The force that shortens the sarcomeres to bring about muscle contraction comes from:

myosin cross-bridges pulling on the actin filaments

ATP (bound to myosin head) breaks down to ADP and phosphate

myosin hea dmoves into cocked position

ATP molecule binds to myosin head

myosin head (cross-bridge) releases from binding site on actin

Muscles are sometimes analyze as a result of damage to the ____ that are associated with them.

nerves

The specific synapse between a motor neuron and a muscle fiber is called a(n) ___ junction.

neuromuscular

Acetylcholine

neurotransmitter for skeletal muscle contraction; made in cytoplasm at distal end of a motor neuronal and stored in synaptic vesicles

In addition to acetylcholine, the neurotransmitter ___ can affect functioning of smooth muscle.

norepinephrine

The orbicularis ___ originates on the maxillary and frontal bones.

oculi

Name the connective tissue layer that separates a skeletal muscle into fascicles.

perimysium

The wavelike contractions that occur in the visceral smooth muscle of hollow organs are called ___.

peristalsis

Name the action of the soleus.

plantar flexes foot

Contraction of what muscle causes the lower lip and corner of the mouth to be pulled downward, as when frowning?

platysma

The extensors of the hand are located on the ___ side of the forearm.

posterior

List four functions of the muscular system.

propel body fluids and food, generate heart beat, movements, maintain muscle tone

Name the action of the sternocleidomastoid.

rotates head to one side

The teres minor and infraspinatus are primary ___ of the arm at the shoulder.

rotators

Name the "functional unit" of skeletal muscle.

sarcomere

What region of a myofibril is bounded by two successive Z lines?

sarcomere

Since the shortening of ___ results in shortening of entire skeletal muscles, these units are called the "functional units" of skeletal muscle.

sarcomeres

The cytoplasm of a muscle fiber is called the ___.

sarcoplasm

The membranous organelle within muscle fibers, called the ___ reticulum, corresponds to the endoplasmic reticulum of other cells.

sarcoplasmic

Name the invaginations of the sarcolemma that extend through the muscle fiber.

sarcoplasmic reticulum

What is the name of the network of membranous channels that surrounds each myofibril?

sarcoplasmic reticulum

Contraction of the trapezius causes rotation and retraction of the ___.

scapula

Tibialis Anterior

shin muscle

Deltoid

shoulder muscle

External Oblique

side of ribs

Cells of ____ muscle tissue have many nuclei.

skeletal

What are the three types of muscle?

skeletal, cardiac, smooth

The ___ of a muscle contraction explains how sarcomere shorten: thick and thin filaments slide past each other and do not change in length.

sliding filament model

The cross marking on skeletal muscles are called _____.

striations

Anything that ends in ose =

sugar

What two factors influence the force of contraction of a whole muscle?

summation and recruitment

List muscles that rotate the forearm.

supinator and pronator teres

Name the major abductors of the arm.

supraspinatus and deltoid

What is tetanic contraction?

sustained contraction with no relaxation

What is the term for the functional connection between a neuron and its effector?

synapse

The tiny vesicles in motor neurons that store neurotransmitters are called ___ vesicles.

synaptic

Any muscle that assists the agonist during a movement is called a(n) ___.

synergist

The tibialis anterior inserts on the first metatarsal and the ___ bone.

tarsal

The ___ muscle originates on the temporal bone and inserts on the coronoid process of the mandible.

temporalis

The ___ ___ muscle originates at the lateral border of the scapula and inserts at the intertubercular sulcus of the humerus.

teres major

cross bridges (Newville)

thick and thin filaments link during contractions; act as motors to create the tension developed by a contracting muscle cell ->***link that forms between actin and myosin****

Actin (Newville)

thin filaments, where myosin heads attach during contraction; two stands twisted together

A ___ stimulus is the minimum strength of stimulus necessary to generate a muscle contraction.

threshold

Muscles that move they leg insert on the ___ or the fibula.

tibia

The sartorius muscle inserts on the medial surface of the ___.

tibia

As ATP is broken down to ADP by the myosin-head ATPase, what is the released energy used for?

to move the myosin head into its cocked position

What is the role of neurotransmitters released by motor neurons?

to stimulate skeletal muscle cells

A continuous state of partial but sustained contraction in resting muscle is called muscle ___.

tone

A sustained contraction occurring in a muscle at rest is called muscle ___.

tone

Cisternae of the sarcoplasmic reticulum are positioned on either side of what structures?

transverse tubules

Numerous openings in the sarcolemma of a muscle fiber lead down into the ___.

transverse tubules

Name the extensor of the forearm.

triceps brachii

The muscle that originates from the tubercle below the glenoid cavity, the lateral humerus, and posterior humerus and that inserts on the olecranon process is the ___ ___.

triceps brachii

What three proteins form the thin filaments of muscle myofibrils?

tropomyosin, troponin, actin

Actin filament has two other proteins associated with it

tropomyosin; troponin