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