EXAM ONE REVIEW

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thin filaments are primarily composed of which protein?

F actin

Anaerobic fermentation produces the same amount of ATP as aerobic respiration. (T/F)

False

A term refers to a sheet of connective tissue that separates neighboring muscles or muscle groups

Fascia

The sarcolemma of smooth muscle cells has pockets called ______ that contain calcium channels

caveolae

with skeletal muscle contraction, what is excitation?

process by which action potentials in a nerve fiber lead to action potentials in a muscle fiber

When excitation of a muscle fiber stops, the SR __________?

reabsorbs calcium

What occurs when calcium binds to troponin?

the troponin-tropomyosin complex changes shape and exposes the myosin binding sites (active sites)

What is excitation-contraction coupling?

events that link the action potential of the arcolemma to the activation of the myofilament contraction

What is the process by which action potentials of a nerve fiber lead to action potentials in the muscle fiber called

excitation

What phase of contraction links the action potential in the sarcolemma to the activation of the myofilament?

excitation- contraction coupling

What is most likely to be the action of the extensor digitorum? (Hint: What does the name mean?)

extend the digits

property allows muscle cells to stretch to as much as three times their contracted length?

extensibility

A term refers to bundles of muscle fibers, wrapped in connective tissue, within a muscle Compartments Striations Fascicles Tendons

fascicles

biceps brachii and the gastrocnemius are examples of ______ muscles

fusiform

The glycogen-lactic acid system utilizes what molecule(s) as fuel to generate ATP?

glucose

Muscle cells contain _____ a starch-like carbohydrate that provides energy during intense exercise.

glycogen

term refers to a muscle that produces most of the force during a particular joint action?

agonist

What is myosin ATPase?

an enzyme located in the myosin head that hydrolyzes ATP

The glycogen-lactic acid system relies on which form of metabolism

anaerobic

Lactic acid and a small amount of ATP are produced during which process

anaerobic fermentation

What are the two most important pathways by which ATP is generated in muscle cells?

anaerobic fermentation and aerobic respiration

Which is NOT a step of skeletal muscle contraction?

breakdown of creatine phosphate

When a nerve signal arrives at a synaptic knob, which voltage-gated channels open in the knob?

calcium channels

In smooth muscle, which protein does calcium bind to?

calmodulin

What regulatory protein is associated with the thick filament of smooth muscle and activates myosin light-chain kinase?

calmodulin

Under the microscope, muscle that has alternating light and dark regions is said to be which of the following?

striated

Skeletal muscle exhibits alternating light and dark bands called

striations

Smooth muscle is named for the fact that it has no?

striations

Connective tissue structures that attach bone to muscle are called __________?

tendons

Which occurs during muscle contraction?

the overlapping of myofilaments increases

What is muscle tone?

the partial contraction of resting muscles

What is a power stroke during muscle contraction?

the ratcheting of myosin head

genetic condition in which an abnormal form of the dystrophin protein is produced results in __________ dystrophy

Muscular dystrophy

How much does a muscle fiber shorten from a single cycle of power and recovery strokes by all the myosin heads?

1% of its resting length

Within a sarcomere, the overlap of actin and myosin produce the __________ bands.

A bands

What is the perimysium? 1) A layer of loose connective tissue layer surrounding each individual muscle cell 2) A connective tissue sheath bundling many muscle fibers into a fascicle 3) The plasma membrane of an individual muscle cell 4) A connective tissue sheath surrounding an entire muscle

A connective tissue sheath bundling many muscle fibers into a fascicle

What is calmodulin?

A protein that replaces troponin in smooth muscle cells

During contraction, each power stroke consumes one molecule of what

ATP

energy needed for short bursts of intense activity is provided by which of the following?

ATP and creatine phosphate

What is a motor unit?

All of the muscle fibers innervated by a single motor nerve fiber.

In flexing the elbow, the prime mover is the

Brachialis

What is the immediate trigger for the contraction of smooth muscle?

Calcium ions

What must occur before tropomyosin can shift, revealing the active sites that allow myosin heads to bind to the actin filaments

Calcium must bind to troponin

What is the ability of muscle cells to shorten called? Multiple choice question.

Contractility

The "cocking" of the myosin head, hydrolysis of ATP and the power stroke occur during which phase of skeletal muscle contraction?

Contraction

Place the following events in synaptic transmission at a cholinergic synapse in order: A - A postsynaptic potential is produced; B - Voltage gated calcium channels open and calcium enters the cell; C - ACh is released and diffuses across the synaptic cleft; D - A nerve signal arrives at a synaptic knob; E - Ligand gated sodium channels open and sodium enters the cell.A) B, C, D, E, AB) D, B, C, E, AC) B, D, C, A, ED) D, B, E, A, C

D, B, C, E, A (A nerve signal arrives at a synaptic knob, Voltage gated calcium channels open and calcium enters the cell, ACh is released and diffuses across the synaptic cleft, Ligand gated sodium channels open and sodium enters the cell, A postsynaptic potential is produced)

Which term refers to the loose connective tissue layer that surrounds each individual muscle cell Epimysium Endomysium Perimysium Fascia

Endomysium

In a sarcomere, the thick filaments attach to the __________ line, found in the middle of the H band

M-line

perimysium is a connective tissue sheath that surrounds which of the following? Individual muscle fibers Groups of muscles Muscle fascicles The entire muscle

Muscle fascicles

Knowing the innervation to each muscle enables clinicians to diagnose which of the following

Nerve, spinal cord, and brain stem injuries

The perimysium contains which of the following (select what applies) Blood vessels Nerves bone tissue Muscle spindles

Nerves Muscle spindles blood vessels

From excitation through contraction, the SR

Releases and reabsorbs calcium (Ca2+)

Which of the following are functions of endomysium? 1) Contains stretch receptors called muscle spindles 2) Separates individual muscle fibers 3) Provides the extracellular chemical environment for each muscle fiber 4) Creates room for capillaries and nerve fibers to reach every muscle fiber

Separates individual muscle fibers Provides the extracellular chemical environment for each muscle fiber Creates room for capillaries and nerve fibers to reach every muscle fiber

What is the function of a T tubule?

T tubules carry the action potential through the sarcoplasm

Aerobic respiration is important for producing energy for long term energy needs. (T/F)

TRUE

Skeletal muscle contraction helps produce body hear (T/F)

TRUE

What causes skeletal muscle cells to be striated?

The alternating light and dark regions of the sarcomeres

What does the length-tension relationship suggests about the generation of muscle tension?

The amount of tension generated during a contraction depends on the degree of stretch of shortening prior to contraction

Which is true of the light bands in skeletal muscles?

They are called I bands and are bisected by Z disc

What is a fascia?

Thick sheet of connective tissue separating neighboring groups of muscles

What is a myoglobin?

a molecule that stores oxygen in muscles

Myosin ATPase is an enzyme in the myosin head that hydrolyzes ATP to release energy. (T/F)

True

Because skeletal muscle is under the conscious control it is said to be?

Voluntary

During contraction, what causes a power stroke?

When myosin releases ADP and ratchets to low energy postion

When an overly shortened or overly stretched muscle fiber is stimulated, what kind of contraction is generated?

a weak contraction

At the synaptic knob of the motor neuron, calcium stimulates exocytosis of the synaptic vesicles to release the neurotransmitter ______ into the synapse

acetycholine

I bands are composed primarily of which protein?

actin

Which provides long term energy for a cell?

aerobic

Which process produces the most ATP?

aerobic respiration

What term is another word for prime mover? synergist antagonist agonist fixator

agonist

characteristic that allows muscles to pull on bones and organs to create movement is called

contractility

The step in which the muscle fiber develops tension and may shorten is called ______.

contraction

During short bursts of intense activity, ATP for muscle contraction is supplied by which of the following?

creatine phosphate

What protein links actin fibers to the inner face of the sarcolemma?

dystrophin

When muscles stretch and recoil, they recoil to a shorter length. What is this property called?

elasticity

Fatigue resistance is improved by ______ exercise which enhances the delivery and use of oxygen

endurance

Epimysium is a connective tissue sheath that wraps around which of the following?

entire muscle

The connective tissue layer that covers the entire muscle is called the ___________?

epimysium

What term refers to the connective tissue layer that surrounds the entire muscle Perimysium Endomysium Fascia Epimysium

epimysium

Which of the following is true of endurance exercise?

increases oxygen transport

The _____ of a muscle refers to the identity of the nerve that stimulates it.

innervation

Which describes smooth muscle?

it is slow to relax and slow to contract

All of the muscle fibers innervated by a single nerve fiber constitute a __________ unit.

motor unit

What does the sliding filament describe?

muscle contraction

Which can be measured by attaching stimulating electrodes to a nerve-muscle preparation and a recording device?

muscle strength

partial contraction of a resting muscle is known as which of the following?

muscle tone

Muscle cells contain __________ a red pigment that stores oxygen needed for muscular activity.

myoglobin

protein found in muscle cells that stores and then releases oxygen when needed is called

myoglobin

A record of the timing and strength of a muscle's contraction is called a

myogram

In a myofibril, a thick filament is composed of pairs of _____ molecules intertwined together.

myosin

Which protein makes up the thick filaments of a myofibril

myosin

A synapse is the point where a nerve fiber meets a target cell. When the target cell is a muscle fiber, this type of synapse is called a __________ junction.

neuromuscular junction

rectus abdominis and the sartorius are examples of ______ muscles

parallel

A muscle of uniform width with fascicles aligned along its longitudinal axis would be classified as a __________ muscle.

parallel muscle

Projections extending from the inner surface of the epimysium form which of the following Sarcolemma fascia endomysium perimysium

perimysium

The connective tissue layer that wraps fascicles is called the __________?

perimysium

term refers to the loose connective tissue layer that surrounds skeletal muscle fascicles

perimysium

Which stage of contraction occurs when the myosin releases ADP and flexes, pulling the thin filament toward the M line?

power stroke

Within skeletal muscle cells, what extends from one Z disc to the next and constitutes one contractile unit

sarcomere

portion of a myofibril from one Z disc to the next is called a

sarcomere

What does the term "brevis" mean in the name of a muscle?

short

What is a neuromuscular junction

site where a nerve fiber communicates with the muscle fiber

The prevailing theory regarding muscle contraction is called the _________ filament theory.

sliding filament theory

__________ muscle cells are uninucleate, non-striated, and fusiform shaped

smooth

__________ muscle tissue is typically slow to contract and slow to relax.

smooth

What describes a fusiform muscle? Thick in the middle and tapered at the ends fascicles are aligned in a uniform fashion along long axis of muscle forms ring around body opening feather-shaped with fascicles inserting into tendon

thick in the middle and tapered at the ends.

During contraction, the cocked myosin head binds to an exposed active site on the actin protein of the __________ filament to form a cross-bridge.

thin filament

A muscle that is broad at one end and narrower at the other is classified as a ___________ muscle.

triangular

pectoralis major and temporalis muscles are examples of ______ muscles

triangular

When a muscle is at rest, what molecule blocks the active sites on the actin molecules

tropomyosin

In a thin filament, each tropomyosin molecule has a small calcium-binding protein called _____ bound to it.

troponin

Which of the following are found in thin filaments (multiple)

troponin F actin Tropomyosin

How does an action potential move deep into the muscle cell?

via the T-tubules


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