Muscular Tissue

myosin tail

(Twisted golf club handles); points toward the M line in the center of the sarcomere; tails of neighboring myosin molecules lie parallel to one another, forming the shaft of the thick filament.

Z line/ z disk

A dark thin protein band to which actin filaments are attached in a striated muscle fiber, marking the boundaries between adjacent sarcomeres.

Actin

A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells.

What is myoglobin? Multiple choice question. A carbohydrate that provides a muscle cell with energy An enzyme found in the synaptic cleft A molecule that stores oxygen in muscles A hormone that triggers contraction

A molecule that stores oxygen in muscles

motor unit

A motor neuron and all of the muscle fibers it innervates

Tropomyosin

A protein of muscle that forms a complex with troponin regulating the interaction of actin and myosin in muscular contraction

Myosin

A protein present in muscle fibers that aids in contraction and makes up the majority of muscle fiber

What is a neuromuscular junction? Multiple choice question. A passageway into a muscle for arteries and veins A site in the spinal cord where nerve impulses from the somatic receptors are received A site where a nerve fiber communicates with a muscle fiber Where a synaptic bulb is attached to a T-tubule

A site where a nerve fiber communicates with a muscle fiber

The energy needed for short bursts of intense activity is provided by which of the following? Multiple select question. -Oxygen -ATP -Creatine phosphate -Glucose

ATP Creatine phosphate

Myosin heads directly use __________ to transition to their __________ conformation, which enables them ready to bind to actin. calcium; energized calcium; nonenergized sodium; energized ATP; energized ATP; nonenergized

ATP; energized

Which process produces the most ATP? Multiple choice question. Aerobic respiration Anaerobic fermentation

Aerobic respiration

What is a motor unit? Multiple choice question. A muscle unit within the epimysium A single bundle of fascicles All of the muscle fibers innervated by a single motor nerve fiber All of the nerve fibers that innervate a muscle group

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

T tubules

Also called transverse tubules, these are deep invaginations of the plasma membrane found in skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell.

myosin heads

Bind to specific sites on actin molecules to form cross bridges

Which is not a step of skeletal muscle contraction? Multiple choice question. Hydrolysis of ATP Breakdown of creatine phosphate Binding of ATP to the myosin head Release of ADP from the myosin head

Breakdown of creatine phosphate

What happens to the sarcoplasmic reticulum when a skeletal myofiber is first stimulated? Multiple choice question. Calcium passively diffuses into the T-tubule Calcium is released into the sarcoplasm through gated channels Sodium is pumped into the sarcomere Neurotransmitters are pumped into the T-tubules

Calcium is released into the sarcoplasm through gated channels

What must occur before tropomyosin can shift, revealing the active sites that allow myosin heads to bind to the actin filaments? Multiple choice question. ATP has to bind to tropomyosin. The sarcomere has to shorten. Calcium must bind to troponin. Actin and elastic fibers have to recoil.

Calcium must bind to troponin.

Which is not naturally seen in the muscles of the body? Multiple choice question. Complete tetanus Wave summation Muscle twitch

Complete tetanus

thin filaments

Composed primarily of two protein strands called actin, has some tropomyosin, binds to head of myosin molecule

The "cocking" of the myosin head, hydrolysis of ATP and the power stroke occur during which phase of skeletal muscle contraction? Multiple choice question. Excitation Relaxation Contraction

Contraction

troponin and tropomyosin

Contraction Inhibiting Proteins within each sarcomere that are attached to actin

Striated muscle has _____________ alternating with _________________

Dark A bands\ light I bands

Sarcomere

Each segment of a microfibril from one Z-disk to the next is called a ______________

List the outer coverings from superficial to deep: endomysium perimysium epimysium

Epi peri endo

Thin filament are primarily composed of __________

F actin

Which of the following are found in thin filaments? Multiple select question. Myosin Tropomyosin Troponin F actin Titin

F actin troponin tropomysin

Smooth muscle location

Found in walls of hollow organs (e.g. intestines, blood vessels);respiratory passages, and in iris and ciliary body of eye.

H band I band Z disc A band

H band- 7 I band- 2 Z disc- 1 A band- 6

In high-intensity short-duration exercise, what does muscle fatigue result from? Multiple choice question. Increased potassium Increased oxygen Increased glycogen Increased ATP

Increased potassium

What type of contraction involves the development of tension but no change in length? Multiple choice question. Hypometric Isotonic Isometric Hypermetric

Isometric

When lifting something heavy, which type of contraction occurs first? Multiple choice question. Isotonic Isometric

Isometric

In what type of contraction does the internal tension build until it overcomes resistance and the muscle moves the load? Multiple choice question. Isotonic Isometric

Isotonic

What is the role of acetylcholinesterase? Multiple choice question. It is used by the muscle for energy. It breaks down ACh, ending muscle stimulation. It stimulates the motor end plate.

It breaks down ACh, ending muscle stimulation.

sarcoplasmic reticulum

Organelle of the muscle fiber that stores calcium.

What are anaerobic fermentation and aerobic respiration? Multiple choice question. Processes found only in muscle cells Pathways to generate ATP Transport mechanisms for calcium Methods of genera

Pathways to generate ATP

Skeletal muscle response speed

React quickly, tire quickly

During which phase of muscle contraction is calcium transported back into the cisternae and tropomyosin moves back to block the actin active sites? Multiple choice question. Relaxation Excitation-contraction Contraction Excitation

Relaxation

Troponin holds tropomyosin like scotch tape T/F

T

myofibrils contain thick and thin filaments T/F

T

What is the function of a T tubule? Multiple choice question. T tubules carry the action potential through the sarcoplasm. T tubules are one component of the rigor complex. T tubules store and phosphorylate ATP needed for contraction. T tubules store ACh.

T tubules carry the action potential through the sarcoplasm.

True or false: The sarcoplasmic reticulum releases calcium through gated channels when the T-tubules are stimulated. True false question. True False

true

What produces incomplete tetanus? Multiple choice question. Isolated twitches Temporal summation Infrequent stimuli Continuous sustained overlapping stimuli

Temporal summation

Thin filaments connect to and extend from either side of a __________. These thin filaments are composed largely of the myofilament __________.

z disc actin thin=actin

Place the steps of muscle relaxation in order. Tropomyosin covers the myosin binding sites AChE breaks ACh down The nerve signal ceases Calcium releases from troponin Active transport pumps in the sarcoplasmic reticulum begin to pump calcium back into the cisternae

The nerve signal ceases AChE breaks ACh down Active transport pumps in the sarcoplasmic reticulum begin to pump calcium back into the cisternae Calcium releases from troponin Tropomyosin covers the myosin binding sites

What occurs when calcium binds to troponin? Multiple choice question. Troponin shortens and triggers the generation of an action potential. ACh is released from synaptic vesicles. The troponin-tropomyosin complex changes shape and exposes the myosin binding sites (active sites). Troponin binds ATP and dephosphorylates, creating the rigor complex.

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

What do neurons and muscle cells have in common? Multiple choice question. Neurons and muscle cells are both multinucleate. Both cells shorten when stimulated. Their membranes undergo voltage changes when stimulated. Neurons and muscle cells are autorhythmic.

Their membranes undergo voltage changes when stimulated.

Tropomyosin Troponin calcium muscle fiber norepinephrine sodium acetylcholine receptor Relaxation begins when nerve signals stop stimulating the synaptic knob and _____________ release ceases. Acetylcholine dissociates from its __________ and is broken down enzymatically. Active transport pumps in the SR move _____________ ions back into the cisternae. ________________ moves back into position, blocking active sites, which prevents more contraction. If an appropriate force is applied, the ____________ returns to its resting length.

acetylcholine receptor calcium tropomyosin muscle fiber

The enzyme that breaks down acetylcholine is called

acetylcholinerase

Skeletal muscle location

attached to one or more bones

Describe perimysium

bundles muscle fibers together into fascicles

Gated channels in the sarcoplasmic membrane open to release which ions into the cytosol? potassium sodium calcium

calcium

When the signal comes from the nervous system, ___________ is released from the SR, causing the ____________ to contract or constrict

calcium myofibrils

The sarcolemma is the cell membrane of a muscle fiber cytoplasm of muscle cell

cell membrane of muscle fiber

A muscle shortens as it maintains tension in a what type of contraction? Multiple choice question. Eccentric Concentric Isometric

concentric

Describe endomysium

connective tissue that surrounds each skeletal muscle fiber

A band of sarcomere

contains all of the thick myosin filaments plus any overlapping think actin filaments

Myosin and actin are called

contractile proteins

Sarcoplasm=

cytoplasm of muscle cell

When muscles stretch and recoil, they recoil to a shorter length. What is this property called? Multiple choice question. Responsiveness Elasticity Conductivity Contractility

elasticity

Which prevents muscle cells from becoming too slack? extensibility elasticity

elasticity

In contrast to the action potential, the ______ potential causes the opening of ion channels, which results in the initial movement of sodium and potassium across the plasma membrane at the neuromuscular junction. If continued, this in turn can trigger an action potential at the neighboring sarcolemma. Multiple choice question. end-plate membrane electrical resting

end-plate

Muscle and nerve cells have developed which characteristic more than other cells? conductivitiy excitablitity movement

excitability

characteristics of muscle tissue

excitability, contractility, extensibility, elasticity, conductivity

in order to contract, a muscle cell must be ____________

extensible

True or false: A twitch is a sustained contraction in a whole muscle that occurs when a threshold level stimulus is reached.

false

The progressive weakness and loss of contractility that results from prolonged use of the muscles is known as muscle __________

fatigue

A skeletal muscle is composed not only of muscular tissue, but also...

fibrous connective tissue

Myofilaments

filaments of myofibrils, constructed from proteins, principally myosin or actin

Sarcomere

functional, contractile unit of a muscle fiber

Cardiac muscle location

heart

innervation of skeletal muscle

innervation of skeletal muscle

Cardiac muscle- voluntary or involuntary?

involuntary

smooth muscle- involuntary or voluntary?

involuntary

Which type of contraction maintains joint stability and posture? Multiple choice question. Concentric Isometric Isotonic Eccentric

isometric

The type of muscle contraction in which there is a change in length, but no change in tension is called a __________ contraction

isotonic

H band of sarcomere

lighter region on either side of the M line; contains thick myosin filaments but no thin actin filaments

The lower motor neurons in the spinal cord primarily control all the muscle cells in the _________

limbs, trunk

Myofibrils

long protein cords within the muscle fiber, fill most of the muscle cell

The neurons that tell our skeletal muscle to contract are ________ neurons

lower motor

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

motor

Functions of muscles

movement stability communication control of body openings and passages heat production glycemic control

Sarcolemma

muscle cell membrane

When calcium is released from sarcoplasmic reticulum, what happens?

muscle contracts

Endomysium surrounds muscle muscle fibers fascicles

muscle fibers

smooth muscle

muscle tissue in which the contractile fibrils are not highly ordered, occurring in the gut and other internal organs and not under voluntary control.

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

myoglobin

Which protein makes up the thick filaments of a myofibril? actin myosin troponin

myosin

Synapse between lower lower motor neuron and muscle cell is called _______-

neuromuscular junction

Acetylcholine causes an end-plate potential by triggering the __________. closing of sodium channels closing of calcium channels opening of calcium channels opening of chloride channels closing of chloride channels opening of sodium channels

opening of sodium

Describe epimysium

outermost layer, surrounds entire muscle

smooth muscle response speed

react more slowly but tire more slowly

The signal for muscle contraction starts on the ____________, travels down the _________ into a network of _____________, which then triggers _____________ to be released and muscle to contract

sarcolemma T tubule T tubules calcium

The portion of a myofibril from one Z disc to the next is called a(n) H band I band sarcomere

sarcomere

Hundreds of ____________ end to end compose a myofibril

sarcomeres

ID the three types of muscle tissue

skeletal cardiac smooth

The lower motor neurons in the cranial nerves primarily control the ________-

skeletal muscles of the head and neck

Acetylcholine (ACh) is released from motor neurons and enters the __________. multiple choice 1 transverse tubules axon terminal synaptic cleft sarcoplasmic reticulum sarcomere

synaptic cleft

motor end plate

the flattened end of a motor neuron that transmits neural impulses to a muscle

I band of sarcomere

the light band between the ends of thick filaments

Made of a bundle consisting of several hundred molecules of a motor protein called myosin, their heads directed outward

thick filament

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

The total supply of ATP and creatine phosphate in a muscle is enough to power contraction for about ______. Multiple choice question. 1 minute 15 minutes 30 minutes 1 hour

1 minute

Which cells have plasma membranes that undergo voltage changes in response to stimuli? Multiple choice question. Glial cells and osteocytes Glial cells and muscle cells Osteocytes and muscle cells Neurons and muscle cells

Neurons and muscle cells

True or false: The duration of exercise determines which muscle mechanism supplies ATP. True false question. True False

True

True or false: The sarcoplasmic reticulum releases calcium through gated channels when the T-tubules are stimulated.

True

Which is a quick cycle of contraction in a whole muscle that occurs when a threshold level stimulus is reached? Multiple choice question. Treppe Tetany Twitch Rigor

Twitch

Which is a quick cycle of contraction in a whole muscle that occurs when a threshold level stimulus is reached? Multiple choice question. Twitch Treppe Rigor Tetany

Twitch

How does an action potential move deep into the muscle cell? Multiple choice question. Via vesicular transport Via the T-tubules Via the intermediate filaments Via intracellular messenger molecules

Via the T-tubules

Skeletal muscle control- voluntary or involuntary?

Voluntary

Cardiac muscle response speed

Do not get tired

In muscle, what does the source of ATP depend upon? Multiple choice question. The location in the body The size of the muscle The number of fast glycolytic fibers The duration of exercise

Duration of exercise

Where does the end-plate potential occur? Multiple choice question. Sarcoplasmic reticulum T tubule Synaptic knob Motor end plate

Motor end plate

What does the sliding filament theory describe? Multiple choice question. Action potential propagation Synaptic transmission Muscle contraction

Muscle contraction

Within skeletal muscle cells, what extends from one Z disc to the next and constitutes one contractile unit? Multiple choice question. Terminal cisterna T tubule Thick filament Sarcomere

Sarcomere

Sarcoplasmic reticulum job is to

Store calcium, help control calcium release