anatomy micro muscle

T or F? The fastest mechanism for producing ATP is aerobic respiration.

False

T or F? A neuromuscular junction consists of one neuron and all the skeletal muscles it stimulates.

False

A motor neuron and all of the skeletal muscle fibers it stimulates are termed a ________. motor unit myofilament neurotransmitter synaptic cleft neuromuscular junction

Motor unit

One neuron and all the skeletal muscles it stimulates is known as a ________. neuromuscular junction motor unit sarcoplasmic reticulum synaptic cleft

Motor unit

Gap between the axon terminals and the plasma membrane of a neighboring muscle cell

Synaptic cleft

The action potential on the muscle cell leads to contraction due to the release of calcium ions. Where are calcium ions stored in the muscle cell? cytosol sarcolemma T tubule terminal cisterns (cisternae) of the sarcoplasmic reticulum

Terminals cisterns (cisternae) of the sarcoplasmic reticulum

Which one of the following is composed mostly of the protein myosin? thin filaments thick filaments light bands all myofilaments Z discs

Thick filaments

The binding of calcium to which molecule causes the myosin binding sites to be exposed? myosin troponin actin tropomyosin

Troponin

T or F? The sarcoplasmic reticulum wraps like a sleeve around the myofibril and stores and releases calcium.

True

When an action potential arrives at the axon terminal of a motor neuron, which ion channels open? voltage-gated calcium channels chemically gated calcium channels voltage-gated potassium channels voltage-gated sodium channels

Voltage-gated calcium channels

What changes occur in the sarcomere during muscle contraction? Z discs move closer together. I band increases in length. A band decreases in length. The thin filament shortens.

Z discs move closer together

What creates the alternating light and dark bands that provides the striation pattern on skeletal muscle tissue? H zones and M lines Z discs and H zones A bands and I bands sarcoplasm and sarcolemma thick filaments and myosin heads

a bands and i bands

Which of the following is NOT a function of the muscular system? blood cell formation stabilization of joints generation of heat production of movement maintenance of posture

blood cell formation

which of these characteristics applies only to cardiac muscle: involuntary intercalated discs stimulated by hormones striations

intercalated discs

Which connective tissue bundles muscle fibers into fascicles? endomysium epimysium perimysium tendons

perimysium

The plasma membrane of a skeletal muscle cell is called the ________. sarcoplasm sarcomere sarcoplasmic reticulum sarcolemma myofilament

sarcolemma

Which term does NOT describe smooth muscle cells? involuntary skeletal nonstriated visceral

skeletal

What is released by axon terminals into the synaptic cleft to stimulate a muscle to contract? acetylcholine actin sodium ions potassium ions myosin heads

Acetlycholine

Which neurotransmitter is released by motor neurons at the neuromuscular junction? acetylcholine sodium potassium acetylcholinesterase

Acetoycholine

Specific neurotransmitter that stimulates skeletal muscle cells

Acetylcholine

In a neuromuscular junction, synaptic vesicles in the motor neuron contain which neurotransmitter? serotonin dopamine norepinephrine acetylcholine (ACh)

Acetylcholine (ACh)

Enzyme that breaks down acetylcholine (ACh

Acetylcholinesterase

A myosin head binds to which molecule to form a cross bridge? troponin tropomyosin actin

Actin

Neurotransmitters are released upon stimulation from a nerve impulse from the ________. thick filaments sarcolemma of the muscle cell sarcoplasmic reticulum myofibrils axon terminals of the motor neuron

Axon terminals of the motor neuron

T or F? The neurotransmitter used by the nervous system to activate skeletal muscle cells is acetylcholine.

True

T or F? When a muscle fiber contracts, the I bands nearly disappear, the H zones disappear, and the A bands move closer together but do not change in length.

True

T or f? Aerobic, or endurance, exercise involves jogging or biking.

True

T or f? The formation of cross bridges requires both calcium ions and ATP.

True

There are three types of muscle tissue. Which of the following is classified as part of the muscular system? all skeletal muscles the heart all muscle tissue, including muscle of arteries, eyes, and the heart

all skeletal muscles

What is covered by the endomysium? an individual muscle cell smooth muscle only fascicles of muscle cells an entire muscle myofibrils

an individual muscle cell

Striated involuntary muscle tissue found in the heart is ________. skeletal muscle smooth muscle dense irregular dense regular cardiac muscle

cardiac muscle

What type of muscle tissue is both striated and involuntary? smooth muscle skeletal muscle cardiac muscle visceral muscle

cardiac muscle

-muscle tissue found only in the heart -muscle tissue composed of branching cells and intercalated discs

cardiac muscle tissue

Which layer of connective tissue surrounds each skeletal muscle fiber? perimysium aponeurosis epimysium endomysium

endomysium

What organelle wraps and surrounds the myofibril and stores calcium? sarcoplasmic reticulum sarcolemma sarcomere cross bridge

sarcoplasmic reticulum

Which type of muscle tissue contracts most quickly upon stimulation? tendons cardiac skeletal visceral smooth

skeletal

-voluntary muscle tissue -muscle tissue that is multinucleate -muscle tissue that maintains posture, body position, and stabilizes joints

skeletal muscle tissue

type of muscle in the picture

smooth muscle

-muscle tissue that dialates and constricts the pupils of our eyes -muscle tissue that activates arrector pili muscles to stand hairs on end -performs very slow, sometimes rhythmic contractiions

smooth muscle tissue

A sarcomere is ________. the wavy lines on the cell, as seen in a microscope the nonfunctional unit of skeletal muscle a compartment in a myofilament the area between two intercalated discs the contractile unit between two Z discs Submit

the contractile unit between two Z discs

What enzyme breaks down acetylcholine into acetic acid and choline to prevent continued contraction of the muscle fiber? calcium ions potassium ions sarcoplasmic reticulum acetylcholinesterase cross bridges

Acetylcholinesterase

During skeletal muscle contraction, to what do myosin heads bind? the H zone Z discs actin filaments myosin filaments thick filaments

Actin filaments

Electrical current that travels the length of the sarcolemma that results in the contraction of the muscle fiber

Action potential

What is the unstoppable electrical current that travels down the length of the entire surface of a sarcolemma? neurotransmitter action potential neuromuscular junction acetylcholine

Action potential

Part complete Which method of regenerating ATP during muscle contraction can produce lactic acid? direct phosphorylation oxidative phosphorylation creatine phosphate anaerobic glycolysis aerobic cellular respiration

Anaerobic glycosis

What causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell? arrival of an action potential calcium ion pump ATP troponin

Arrival of an action potential

What causes the myosin head to disconnect from actin? hydrolysis of ATP binding of calcium binding of ATP binding of troponin

Binding of ATP

What mineral is released within muscle cells to trigger contraction? sodium calcium potassium ATP

Calcium

The sarcoplasmic reticule stores this chemical

Calcium ions

What causes the power stroke? release of ADP and Pi binding of ATP hydrolysis of ATP calcium

Release of ADP and Pi

What type of exercise causes increase in muscle size? aerobic exercise infrequent exercise resistance exercise anaerobic exercise

Resistance exercise

Chemicall that enters a muscle cell upon excitation

Sodium ions

What must rush into a muscle cell to promote its depolarization? calcium ions potassium ions acetylcholine sodium ions acetylcholinesterase

Sodium ions

Striated involuntary muscle tissue is classified as ________ muscle. smooth skeletal cardiac either smooth or skeletal

cardiac

Creatine phosphate (CP) functions within the muscle cells by ________. 1, storing energy that will be transferred to ADP to resynthesize ATP as needed 2. storing energy that will be transferred to ATP to resynthesize ADP as needed 3, forming a chemical compound with actin 4. inducing a conformational change in the myofilaments 5. forming a temporary chemical compound with myosin

1

The mechanical force of contraction is generated by ________. 1. the temporary disappearance of thin filaments 2. the "accordian-like" folding of thin and thick filaments 3. A sliding of thin filaments past thick filaments 4. shortening of the thick filaments 5. shortening of the thin filaments

3

According to the sliding filament theory, how does muscle contraction occur? 1.A bands bunch up and shorten as myosin heads attach to thin filaments. 2.Both thick and thin filaments shorten as the muscle contracts. 3.Myosin heads attach and detach from thin filaments, causing thin filaments to shorten. 4.Myosin heads form cross bridges and pull thin filaments, causing them to slide.

4

How is acetylcholine (ACh) removed from the synaptic cleft? 1. simple diffusion away from the synaptic cleft and endocytosis into the muscle fiber 2. acetylcholinesterase (AChE; an enzyme) only 3. acetylcholinesterase (AChE; an enzyme) and endocytosis into the muscle fiber 4. simple diffusion away from the synaptic cleft and acetylcholinesterase (AChE; an enzyme)

4

The binding of the neurotransmitter to receptors on the motor end plate causes which of the following to occur? 1. Binding causes potassium voltage-gated channels to open in the motor end plate (junctional folds of the sarcolemma) and potassium enters the cell. 2. Binding causes chemically gated potassium channels to open in the motor end plate (junctional folds of the sarcolemma) and potassium enters the cell. 3. Binding causes voltage-gated sodium channels to open in the motor end plate (junctional folds of the sarcolemma) and sodium enters the cell. 4. Binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate (junctional folds of the sarcolemma) and sodium enters the cell.

4

The condition of skeletal muscle fatigue can be best explained by ________. 1. inadequate numbers of mitochondria in muscle cells 2. the inability to generate sufficient quantities of ATP due to feedback regulation of synthesis 3. A total lack of ATP in the body 4. the inability of the muscle to contract even if it is being stimulated 5. the all-or-none law

4

What initiates an action potential on a muscle cell? 1.ATP 2.acetylcholinesterase 3.myosin cross bridges binding to actin 4.acetylcholine binding to receptors on the sarcolemma within the neuromuscular junction

4

What is acetylcholine? 1. an oxygen-binding protein 2. A source of energy for muscle contraction 3. an ion pump on the postsynaptic membrane 4. a neurotransmitter that stimulates skeletal muscle to contract 5. A component of thick myofilaments

4

Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract? 1. Potassium ions diffuse out of the muscle cell. 2. Acetylcholinesterase (AchE) breaks down acetylcholine (ACh). 3. The sodium-potassium pump restores sodium and potassium back to their initial positions. 4. Sodium ions rush into the cell. 5. Acetylcholine (ACh) binds to receptors on the sarcolemma and allows passage of sodium ions into the cell.

5

Why are calcium ions necessary for skeletal muscle contraction? 1. Calcium ions increase the speed of the action potential transmitted along the sarcolemma. 2. Calcium ions bind to regulatory proteins on the myosin filaments, changing both their shape and their position on the thick filaments. 3. Calcium ions release the inhibition on Z discs. 4. Calcium ions cause ATP binding to actin. 5. Calcium ions trigger the binding of myosin heads to actin filaments.

5

Muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as ________. extensibility irritability elasticity contractility

Contractility

The heads of the myosin myofilaments are called ________ when they link the thick and thin filaments together during skeletal muscle contraction. synapses motor units cross bridges neuromuscular junctions

Cross bridges

What is the function of creatine phosphate? directly regenerates ATP from ADP within a muscle cell triggers anaerobic respiration catalyzes aerobic respiration makes oxygen available for aerobic respiration

Directly regenerates ATP and ADP within A muscle cell

What means of membrane transport is used to release the neurotransmitter into the synaptic cleft? a protein carrier exocytosis a channel

Exocytosis

What metabolic waste accumulates in muscle with excessive exertion? ADP creatine lactic acid carbon dioxide

Lactic acid

Which chemical is produced during vigorous exercise when the supply of oxygen is limited or inadequate? carbon dioxide lactic acid creatine glycogen

Lactic acid

What happens to a muscle when the nerve supplying that muscle is cut? The muscle hypertrophies. Muscle paralysis and atrophy occur. Myasthenia gravis develops. Muscular dystrophy develops.

Muscle paralysis and atrophy occur

The gap between the axon terminal of a motor neuron and the sarcolemma of a skeletal muscle cell is called the ________. motor unit neuromuscular junction sarcomere cross bridge synaptic cleft

Synaptic cleft