Exam 4

Match each structure with the connective tissue layer that surrounds it. 1. Muscle cell 2. Fascicle 3. Muscle

1. Endomysium 2. Perimysium 3. Epimysium

Match each structure with the connective tissue layer that surrounds it. 1. Fascicle 2. Muscle cell 3. Muscle

1. Perimysium 2. Endomysium 3. Epimysium

Match the type of muscle tissue with its brief description. 1. No striations and involuntary 2. Striated and multinucleated 3. Autorhythmic with gap junctions

1. Smooth 2. Skeletal 3. Cardiac

Myosin heads directly use ______________ to transition to their _____________________ conformation, which enables them ready to bind to actin. a. calcium; energized b. ATP; energized c. ATP; non-energized d. calcium; non-energized

ATP; energized

The abnormal antibodies made by patients with myasthenia gravis interact with what portion of the motor end plate? a. The sodium voltage-gated channels. b. The sarcoplamsic reticulum calcium gates. c. Acetylcholine receptors on the muscle cell membrane. d. Acetylcholine receptors on the motor nerve axon.

Acetylcholine receptors on the muscle cell membrane.

Which of the following structures has the active sites to which the heads of the thick filaments will bind? a. Troponin b. Tropomyosin c. Sarcoplasm d. Actin e. Myosin

Actin

Which glial cell is starlike in shape and helps form the blood-brain barrier? a. Ependymal cells b. Microglial cells c. Oligodendrocytes d. Astrocytes

Astrocytes

Which of the following characteristics is common to oligodendrocytes and Schwann cells? a. Both are located in the CNS. b. Both form a myelin sheath around a single axon. c. Both provide myelination. d. Both can interact with multiple cells.

Both provide myelination.

Uncovering binding sites for myosin on actin myofilaments is involves troponin binding to a. T-tubules b. Tropomyosin c. Calcium ions d. Phosphate

Calcium ions

Which of the following parts of a neuron receives and processes information? a. Dendrite b. Axon c. Cell body d. Synapse

Cell body

What part of a muscle twitch begins as a repetitive power stroke, then pulls the thin filaments past the thick filaments, shortening the sarcomeres? a. Threshold b. Relaxation period c. Latent period d. Contraction period

Contraction period

___________ is the process in which action potentials in the nerve fiber lead to action potentials in the muscle fiber.

Excitation

Glial cells help neurons by generating action potentials. T/F

False

Satellite cells are multinucleate. True/False

False

Assign each characteristic to the appropriate type of muscle fiber: Fast Glycolytic or Slow Oxidative WORDBANK: 1. High glycogen content 2. High myoglobin content 3. Smaller fiber size 4. Red 5. Anaerobic 6. Easily fatigues 7. Many mitochondria 8. Fast ATPase activity

Fast Glycolytic: High glycogen content, Fast ATPase activity, Easily fatigues, Anaerobic Slow Oxidative: Red, High myoglobin content, Smaller fiber size, Many mitochondria

In a normally functioning muscle, the inability to contract and produce tension is called muscle _____.

Fatigue

A graph of a muscle twitch contains three periods. The period during which there is no change in external muscle tension (and no change in muscle length) is the ________ period.

Latent

Which glial cell acts as a phagocyte? a. Astrocytes b. Oligodendrocytes c. Microglial cells d. Ependymal cells

Microglial cells

Which is a characteristic of skeletal muscle from the selections below? a. Multinucleated b. Contains intercalated discs c. Lack of striations d. Under autonomic nervous control

Multinucleated

Which type of smooth muscle is innervated most similar to skeletal muscle, with muscle cells arranged as motor units and each cell stimulated by a single motor neuron? a. Multiunit smooth muscle b. Single-unit smooth muscle

Multiunit smooth muscle

Place the organizational level of muscle tissue in order, beginning with the entire muscle and ending with the smallest component. 1. Muscle fiber 2. Muscle 3. Myofibril 4. Fascicle 5. Myofilament

Muscle, Fascicle, Muscle fiber, Myofibril, Myofilament

Which is not a protein found in thin filaments? a. No exceptions; all are found in thin filaments b. Troponin c. Myosin d. Tropomyosin e. Actin

Myosin

Which protein makes up the thick filaments? a. Actin b. Myosin c. Myopathy d. Troponin e. Tropomyosin

Myosin

Cross bridges form between binding sites on actin myofilaments and a. Myosin heads b. Tropomyosin c. Calcium ions d. Troponin

Myosin heads

A motor neuron transmits the effect of a nerve impulse to the muscle fiber at a _________________.

Neuromuscular junction

What type of cells produce the myelin sheath in the central nervous system (CNS)? a. Neurolemmocytes b. Astrocytes c. Microglia d. Oligodendrocytes

Oligodendrocytes

The type of muscles in which the fascicles are at an oblique angle to the tendon and the muscle fibers resemble a large feather is called a. convergent. b. parallel. c. circular. d. pennate.

Pennate

Myelin sheaths mainly consist of which part of the glial cells that form them? a. Perivascular feet b. Plasma membranes c. Cytoplasm d. Nucleus

Plasma membranes

Graded potentials that occur in postsynaptic neurons are called ___________ potentials.

Postsynaptic

An action potential for a muscle cell is propagated along the a. Sarcomere b. Sarcoplasm c. Sarcolemma d. Tropomyosin

Sarcolemma

Myofilaments within myofibrils are arranged in repeating microscopic cylindrical units called ____________.

Sarcomeres

Calcium ions released from the sarcoplasmic reticulum enter the a. Nucleus b. Sarcoplasm c. T-tubules d. Sarcolemma

Sarcoplasm

Another term for the __________ nervous system is the afferent nervous system.

Sensory

Which of the following muscle characteristics characterize an effect of aging? a. Increase in muscle fiber diameter b. Increase in myoglobin content in muscle c. Slow, progressive loss of muscle mass d. Increase capacity to recover from disease

Slow, progressive loss of muscle mass

Which type of muscle tissue is found in the walls of hollow organs? a. Skeletal muscle b. Cardiac muscle c. Organ muscle d. Smooth muscle

Smooth muscle

One of the names for the areolar connective tissue and adipose connective tissue that separates muscle from skin is ______________ fascia.

Superficial

An action potential enters a muscle cell at the a. Sarcomere b. Nucleus c. Actin myofilaments d. T-tubule

T-tubule

Action potentials then open voltage ion gates in the _____________, releasing calcium from the sarcoplasmic reticulum (SR) into the cytosol.

T-tubules

Invaginations of the muscle cell membrane that extend deep into the cell are known as the a. T-tubules. b. end plates. c. Z-discs. d. terminal cisternae. e. titin complexes.

T-tubules.

Which of the following connects muscle to bone? a. Cartilage b. Ligaments c. Menisci d. Epithelial tissue e. Tendons

Tendons

Which are the reservoirs that store the calcium required for muscle contraction? a. Synaptic clefts b. Mitochondria c. Terminal cisternae d. Peroxisomes e. Synaptic vesicles

Terminal cisternae

Which of the following refers to a sustained muscle contraction? a. Latency b. Tetanus c. Relaxation d. Fatigue e. Summation

Tetanus

Since Amy's myasthenia gravis was linked to the benign thymic tumor that was removed, why did her symptoms not immediately improve after its removal? a. Amy had developed resistance to the medications she was taking. b. The abnormal antibodies persist for several weeks, and thus her symptoms were prolonged. c. Amy's muscles had been deprived of stimulation for so long, they had withered.

The abnormal antibodies persist for several weeks, and thus her symptoms were prolonged.

How do medications that improve the symptoms of myasthenia gravis work? a. hey interact directly with the sodium voltage-gated channels of the muscle cell membrane to increase the intensity of the membrane depolarization. b. They directly stimulate the calcium voltage-gated channels of the sarcoplamsic reticulum to release calcium, thus initiating muscle cell contraction. c. They decrease the breakdown of acetylcholine, which results in an increased amount of ACh in the synaptic cleft and thus increased stimulus to the ACh receptors.

They decrease the breakdown of acetylcholine, which results in an increased amount of ACh in the synaptic cleft and thus increased stimulus to the ACh receptors.

If a muscle fiber is experiencing tetany and stimulation continues, the muscle reaches fatigue. T/F

True

The contraction phase of a muscle twitch has a shorter duration than the relaxation phase. T/F

True

Weaker contractions occur in muscles that are overly stretched because there is minimal thick and thin filament overlap for crossbridge formation. T/F

True

A ________ is defined as a single, brief contraction period and then relaxation period of a skeletal muscle in response to a single stimulation.

Twitch

"Intermediate fiber" is another name for a. a fast-twitch, oxidative fiber. b. a slow-twitch, oxidative fiber. c. a slow-twitch, glycolytic fiber. d. a fast-twitch, glycolytic fiber.

a fast-twitch, oxidative fiber.

Check all that are a function of the nervous system. a. Processing and evaluating information b. Collecting information c. Responding to information d. Production of red blood cells

a, b, c

Check all that are true statements regarding astrocytes. a. Astrocytes are the most abundant glial cells in the CNS. b. Astrocytes help form the blood-brain barrier by wrapping around capillaries in the brain. c. Astrocytes respond to infections in the CNS through phagocytic activity. d. Astrocytes assist in neuronal fetal development by secreting chemicals that regulate neuronal connections.

a, b, d

The typical skeletal muscle fiber contains several components that facilitate the production of ATP. Check all that apply. a. Mitochondria b. Myoglobin c. Myosin d. Glycogen

a, b, d

The chemical used at the junction with a skeletal muscle is ____________.

acetylcholine

The ions stimulate the release of _________ into the synaptic cleft.

acetylcholine

If you were studying the neurotransmitter released from axon terminals at a neuromuscular junction, you would be studying a. creatine phosphate. b. calcium ions. c. lactic acid. d. acetylcholine. e. ATP.

acetylcholine.

Areas of sarcolemma near the motor plate have gates that open moving ions, causing a(n) _________ potential that excites the muscle fiber.

action

Neurons are classified functionally according to the direction the ______________ travels relative to the ______. Afferent neurons are the neurons of the sensory nervous system. They are responsible for conducting ________ input from both somatic sensory and visceral sensory receptors. Most sensory neurons are ______. Efferent neurons are the neurons of the motor nervous system, conducting ________ output from the CNS to the effectors. All motor neurons are _________. Interneurons (or _______ neurons) lie entirely within the CNS. They receive stimulation from many other neurons and carry out the integrative function of the nervous system. The most numerous types of neurons are ________.

action potential; CNS; sensory; unipolar; motor; multipolar; association; interneurons

Pain receptors in the skin send signals to the CNS for processing. These pain receptors are an example of ____________ neurons. a. efferent b. association c. afferent d. multipolar

afferent

In order to maintain the electrochemical gradients for sodium and potassium, ATPase pumps move these ions __________ their respective gradients.

against

A flat, thin structure made of dense connective tissue that serves to attach a muscle to a bone (or to another muscle) is a(n) a. myolemma. b. tendon. c. perimysium. d. superficial fascia. e. aponeurosis.

aponeurosis.

A flat, thin structure made of dense connective tissue that serves to attach a muscle to a bone (or to another muscle) is a(n) a. tendon. b. myolemma. c. aponeurosis. d. superficial fascia. e. perimysium.

aponeurosis.

A decrease in muscular activity or damage to neurons that attach to skeletal muscle can lead to a reduction in the size of muscle called a. denervation. b. atrophy. c. dystrophy. d. rigor mortis. e. myasthenia gravis.

atrophy.

The motor division is separated further into a somatic motor division and a(n) _____________ motor division.

autonomic

Which is the correct order of the connective tissue layers of a skeletal muscle, beginning with the most superficial? a: Endomysium b: Epimysium c: Perimysium

b, c, a

Check all that are a function of skeletal muscle tissue. a. Metabolic regulation b. Body movement c. Maintenance of posture d. Heat production e. Regulating elimination of materials f. Protection and support

b, c, d, e, f

Check all that are proteins of thin filaments. a. Myosin b. Actin c. Troponin d. Titin (connectin) e. Tropomyosin

b, c, e

Check all of the statements that are true regarding the changes that occur in the muscular system as a result of aging. a. The number of myofibrils and myofilaments in existing muscle fibers increases. b. The elasticity of skeletal muscle decreases. c. There is an increase in fine motor control. d. There is a decrease in muscle fiber diameter.

b, d

Check all that are characteristics of cardiac muscle. a. Cells are long and cylindrical. b. Cells are short and branching. c. Cells have multiple nuclei at the periphery of the cell. d. Cells have one or two nuclei in the center of the cell. e. They are composed of thick and thin filaments. f. The functional contractile unit is the sarcomere.

b, d, e, f

Which major muscle lies sandwiched between the large posterior and the large anterior muscle of the arm? a. brachialis b. biceps brachii c. triceps brachii d. deltoid

brachialis

The process begins with a nerve signal stimulating a voltage-gated ___________ ion channel to open and the ions entering the synaptic knob.

calcium

A resting membrane potential of -70 mV indicates that the ________________. a. negative ions will always move into a cell b. positive ions outnumber the negative ions within the cytosol c. charges lining the inside of the plasma membrane are negative compared to the charges lining the outside d. negative ions are only present within the cytosol and are lacking in the extracellular fluid

charges lining the inside of the plasma membrane are negative compared to the charges lining the outside

When a neurotransmitter binds a protein channel, it opens and lets sodium diffuse down its concentration gradient. This is an example of a a. chemically gated sodium channel. b. sodium pump. c. leakage channel. d. voltage-gated sodium channel.

chemically gated sodium channel.

Progressively increasing force production allows the force to exceed that of the bar's inertia, and the ankle, knee, and hip extensors begin to contract ___________.

concentrically

The property of muscle tissue that allows an impulse to travel down the entire length of the cell membrane is a. responsibility. b. extensibility. c. conductivity. d. contractility. e. elasticity.

conductivity.

If there was a high concentration of acetylcholine within the synaptic cleft, but little to no response at the motor end plate, you would expect ________________ to be the responsible neuromuscular-blocking agent. a. curare b. botulinum toxin

curare

It is necessary that the neurotransmitter molecule is eliminated after each stimulation event. Its removal can occur by (1) _________, in which the neurotransmitter is chemically __________ in the ___________, and (2) _________, in which the neurotransmitter is reabsorbed by a neurotransmitter ___________________ in the membrane of the _________ neuron. These neurotransmitters are "recycled" once packaged into another _______________ for reuse.

degradation; inactivated; synaptic cleft; reuptake; transport protein; presynaptic; synaptic vesicle

Rather than tightly coupled synapses between neurons and muscle cells, single-unit smooth muscle contains a. plaques and caveolae that contain multiple hormone receptors for discrete endocrine control. b. diffuse junctions where neuron varicosities are responsible for neurotransmitter release. c. varicosities of a subset of muscle fibers so that individual cells can be separately stimulated. d. gap junctions that connect neurons to smooth muscle cells.

diffuse junctions where neuron varicosities are responsible for neurotransmitter release.

A message traveling from one presynaptic neuron to multiple postsynaptic neurons is an example of a ____ circuit. a. diverging b. parallel-after-discharge c. reverberating d. converging

diverging

The nervous system controls the activity of muscles and glands. Muscles and glands can generate changes and are therefore called a. effectors. b. stimuli. c. afferents. d. visceral.

effectors.

Neurons that carry signals from the CNS to skeletal muscle for contraction would be classified as _____________ neurons. a. bipolar b. unipolar c. afferent d. efferent

efferent

The diffusional movement of sodium and potassium across the membrane is driven at all times by the ______________________.

electrochemical gradient

There is then a rapid fluctuation in membrane voltage at the motor end plate called the _________ potential.

end-plate

The _____________ is the innermost connective tissue layer that surrounds each muscle fiber.

endomysium

The axon of a motor neuron travels through the epimysium and perimysium, and enters the _________, where it delivers a nerve impulse to an individual ________. a. muscle fiber; myofibril b. endomysium; muscle fiber c. muscle fiber; myofilament d. sarcolemma; myofilament

endomysium; muscle fiber

The axon of a motor neuron travels through the epimysium and perimysium, and enters the _________, where it delivers a nerve impulse to an individual ________. a. muscle fiber; myofilament b. endomysium; muscle fiber c. muscle fiber; myofibril d. sarcolemma; myofilament

endomysium; muscle fiber

The muscle whose name indicates that it extends at an angle to the longitudinal axis of the body is the a. external oblique. b. rectus abdominis. c. fibularis longus. d. semispinalis cervicis.

external oblique.

When ready, he initiates neural recruitment of his ankle, knee, and hip extensors first by increasing the ___________ of action potentials to the lower-limb extensors.

frequency

Myasthenia gravis represents a type of disease called a. vascular disease of the muscle. b. immune-mediated. c. neuromuscular end plate malfunction due to overuse. d. traumatic injury of muscle cells. e. nutritional deficiency.

immune-mediated.

Resting membrane potential is created as a result of a greater net flow of positive charges from the _________________________________.

intracellular fluid to the extracellular fluid.

No immediate movement of the bar is demonstrated despite the production of muscle force, which first demonstrates ________ contraction.

isometric

Neurotransmitters combine with their receptor sites and cause _____-gated ion channels to open.

ligand

The vagus nerve contains afferent and efferent neurons; therefore it is an example of a(n) __________ nerve. a. motor b. mixed c. afferent d. sensory

mixed

The antidote that holds the most promise to counteract the effects of tubocurarine is one that _____________________ a. modifies acetylcholine receptors so that they bind acetylcholine stronger than tubocurarine b. modifies acetylocholine so that it is unable to bind to acetylcholine receptors c. removes acetylcholine receptors from the end plate d. modifies acetylcholine receptors so that they can no longer bind acetylcholine

modifies acetylcholine receptors so that they bind acetylcholine stronger than tubocurarine

The peripheral nervous system is further subdivided into an afferent (sensory) division and an efferent (___________) division.

motor

The chemicals then bind to receptors located on the ____________________, a specialized area of the sarcolemma.

motor end plate

The specialized region of the sarcolemma that has folds and indentations to increase the membrane surface area covered by the synaptic knob is the a. motor end plate. b. synaptic cleft. c. synaptic vesicle.

motor end plate.

The specialized region of the sarcolemma that has folds and indentations to increase the membrane surface area covered by the synaptic knob is the a. synaptic vesicle. b. motor end plate. c. synaptic cleft.

motor end plate.

At this junction, the __________ releases a type of chemical called a ___________.

motor neuron, neurotransmitter

Voluntarily exerting more effort, additional __________ are recruited, which results in the production of greater forces.

motor units

The most common type of neuron contains many dendrites and a single axon. Structurally, this is classified as a(n) ______________ neuron. a. bipolar b. anaxonic c. unipolar d. multipolar

multipolar

Smooth muscle tissue in which cells are individually sent signals to contract (rather than contracting in unison) is referred to as a. multiunit. b. single-unit.

multiunit.

Threadlike bundles of thick and thin filaments

myofibril

Excitation-contraction coupling refers to the events that link the action potentials on the sarcolemma to activation of the _____________.

myofilaments

A single __________ molecule consists of two intertwined polypeptides forming a twisted filamentous tail and a double globular head.

myosin

Other active sites are open for _______ heads to bind and continue the contraction.

myosin

Calcium ions diffuse into the cell and cause synaptic vesicles to release __________.

neurotransmitters

Botulinum toxin causes muscle paralysis because ____________________. a. no acetylcholine enters the synaptic cleft b. calcium is removed from the neuromuscular junction c. the acetylcholine receptors at the motor end plate are blocked d. sodium is removed from the synaptic cleft

no acetylcholine enters the synaptic cleft

Acetylcholine causes an end-plate potential by triggering the ______________________. a. opening of calcium channels b. opening of chloride channels c. closing of sodium channels d. closing of calcium channels e. opening of sodium channels f. closing of chloride channels

opening of sodium channels

The type of muscles in which the fascicles are at an oblique angle to the tendon and the muscle fibers resemble a large feather is called a. pennate. b. convergent. c. parallel. d. circular.

pennate.

The cytoplasm within the cell body is called the ___________, although some anatomists use that term to describe the whole cell body. The nucleus accommodates a prominent __________, where ribosomes are formed. Free and bound ribosomes are known as Nissl bodies or _____________ substance. Short, small processes that branch off the cell body are _______. The _________ is sometimes called a nerve fiber. It is typically a longer process emanating from the cell body to make contact with other neurons, muscle cells, or gland cells. The cytoplasm within an axon is called _________, and the plasma membrane of an axon is called an _________.

perikaryon; nucleolus; chromatophilic; dendrites; axon; axoplasm; axolemma

An extensive network of blood vessels and nerve fibers extends through both the epimysium and the _____ of a muscle. a. myofilaments b. perimysium c. myofibrils d. endomysium

perimysium

An extensive network of blood vessels and nerve fibers extends through both the epimysium and the _____ of a muscle. a. perimysium b. myofilaments c. endomysium d. myofibrils

perimysium

Within a skeletal muscle, fascicles are separated from each other by connective tissue called the __________ , and muscle fibers are separated from each other by connective tissue called the __________ . a. epimysium; perimysium b. perimysium; endomysium c. endomysium; perimysium d. epimysium; endomysium

perimysium; endomysium

Neurolemmocytes produce myelin in the _____ nervous system. a. peripheral b. central

peripheral

The afferent or sensory division transmits impulses from __________________ to the ________________.

peripheral organs, CNS

When sodium enters the neuron via chemically gated sodium channels, the membrane will depolarize. Therefore, the membrane potential will become more negative. positive.

positive.

Though potassium and sodium both leak through the membrane at rest, there is a greater diffusional flow of _________ at rest.

potassium

Neurotransmitters diffuse from the ____________ terminal across the synaptic cleft.

presynaptic

If you were studying the functions of skeletal muscle, you would be studying all of the following except a. helping maintain a constant body temperature. b. movement. c. protecting internal organs. d. production of blood cells. e. holding the head erect.

production of blood cells.

If you were studying the functions of skeletal muscle, you would be studying all of the following except a. protecting internal organs. b. movement. c. helping maintain a constant body temperature. d. production of blood cells. e. holding the head erect.

production of blood cells.

Facial wrinkles, such as glabellar or "frown" lines, appear with aging as a result of natural, repetitive muscle contractions. Botox® helps alleviate the appearance of these wrinkles by _________________. a. destroying the motor nerves that serve the muscles responsible for forming the wrinkles b. overstimulating the facial muscles to tighten their appearance c. relaxing the facial muscles that cause the wrinkles d. overstimulating the facial nerves to produce a steady contraction of the facial muscles

relaxing the facial muscles that cause the wrinkles

Plasma membrane of muscle fiber

sarcolemma

Functional unit of contraction within muscle fiber

sarcomere

The contractile unit of a myofibril is called the a. sarcoplasm. b. M line. c. sarcoplasmic reticulum. d. sarcomere. e. sarcolemma.

sarcomere.

Cytoplasm of muscle fiber

sarcoplasm

First, a wave of action potentials spread from the end plate in all directions, reaching the T-tubules and then the _____________.

sarcoplasm

For relaxation to occur, a. sarcoplasm calcium levels fall, calcium is removed from troponin, and tropomyosin blocks binding sites on actin. b. calcium enters the myofibril, it detaches from myosin, and the binding sites on myosin become inactive. c. extracellular calcium levels fall, calcium is pumped into the myofibril, and tropomyosin slides away from actin. d. calcium leaves the sarcoplasmic reticulum, and troponin binds calcium and blocks the binding sites on actin.

sarcoplasm calcium levels fall, calcium is removed from troponin, and tropomyosin blocks binding sites on actin.

Site for storage of calcium

sarcoplasmic reticulum

The ___________ nervous system transmits information from receptors to the CNS, while the ___________ nervous system transmits information from the CNS to the rest of the body.

sensory; motor

Autonomic refers to the controls we are not aware of, like __________ muscle, cardiac muscles, and glands.

smooth

The electrical and chemical gradients for ________ are both high during resting membrane potential, which results in a very high electrochemical gradient toward the inside of the cell.

sodium

Normally, sodium and potassium leakage channels differ because ___________________. A. sodium leakage channels always remain open, but potassium leakage channels must be specifically activated to open B. sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell C. sodium leakage channels require ATP to transport ions, but potassium leakage channels do not D. sodium leakage channels are voltage-gated, but potassium leakage channels are ligand-gated

sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell

The site where the neuron communicates with the muscle fiber is called a ____________.

synapse

Acetylcholine (ACh) is released from motor neurons and enters the __________________. a. axon terminal b. sarcomere c. transverse tubules d. synaptic cleft

synaptic cleft

These chemicals diffuse across a small gap between the neuron and muscle fiber called the __________________.

synaptic cleft

The efferent or motor division transmits impulses from _______________ to the ________________.

the CNS out, peripheral organs

The diameter of a muscle fiber will predict a. how long its contraction will last. b. how fast it will relax. c. the amount of power it can generate. d. how fast it will contract.

the amount of power it can generate.

A _________ filament consists of 200 to 500 myosin molecules bundled together with the heads projecting outward in a helical array.

thick

The resting tension in a muscle generated by involuntary nervous stimulation is called a. wave summation. b. fatigue. c. tetany. d. tone.

tone.

The binding of the chemicals to the muscle cell causes an electrical impulse to travel along the sarcolemma and down the _________ tubules.

transverse

A thin filament consists of two intertwined chains of G actin molecules, smaller filamentous ____________ molecules, and troponin.

tropomyosin

Stimulation of muscle fibers at a rate of 20 to 50 stimuli per second does not allow for complete relaxation of the fibers before the next stimulatory event. This results in _________ and can lead to incomplete tetany. a. tone b. wave summation c. a muscle twitch d. tetany

wave summation

The aspect of Amy's history and physical exam that caused her doctor to pursue further tests was a. her irregular heart beat. b. weakness and a lack of stamina developed rapidly while testing grip strength. c. her difficulty driving. d. her history of recent swimming.

weakness and a lack of stamina developed rapidly while testing grip strength.

Symptoms and/or complications of myasthenia gravis include all of the following except a. death due to weakness of respiratory muscles. b. weakness of cardiac muscle contractions. c. progressive muscle fatigue and weakness.. d. loss of stamina. e. double vision.

weakness of cardiac muscle contractions.

Which glial cell is starlike in shape and helps form the blood-brain barrier? a. Astrocytes b. Oligodendrocytes c. Ependymal cells d. Microglial cells

Astrocytes

The diffusion of ______ into the cell or out of the cell causes a change in membrane potential.

ions

Site of ATP production

mitochondria

Channel formed by invagination of plasma membrane

transverse (T) tubule

Calcium will bind to the _____________ of the thin filaments.

troponin

Action potentials arriving at the presynaptic terminal cause _______-gated calcium channels to open.

voltage

Thin filaments connect to and extend from either side of a ___________. These thin filaments are composed largely of the myofilament ____________. a. Z disc; myosin b. M line; actin c. M line; myosin d. Z disc; actin

z disc; actin