A&P Midterm Review - Quiz 5 Flashcards

Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the neurotransmitter is released by exocytosis, diffuses across the synaptic cleft, and binds to its receptors.

A) refractory
B) contraction
C) relaxation
D) latent

True or False?

Muscle tone is the small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units.

Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials?

A) mechanically gated channel
B) ligand-gated channel
C) leakage channel
D) voltage-gated channel

Schwann cells are functionally similar to _______?

A) neurons

B) muscle cells

C) oligodendrocytes

D) red blood cells

What structure in skeletal muscle cells functions in calcium storage?

A) mitochondria
B) myofibrillar network
C) intermediate filament network
D) sarcoplasmic reticulum

Which of the choices below describes the ANS?

A) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
B) motor fibers that conduct nerve impulses from the CNS to skeletal muscles
C) sensory neurons that convey information from somatic receptors in the head, body wall, and
limbs and from receptors from the special senses of vision, hearing, taste, and smell to the CNS
D) sensory and motor neurons that supply the digestive tract

Using Figure 9.1, match the following:

1) Endomysium.

2) Fascicle.

3) The tissue that binds muscles into functional groups.

4) Perimysium.

5) Muscle fiber.

Using Figure 9.2, match the following:

1) I band.

2) H zone.

3) A band.

4) Z disc.

5) M line

Which of the following surrounds the individual muscle cell?

A) epimysium
B) endomysium
C) perimysium
D) fascicle

True or False?

In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier.

What does the central nervous system use to determine the strength of a stimulus?
A) frequency of action potentials
B) type of stimulus receptor
C) size of action potentials
D) origin of the stimulus

Collections of nerve cell bodies outside the central nervous system are called ________.

A) motor endplates
B) sarcoplasmic reticulum
C) oligodendrocytes
D) ganglia

Which of the following would be recruited later in muscle stimulation when contractile strength increases?

A) large motor units with small, highly excitable neurons
B) motor units with the longest muscle fibers
C) motor units with larger, less excitable neurons
D) many small motor units with the ability to stimulate other motor units

Which of the following describes the nervous system integrative function?
A) senses changes in the environment
B) analyzes sensory information, stores information, makes decisions
C) responds to stimuli by gland secretion or muscle contraction

True or False?

The peripheral nervous system is divided into afferent and efferent divisions

True or False?

An increase in the calcium ion level in the sarcoplasm starts the sliding of the thin filaments. When the level of calcium ions declines, sliding stops.

True or False?

During depolarization, the inside of the neuron's membrane becomes less negative.

True or False?

Axon diameter and degree of myelination determine nerve impulse conduction velocity.

The sliding filament model of contraction involves ________.

A) actin and myosin lengthening in order to slide past each other
B) actin and myosin sliding past each other and partially overlapping
C) the Z discs sliding over the myofilaments
D) the shortening of thick filaments so that thin filaments slide past

These cells in the CNS have cilia that move in order to circulate cerebrospinal fluid ______.

A) ependymal cells

B) astrocytes

C) oligodendrocytes

D) Schwan cells

During muscle contraction, myosin cross bridges attach to which active sites?
A) myosin filaments
B) Z discs
C) actin filaments
D) thick filaments

What is the role of tropomyosin in skeletal muscles?
A) Tropomyosin is the receptor for the motor neuron neurotransmitter.
B) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.
C) Tropomyosin is the chemical that activates the myosin heads.
D) Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.

True or False?

Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments.

What part of the sarcolemma contains acetylcholine receptors?
A) motor end plate
B) part adjacent to another muscle cell
C) any part of the sarcolemma
D) end of the muscle fiber

True or False?

excitability is the ability of a cell to receive and respond to stimulus by changing its membrane potential

Which of the following is not a function of the autonomic nervous system?

A) innervation of skeletal muscle

B) regulate heart rate

C) regulate digestion

D) regulate blood pressure

True or False?

A contraction in which the muscle does not shorten but its tension increases is called isometric contraction.

The effect of acetylcholine can be stimulating or inhibiting. Which of the following gives the best explanation for why this is so?
A) Acetylcholine has many different forms.
B) Acetylcholine has a "dose effect". Larger doses are stimulating while small doses inhibit.
C) Postsynaptic cells have a dynamic and changing metabolism and respond differently at different times.
D) Different post synaptic cells will have different receptors.

True or False?

The thin filaments (actin) contain a polypeptide subunit G actin that bears active sites for myosin attachment.

When a neurotransmitter like acetylcholine is acting in an excitatory manner which of the following is likely a result of the acetylcholine acting on the post synaptic cell?
A) Chemically gated chloride channels will open.
B) Chemically gated potassium channels will open.
C) Chemically gated sodium channels will open.
D) Chemically gated sodium channels will be closed.

The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________.

A) depolarization
B) absolute refractory period
C) resting period
D) repolarization

The term central nervous system refers to the ________.
A) brain and spinal cord
B) sensory (afferent) nerves
C) the somatic nerves
D) the spinal nerves

Sarcomeres are the functional units of _____ muscle.

A) smooth
B) cardiac
C) skeletal
D) cardiac and skeletal only

The contractile units of skeletal muscles are ________.
A) T tubules
B) myofibrils
C) microtubules
D) mitochondria

True or False?

One of the important functions of skeletal muscle contraction is production of heat.

Which of the following is NOT a function of dendrites?

A) provide enormous surface area for receiving signals from other neurons

B) generate nerve impulses and transmit them away from the cell body

C) convey incoming messages toward the cell body

D) produce short-distance signals called graded potentials

The strongest muscle contractions are normally achieved by ________.

A) increasing stimulus above the threshold
B) recruiting small and medium muscle fibers
C) increasing the stimulation up to the maximal stimulus
D) increasing stimulus above the treppe stimulus

After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?
A) the action potential stops going down the overloaded T tubules
B) acetylcholinesterase destroying the ACh
C) the tropomyosin blocking the myosin once full contraction is achieved
D) calcium ions returning to the terminal cisternae

When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods?
A) relaxation period
B) fatigue period
C) refractory period
D) latent period

Of the following muscle types, which has the longest muscle cells and has obvious stripes called striations?

A) multiunit smooth muscle

B) skeletal muscle

C) cardiac muscle

D) visceral smooth muscle

An excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle is ________.
A) gamma aminobutyric acid
B) norepinephrine
C) acetylcholine
D) cholinesterase

Muscle tone is ________.
A) the condition of athletes after intensive training
B) the ability of a muscle to efficiently cause skeletal movements
C) a state of sustained partial contraction
D) the feeling of well-being following exercise

The concentration of ions in the chemical environment surrounding the neurons must be tightly regulated for neurons to function properly. Which of the following cells is most responsible for this?
A) satellite cells
B) astrocytes
C) Schwann cells
D) oligodendrocytes

Bipolar neurons are commonly ________.
A) motor neurons
B) called neuroglial cells
C) found in the retina of the eye
D) found in ganglia

Saltatory conduction is made possible by ________.
A) large nerve fibers
B) diphasic impulses
C) erratic transmission of nerve impulses
D) the myelin sheath