Practice Set 4B

Question 1

Which best describes an electrical current?

Answer 1

The movement of charged particles like ions

Question 2

Which term is used to refer to a cell membrane across which there is a separation of electrical charge, so that one side is more positive and the other side is more negative?

Answer 2

Polarized

Question 3

Which term refers to the voltage difference (electrical potential) across the plasma membrane of a neuron when it is at rest and not engaged in electrical signaling?

Answer 3

Resting membrane potential

Question 4

At rest, K+ diffuses out of the cell through leak channels, resulting in a slight local accumulation of positive charge on the outside of the membrane (due to excess K+) and a slight local accumulation of negative charge on the inside of the membrane (due to decreased K+). This describes the basis of the ________ membrane potential.

Answer 4

resting

Question 5

An electrical potential is a form of what type of energy?

Answer 5

Potential energy

Question 6

Which term refers to the flow of charged particles from one point to another?

Answer 6

Current

Question 7

Which of the following contributes to the development of the resting membrane potential in neurons?

Answer 7

K+ is more concentrated in the ICF than in the ECF.

Question 8

True or false: As long as there is an electrical potential across a cell membrane, we say that the membrane is polarized.

Answer 8

True

Question 9

Which is most likely to be the resting membrane potential of a neuron?

Answer 9

-70 mV

Question 10

At rest, K+ diffuses out of the cell through leak channels in the plasma membrane. Why does K+ diffusion result in a negative membrane potential?

Answer 10

It creates a slight local accumulation of K+ on the outside of the membrane relative to the inside.

Question 11

Which best describes an electrical potential?

Answer 11

A form of potential energy that can produce current

Question 12

Which ion has the greatest influence on the resting membrane potential of most neurons?

Answer 12

Potassium

Question 13

Which term is used to refer to a cell membrane across which there is a separation of electrical charge, so that one side is more positive and the other side is more negative?

Answer 13

Polarized

Question 14

Which term refers to the voltage difference (electrical potential) across the plasma membrane of a neuron when it is at rest and not engaged in electrical signaling?

Answer 14

Resting membrane potential

Question 15

Choose all of the following statements that are true about sodium?

Answer 15

Na+ is about 12 times as concentrated in the ECF as in the ICF.

The resting plasma membrane is much less permeable to Na+ than to K+.

Question 16

Choose all statements that are true regarding the Na+-K+ pump.

Answer 16

It moves Na+ out of the cell and K+ into the cell.

It helps maintain the proper ion distribution across the membrane.

It requires the use of ATP.

Question 17

Choose all that are characteristics of local potentials.

Answer 17

Graded

Decremental

Question 18

A negative membrane potential indicates which of the following?

Answer 18

The inside of the membrane is negatively charged relative to the outside.

Question 19

Why is sodium more concentrated in the ECF than in the ICF of most neurons?

Answer 19

Sodium is actively pumped out of the cell by transporter proteins

Question 20

Choose all that are true regarding the Na+-K+ pump.

Answer 20

It accounts for about 70% of the energy (ATP) required by the nervous system.

It helps maintain the proper ion distribution across the membrane, compensating for ion leakage.

Question 21

Which ion has the greatest influence on the resting membrane potential of most neurons?

Answer 21

Potassium

Question 22

Which term refers to decremental changes in electrical potential along a dendrite or the soma?

Answer 22

Local potentials

Question 23

Which term refers to the upward change in membrane potential during an action potential?

Answer 23

Depolarization

Question 24

A shift in membrane voltage to a value that is more negative than the resting membrane potential is called which of the following?

Answer 24

Hyperpolarization

Question 25

Choose all that are characteristics of local potentials.

Answer 25

Decremental Graded

Question 26

Place these events into the order in which they occur during a single action potential.

Answer 26

Local potential depolarizes membrane Threshold is reached Depolarization Repolarization Hyperpolarization

Question 27

During which part of the action potential do most voltage-gated sodium channels open?

Answer 27

Depolarization

Question 28

In order for local potentials to trigger an action potential, the membrane must depolarize up to a level called which of the following?

Answer 28

Threshold

Question 29

Which term refers to the period of time after a nerve cell has responded to a stimulus in which it cannot be excited by a threshold stimulus?

Answer 29

Refractory period

Question 30

Resting membrane potential Depolarization begins Repolarization begins

Answer 30

Both types of voltage-gated channels are closed. Voltage-gated Na+ channels open; voltage-gated K+ channels open more slowly. Voltage-gated Na+ channels inactivate; voltage-gated K+ channels remain open longer.

Question 31

The all-or-none law of action potentials states which of the following?

Answer 31

A neuron will fire at maximum voltage if a stimulus depolarizes it to threshold.

Question 32

After a nerve cell responds to a stimulus, the period of time when the cell can not respond again except to an unusually strong stimulus is called what?

Answer 32

Relative refractory period

Question 33

The refractory period in which no stimulus of any strength will trigger a new action potential is the ______ refractory period.

Answer 33

absolute

Question 34

What is a quick, involuntary, stereotyped response to a stimulus is called?

Answer 34

Reflex

Question 35

In order for local potentials to trigger an action potential, the membrane must depolarize up to a level called which of the following?

Answer 35

Threshold

Question 36

After a nerve cell responds to a stimulus, the period of time when the cell can not respond again, regardless of the strength of stimulus, is called the _____ refractory period.

Answer 36

absolute

Question 37

The refractory period in which it is possible to trigger a new action potential, but only with an unusually strong stimulus is the ______ refractory period.

Answer 37

relative

Question 38

Choose all that are components of a monosynaptic somatic reflex arc?

Answer 38

Receptor in skin, muscle or tendon Efferent nerve fiber Skeletal muscle Afferent nerve fiber

Question 39

Which stimulus causes a muscle to reflexively contract?

Answer 39

Increased stretch

Question 40

Which are true regarding the absolute refractory period? Select all that apply.

Answer 40

No stimulus of any strength will trigger a new action potential. It refers only to a small patch of the membrane; other parts of the neuron can still be stimulated while a small area of it is refractory. It occurs during the depolarization and repolarization phases of the action potential.

Question 41

In which reflex is there a quick contraction of flexor muscles in response to a painful stimulus?

Answer 41

Flexor

Question 42

A reflex in which a contralateral extensor muscle is contracted is called a __________ extension reflex.

Answer 42

crossed

Question 43

Place the components of a reflex arc in order.

Answer 43

Receptor Afferent nerve fiber Integration center Efferent nerve fiber Effector

Question 44

In response to stretching, a muscle reflexively does which of the following?

Answer 44

Contracts

Question 45

A quick contraction of flexor muscles in response to a painful stimulus is called a _______ reflex.

Answer 45

flexor

Question 46

A reflex that occurs in response to excessive tension on a tendon is called a(n) ______________.

Answer 46

flexor reflex

Question 47

Which is usually under involuntary control?

Answer 47

Autonomic nervous system

Question 48

Which nervous system has two nerve fibers connecting the CNS to an effector?

Answer 48

Autonomic

Question 49

What does the axon of a postganglionic neuron synapse with?

Answer 49

An effector

Question 50

Which reflex occurs in response to excessive tension on a tendon?

Answer 50

Tendon

Question 51

Which nervous system regulates conscious, voluntary movements of the skeletal muscles?

Answer 51

Somatic nervous system

Question 52

From where do all preganglionic nerve fibers of the sympathetic nervous system arise?

Answer 52

Thoracic and lumbar regions of the spinal cord

Question 53

Which nervous system transmits only excitatory signals to effector cells?

Answer 53

Somatic nervous system

Question 54

Which efferent pathway has a single nerve fiber extending from the CNS to effector?

Answer 54

Somatic

Question 55

Where are the cell bodies of sympathetic preganglionic fibers located in the spinal cord?

Answer 55

Lateral gray horn

Question 56

Which nervous system has two nerve fibers connecting the CNS to an effector?

Answer 56

Autonomic

Question 57

The division of the ANS that has relatively short preganglionic fibers and long postganglionic fibers is which division?

Answer 57

Sympathetic

Question 58

Which describes a preganglionic neuron in the ANS?

Answer 58

It has its cell body in the spinal cord or the brainstem and its axon terminates in a ganglion

Question 59

Which type of neurons make up the adrenal medulla?

Answer 59

Postganglionic sympathetic

Question 60

The nerves of the sympathetic nervous system arise from which regions of the spinal cord?

Answer 60

Thoracic Lumbar

Question 61

The division of the ANS that develops from the same embryonic tissue as the adrenal medulla is the ________ division.

Answer 61

sympathetic

Question 62

Regarding the length of fibers, the parasympathetic nervous system has ______ preganglionic fibers and ______ postganglionic fibers.

Answer 62

long, short

Question 63

Choose all the regions of the CNS that the nerves of the parasympathetic nervous system arise from.

Answer 63

Sacral division of spinal cord Brainstemc

Question 64

Within the ANS, the effects of the ______ division are often general and widespread, while in the _______ division the effects are more specific and local.

Answer 64

sympathetic, parasympathetic

Question 65

What is the alternative name for the craniosacral division of the ANS?

Answer 65

Parasympathetic division

Question 66

The ganglia of the sympathetic division are located ______.

Answer 66

near the spinal column

Question 67

The neurotransmitter ______ binds to cholinergic receptors.

Answer 67

acetylcholine

Question 68

The sympathetic division of the ANS is also called the ______ division as it arises from the thoracic and lumbar regions of the spinal cord.

Answer 68

thoracolumbar

Question 69

The division of the ANS that develops from the same embryonic tissue as the adrenal medulla is the __________ division.

Answer 69

sympathetic

Question 70

Which receptors bind to ACh?

Answer 70

Cholinergic

Question 71

The nerves of the sympathetic nervous system arise from which regions of the spinal cord?

Answer 71

Lumbar Thoracic

Question 72

Which type of receptor can either be inhibited or excited by the binding of acetylcholine?

Answer 72

Muscarinic

Question 73

What are two receptors that bind norepinephrine?

Answer 73

Alpha-adrenergic Beta-adrenergic

Question 74

What is the alternative name for the craniosacral division of the ANS?

Answer 74

Parasympathetic division

Question 75

The neurotransmitter ______ binds to cholinergic receptors.

Answer 75

acetylcholine

Question 76

What effect does the parasympathetic system have on the respiratory system?

Answer 76

Bronchoconstriction

Question 77

Which receptors are cholinergic receptors that are found at the synapses of all autonomic ganglia, on cells of the adrenal medulla, and at neuromuscular junctions?

Answer 77

Nicotinic

Question 78

Receptors for epinephrine and norepinephrine are called _________ receptors.

Answer 78

adrenergic

Question 79

Choose all the regions of the CNS that the parasympathetic division of the ANS arise from.

Answer 79

Brain Sacral spinal cord

Question 80

Choose all that are effects of the parasympathetic division on the digestive system.

Answer 80

Increased gastric motility Increased pancreatic enzyme secretion Increased gastrointestinal secretion

Question 81

The type of innervation that refers to the fact that many structures in the body are innervated by nerve fibers from both the sympathetic and parasympathetic divisions of the ANS is called __________ innervation.

Answer 81

dual

Question 82

The neurotransmitter norepinephrine binds to ______ receptors.

Answer 82

adrenergic

Question 82

The neurotransmitter norepinephrine binds to ______ receptors.

Answer 82

adrenergic

Question 83

What is the alternative name for the craniosacral division of the ANS?

Answer 83

Parasympathetic division

Question 84

Which division of the ANS causes a decrease in gastrointestinal secretions, pancreatic enzymes, and pancreatic insulin?

Answer 84

Sympathetic

Question 85

An organ that receives both sympathetic and parasympathetic fibers is said to have what?

Answer 85

Dual innervation

Question 86

Which receptors are cholinergic receptors that are found at the synapses of all autonomic ganglia, on cells of the adrenal medulla, and at neuromuscular junctions?