Bio 3301 Test 1

Front 1

A change in a membrane potential from +30 mV to -70 mV is an example of

Back 1

repolarization

Front 2

A threshold potential is

Back 2

the point at which there is an explosive increase in Na+ or Ca2+ permeability

Front 3

Graded potentials

Back 3

are local changes in membrane potential that occur in varying degrees of magnitude, and serve as short-distance signals

Front 4

The rising phase of the action potential is due to

Back 4

sodium influx

Front 5

Myelinated axons conduct impulses much faster because

A. The myelin insulates the axon
B. Channels only have to open at the nodes
C. Voltage is not lost along myelinated areas
D. Saltatory conduction occurs
E. All of these

Back 5

E. All of these

Front 6

At the peak of an action potential:

Back 6

The concentration gradient for K+ tends to move this ion out of the cell, and K+ permeability greatly increases

Front 7

The absolute refractory period

Back 7

refers to a period when the membrane cannot undergo another action potential and places an upper limit on the frequency with which a neuron can conduct action potentials

Front 8

Sequence the following events correctly.
1. Neurotransmitter diffuses across cleft
2. Calcium induces exocytosis of neurotransmitter
3. Permeability of postsynaptic membrane altered
4. Ion channels open
5. Neurotransmitter binds to receptor

Back 8

2,1,5,4,3

Front 9

In divergence

Back 9

An axon branches to synapse with many cells so that activity in one neuron influences the excitability of many other cells

Front 10

The nodes of Ranvier are

Back 10

breaks in the myelin covering

Front 11

Drugs may influence synaptic transmission by
A. altering the formation of neurotransmitters
B. blocking neurotransmitter reuptake
C. blocking receptors
D. blocking channels
E. all of these

Back 11

E. all of these

Front 12

The normal sequence of structures activated for signal transmission and response in the body is

Back 12

receptor->afferent neuron->interneuron->efferent neuron->effector

Front 13

Afferent neurons

Back 13

transmit messages to the spinal cord

Front 14

Which type of cell lines the ventricles of the brain?

Back 14

ependymal cells

Front 15

Which of the following is not a function of astrocytes?

Back 15

Line the internal cavities of the brain and spinal cord

Front 16

Cerebrospinal fluid

Back 16

is formed by the choroid plexus

Front 17

The arachnoid mater is

Back 17

a delicate, richly vascularized meningeal layer that is "cobwebby" in appearance

Front 18

The region of the brain that is the oldest in evolutionary development is the

Back 18

brain stem

Front 19

The sense of body position is

Back 19

proprioception

Front 20

Most of the cranial nerves originate from the

Back 20

brain stem

Front 21

The peripheral nervous system includes

Back 21

24 cranial nerves

Front 22

Which of the following is a monosynaptic reflex?

Back 22

stretch reflex

Front 23

Receptors

Back 23

exist that are specific for every modality in the environment, and when stimulated enough may cause Na+ channels in the afferent neuron membrane to open

Front 24

Receptor potentials

Back 24

are graded potentials

Front 25

Polymodal nociceptors

Back 25

activate the slow pain pathway

Front 26

The smaller the receptive fields in a region, the

Back 26

greater the density of receptors in the region and greater the acuity in the region

Front 27

Endorphins and enkephalins

Back 27

are endogenous morphine-like substances, important in the body's natural analgesic system

Front 28

Select the incorrect statement about slow pain

Back 28

It is carried by large, myelinated A-delta fibers

Front 29

The retina

Back 29

contains the photoreceptors

Front 30

During accommodation for near vision, the

Back 30

lens becomes stronger

Front 31

The blind spot

Back 31

is the point on the retina at which the optic nerve leaves and blood vessels pass through

Front 32

Which of the following is the proper sequence of retinal processing?

Back 32

rods and cones - bipolar cells - ganglion cells

Front 33

Vitamin A deficiency causes

Back 33

poor night vision

Front 34

The pitch of sound

Back 34

is determined by the frequency of vibrations of air molecules

Front 35

Fluid movement in the cochlea causes

Back 35

displacement of the round window, which dissipates pressure

Front 36

The auditory cortex is in the ________ lobe of the cerebral cortex

Back 36

temporal

Front 37

Actual conversion of sound vibrations to nerve impulses occurs in the

Back 37

cochlea

Front 38

Sour tastes represents stimuli caused by

Back 38

acids

Front 39

Olfactory receptors
A. are specialized endings of afferent neurons, not separate cells
B. when stimulated send impulses both to the limbic system for coordination between smell and behavior and to the thalamus and cortex for perception of smell
C. are replaced about every two months
D. are located in the olfactory mucosa
E. all of these

Back 39

E. all of these

Front 40

The structure associated with pheromonal reception is

Back 40

vomeronasal organ

Front 41

The autonomic nervous system is

Back 41

the involuntary branch of the peripheral nervous system's efferent division

Front 42

Which is not a characteristic of sympathetic pathways?

Back 42

Preganglionic fibers release norepinepherine

Front 43

Postganglionic autonomic fibers

Back 43

have numerous varicosities that simultaneously release neurotransmitter over a large area of the innervated organ rather than on single cells

Front 44

Select the incorrect statement about the parasympathetic nervous system

Back 44

It inhibits all cardiac muscle and smooth muscle

Front 45

Sympathetic stimulation _____ heart rate and ______ the motility in the digestive tract

Back 45

increases; decreases

Front 46

Nicotinic receptors

Back 46

respond to ACH released from sympathetic and parasympathetic preganglionic fibers

Front 47

Acetylcholinesterase

Back 47

inactivates a neurotransmitter

Front 48

Which type of receptor binds to norepinephrine on cardiac muscle, thus increasing cardiac activity?

Back 48

beta-1

Front 49

Select the correct statement about the neuromuscular junction

Back 49

it is always excitatory

Front 50

What would occur is ACh was not removed from the nicotinic receptors on skeletal muscle cells?

Back 50

The cell would remain contracted until fatigued, and sodium would continue to move into the cell causing excitation