Exam 4 Practice Questions

Question 1

When a neuron is not receiving stimuli from other neurons, what is the approximate voltage across the plasma membrane?

Answer 1

-70mV

Question 2

Where are action potentials initiated?

Answer 2

axon hillock

Question 3

The threshold for initiating an action potential is -55mV. Why?

Answer 3

voltage gated sodium channels open

Question 4

Adenosine is a neurotransmitter that is used in synapses of neurons that cause drowsiness. Caffeine prevents adenosine from binding to its receptors in the synapse.
Caffeine causes:

Answer 4

fewer graded potentials

Question 5

At a dendritic synapse, the neurotransmitter GABA is bound by its receptor, allowing chloride (Cl-) to flow into the cell. This shifts the membrane potential from -70 mV to -82 mV. This is:

Answer 5

an inhibitory graded potential

Question 6

A neuron binds neurotransmitters at three different dendrites that cause graded potentials of +10, -15, and -20 mV. Will the neuron initiate an action potential?

Answer 6

No

Question 7

Jimmy takes a medication that acts by increasing the level of serotonin in the synaptic cleft. In neurons with serotonin receptors, this medication will cause:

Answer 7

more graded action potentials in the postsynaptic neuron

Question 8

Where is cerebrospinal fluid produced?

Answer 8

the choroid plexus

Question 9

How does the cerebral cortex communicate with the brain stem?

Answer 9

projection fibers

Question 10

The blood brain barrier is composed of blood vessel endothelial cells and:

Answer 10

astrocytes

Question 11

I am a region of the brain that is important for memory. Who am I?

Answer 11

hippocampus

Question 12

Gamma aminobutyric acid, or GABA, is a key inhibitory neurotransmitter in CNS neurons. GABA binds its receptor and inhibits the production of action potentials in the postsynaptic neuron. GABA causes:

Answer 12

hyper polarizing graded potentials

Question 13

In an accident, a patient’s spinal cord is severed between the C2 and C3 cervical vertebra. This individual will most likely have:

Answer 13

quadriplegia

Question 14

A patient reports having full sensation in the left hand, but cannot close their fingers to make a fist. What is the most likely problem?

Answer 14

damage to the ventral horn of the spinal cord

Question 15

Tom isn’t paying attention in lab and accidentally touches liquid nitrogen(extremely cold), resulting in pain. This will activate what type of pain receptor?

Answer 15

nocicoreceptors

Question 16

A nociceptor receives stimuli resulting in several graded potentials. What determines whether the nociceptor generates an action potential to communicate with the spinal cord?

Answer 16

whether depolarization exceeds threshold

Question 17

The cell bodies of sensory neurons in the PNS are found in the:

Answer 17

dorsal root ganglion

Question 18

Efferent motor neurons will synapse with spinal cord neurons at

Answer 18

the ventral horn

Question 19

Which of the following regions have some ability to regenerate damaged neuronal axons?

Answer 19

peripheral sensory nerves

Question 20

Motor neuron disease (MND) is a set of neurodegenerative disorders that affects the ability of the nervous system to control voluntary muscles. Which regions of the nervous system may be damaged in MND patients?

Answer 20

all of the above: the primary motor cortex, the ventral horn of the spinal cord, & the peripheral motor nerves

Question 21

The optic nerve is classified as:

Answer 21

a cranial nerve

Question 22

During the patellar(knee-jerk) reflex, which of the following receives excitatory impulses?

Answer 22

the quadriceps

Question 23

Which of these effectors is not controlled by the autonomic nervous system?

Answer 23

skeletal muscle