Exam 2 - Nervous, Sensory, & Immune Systems

Question 1

An inhibitory postsynaptic potential (IPSP) occurs in a membrane made more permeable to

Answer 1

potassium ions

Question 2

When several EPSPs arrive at the axon hillock from different dendritic locations, depolarizing the postsynaptic cell to threshold for an action potential, this is an example of

Answer 2

spatial summation

Question 3

A neuron has a membrane potential of -70 mV, a threshold of -40 mV, and equilibrium potentials for K, Cl and Na of -90 mV (EK), -50 mV (ECl) and +60 mV (ENa), respectively. To generate an action potential in this cell, which of the following channels would you have to open?

Answer 3

Na channel

Question 4

What factors determine the direction of movement of ions across a biological membrane?

Answer 4

both membrane potential and concentraton gradient

Question 5

All action potentials are preceded by graded potentials.

Answer 5

True

Question 6

For a typical neuron like that shown, in what zone would you expect to find the myelin sheath?

Answer 6

I cant upload the pic but if the neuron looked like O—-K it’d be in the — part

Question 7

In an action potential, which of the following events happens first?

Answer 7

voltage-gated Na+ channels open

Question 8

In what direction would K flow in a cation selective channel that is opened by a ligand?

Answer 8

Out of the cell

Question 9

The equilibrium potential (EK) for K+ ions in a normal neuron is -92 mV and the resting membrane potential (VM) is -70 mV. If K+ channels in this neuron were to open, what would happen?

Answer 9

K+ ions would move out of the cell and the cell would hyperpolarize

Question 10

The typical stimulus that activates a mechanosensitive channel is:

Answer 10

membrane stretch

Question 11

Which event represents the physiological basis for the THRESHOLD?

Answer 11

opening of voltage-gated Na+ channels

Question 12

The detection of pitch (frequency of sound) is generally most dependent upon the physical properties of what specific structure?

Answer 12

basilar membrane

Question 13

The protein that physically interferes with the binding between actin and myosin at rest is

Answer 13

tropomyosin

Question 14

In phototransduction, what is most directly responsible for the dark current?

Answer 14

Na+ ions moving in through the cGMP-gated channels

Question 15

This structure carries action potentials deep into the interior of skeletal muscle cells. It is called a

Answer 15

t-tubule

Question 16

Which of the following is the correct sequence that occurs during the excitation and contraction of a muscle cell?
[1] Tropomyosin shifts and unblocks the cross-bridge binding sites.
[2] Calcium is released and binds to the troponin complex.
[3] Transverse tubules depolarize the sarcoplasmic reticulum.
[4] The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP.
[5] An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane.

Answer 16

5,3,2,1,4

Question 17

Sound energy is transferred from the tympanic membrane to the oval window by the

Answer 17

ossicles

Question 18

When a vertebrate photoreceptor responds to light, what is the cellular response?

Answer 18

the photoreceptor hyperpolarizes and releases less neurotransmitter

Question 19

As the stapes pushes on the oval window, fluid waves travel down the cochlea causing vibrations in specific regions of the basilar membrane, which in turn leads to activation of specific hair cells in the organ of Corti. Which of the following statement is true about this process?

Answer 19

the movement of the basilar membrane pushes the hair cells against the tectorialmembrane

Question 20

In terms of its functional role in taste (nutrient detection vs. toxin avoidance), which of the following basic tastes is unlike the other three?

Answer 20

bitter

Question 21

this one is too long but it’s asking about the properties of rods and cones

Answer 21

sorry :|

Question 22

Muscle contraction is controlled in part by a rise in Ca2+ in the sarcoplasm. Where does this Ca2+ come from?

Answer 22

from the sarcoplasmic reticulum via Ca2+ release channels

Question 23

Which of the following is considered a first line of defense against pathogens?

Answer 23

acidic secretions from the nasal cavity

Question 24

Why might it be a bad idea to take aspirin to reduce a moderate fever?

Answer 24

B and T cells are more active at high temperatures

Question 25

An autoimmune disease is one is which:

Answer 25

your body’s immune system begins to attack its own tissues

Question 26

Which of the following differentiates T cells and B cells?

Answer 26

T cells but not B cells can directly attack and destroy invading pathogens

Question 27

What effect do the perforins on pathogenic bacteria?

Answer 27

they lead to the formation of pores in bacteria, effectively killing them

Question 28

The cells in the immune system that have the greatest phagocytic activity are the _____________.

Answer 28

macrophages

Question 29

Natural killer cells are considered part of

Answer 29

innate immunity

Question 30

Which of the following cell types directly interacts with and kills infected or cancerous cells?

Answer 30

Cytotoxic T cells