NP1A

Question 1

Neurons are the building blocks of circuits, like segments of wire that can be connected in multiple ways to drive….(4 things)… and coordinate these responses with sensory input

Answer 1

Motor function
Release hormones
Regulate immune functions
Metabolic functions

Question 2

The __________ is a long extension of the neuron cell body

Answer 2

Axon

Question 3

The junction between circuit components is called the _________

Answer 3

Synapse

Question 4

The __________ may be located at one end, receiving signals on processes known as dendrites

Answer 4

Cell body

Question 5

_________ allow input from many different circuits

Answer 5

Dendrites

Question 6

The axon varies in ______ and can be as long as several feet

Answer 6

Lenght

Question 7

How do we transmit a signal over the length of the cell?

Answer 7

Establishing a charge across the plasma membrane (i.e. create polarized membranes). Then trigger depolarization on one end of the cell.
Depolarization will spread as a wave over the length of the axon and will trigger release of neurotransmitters upon reaching the end of the axon.

Question 8

How do we establish a membrane charge?

Answer 8

Establish high intracellular concentrations of K+ using ion pumps, but then let some of that K+ leak out of the cell, down its concentration gradient, through small channels that le K+ pass but not accompanying negatively charge molecules that normally balance the charge. These negatively charged molecules are larger (proteins). The result is excess of negative charge on the inner aspect of the membrane and an excess of positive charge on the outside. The membrane charged and is said to have a resting potential.

Question 9

The resting potential is

Answer 9

-90 mV

Question 10

__________________ establishes the intracellular concentration of K+ by exchanging +

Answer 10

ATP-dependent Na+ K+ pump

Question 11

Two ______ are brought in and three ______ are from the cell

Answer 11

K+ , Na+

Question 12

This pump requires ATP and defines the energy requirements of nervous system function

Answer 12

ATP-dependent Na+ K+ pump

Question 13

_____________ allow a small amount of K down its concentration gradient, leaving the large behind.

Answer 13

Potassium leak channels

Question 14

(True/False) Potassium leak channels allow extracellular Na+ to enter

Answer 14

False, leak channel does not allow extracellular Na+ to enter

Question 15

We initiate _______________ by allowing extracellular Na to flow back into the cell, down its concentration gradient, eliminating the negative charge. The process is know as “initiating an action potential”

Answer 15

Depolarization

Question 16

The sodium-potassium pump is initially open on the ______________ side of the cell

Answer 16

intracellular

Question 17

It is common for many cells to have far more ____________ leakage channels than __________ leakage

Answer 17

potassium, sodium

Question 18

Positive potassium ions that travel out of the cell contribute to a more ___________ charge inside the cell

Answer 18

negative

Question 19

Neurons have a Na+ gate that is closed when the membrane voltage is -90 to -50 mV, but above -50 mV the gate pops open, allowing Na+ to enter along its concentration gradient. The gate is thus known as a __________________

Answer 19

voltage gated Na channel

Question 20

What causes the change in a resting potential of -90 mV to the -50 mV (more positive) that causes the voltage-gated Na channel to open?

Answer 20

specialized nerve endings in skin, joints, and in visceral organs elicit pain responses to mechanical, chemical and thermal insults, and these insults have the effect of reducing membrane charge to the point of activating (opening) the voltage gated Na channels

Question 21

__________________ can reduce membrane charge to elicit an action potential

Answer 21

Neurotransmitters

Question 22

The __________ charge causes the opening of voltage-gated Na channels in adjacent areas such that the depolarization spreads as a wave across the cell

Answer 22

positive

Question 23

How do we repolarize so that we can send another signal? (three steps)

Answer 23

close the gate that is letting Na in, let more K+ out of the cell down its concentration gradient (and do it fast), and re-establish the high intracellular K+ and low intracellular pump and action of the K+ leak channels

Question 24

Neurons require abundant ____________ to support ATP production

Answer 24

oxygen

Question 25

___________________ is the type of glycolysis occurring in the presence of oxygen

Answer 25

aerobic glycolysis

Question 26

Neurons are dedicated to ____________ because it gives you maximum yield of energy production from glucose

Answer 26

aerobic glycolysis

Question 27

Neurons utilize blood glucose almost exclusively for their energy demands and do not require ____________ for glucose uptake

Answer 27

insulin

Question 28

_____________ and ____________ affect neuronal function at a time when disturbances in other cell types is not apparent

Answer 28

hypoglycemia, hypoxemia

Question 29

An abnormally low concentration of oxygen in the blood

Answer 29

hypoxemia

Question 30

______________ (increased/decreased) extracellular K+ will diminish the function of K+ leak channels because we don’t have a steep concentration gradient (inside vs outside), and this is key to establishing a resting potential

Answer 30

increased

Question 31

_______ stabilizes the outer gate of the voltage-gated sodium channel so that it stays closed when voltages are in the -90 to -50 mV range. Reduction in serum _______ by 50% can cause the gate to be prone to inappropriate opening, creating a hyperexcitable state

Answer 31

Ca++

Question 32

Generation of ATP for _________________ is the predominant metabolic demand placed upon neurons

Answer 32

Sodium-potassium pumps

Question 33

Severe hypoglycemia causes altered neuronal function. Which of the following is the basis for a neuron’s susceptibility to the adverse effects of hypoglycemia?

Answer 33

sodium-potassium pump

Question 34

What is primarily affected by the drop in Ca++ levels, giving rise to tetany?

Answer 34

voltage gate sodium channels

Question 35

What triggers depolarization?

Answer 35

voltage gate sodium channels

Question 36

Myelin sheaths are made by:

Answer 36

• Oligodendrocytes in CNS
• Schwann cells in PNS