CTR - 6 - RMP

Question 1

What is the path along a neuron?

Answer 1

Dendrite –> Cell Body –> Axon –> Nerve Terminals –> Synapse with postsynaptic cell

Question 2

Sensory neurons are usually __________.

Answer 2

Unipolar

Question 3

Motor neurons are ____________.

Answer 3

Multipolar

Question 4

Interneurons are _____________.

Answer 4

Multipolar

Question 5

Less, and longer dendritic spines = ____________

Answer 5

Mental retardation

Question 6

Mental retardation - spines

Answer 6

Less, and longer dendritic spines

Question 7

Epilepsy and malnutrition - spines

Answer 7

Thickening of dendritic spines / pinched inwards

Question 8

Thickening of dendritic spines / pinched inwards

Answer 8

Epilepsy and malnutrition

Question 9

Longer dendritic spines

Answer 9

Fragile X Syndrome / SIDS

Question 10

Fragile X Syndrome / SIDS - spines

Answer 10

Longer dendritic spines

Question 11

Where does protein synthesis occur in neurons?

Answer 11

Cell bodies

Question 12

Nerve axons contain _______ and_________.

Answer 12

Mitochondria and microtubules

Question 13

Rate of slow axonal transport. What is transported?

Answer 13

0.2-5mm / day

Material not rapidly consumed (enzymes, proteins)

Question 14

Rate of fast axonal transport. What is transported?

Answer 14

400 mm / day

Vesicles, mitochondria, removes waste (to cell body - lysosomes)

Question 15

Myelin allows speeds of ______?

Answer 15

150 m/s

Question 16

Most abundant ion in cells

Answer 16

K+

Question 17

Most abundant ion outside cells

Answer 17

Na+

Question 18

The body is in osmotic, chemical and electrical __________. Why?

Answer 18

Osmotic equilibrium - water moves between compartments

Electrical disequilibrium - Na+K+ pumps one positive charge out

Chemical disequilibrium - Na+K+ maintains high concentrations of Na+ outside and low K+ inside

Question 19

The body is electrically _______. But why is there unequal distribution of charge?

Answer 19

Electrically neutral.

But charge is separated at the membrane. Negative inside. Outside positive

Question 20

The cell membrane is a good ______.

Answer 20

Insulator

Question 21

What maintains the RMP? What does it create?

Answer 21

Na+ K+ pump - creates electrochemical gradients

Question 22

What is the equilibrium potential of Na+ and K+? What is the RMP? Explain.

Answer 22

Na+ = +60 mV
K+ = -90mV
RMP = -70 mV

Membrane is closer to K+ equilibrium potential as membrane is much more permeable to K+.

Question 23

What would happen without the Na+ K+ pump?

Answer 23

K+ and Na+ would move down their concentration gradients until chemical and electrical equilibrium was obtained - elimination of RMP

Question 24

How does lethal injection work?

Answer 24

Increased extracellular potassium - decreases K+ gradient –> increases potassium equilibrium potential (less negative) –> RMP approaches zero –> heart does not contract