The Nervous System

Question 1

Ependymal cells

Answer 1

Line the ventricles of the brain and produce cerebrospinal fluid

Question 2

Microglia

Answer 2

A phagocyte that ingest and break down waste products and pathogens in the CNS

Question 3

Oligodendrocytes and Schwann cells

Answer 3

Myelinating cells in the CNS and PNS respectively

Question 4

Voltage of the resting potential

Answer 4

-70 mV

Question 5

How the negative potential inside the membrane during the resting phase is set

Answer 5

Na+/K+ active pump

Greater permeability of K+ channels, making K+ leave the membrane

Question 6

Approximate threshold voltage for an action potential

Answer 6

-40 mV

Question 7

Na+ Voltage gated channel opening frame

Answer 7

Very short

Open at the threshold and then close around +35 mV which is the point when K+ channel slowly opens to rush out

Question 8

During an action potential, is it electrically and chemically favorable for the Na+ to rush into the membrane?

Answer 8

YES, electrically excess positive charge built up outside the membrane are attracted to the negative inside the cell.

Chemically, there is a higher concentration of Na+ outside the cell than the inside.

Question 9

What’s the purpose of action potential moving down the axon in wave-like fashion with a refractory period preceding the activated segment?

Answer 9

Allows the impulse to propagate in one direction

Question 10

What is the speed of the conduction dependent on?

Answer 10

Resistance increase with Length and decrease in Cross Sectional AREA (REPLAY)

Question 11

How does one increase the action potential?

Answer 11

Increase the frequency not the intensity

Question 12

How are are the NT’s in the vesicles of a pre synaptic cell released?

Answer 12

Ca2+ binding stimulates exocytosis

Question 13

What are some post synaptic responses?

Answer 13

Ligand gated cell that causes depolarization or hyper polarization

G-coupled protein receptor: change in cAMP concentration or influx of Ca2+

Question 14

Ways NT’s are cleared in the synapse

Answer 14

1) enzyme inhibitor
2) transporter channel back into the pre synaptic cell
3) diffuse out of the synaptic cleft (nitrous oxide is a good example that causes this)

Question 15

Inter neurons

Answer 15

Reflexive behaviors

Question 16

Reflex

Answer 16

Only at the level of the spinal cord not the brain

Question 17

Spinal cord: white and grey matter composition

Answer 17

White matter outside and grey matter inside

Question 18

Brain: White and grey matter composition

Answer 18

Grey matter outside, white matter inside

Question 19

Preganglionic and postganglionic neurons

Answer 19

Neurons working together just outside the spinal cord to convey the message to the effector cells

Question 20

NT’s used in parasympathetic and sympathetic nervous system

Answer 20

Parasympathetic: ACh only

Sympathetic: ACh and NE in the postganglionic

Question 21

Monosynaptic reflex

Answer 21

Directly from sensory to motor neuron

Simple sense and react mechanism - knee jerk

Question 22

Polysynaptic reflex

Answer 22

Sensory -> inter neuron -> motor

Interneuron synapses with other motor neurons for additional function.

For example, maintaining balance during the reflexive behavior.

Question 23

Astrocyte

Answer 23

Star shaped cell that reaches across all neurons with his legs and nourish them, and form the blood-brain barrier