Nerve Transmission

Question 1

Clusters primarily composed of axons

Answer 1

CNS: Tract
PNS: nerve

Question 2

Glia

Answer 2

Smaller than neurons but more numerous

Don’t transmit info across long distances

Question 3

Astrocytes

Answer 3

Synchronize activity of neurons

Remove waste materials

Question 4

Microglia

Answer 4

Remove waste materials and microorganisms (viruses, fungi)

Question 5

Oligodendrocytes and Schwann cells

Answer 5

Build the myelin sheaths

Question 6

Radial glia

Answer 6

Glide migration of neurons and growth of their axons

Question 7

What protects the NS?

Answer 7

Skull (brain)
Backbone (spinal cord)
Meninges (membranes surrounding brain and spinal cord)

Question 8

What does a blood brain barrier do?

Answer 8

Prevents viruses as harmful chemicals from entering the brain
Stops large molecules and electrically charged molecules

Question 9

What passes the barrier?

Answer 9

ACTIVELY
Small uncharged molecules 
Water
Fat soluble molecules 
PASSIVELY
glucose 
Amino acids 
Certain vitamins

Question 10

Speed that neurons conduct info via electric impulses

Answer 10

1 meter/second to 100 m/s

Question 11

Explain resting potential (neurons)

Answer 11

Neurons more negative inside
Voltage difference
70MV (typical)

Question 12

4 interacting factors of resting potential

Answer 12

Homogenizing factors:
1. Concentration gradients
2. Electrical gradient 
These are counteracted by two properties 
3. Membrane permeability at rest
4. Sodium potassium pump

Question 13

Explain action potential

Answer 13

Response of a neuron to stimulation above a certain threshold
Prepares neuron to respond quickly
Results in depolarisation - neuron becomes less negative
Then returns to RP value (repolorization)

Question 14

What is the refractory period?

Answer 14

Immediately after action potential, another cannot happen

Question 15

What is absolute refractory period?

Answer 15

No action potential can be produced

Question 16

What is relative refractory period

Answer 16

Stronger than usual stimulus can produce action potential

Question 17

Synapse

Answer 17

Side at which info flows from one neuron to another

Question 18

Small gap between neuron has 3 main parts;

Answer 18

• presynaptic terminal
• synaptic cleft
• post synaptic neuron

Question 19

What are ionotropic receptions

Answer 19

Post synaptic receptors
Effect is fast and short
Glutamate and GABA
for vision, hearing

Question 20

What are metabotropic receptors?

Answer 20

Post synaptic receptor 
Effect is slow and long
NT activates G-protein 
This can bind to ion channels
Relevant for hunger, thirst, fear, anger

Question 21

Reuptake of NT?

Answer 21

NT is taken up and reused by presynaptic neuron

Question 22

What is temporal summation?

Answer 22

Depends of size, time and threshold of postsynaptic neuron

Question 23

What is spatial summation

Answer 23

Summation of several simultaneous EPSP

Question 24

Cocaine

Answer 24

Dopamine and norepinephrine agonist
Blocks their reuptake
Effects - euphoria, loss of appetite, insomnia and addiction

Question 25

Benzodiazepines?

Answer 25

Diazepam
GABA agonists increases binding of GABA
Effects - reduce anxiety, induce sleep and reduce seizures

Question 26

Clusters contain

Answer 26

CNS: nucleus
PNS: ganglion