L8 - Synapses

Question 1

Describe electrical synapses (spark) (5)

Answer 1

Gap junction

Bidirectional

Fast transmission (no delay)

1-3% transmission

Fight or flight

Question 2

What are electrical synapses made of?

Answer 2

2 connexions and each made up of 6 connexion subunits.

Pore 1-2 nm

Question 3

What kind of synapses are most common?

Answer 3

Chemical

Question 4

Chemical Synaptic Transmission – ‘soup’

Answer 4

Electrical-Chemical-Electrical

Question 5

Characteristics of the chemical synapse.

Answer 5

AP, Ca2 channels, synaptic vesicles, post receptor, cholinesterase, cleft (20-50nm)

Question 6

Vesicular release

Answer 6

1. Docking
2. Ca2 entry
3. Fusion
4. Recyling

Evolved once

Question 7

SNARE hypothesis

Answer 7

Proteins join together – very tight, lipid membranes close together despite positive phosphate groups

Calcium = tighter = increase probability of fusion of the membrane

Question 8

Spontaneous release of NT

Answer 8

Absence of Ca2

Ca2 increases the probability of NT release

Question 9

What is meant by Quantal

Answer 9

Nt realise equal

NT in each vesicle the same

1 quanta = amount of nt per vesicle

Question 10

How much quanta is released during AP-evokes epss

Answer 10

200 per AP

Question 11

3 toxins that interfere and how

Answer 11

Omega: Blocks Ca channels

Botulinum: Blocks NT release

A-bungarotoxin: Bind to ACh receptors

Question 12

Where does Botox come from and what does it do?

Answer 12

C. botulinum

Destroys SNARE protein

Block neuromuscular junction = paralysis

Question 13

Therapeutic uses of Botox

Answer 13

1. Excessive sweating
2. Muscle spasticity (CP and stroke)
3. Strabismus
4. Chronic migrane