Neural Physiology

Question 1

What are the 4 lobes of the brain

Answer 1

Frontal
Occipital
Temporal
Parietal
(Limbic)

Question 2

Name the 8 main parts of the axon

Answer 2

Soma
Cell Body
Dendrites
Axon Hillock
Myelin Sheath
Axon
Axon Terminal
Synapse Terminal

Question 3

What 3 things make up the soma

Answer 3

Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Golgi Apparatus

Question 4

Describe axoplasmic transport

Answer 4

Microtubules run down the length of the axon- anterograde and retrograde transport. The vesicles which have been packaged by the Golgi apparatus attach to motor proteins which move down the axon to the synapse.

Question 5

What is the resting membrane potential

Answer 5

-70mV

Question 6

How many Na for K etc

Answer 6

3Na in for 2K out

Question 7

Describe the action potential graph

Answer 7

 At -55, voltage gated Na channels open and flood into the cell. Depolarisation
o Doesn’t hit 55 nothing happens
 At +30, VG NA close, VG K open and K repolarises the cell
 Hyperpolarisation due to delay in closing of the cell
 Undershoot comes back up due to the Na/K pump

Question 8

What are electrical synapses

Answer 8

gap junctions, bio-directional so ions and small molecules can pass through

Question 9

Describe the what happens at a synapse

Answer 9

 Action potential arrives
 Ca enters cell via VG channels
 Acetylcholine expelled via exocytosis into synaptic cleft
 Ach binds on the post synaptic knob
 Sodium enters and generates AP
 Ach binds with AchE in the cleft and is broken down into choline and acetate
 Choline renters the pre-synaptic knob and can be used to form more Ach
 AP travels and can initiate the muscular contraction

Question 10

What are SNARE proteins

Answer 10

Protein complexes which bind to synaptic vesicles and cause them to fuse with the neuronal cell membrane, releasing ACh.

Question 11

Give 3 SNARE proteins

Answer 11

synaptobrevin, SNAP-25, and syntaxin.

Question 12

Describe the SNARE protein involvement with Botox

Answer 12

BoNT binds to the cell membrane and enters the neuron by endocytosis.
The light chain is translocated through the membrane and then cleaves SNARE proteins, blocking acetylcholine release. This paralyses the muscles.

Question 13

What are cholinergic neurons

Answer 13

all motor neurons in the spinal chord

Question 14

What is the equation for ACH formation

Answer 14

Acetyl CoA + Choline  Acetyl Choline (with choline acetyltransferase)

Question 15

Give examples of catecholaminergic neurons

Answer 15

dopamine, norepinephrine and epinephrine (are formed from tyrosine)

Question 16

What is the equation for serotonin formation

Answer 16

Tryptophan + 5-HTP  Serotonin (with tryptophan hydroxylase and decarboxylase)

Question 17

Give examples of amino adrenergic neurons

Answer 17

Glutamate (excitatory), Glycine and GABA (inhibitory)

Question 18

Describe the effect of cocaine on the synapse`

Answer 18

Dopamine is secreted, and causes a happy energised feeling. Cocaine blocks the dopamine transporter on the pre-synaptic knob, so dopamine cannot be reuptaken.

Question 19

Give 4 ways to measure neural intensity

Answer 19

• dynamometer
• electromyography
• magnetic stimulation
• electrical stimulation

Question 20

Describe a dynamometer

Answer 20

o Measures force or strength in newtons/newton meters

o Can give absolute or relative values

Question 21

Describe electromyography

Answer 21

o Records changes in electrical potential of the muscle

o Can do this intramuscularly or on the surface of the skin

Question 22

What is a motor evoked potential

Answer 22

A response to trans-cranial electrical stimulation, or magnetic brain stimulation followed by measurement of the compound muscle action potential (CMAP) of different muscles.

Question 23

What does MEP measurement allow

Answer 23

•	Excitability 
o	M-wave amplitude/area
•	Contractility
o	Twitch force
o	Time to peak twitch
o	Half relaxation times
o	Electromechanical delay
•	Voluntary Activation

Question 24

Define critical torque

Answer 24

Torque value at which things change during fatiguing contractions.