Intro to neurones, nerve conduction and synaptic transmission

Question 1

Receive inputs from other neurones and convey graded electrical signals passively to the soma

Answer 1

Dendrites

Question 2

Perikaryon

Answer 2

Soma

Question 3

Synthetic and metabolic centre. Contains the nucleus, ribosomes, mitochondria and endoplasmic reticulum (ER; rough ER is Nissl substance). Integrates incoming signals that are conducted passively to the axon hillock

Answer 3

Soma (perikaryon)

Question 4

Contains the nucleus, ribosomes, mitochondria and ER

Answer 4

Soma (perikaryon)

Question 5

Site of initiation of the “all or none” action potential

Answer 5

Axon hillcock and initial segment

Question 6

Conducts output signals as action potentials to other neurones (or other cells).

Mediates transport of materials between the soma and presynaptic terminal (anterograde direction) and vice versa (retrograde direction )

Answer 6

Axon

Question 7

Which direction is it if soma –> presynaptic terminal

Answer 7

Anterograde direction

Question 8

What is retrograde direction?

Answer 8

From presynaptic terminal –> soma

Question 9

Which viruses exploit retrograde transport to infect neurones?

Answer 9

Herpes, polio, rabies

Question 10

Site of protein synthesis

Answer 10

Rough ER / Nissl bodies

Question 11

• Conducts output signals as action potentials to other neurones (or other cells)
• Mediates transport of materials betwen the soma and presynaptic terminal

Answer 11

Axon

Question 12

Example of unipolar neurone

Answer 12

Peripheral autonomic neurone

Question 13

Example of pseudounipolar neurone

Answer 13

Dorsal root ganglion neurone

Question 14

Example of bipolar neurone

Answer 14

Retinal bipolar neurone

Question 15

Example of multipolar neurone

Answer 15

Lower motor neurone

Question 16

What staining method allows visualisation of individual neurones?

Answer 16

Golgi staining method

Question 17

Where might you find local interneurones?

Answer 17

E.g. between neurones in the CNS

Question 18

Where might you find projection neurones?

Answer 18

E.g. from dorsal horn of the spinal cord to brain structures

Question 19

Golgi type I

Answer 19

Short axon

Question 20

Golgi type II

Answer 20

Long axon

Question 21

What allows electrical signals to be conducted over large distances without decaying?

Answer 21

Action potentials

Question 22

How can you decrease axoplasm resistance?

Answer 22

By increasing the axon diameter

Question 23

How can you increase membrane resistance?

Answer 23

By adding an insulating material (myelin)

Question 24

Name a demylineating disorder affecting the CNS

Answer 24

Multiple sclerosis

Question 25

Name a demylineating disorder affecting the PNS?

Answer 25

Guillan-Barre

Question 26

Name 3 different types of synapse

Answer 26

Axodendritic Axosomatic Axoaxonic

Question 27

Most common type of synapse

Answer 27

Axodendritic

Question 28

Excitatory transmitter in the CNS

Answer 28

Glutamate

Question 29

What is the overshoot?

Answer 29

When the polarity becomes positive (briefly)

Question 30

Glutamate activates cation or anion selective channels?

Answer 30

CATION (Na+) | -results in DEpolarising response

Question 31

GABA activates which type of channels?

Answer 31

ANION (Cl-) -results in hyperpolarising response (GABA also called glycine)

Question 32

What is spatial summation?

Answer 32

Many inputs converge upon a neurone to determine its output

Question 33

What is temporal summation?

Answer 33

A single input may modulate output by variation in action potential frequency of that input

Question 34

These mediate fast neurotransmission

Answer 34

Ionotropic ligand gated ion channels

Question 35

These mediate slow neurotransmission

Answer 35

G-protein coupled receptors

Question 36

Where are the enzymes synthesised? and what do these enzymes do? (this is for making AMINO ACID/AMINE neurotransmitter)

Answer 36

Synthesised in the cell body and are transported to the presynaptic terminal by axoplasmic transport These enzymes then make neurotransmitters at the terminal

Question 37

What do transmitter proteins do?

Answer 37

Concentrate the neurotransmitter

Question 38

Difference in products released from synaptic and secretory vesicles?

Answer 38

Amino acids and amines are released from synaptic vesicles Peptides are released from secretory vesicles