Nerves

Question 1

What are the different types of glia cells found in the CNS?

Answer 1

Olgiodendrocytes (for myleination), astrocytes (blood brain barrier, physical support), epemdym (lining the ventricles and the central canal p.

Question 2

What are the different types of glia found in the PNS?

Answer 2

Schwann cell (myleinate a single axon), satilliite cells which provide the physical support for neurones, and mircoglia, which have an immune and inflammatory function.

Question 3

What is the percentages of glia and neurones found in the body?

Answer 3

90% glia, 10% neurones

Question 4

What are the two key parts of an neurone?

Answer 4

The cell body and the axon

Question 5

What are some of the cell histological features of a cell body?

Answer 5

The nucleus and nueclous, golgi appartus which packages transmitters into vesicles and nissi substance for protein synthesis.

Question 6

What is a collection of cell bodies referred to as?

Answer 6

The grey matter in the CNS, and a ganglion in the PNS

Question 7

What are some of the features of axons?

Answer 7

In myelinated axons , a Schwann cell wraps itself around the axon about 100 times, level of myelination varies between neuronal types, myelinated axons tend to be thicker (greater than 1um will conduct faster with a myelin sheath whereas less than 1 um will conduct slower with a myelin sheath.

Question 8

What are the nodes of ranvier?

Answer 8

This are the gaps between the neurone where polarisation occurs in nerve cells.

Question 9

What are the different diseases that can result from demyelination?

Answer 9

Multiple sclerosis, polyneuropathies, diabetes, gullian bare.

Question 10

What are the different envelopes in the PNS?

Answer 10

The epineurium which ensheathes the entire nerve and has interfascular attachments, the perineurium which ensheathes a nerve fascicle, and the endonerium which ensheathess a single cell axon.

Question 11

What are the membranous envelopes on the CNS?

Answer 11

Dura matter, archanoid matter, pia matter.

Question 12

How does nerve severing result in wallerian degeneration?

Answer 12

The proximal section of a nerve seals up to prevent leakage and a nerve stump is formed, which cuts of the distal section from nutrients leading it to die, and so the process of wallerian degeneration is nessediated.

Question 13

How does nerve severing result in wallerian regeneration?

Answer 13

The proximal section sells and the cell body suddenly swells up with increased contents, the nucleus is displaced from the centre to the side margins, known as chromatolysis and then the axon usually regrows by wallerian regeneration.

Question 14

What are the two types of nerve cells?

Answer 14

Neurones and glia

Question 15

What are some key features of the central nervous system?

Answer 15

Contains the brain (cranium) and the spinal cord (vertebral column) both pf which are incased by bone, and suspended in cebrospinal fluid

Question 16

What are some key features of the peripheral nervous system ?

Answer 16

Connects the CNS to sensory or target organs, and contains different parts including the enteric nervous system, the ganglia, the axons of spinal nerves and the axons of cranial nerves.

Question 17

What are some key features ot he somatic efferent system?

Answer 17

They are undeveloped at birth and fully developed at puberty, the efferent neurone terminates on the effector organ and 1 neurone carries the output in a spinal or cranial location.

Question 18

What are the key features of the autonomic nervous system?

Answer 18

The ancient control system representing automatic control, it subserves fundamental life processes and help to to maintain a constant internal environment. Exhibits reciprocal control.

Question 19

What are the key structural features of the autonomic nervous system?

Answer 19

Always 2 neurones in a set, one has the body in the CNS and one has the cell body in the PNS, the first is the Pregangloic neurone which does not supply the organs directly and the the second is the post-ganaglonoic neurone which does supply the organs directly. Pregangloic is usually myelinated whereas the post ganaglonoic is not usually myelinated.

Question 20

What are the two forms of autonomic control and their similarities and differences?

Answer 20

The parasympathetic and the sympathetic nervous system, which have a fairly common structure but different neurotransmitters

Question 21

What area of the spinal chord is involved in the sympathetic nervous system?

Answer 21

The 12 thoracic segments and the first 2 lumbar segments

Question 22

What are the key structural features of the thoraic segment of the spinal chord?

Answer 22

The dorsal horn, the ventral horn and the lateral horn

Question 23

What response is the sympathetic nervous system usually involved in?

Answer 23

The fight ofr flight response of stressful situation

Question 24

What are the relative lengths of the two neurones in the sympathetic nervous system?

Answer 24

The proximal to the spinal cord neurone is shorter, while the distal to the spinal cord neurone is longer.

Question 25

What neurotransmitter do the Pregangloic neurones of the sympathetic nervous system (found in the spinal cord) use?

Answer 25

Cholinergic synapse.

Question 26

What neurotransmitter do the post ganglionic neurones of the sympathetic nervous system use?

Answer 26

Noradrenaline (with some nitoonic receptors)

Question 27

Where are the cell bodies of the Pregangloic sympathetic neurones found?

Answer 27

The thoraco-lumbar cord.

Question 28

What re the three ways that the neurones may terminate?

Answer 28

May synapse at a level corresponding to that of origin, may synapse at a level different to that of origin or may synapse in the para vertebral chain in the case of splanchnic nerves.

Question 29

What is the action of the parasympathetic nervous system?

Answer 29

Cranio sacro outflow, so from the cranial nerves(occulmotor, facial vagus) and from the sacral spinal cord.

Question 30

What are the relative lengths of the pre-gangloic and post-ganglionic nerves of the parasympathetic nervous system?

Answer 30

Long Pregangloic fibres and short post gangloic fibres. (Post gangloic within the walls of effector organs)

Question 31

What is the neurotransmitter used at the Pregangloic synapse of the parasympathetic nervous system?

Answer 31

Acetylcholine

Question 32

What is the neurotransmitter used at the post cholinergic synapse of the parasympathetic nervous system?

Answer 32

Acteylcholine