Nervous System

Question 1

What does the nervous system comprise of?

Answer 1

Central nervous system

Peripheral nervous system

Question 2

What does the Central nervous system comprise of?

Answer 2

Brain

Spinal cord

Question 3

What does the Peripheral nervous system comprise of?

Answer 3

Somatic nervous system - voluntary

Autonomic nervous system - involuntary

Question 4

What are names given to nerves going to and from the central nervous system?

Answer 4

Efferent - away from the CNS (sensory neurone)
Afferent - toward the CNS (motor neurone)

E - Exit
A - Affinity

Question 5

What are some cells involved in the CNS?

Answer 5

Nerve cells - neurones (they are electrically active)

Supporting cells - neuroglia, glial cells

Question 6

What is a nerve?

Answer 6

A bundle of axons surrounded by connective tissue which binds them together

Question 7

What is the sensory neurone made up of? (in the direction of the nerve impulse)

Answer 7

Dendrites
Dendron
Soma (cell body) - in the middle
Axon
Branches of axon
Synaptic knob (terminal)

Potentially with myelin sheath and nodes of Ranvier

Question 8

What is the intermediate (multipolar) neurone or interneurone made up of?

Answer 8

Cell body in the middle

Axon and dendrites, with branches of axon and dendrites attached all around the cell body

Question 9

What is the motor neurone made up of? (in the direction of the nerve impulse)

Answer 9

Some (cell body) at the end, surrounded by dendrites
One large axon
Branches of axon
Motor end plate (terminal) - forms neuromuscular junction

Potentially with myelin sheath and nodes of Ranvier

Question 10

How to remember the direction of the nerve impulse?

Answer 10

Dendrites - dick in

Axon - away

Question 11

What do dendrites do?

Answer 11

Subdivisions of the dendron which transmit nerve impulses towards the cell body

Question 12

What does the Soma contain?

Answer 12

Nucleus

Large amounts of rough endoplasmic reticulum (for production of proteins and neurotransmitters

Question 13

What are the nodes of Ranvier?

Answer 13

Gaps between adjacent schwann cells where there is no myelin sheath

Question 14

Which neurone is faster myelinated or unmyelinated, why?

Answer 14

Myelinated is faster

The fatty sheath of myelin around the axon acts as a electrical insulator preventing action potentials forming
At the nodes of ranvier, a localised current can form, s the action potential can ‘jump’ from node to node = saltatory conduction

Question 15

How can neurones be classified by their actions?

Answer 15

Excitatory neurones - increase the activity of target cells
Common transmitter is glutamate

Inhibitory neurones - decrease the activity of target cells
Common transmitter is GABA (gamma-amino butyric acid)

Question 16

How is the neurone structurally organised?

Answer 16

The nucleus and the tract are in the CNS

The nerve and the ganglion are in the PNS

Question 17

What is the nucleus and the tract?

Answer 17

Nucleus - a collection of neuronal cell bodies in the CNS

Tract - a group of functionally related axons in the CNS

Question 18

What is the nerve and the ganglion?

Answer 18

Nerve - a bundle of axons in the PNS

Ganglion - a collection of cell bodies in the PNS (no longer a nucleus)

Question 19

What are glia cells in comparison to neurones?

Answer 19

Glia only have one ‘process’ whereas neurones have two (axons and dendrites)
Glia don’t carry action potentials, but do have a resting potential
Glia don’t have synapses

Question 20

What are the two catagories of glial cells?

Answer 20

Myelinating glial cells

Supporting glial cells

Question 21

What are the myelinating glial cells?

Answer 21

Schwann cells - provides myelin to neurones in the PNS

Oligodendrocytes - provides myelin to neurones in the CNS

Question 22

Whar are the supporting glial cells?

Answer 22

Astrocytes - transport nutrients to neurones, clean up brain ‘debris’, hold neurones in place
Satellite - Gives physical support to (sensory) neurones in the PNS
Microglia - ‘the immune cells of the brain’ clean up CNS debris (to prevent toxic build up)

Question 23

What is the somatic nervous system made up of?

Answer 23

Voluntary nervous system

Motor neurones (efferent)
Sensory neurones (afferent)

Question 24

What are some factors of the sensory neurone?

Answer 24

Lies within the PNS
Can be both un/myelinated
Afferent - towards the CNS
Neurotransmitter - glutamate

Question 25

What are some factors of the motor neurone?

Answer 25

Lies within the CNS
Heavily myelinated
Efferent - away from the CNS
Neurotransmitter - acetylcholine

Question 26

What is the autonomic nervous system made up of?

Answer 26

Involuntary controls: heart rate, blood pressure and gut movements

Sympathetic - fight or flight
Parasympathetic - rest and digest

Question 27

Describe the sympathetic structure?

Answer 27

Soma and dendrites at the end
Short preganglionic myelinated axon
Terminal closer to the CNS, with a synapse to a ganglion (acetylcholine transmitter to nicotinic receptor)
Long postganglionic axon, that branches extensively into multiple terminals with noradrenaline transmitter to the target/effector

Question 28

Describe the parasympathetic structure?

Answer 28

Soma and dendrites at the end
Long preganglionic myelinated axon
Terminal towards the target, with a synapse to a ganglion (acetylcholine transmitter to nicotinic receptor)
Short postganglionic axon, that branches minimally to one terminal with acetylcholine transmitter to the target/effector

Question 29

What is another element of the autonomic nervous system?

Answer 29

The enteric nervous system - is one of the main divisions of the ANS
It works in the gastrointestinal tract
It can work independently however can be influenced by the vagus (parasympathetic) and sympathetic chain