CNS

Question 1

What are the main function of the CNS

Answer 1

Sensation- changes in body and environment
Integration- makes sense of changes
Response- initiates a response

Question 2

What are the 2 principle types of cell in CNS

Answer 2

Neurones- functional unit ( help transmit nerve impulse)
Neuroglia - support and protect neurones ( Maintain homeostasis )

Question 3

3 characteristics of a neurone

Answer 3

Cell body- core section
Axon - long tail like structure
Dendrite- fibrous roots that branch out of cell body and communicate with adjacent neurones

Question 4

What is the action potential of the nerve cell

Answer 4

Occurs when neurone sends information down axon away from cell body
Nerve fires when depolarised ( inside of cell is positive)
And stops firing when polarised ( inside of cell is negative)

Question 5

Main characteristics of action potential of the nerve cells

Answer 5

Depolarisation is Na dependent

Na goes in and K goes out

Impulse needs to reach action potential to carry on- if not reached message wont continue to be transmitted

Resting membrane potential is -70mV

Question 6

How do the drugs modulate the nerve firing

Answer 6

deter cell depolarisation by blocking Na and Ca channels
Render it negatively charged by leaving K Chanel’s open

Question 7

What is Saltatory conduction

Answer 7

Way an electrical impulse skips from node to node down the length of the axon
Only occurs in myelinated nerves
Dramatically increases conduction velocity
Impulse jumps between nodes of ranvier

Question 8

Speed and nerve impulse are dependent on size and type of nerve ..explain

Answer 8

Large - myelinated A fibres = fast motor ( sharp, stabbing acute pain)
Small unmyelinated - C fibres = slow (achy or throbbing pain, itch, cough)

Question 9

What is a synapse

Answer 9

Junction between 2 nerve cells - impulses pass by diffusion or neurotransmitter

Question 10

What is antidromic conduction

Answer 10

Conduction of nerve cells in a reverse direction- back tracks

Question 11

What are neurotransmitters

Answer 11

Chems released into synaptic cleft
100 or more varieties in brain
Bind to post synaptic receptors
Neurotransmitter dysfunction implicated in mental health

Question 12

4 groups of neurotransmitters?

Answer 12

Biogenic- ACH, monoamines, noradrenaline

Amino acids- GABA, glutamate, glycine

Peptides - endorphins, enkephalins

Other- nitric oxide, adenasine

Question 13

Noradrenaline is produced in?

Answer 13

CNS

Question 14

Adrenaline is produced in?

Answer 14

Endocrine system

Question 15

How do neurotransmitter work

Answer 15

Stored in the axon terminals on neurone in small asks called synaptic vesicles
Presynaptic nerve excited by electrical signal (action potential), releases neurotransmitter into synaptic cleft

Pre synaptic nerve excited by electrical signal (action potential) releases neurotransmitters into synaptic cleft
When in the synaptic cleft the neurotransmitter interacts with the post synaptic receptors and cause a reaction to occur in the post synaptic neurone. This increases or decreases the likeliness the post synaptic neurone will become activated and fire an action potential

Question 16

What is saltatory conduction

Answer 16

describes the way an electrical impulse skips from node to node down the full length of an axon

Signal jumps from one node of ranvier to another down a myelinated neuron

Question 17

What are the main characteristics of the parasympathetic nervous system? (5)

Answer 17

Concerned with conservation and restoration of energy

Otherwise known as ‘cranio-sacral’ outflow
Long pre ganglionic fibre, short post ganglionic fibre

Neuro transmitter Acetylchlorine (ACh) acts on nicotinic and muscarinic receptors

Responsible for cholinergic transmission

(A substance (or ligand) is cholinergic if it is capable of producing, altering or releasing ACh)

Question 18

What are the main characteristics of the sympathetic nervous system? (5)

Answer 18

Otherwise known as ‘thoracolumbar’ outflow

fight or flight

Short pre ganglionic fibre, long post ganglionic fibre

Neurotransmitter ACh pre ganglionic and noradrenaline post ganglionic

a and b receptors

Question 19

Nicotinic receptors are

Answer 19

Nicotinic (nAChR) - coupled to cation channels. Membrane depolarisation and fast excitatory transmission receptors

Question 20

Muscarinic receptors are

Answer 20

Muscarinic (mAChR) - G protein coupled receptors with 5 sub types

(M2 = cardiac and M3 = smooth muscle)

Question 21

What is axoplasmic flow?

Answer 21

Axoplasmic flow is the movement of neurotransmitters from the neurone cell body to where it needs to be ? Axon terminal