Introduction To The Nervous System

Question 1

Parts of a neuron

Answer 1

Cell body-contains fairly large nucleus
Dendrites- branding projections that receive info from other nerves
Axon- long nerve fibres. Conduct the action potential. Cluster of axons=nerve
Axon terminal- the synapse where electrical become chemical (neurotransmitters to other cells)
Myelin sheath- insulting axon cover increases speed of depolarisation
Node of Ranvier: gaps between myelin sheath

Question 2

Integration, what is it?

Answer 2

When the nerve combines all the inhibitory and excitatory impulses it’s getting to produce or not produce an action potential.

Question 3

Glial cells

Answer 3

Other cells in the nervous system
Protect and support neurones (4)
Astrocytes
Oligodendrocytes
Microganglia 
Ependymal cells

Question 4

Astrocytes

Answer 4

Help regulate the iconic composition of the extracellular fluid. Remember the brain needs an extremely stable environment in order to function

Question 5

Ependymal

Answer 5

Production and maintenance of cerebro-spinal fluids

Question 6

Microglia

Answer 6

Macrophages of CNS (normal macrophages aren’t allowed into CNS)

Question 7

Oligodendrocytes

Answer 7

Myelin sheath of the CNS

In periphery is called Schwann cell

Question 8

Creating the electrical signal- membrane potential

Answer 8

Membrane potential = difference in charge between outside and inside the membrane
INside = negative

More Na outside, not freely permeable. K freely permeable

Sodium potassium pump, Na out K in

At rest K diffuses out to keep difference low = resting membrane potential.

Question 9

Excitable cells

Answer 9

These are cells with a resting membrane potential
They can depolarise to creat an action potential
Nerve and muscle cells

Question 10

Depolarisation

Answer 10

Sodium channels open
Sodium rapidly diffuses across membrane
Inside becomes more negative

Question 11

Repolarisation

Answer 11

Sodium channels close again
Potassium opens
S-P pump tidies

Question 12

Role of myelin sheath

Answer 12

The insulation means it only has to cross over at nodes of ranvier not all the way down

Question 13

Neurotransmitters

Answer 13

Drugs commonly target here
Released when hit by action potential
Received by next cell
Message terminated when enzymes Brea them down and bring them back to the synaptic bulb.

Question 14

Divisions of the nervous system

Answer 14

Central Peripheral
(Brain and spinal cord). (Cranial nerves 12 and spinal nerves 31)
Somatic. Autonomic
(Voluntary). Sympathetic. Parasympathetic
(Fight flight). (Rest repose)
Sensory. Motor

Question 15

SAME

Answer 15

Sensory afferent

Muscle efferent

Question 16

Control loops in nervous system

Answer 16

Stimulus in internal or external environment
Sensory detect change and relay
CNS processes and effects response
Muscles carry out response

Question 17

The simplest reflex > the stretch reflex

Answer 17

Processed on a spinal level
Involves two neurones
Sensory organs detect i.e. Muscle stretching
Action potential travels to afferent spinal section
Sensory neurone synapse with motor neurone in grey matter in spine
Motor neurone action potential cause muscle to contract

Question 18

A more complex reflex

Answer 18

Pain- 3
Stimulate bicep
Inhibit tricep
Signal pain