Nervous System

Question 1

What are neurons?

Answer 1

Neurons are specialised cells that allow rapid communication within the body.
* made up of cell body, containing organelles and controls the functioning of the cell

Question 2

Function of a dendrite and axon?

Answer 2

Dendrites carry the nerve impulse towards the cell body

The axon carries the nerve impulse away from the cell body.

DEND-MINE AX-BYE

Question 3

How is the nerve impulse transported if the neuron is myelinated?

Answer 3

Saltatory conduction.
* the “jumping” action of the nerve impulse from node of Ranvier to another.
* ions cannot flow into cell when there is myelin surrounding it.
*

Salt makes me jump.

Question 4

How is a nerve impulse transported via synapse?

Answer 4

• Nerve impulse reaches axon terminal activating voltage-gated calcium ion channels.
• Ca2+ ions flow into cell at presynaptic axon terminal.
• Causes synaptic vesicles to fuse with membrane, releasing neurotransmitters into the gap
• Neurotransmitters diffuse across the gap and attach to receptors on the next neuron.
• Stimulates ligand-gated protein channels to open, allowing influx of sodium ions and initiating an action potential.

VFFDL (very fat frogs deliver lemons)

Question 5

What is the somatic division in the efferent division?

Answer 5

it takes impulses to the skeletal muscles

Question 6

What is the autonomic division in the efferent division?

Answer 6

it takes impulses away from the CNS to heart and involuntary muscles and glands

Question 7

What is the purpose of the sympathetic division?

Answer 7

it activates the fight or flight response or during stress

Sympathetic is pee and flee.

Question 8

What is the purpose of the parasympathetic division?

Answer 8

It is activated when during normal bodily functions

Parasympathetic is rest and digest

Question 9

Explain the process of the sympathetic nervous system in action.

Answer 9

Fight-or-flight or alarm reaction become activated – prepares body for increased activity.
Responses include:
* ↑ rate + force of heart contractions and subsequent ↑ blood pressure
* Blood vessels involved in strenuous activity dilate (E.g. in skeletal muscles). Those not involved constrict.
* ↑ breathing rate + depth, airways in lungs dilate.
* ↑ blood glucose level (liver converts glycogen)
* ↑ secretion from sweat glands
* Adrenal medulla releases hormones adrenaline and noradrenaline to prolong/intensify response.

HBDBBSA (harry brings dishes by baker street always)