Peripheral Nervous System

Question 1

what does the Peripharal nervous system (PNS) do?

Answer 1

co-ordinates the transmission and receiving of Impulses, to and from the central nervous system (CNS)

Question 2

What is does a Neurone do
?

Answer 2

Co-ordinates the transmission and
receiving of impulses, to and from the
central nervous system.

Question 3

What does the peripheral Nervous system consist of?

Answer 3

31 pairs of spinal nerves, 12 pairs of cranial nerves, the autonomic nervous system.

Question 4

What is a neurone

Answer 4

Highly modified cell, capable of initiating, relaying and redirecting electrical impulses.

Question 5

How does a neuron initiate and relay?

Answer 5

By converting chemical energy into electrical energy

Question 6

What are the functions of a neurone

Answer 6

Controlling muscle activity, regulating glands, supporting and protecting the nervous system.

Question 7

What is an Dendrite?

Answer 7

an extension of the cell body that carries impulses towards the cell body.

Question 8

what is an axon?

Answer 8

an extension of the cell body that carries impulses away from the cell body.

Question 9

what is the node of Ranvier?

Answer 9

narrow , non-insulated part of the neurone that boosts the strength of the impulses as it passes along.

Question 10

What do Schwann cells do?

Answer 10

produce and secrete neurilemma, which forms the outer layer of the neuron myelin sheath.

Question 11

What do Boutons do?

Answer 11

They are small end bulbs from which chemical transmitters are released and found in the Axon terminal.

Question 12

how does a neurone transmit an impulse?

Answer 12

signal transmitted –> Myelin sheath covering the axon allows ions to leak through. potassium and sodium ions change places creating an electrical signal that travels along the membrane. when impulses reach the synapse the vesicles inside discharge chemical transmitters which transmit the impulse next to the neuron.

Question 13

what does acetycholine do?

Answer 13

binds to sodium and potassium which depolarizes the membrane and a nerve impulse is generated, causing muscle fibres to contract.

Question 14

What happens to chemical transmitters if the body goes into alkalosis?

Answer 14

PH of 7.8 can cause cerebral convulsions.

Question 15

What happens if the body goes into acidosis?

Answer 15

PH below 6.5 will depress neural activity causing a coma.

Question 16

What are most of the nerves involved in the PNS composed of?

Answer 16

Sensory nerves fibres that are afferent (bearing or conducting inwards) and motor nerve fibres that are efferent (conducting outwards from a part or organ)

Question 17

what are the efferent nerves divided into?

Answer 17

Somatic (Voluntary)
Autonomic (Involuntary)

Question 18

What are afferent neurones ?

Answer 18

they are sensory.
- usually unipolar
-they convey information from receptors in the periphery
- skin and sense organs to the CNS or the connector neurons of the reflex arc

Question 19

how many spinal nerves are there?

Answer 19

31 pairs of spinal nerves.

-8 cervical
-12 thoracic
-5 lumbar
-5 sacral
-1 coccygeal

Question 20

What is a reflex?

Answer 20

a motor response with no intervention from the brain.

Reflex actions are specific responses to a
sensory stimulus with no conscious control

Question 21

What 5 things are required for a reflex action?

Answer 21

A receptor
A sensory neurone
An associated neurone
A motor neurone
An effector

Question 22

what are the types of reflexes?

Answer 22

Spinal Reflex:
Sensory impulse for quick action

Cortical Reflex:
Overrides spinal reflex under conscious control

Coordinating Reflex:
Modifies movement and coordinates

Autonomic Reflex:
Immediate reaction to situations
Over rules conscious decisions

Question 23

how does the autonomic nervous system work?

Answer 23

The effects of autonomic control are mainly
stimulation or depression of glandular secretions
and contraction of cardiac and smooth muscle
tissue

Question 24

What are examples of what the autonomic nervous system controls?

Answer 24

Rate and force of the heartbeat
Secretions of glands of the alimentary tract
Vasoconstriction or dilation
Change in the size of the pupils of the eyes

Question 25

what is sympathetic?

Answer 25

Fight or Flight

Adrenaline
&
Noradrenaline

Question 26

what is parasympathetic?

Answer 26

Sleep, rest and
digestion

Acetylcholine