The nervous System

Question 1

Nervous system :

Answer 1

Allows the body to respond quickly to internal and external stimuli

Question 2

Neurons

Answer 2

Nerve cells that carry electrical signals

Question 3

Central Nervous System (CNS) consists of :

Answer 3

Brain and spinal cord

Question 4

Peripheral Nervous System (PNS) consists of :

Answer 4

Nerves

Question 5

Response to a stimulus : Reception

Answer 5

The stimulus must be detected. This is the function of receptors, neurons (nerve cells) and sense organs

Question 6

Response to a stimulus : Transmission

Answer 6

The message passes along the neurons. The neurons in the PNS carry messages from receptors to the CNS to effectors e.g, muscles or glands (receptors)

Question 7

Motor neuron (or efferent)

Answer 7

Takes a message from the CNS to a muscle or a gland

Question 8

Response to a stimulus : Integration

Answer 8

The incoming messages are sorted and processed and a response decided upon. This occurs in the CNS. Esp. in the brain

Question 9

Response to a stimulus: response

Answer 9

This is carried out by the effectors when they are stimulated by neurons

Question 10

Examples of effectors

Answer 10

Muscles or glands

Question 11

Sensory neuron (afferent)

Answer 11

Take impulses from a sense organ to the CNS. Cell bodies located outside the CNS

Question 12

Interneuron

Answer 12

Carries information between sensory and motor neurons. Only found in the CNS

Question 13

4 processes in order to make the correct response to a stimulus:

Answer 13

Reception, Transmission, Integration, Response

Question 14

Receptor

Answer 14

A cell or group of cells that detects a stimulus

Question 15

Nerve endings

Answer 15

Connect sensory neurons to receptor cells or sense organs

Question 16

Dendrites

Answer 16

Fibres (often highly branched) that carry impulses towards the cell body

Question 17

Axons

Answer 17

Carry impulses away from ce bodies

Question 18

Schwann cells

Answer 18

Produce myelin sheath

Question 19

Myelin sheath

Answer 19

A fat - rich layer that insulated the electrical impulses

Question 20

Cell body

Answer 20

Contains a nucleus and cell organelles. Contains mitochondria (provide energy for the movement of nerve impulses)

Question 21

Axon terminals

Answer 21

Branches formed by the splitting of an axon. Each of these small branches carries an impulse to a swelling called a neurotransmitter swelling

Question 22

Neurotransmitter swellings

Answer 22

Release chemicals that carry the impulse from one nerve cell to another. (Neurotransmitters) They are stored in vesicles in the swellings

Question 23

Ganglion / ganglia

Answer 23

A group of cell bodies located outside the CNS

Question 24

Resting neuron

Answer 24

A neuron that is not carrying an impulse

Question 25

Threshold

Answer 25

The minimum stimulus needed to cause an impulse to be carried in a neuron

Question 26

All or Nothing Law

Answer 26

States that if the threshold is reached an impulse is carried - but if the threshold is not reached no impulse is carried

Question 27

Refractory period

Answer 27

A short time span after a neuron has carried an impulse during which a stimulus fails to cause a response

Question 28

Synapse

Answer 28

The region where two neurons come in close contact

Question 29

Synaptic clef**t **

Answer 29

The tiny gap between the two neurons at the synapse

Question 30

Example of neurotransmitter

Answer 30

Dopamine

Question 31

Cerebellum controls :

Answer 31

Muscular coordination (and allows smooth, refined muscular action)
Balance

Question 32

Medulla Oblongata controls :

Answer 32

Involuntary actions e.g., breathing, swallowing.

Question 33

Parkinson’s disease

Answer 33

A disorder of the nervous system caused by the failure to produce dopamine ( a neurotransmitter) in a part of the brain

Question 34

Thalamus function

Answer 34

Acts as a sorting centre for the brain by sending all incoming impulses to the correct part of the brain

Question 35

Hypothalamus functions

Answer 35

• Regulates the internal environment of the body (homeostasis) by monitoring body (blood) temp. Appetite, thirst, osmoregulation and blood pressure
• Link with the pituitary gland to regulate the production of many hormones

Question 36

White matter

Answer 36

Axons only

Question 37

Grey matter

Answer 37

Cell bodies

Question 38

Reflex action

Answer 38

An automatic, involuntary, unthinking response to a stimulus

Question 39

Reflex arc

Answer 39

The pathway taken by a nerve impulse in a reflex action

Question 40

Examples of reflex actions

Answer 40

The knee jerk, control of blood pressure