The Central Nervous System

Question 1

The Brain

Answer 1

The brain is the upper, enlarged part of the spinal cord
It is protected by the Cranium in which it lies and by a system of three membranes called the Meninges
within the brain are hollow cavities called Ventricles filled with Cerebrospinal Fluid
The Brain gives rise to twelve pairs of nerves referred to as Cranial Nerves

Question 2

The Functions of the Brain

Answer 2

It receives and interprets all sensations viz. sight, hearing, smell, taste and touch
It controls all the higher thought processes such as memory, judgement, reasoning, etc
It controls all voluntary actions and is responsible for all the involuntary actions as well
It co-ordinates voluntary movements e.g. walking and running
It maintains muscle tone, balance and equilibrium

Question 3

The Cerebrum

Answer 3

The Cerebrum is the largest part of the brain
It is made up of grey matter on the outside and white matter on the inside
It is divided into left and right hemispheres: left hemisphere controls the activities of the right side of the body while the right hemisphere controls the activities of the left side of the body
The two hemispheres are connected together by bundle of nerve fibres, the largest of which is the Corpus Callosum
Below the Corpus Callosum is the Thalamus
Below the Thalamus is the Hypothalamus

Question 4

The Functions of the Cerebrum

Answer 4

It controls all voluntary actions
It receives and interprets all sensations viz. sight, hearing, smell, taste and touch
It controls all the higher thought processes such as memory, judgement and reasoning

Question 5

What is the Hypothalamus responsible for

Answer 5

The Hypothalamus is responsible for the control of:
Body Temperature
Blood Pressure
Sleep
Appetite
Thirst
Emotions

Question 6

What is the Cerebellum

Answer 6

The Cerebellum is situated behind the Pons Varolii and the Medulla Oblongata
It is made of grey matter on the outside and the white matter on the inside

Question 7

The Functions of the Cerebellum

Answer 7

Co-Ordination of voluntary movements e.g. walking and running
maintaining muscle tone, balance and equilibrium

Question 8

The Brain Stem

Answer 8

The Brain Stem is made up of the mid-brain, the Pons Varolii and the Medulla Oblongata

Question 9

The Medulla Oblongata

Answer 9

The Medulla Oblongata continues as the Spinal Cord
It contains Cerebrospinal Fluid which continues in the central canal of the Spinal Cord
It has white matter on the outside and grey matter on the inside

Question 10

The Functions of the Medulla Oblongata

Answer 10

It contains the reflex centres responsible for breathing, regulation of the heart beat, dilation and constriction of blood vessels, salivation and swallowing i.e. it is responsible for all involuntary actions
it conducts impulses from the Spinal Cord to the higher parts of the brain, and vice versa
Impulses cross-over from one side to the other as they pass through the medulla so that nerves from the left side of the brain control the right side of the body and vice versa