The Central Nervous System (CNS) consists of the brain and the spinal cord. The CNS co-ordinates body activities by receiving impulses from sensory cells from different parts of the body.
It then sends the impulses to the appropriate effectors. The brain is enclosed within the cranium or braincase. It is covered and protected by membranes known as meninges. When meninges are infected by bacterial or fungi they cause meningitis.
The brain consists of the following parts:
Cerebrum.
- This is the largest part of the brain.
- It consists of two cerebral hemispheres.
- It is highly folded in order to increase the surface area.
- The cerebrum controls learning, intelligence, thought, imagination and reasoning.
The medulla oblongata (brain stem).
- The medulla oblongata has centres which control breathing (ventilation) rate,
- heart beat rate (cardiac frequency),
- swallowing, salivation, blood pressure
- temperature regulation, hearing, taste and touch.
The cerebellum
- Is located in front of the medulla and is a folded dorsal expansion of the hindbrain.
- It controls posture movement and balance.
The hypothalamus
- Controls functions such as body temperature and osmoregulation.
The pituitary gland
- Is an endocrine organ that secretes a number of hormones which control osmoregulation, growth, metabolism and sexual development.
Optic lobes -control the sense of sight.
Olfactory lobes -control the sense of smell.