The Nervous System and The Endocrine System
The nervous system
The nervous system is a specialised network of cells in the human body and is our primary
internal
communication system. It has two main functions:
• To collect, process and respond to information
in the environment.
• To co-ordinate the working of different organs
and cells in the body.
It is divided into two sub-systems
1. Central nervous system CNS)
2. Peripheral nervous system PNS).
The central nervous system
The CNS is made up of the brain and the spinal cord.
• The brain is the centre of all conscious awareness. The brain's outer layer, the cerebral
cortex, is highly developed in humans and is what distinguishes our higher mental functions
from those of animals. Only a few living creatures - sponges, sea squirts, jellyfish-and some
Manchester United fans – do not have a brain. The brain is divided into two hemispheres
• The spinal cord is an extension of the brain. It is responsible for reflex actions such as
pulling your hand away from a hot plate. It passes messages to and from the brain and
connects nerves to the PNS.
The peripheral nervous system
The PNS transmits messages, via millions of neurons (nerve cells), to and from the
central nervous system. The peripheral nervous system is further sub-divided into the
• Autonomic nervous system (ANS) governs vital functions in the body such as
breathing, heart rate, digestion, sexual arousal and stress responses.
• Somatic nervous system (SNS) controls muscle movement and receives
information from sensory receptors.
The nervous system
The nervous system is a specialised network of cells in the human body and is our primary
internal
communication system. It has two main functions:
• To collect, process and respond to information
in the environment.
• To co-ordinate the working of different organs
and cells in the body.
It is divided into two sub-systems
1. Central nervous system CNS)
2. Peripheral nervous system PNS).
The central nervous system
The CNS is made up of the brain and the spinal cord.
• The brain is the centre of all conscious awareness. The brain's outer layer, the cerebral
cortex, is highly developed in humans and is what distinguishes our higher mental functions
from those of animals. Only a few living creatures - sponges, sea squirts, jellyfish-and some
Manchester United fans – do not have a brain. The brain is divided into two hemispheres
• The spinal cord is an extension of the brain. It is responsible for reflex actions such as
pulling your hand away from a hot plate. It passes messages to and from the brain and
connects nerves to the PNS.
The peripheral nervous system
The PNS transmits messages, via millions of neurons (nerve cells), to and from the
central nervous system. The peripheral nervous system is further sub-divided into the
• Autonomic nervous system (ANS) governs vital functions in the body such as
breathing, heart rate, digestion, sexual arousal and stress responses.
• Somatic nervous system (SNS) controls muscle movement and receives
information from sensory receptors.
