Nervous system is
a specialised
network of cells
and acts as the
primary internal
communication
system
Two main functions
Collect, process, and respond to environmental stimuli
Co-ordinate the working of different cells and organs in the
body
Two main sub systems
Central nervous system (CNS)
The brain is the centre of conscious awareness
Outer layer, cerebral cortex, is highly developed which distinguishes our higher mental functions from animals
Split into two hemispheres
Spinal cord is an extension
of the brain
Responsible for reflex actions
Passes messages from PNS to brain and back
Peripheral nervous system (PNS)
Passes messages via millions of
neurons to the CNS
Two sub systems
Autonomic nervous system (ANS)
Governs vital responses in the
body such as breathing and
heart rate
Somatic nervous system (SNS)
Controls voluntary muscle
movement and receives
information from sensory
receptors
Endocrine system
Made up of and
controls glands that
secrete hormones into
the bloodstream to be
carried towards target
organs
Hormones affect cells
leading to many
diverse and powerful
effects
When a stressor is perceived , the
hypothalamus triggers the change in the ANS
from parasympathetic (rest) to sympathetic
(alert). Adrenlaine id released from the
adrenal medulla which triggers changes in the
body (such as faster heart rate and slower
metabolism) which is necessary for the fight
or flight response. When the stressor is gone
the ANS returns to its parasympathetic state
which is antagonistic to the sympathetic state