The nervous system Flashcards
What is the nervous system and what are its two main functions?
The nervous system is a specialised network of cells in the body which acts as our primary internal communication system
Functions:
1) Collect, process and respond to information from our environment
2) Co-ordinate the work of our organs and cells
Central nervous system (CNS)
Consists of the spinal cord and the brain
Functions:
1) Controls behaviour
2) Regulates the body’s physiological responses
The spinal cord
Relays information between the brain and the rest of the body
Allows the brain to monitor and regulate bodily processes and co-ordinate voluntary movements
Connected to the body via pairs of spinal nerves
Allows us to perform simple reflexes without the involvement of the brain (e.g. pulling hand away from a hot stove)
The brain
Four main areas:
1) Cerebrum
2) Cerebellum
3) Diencephalon
4) Brain Stem
The cerebellum controls motor skills and balance
The brain stem regulates automatic functions (e.g. breathing)
Peripheral nervous system (PNS)
This is made up of nerves outside of the CNS
It relays impulses between CNS and the rest of the body
The two main divisions of the PNS are the somatic nervous system and the autonomic nervous system (ANS)
The somatic nervous system
Voluntary
Made up of 12 pairs of cranial nerves and 31 pairs of spinal nerves
Contains sensory neurons, which relay messages to the CNS and motor neurons, which relay messages from the CNS
Connects the nervous system and senses
Controls muscle movement
Also involved in reflex actions without the involvement of the CNS which helps them to occur very quickly
The autonomic nervous system
Involuntary
Controls important actions carried out without conscious awareness
E.g. heart beating, digestive system working
Two parts:
1) Sympathetic nervous system
2) Parasympathetic nervous system
The sympathetic nervous system
Action and stress Involved in fight or flight response Prepares body for rapid action Examples: Increased heartbeat Increased blood pressure Inhibit salivation Inhibit activity of stomach
The parasympathetic nervous system
Calm and relaxation Relaxes body after the fight or flight response once the emergency has passed Called "rest and digest system" as it is involved in energy conservation and digestion Examples: Reduced heartbeat Reduced blood pressure Stimulate saliva Stimulate activity of stomach
