The nervous system Flashcards
The nervous system
The nervous system is a specialised network of cells in the human body and is our primary internal communication system.
Consists of the central nervous system and the peripheral nervous system.
What are it’s 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.
Central nervous system (CNS)
- made up of the brain and the spinal cord.
- origin of all complex commands and decisions.
Brain:
- centre of all conscious awareness.
- divided into two hemispheres.
- outer layer (cerebral cortex) highly developed- distinguishes mental functions from animals.
Spinal cord:
- extension of brain.
- responsible for reflex actions.
- passes messages to and from brain- connects nerves to PNS.
Peripheral nervous system (PNS)
- sends information to the CNS from outside world.
- transmits messages from the CNS to muscles and glands in the body.
- sends info. via millions of neurons.
- further subdivided into the autonomic nervous system and somatic nervous system
Autonomic nervous system (ANS)
- sub-division of PNS
- system operates involuntarily.
- transmits info. to and from internal bodily organs.
- governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses.
- Two main divisions- sympathetic and parasympathetic nervous system.
Somatic nervous system (SNS)
- sub division of the PNS
- transmits info. from receptor cells in the sense organs to the CNS.
- receives info. from CNS that directs muscles to act.
- controls muscle movement and receives info. from sensory receptors.
Parasympathetic and sympathetic nervous systems
PS -> a resting state, relaxed and comfortable ‘rest and digest’
Heart rate = consistent and steady.
Pupils = constricted.
S -> when the body is physiologically aroused ‘fight or flight’
Heart rate = intensity increased.
Pupils = dilated.
FINISH BODILY RESPONSES!
