The Nervous System Flashcards
What are the two main functions of the nervous system?
- To collect, process and respond to information in the environment
- To co-ordinate the working of different organs and cells in the body.
What can the nervous system be divided into?
The Central Nervous System and the Peripheral Nervous System.
What is the Central Nervous System made up of?
The brain and the spinal cord. The brain is the centre of conscious awareness - the cerebral cortex is a 3mm thick layer over the whole brain that is responsible for consciousness. The spinal cord is an extension of the brain. It passes messages to and from the brain and connects nerves to the PNS. It is also responsible for reflex actions.
What is the function of the Peripheral Nervous SYstem?
The PNS transmits messages via millions of neutrons to and from the CNS.
What is the PNS divided into
The Autonomic Nervous System and the Somatic Nervous System.
What is the function of the ANS?
The ANS governs vital functions such as breathing, heart rate, digestion, sexual arousal and stress responses.
What is the function of the SNS?
The SNS governs muscle movement and receives information from sensory receptors.
What happens when a stressor is perceived?
The hypothalamus activates the pituitary gland, triggering activity in the sympathetic branch of the ANS. The ANS changes from its normal resting state (parasympathetic state) to the physiologically aroused sympathetic state.
What happens once the threat has passed?
The parasympathetic nervous system returns the body to its resting state. It acts as a brake and reduces the activities of the body that were increased by the actions of the sympathetic branch. This is the ‘rest and digest’ response.
