nervous system Flashcards
nervous system
The human nervous system is a complex network of nerve cells that carry messages to and from the brain and the spinal cord to different parts of the body, so it helps all parts of the body to communicate with each other.
The brain controls the nervous system and has many billions of cross-connections.
The brain oversees the workings of the body, while its higher functions provide us with consciousness and make us who we are.
Divided into the central nervous system (CNS) and the peripheral nervous system, with are each further divided into different components, each with a different function but all working together.
central nervous system
The CNS comprises the brain and the spinal cord.
Controls behaviour and regulates the body’s physiological processes.
In order to do this, the brain must be able to receive information from the sensory receptors. (eyes, ears etc)
Sends messages to the muscles and glands in the body,
spinal cord
Relays information between the brain and the rest of the body.
Allows the brain to monitor and regulate bodily processes, such as digestion and breathing and to coordinate voluntary movements.
brain
Centre of all conscious awareness.
Each part of the brain is involved with a different part of functioning, e.g. the occipital lobe is involved in the visual processing of images.
The brain stem regulates the automatic functions that are essential for life such as heartbeat, breathing and swallowing.
Motor and sensory neurons travel through the brain stem, allowing impulses to pass between the brain and the spinal cord.
peripheral nervous system
All the nerves outside the CNS make up the peripheral nervous system.
Relays nerve impulses from the CNS to the rest of the body and from the body back to the CNS.
There are 2 main divisions - the somatic nervous system and the autonomic nervous system.
somatic nervous system
Governs muscle movement and transmits + receives messages from the senses via different types of neurons.
Sensory neurons send messages to the CNS
Motor neurons pass information from the CNS to direct muscles.
autonomic nervous system
Regulates involuntary actions such as heartbeat and digesting food.
A necessary system as the body would not work as efficiently if these actions required thinking.
Split into the sympathetic and parasympatheic nervous system.
The sympathetic nervous system is responsible for the fight or flight response and mobilises the body for action.
The parasympathetic nervous system is responsible for calming the body and conserves energy.
