The divisions of the nervous system Flashcards
Divisions of the NS
NS- CNS/PNS
CNS- Spinal cord/ brain
PNS- Somatic NS/ Autonomic NS
Autonomic NS- Sympathetic NS/ Parasympathetic NS
The CNS
Brain and spinal cord
Recieves info from the senses and controls the body’s responses
The spinal cord
Relay info between brain and body
- allows brain to monitor and regulate bodily processes eg digestion, breathing and coordinate voluntary movements
SC is connected to diff parts of the body by pairs of spinal nerves- connect w specific muscles and glands
SC also contains circuits of nerve cells that enable us to perform simple reflexes wo direct involvement of the brain.
If SC is damaged, areas supplied by spinal nerves below the damaged area will be cut off from brain and stop functioning
The brain
Divided into 4 main areas
Cerebrum, cerebellum, diencephalon, brain stem
Cerebrum
-Largest part of brain
-Divided into 4 lobes: frontal, temporal, occipital, parietal. Each has a different primary function.
-Split down the middle into two cerebral hemispheres- specialised for particular behaviours and they communicate through the corpus callosum
Cerebellum
-Beneath the back of the cerebrum.
-Controlls a person’s motor skills and balance, coordinating the muscles to allow precise movements.
-Abnormalities= speech and motor problems and epilepsy
Deincephalon
Beneath the cerebrum and on top of the step
Two important structures: Thalamus and hypothalamus
Thalamus= relay station for nerve impulses coming from the senses, routing them to the appropriate part of the brain where they can be processed
Hypothalamus= regulation of body temp, hunger and thirst. Link between the endocrine system and the NS, controlling the release of hormones from the pituitary gland.
Brain stem
Regulating the automatic functions essential for life. eg breathing, heartbeat and swallowing.
Motor and sesnory neurons travl through the brain step, allowing impulses to pass between brain and sc
The PNS
Relay nerve impulses from the CNS to the rest of the body and back to the CNS
Somatic NS
Made up of 12 pairs of cranial nerves and 31 pairs of spinal nerves
Nerves have both sensory and motor neurons
Sensory= relay messages to the CNS
Motor= relay messages to the rest of the body from the CNS
Also involved in reflec actions wo involvement of CNS
Autonomic NS
Governs the brain’s involuntary activities eg heartbeat
Self-regulating
Divided into sympathetic and parasympathetic branch
Sympathetic NS
Responses that help us to deal w emergencies (ForF)
eg increasing heart rate, blood pressure and dilating blood vessels in the muscles.
Neurons from SNS travel to virtually every organ and gland in the body, preparing body for rapid action when under threat
Parasympathetic NS
Relaxes the body again once emergency has passed
PNS slows the heart beat down and reduces blood pressure and starts digestion again
Rest and digest
