The divisions of the nervous system: central and peripheral (somatic and autonomic) Flashcards
what is the nervous system
The nervous system is a highly organised collection of neurons that conveys information around the organism and between the organism and its environment.
what is the central nervous system
The central nervous system (CNS) is the body’s master control unit. Its role is the processing of incoming information and the preparation of responses.
what is the spinal cord
Most of the information travelling to and from the brain from the peripheral nervous system does so via the spinal cord, which is also capable of basic information processing in its own right.
what is the brain
The brain is the control centre for the nervous system and many of the body’s other systems. It is capable of very complex information processing
what is the peripheral nervous system
The role of the peripheral nervous system (PNS) is to transmit information from the environment to the central nervous system, and from the CNS to other parts of the body.
what is the autonomic nervous system
The autonomic nervous system (ANS) regulates involuntary (without conscious direction) bodily processes (internal organs and glands), including heart rate, respiration, digestion and pupil contraction and is involved in homeostatic functions. ANS control centres are in the brain stem and consists of purely motor pathways.
what is the somatic nervous system
The somatic nervous system (SNS) consists of sensory nerves, which carry information from the environment to the CNS, and motor nerves, which carry instructions to and from the CNS (motor cortex) to the skeletal muscles – involved in movement (voluntary movements).
what is the sympathetic branch of the ANS
The sympathetic branch (SANS) of the ANS. It consists of a series of connections from the spinal cord to the major internal organs. It becomes more active when we are doing anything which requires the expenditure of energy. It is also involved in the ‘freeze/fight/flight response’ that occurs when an organism is threatened.
what is the parasympathetic branch of the ANS
The parasympathetic branch (PANS) of the ANS consists of a series of connections between the brain and the internal organs. It is active most of the time, controlling homeostatic functions and ensuring that we conserve energy – it essentially maintains or decreases bodily activities. It becomes less active when the SANS becomes more active
The CNS has two main functions:
The control of behaviour
The regulation of the body’s physiological processes
Comprises the spinal cord and the brain.
The Spinal Cord
Main function: relays information between the brain and the rest of the body (peripheral nervous system).
Allows the brain to monitor and regulate bodily processes such as digestion and breathing, as well as coordinate voluntary movements (via the somatic nervous system).
If it is damaged, areas of the body that are supplied by spinal nerves below the damaged point will be cut off from the brain and stop functioning.
Cerebrum
This is the largest part of the brain and makes up about 85% of the total mass of the brain.
The cerebrum is split into two halves = hemispheres
Each hemisphere is further divided into four different parts, known as lobes
The outer surface of the cerebrum is called the cerebral cortex, which is responsible for the ‘higher-order’ functions, such as thought and language.
what are the frontal lobes involved in
Frontal lobes = involved with speech, thought and learning.
what are the parietal lobes involved in
Parietal lobes = sensory information e.g. touch, temperature and pain.
what are the occipital lobes involved in
Occipital lobes = process visual information.
what are the temporal lobes involved in
Temporal lobes = involves with hearing and memory
what is the Cerebellum
– it is involved in controlling motor skills and balance, coordinating the muscles to allow precise movements.
what is the Diencephalon
Diencephalon – Consists of the thalamus, hypothalamus, epithalamus (including the pineal gland) and subthalamus.
what is the thalamus
The thalamus receives nerve impulses from the senses, sending them to the appropriate part of the brain to be processed.
what is the hypothalamus
The hypothalamus regulates body temperature, hunger and thirst. It also acts as the link between the endocrine system and the nervous system, controlling the release of hormones from the pituitary gland.
what is the pineal gland
The pineal gland (found within the epithalamus) secretes melatonin (involved in regulating the sleep-wake cycle).
what is the Brain stem
Brain stem – Regulates automatic functions e.g. breathing , heartbeat, swallowing. Motor and sensory neurons travel through the brainstem, allowing impulses to pass between the brain and spinal cord.
The Peripheral Nervous System
All the nerves outside of the CNS make up the peripheral nervous system.
The peripheral nervous system’s function is to relay nerve impulses from the Central Nervous System to the rest of the body and back again.
It has two main divisions:
the somatic nervous system (SNS)
the autonomic nervous system (ANS)
The Somatic Nervous System
Made up of pairs of cranial nerves (that emerge from the brain) and spinalnerves (that emerge directly from the spine).
It is involved in the transmission of information to and from the CNS.
It has sensory and motor pathways.
It consists of sensory nerves that carry information from the environment towards the central nervous system e.g. visual information from the eyes.
It also consists of motor nerves, which carry instructions from the central nervous system (the motor cortex) towards skeletal muscles.
It therefore controls skeletal muscle and is involved in voluntary (conscious) actions.
It is also involved in reflex actions (a nearly instantaneous movement in response to a stimulus), such as touching a hot object, sneezing, blinking, yawning.
The Autonomic Nervous System
Regulates involuntary actions/bodily processes (without conscious awareness), for example: heart rate, breathing, digestion.
Its control centres are in the brain stem and consists of purely motor pathways.
It controls internal organs and glands (e.g. adrenal gland) of the body.
It has two branches: sympathetic and parasympathetic, which regulate the same organs, but have the opposite effects on them.
The sympathetic branch increases bodily activities e.g. the fight or flight response – increased heart rate.
The parasympathetic branch maintains or decreases bodily activities e.g. returns heart rate to normal after activation of the fight or flight response (‘rest and digest’).
The Somatic and Autonomic Nervous System: Key Differences
Somatic Nervous System:
1)Under conscious control – involved in voluntary actions
2)Controls skeletal muscle, movement etc.
3)It consists of sensory and motor pathways
4)It carries commands from the motor cortex
Autonomic Nervous System:
1)Regulates involuntary actions/bodily processes
2)Controls internal organs and glands of the body
3)It consists of purely motor pathways
4)Its control centres are in the brain stem
