The Nervous System Flashcards
what is the nervous system?
6
a complex network of nerve cells that carry messages to and from the brain and spinal cord to different parts of the body
thus helping all parts of the body communicate with eachother
controlled by the brain
divided into….
- the central nervous system (CNS) — made up of the brain and spinal cord, receives information from the senses and controls the body’s responses
- the peripheral nervous system (PNS) — part of the nervous system that is outside the brain and spinal cord, divided into the somatic nervous system and autonomic nervous system, which is further divided into the sympathetic and parasympathetic nervous systems
each part of the nervous system has a different function but they all work together
what is the central nervous system?
3
made up of the brain and spinal cord
2 main functions; controls behaviour and regulates the body’s physiological processes
the brain receives information from the sensory receptors (e.g. eyes, ears) and sends messages to the body’s muscles and glands, this involves the spinal cord which is a collection of nerve cells running the length of the spinal column and attached to the brain
the spinal cord
5
a collection of nerve cells enclosed within the spinal column which connects nearly all parts of the body to the brain
relays information between the brain and the rest of the body, thus allowing the brain to monitor and regulate bodily processes like digestion and coordinate voluntary movements
connected to different parts of the body by pairs of spinal nerves which are connected to specific muscles and glands — for example, spinal nerves from the thoracic region of the spinal cord carry messages to and from the chest and parts of the abdomen
if the spinal cord is damaged, areas below the damaged site will be cut off from the brain and stop functioning
contains circuits of nerve cells that allow us to perform simple reflexes without direct involvement of the brain, such as pulling our hand away from something that is hot
the brain
2
responsible for coordinating sensation, intellectual and nervous activity
divided into 4 main areas; cerebrum, cerebellum, diencephalon and the brain stem
cerebrum
5
largest part of the brain
divided into 4 different lobes, each with different functions — parietal, frontal, occipital and temporal
for example, the frontal lobe is responsible for thought and speech production while the occipital lobe is responsible for the processing of visual information
split into 2 halves called cerebral hemispheres, each of which are specialised for particular behaviours
the 2 hemispheres communicate through the corpus collosum
cerebellum
3
controls motor skills and balance
coordinates muscles to allow precise movements
abnormalities in this area can results in speech and motor problems and epilepsy
diencephalon
4
includes the thalamus and hypothalamus
the thalamus is a relay station for nerve impulses coming from the senses, it directs them to appropriate parts of the brain where they can be processed
the hypothalamus regulates body temperature, hunger and thirst
it links the endocrine system and the nervous system by controlling the release of hormones from the pituitary gland
brain stem
2
regulates automatic functions which are essential for life such as breathing, swallowing and heartbeat
motor and sensory neurons travel through and the stem allows impulses to pass between the brain and spinal cord
the peripheral nervous system
3
made up of all the nerves outside the central nervous system
relays nerve impulses from the CNS to the rest of the body and from the body back to the CNS
divided into the somatic and autonomic nervous systems
somatic nervous system
5
carries information to and from the CNS
made up of 12 pairs of cranial nerves which emerge directly from the underside of the brain
also contains 31 pairs of spinal nerves from the spinal cord
these nerves have sensory neurons which relay messages to the CNS and motor neurons which relay information from the CNS to other areas of the body
involves in reflex actions without the involvement of the CNS, thus allowing reflexes to occur quickly
autonomic nervous system
4
regulates involuntary actions autonomously, these are actions that we are not consciously aware of such as our heartbeat and digestion
it is necessary for these vital bodily functions to happen automatically so we can dedicate focus to other tasks and also because these functions would not work as efficiently if we had to think about them
further divided into 2 parts; sympathetic and parasympathetic nervous systems
the sympathetic and parasympathetic nervous systems regulate the same organs but have opposite effects because each division uses different neurotransmitters
sympathetic nervous system
4
primarily involved in responses that help is deal with emergencies (such as the fight or flight response)
uses the neurotransmitter noradrenaline which has stimulating effects such as increasing heart rate and blood pressure, dilating pupils and blood vessels in muscles and releasing stored energy
neurons travel from the SNS to virtually every organ and gland to prepare the body for rapid action when the individual is under threat
slows bodily processes that are less important in emergencies such as digestion and urination
parasympathetic nervous system
4
relaxes the body when the emergency or threat has passed
uses the neurotransmitter acetylcholine which has inhibiting effects such as slowing the heart beat down and reducing blood pressure
causes digestion to begin again after the SNS has slowed it down
referred to as the rest and digest system as it is involved in energy conservation and digestion
