B5 Flashcards
what does the CNS protect us from
protects organisms from harm by responding to changes in the environment
what are the CNS components
1)the brain
2)the spinal cord
what do neurones do
carry electrical impulses between receptors, the CNS and effectors
what does the CNS do
coordinates the response of effectors and coordinates responses to stimuli
what are effectors
effectors bring about actions in response to a change in the internal end external environment, like muscles contracting and
what is a synapse
synapses are gaps between neurones and can be found at each junction if a reflex arc
what are neurotransmitters
chemicals that diffuse across synapses and bind to receptors on the next neurone
they initiate electrical impulse into the next neurone
reflex action
an unconscious response that allows a person to respond to a dangerous situation rapid and automatic, by a reflex arc
components of a reflex arc
1)stimulus
2)receptor
3)sensory neurone
4)coordinator
5)motor neurone
6)effector
7)response
what happens when the nerve impulse arrives at the synapse
the electrical impulse reaches the end of the neurone before the synapse
This triggers the release of chemicals called neurotransmitters
how do electrical impulses pass on
the neurotransmitters diffuse across the synapse
The neurotransmitters bind to receptors on the dendrites of receiving neurone
The presence of the neurotransmitter causes the production of an electrical impulse
when enough receptors have been filled a threshold is reached and a electrical impulse made in receiving neurone
after, the neurotransmitter is detaches from membrane of receiving neurone and reabsorbed back into the original neurone
what is a stimulus
A stimulus can be any change in the environment to which the body needs to respond.
what is a receptors
Receptors are found all over the body.
They detect the change in the environment and initiate (start) a signalling process within the body.
The signal is picked up by a neurone (nerve cell).
what are neurones
There are three types of neurone
part of the nerve
a nerve cell
factors that effect reaction time
Caffeine and exercise are factors that could affect human reaction time
what is the medulla
This part is responsible for unconscious activities (e.g. breathing and heartbeat)
what is the cerebral cortex
This part is responsible for conscious thought (e.g. memory, language and intelligence).
what is the cerebellum
This part is responsible for the muscle coordination.
The cerebellum is important for movement, posture, balance and speech.
what are MRI scanners
MRI stands for Magnetic Resonance Imaging.
MRI scanners have allowed us to learn which areas of the brain are active during different activities, such as moving, speaking and listening.
what is electrical stimulation
Electrical stimulation has also allowed us to treat certain disorders of the brain.
Because the nervous system communicates using electrical impulses, electrical stimulation is used to help treat conditions such as Parkinson’s disease (causes tremors).
what is accommodation
lens of the eye changing shape to focus on objects
how can eye defects be treated
Both myopia and hyperopia can be treated using glasses fitted with lenses that refract light rays to allow the image to form on the retina. Contact lenses and laser eye surgery can also correct these issues.
what is myopia
short sighted
Myopia happens when rays of light focus in front of the retina.
what is hyperopia
Hyperopia happens when rays of light focus behind the retina.
long sighted