homeostasis and response Flashcards
what is homeostasis
is all about the regulation of the conditions inside your body to maintain a stable internal environment in response to changes in both internal and external conditions
what is negative feedback
when the level of something gets too high or too low your body uses negative feedback to bring it back to normal
the process of negative feedback
1) receptor detects a stimulus
2) the coordination centre recives and processes the information
3) effector produces a response witch counteracts the change
what the effectors do after the change
will carry on the response for as long as stimulated by coordination centre, the receptor detects this and negative feedback is back on
central nerous system
i vertebrates this consits of the brain and spinal cord only.
in mammals it is connecte3d to the body by sensory neurons and motor neurons
is a coordination centre
sensory neurons
the neurons that carry information as electrical impulses from the receptors to the cns
motor neuron
the neurons that carry electrical impulses from the cns to the effector
receptors
are the cells that detect stimuli
effectors
respond to nervous impulses and bring about a change
mussels and glands are effectors
reflexes
are rapid, automatic responses to certain stimuli that dont involve the conscouios part of the brain
how the reflex arc works
1) when a stimulus is detected be the receptors impulses are sent along sensory neurone to a relay neurone
2) when the impulse reaches the synapse they trigger chemicals to be re;easesd these chemicals cause impulses to be sent along the relay neurone
3) the impulses travel along the motor neurone to the effector
4) the muscle then contracts and moves your hand away from the bee
the brain
made up of billions of interconnected neurons and is in charge of our complex behaviors
optic nerve
carries impulses from the receptors on the retina to the brain
what is the thermoregulatory centre
contains receptors that are sensitive to the temperature of the blood flowing through the blood
what happens when there is a change in temperature
1)temperature receptors detect that the body is too cold or hot
2)thermoregulatory centre acts as a coordination centre
it receives the information and triggers the effectors
3)effectors produce a response
what happens when youre hot
sweat is produced
blood vessels dilate so more blood goes to your skin this is called vasodilation
what happens when youre cold
hairs stand up
blood vessels supplying the skin constrict this is called vasoconstriction
how do neurons go between synapses
1) electrical impulse travels along an axon
2) triggers chemical messengers called neurotransmitters
3) chemicals diffuse across synapses and bind with the receptor molecules on the mebrane of the next neuron
4) the second neuron then transmits an eectrical impulse
What is vascodilation
Blood vessels dilating
What is vasoconstriction
Blood vessels constrict
how the CNS coordinates the response in negative feedback
bird example
1) bird spots cat and the receptors in the eye is simulated
2) sensory neurons carry’s the information to the CNS and it decides what to do
3) CNS sends information to the effectors via the motor neurons
4) muscles contract and bird fly’s away
what are synapses
connection between two neurons
what does the cerebellum do
responsible for muscle coordination
what does the medulla do
controls unconscious activities
