Homeostasis Flashcards
What is homeostasis
Homeostasis regulates the body systems in order to maintain a state of equilibrium
What is the points of a negative feedback loop
Stimulus— receptor—- control centre— effector
What is a stimulus
A stimulus indicates that a normal range has exceeded its ‘set point’
E.g too hot or too cold
What is a receptor?
Detects changes and forwards it to the control centre
What is the control centre
Receives information from the receptor and sends instructions to the effectors
What is the effector
Receives instructions and responds by producing a change to bring the body back to a ‘set point’
What is thermoregulation?
The process of keeping the body in a balanced state of temperature even when external temperature is different
Example of thermoregulation feedback loop
( stimulus) Body goes about 37’C
( receptor) Nerve cells in the skin and body detect change
( control centre )Temperature regulatory centre in the brain send message to sweat glands
( effector) Sweat glands in the body produce sweat to lower body temperature back to its set point
What is osmoregulation?
Maintains a stable balance of fluid and electrolytes in the body.
Stops fluid in the body from becoming too diluted or concentrated
What are osmoreceptors?
They are found in the hypothalamus and sense the concentration of fluid in the body
They control the release of ADH ( antidiuretic hormone)
What is ADH?
Antidiuretic hormone
Retains fluid in the body & reduces urination
What is osmolarity?
The concentration of solutes in the body
High osmolarity = low fluid volume in body = creating thirst= increased ADH= less urine production
Low osmolarity= increased fluid volume in body= reduced ADH= more urine production
Example of osmoregulation feedback loop
Too much salt consumed
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Water content in blood low
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Brain produces ADH
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High volume of water absorbed by kidney
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Urine output low
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Water content of blood normalWhat happens when blood glucose is too high?
Pancreas releases insulin into the body
What happens when blood glucose is too low?
Pancreas releases glucagon into the body
Homeostasis when blood glucose is low
Low blood sugar
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Detected by Pancreas
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Glucagon released by alpha cells in pancreas
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Liver breaks down glucagon & releases glucose into blood stream
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Blood sugar goes back to its set pointHomeostasis when blood sugar is too high?
Blood sugar rises above set point
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Beta cells in pancreas release insulin into blood
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Liver stores glucagon as glucose & the body cells takes up glucose
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Blood sugar levels lower back to set point of homeostasis
What is a positive feedback loop?
Where the stimulus is increased away from its set point. Requesting more rather than stopping when normal
( e.g- contractions in labour )
Example of positive feedback loop in labour
Brain stimulates pituitary glands to secrete oxytocin
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Oxytocin carried through the blood stream into uterus
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Oxytocin stimulates uterine contractions and pushes baby towards cervix
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Head pushes against cervix
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Neve impulses from the cervix transmitted to brain
