Homeostasis Flashcards
What is homeostasis?
Your body’s ability to regulate and maintain a stable
condition inside your body, regardless of changes to the
external environment.
what are some conditions in the body that need to be kept constant?
body temperature at 37°C
the amount of water inside our body
blood sugar levels
Stimulus-response model
Stimulus
Receptor
Control Centre
Effector
Response
Negative feedback loop
Negative feedback loop
Temperature
Body temperature is too low
Temperature receptors detect low temperature and send message to brain.
Hypothalamus sends message to muscles and blood vessels.
Muscles start to shiver and blood vessels constrict to reduce heat loss.
Body temperature returns to normal.
Message sent to brain to get effectors to stop.
Negative feedback loop
Glucose too high
Blood glucose is too high
Receptors in blood detect high levels of glucose and send message to brain.
Hypothalamus sends message to pancreas.
Pancreas releases more insulin into the blood to store glucose in liver as glycogen
Body glucose levels return to normal.
Message sent to brain to get effector (pancreas) to stop releasing insulin.
How blood glucose levels are regulated?
Pancreas produces insulin. Insulin then absorbs the glucose.
What is a positive feeback loop?
A positive feedback loop occurs in nature when the product of a reaction leads to an increase in that reaction.
include blood clotting and childbirth.
Negative feedback loop
when the response counteracts the initial stimulus
Negative feedback loop
Too little Glucose
Blood glucose is too low
Receptors in blood detect low levels of glucose and send message to brain.
The hypothalamus sends message to liver
liver releases more glycogen into the blood to transfer back into glucose.
Body glucose levels return to normal.
Message sent to brain to get effector (pancreas) to stop releasing insulin
