Homeostasis - negative and positive feedback Flashcards
What does negative feedback do?
Works to maintain a steady state (homeostasis). Whatever the initial change, negative feedback would cause the opposite response.
What is the basic order of how negative feedback works?
Stimulus, sensor, control, response (effector). The effector changes the stimuli.
How does the thyroid gland produce thyroxine?
Uses iodine from your diet.
What does thyroxine control?
Basal metabolic rate.
Amount of oxygen your tissues use.
How the brain of a growing child develops.
Growth and development.
What is metabolism?
How quickly substances are broken down and built up, how fast chemical reactions take place.
What happens if level of thyroxine falls?
Sensors in pituitary gland detect change.
Pituitary gland releases increased amounts of TSH.
TSH acts on thyroid gland, stimulates thyroid to produce more thyroxine.
What happens if level of thyroxine is too high?
Sensors in pituitary gland detect change.
Pituitary gland decreases amount of TSH released.
Little/none TSH acting on thyroid gland so thyroxine levels fall.
What does positive feedback do?
It amplifies your body’s response to a stimulus until a negative feedback response takes over.
What secretes the hormone adrenaline?
Adrenal glands (above kidneys).
What does adrenaline cause?
Increased heart rate and breathing rate.
Glycogen converted to glucose for respiration.
Pupils dilate to let in more light.
Mental awareness increases.
Blood diverted from digestive system to muscles and limbs.