B12 Homeostasis in action Flashcards
paper 2
What is homeostasis?
maintenance of a constant internal environment
Give three internal conditions controlled in homeostasis.
body temperature, blood glucose concentration, water levels
GIve three things all control systems include.
receptors, coordination centres and effectors
Where is body temperature monitored and controlled?
thermoregulatory centre in the brain.
What happens if body temperature is too high?
blood vessels dilate (vasodilation) and sweat is produced
What happens if body temperature is too low?
blood vessels constrict (vasoconstriction), sweating stops and shivering takes place
What is the function of the kidneys?
filter and reabsorb useful substances from the blood and produce urine to excrete excess water, ions and urea.
How are excess amino acids excreted from the body?
deaminated to form ammonia in the liver, ammonia is converted to urea and excreted
Which hormone controls the water level in the body?
ADH
How is kidney failure treated?
organ transplant or dialysis
In kidney dialysis, what fluid is temporarily removed from the patient’s body?
Blood
In kidney dialysis, name one substance that diffuses from the patients blood into the dialysis fluid?
Urea or waste products
Define diffusion.
The movement of particles from an area of higher concentration to an area of lower concentration
What are proteins broken down into?
amino acids
Amino acids are deaminated to form ammonia i what organ of the body?
The liver
Why does ammonia need to be excreted safely?
Ammonia is toxic
State three things controlled by negative feedback in the body.
Blood glucose
Water
Thyroxine
Where is the hormone adrenaline produced?
Adrenal glands
What is the function of adrenaline?
Prepares the body for fight or flight, increases the heart rate
Where is the hormone thyroxine produced?
Thyroid gland
What is the function of thyroxine?
Regulates how quickly the body produces energy, makes proteins.
