B3.3 Homeostasis Flashcards
What waste products need to be removed form the body?
Carbon dioxide and urea
What is carbon dioxide produced by?
Respiration
How is carbon dioxide removed?
Via the lungs when we breathe out
What is urea produced by?
The liver in the breakdown of amino acids
How is urea removed?
By the kidneys in the urine, which is temporarily stored in the bladder
What may happen if the water or ion content of the body is wrong?
Too much water may move into or out of the cells and damage them
How do water and ions enter the body?
When we eat and drink
How does a healthy kidney produce urine?
It filters the blood, then it reabsorbs all the useful subsatances such as: sugar, dissolved ions, and as much water that the body needs. Then it releases urea, excess ions and water as urine
How may people suffering kidney failure be treated?
Either by using a kidney dialysis machine or by having a healthy kidney transplanted
What does treatment by dialysis do?
It restores the concentrations of dissolved substances in the blood to normal levels and has to be carried out at regular intervals
In a dialysis machine, what does a person’s blood flow through?
A partially permeable membrane
What concentration does the dialysis fluid contain?
The same concentration of useful substances as the blood. This ensures that glucose and useful mineral ions are not lost
In dialysis, what does urea pass in to?
The dialysis fluid from the blood
What happens in a kidney transplant?
A diseased kidney is replaced with a healthy one from a donor
What may happen to the transplanted kidney?
It may be rejected by the immune system unless immunosuppressant drugs are taken to prevent this from happening
What are antigens?
Proteins on the surface of cells
What may the recipient of the transplant’s antibodies do to the antigens on the donor organ?
Attack them as they do not recognise them as part of the recipient’s body
How do you prevent the rejection of the transplanted kidney?
A donor kidney with a similar tissue-type to the recipient is used and the recipient is treated with drugs that suppress the immune system (immunosuppressant drugs)
What does sweating help to do?
Cool the body
More water is lost when it is…
Hot, and more water has to be taken in as drink or food to balance this loss
What is body temperature monitored and controlled by?
The thermoregulatory centre in the brain
What does the thermoregulatory centre of the brain have?
Receptors sensitive to the temperature of the blood flowing through the brain
What do temperature sensors in the skin also do?
Send impulses to the thermoregulatory centre, giving information about skin temperature
What happens in blood vessels if the core temperature is too high?
Blood vessels supplying the skin capillaries dilate so that more blood flows through the capillaries and more heat is lost
What happens in sweat glands if the core temperature is too high?
Sweat glands release more sweat which cools the body as it evaporates
What happens in the blood vessels if the core temperature is too low?
Blood vessels supplying the skin capillaries constrict to reduce the flow of blood through the capillaries
What happens in the muscles if the core temperature is too low?
The muscles may shiver, their contraction needs respiration, which releases some energy to warm the body
What is the blood glucose concentration monitored and controlled by?
The pancreas
What hormone does the pancreas produce?
Insulin
What does insulin allow the glucose to do?
Move from the blood into the cells
When is glucagon produced?
It is produced in the pancreas when blood glucose levels fall
What does glucagon cause?
Glycogen to be converted into glucose and to be released into the blood
What is type 1 diabetes?
A disease in which a person’s blood glucose concentration may rise to a high level because the pancreas does not produce enough of the hormone insulin
How can type 1 diabetes be controlled?
By careful attention to diet, exercise and by injecting insulin
