Homeostasis Flashcards
What is homeostasis?
Maintenance of a constant, internal environment
Why is homeostasis important?
So that the body continues to function optimally. If conditions within the body change too much, it can lead to death.
What is thermoregulation?
Maintenance of constant body temperature
Why is thermoregulation important?
Changes in body temperature can impact the function of enzymes, causing them to work slower or denature.
What is osmoregulation?
Maintenance of a constant level of water in the body
Why is osmoregulation important?
Changes in water level in the body can cause body cells to lose or gain water by osmosis, leading to them becoming shriveled or bursting.
When is sweat released? How does it work?
Released when we are too hot. Sweat moves onto the surface of the skin and evaporates, taking heat energy with it.
What changes happen in the body when we get too cold?
Shivering, hairs stand up, vasoconstriction, no sweat produced
What changes happen in the body when we get too hot?
no shivering, hairs lie flat, sweating, vasodilation.
Which part of the brain coordinates the thermoregulatory response?
hypothalamus
What is vasodilation? When does it happen? How does it work?
Vasodilation is where blood vessels close to the skin widen, allowing more blood to flow through. It happens when we are hot and allows the more heat to radiate from the blood to the environment
What is vasoconstriction? When does it happen? How does it work?
Vasoconstriction is where blood vessels close to the skin become narrow, meaning blood cannot pass through. It happens when we are cold and means the blood is more insulated from the environment so less heat is lost.
Name 3 ways water leaves our body
breathing, sweating, urinating
Which organ in the body removes excess water from the blood?
Kidneys
Other than water, which other waste substance is removed from the body by kidneys?
Urea
What happens to nutrients such as glucose which are filtered out of the blood by the kidneys?
Reabsorbed back into the blood
Why isn’t protein filtered out of the blood in the kidneys?
Molecules are too large
What are the filtering units in the kidneys called?
nephrons
Which part of the brain detects changes in water concentration in the blood?
hypothalamus
Which gland releases the hormone responsible for controlling water concentration in the blood?
pituitary gland
Which hormone is responsible for controlling water concentration in the blood?
ADH
What is the target organ for ADH?
Kidneys
What effect does ADH have on the kidneys?
causes the kidney tubule to become more permeable, so more water is reabsorbed into the blood
When is ADH released?
When there is too little water in the blood.
What happens when there is too much water in the blood?
the hypothalamus detects the change and stimulate the pituitary gland to release less ADH. Less ADH means the kidneys are less permeable to water so less is reabsorbed and more is removed in urine.
What happens when there is too little water in the blood?
The hypothalamus detects the change and stimulates the pituitary gland to release more ADH. More ADH means the kidneys are more permeable to water so more is reabsorbed and less is removed in urine.
What are two treatments for kidney disease?
Dialysis or kidney transplant
What happens during dialysis?
blood is filtered through a machine which acts like a kidney, filtering excess water, ions and urea from the blood.
What are some disadvantages of dialysis?
Patients of dialysis will need the procedure carried out 2-3 times per week and it takes 4-6 hours each time. Patients also need to carefully control their diet and water intake. Dialysis only works for a certain amount of time.
What are some disadvantages of having a kidney transplant?
Any operation carries risks of infection or complications. The operation is expensive for the NHS. There is a shortage of organ donors. An organ donor has to be a match and even then the patient needs to take immune-suppressant drugs which increase chance of infection. Transplanted kidneys only last 8-9 years on average.
Where in the body is urea produced?
liver
What is urea made from?
Broken down excess amino acids
