B12. Homeostasis in action Flashcards
What happens to body cells if they lose or gain too much water by osmosis?
If body cells lose or gain too much water by osmosis, they do not function efficiently: too much water can cause cell lysis and too little water can lead to cell death
What are the two sources of water in the body?
The two sources of water in the body are water produced as a result of aerobic respiration and water in the diet
How is water lost from body?
Via the lungs during exhalation
Through the skin in sweat
Controlled loss via the kidneys when they filter the blood to produce urine
Define deamination
Deamination is the process of breaking down excess proteins in the liver, where enzymes split up amino acid molecules, converting the nitrogen-containing part into ammonia, which is then converted to urea for safe excretion
What is the role of kidneys in the body?
The kidneys help to control the water content of the body and the concentrations of substances (such as sodium and potassium ions) dissolved in the body fluids
What is filtration in the kidneys?
Filtration is the process where high-pressure mass flow forces small molecules like glucose, urea and water with ions out of the bloodstream into the kidneys, forming filtrate
What happens during selective reabsorption in the kidneys?
During selective reabsorption, substances needed by the body are reabsorbed back into the bloodstream from the filtrate in
What forms urine in the kidneys?
Urine is formed from substances not reabsorbed from the filtrate, including urea, water, and excess ions
What is the role of ADH in the control of water levels?
More ADH makes the tubules more permeable, leading to more water reabsorption when blood water content is low (urine is concentrated)
Less ADH makes the tubules less permeable when the blood water content is high
Define kidney failure
A condition where the kidneys do not function properly, leading to a build-up of toxic wastes in the body, which can be fatal if not treated
What is dialysis?
A treatment for kidney failure where a machine acts as an artificial kidney, removing most of the urea and maintaining the water and salt balance in the blood
What is a kidney transplant?
A surgical procedure where a healthy kidney from a donor is implanted into a patient with kidney failure, offering a long-term solution compared to dialysis
What are advantages of a kidney transplant over dialysis?
More freedom to the patient
A less restrictive diet
Lower cost option
Long-term solution
What are the disadvantages of kidney transplants?
Risk of rejection
The need for lifelong immunosuppressant drugs with side effects
Shortage of donors
In what ways are ions lost from the body?
Sweating
Urine (some reabsorbed in the kidney)
