Homeostasis Flashcards
How is carbon dioxide removed?
By the lungs
What waste products must the body remove?
Carbon dioxide
Urea
How is urea produced?
By the liver when it breaks down amino acids
What internal conditions must be carefully monitored?
Temperature
Water content
Ion content
Blood sugar
How is water lost?
By breathing
Sweating
Excess in urine
How is ion content reduced?
By the kidneys in urine
What is the danger of too much water or ion content?
Too much water may move in and out of cells which could damage them
What system are the kidneys part of?
Urinary
What are the functions of the kidneys?
Clean the blood by removing urea
Maintain concentration of dissolved substances (sugar, ions)
Maintain water level
How is urine produced?
Blood is filtered. Water, ions, urea and sugar pass into kidney tubules
SELECTIVE REABSORPTION absorbs useful substances (ions and sugars which may have to use active transports)
Urea, excess ions and water stay in tubules
Pass into bladder
How can kidney failure be treated?
Dialysis
Kidney transplant
How does a dialysis machine work?
Blood is separated by partially permeable membrane in machine
Membrane allows urea and excess substances to pass to the dialysis fluid
How do dialysis machines ensure that glucose and ions are not lost?
Have same concentration gradients as useful substances in blood
What precautions must be taken to reduce risk of kidney rejection?
Tissue type must be as close as possible
Immunosuppressants
Why might the body reject a kidney after transplant?
Antibodies may attack them because they don’t recognise them
What temperature should the body be kept around?
37°C
Why must the body be kept at this temperature?
Allows enzymes to work best
How is body temperature controlled?
Thermoregulatory centre
Has receptors that are sensitive to temperature of blood flowing through it
Temperature receptors in skin
Send impulses to thermoregulatory centre
If the body gets too hot, how is the temperature controlled?
Capillaries dilate allowing more heat to be lost through skin
Sweat glands release sweat
Hairs lie flat
If the body gets too cold, how is the temperature controlled?
Capillaries constrict
Muscles shiver causing heat energy to be released via respiration
Hairs stand up
What part of the body controls the blood sugar concentration?
Pancreas
What does insulin do?
Allows blood to move from the blood into the cells
Causes liver to convert excess glucose to glycogen
What is released when blood glucose levels are too high?
Insulin
What is glycogen?
An energy store
What does glucagon do?
Causes glycogen to be converted into glucose and released into the blood
What is released when blood glucose levels fall?
Glucagon
What is type 1 diabetes?
Person’s glucose concentration may be too high as pancreas doesn’t produce enough insulin
How can type 1 diabetes?
Be careful about what they eat
Be careful about when and how much exercise is taken in
Insulin injections
What are the benefits of dialysis?
Always available for people waiting for a transplant
No rejection
What are the problems with dialysis?
Long sessions
Controlled diet
Regular sessions
What are the benefits of kidney transplant?
No dialysis sessions
If tissue type matches, success rate is nearly 80%
Healthy person can donate a kidney and still live
What are the problems with kidney transplants?
Must be donated within 12 hours
Rejection
Anti-rejection drugs for rest of life
Shortage of donors
