Biology 3 - Role of kidneys in homeostasis Flashcards
What is homeostasis?
Keeping internal environment constant
Which body things must be kept constant?
Water content
Waste chemicals (must be removed)
Body temp
Glucose levels
What do the kidneys control?
Removal of urea
Water content
Removal of excess mineral salts
What is the term for removing waste from the body?
Excretion
How does blood
A) enter the kidney
B) leave the kidney
A) renal artery
B) renal vein
What’s the name of the tube that carries urine from the kidney to the bladder?
Ureter
Which tube carries urine out the body (from the bladder)?
Urethra
What is the term for the
A) outer layer of the kidney
B) inner layer of the kidney
A) cortex
B) medulla
What do nephrons do?
Remove urea, excess mineral salts and water from the blood to make urine
What is urine made from?
Water, urea and mineral salts
What are the two stages of production of urine by the nephron?
- Ultrafiltration
2. Reabsorption
What does ultrafiltration involve?
Filtration of small molecules under pressure from the capillary knot into the Bowman’s capsule
What does reabsorption involve?
Useful substances such as glucose and amino acids are reabsorbed into the blood in the capillary network
Some excess mineral salts and water is reabsorbed too
Why isn’t there any proteins or red blood cells in urine?
They’re too large to be filtered out the blood
Why is there no glucose in urine?
It’s all been reabsorbed
What would blood in urine indicate?
Kidney disease
What is water balance?
When the amount of water taken in and lost is equal
Name 2 ways we gain water
Drinking
Eating
Name 2 ways we lose water
Exhaling
Sweating
(Could also have urinating)
What is the term for controlling the amount of water concentration in the blood?
Osmoregulation
How is osmoregulation controlled?
By the anti diuretic hormone (ADH) - released by brain, carried by blood to kidneys
What would happen to the concentration of urine if you drank too much water? Why?
Would become more dilute because brain secretes less ADH so less water is absorbed back into the blood
Name 2 possible ways of treating kidney failure
- Kidney dialysis
2. Organ transplant
What is the aim of dialysis?
To restore the concentrations of dissolved substances in the blood to normal levels (basically it’s an artificial kidney)
How does the dialysis machine work?
Blood flows between ppm which ensures glucose and salts aren’t lost
The dialysis fluid contains the same concentration or useful substances as plasma so only urea, excess mineral salts and water will diffuse
Blood returns to patient
How can you reduce the chances of rejection
A) before a transplant
B) after a transplant
A) donor has similar tissue type eg family member
B) take drugs to suppress immune system
What are the advantages of dialysis?
No problems with rejection
No surgery required
What are the disadvantages of dialysis?
Have to do it a lot
Only temporary
What are the advantages of transplants?
Potential cure for many years
No diet restrictions
Don’t have to visit hospital a lot
What are the disadvantages of transplants?
Major surgery
Have to take drugs to suppress immune system
Kidney may be rejected
What are the ethical issues surrounding transplants?
Buying and selling of organs
Presumed consent of (living) donors
Xenotransplantation (between different species)
