HOMEOSTASIS AND KIDNEY

Question 1

Define homeostasis

Answer 1

Maintains internal environment in response to external change

Question 2

Define negative feedback

Answer 2

Change in system producing second change which reverses to first change

Question 3

Define excretion

Answer 3

Removal of nitrogenous metabolic waste from body

Question 4

Define osmoregulation

Answer 4

Control of the water potential of the body fluids by regulating water content therefore solute concentration

Question 5

Describe production of urea

Answer 5

Dietary protein digested into amino acids that are transported in liver and around the body to assimilate into proteins

Any excess amino acids are delaminated by liver and amino group is converted into urea

Question 6

What happens at PCT during selective reabsorption

Answer 6

• all glucose reabsorbed by active transport
• all amino acids , vitamins and hormones reabsorbed by active transport
• some sodium ions reabsorbed by active transport
• causes changes in water potential in filtrate so water leaves via osmosis
• chloride ions leave by diffusion so conc of solutes high in filtrate

Question 7

What happens to Loop of Henle at selective reabsorption

Answer 7

• water reabsorbed by osmosis
• ion conc inside filtrate increases in descending limb
• bottom on loop is hypertonic and salts move out via diffusion
• conc of salts decrease in ascending limb - isotonic
• active transport of salts reabsorbed

Question 8

What happens at DCT during selective reabsorption

Answer 8

• only reabsorbs water or salts when needed to balance out the need and pH of blood

Question 9

What happens at collected duct in selective reabsorption

Answer 9

• water reabsorption by osmosis
• more aquaporins on tubule wall so more water reabsorbed

Question 10

What happens at osmoregulation if water in blood is too high

Answer 10

Signals pituitary gland to release less ADH
Kidneys reabsorb less water
Levels back to normal

Question 11

What happens at osmoregulation is water levels in blood are too low

Answer 11

Signals pituritary gland to release more ADH
Kidneys reabsorb more water
Normal conditions

Question 12

Describe ADH mechanism when dehydrated

Answer 12

• ADH binds to receptors on tubule wall
• triggers cAMP formation in cells from ATP
• cAMP signals vesicles with aquaporin to move and fuse with plasma membrane
• inserts aquaporin on inner wall so increases permiability to water and more water reabsorbed

Question 13

3 reasons that can cause kidney failure

Answer 13

• diabetes
• high blood pressure
• auto immune disease

Question 14

3 ways to treat kidney failure

Answer 14

• diet
• using drugs
• dialysis

Question 15

Process of haemodialysis

Answer 15

• patients blood taken from artery and passes through dialysis machine which removes harmful molecules such as urea
• also adjusts concentrations of other chemicals to within normal range
• blood returned back to

Question 16

How many hours and times a week does dialysis need

Answer 16

Several
3x