Topic 7: The Kidney and Homeostasis

Question 1

What is the role of the kidneys?

Answer 1

To regulate the water content in the blood. (osmoregulation)
To excrete the toxic waste products of metabolism.

Question 2

What is the function of the renal artery? (branching from aorta)

Answer 2

Supplies blood to the kidneys.

Question 3

What is urea?

Answer 3

A waste product resulting from the breakdown of proteins. Excreted in urine.

Question 4

What is urine?

Answer 4

The waste product secreted by the kidneys. Water, salts and urea are in it.

Question 5

What is the bladder’s function?

Answer 5

To store urine until it is convenient to expel it from the body through the urethra.

Question 6

What is a ureter?

Answer 6

The tube leading from the kidney to the bladder. Takes urine to bladder.

Question 7

What is the function of the renal vein? (branching from vena cava)

Answer 7

Drain blood from the kidneys.

Question 8

What is osmoregulation?

Answer 8

A type of homeostasis that maintains constant water levels in body fluids.

Question 9

Why is osmoregulation important?

Answer 9

Prevents cells from bursting or shrinking when water enters/leaves my osmosis.

Question 10

What is a urethra?

Answer 10

This tube allows urine to pass outside the body.

Question 11

What is the cortex?

Answer 11

The outer layer of the kidney.

Question 12

What are the medulla?

Answer 12

The inner most part of the kidney.

Question 13

What is the pelvis and where does it lead?

Answer 13

A large cavity that collects the urine as it is produced and leads to the ureter.

Question 14

Where are the nephrons positioned?

Answer 14

With the capillary knot in the cortex and the loop of henle going into the medulla.

Question 15

Where is the arterioles to/from capillary knot, capillary knot, bowman’s capsule, tubule, network of capillaries and collecting duct on a nephron?

Answer 15

Use a diagram to name them.

Question 16

What is the purpose of the nephrons?

Answer 16

To extract wastes from the blood to produce urine.

Question 17

What are the 3 main processes in the nephron?

Answer 17

Ultrafiltration, selective reabsorption and regulation of water content.

Question 18

What are the arterioles?

Answer 18

Small blood vessels that connect the arteries to the capillaries.

Question 19

Why is there high pressure in the capillary knot?

Answer 19

The diameter of the arteriole leaving the knot is narrower than the arteriole entering. Only small molecules can leave.

Question 20

What small molecules leave the blood and what molecules stay in the blood to filtration?

Answer 20

Proteins and cells leave through the arteriole with blood as they can’t fit through the walls of capillaries while water, glucose, salts and urea stay to flow through the bowman’s capsule.

Question 21

What is ultrafiltration?

Answer 21

The process where the capillary knot filters water, glucose, salts and urea from the blood.

Question 22

Where does selective reabsorption occur?

Answer 22

Throughout the tubule.

Question 23

What molecules are selectively reabsorbed into the bloodstream?

Answer 23

Glucose, some water and some salts.

Question 24

What fluid is left after filtration and selective reabsorption?

Answer 24

Urine which a mix of: (mainly) urea, water and salts.

Question 25

What does ADH stand for?

Answer 25

Anti-diuretic hormone.

Question 26

What part of the body identifies that ADH must be released?

Answer 26

The pituitary gland. | Located just beneath, but attached to, the brain).

Question 27

What does ADH do?

Answer 27

A hormone produced that causes the kidneys to release less water, decreasing the amount of urine produced.

Question 28

What happens if the blood is too dilute? (checked in nephron)

Answer 28

There will be a higher percentage of water in the urine because less water needs to be reabsorbed into the blood.

Question 29

What happens if the blood doesn't have enough water? (checked in nephron)

Answer 29

Less water will be in the urine as more will be reabsorbed into the blood to maintain the balance. This makes the urine more concentrated and dark.

Question 30

What happens if the concentration of the blood is too high?

Answer 30

ADH is produced which will cause the kidney to reabsorb more water and produce a more concentrated urine.

Question 31

What happens if the concentration of the blood is too low?

Answer 31

ADH is not produced, so there is no signal to reabsorb more water.

Question 32

What is the process of ADH an example of?

Answer 32

Negative feedback.

Question 33

If there is glucose in the urine, how is it there and what disease can be identified?

Answer 33

There is so much glucose in the blood (no insulin) that it must be excreted through urine. Diabetes (type 1 or 2) can be identified.

Question 34

If there is protein in urine, what can be identified (and why)?

Answer 34

That there is damage in the kidney due to proteins usually being too large to fit through the bowman's capsule of a nephron.

Question 35

What are the 2 ways to treat kidney failure?

Answer 35

Kidney dialysis. | Kidney transplant.

Question 36

What is kidney dialysis?

Answer 36

An artificial kidney machine which patients must be attached to for long hours in the day. It removes wastes and restores the balance of salts and water in the blood.

Question 37

What is a kidney transplant?

Answer 37

The process of placing a new kidney in the body, to make sure kidney function is restored.

Question 38

What are 2 advantages of kidney dialysis?

Answer 38

1. It can keep a patient alive whilst they are waiting for a donor. 2. It does not involve the major risks of surgery.

Question 39

What are 3 disadvantages of dialysis?

Answer 39

1. The patient must spend many hours of the day hooked up to it, can't have full time job. 2. Strict diet, they must restrict fluid and salt intake between sessions. 3. Dialysis machines are expensive.

Question 40

What is the process in a dialysis machine? (4 stages)

Answer 40

1. Blood (taken from arm) and dialysate is pumped through machine. 2. Dialysate / blood separated by selectively permeable membrane, only lets small molecules through. 3. Salts and water use diffusion and osmosis to enter dialysate (it has less salts and water than blood). 4. Dialysate constantly renewed.

Question 41

What is dialysate?

Answer 41

A solution containing water and salts (but less than blood so osmosis and diffusion can occur).

Question 42

What are 3 advantages of kidney transplants?

Answer 42

1. Once transplant happens, patient no longer has diet restrictions. 2. Dialysis are not needed anymore. 3. Though not life-long cure, much more normal life than dialysis patient.

Question 43

What are 5 disadvantages of kidney transplants?

Answer 43

1. It is difficult to find a donor organ with a matching tissue type. 2. The risk of organ rejection. 3. Must take drugs to suppress the immune system. Patient vulnerable to other diseases. 4. Regular doctors' appointments to detect signs of organ rejection. 5. Major surgery required.