L9+10 Renal and ...

Question 1

What is the structural and functional unit of the kidney?

Answer 1

The nephron.

Question 2

What substances are NOT filtered by the nephron?

Answer 2

Red blood cells and plasma proteins.

Question 3

Name the components of the nephron in order.

Answer 3

Glomerulus, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.

Question 4

What percentage of cardiac output is processed by the kidneys?

Answer 4

Approximately 22-25%.

Question 5

Define reabsorption in the context of kidney function.

Answer 5

The process where substances exit the nephron and return to circulation via the peritubular capillaries.

Question 6

Define secretion in the context of kidney function.

Answer 6

The process where substances enter the nephron from outside (e.g., from peritubular capillaries or interstitial space).

Question 7

How is creatinine removed from the blood?

Answer 7

Primarily by glomerular filtration, with some removal by proximal tubular secretion.

Question 8

Why is creatinine used as a measure of kidney health?

Answer 8

Because it’s released at a constant rate by the body and little or no tubular reabsorption occurs.

Question 9

What happens when sodium is reabsorbed from the nephron?

Answer 9

Water follows (due to osmosis), increasing blood volume.

Question 10

How is urea formed in the body?

Answer 10

The liver combines ammonia (from amino acid breakdown) with CO₂ to produce urea.

Question 11

How do kidneys regulate pH during acidaemia (low pH)?

Answer 11

By secreting and removing excess hydrogen ions and reabsorbing more bicarbonate ions into circulation.

Question 12

How do kidneys regulate pH during alkalaemia (high pH)?

Answer 12

By excreting excess bicarbonate ions and secreting less hydrogen.

Question 13

What receptors detect increased blood vessel distension when blood volume increases?

Answer 13

Baroreceptors (located in the aorta arch and carotid sinus).

Question 14

How does decreased ADH affect the body?

Answer 14

It increases urinary water loss.

Question 15

What causes hyponatraemia?

Answer 15

Low sodium levels in the blood, often due to excessive water intake or conditions causing water retention.

Question 16

Name four conditions that can cause prolonged hyponatraemia.

Answer 16

1) Hypothalamic-kidney feedback loop overwhelmed by increased fluid intake 2) Feedback loop malfunction (ADH always ‘turned on’) 3) Kidney receptors always ‘open’ regardless of ADH signal 4) Increased ADH without normal stimulus

Question 17

How do diuretics work?

Answer 17

By blocking reabsorption of sodium and water, increasing urine output and reducing fluid volume.

Question 18

What side effect can loop and thiazide diuretics cause?

Answer 18

Hypokalaemia (low potassium levels).

Question 19

What are the three classifications of acute renal failure causes?

Answer 19

Pre-renal, intra-renal/intrinsic, and post-renal.

Question 20

What is pre-renal acute renal failure?

Answer 20

Obstruction in blood flow to kidneys leading to hypoperfusion and hypoxic kidney injury.

Question 21

What is post-renal acute renal failure?

Answer 21

Obstruction in the flow of urine (e.g., from kidney stones) causing damage to filtering structures.

Question 22

What is intra-renal/intrinsic acute renal failure?

Answer 22

Direct damage to the filtering structures of the kidney, often from inflammation.

Question 23

What percentage of acute renal failure cases does acute tubular necrosis make up?

Answer 23

Approximately 75%.

Question 24

What organism typically causes UTIs?

Answer 24

Escherichia coli (E. coli).

Question 25

Why are women more anatomically vulnerable to UTIs than men?

Answer 25

Women have shorter urethras, while men have longer urethras and prostatic fluid that acts as an antibacterial shield.

Question 26

How do UTIs typically progress through the urinary system?

Answer 26

They are ascending in nature, arising from organisms in the perineal area and travelling along continuous mucosa to the bladder, where they multiply, and can travel to the kidneys.

Question 27

What is pyelonephritis?

Answer 27

A kidney infection, typically caused by bacterial infection extending from the ureter into the kidney.

Question 28

What is glomerulonephritis and what typically causes it?

Answer 28

Bilateral inflammation of glomeruli, typically following a streptococcal infection.

Question 29

What is hydronephrosis?

Answer 29

Dilation of the renal pelvis and calyces from the back pressure of urine caused by obstruction.

Question 30

What is the most common composition of kidney stones?

Answer 30

Calcium salts (approximately 75% of cases).

Question 31

Name the three stages of chronic renal failure.

Answer 31

1) Decreased renal reserve, 2) Insufficiency, 3) End-stage renal failure (uraemia).

Question 32

At what point of nephron loss do clinical signs of kidney disease typically appear?

Answer 32

After more than 60% of nephrons are lost (symptoms usually appear during insufficiency stage).

Question 33

What is uraemia?

Answer 33

High levels of urea in the blood, occurring in end-stage renal failure.

Question 34

How does chronic kidney disease affect vitamin D?

Answer 34

Reduces activation of vitamin D, leading to reduced calcium absorption from intestines.

Question 35

How does chronic kidney disease affect bone health?

Answer 35

Low calcium levels trigger parathyroid hormone production, which breaks down bone calcium, weakening bones (osteodystrophy).

Question 36

What are the two main types of dialysis?

Answer 36

Haemodialysis and peritoneal dialysis.

Question 37

How often is haemodialysis typically performed?

Answer 37

Usually 3 times weekly, 3-4 hours per session.

Question 38

How does peritoneal dialysis work?

Answer 38

By pumping dialysis fluid into the peritoneum, allowing exchange of wastes and electrolytes from blood vessels into the peritoneal cavity via osmosis.

Question 39

What is a common complication of peritoneal dialysis?

Answer 39

Infection causing peritonitis.

Question 40

What is an arteriovenous fistula and what is it used for?

Answer 40

A surgical connection between an artery and vein (usually in the arm) that provides vascular access for haemodialysis.