Renal 1

Question 1

What are the main components of the renal system?

Answer 1

The renal system consists of the kidneys, ureters, bladder, and urethra.

Question 2

What is the primary function of the kidneys?

Answer 2

The kidneys filter blood to form urine, regulate fluid balance, electrolyte concentrations, blood pressure, acid-base balance, and produce hormones like erythropoietin and renin.

Question 3

Describe the flow of blood through the kidneys.

Answer 3

Renal artery → Afferent arteriole → Glomerulus → Efferent arteriole → Peritubular capillaries/vasa recta → Renal vein

Question 4

What are the 3 main processes involved in urine formation?

Answer 4

1. Filtration – Occurs at the glomerulus, where plasma is filtered into Bowman’s capsule.
2. Reabsorption – Useful substances (e.g., glucose, water, electrolytes) are reabsorbed into the blood.
3. Secretion – Waste products (e.g., H⁺, K⁺, drugs) are actively transported into the nephron.

Question 5

What are the two types of nephrons and their differences?

Answer 5

• Cortical nephrons (85%) – Short loop, primarily in the cortex, surrounded by peritubular capillaries.
• Juxtamedullary nephrons (15%) – Long loop of Henle, extends deep into the medulla, surrounded by vasa recta, critical for concentrated urine formation.

Question 6

The kidneys receive 20-25% of

Answer 6

cardiac output (~1.25 L/min).

Question 7

~20% of the plasma is filtered at the

Answer 7

glomerulus; most is reabsorbed, leaving ~1.5 L of urine daily.

Question 8

Nephrons are the functional unit of the

Answer 8

kidney (~1 million per kidney).

Question 9

The Na⁺/K⁺-ATPase on the basolateral membrane maintains

Answer 9

Na⁺ gradients for reabsorption.

Question 10

Filtration at the glomerulus is driven by

Answer 10

hydrostatic pressure.

Question 11

Erythropoietin stimulates red blood cell production in response to

Answer 11

hypoxia.

Question 12

The kidneys play a key role in maintaining acid-base balance by

Answer 12

excreting H⁺ and reabsorbing HCO₃⁻.

Question 13

The kidneys are intraperitoneal organs.

Answer 13

False (They are retroperitoneal, located behind the peritoneum.)

Question 14

Juxtamedullary nephrons are essential for concentrated urine formation.

Answer 14

True

Question 15

All glucose in the filtrate is excreted in the urine.

Answer 15

False (Glucose is normally completely reabsorbed in the proximal convoluted tubule.)

Question 16

The glomerular filtration rate (GFR) is primarily determined by hydrostatic and osmotic pressures.

Answer 16

True

Question 17

The kidneys are responsible for producing active vitamin D (calcitriol).

Answer 17

True

Question 18

The ______ is the functional unit of the kidney.

Answer 18

Nephron

Question 19

The three main processes of urine formation are ______, ______, and ______.

Answer 19

Filtration, Reabsorption, Secretion

Question 20

______ nephrons have a long loop of Henle and are surrounded by the vasa recta.

Answer 20

Juxtamedullary

Question 21

______ cells in the juxtaglomerular apparatus secrete renin in response to low sodium.

Answer 21

Juxtaglomerular granular

Question 22

The ______ is the site of ultrafiltration, consisting of fenestrated capillaries.

Answer 22

Glomerulus

Question 23

Which of the following is NOT a function of the renal system?
A) Regulation of blood pressure
B) Production of insulin
C) Osmoregulation
D) Excretion of metabolic waste

Answer 23

B) Production of insulin (The pancreas produces insulin, not the kidneys.)

Question 24

What structure in the nephron is responsible for detecting Na⁺ levels in the tubular fluid?
A) Glomerulus
B) Macula densa
C) Podocytes
D) Collecting duct

Answer 24

B) Macula densa

Question 25

Which factor affects glomerular filtration? A) Hydrostatic pressure B) Colloid osmotic pressure C) Membrane permeability D) All of the above

Answer 25

D) All of the above

Question 26

What hormone increases water reabsorption in the collecting duct? A) Insulin B) Aldosterone C) Antidiuretic hormone (ADH) D) Glucagon

Answer 26

C) Antidiuretic hormone (ADH)

Question 27

What is the primary function of the loop of Henle? A) Glucose reabsorption B) Acid-base balance C) Concentration of urine D) Filtration of blood

Answer 27

C) Concentration of urine

Question 28

Scenario 1: A patient is diagnosed with acute kidney injury (AKI), leading to decreased glomerular filtration rate (GFR). What would happen to waste products like urea and creatinine?

Answer 28

Answer: Reduced GFR would lead to accumulation of waste products in the blood, causing azotemia (high urea and creatinine levels).

Question 29

Scenario 2: A person becomes dehydrated and has low blood volume. How would the kidneys respond to restore homeostasis?

Answer 29

Answer: The kidneys would increase renin secretion, activating the renin-angiotensin-aldosterone system (RAAS), leading to Na⁺ and water retention to restore blood volume.

Question 30

Scenario 3: A diabetic patient has persistent glucose in their urine (glycosuria). What does this suggest about renal function?

Answer 30

Answer: Glycosuria suggests that the renal glucose transporters in the proximal tubule are saturated, leading to glucose excretion in urine, which is common in uncontrolled diabetes mellitus.

Question 31

Glomerular filtration rate (GFR):

Answer 31

The rate at which plasma is filtered at the glomerulus (~125 mL/min).

Question 32

Nephron:

Answer 32

The functional unit of the kidney responsible for urine formation.

Question 33

Macula densa:

Answer 33

Specialized cells that detect Na⁺ levels in the distal tubule and regulate renin release.

Question 34

Juxtaglomerular cells:

Answer 34

Cells in the afferent arteriole that secrete renin.

Question 35

Erythropoietin:

Answer 35

A hormone produced by the kidneys that stimulates red blood cell production.

Question 36

Renin:

Answer 36

An enzyme involved in blood pressure regulation and sodium balance.

Question 37

Podocytes:

Answer 37

Specialized cells in the Bowman’s capsule that form the filtration barrier.

Question 38

Ultrafiltration:

Answer 38

The process of filtering plasma through the glomerulus into Bowman’s capsule.

Question 39

Osmoregulation:

Answer 39

The process of maintaining water and electrolyte balance.