Lecture 11 - 12

Question 1

List some of the anatomy involved in the Kidneys and Urinary System

Answer 1

• Cortex
• Bowmans Capsule
• Glomerulus
• Medulla

Question 2

What is the function of the Glomerulus?

Answer 2

Key structure that allows the filtration of the blood

Question 3

List the 3 Key Principles for Renal Function

Answer 3

1) Glomerular Filtration
2) Tubular Secretion
3) Tubular Reabsorption

Question 4

What is the basic formula for renal excretion?

Answer 4

Excreted = filtered + secreted - reabsorbed

Question 5

What are the three major kidney functions?

Answer 5

1) Regulate hydration (blood volume)
2) Acid-base balance (H⁺)
3) Electrolyte balance

Question 6

What forces drive glomerular filtration?

Answer 6

Starling forces: hydrostatic pressure (PGC) and osmotic pressure (πGC)

Question 7

What is a normal glomerular filtration rate (GFR)?

Answer 7

About 125 mL/min or 180 L/day

Question 8

What does a rise in plasma creatinine indicate?

Answer 8

Decreased GFR and impaired kidney function

Question 9

What happens to toxins, glucose, and Na⁺/K⁺ in renal processing?

Answer 9

• Toxins: fully excreted
• Glucose: fully reabsorbed
• Na⁺/K⁺: regulated (partially reabsorbed)

Question 10

How is tubular secretion different from reabsorption?

Answer 10

• Secretion moves substances into the tubule lumen
• Reabsorption moves substances back into blood

Question 11

What are common oral manifestations of chronic kidney disease (CKD)?

Answer 11

• Pallor
• Ulcers
• Loose teeth
• Increased infection risk

Question 12

What is the basic functional unit of the kidney?

Answer 12

Nephron

Question 13

What part of the nephron filters blood?

Answer 13

Renal corpuscle (Glomerulus + Bowman’s capsule)

Question 14

Which molecules are normally NOT filtered at the glomerulus?

Answer 14

Large proteins like albumin

Question 15

What drives glomerular filtration pressure?

Answer 15

High hydrostatic pressure in the glomerular capillaries (PGC)

Question 16

What happens to GFR if afferent arteriole constricts?

Answer 16

GFR decreases

Question 17

What happens to GFR if efferent arteriole constricts?

Answer 17

GFR increases (up to a point)

Question 18

Why is creatinine used clinically to estimate GFR?

Answer 18

It is freely filtered, minimally secreted, and not reabsorbed

Question 19

What happens to plasma creatinine if kidney function worsens?

Answer 19

Plasma creatinine levels rise

Question 20

What are oral health impacts of CKD?

Answer 20

• Increased infections
• Pale mucosa
• Bleeding
• Loose teeth

Question 21

What is a major systemic complication of CKD?

Answer 21

Hyperkalemia leading to potential cardiac arrhythmias

Question 22

What drives passive water reabsorption in the nephron?

Answer 22

Osmotic gradient established by active Na⁺ reabsorption

Question 23

Where does most water reabsorption occur in the nephron?

Answer 23

Proximal tubule

Question 24

What are the 3 GFR determinants?

Answer 24

1) Glomerular filtration pressure - relative high PGC
2) Permeability of corpuscular membranes (high)
3) Surface area (Large)

Question 25

What products are involved in Tubular Secretion?

Answer 25

- H+ - K+ - Choline - Penicillin - Creatinine

Question 26

What products are involved in Tubular Resabsorption?

Answer 26

- Na+ - Glucose - Vitamin C

Question 27

What are the substance properties to be suitable for GFR determination?

Answer 27

- Freely filtered - Not secreted - Not reabsorbed - Not metabolised - Not toxic

Question 28

What is the GFR for a female?

Answer 28

88 –128 mL/min

Question 29

What is the GFR for a male?

Answer 29

97 –137 mL/min

Question 30

What hormone regulates water reabsorption in the collecting ducts?

Answer 30

Vasopressin (antidiuretic hormone, ADH)

Question 31

What does ADH or VP do?

Answer 31

- Regulates water balance in the body by controlling how much water the kidneys reabsorb - Regulates blood pressure and sodium levels

Question 32

What does VP produce?

Answer 32

Produces Aquaporins: the Aquaporins allow permeability, which means that the more aquaporins we have, then more water can be reabsorbed

Question 33

How does the loop of Henle concentrate urine?

Answer 33

By creating a hyperosmotic medullary interstitium through the counter-current multiplier

Question 34

What are the three major types of diuretics?

Answer 34

1) Loop diuretics (inhibit NKCC) 2) Thiazides (inhibit NCC) 3) Amiloride (inhibits ENaC)

Question 35

What is the effect of aldosterone on sodium balance?

Answer 35

Increases Na⁺ reabsorption via ENaC channels and Na⁺/K⁺ ATPase - Increase plasma volume and blood pressure rises

Question 36

How does atrial natriuretic peptide affect Na⁺ excretion?

Answer 36

Increases Na⁺ excretion by inhibiting reabsorption and increasing GFR

Question 37

What happens to pH in respiratory acidosis?

Answer 37

- pH decreases (more H⁺) - Kidneys compensate by increasing HCO₃⁻ reabsorption

Question 38

What happens to pH in metabolic alkalosis?

Answer 38

- pH increases (less H⁺) - Lungs compensate by hypoventilating to retain CO₂

Question 39

What should NOT be present in normal urine?

Answer 39

- Glucose - Proteins - Blood - Haemoglobin - Leukocytes - Bacteria

Question 40

How can mercury exposure from dental amalgam affect kidneys?

Answer 40

Accumulates in tubular cells causing nephrotoxicity

Question 41

What happens to urine output when vasopressin levels are high?

Answer 41

Urine volume decreases (more concentrated)

Question 42

What inhibits vasopressin secretion?

Answer 42

Alcohol (ethanol)

Question 43

What is the function of the ascending limb of the Loop of Henle?

Answer 43

Actively reabsorbs Na⁺ and Cl⁻, but is impermeable to water

Question 44

Why is the medullary interstitium hyperosmotic?

Answer 44

Due to Na⁺ and Cl⁻ reabsorption in the ascending limb

Question 45

What does furosemide (loop diuretic) inhibit?

Answer 45

NKCC (Na⁺-K⁺-2Cl⁻ cotransporter)

Question 46

What is the effect of amiloride?

Answer 46

Inhibits ENaC (epithelial Na⁺ channel) in collecting ducts

Question 47

What triggers renin release?

Answer 47

Low blood pressure, sensed by baroreceptors or macula densa

Question 48

What is the main effect of aldosterone?

Answer 48

Increases Na⁺ reabsorption in the collecting duct

Question 49

What does ANP do to GFR?

Answer 49

Increases GFR by dilating afferent and constricting efferent arterioles

Question 50

How does the kidney compensate for respiratory acidosis?

Answer 50

Increases HCO₃⁻ reabsorption

Question 51

How does the kidney compensate for respiratory alkalosis?

Answer 51

Increases HCO₃⁻ secretion

Question 52

What happens in metabolic acidosis?

Answer 52

Ventilation increases to blow off CO₂

Question 53

What happens in metabolic alkalosis?

Answer 53

Ventilation decreases to retain CO₂

Question 54

What components indicate pathological urine?

Answer 54

- Glucose (diabetes) - Proteins (proteinuria) - Blood (hematuria) - Bacteria (infection)

Question 55

How does diabetes affect urine appearance and smell?

Answer 55

Sweet taste; fruity smell due to ketosis

Question 56

How does mercury exposure from dental amalgam affect kidneys?

Answer 56

Mercury accumulates in renal tubular cells, causing nephrotoxicity

Question 57

What do Thiazides do?

Answer 57

- Inhibits NCC - Controls 5% water reabsorption, mild diuresis - No effect on K+

Question 58

What does Amiloride do?

Answer 58

- Inhibits ENaC - Controls 3% water re-absorption very mild diuresis - No effect on K+

Question 59

What does Natriuresis do?

Answer 59

- Increase in Na+ excretion due to osmotic diuresis - Plasma volume decrease, blood pressure drops

Question 60

What is Acidosis?

Answer 60

- Increase of arterial H+ - Arterial pH < 7.4

Question 61

What is Alkalosis

Answer 61

- Decrease of arterial H+ - Arterial pH > 7.4

Question 62

What is the compensation for Metabolic Acidosis?

Answer 62

Increase of ventilation (to decrease PCO2 and lower blood H+)

Question 63

What is the compensation for Metabolic Alkalosis?

Answer 63

- Decrease of ventilation (to increase PCO2 and increase blood H+) - Alternative: increase secretion of HCO3- (kidney)