Physiological Roles of the Kidney

Question 1

What are the functions of the urinary system?

Answer 1

• Regulator
• Excretor
• Producer

Question 2

How does the urinary system act as a regulator?

Answer 2

• Electrolyte balance
• Regulation of water
• Inorganic ion balance

Question 3

How does the urinary system act as an excretory?

Answer 3

• Removal of metabolic wastes (from the blood)

- Removal of foreign chemical from body

Question 4

How does the urinary system act as a producer?

Answer 4

• Gluconeogenesis (production of glucose from non carbohydrate source)
• Production of hormones

Question 5

What does electrolyte imbalance leads to?

Answer 5

Disease

Question 6

What happens if there is 1/3 decrease of K+ concentration?

Answer 6

Nerves unable to generate action potential

Question 7

What happens if there is 1/2 decrease in Ca2+ concentration?

Answer 7

Tetanic skeletal muscle concentration

Question 8

What does homeostasis require?

Answer 8

Maintenance of water, pH and electrolytes with narrow range to be conductive to life

Question 9

Where is sodium largely located?

Answer 9

In extracellular fluid

Question 10

What does changes in plasma Na+ affect?

Answer 10

• Plasma volume = blood pressure

- Intracellular fluid composition and volume

Question 11

What is a role of sodium in the kidney?

Answer 11

Determinant in controlling extracellular fluid volume and water distribution

Question 12

What can an imbalance in sodium lead to?

Answer 12

• Hyponatraemia

- Hypernatraemia

Question 13

Where is 98% of potassium located?

Answer 13

Intracellularly

Question 14

How much of potassium is in skeletal muscle?

Answer 14

70%

Question 15

What is vital in the maintenance of potassium balance?

Answer 15

Kidney

Question 16

What is the main role of potassium in the cell

Answer 16

Forms basis of the RMP and excitability of nerve and muscle cells

Question 17

What can occur of an imbalance of potassium?

Answer 17

• Hypokalaemia

- Hyperkalaemia

Question 18

What does alteration of the amount of excretion/reabsorption of key electrolytes do?

Answer 18

• Alter plasma concentration
• Alter interstitial concentration
• Influence cellular function

Question 19

How many different types of aquaporins are there?

Answer 19

8+ sub-types

Question 20

What produces ADH?

Answer 20

Posterior pituitary gland

Question 21

What produces aldosterone?

Answer 21

Adrenal cortex

Question 22

Is ADH or aldosterone a long term effector?

Answer 22

Aldosterone

Question 23

Is ADH or aldosterone a short term effector?

Answer 23

ADH

Question 24

Why does ADH act a short-term effector in response to dehydration?

Answer 24

• Increase in plasma osmolarity
• Increased body loss of water
• Reduced intake of water

Question 25

Why does aldosterone act a long-term response to decrease body fluid volume?

Answer 25

-Loss of both water and salt results in no change of osmolarity

Question 26

Where is atrial natriuretic peptide produced?

Answer 26

Atrial tissue

Question 27

How does atrial natriuretic peptide work?

Answer 27

Inhibits reabsorption of Na+ Inhibiting H20 reabsorption Urine becomes more dilted

Question 28

What is acidosis?

Answer 28

pH<7.35

Question 29

What is alkalosis?

Answer 29

pH>7.45

Question 30

What happens to the CNS + PNS if pH>7.45?

Answer 30

Over excitability - Sensory neurone fire absence of stimulation - Motor neurons cause muscle twitches

Question 31

Are metabolic acids continually produced?

Answer 31

Yes

Question 32

What controls acid-base balance?

Answer 32

- Respiratory system | - Kidney

Question 33

``` Describe acidosis: In terms of -H+ secretion -H- excretion -HCO3- -pH of urine -Compensatory chang in plasma membrane ```

Answer 33

- H+ secretion = increase - H- excretion = increase - HCO3- = zero - pH of urine = acidic - Compensatory change in plasma membrane = alkalisation towards normal

Question 34

``` Describe alkalosis: In terms of -H+ secretion -H- excretion -HCO3- -pH of urine -Compensatory chang in plasma membrane ```

Answer 34

- H+ secretion = decrease - H- excretion = decrease - HCO3- = increase - pH of urine = alkaline - Compensatory change in plasma membrane = acidification towards normal

Question 35

Within which part of the nephron does the following process mainly take place: reabsorption of water and nutrients A. Renal corpuscle B. Proximal tubule C. LoH descending limb D. Distal tubule E. Collecting duct

Answer 35

B

Question 36

Within which part of the nephron does the following process ``` mainly take place: reabsorption of water by ADH A. Renal corpuscle B. Proximal tubule C. LoH descending limb D. Distal tubule E. Collecting duct ```

Answer 36

E

Question 37

Collecting ducts are located within which part of the kidney? ``` A. Cortex B. Medulla C. Renal pyramids D. Renal columns E. Renal pelvis ```

Answer 37

C

Question 38

``` Which of the following statements relating to ADH is correct? A. It increases the permeability of the collecting ducts to water. B. It is secreted in response to low potassium ion in the blood. C. It causes the kidneys to produce a larger volume of very dilute urine. D. It is secreted by the anterior pituitary. E. Its release is insensitive to the osmolarity of interstitial fluid. ```

Answer 38

A

Question 39

In response to increased levels of aldosterone, the kidneys produce... ``` A. a larger volume of urine. B. urine with a higher concentration of sodium ions. C. urine with a lower concentration of potassium ions. D. urine with a lower concentration of sodium ions. E. urine with less glucose. ```

Answer 39

D

Question 40

Which of the following statements relating to the RAAS is correct? A. Renin is released from the macula densa in response to an increase in the GFR B. The macula densa is located within the proximal tubule and monitors filtered Na + C. Juxtaglomerular cells release renin in response to a decrease in filtered Na + D. Renin is released into the filtrate where it increases Na+ and water reabsorption

Answer 40

C

Question 41

``` A drug that inhibits angiotensin converting enzyme (ACE) may lead to: A. less secretion of aldosterone B. increased urinary loss of sodium C. reduction of blood pressure D. B and C only E. A, B, and C ```

Answer 41

E

Question 42

The process of filtration is driven by: ``` A. active transport B. blood osmotic pressure C. blood hydrostatic pressure D. renal pumping E. solvent drag ```

Answer 42

C

Question 43

Measurement of the functions of a nephron reveals a glomerular capillary pressure of 55 mm Hg, and a pressure in the Bowman’s space of 15 mm Hg. Assuming that the Oncotic pressure is 28 mm Hg, and the glomerulus pressure is 2mmHg. What is the net filtration pressure in this case? ``` A. 40 mm Hg B. 14 mm Hg C. 30 mm Hg D. 26 mm Hg E. 100 mm Hg ```

Answer 43

B

Question 44

Autoregulation of the GFR is best described by the following? ``` A. Myogenic vasoconstriction of afferent arteriole B. Maintains GFR over a wide range of blood pressures C. Depends on changes in the efferent arteriole D. All of the above E. A and C only ```

Answer 44

D