Urinary System

Question 1

What ions are excreted more in the urine if the blood pH becomes alkaline?

Answer 1

HCO3 (bicarbonate).

Question 2

What is the main function of ADH hormone?

Answer 2

To act on the DCT and collecting ducts and increase water reabsorption.

Question 3

Where does the filtration of blood occur in the nephron?

Answer 3

The renal corpuscle.

Question 4

What is the main buffer that controls the acid/base balance present in plasma?

Answer 4

Bicarbonate (HCO3)

Question 5

What is the function of aldosterone?

Answer 5

Aldosterone acts on the kidney tubules and increases the Na+ ions reabsorption.

Question 6

What is the main function of renin?

Answer 6

It converts the plasma protein angiotensinogen to angiotensin I.

Question 7

How does the angiotensin II help in increasing blood pressure in the glomerulus?

Answer 7

Angiotensin II is a vasoconstrictor and causes the constriction of efferent arteriole (outgoing), thereby increasing blood pressure in the glomerulus. It also stimulates the adrenal gland to produce aldosterone which causes water and sodium retention in the tubules, increasing blood volume.

Question 8

What is cystitis?

Answer 8

Inflammation of the urinary bladder.

Question 9

What are diuretics and how do they work (mechanism of action)?

Answer 9

Drugs that increase the rate of urine production. Some inhibit the release of ADH from the Pituitary gland. Some inhibit reabsorption of Na+ ions in the kidney tubules.

Question 10

What is the glomerulus?

Answer 10

It is a network of capillaries interposed in the course of an arteriole (between the afferent and the efferent arteriole).

Question 11

List four main functions of the kidneys.

Answer 11

Maintenance of acid/base balance of the body.
Regulation of water and electrolyte contents of the body.
Reabsorption of useful substances like glucose and other amino acids.
Excretion of waste products like urea, uric acid, and other toxic substances.

Question 12

What is the response of the kidneys in the case of metabolic acidosis?

Answer 12

The kidneys increase the excretion of H+ ions in the urine thereby excreting acidic urine.

Question 13

What conditions stimulate the JG cells to releases the renin enzyme?

Answer 13

Low blood pressure and low sodium ions.

Question 14

What are the two ways the body tries to auto-regulate the GFR?

Answer 14

By stimulating the autonomic nervous system.
By stimulating the JG cells.

Question 15

The cells of which part of the nephron are highly sensitive to ADH?

Answer 15

The distal convoluted tubule (DCT).

Question 16

What are the most reliable clinical tests used to estimate the glomerular filtration rate (GFR)?

Answer 16

BUN and creatinine in the blood.

Question 17

Name the disease that occurs due to deficiency of ADH.

Answer 17

Diabetes insipidus.

Question 18

Which part of the nephron contains the most concentrated fluid?

Answer 18

The Loop of Henle.

Question 19

What cells in the kidneys release renin?

Answer 19

Juxta-glomerular cells (JG cells).

Question 20

Which part of the nephron absorbs most of the substances of the glomerular filtrate?

Answer 20

The proximal convoluted tubule (PCT).

Question 21

What is the effect of increased osmolarity (blood osmotic pressure) on filtration?

Answer 21

A decrease in glomerular filtration.

Question 22

What is pyelonephritis?

Answer 22

Inflammation of the nephrons and renal pelvis.

Question 23

Define tubular maximum.

Answer 23

The maximum capability of the kidney tubules to reabsorb substances.

Question 24

What is the response of the kidneys in the case of metabolic alkalosis?

Answer 24

The kidneys would increase the excretion of bicarbonate (HCO3) ions, thereby excreting alkaline urine.

Question 25

What ions are excreted more in urine if the blood pH becomes acidic?

Answer 25

H+ ions.

Question 26

What events are taking place the descending limb of the loop of henle when filtrate is passion through it?

Answer 26

Here the cells are permeable to water; therefore, water starts moving out of the tubular lumen into medullary interstitial tissue. These cells are impermeable to Na+ and Cl- ions which stay in the tubular lumen with the filtrate moving towards the bottom of the loop, making the urine most concentrated here.

Question 27

What is the effect of increased blood pressure in the glomerulus on filtration?

Answer 27

An increase in glomerular filtration.

Question 28

What events are taking place in the ascending limb of the Loop of Henle when filtrate is passing through it?

Answer 28

The cells in the ascending limb area impermeable to water and don't allow the water to move in or out. But they are very permeable to sodium ions (solutes) and Na+ ions move out of the tubule into medullary interstitial tissue.

Question 29

What would happen if the concentration of glucose increases more than its tubular maximum?

Answer 29

Glycosuria (glucose in the urine).

Question 30

The quantity of glomerular filtrate produced depends on what three factors?

Answer 30

Blood pressure in the glomerulus. Osmotic pressure in the glomerulus. Hydrostatic pressure in the glomerular capsule.