Excretion

Question 1

What do the kidneys excrete?

Answer 1

Nitrogenous wastes; Ammonia, urea, uric acid, creatinine

Question 2

——–O——-
H2N -C- NH2

Answer 2

Urea; Water soluble, excreted in urine

Question 3

What is urea composed of?

Answer 3

3% Urea, 2% Salts, 95% Water

Question 4

What gives urine its yellow colour?

Answer 4

urochrome from breakdown of heme

Question 5

Renal vein

Answer 5

Carries blood from kidenys back to heart

Question 6

Renal artery

Answer 6

Carries blood to kidenys

Question 7

Kidenys three major divisions?

Answer 7

Cortex (outer layer), Medulla (middle layer), and Pelvis (inner cavity)

Question 8

Bowmans capsule

Answer 8

Where wastes are forced out of the blood and into the nephron and enters the glomerulus

Question 9

Afferent artiriole vs Efferent artiriole

Answer 9

Carries blood to glomerulus
Carries blood from glomerulus

Question 10

Urine formation (3)

Answer 10

1. Pressure filtration
2. Selective re-absorbtion
   3.Tubular excretion

Question 11

What can and cannot pass through the glomerulus?

Answer 11

Can: (Small molecules)
H2O, nitrogenous wastes, nutrients, ions (salts)

Cannot: (Large molecules)
Blood cells, platelets, protein

Question 12

What is filtrate?

Answer 12

The small molecules that were forced into the Bowmans capsule.

Question 13

Function of the Juxtoglomelar apparatis?

Answer 13

To achieve high pressures for filtration. If needed will release Renin hormone to increase blood pressure

Question 14

What gets reabsorbed after pressure filtration?

Answer 14

H2O, nutrients, salts (Na+, Cl-)

Question 15

What does not get reabsorbed?

Answer 15

Some H2O, wastes, excess salts do not get reabsorbed and continue through the loop of Henle

Question 16

What is active transport?

Answer 16

Requires ATP and a carrier molecule (glucose, Na+)

Question 17

What is passive transport?

Answer 17

e.g Cl-, H2O

Question 18

What is the primary role of the loop of Henle?

Answer 18

Reabsorption of H2O

Question 19

Why is the urine hypertonic to plasma?

Answer 19

Na+ Cl- is also passively and actively reabsorbed concentrating the urine

Question 20

What is tubular excretion?

Answer 20

Process where other non filterable wastes can be added to tubular fluid and excreted in urine

Question 21

Where and what is excreted in tubular excretion?

Answer 21

An active process, occurs in the DCT (distal convuluted tubule)
Substances include: Penicillan, H+, NH3

Question 22

Explain the hormone renin.

Answer 22

Renin is released by the Juxtoglomelur apparatis to achieve high pressures for filtration. It increases blood pressure. People with kidney disease have high blood pressure from the constant release of renin.

Question 23

What is the function of ADH?

Answer 23

Promotes reabsorption if low H2O content of blood. Decreases the urine volume by diluting it to increase blood volume

Question 24

What does aldesterone do?

Answer 24

Released by the adrenal cortex, makes the kidneys retain more Na+ and excrete K+

Question 25

Hypertension

Answer 25

Na+ in the blood is too high

Question 26

Hypotension

Answer 26

Na+ in the blood is too low, results in not enough H2O reabsorbed

Question 27

What if the blood is more acidic?

Answer 27

More H+ and ammonia is excreted, more sodium bicarbonate is reabsorbed which neutralizes acid

Question 28

What if blood is more alkaline?

Answer 28

Less H+ excreted, less Na+ and HCO3- reabsorbed