13. Excretion

Question 1

In which order does Urea pass through structures in the body?

Answer 1

Liver –> Kidney –> Ureter –> Urethra

Question 2

In which order does Urea pass through structures in the body? (From where it is produced and removed from the blood)

Answer 2

Liver –> Heart –> Lungs –> Heart –> Kidneys

Question 3

Explain the importance of microvilli.

Answer 3

• Increases SA
• This will lead to more reabsorption of glucose

Question 4

Why does the renal artery have blood in the highest pressure?

Answer 4

• Has a thick wall for ultrafiltration

Question 5

Outline how kidney tubules function to produce urine from the substances in blood plasma

Answer 5

• No protein in the Bowmans capsule
• All glucose, salts, and urea are filtered out of the glomerulus
• All glucose reabsorbed in loop of henle
• Reabsorption of some salts by loop of henle
• Urea concentration is higher in loop of henle
• Active transport of glucose from tubule back into blood

Question 6

Describe how and where urea is formed in the body.

Answer 6

• Breakdown of excess amino acids by DEAMINATION
• Urea is formed in the liver

Question 7

Suggest why there is a difference in the volume of urine produced before running compared with after.

Answer 7

• Lost more water while running by sweating more
• Reduced intake of water while running

Question 8

Describe how the kidney tubules enable the excretion of salts.

Answer 8

• Salts move from the blood into the tubule
• Small molecules are filtered
• There is some salt reabsorption, therefore, excess salt remains in the urine.

Question 9

Explain why urine tests are a good indicator of how much salt has been consumed.

Answer 9

• Excess salt is excreted
• Some salt is reabsorbed in the blood
• But, people are not reliable in measuring how much salt they eat.

Question 10

Role of the glomerulus?

Answer 10

• Provides blood at high pressure
• Provides large SA

Question 11

Describe the structure of the glomerulus.

Answer 11

• Capillaries are one-cell thick
• Network of capillaries is tangled

Question 12

Advantages of having kidney transplant instead of dialysis

Answer 12

• Cost-effective in the long-term
• A working kidney is long-lasting
• No need for a restricted diet.

Question 13

Describe how urea is transported in the blood to the kidney

Answer 13

• Dissolved in solution

Question 14

Describe the process of filtration in the kidney

Answer 14

• Small molecules forced out of blood
• Examples include: Urea, and glucose