The Kidneys And The Excretory System - Part 3 (T2)

Question 1

Name the six main areas of the nephron…

Answer 1

• bowman’s capsule - glomerulus
• collecting duct
• blood capillaries
• convoluted tubules
• loop of henle

Question 2

Summarise the process of the nephron in three points…

Answer 2

• filtration: lots of water, ions, urea and sugar are squeezed from the blood into the tubules
• selective reabsorption: ions and sugars are reabsorbed back into the blood from the tubules and the amount of water in the blood is regulated at a constant rate
• excretion of waste: urea, excess water and ions travel to the bladder as urine

Question 3

What is osmoregulation?

Answer 3

It is the regulation of water in the blood in the kidneys, keeping it at a constant rate

Question 4

What hormone controls the kidneys and the concentration of urine within them?

Answer 4

• ADH (anti-diuretic hormone)
• this is produced by the pituitary gland

Question 5

If water concentration in the kidneys falls, what happens?

Answer 5

• more ADH is produced
• the kidney absorbs more water
• a small volume of very concentrated urine is produced, reducing water loss

Question 6

If water concentration in the kidneys rises, what happens?

Answer 6

• less ADH is produced
• the kidney absorbs less water
• a large volume of very dilute urine is produced
• this increases water loss

Question 7

What is meant by the term ‘negative feedback mechanism’?

Answer 7

When a substance is produced in our bodies to return a system to normal

Question 8

How is ADH an example of a negative feedback mechanism?

Answer 8

ADH is produced in response to low blood water levels

Question 9

What is the darker outer region of the kidney called?

Answer 9

The cortex

Question 10

What does the cortex contain?

Answer 10

• tiny blood vessels that branch off from the renal artery
• microscopic tubes and filtering units known as kidney tubules or nephrons