The kidneys

Question 1

How does blood enter the kidneys?

Answer 1

Through the renal artery

Question 2

What is ultrafiltration?

Answer 2

The filtering of substances out of the blood when the blood passes through the capillaries in the cortex

Question 3

What substances are reabsorbed into the blood?

Answer 3

Useful substances

Glucose and the right amount of water

Question 4

What is selective reabsorption?

Answer 4

The reabsorption of useful substances

Question 5

After selective reabsorption, where do the unwanted substances go to?

Answer 5

They pass through the bladder and are excreted as urine

Question 6

What are nephrons?

Answer 6

Long tubules alone with the bundles of capillaries where the blood is filtered

Question 7

Roughly how many nephrons are there in each kidney?

Answer 7

One million

Question 8

What do the smaller arterioles which go into the cortex of the kidney split into?

Answer 8

Glomerulus

Question 9

What are Glomerulus?

Answer 9

A bundle of capillaries looped inside a hollow ball called a Bowman’s capsule

Question 10

Where does ultrafiltration take place?

Answer 10

In the Bowman’s capsule

Question 11

What is the arteriole that takes blood into each glomerulus called?

Answer 11

Afferent arteriole

Question 12

What is the arteriole that takes filtered blood away from each glomerulus?

Answer 12

Efferent arteriole

Question 13

Which arteriole is smaller in diameter? What is the effect of this?

Answer 13

Efferent arteriole

The blood in the glomerulus is under high pressure

Question 14

What is the effect of the high pressure?

Answer 14

Forces liquid and small molecules in the blood out of the capillary and into the Bowman’s capsule

Question 15

What three layers does the liquid and the small molecules pass through to get into the bowman’s capsule and the nephron tubules?

Answer 15

the capillary endothelium
a membrane
the epithelium of the Bowman’s capsule

Question 16

What molecules cant pass through the three layers?

Answer 16

Large molecules such as proteins and blood cells

Question 17

What is the glomerular filtrate?

Answer 17

The substances that enter the Bowman’s capsule

Question 18

Where does selective reabsorption take place?

Answer 18

As the glomerular filtrate flows along the proximal convoluted tubule (PCT), through the loop of Henle and along the distal convoluted tubule

Question 19

Where do useful substances that leave the nephrons go?

Answer 19

Into the capillary network wrapped around them

Question 20

What does the epithelium of the wall of the PCT have?

Answer 20

Microvilli to increase the surface area for the reabsorption of useful materials from the glomerular filtrate into the blood

Question 21

How are useful substances reabsorbed?

Answer 21

Through active transport and facilitated diffusion

Question 22

How does water enter the blood? How does this happen?

Answer 22

Osmosis

The water potential of the blood is lower than that of the filtrate

Question 23

Where is water reabsorbed?

Answer 23

PCT
loop of Henle
DCT
Collecting duct

Question 24

What is urine usually made up of?

Answer 24

Water
Dissolved salts
Urea
Hormones 
Excess vitamins

Question 25

Where does urine pass along and to?

Answer 25

Ureter to the bladder