Ocr A2 Biology - The Kidneys And Excretion

Front 1

Blood is filtered at the start of...

Back 1

...nephrones

Front 2

Label this diagram of a nephron.

Back 2

Front 3

1. Blood from the .......... artery enters smaller .......... in the .......... .

Back 3

1. renal

2. arterioles

3. cortex

Front 4

What is the name of the structure that the arteriole splits into? Describe this structure.

Back 4

• The glomerulus.
  
• A bundle of capillaries looped inside a hollow ball called the Bowman's capsule.
• This is where ultrafiltration takes place.

Front 5

What is the name of the arteriole that takes blood into each glomerulus?

Back 5

The afferent arteriole.

Front 6

What is the name of the arteriole that takes blood out of each glomerulus?

Back 6

The efferent arteriole.

Front 7

The efferent arteriole smaller in diameter than the afferent arteriole, why is this?

Back 7

So the blood in the glomerulus is under high pressure.

Front 8

What does the high pressure in the glomerulus cause?

Back 8

It forces liquids and small particles out of the capillary and into the Bowman's capsule.

Front 9

State and name how many layers the liquid and small molecules have to pass to get into the Bowman's capsule and enter the nephron tubule.

Back 9

• The capillary wall
• The basement membrane
• The epithelium of the Bowman's capsule.

Front 10

What happens to larger molecules under this high pressure?

Back 10

They stay in the blood as they are too large to pass through the membranes.

Front 11

What is the name of the liquids and small substances once it has passed into the nephron tubule?

Back 11

Filtrate.

Front 12

What areas of the nephron does selective reabsorption take place?

Back 12

• Proximal convoluted tubule (PCT)
• The loop of Henle
• Distal convoluted tubule (DCT)

Front 13

Useful substances are ......... by the ......... network that's wrapped around them.

Back 13

1. reabsorbed

2. capillary

Front 14

How is is epithelium of the wall of the PCT specialised for reabsorption?

Back 14

• It has microvilli which provide a large surface area for reabsorption of useful materials from the filtrate into the blood.

Front 15

What substances are reabsorbed at the PCT? Name the two mechanisms they are reabsorbed by.

Back 15

• Glucose, amino acids, vitamins and some salts.
  
• Active transport and facilitated diffusion.

Front 16

How and why does water enter the blood from the filtrate?

Back 16

• The water potential of blood is lower than the water potential of the filtrate, so water transfers over by osmosis.

Front 17

What parts of the nephron is water reabsorbed at?

Back 17

• Loop of Henle
• DCT
• Collecting duct

Front 18

What happens to the filtrate that remains after selective reabsorbtion?

Back 18

It passes along the ureter to the bladder.

Front 19

What is urine made up of?

Back 19

• Water
• Dissolved salts
• Urea
• Other substances such as hormones and excess vitamins.

Front 20

What does urine not usually contain?

Back 20

• Proteins and blood cells - they are too big to be filtered out.
• Glucose, amino acids and vitamins - they are actively reabsorbed into the blood.

Front 21

Label this image of the renal cortex.

Back 21

Front 22

Label this image of a renal medulla

Back 22