2.9.4 Kidney Structure & Function

Question 1

Where are kidneys located

Answer 1

in the back of the abdomen

Question 2

What are the kidneys two important functions in the body

Answer 2

1. They regulate the water content of the blood (vital for maintaining blood pressure)

Question 3

Name the 7 waste substances that need to removed from the blood

Answer 3

#1. Urea
#2. Creatinine 
#3. Ammonia
#4. Excess Hormones
#5. Excess Water
#6. Uric Acid
#7. Excess Salt/Ions

Question 4

There are three regions of the kidney, what are they?

Answer 4

1. Cortex – the outermost region

Question 5

Each kidney contains around a million tiny structures called, what?

Answer 5

nephrons, also known as kidney tubules or renal tubules

Question 6

Where are Nephrons located

Answer 6

Nephrons start in the cortex of the kidney, loop down into the medulla and back up to the cortex

Question 7

The contents of the nephrons drain into the, what?

Answer 7

the renal pelvis and the urine collects there before it flows into the ureter to be carried to the bladder for storage

Question 8

The nephron is made up of a kidney tubule which has several sections, what are they?

Answer 8

1. Bowman’s capsule

Question 9

What surrounds the tubule

Answer 9

a network of capillaries with a knotted section which sits inside the Bowman’s capsule

Question 10

In the kidney, before the key substances are reabsorbed back into the blood, what happens

Answer 10

blood is filtered (ultrafiltration)

Question 11

Explain the process of ultrafiltration

Answer 11

1. Arterioles branch off the renal artery and lead to each nephron, where they form a knot of capillaries (the glomerulus) sitting inside the cup-shaped Bowman’s capsule

Question 12

(Components of Filtrate Table) Where is water reabsorbed at?

Answer 12

Loop of henle and collecting duct

Question 13

(Components of Filtrate Table) Where is Salts reabsorbed at

Answer 13

Loop of henle

Question 14

(Components of Filtrate Table) Where is Glucose reabsorbed at?

Answer 14

Proxminal convoluted tubule

Question 15

(Components of Filtrate Table) Where is Urea reabsorbed at?

Answer 15

Not Reabsorbed

Question 16

After the glomerular filtrate enters the Bowman’s Capsule, glucose is the first substance to be reabsorbed, where?

Answer 16

at the proximal (first) convoluted tubule

• This takes place by active transport

Question 17

The nephron is adapted for this by having many mitochondria to provide energy for, what?

Answer 17

the active transport of glucose molecules

Question 18

Reabsorption of glucose cannot take place anywhere else in the nephron, why?

Answer 18

the gates that facilitate the active transport of glucose are only found in the proximal convoluted tubule

Question 19

In a person with a normal blood glucose level, there are enough gates present to remove, what?

Answer 19

all of the glucose from the filtrate back into the blood

Question 20

People with diabetes cannot control their blood glucose levels and they are often very high, what does that mean?

Answer 20

that not all of the glucose filtered out can be reabsorbed into the blood in the proximal convoluted tubule

• As there is nowhere else for the glucose to be reabsorbed, it continues in the filtrate and ends up in the urine

Question 21

What is one of the first tests a doctor may do to check is someone is diabetic

Answer 21

to test their urine for the presence of glucose

Question 22

As the filtrate drips through the Loop of Henle necessary salts are reabsorbed back into the blood by, what?

Answer 22

diffusion

Question 23

As salts are reabsorbed back into the blood, water follows by, what?

Answer 23

osmosis

Question 24

How is water also reabsorbed

Answer 24

from the collecting duct in different amounts depending on how much water the body needs at that time

Question 25

Exam Tip

Answer 25

Take care to describe clearly where substances are moving from and to in the kidneys (ie. glucose moves from the filtrate into the bloodstream when it is selectively reabsorbed. Using your technical terminology incorrectly here could lose you marks.

Also – small substances such as urea are forced out of the blood during filtration as a result of high-pressure mass flow, they don’t diffuse out of the blood.