B3.3

Question 1

What 3 things are found in urine?

Answer 1

~ Urea
~ Excess water
~ Excess mineral ions

Question 2

What produces urea and where?

Answer 2

Excess amino acids are converted into urea in the liver

Question 3

Where is urea transported to?

Answer 3

From the liver to the kidney via the blood, then stored in the bladder as urine

Question 4

Why aren’t protein molecules or red blood cells filtered into the kidney tubule?

Answer 4

They’re too big to fit through the partially permeable membrane

Question 5

What happens in the kidneys?

Answer 5

~ Blood is filtered into kidney tubule
~ All glucose is reabsorbed
~ ions and water needed by the body are reabsorbed
~ Remaining excess ions, excess water and urea are taken to the bladder as urine

Question 6

What main 3 things do the kidneys do?

Answer 6

~ Control water levels
~ Remove toxic waste
~ Adjust salt levels

Question 7

What happens if the kidneys don’t work?

Answer 7

Urea and excess ions build up in the body, which can cause illness and death

Question 8

Why does the dialysis fluid have the same concentration of glucose as the blood?

Answer 8

As this ensures that there will be no diffusion because the blood wants to keep all the glucose it has

Question 9

Why does the dialysis fluid contain a certain amount of ion concentration?

Answer 9

So that anything that is higher than this in the blood is diffused out

Question 10

Why is the dialysis fluid always flowing?

Answer 10

To ensure that there is always a low concentration of urea

Question 11

Why can the body sometimes reject kidney transplants?

Answer 11

Kidneys from other bodies have different tissue types, so the cells have antigens which the body doesn’t recognise and produces antibodies against them

Question 12

What are advantages of dialysis?

Answer 12

~ More available than kidney donors

~ No drugs needed

Question 13

What are disadvantages of dialysis?

Answer 13

~ Regular, long sessions

~ Less freedom (can’t go on holidays)

Question 14

What are disadvantages of kidney transplants?

Answer 14

~ Difficult to find a suitable donor
~ Body may reject kidney
~ Need drugs

Question 15

What are advantages of kidney transplants?

Answer 15

~ Cheaper than dialysis

~ Freedom

Question 16

What can happen to cells if the water or ion content of the body is wrong?

Answer 16

The cells will be damaged because osmosis will causes them to shrivel or explode

Question 17

What does the thermoregulatory centre in the brain do?

Answer 17

~ Has temperature receptors in the brain that detect the temperature of blood in it
~ Has receptors on the skin that send impulses through nerve cells to the thermoregulatory centre which allows it to control temperatures in the body

Question 18

What happens when you wear shorts in cold weather?

Answer 18

~ Body temperature drops
~ Triggers shivering
~ Produces heat

Question 19

Why does consuming a cold drink warm you up?

Answer 19

~ Brain temperature decreases, this causes it to stop the body from sweating
~ The lack of sweating causes the skin temperature to increase

Question 20

What does the pancreas do?

Answer 20

~ Monitors blood sugar levels
~ Produces insulin in ribosomes if blood sugar is too high, and this allows glucose to enter cells
~ Converts glucose to glycogen

Question 21

What is type 1 diabetes caused by?

Answer 21

Pancreas not producing enough insulin, and this causes the glucose concentration to rise to a high level

Question 22

What are symptoms of type 1 diabetes?

Answer 22

~ High blood sugar / inability to control blood sugar
~ Frequent urination
~ Thirst

Question 23

What can cause blood sugar to decrease?

Answer 23

~ Overdose of insulin

~ Not eating or drinking for a while

Question 24

How do diabetics control their diet?

Answer 24

~ Have small regular meals

~ Have low sugar and carbs

Question 25

Why is insulin injected and not consumed orally?

Answer 25

~ So it goes straight in the blood

~ It’s a protein so if consumed would be broken down in the stomach

Question 26

Why does sweating cool the body?

Answer 26

~ Water in the sweat evaporates and carries heat energy away

~ This cools the skin and body

Question 27

Why does a person look red when they’re hot?

Answer 27

Their blood flows closer to the skin to increase heat lost by radiation

Question 28

What happens to blood vessels when the body’s too hot?

Answer 28

Blood vessels supplying the skin capillaries dilate so more blood flows through the capillaries, therefore more heat is lost by radiation

Question 29

What happens to blood vessels when the body’s too cold?

Answer 29

Blood vessels supplying the skin capillaries constrict so less blood flows through the capillaries, therefore less heat is lost by radiation

Question 30

Why does shivering warm you up?

Answer 30

The contraction of the muscles requires energy, so some heat energy is required

Question 31

What does insulin do as well as keeping blood sugar levels down?

Answer 31

~ Allows glucose in blood to enter cells and get out of the blood
~ Converts glucose to glycogen which is a way of storing the glucose out of the blood, usually in the liver or muscles

Question 32

What does the hormone glucagon do?

Answer 32

It’s released from the pancreas and converts glycogen back to glucose (in the liver)

Question 33

Why does the body cool down by sweating?

Answer 33

As water in the sweat evaporates from skin it carries heat energy away from the skin which cools it and reduces the overall body temperature

Question 34

What process releases glucose needed to provide energy for the body?

Answer 34

Respiration

Question 35

What are symptoms of low blood sugar?

Answer 35

~ Weakness

~ Dizziness

Question 36

What are symptoms of high blood sugar?

Answer 36

~ Thirst

~ Need to urinate