5. Homeostasis and Response (diabetes and the kidneys)

Question 1

What is type 1 diabetes?

Answer 1

• An autoimmune disorder in which the pancreas does not produce sufficient insulin to control the blood glucose concentration
• As a result blood glucose levels are often very high

Question 2

How can type 1 diabetes be treated?

Answer 2

• Insulin injections before meals - allows glucose to be converted into glycogen
• Limiting carbohydrate intake
• Pancreas and pancreatic cell transplants
• genetic engineering of pancreatic cells

Question 3

What is type 2 diabetes?

Answer 3

A disorder in which the body’s cells stop responding to insulin, leading to an uncontrolled blood glucose concentration

Question 4

What two things are possible triggers for type 2 diabetes?

Answer 4

increasing age and obesity

Question 5

How can type 2 diabetes be treated?

Answer 5

• following a carefully-controlled diet
• doing regular exercise
• losing weight
• use of drugs which increase insulin production and effectiveness

Question 6

What is osmosis?

Answer 6

The net movement of water particles from an area of high concentration to an area of low concentration, across a partially permeable membrane

Question 7

What can very high levels of blood glucose concentration lead to?

Answer 7

excessive urination, tiredness and weight loss

Question 8

In what ways is water lost from the body?

Answer 8

• during exhalation via the lungs
• sweating
• urine (some reabsorbed in the kidney)

Question 9

What is deamination?

Answer 9

When excess amigo acids are converted into lipids or carbohydrates, which can be stored as an energy source for later. This process also produces urea, which has to be excreted by the kidneys

Question 10

Where does deamination take place?

Answer 10

in the liver

Question 11

What are the functions of the kidneys?

Answer 11

• remove urea
• regulate ion levels
• regulate water levels

Question 12

In what ways are ions lost from the body?

Answer 12

• sweating
• urine (some reabsorbed in the kidney)

Question 13

How are excess amino acids excreted from the body?

Answer 13

• excess amino acids are deaminated in the liver to form ammonia
• ammonia is toxic, therefore it is converted into urea
• urea is excreted from the body via sweat and urine

Question 14

How do the kidneys maintain the balance of water and other substances in the body?

Answer 14

• filter blood in order to remove waste products eg. urea
• selectively reabsorb useful molecules eg. glucose, water, ions

Question 15

What is the full name of the hormone ADH?

Answer 15

Anti-diuretic hormone

Question 16

Where is ADH secreted in the body?

Answer 16

the pituitary gland of the brain

Question 17

How does ADH affect the reabsorption of water in the kidneys?

Answer 17

• when the blood is too concentrated, the pituitary gland secretes more ADH
• ADH travels in the bloodstream to the kidney and increases the permeability of kidney tubules to water
• more water is reabsorbed in the kidneys, resulting in a smaller volume of more concentrated urine

Question 18

Why is kidney failure dangerous?

Answer 18

When the kidneys are damaged, they may be unable to filter the blood properly. this may lead to:
- a build-up of toxic molecules (eg.urea) in the body
- an uncontrolled ion and water balance and cells being damaged as a result of osmosis

Question 19

What are the two main ways of treating kidney failure?

Answer 19

• dialysis
• transplant

Question 20

What is kidney dialysis?

Answer 20

The use of a specialist machine to carry out the function of the kidneys.

Question 21

How does kidney dialysis work?

Answer 21

dialysis fluid contains the same concentration of glucose and ions as healthy blood. As a result, only excess and waste molecules are lost from the blood, and glucose and ions remain

Question 22

What is genetic engineering?

Answer 22

changing a cell’s DNA so that it performs a desired function

Question 23

If there is too much water in the body, what could happen to our cells?

Answer 23

• the water could enter our cells by osmosis
• causing them to swell up and possibly even burst

Question 24

Which part of the brain detects the level of water in the body?

Answer 24

hypothalamus

Question 25

What is selective reabsorption in the kidneys?

Answer 25

As the filtrate passes through the kidneys, useful substances like glucose are reabsorbed from the tubules into the blood

Question 26

What is filtration or (ultrafiltration) in the kidneys?

Answer 26

as blood passes through the kidneys, small substances like glucose, amino acids, and water are absorbed from the blood into the kidneys