Topic 7- Homeotasis, diabetes, themoregulation,

Question 1

Explain how the body uses insulin to regulate high blood glucose concentration

Answer 1

Insulin is secreted by the pancreas. The glucose moves from the blood into the liver where the insulin makes the glucose turn into glycogen and is stored.

Question 2

Explain how the body uses insulin to regulate low blood glucose concentration

Answer 2

Glucagon is secreted by the pancreas which makes the liver turn glycogen into glucose. The glucose is released by the liver into the blood.

Question 3

Describe type 1 diabetes

Answer 3

When the pancreas secretes too little or no insulin so there blood glucose level can rise to a level that can kill them

Question 4

Explain how type 1 diabetes can be treated

Answer 4

With insulin therapy- injecting insulin into the blood usually after a meal so the glucose can be removed quickly from the blood.

They must also limit their intake of foods with lots of simple sugars and exercise regularly

Question 5

Describe type 2 diabetes

Answer 5

When a person becomes resistant to insulin. There is a correlation between obesity and type2.

Question 6

Give the formula for BMI

Answer 6

BMI= weight (kg) / (height (m))2

Question 7

At what BMI are people classified as obese?

Answer 7

30

Question 8

Give the formula for waist-to-hip ratio

Answer 8

Waist circumference (cm) / hip circumference (cm)

Question 9

Storage of a lot of fat is associated with risk of diabetes type 2 in what area of the body?

Answer 9

Abdomen (tummy area)

Question 10

How can type 2 diabetes be controlled?

Answer 10

Healthy diet, regular exercise and losing weight.

Question 11

At what temperature do enzymes in the body work best at?

Answer 11

37c

Question 12

Describe 3 ways your body cools down

Answer 12

1) Erector muscles relax so hairs lie flat
2) Lots of sweat is produced in sweat glands in the dermis. The sweat is released onto the surface of the skin through pores in the epidermis. When the sweat evaporates it transfers energy from your skin to the environment, cooling you down.
3) Blood vessels close to the skin dilate- vasodilation. It allows more blood to flow near the skins surface so it can transfer more energy to the surroundings

Question 13

Describe 3 ways your body warms you up

Answer 13

1) Erector muscles contract so the hairs stand, trapping an insulating layer of air near the surface of the skin which keeps you warm.
2) Little sweat is produced
3) Blood vessels near the skins surface constrict, so less blood flows near the surface of the skin and less energy is transferred to the surroundings.
4) When you’re cold you shiver (your muscles contract automatically) increasing your rate of respiration which transfers more energy and keeps the body warm.

Question 14

What happens if the concentration of water in the blood is too high or too low?

Answer 14

If it is too high, water may move from the blood and into body cells by osmosis. If too much water enters the cells, they may burst.

If its too low, water will move out of the cells into the blood by osmosis, shrinking the cells.

Question 15

What organ helps regulate water content and how?

Answer 15

The kidneys control how much water is reabsorbed and how much is lost in urine.

Question 16

What are the three main roles of the kidney?

Answer 16

1) Removal of urea from the blood. Urea is made in the liver from the breakdown of amino acids
2) Adjustment of ion levels in the blood
3) Adjustment of water levels in the blood

Question 17

What are nephrons?

Answer 17

Nephrons are filtration units in the kidneys

Question 18

What happens at each nephron?

Answer 18

1) The liquid part of the blood (containing water, urea, ions and glucose) is forced out of the glomerulus at high pressure. Bigger molecules and blood cells cant pass through the membrane.

2) As the liquid flows along the nephron, useful substances are reabsorbed:
- All the glucose is absorbed against the concentration gradient
- Sufficient ions are reabsorbed
- Sufficient water is reabsorbed according to the level of ADH.

3) Whatever isn’t reabsorbed (urea, excess water or ions) continues out of the nephron via the collecting duct. It then passes out of the ureter and down the bladder as urine which is released through the urethra.

Question 19

What adaptation of their nephrons do animals living in drought conditions have?

Answer 19

They have longer loops of Henle to reabsorb more water.

Question 20

How is water content controlled by a negative feedback system?

Answer 20

The amount of water reabsorbed is controlled by ADH. The brain monitors water content of the blood and tells the pituitary gland to release ADH according to how much is needed. It makes the collecting ducts more permeable so more water is reabsorbed, stopping the body from becoming dehydrated.

Question 21

How does dialysis filter the blood mechanically?

Answer 21

Patients who have kidney failure cant filter their blood properly. Dialysis has to be done regularly to keep dissolved substances at the right concentration and to remove waste. Dialysis fluid has the same concentration of salts and glucose as blood plasma. The barrier is permeable to tings like ions and waste substances but not big molecules. Excess water/ions move into dialysis fluid. Cells and proteins stay in blood.

Question 22

What precautions can be taken to prevent the body rejecting kidney transplants?

Answer 22

1) A donor with a tissue type that closely matches the patient chosen
2) The patient is treated with drugs that supress the immune system so it wont attack the kidney.