1.11.Homeostasis

Question 1

What is the internal environment?

Answer 1

The conditions inside the body.

Question 2

Why must temperature be kept constant?

Answer 2

So that enzymes that help reactions to occur work quickly.

Question 3

Why must the internal environment have enough water and what happens if there is too much water.

Answer 3

Water is needed for substances to dissolve and for chemical reactions to take place within the cell.
Too much water can cause swellings and high blood pressure.

Question 4

What is osmoregulation?

Answer 4

The control of water in the body.

Question 5

In what ways does the body loose water?

Answer 5

1. Through sweat- produced by sweat glands which makes substances and releases chemicals
2. Urine- too much water=kidneys release more urine. Not enough water=kidneys release less urine +brain makes you thirsty.
3. Breath

Question 6

Why is blood glucose regulation important?

Answer 6

If glucose concentration gets too high or too low, one can become very ill.

Question 7

What is thermoregulation?

Answer 7

The control of body temperature.

Question 8

Why does the body maintain a temp of 37*C ?

Answer 8

Many chemical reactions work best at this temperature.

Question 9

What is the hypothalamus and what does it do?

Answer 9

Small part of the brain that constantly monitors temperature.

It receives information from nerve endings in the dermis of skin about temperature outside of the body.

Receives information about temperature from blood inside the body.

Question 10

What is homeostasis?

Answer 10

Keeping the internal environment stable.

Question 11

What does the hypothalamus do when body temperature goes beneath 37*C?

Answer 11

1. Causes muscles to shiver
2. Causes erector muscles in dermis to contract ( body hairs stand up straight and traps air as insulation)
   (Oil released from the sebaceous glands keeps the skin lubricated and good condition)
3. Reduced blood flow near the the skin. (Warm blood is kept deep, less heat loss to air)

Question 12

What does the hypothalamus do when the temperature gets over 37*C ?

Answer 12

1. Sweat gland secretes sweat- cools the skin when evaporated.
2. Blood flow near skin increases so heat is lost to surrounding air.
3. Erector vessels relax so that hair lies flat.

Question 13

What is vasoconstriction and vasodilation?

Answer 13

Vasoconstriction- when it’s cold the hypothalamus reduces blood flow to the skin by narrowing the blood vessels closet surface.

Vasodilation- when the body gets too hot The hypothalamus increases blood flow by widening the vessels closets to the surface

Question 14

What is negative feedback?

Answer 14

Control of body temperature- when a change happens in environment body works to make it the opposite direction too keep homeostasis in the body under control