7.1

Question 0

It is important that what 3 factors of blood and tissue fluid are maintained:

Answer 0

• composition
• pH
• volume

Question 1

Homeostasis is the

Answer 1

Regulation of the body’s internal environment

Question 2

Several reasons for the maintenance of blood and tissue fluid composition, pH and volume:

Answer 2

• enzymes that control the metabolic pathways

- cells

Question 3

Affect on enzymes that control metabolic pathways within cells work most efficiently at their optimum temperature and pH. If conditions vary significantly from optimum then they start to

Answer 3

Denature

Question 4

Effect on cells: if water potential of the blood and tissue fluid changes significantly, body cells may take in water by osmosis, causing them to

Or they could lose water by osmosis, stopping them from:

Answer 4

Swell or burst

Working efficiently

Question 5

Homeostasis needs a control system that detects stimuli and makes the necessary changes to bring the internal environment back to

Answer 5

Normal

Question 6

Negative feedback is a series of changes, important in homeostasis that result in the body’s internal environment being:

Answer 6

Restored to its normal level

Question 7

The body detects the change in the body’s internal environment. Hormones and/or nerve impulses are used to bring about a

Answer 7

Corrective mechanism that returns conditions to the normal level (negative feedback)

Question 8

Example of negative feedback:

Answer 8

Respiratory and circulatory system

Question 9

Chemoreceptors in the carotid bodies, the aortic bodies and the medulla of the brain monitor blood pH. Blood containing more carbon dioxide is slightly acidic causing blood pH to

Answer 9

Fall.

Question 10

The fall in blood pH is detected by chemoreceptors which send impulses to the

Answer 10

Cardiovascular and respiratory centres in the medulla of the brain.

Question 11

Respiratory centre in the medulla sends more nerve impulses to the diaphragm and intercostal muscles, causing an increase in the

Answer 11

Rate and depth of breathing

Question 12

The cardiovascular centre sends more nerve impulses along the sympathetic nerve to the Sino-atrial (SAN) of the heart, causing an increase in

Answer 12

Heart rate

Question 13

As a result of these changes the carbon dioxide concentration in the blood

Answer 13

Falls back to the normal level