The causes of disease

Question 1

Pathogens

Answer 1

Microorganisms that cause disease

Question 2

Sites for entry of pathogens

Answer 2

digestive system, respiratory system, reproductive system, (excretory system)

Question 3

Why the digestive and respiratory systems are sites for entry of pathogens?

Answer 3

• exchange of material between internal and external environments
• (diffusion takes place in both)
• thin, moist body linings
• large surface area
• well supplied with blood vessels
• so, it’s easy for pathogens to enter

Question 4

Ways in which pathogens cause disease

Answer 4

• by damaging host tissues
• by producing toxins

Question 5

Cancer - lifestyle choices and risk factors

Answer 5

• smoking
• diet
• obesity
• physical activity
• sunlight

Question 6

Coronary disease - lifestyle choices and risk factors

Answer 6

• smoking
• high blood pressure
• blood cholesterol levels (kept lower by including fewer saturated fatty acids in the diet)
• obesity
• diet (high conc. of salt increase blood pressure, high levels of saturated fatty acids increase blood cholesterol concentration)
• physical activity (aerobic exercise)

Question 7

Reducing risks of cancer and CHD

Answer 7

• giving up smoking
• avoiding becoming overweight
• reducing salt intake in the diet
• reducing intake of cholesterol and saturated fats in the diet
• taking regular aerobic exercise
• reducing alcohol consumption
• increasing the intake of dietary fibre and antioxidants