The causes of disease: pathogens, lifestyle and genes：练习题

In the study of non-communicable diseases such as cancer and coronary heart disease, which of the following best defines a risk factor?

The risk of thrombosis and aneurysm is significantly increased by the presence of an atheroma. Which of the following correctly links an atheroma to a thrombosis?

Disease results when pathogens penetrate the body's interfaces with the environment. Which biological interface is most likely the entry point for a pathogen that primarily results in symptoms of severe abdominal pain and frequent watery stools?

A study compares two groups of people over 20 years. Group X follows a diet high in saturated fats and has a sedentary lifestyle. Group Y follows a balanced diet and exercises regularly. The study finds that Group X has a relative risk of \( 2.5 \) for developing an atheroma. If the incidence in Group Y is \( 4 \) per \( 1000 \), what is the expected incidence in Group X?

Epidemiological studies have identified several risk factors associated with coronary heart disease (CHD). Which combination of factors represents lifestyle choices that significantly increase the risk of developing CHD?

Describe two primary mechanisms by which pathogens, such as bacteria and viruses, cause damage to the host tissues and result in disease symptoms.

Explain why antigen variability in certain pathogens, such as the influenza virus, makes it difficult for the human immune system to provide long-term protection against reinfection.

Explain why the gas-exchange and digestive systems are particularly vulnerable interfaces for the penetration of pathogens into a mammal's body.

Epidemiological studies have identified a strong correlation between cigarette smoking and the incidence of coronary heart disease (CHD).
a) Distinguish between the term 'correlation' and a 'causal relationship' in the context of lifestyle risk factors and disease.
b) List two other specific risk factors, excluding smoking, that are known to increase the probability of a person developing coronary heart disease.

Pathogens frequently enter the mammalian body through interfaces with the environment, such as the gas-exchange system.
a) Explain why the structural adaptations of the gas-exchange surface make it a particularly vulnerable site for the penetration of pathogens.
b) Some pathogenic bacteria produce exotoxins. Explain how these molecules, which are often proteins, can lead to the physiological symptoms of a disease.
c) Contrast the method of cellular damage caused by a virus with that of a bacterium that primarily causes disease via the release of endotoxins.