TB- lqc 7

Question 1

describe what happens in the primary infection with TB and how bacteria evade the immune system

Answer 1

The M.tuberculosis causes an inflammatory response and macrophages engulf the bacteria. The bacteria have thick waxy cell walls and so are able to resist digestion by the macrophage. The bacteria lie dormant in macrophages and a mass of tissue known as a granuloma forms. The granuloma, also known as a tubercle, is anaerobic and contains dormant bacteria and macrophages. As the macrophages are unable to present antigen the immune system is suppressed. The person has no signs or symptoms of the disease and are said to have latent TB.

Question 2

describe what happens in the secondary phase of TB (active TB)

Answer 2

The bacteria multiply rapidly and destroy the lung tissue, creating holes or cavities. The bacteria are able to leave the tubercles and potentially spread around the body.

Question 3

why does the secondary phase of TB take place

Answer 3

When the patient’s immune system is weakened. This could be due to age (very young or very old), malnutrition, poor living conditions, other infections e.g. HIV

Question 4

what are the symptoms of active TB?

Answer 4

Coughing (sometimes with blood), shortness of breath, loss of appetite, weight loss, fever, extreme fatigue.

Question 5

what happens in glandular TB?

Answer 5

The bacteria move to infect other parts of the body e.g. blood, lymph nodes and central nervous system. Lymph nodes in the neck or armpits can enlarge

Question 6

state the ways that TB can be diagnosed

Answer 6

Skin (injecting a small amount of tuberculin) and blood tests, identification of bacteria in sputum, chest X-rays to identify tubercles