4.2 Lung Disease Flashcards
What are the later symptoms of pulmonary tuberculosis?
Fever and coughing up blood
What are the initial symptoms of pulmonary tuberculosis?
a persistent cough, tiredness and loss of appetite that leads to weight loss
What is the name of the bacterium which causes pulmonary tuberculosis?
Mycobacterium tuberculosis or mycobacterium bovis
How is pulmonary tuberculosis spread?
Transmitted though the air by droplets released when an infected person coughs, laughs or speaks
M.tuberculosis can survive for how long after the droplets have dried up?
Several weeks
Pulmonary tuberculosis is usually spread in family and friends rather than casual meetings. It spreads in crowds and poorly ventilated conditions. Which animal can transmit the disease to humans?
Cows
Which people are at greatest risk from pulmonary tuberculosis?
People living and sleeping in overcrowded conditions
People who work or reside in long-term care facilities where lots of people love close together e.g hospitals
People who are from countries where TB is common
People who have reduced immunity
Describe the primary infection of pulmonary tuberculosis. Who does this usually occur in?
- Children
- bacteria grow and divide within the upper regions of the lungs where there is lots of oxygen
- the body’s immune system responds and white blood cells accumulate at the site of infection to ingest the bacteria
- this leads to immflamation and the enlargement of the lymph nodes that drain the area of the lungs.
If a healthy person gets pulmonary tuberculosis what is likely to occur?
There are few symptoms if any and the infection is controlled within a few weeks. However, some bacteria usually remain.
Many years later these bacteria may re-emerge to cause a second infection of TB - post-primary tuberculosis (typically occurs in adults)
This infection also arises in the upper lungs and is not so easy to control. The bacteria destroy the lung tissue resulting in cavities and where the lung repairs itself - scar tissue
The sufferer coughs up damaged lung tissue containing bacteria and blood - TB can spread and be fatal without treatment.
What is the main biological preventive measure for tuberculosis?
Vaccination
What are the social and economic measures that can be introduced to reduce the numbers of TB cases?
Better education about TB
More and better housing
Improved health facilities and treatments
Better nutrition
Which characteristic is shown in people vulnerable to contracting a disease like TB
People with reduced immune systems e.g very young/old, AIDS, transplant surgery individuals
Give three different lung diseases.
Pulmonary fibrosis, asthma and emphysema
What causes pulmonary fibrosis to arise?
When scars form on the epithelium of the lungs causing them to become irreversibly thickened. Therefore oxygen cannot diffuse into the blood as efficiently because the diffusion pathway is significantly longer and the volume of air that can be taken in is reduced. Elasticity is also reduced.
Cause is unclear - evidence suggests it is a reaction to microscopic lung injury - some individuals genetically more susceptible
What are the effects of pulmonary fibrosis?
Shortness of breath
Chronic dry cough - fibrous tissue relates an obstruction in the airway - body’s reflex is to remove an obstruction- since the tissue is immovable nothing is expelled and the cough is ‘dry’
Pain and discomfort in the chest - consequence of pressure and damage from mass of fibrous tissue and cough.
Weakness and fatigue - results from reduced intake of oxygen - cellular respiration reduced - tiredness
What are the most common allergens that stimulate asthma?
Pollen, animal fur and the faeces of the house dust mite.
It can also be triggered by air pollutants, exercise, anxiety and stress.
One or more asthma allergens causes…
White blood cells on the linings of the bronchi and bronchioles to release a chemical called histamine.
What are the effects of histamine being released from the bronchi/bronchioles linings?
The lining of these airways becomes inflamed
The cells of the epithelial lining secrete larger quantities of mucus than normal
Fluid leaves the capillaries and enters the airways
The muscle surrounding the bronchioles contracts and so constricts the airways
What are the symptoms of asthma?
Difficulty in breathing - due to the constriction of the bronchi and bronchioles, inflamed linings and additional mucus and fluid in them
A wheezing sound when breathing - caused by air going through the constricted bronchioles
A tight feeling in the chest - consequence of not being able to ventilate the lungs properly because of constriction
Coughing - reflex response to obstructed bronchi and bronchioles
What has happened to the elastin in emphysematous lungs?
The elastin has become permanently stretched and the lungs are no longer able to force out all the air from the alveoli. The surface area of the alveoli is reduced and they sometimes burst.
What are the symptoms of emphysema?
Shortness of breath - results in difficulty in exhaling air due to loss of elasticity in lungs. Lungs aren’t emptied so difficult to inhale fresh air. The smaller surface area leads to reduced levels of oxygen in the blood - so patient tries to increase oxygen supply by breathing more rapidly.
Chronic cough - lung damage - reflex- body’s effort to remove damaged tissue and mucus that cannot be removed naturally as cilia on bronchi/bronchioles have been destroyed.
Bluish skin coloration - due to low levels of oxygen in the blood as a result of poor gas exchange.
Healthy lungs contain large quantities of…
The protein - Elastin
Risk factors for lung disease:
Smoking Air pollution Genetics Infections Occupation
