Asthma flash card
What is a bronchospasm?
A sudden constriction of the muscles in the walls of the bronchi
What controls the diameter of the airways?
the smooth muscles surrounding the bronchioles
What are the 2 main types of asthma?
Intrinsic and extrinsic
What is intrinsic asthma
Not triggered by external allergens, usually occurs in adulthood, arises from internal factors e.g infection, exercise
What are the symptoms of intrinsic asthma?
wheezing, shortness of breath, coughing, chest tightness
What is the pathophysiology of asthma
The airway becomes hyper-responsive, leading to an exaggerated bronchoconstrictive response to stimuli, this results in bronchoconstriction and inflammation
What is the treatment for intrinsic asthma?
Bronchodilators, inhaled corticosteroids
What is extrinsic asthma?
Caused by an allergen
What are some triggers of extrinsic asthma?
Pollen, dust mites, mold spores, food allergies
What is the pathophysiology of extrinsic asthma?
When exposed to an allergen, IgE antibodies on the surface of mast cells bind to the allergen, leading to mast cell degranulation. The next time you are exposed to the same allergen, the IgE antibodies recognise this and causes the mast cells to release chemicals such as histamine which leads to: bronchoconstriction, mucus production, inflammation
Where is mucus produced?
in the airways by goblet cells
What happens when you cough excessively?
Overstimulation of the vagus nerve, causes bronchoconstriction and bronchospasm. Because of this, air gets trapped in the lungs making it hard to breathe properly and it can lead to the collapse of the bronchi when someone tries to forcefully exhale
What is atelectasis?
when the lung tissue collapses due to the complete blockage of the airways by mucus
What is respiratory acidosis?
When there is a build up of co2 in the blood
What is IgE
Immunoglobulin - a type of antibody produced by the immune system - specifically involved in allergic reactions
What is histamine?
A chemical that causes blood vessels to become leaky - leading to oedema (swelling)
What are kinins?
Chemicals that cause the blood vessels to widen (vasodilation) and the muscles around the airways to tighten (bronchoconstriction)
What do prostaglandins do?
Cause blood vessels to narrow (vasoconstriction) which can lower blood pressure and reduce blood flow to the lungs
What happens once atelectasis has occurred?
Hypoxia is induced as air cannot diffuse through the affected areas, respiratory muscle activity increases as the demand for oxygen increases - this increased effort leads to laboured breathing
What happens when metabolic and respiratory acidosis occurs?
hypoxaemia causes the pulmonary vessels to narrow (vasoconstriction) this makes it harder for blood to flow through the lungs, increasing pressure - this increases the workload of the right side of the heart as it now has to work harder to push blood through to the lungs, which puts extra stress on the right ventricle
What happens during an asthma attack?
The number of leukocytes (white blood cells) increases, particularly eosinophils, however they are over activated, they release chemicals that cause bronchoconstriction and inflammation, resulting in long term damage and narrowing, making the individual more prone to asthma attacks
What are eosinophils?
A type of white blood cell that can help the body fight off parasites and respond to allergens. They release chemical mediators such as leukotrienes that cause the smooth muscle around the airways to tighten, increase mucus production and lead to prolonged inflammation
What are chemotactic factors?
Signals that attract white blood cells to the site of inflammation
What are cytokines?
Proteins released by mast cells that are crucial for cell-to-cell communication e.g for white blood cells to move to the inflamed area
What do mast cells do in asthma?
Release chemotactic factors and cytokines, drawing more white blood cells into the lungs and airways - this brings in more cells that increase inflammation and make the airways tighten and more swollen resulting in more airway blockage and worse hypoxia