3.3.2 Respiratory diseases

what is a pollutant and give examples

a substance released into the environment that harms organisms or the environment. e.g

• tobacco smoke - contains tar, CO, nicotine

• asbestos - cause lung cancer

• fungal spores - e.g Aspergillus mould which can weaken immune system

what are the short term effects of pollutants on the respiratory system

• irritation to nose + throat

• allergic reactions

• make existing medical conditions worse e.g asthma

• cause upper respiratory infections e.g pneumonia/bronchitis

what are the long term effects of pollutants on the respiratory system

• chronic respiratory diseases

• COPD

what is an acute disease

disease that has:

• rapid onset

• short duration

• relatively quick recovery time

what is a chronic disease

a diseases that’s:

• slow onset

• long duration

• slow revoery

causes of lung cancer

• DNA mutations caused by carcinogens e.g in tobacco smoke

• leads to formation of oncogenes from proto-oncogenes +/or mutated tumour suppressor genes e.g p53

• uncontrolled mitosis

• formation of tumour (accumulation of faulty cells)

• tumour spreads via metastasis

symptoms of lung cancer

• early stages = no symptoms (chronic disease)

• wheezing

• shortness of breath

  • tumour may block airways

• persistent cough

• fatigue

causes of chronic bronchitis

• tar deposited in airways

• causes hypertrophy of goblet cells

• more mucus is produced

• excess mucus paralyses cilia

• cilia unable to waft mucus up throat so mucus accumulates

• pathogens are trapped in the mucus —> inc risk of infections

• mucus builds up in alveoli —> inc diffusion distance for O2/CO2

• mucus reduces lumen width of bronchioles/bronchi

• INFLAMMATION

symptoms of chronic bronchitis

• shortness of breath

• wheezing

• persistent cough

• blood-stained sputum

• fatigue

are there treatments for chronic bronchitis

• no

• only steroids/bronchodilators can be taken to reduce symptoms

outline the cause of emphysema

• accumulation of mucus trapped bacteria in alveoli

• attracts many phagocytes

• phagocytes release elastase —> digests elastic tissue to reach site of infection + hydrolyses peptide bonds in elastin (found in alveoli walls)

• smokers have a deactivated inhibitor alpha-1 antitrypsin (meant to prevent damage in lungs)

• alveoli become enlarged and burst

• reduces SA for gas exchange

• elastin permanently stretched so no more recoil

• harder to remove stale air from lungs

symptoms of emphysema

• shortness of breath

• difficulty exhaling —> due to lack of passive elastic recoil as elastin is stretched

• barrel chest —> continuous use of intercostal muscles

• partial pressure of O2 in blood decreased

what changes does emphysema do to the alveoli + bronchioles

Alveoli:

• fewer number

• larger air spaces

• smaller SA for GE

Bronchioles:

• no cilia

• build up of scar tissue

• less elastin + smooth muscle

what are emphysema + bronchitis known as

• COPD - chronic obstructive pulmonary disease

• emphysema occurs simultaneously with bronchitis

• both treated together

cause of asthma

• genetic + environmental factors

risk factors of asthma

• smoking cigarettes

• inhalation of air pollutants

• inhalation of dust mites/mould spores

• allergies

symptoms of asthma

• coughing

• wheezing

• breathing difficulties

• chest tightness

explain the symptoms of asthma

• cells lining the bronchioles release histamines

• histamines cause inflammation of epithelial cells + stimulates goblet cells to release mucus

• contraction of smooth muscle in bronchi/bronchioles

• causes more inflammation

• reduces lumen size of bronchioles/bronchi

• restricts air flow

what are the treatments for asthma

• beta agonists

• corticosteroids

how do beta-agonsits work

• short term use

• provide immediate relief

• chemicals attach to csm of smooth muscle cells in bronchioles

• this causes smooth muscle to relax —> widens lumen

• increases air flow

• used before exercise or in an asthma attack

what are beta agonists also known as

bronchodilators

how do corticosteroids work in treating asthma

• long term use

• taken daily

• reduces sensitivity of airway lining —> decreases likelihood + severity of asthma attack

• reduces inflammation of bronchi

where is theophylline found + what’s it used for

• found in cocoa beans (theobroma cacao)

• treats COPD/ASTHMA —> relaxes smooth muscle in bronchi + anti inflammatory

where is topotecan found + what’s it used for

• found in camptotheca acuminata

• treats lung cancer + other bacteriol infections —> anti-cancer + anti-microbial properties

where is aspirin found + what’s it’s use

• found in willow (salix alba)

• used as a painkiller + anti-thrombic —> anti inflammatory properties