Download - Breathing system
Breathing system
Objectives
To understand the role of the parts of the breathing system
To know how the breathing system is designed for efficiency
To understand gas exchange in the alveolus
To learn the breathing action
To understand factors that affect the health of the breathing system.
Parts and roles
Nose and mouth for inhaling, warming and cleaning inspired air and exhaling waste air
Trachea (wind pipe) takes air down to bronchi
Cartilage rings hold open air tubes
Bronchi: tubes leading to each lung (one bronchus)
Bronchioles subdivided air tubes in lungs – get progressively smaller
Alveoli (1 alveolus) microscopic sacs where gas exchange occurs
Associated parts and roles
Epiglottis prevents food entering trachea
Larynx vibrates in exhaled air to produce sound
Ribs protect lungs and have a role in breathing
Intercostal muscles lift ribs up when they contract
Diaphragm – muscular sheet separating thorax from abdomen. Falls when it contracts to allow breathing in.
Breathing
• http://video.about.com/asthma/How-Lungs-Function.htm
Breathing in (inspiration/inhalation)
Higher pressure outside the body forces air in through the nose
Air pressure in thorax falls
Volume of thorax expands
If deeper breathing is required intercostal muscles contract and lift rib cage up
Diaphragm contracts and drops
Carbon dioxide concentrations rise in the lungs stimulating the breathing response
Breathing out (expiration/exhalation)
Air forced up out of breathing tubes to nose and out to where air pressure is lower.
Air pressure in thoracic cavity rises
Volume of thorax reduced
Diaphragm domes up, rib cage falls
Both sets of muscles relax
Efficiency features of lungs
The lungs must be efficient at exchanging gases to supply sufficient oxygen to the body cells
Large surface area (a tennis court) due to millions of alveoli
Rich blood supply due to millions of capillaries
Thin, moist surface allows rapid diffusion of gases
The lungs can clean themselves
• http://www.youtube.com/watch?v=HiT621PrrO0&feature=related
• http://www.youtube.com/watch?v=miEEluVlemQ
• (both videos cover similar subject matter, i.e. how the lungs clean themselves). It is worth looking at both.
Summary of cleansing features
Hairs in nose trap large particles
Mucus from goblet cells traps smaller particles
Cilia move trapped particles out of lungs and down to stomach
Phagocytes (white blood cells) consume pathogens and other particles on the surface of the lungs
Summary
Oxygen carried by haemoglobin in red blood cells
Oxygen diffuses across the alveolar and capillary walls to join with haemoglobin in the red blood cells
Carbon dioxide carried as bicarbonate ions in the plasma and released across the capillary and alveoli walls to the alveolus
Carbon/soot
Product of incomplete combustion
Irritates the lung lining
Leads to coughing
Builds up in lungs due to death of cilia
Causes inflammation and damage to bronchioles and alveoli
Leads to prolonged cough – chronic bronchitis
Leads to destruction of alveoli
Leads to COPD Chronic obstructive pulmonary disease (also called emphysema)
Reduces uptake of oxygen from lungs – very debilitating
Carbon monoxide
Product of incomplete combustion of carbon
Preferentially binds to haemoglobin
preventing uptake of oxygen
Reduces the amount of oxygen in the blood
Means heart has to work harder
Raises blood pressure
Increased heart strain
TarA complex mixture
of organic compounds
Many are known carcinogens
Kills cilia in lungs
Stops the cleaning mechanism of the
lungs (see soot)
Stimulates uncontrolled
growth of cells lining lung
Leads to lung cancer
NicotineAddictive stimulant
drug
Increases heart rate thus causing
strain to the heart
Causes thickening of the blood
Leads to deposition of fat in
arteries (called plaques)
Results in blockage of arteries
Prevent supply of oxygen to tissues
Leads to tissue death (in heart to
heart attacks)
In extremities to gangrene
Additional medical issuesReduced blood flow and poor blood oxygen concentration inhibits growth and development of the foetus
Babies born premature and underweight
Reduced survival of babies
Leads to impotence
Ages skin
Particularly dangerous in diabetics due to predisposition for quicker ageing of arteries.
Possible links to a wide range of other cancers
Giving up
Many medical practices and workplaces have smoking cessation sessions (UK)
Save money you would spend on cigarettes and reward yourself
Nicotine patches, lozenges and gums
Special medications Zyban and Chantix (may have side affects)
Hypnotherapy and acupuncture.
Willpower
Nicotine inhalators
Other causes of lung disease
Pathogenic e.g. tuberculosis
Asbestos – asbestosis is a very serious form of lung disease leading to cancer
Silicosis common in coal miners. Small particles of silica lodge in lungs causing scar tissue and destroying lung function
Smoke fires. Many poor people in the developing world cook over wood fires. The smoke slowly kills them.
Homework
Produce an information leaflet to discourage people from smoking/to help them give up
Use clear simple language – this is for the general public not scientists
Explain the risks to health (list main diseases)
Explain what causes it (explain role of main toxins)
Use powerful imagery
Be precise
Don’t preach
Smoking leaflet rubricMarks Information Language presentation
1 1 health risk identified Totally inappropriate Just writing
2 All four toxins identified Scientifically correct but too hard to understand
Some visual material
3 At least 4 health risks identified
Some good explanations but other areas too scientific
Visual material integral to understanding/message
4 At least one health risk linked directly to toxin
No evidence of patronizing attitude
Text well spaced round page
5 Most health risks identified No sense of being lectured Good use of emboldened subheadings to attract attention
6 Most health risks correctly linked to toxins
Very clear and mostly understandable
Some imaginative presentational ideas
7 All health risks fully outlined and linked to poisons in smoke
Clearly explained in lay mans terms – fully understandable to all
Exceptionally professional with innovative techniques of presenting information