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RESPIRATORY SYSTEM

Ventilation – Movement of air into and out of the lungs in two stages: inspiration and expiration – controlled by the movement of ribcage and diaphragm

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Gas exchange – Diffusion of oxygen and carbon dioxide to and from the blood at the alveoli and the respiring tissue

 

Cell respiration – Production of ATP at cellular level at mitochondria

ALVEOLI

  • Increases surface area to volume ratio for gas exchange

  • Each surrounded by rich network of capillaries

  • High concentration gradient of oxygen and carbon dioxide

  • Thin membrane of blood capillaries and alveoli

    • Short diffusion path

  • Surfaces are wet – gases are dissolved

 

TYPE 1 PNEUMOCYTE – Gas exchange

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TYPE 2 PNEUMOCYTE – Secretes surfactant to prevent sides of alveolus adhering

alveoli.PNG
2.PNG

ASTHMA – Causes airways to narrow and swell

  • Environmental and genetic factors

  • Inhalers contain hormones which relax bronchi muscles to open up and allow air to flow normally, during asthma attack

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LUNG CANCER

Most common form of cancer

Difficult to treat and high mortality rate

Vast majority of lung cancers caused due to smoking

Causes of lung cancer:

  • Asbestos dust particles lodge in the lungs and cannot be broken down

  • Smoking (cigarettes, cigars, pipe tobacco)

  • Passive smoking (breathing in someone else's cigarette smoke); about 3% of all cases

  • Air pollution: diesel exhaust fumes contain many carcinogens (compounds causing cancer)

  • Radon gas: in some parts of the world there is a higher concentration of this radioactive gas. It emits alpha particles, which can cause mutations when inhaled.

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EMPHYSEMA

Caused by long term exposure to cigarettes and other pollutants

Narrowing of small airways and breakdown of lung tissue

Alveoli become less elastic, making ventilation more difficult

GAS EXCHANGE

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