Unit 1: Section 4 - Respiratory System Flashcards Preview

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What is the main role of the respiratory system?

Supply your blood with oxygen, which then gets delivered to the rest of your body


Describe where the air goes as you breathe in until it reaches your blood?

Air enters the trachea, which splits into two bronchi, each bronchus leading to each lung. Each bronchus branches of into smaller bronchioles which end in alveoli. The oxygen then diffuses across into the blood


Ventilation consists of what two thing?

Inspiration and expiration


What are the four things that happen during inspiration?

1.) intercostal and diaphragm muscles contract
2.) this causes the ribcage to move upwards and outwards and the diaphragm to flatten
3.) this increases the volume of the thorax
4.) decreasing the pressure drawing air into the lungs


What are the four things that happen during expiration?

1.) intercostal and diaphragm muscles relax
2.) this causes the ribcage to move downwards and inwards and the diaphragm to become curved again
3.) this decreases the volume of the thorax
4.) increasing the pressure forcing air out of the lungs


Where does the gas exchange actually happen in the lungs?



What is the lining of the alveoli called?

Alveolar epithelium


What is the centre space of the alveoli called?

Alveolar space


Why do the walls of the alveoli contain elastin?

To allow them to return to their normal shape after inhaling and exhaling air


How does oxygen go from the alveoli into the blood (include what it diffuses across) ?

Oxygen diffuses out of the alveoli across the alveolar endothelium and the capillary endothelium into the haemoglobin in the blood.


What two ways are alveoli adapted for efficient diffusion?

Thin exchange surface - only one cell thick
Large surface area


What is pulmonary ventilation?

The volume of air taken into the lungs in one minute


What is the equation for pulmonary ventilation?

Pulmonary ventilation = tidal volume x ventilation rate


What is tidal volume?

The volume of air in each breathe


What is ventilation rate?

The number of breaths per minute


What is residual air?

Air that is in the lungs that cant be forced out


What bacterium is TB caused by?

mycobacterium tuberculosis


What does TB stand for?

pulmonary tuberculosis


How is TB transmitted?

Through droplet infection, when an infected person coughs or sneezes tiny droplets containing the bacteria are released infecting other people


What are six common symptoms of TB?

cough, coughing up blood, mucus, chest pains, shortness of breath and fatigue


Describe the course of infection when someone is infected with TB?

The bacteria is engulfed by the white blood cells and lies dormant there until the immune system is suppressed. They then become active and destroy the alveoli leading to fibrosis and so decreasing diffusion


What is fibrosis?

Scar tissue in the lungs


Name the two general things that cause fibrosis?

Infection or exposure to certain substances


Why does fibrosis mean the alveoli can hold less air?

Scar tissue is thicker and less elastic and so the alveoli cant expand to hold a greater volume of air


Why does fibrosis reduce gas exchange rate?

Scared tissue is thicker and so the diffusion is slower, and the blood receives less oxygen reducing has exchange rate


What are three symptoms of asthma?

Wheezing, tight chest and shortness of breath


Why does asthma reduce the gas exchange rate?

It causes the smooth muscles lining of the bronchioles to contract and a large amount of mucus to be produced. Constricting the airway so air flow to the alveoli is reduced, reducing the gas exchange rate


What two things is emphysema caused by?

Smoking or long term exposure to air pollution


How does emphysema reduce the gas exchange rate?

Foreign particles in the smoke become trapped in the alveoli, causing inflammation attracting phagocytes to the area. These phagocytes produce an enzymes which breaks down the elastin in the alveoli, this means they cant stretch reducing the surface area for gas exchange, decreasing the gas exchange rate


What are three symptom of emphysema?

Wheezing, shortness of breath and increased breaking rate to try and increase the amount of oxygen in their lungs