Unit 1: Section 4 - Respiratory System Flashcards
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?
- ) intercostal and diaphragm muscles contract
- ) this causes the ribcage to move upwards and outwards and the diaphragm to flatten
- ) this increases the volume of the thorax
- ) decreasing the pressure drawing air into the lungs
What are the four things that happen during expiration?
- ) intercostal and diaphragm muscles relax
- ) this causes the ribcage to move downwards and inwards and the diaphragm to become curved again
- ) this decreases the volume of the thorax
- ) increasing the pressure forcing air out of the lungs
Where does the gas exchange actually happen in the lungs?
Alveoli
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
What is a risk factor?
Something that increases the chance of getting a disease
What does incidence mean?
The number of new cases of a disease
