Respiratory System Flashcards
Breathing in is known as…
Inspiration
Breathing out is known as…
Expiration
How does inspiration work?
Diaphragm flattens, intercostal muscle contracts causing rib cages to move up and out, volume increases causing air to fill lungs
How does expiration work?
Diaphragm returns to done shale, intercostal muscle relaxes causing rib cages to move down and in, volume decrease causing air to leave lungs
What is in the upper respiratory tract?
Nasal cavity, larynx (voice box & glottis), pharynx (throat), trachea
What is the lower respiratory tract?
Bronchi & bronchioles
What does the bronchioles open up into?
Alveolar ducts surrounded by capillaries
What occurs at the alveoli
Gas exchange (oxygen and carbon dioxide)
What in the alveoli structure aids gas exchange?
Thin wall, large surface area:volume, fluid lined (allowing gas to diffuse), surrounded by many capillaries
Name the 4 stages of respiration
Breathing (entry and exit of air from lungs), external respiration (exchange of gas between blood and air), internal respiration (exchange of gas between blood and tissue), cellular respiration (ATP production)
Name a common lung function test?
Spirometry - measures how much air can be expelled in the first second (forced expiratory volume a.k.a FEV1)
Name the 4 major volumes of breathing
Tidal volume, vital capacity, residual volume, dead air space
What is tidal volume?
When lungs are at rest a small amount of air is moving in and out (~500ml)
What is vital capacity?
Maximum amount of air a person can expel after a full inhalation (3-5L)
What is residual volume?
The volume of air remaining in the lungs after exhaling (1L)
What is dead air space?
The air inhaled that doesn’t reach lungs
What air isn’t involved in gaseous exchange with the blood?
Residual volume and dead air space
What principle governs gaseous exchange in the blood?
Diffusion
Describe external respiration
Alveolar air has a high partial pressure of O2, blood entering pulmonary capillaries are low in O2, O2 diffuses into plasma than RBC to make oxyhaemoglobin.
Blood in capillaries have a higher pCO2 than air so CO2 diffuses out of blood(bonds to haemoglobin to make carboxyhaemoglobin and as bicarbonate (converted by enzyme carbonic anhydrase found in RBCs)
What causes altitude sickness?
Air pressure drops as altitude increases. As the external pressure is less, less air fills the lungs during inspiration.
What happens when external pressure increases e.g. diving?
As pressure increases the volume of the lungs decreases (Boyles law) less lung capacity= less O2
What is the diving reflex?
When cold water hits the forehead, the body holds its breath, decreases heart rate, blood prioritises vital organs (brain & heart)
What are the pH and temp conditions in the lungs?
pH 7.4, 37°C
What are the pH and temp conditions in body tissue?
pH 7.38, 38°C
How does temperature and pH affect breathing?
Higher pH and lower temperature favours uptake of oxygen by haemoglobin in lungs. Lower pH and higher temperature favour the release of oxygen in tissue
