C2: Functions of respiratory system Flashcards
what are the intercostal muscles?
-group of muscles that are located in between ribs and help move thoracic cavity
what are the external intercostal muscles responsible for?
-forced and quiet inhalation
-raise and expand the chest cavity
what are the internal intercostal muscles responsible for?
-forced exhalation
-they depress the ribs and decrease space in the chest cavity
what is the diaphragm?
-dome shaped sheet of muscle and tendon
-main muscle of respiration
-fibrous tissue that separates thoracic cavity and abdomen
contract- up and out
relaxed- down and in
what is meant by mechanism of breathing?
how it works
if the volume in the TC increases what happens to the pressure?
decreases
whats boyles law?
volume increase= pressure decrease
volume decrease=pressure increase
what happens during inspiration(breathing in) in general?
-volume of TC increases so pressure in lungs decreases.
-Atmospheric air is therefore at higher pressure so air is forced in the body
what happens during expiration(breathing out) in general?
-TC returns to original size
-decrease in volume= increase in pressure
-pressure in lungs is higher than atmospheric air pressure do air is forced out
why does it depend on pressure whether or not air is forced in or out?
because pressure always ‘diffuses’ to where there is less pressure
what do external muscles do?
-pulls the muscle out
what do internal muscles do?
-pull the muscles in
what happens in gas exchange?
-blood becomes oxygenated
-diffusion of oxygen into RBC and removal of CO2
where does gas exchange happen?
in alveoli and capillaries
how are capillaries suitable for gas exchange?
-they are narrow(1 cell thick) and so slow blood flow so gas exchange happens more often
what are the 4 stages of gas exchange?
-Pulmonary Ventilation
-Pulmonary Gas exchange
-Gas transport
-Systemic Gas exchange
what happens during pulmonary ventilation?
oxygen is inhaled into the alveoli
what happens during pulmonary gas exchange?
the oxygen is moved from the alveoli into the capillaries
what happens during gas transport?
oxygen is moved around the body via the blood stream
what happens during systemic gas exchange?
-diffusion of oxygen into working muscle cells and removal of CO2
-O2 molecules bind to haemoglobin which transports in body via erythrocytes.
where does external respiration occur?
-between alveoli and pulmonary capillaries
explain what happens in external respiration
-There is a high concentration of CO2 in the capillaries and a low concentration in the alveoli, so CO2 diffuses into alveoli
-There is a higher concentration of O2 in the alveoli than the capillaries so O2 diffuses into the capillaries
Where does internal respiration occur?
-between systemic capillaries and skeletal muscles
what are the 4 different types of lung volumes?
-tidal volumes
-vital capacity
-residual volume
-total capacity
