GAS EXCHANGE AND VENTILATION IN LUNGS Flashcards
what is ventilation
air is constantly moving in and out of lungs
what is inhalation / inspiration
atmospheric air pressure is greater than the lungs forcing air into the alveoli
what is exhalation / expiration
atmospheric air pressure is lower than the lungs forcing air out of the alveoli
describe the trachea and bronchi
made of smooth and elastic muscle, lined with ciliated epithelium
cilia removes mucus
contains goblet cells - make mucus to trap dirt
flexible
c - shaped cartilage - holds it open and prevents it from collapsing
describe bronchioles
made from muscle
constrict to control air flow
describe the alveoli
minute air sacs
collagen and elastic fibers between alveoli
one cell thick walls so close to the capillaries
alveolar epithelium membrane is the gas exchange surface
what is the thorax
between neck and abdomen
what is the diaphragm
dome shape muscle that separates the thorax from the abdomen
describe intercostal muscles
antagonistic pair of muscles
between each rib
what do internal intercostal muscles cause
contract = expiration
what do external intercostal muscles cause
contract = inspiration
describe inhalation
external intercostal muscles contract and internal intercostal muscles relax
diaphragm contracts and flattens
volume of thorax increases as ribcage moves upwards and outwards
pressure of thorax decreases to below atmospheric
atmospheric air forced into the lungs down the pressure gradient
describe exhalation
internal intercostal muscles contract and external intercostals relax
diaphragm relaxes so abdominal organs push upwards
volume of thorax decreases as ribcage moves in
pressure in thorax increases to above atmospheric
air forced out of lungs down the pressure gradient
what is pulmonary ventilation
total volume of air that is moved into the lungs in one minute
tidal volume * breathing rate
what is tidal volume
volume of air taken in in each breath
