mammalian gas exchange system Flashcards
describe the basic structure of the human gas exchange system
the trachea divides into 2 bronchi (one to each lung) which further divide into bronchioles that branch to the alveoli
describe the structure of the trachea
contain C-shaped cartilage rings for support, smooth muscle and elastic tissue
what adaptations does the trachea lining have
lined with ciliated epithelial cells and goblet cells
what do goblet cells do?
produce mucus
what do ciliated epithelial cells do?
move mucus (and trapped particles) up the trachea until it can be swallowed - cilia beat to enable this
describe the function of cartilage in the trachea
supported by C-shaped cartilage rings to keep it open/supported so air can move in and out all the time
describe the structure of the bronchi
C-shaped cartilage, smooth muscle and elastic tissue from trachea continue into the bronchi
describe the structure of the bronchioles
contains bands of smooth muscle with elastic tissue surrounding them
describe the function of elastic tissue in the bronchi/bronchioles
allow lungs to recoil back into shape after they expanded during inspiration
what are 3 adaptations of alveoli
- large surface area
- rich blood supply to maintain concentration gradient
- thin walls - short diffusion distance
what type of cell makes up the capillaries?
endothelial cells
what type of cell makes up the alveoli?
epithelial cells (1 cell thick)
what is an example of a pressure gradient?
trachea –> alveoli
what is an example of a diffusion gradient?
alveoli –> blood
describe the process of human ventilation (inspiration)
- external intercostal muscles contract
- ribs move up and out
- diaphragm contracts and flattens
- volume of lungs increases, pressure decreases (lower than atmosphere so air moves in)
describe the process of human ventilation (expiration)
- external intercostal muscles relax
- (for forced exhalation): internal intercostal muscles contract
- ribs move down
- diaphragm moves up and relaxes
- volume of lungs decreases, pressure increases (higher than atmosphere so air moves out)
what happens during forced expiration?
- internal intercostal muscles contract to pull ribs in hard and fast
- external intercostal muscles further relax
what are the intercostal muscles considered?
antagonistic pairs
define antagonistic pair + example
a muscle (or pair of something) that opposes the actions of the other
- eg. biceps contract when triceps relax
describe the relationship between pressure and volume
pressure is inversely proportional to volume (increase volume = decrease pressure)
what process is expiration considered
passive
what process is inspiration considered?
active
where are intercostal muscles located
between the ribs
what is tidal volume
volume of air displaced by the lungs per breath at rest (dm3)
what is breathing rate
number of breaths taken each minute (breaths per min)
what is FEV1
- forced expiratory volume
- the max volume of air that can be breathed out in 1s
what is vital capacity?
maximum volume that can be exhaled after maximum inhalation
what does a spirometer measure?
volume and function of the lungs + oxygen uptake
how does a spirometer work?
inhalation and exhalation move the lid of the spirometer recorded by a data logger
- Co2 exhaled is absorbed by soda lime, so the volume of O2 can be measured
what is the approx. volume of air in each breath in adults
0.4-0.5 dm3
what is the average number of breaths per min
15
what are 5 examples of lung diseases
- cystic fibrosis
- asthma
- TB
- COVID
- emphacema
