respiratory important Flashcards
inspiration
intercostal muscles = contract
diaphragm = contracts
volume = increases
pressure = decreases
chest wall moves away from lung surface and parietal pleura moves away from visceral slightly
pressure enough to overcome elastic recoil, lungs expand - air forced in
what is the innervation of the diaphragm
phrenic nerve C3,4,,5
expiration
intercostal muscles = relaxes
diaphragm = relaxes
volume = decreases
pressure = increases
conducting airways
No alveoli and no exchange with blood Trachea Main Bronchus(Right and Left) Lobar Bronchus Segmental Bronchus Terminal Bronchiole
respiratory airways
Contains alveoli and gas exchange with blood
Respiratory Bronchiole
Alveolar Duct
Alveolar Sac
what type of epithelium is respiratory epithelium
Ciliated pseudostratified columnar epithelium
type 1 pneumocytes
95% of alveolar area, thin barrier for diffusion, connected by tight junctions.
type 2 pneumocytes
60% of total number of cells, secrete
Surfactant and decreases surface tension
alveolar macrophages
Immune cells
Derived from monocytes
Ingest bacteria and particles
what are the layers of gas exchange
- Fluid lining alveoli
- Layer of epithelial cells (type I pneumocytes)
- Basement membrane of ^ cells
- Interstitial space between alveoli epithelium and capillary endothelial cells
- Basement membrane of capillary endothelium
- Capillary endothelial cells
- Red blood cell
describe the binding of oxygen to haem
Oxygen bindsreversibly tohaem, so eachhaemoglobinmolecule can carry up to fouroxygenmolecules. Haemoglobinis an allosteric protein; thebindingofoxygento onehaemgroup increases theoxygenaffinity within the remaininghaemgroups
what shifts the oxygen dissociation curve left?
decreased temperature
decreased 2,3-DPG
decreased H+
CO
what shifts the oxygen dissociation curve right
(reduced affinity)
increased temperature
increased 2,3-DPG
increased H+
why is there V/Q mismatch in healthy people
natural inequality of 5mmHg due to gravitational effects
increased filling of blood vessels at the bottom of the lung
examples of V/Q mismatch
- There may be ventilated alveoli but no blood supply at all (known as dead space or wasted ventilation) due to a blood clot for example
- There may be adequate blood flow through the areas of the lung but there is no ventilation (this is termed shunt) due to collapsed alveoli
what are 2 local homeostatic responses to V/Q mismatch?
Hypoxic pulmonary constriction
- vasoconstriction to divert blood away from the poorly ventilated area
Local bronchoconstriction
- diverts airflow away to areas of the lung with better perfusion
inspiratory reserve volume (IRV)
amount of air in excess tidal inspiration that can be inhaled with maximum volume
expiratory reserve volume (ERV)
amount of air in excess tidal expiration that can be exhaled with maximum effort
residual volume (RV)
amount of air remaining in the lungs after maximum expiration, keeps alveoli inflated between breaths and mixes with fresh air on next inspiration
vital capacity (VC)
amount of air that can be exhaled with maximum effort after maximum inspiration
functional residual capacity (FRC)
amount of air remaining in the lungs after a normal tidal expiration
inspiration capacity (IC)
maximum amount of air that can be inhaled after a normal tidal expiration
total lung capacity (TLC)
maximum amount of air the lungs can contain
tidal volume (TV)
amount of air inhaled or exhaled in one breath