Respiratory System I Flashcards
major arteries out of the heart from ventricles and what they connect to
aorta: rest of the body
pulmonary trunk L&R arteries: pulmonary circulation
upper respiratory system
nares (nostrils)
nasal cavity
pharynx
lower respiratory system
larynx
trachea
main bronchus
lungs
diaphragm
protection of respiratory epithelium (mucosa)
humidification and warming of air in upper passages
mucous secretion
protection of lungs
mucociliary trapping of foreign matter
ciliary escalator
alveolar macrophages
airway reflexes (cough, sneeze, epiglottis closes glottis during swallowing
goblet cells secrete mucous
conducting zone
nasal cavity to larger bronchioles
function of smooth muscle in bronchiole walls
facilitate airflow regulation
respiratory zone
respiratory bronchiole
alveolar sac
alveoli
what cells is alveolus epithelium composed of
describe them
type I pneumocytes: thin walled simple squamous epithelium facilitates gas exchange
type II: larger surfactant secreting cell
what type of cells are within alveoli
role
macrophages
clear debris and pathogens
surfactant
a mixture of proteins and phospholipids
reduces surface tension from alveolar fluid lining inner surface
prevents alveolar collapse
respiratory membrane layers
simple squamous epithelium of alveolus
alveolar basement membrane
capillary basement membrane
simple squamous epithelium of capillary
contact time between blood and alveolus at rest
minimum time for blood to be fully oxygenated
contact time between blood and alveolus at rest: 0.75s
minimum time for blood to be fully oxygenated: 0.25s
respiratory membrane features
little or no interstitial fluid
elastic with collagen fibres
few fibroblasts
Hb - O2 saturation curve
sigmoidal curve
gentle slope at high pO2
steep slope at low pO2
difference in saturation of haemoglobin at sea level and high altitude
3%
(98 - 95%)
arterial pO2 of blood perfusing resting vs exercising muscle
resting: 40 mmHg
exercising: 20 mmHg
greater proportion of O2 dissociated from Hb in order to meet needs
factors affecting O2 - Hb affinity
pH
temperature
pCO2
2,3-bisphosphoglycerate (BPG)
decrease in pH effect on saturation curve
decreased pH effect on O2 unloading
shifts to the right
decreased pH leads to greater O2 unloading from Hb
decrease in temperature effect on saturation curve
decreased temperature effect on O2 unloading
shifts to the left
decreased temperature leads to decreased O2 unloading from Hb
CO2 transport modes
93% diffuses into RBCs
(23% combines with Hb, 70% is converted to bicarbonate ions)
7% dissolves in plasma
where is carbaminohaemoglobin formed
regions of high pCO2
at the tissues
where does carbaminohaemoglobin dissociate to Hb + CO2
at the lungs
carbonic anhydrase reaction
where and when does this occur
70% of CO2 + H2O <=> H2CO3 (carbonic acid), becomes bicarbonate
within RBCs at the tissues when pCO2 is high
H2CO3 (carbonic acid) spontaneous dissociation at the tissues
why can this continuously occur
forms H+ and HCO3- (bicarbonate ions)
HCO3- ions are exchanged out of RBCs for Cl- ions, maintains neutrality and acts as a buffer
what happens to bicarbonate at the lungs
re-enters RBCs in exchange fro Cl- and reacts with H+ released from Hb
forms carbonic acid (H2CO3)
H2CO3 is broken down to CO2 and H2O by carbonic anhydrase
what do visceral and parietal pleura cover
visceral: surface of the lungs
parietal: mediastinum, superior diaphragm, thoracic wall
