Lecture 26 Flashcards
What are the 5 main functions of the respiratory system?
Gas exchange condition inspired air filter and clean air homeostatic regulation of pH vocalization
What are the muscles used for ventilation?
Inspiration: external intercostals, scalenes, sternocleidomastoids, diaphragm
Passive expiration: relaxation of inspiratory muscles
Active expiration: internal intercostals, abdominals
Describe the structure and function of the pleural membranes
surrounds the lungs. visceral (inner) and parietal (outer) pleural membrane. Composed of secretory epithelial cells and connective tissue. Have intrapleural fluid between the two to decrease friction (allow the two to slide) and keep the lungs attached to the thoracic cavity wall and inflated.
What is the main role of the airways?
warm the air to body temperature, add moisture/water vapour to the air, filter out foreign substances
Describe how mucus gets moved in the airways
submucosal gland and epithelial cells produce saline layer underneath the mucus layer, this allows the mucus to be moved via cilia
cystic fibrosis occurs when there isn’t enough of the saline layer and thus the mucus can’t be moved
Mucus layer traps inhaled particles
How is resistance to air flow regulated?
depends on length, viscosity, and radius. Length/viscosity can’t be changed, only resistance. Can’t change radius in the bronchi or trachea (has cartilage to keep it open) but can change the radius of the bronchi
How is bronchi radius modulated?
Vasodilation
Paracrines = CO2
SNS = epinephrine on β2 receptors causes smooth muscle to relax
Vasoconstriction
Paracrines: histamines from mast cells (allergic response)
PNS = acetylcholine on muscarinic receptors causes relaxation of smooth muscle
What are the two types of alveoli?
Type I (95%) = gas exchange Type II (5%) = produces surfactant to reduce surface tension and makes it easier for the alveoli to expand and prevent it from collapsing
