Flashcards in Respiratory Physiology (Part 1) Deck (72)
What is the function of the respiratory system?
To exchange oxygen and carbon dioxide between the environment and the cells of the body
The structures of the respiratory system are subdivided into 2 zones, what are they?
- The conducting zone
- The respiratory zone
What structures are included in the conducting zone?
- terminal bronchioles
What are the funcitons of the conducting zone?
Bring air into and out of the respiratory zone for gas exchange and to warm, humidify, and filter the air before it reaches the critical gas exchange region
What is the main conducting airway?
The trachea divides into how many different divisions?
What lines the conducting airways and what are their function?
Mucus-secreting and ciliated cells that function to remove inhaled particles
Do the walls of the conducting airways contain smooth muscle?
Describe sympathetic innervation of smooth muscle in the conducting airways
Sympathetic adrenergic neurons activate beta2 receptors which leads to relaxation and dilation of the airways
Describe parasympathetic innervation of smooth muscle in the conducting airways
Parasympathetic cholinergic neurons activate muscarinic receptors, which leads to contraction and constriction of the airways
How are beta2-adrenergic agonists help treat asthma?
They are used to dilate the airways
The alveoli lined structures of the respiratory zone participate in what?
What structures are included in the respiratory zone?
- respiratory bronchioles
- alveolar ducts
- alveolar sacs
Why are the respiratory bronchioles considered transitional structures?
They have cilia and smooth muscle like the conducting airways, but are also considered part of the gas exchange region because alveoli occasionally bud off their walls
What lines the alveolar ducts and alveolar sacs?
What are alveoli?
Pouchlike envaginations found in the walls of the respiratory zone in which gas exchange occurs
Why can the exchange of oxygen and carbon dioxide between alveolar gas and pulmonary capillary blood occur rapidly and efficiently?
Because the alveolar walls are thin and have a large surface area for diffusion
What are the epithelial cells that line the alveolar walls called?
type I and II pneumocytes
What do the type II pneumocytes synthesize?
Pulmonary surfactant which have regenerative capacity for the type I and II pneumocytes
What are the phagocytic cells in the alveoli called?
Why is pulmonary blood flow not distributed evenly in the lungs?
Because of gravitational effects
When a person is standing, blood flow is ____ at the apex and _____ at the base of the lungs
What happens to the gravitational effects when a person is supine?
How is the regulation of pulmonary blood flow accomplished?
by altering the resistance of the pulmonary arterioles
What controls changes in pulmonary arteriolar resistance?
local factors, mainly oxygen
What is bronchial circulation?
The blood supply to the conducting airways (which do not participate in gas exchange) and is a very small fraction of the total pulmonary blood flow
Static volumes of the lungs are measured with what?
What does normal tidal volume equal?
What does normal tidal volume include?
The volume of air that fills the alveoli plus the volume of air that fills the airways