Part III Flashcards
What is the pathway of the airways of the lung?
trachea, bronchi, bronchioles, respiratory bronchioles, alveolar bronchioles, alveolar ducts, alveolar sacs, alveoli
How many alveoli are there?
300 million
What is dead space?
an area where gas exchange cannot occur
How much anatomical dead space is there?
150 mL worth
What constitutes anatomical dead space?
mouth, trachea, bronchi, bronchioles
What is physiological dead space?
anatomical dead space plus non-functional alveoli
How is dead space calculated?
using pure O2 inspiration and measuring nitrogen in expelled air
How much alveolar volume is there in the lung?
2150mL
How do you calculate alveolar volume?
functional residual volume minus dead space
Where is most of the functional residual volume located in the lung after normal expiration?
alveoli
There is a ___ turnover of the ___ in the alveoli.
slow, FRC
How many breaths does it take to completely turn over the FRC?
6-7 breaths
How do you determine the rate of alveolar ventilation?
volume of alveoli = respiratory rate (tital volume - dead space)
What are the different ways the airways are controlled by the autonomic system?
efferent neural control, NANC, afferent nerve control, rapidly adapting receptors, high densities of C fibers
What are the specific categories of efferent control?
sympathetic and parasympathetic
In sympathetics in efferent control, what causes dilation?
beta receptors
How do beta receptors cause dilation?
primarily by an indirect effect via circulating epinephrine
secondarily from sparse innervation (weak)
For parasympathetics, ____ receptors cause ____
muscarinic, constriction
What does NANC stand for?
non-adrenergic, non-cholinergic
What does the inhibitory effect of NANC do?
release of VIP and NO that causes vasodilation
What does stimulation of NANC do?
causes bronchoconstriction, mucous secretion, vascular hyperpermeability, cause, vasodilation, “neurogenic inflammation”
What is the afferent nerve control of the lungs?
it isslow adapting recepors assocated with proximal airways and stretch receptors involved in reflex control of breathing and cough reflex
What are rapidly adapting receptors of the lungs sensitive to?
mechanical stimulation, protons, low chloride solutions, histamine, cigarette smoke, ozone, serotonin, PGF2 alpha
Some of the sensitivities for rapidly adapting receptors of the lung are secondary to what?
mechanical stimulation
What are C fibers?
high density of fibers in the lungs
What do C fibers contain?
neuropeptides (substance P, neurokinin A, calcitonin gene related peptide)
What are C fibers selectively stimulated by?
capsasin
What are other things that are activated by C fibers?
bradykinin, protons, hyperosmole solutions, cigarette smoke
What constricts the airways?
histamine binding to H1 receptors and prostaglandin F series
What dilates the airways?
histamine binding to H2 receptors and prostaglandin E series
What is the airway mediated by when environmental pollution is inhaled?
it is mediated by the parasympathetic reflex and local constrictor responses
What is the normal HCO3 level for the body?
24mEq/L
What does metabolic acidosis do?
(
What does metabolic alkalosis do?
(>24mEq/L) decreases ventilation
What HCO3 regulated by?
kidneys
What is the normal levels of CO2?
40mmHg
What does respiratory acidosis do?
(>40mmHg) increases ventilation
What does respiratory alkalosis do?
(
What is CO2 regulated by?
lungs
