Connects the upper and lower airways. Consists of the endolarynx, which forms the vocal cords.
respiratory bronchioles, alveolar ducts, alveoli. The structures that participate in gas exchange.
Pores of Kohn
Allow pressure to equalize between adjacent alveoli. Tiny passages that permit some air to pass through the septa from alveolus to alveolus
The pulmonary circulation has ___________ pressure and resistance than systemic circulation
Lower (18mm Hg, 1/5 of the pressure of the systemic circulation)
Pulmonary and Bronchial Circulation function to:
1) Facilitate gas exchange
2) Deliver nutrients to lung tissues
3) Act as a reservoir for the left ventricle
4) Filter and remove debris from the circulation
Usually how much of the pulmonary vessels are perfused at any given time?
1/3 (When carciac output increases, additional vessels become perfused and the mean arterial pressure remains low.)
The most effective way to measure the adequacy of alveolar ventilation is to measure____________.
What is unique about bronchial circulation?
Not all of its capillaries drain into its own venous system, but empty into the pulmonary vein and contribute to the normal venous admixture.
Hypoxic pulmonary vasoconstriction
Vasoconstriction cause by alveolar and pulmonary venous hypoxia. The most important cause of pulmonary artery constriction is low alveolar partial pressure of oxygen (PAO2)
portion of tidal volume that reaches alveoli; during expiration, part of this alveolar gas remains in the conducting airways and moves back into the alveoli with next inspiration
anatomic dead space
portion of tidal volume that remains in conducting airways; approximately 1/3 of each breath
Functional residual capacity (FRC)
amount of gas remaining in the lung at the end of a passive expiration (RV + ERV)
Inspiratory Capacity (IC)
amount of gas that can be inspired after a passive expiration (includes Vt and IRV)
total lung capacity (TLC)
total gas volume in the lung when it is maximally inflated (RV + ERV + Vt + IRV)
vital capacity (VC)
maximum amount of gas that can be displaced (expired) from the lung (IRV + Vt + ERV)
The basic automatic rhythm of respiration is set by the _____________
Dorsal respiratory group (DRG) located in the respiratory center
Which group of neurons receives afferent impulses from peripheral chemoreceptors in the carotid and aortic bodies?
the Dorsal respiratory group (DRG)
Ventral Respiratory Group (VRG)
located in the medulla; almost inactive during normal, quiet respiration; becomes active when increased ventilation effort is required
pneumotaxic center and apneustic center
situated in the pons; do not generate primary rhythm, but act as modifiers of the inspiratory depth and rate established in the medullary centers
breathing can also be modified by the __________, _____________, and ________________.
cortex, limbic system, hypothalamus
in the lung conducting airways; sensitive to noxious aerosols and dust; initiate cough reflex
found in smooth muscles of airways and are sensitive to increases in size or volume.
located near alveolar capillaries; sensitive to decrease in alveolar size due to edema and fibrosis; stimulate rapid, shallow breathing. Also stimulates laryngeal constriction on expiration and mucous secretion; hypotension; bradycardia
monitor arterial blood indirectly by sensing changes in pH of the CSF. Sensitive to hydrogen ion concentration in the CSF. Sensitive to very small changes.
located in the aortic bodies, aortic arch and carotid bodies and are sensitive to oxygen levels (PaO2) in arterial blood. Not as sensitive as the central chemoreceptors.
measure of lung and chest wall distensibility and represents the relative ease with which these structures can be stretched.
tendency of a structure to resist stretching and when stretched, return to its original shape
Surfactant proteins SP-B and SP-C
small hydrophobic molecules that have a detergent-like effect that separates the liquid molecules, thereby decreasing aleveolar surface tension.
Surfactant proteins SP-A and SP-D
consists of large hydrophillic molecules called collectins (pattern recognition molecules) that are capable of inhibiting foreign pathogens.
Normally very low. 1/2 - 2/3 of resistance occurs in the nose. Determined by the length, radius, and cross-sectional area of the airway and density, viscosity and velocity of the gas.
Which side of the oxyhemoglobin dissociation curve represents the situation of blood in the lungs?
Left (increased affinity)
Which side of the oxyhemoglobin dissociation curve represents the situation of the blood in the tissues?
Right (decreased affinity)
List three factors that cause the oxyhemoglobin dissociation curve to shift to the right (decreased affinity)?
Increase in PaCO2 (hypercapnea), increase in acidosis, hyperthermia
A shift to the left (increased affinity) in the oxyhemoglobin dissociation curve may be caused by...
alkalosis, hypocapnia (decrease in PaCO2), hypothermia, decrease in 2,3-diphosphoglycerate, carbon monoxide
Measure of the rate of gas diffusion across the alveolocapillary membrane. Determines how much CO2 is taken up by the blood and dividing this amount by the pressure gradient across the alveocapillary membrane
Which alterations involved with aging are considered normal?
Increased flow resistance, alterations in gas exchange, loss of recoil.