Lectures questions with verified answers
About how much time does blood spend in a capillary at rest? Ans✓✓✓
0.75 seconds
acinus Ans✓✓✓ the portion of the lung distal to a terminal bronchial, it
is is made up of alveolar sacs; it is surrounded by pulmonary capillaries
alveocapillary membrane Ans✓✓✓ --Is formed by shared alveolar and
capillary walls
--Structures include the thin membrane of alveolar epithelium, alveolar
basement membrane, interstitial space, capillary basement membrane,
and capillary endothelium (don't need to memorize these structures)
**Gas exchange occurs here**
alveolar microphages Ans✓✓✓ cells within alveoli which ingest foreign
material, and remove it through the lymphatic system
alveolar ventilation Ans✓✓✓ the amount of gas entering the alveoli (the
amount of air available for gas exchange; some air, usually about 150
mL, that is inhaled is "lost" or "left behind" in the anatomic dead space
of the conducting airways)
Alveoli Ans✓✓✓ the primary gas exchange unit of the lungs
,Anatomic dead space Ans✓✓✓ The volume of gas in the conducting
airways (not contributing to gas exchange/respiration)
blood gas barrier Ans✓✓✓ Small capillaries wrap around the enormous
number of alveoli creating an extensive diffusion area; **big surface
area (between 50 and 100 m2) and thin tissue mean lots of air moving
across the blood gas barrier**
Bohr effect Ans✓✓✓ a shift in the oxyhemoglobin dissociation curve
caused by changes in CO2 and H+ concentration in the blood.
This leads to an increase in oxygen released from hemoglobin -- a
protective mechanism (to make sure enough O2 gets to body cells)
carina Ans✓✓✓ Ridge where the trachea divides into the right and left
bronchi.
central chemoreceptors Ans✓✓✓ Receptors located in the central
nervous system that monitor PaCO2 via the pH of cerebrospinal fluid
(CSF) to help regulate ventilation rate and depth
chest wall Ans✓✓✓ • Includes the skin, ribs, and intercostal muscles.
• Functions: Protects the lungs from injury; its muscles, in conjunction
with the diaphragm, perform the muscular work of breathing.
• Thoracic cavity: Is contained by the chest wall and encases the lungs.
, cilia Ans✓✓✓ Are hairlike structures that help propel foreign material
upward to enable it to be coughed up
compliance Ans✓✓✓ --Measures lung and chest wall distensibility and
stiffness (a measure of the lung's ability to stretch/expand)
--this is the reciprocal of elasticity
--this takes into account changes in lung volume with given changes in
applied pressure
conducting airways Ans✓✓✓ passageways and tubes that allow air to
pass into or out of the lungs (no gas exchange occurs here, because
there are no alveoli);
Upper airways: Warms and humidifies air
--Nasopharynx
--Oropharynx
• Larynx: Connects the upper and lower airways
• Lower airways
--Trachea
--Bronchi
--Terminal bronchioles