Exam 3- Chapter 21 Flashcards
boyle’s law
gas pressure + volume are inversely related
as volume increases, pressure…
decreases
as volume decreases, pressure…
increases
how does boyle’s law relate to inspiration
as lung volume increases -> intrapulmonary pressure decreases which causes air to rush into lungs
how does boyle’s law relate to expiration
as lung volume decreases-> intrapulmonary pressure increases causing air to move out of lungs
atmospheric pressure
-created by the pull of gravity on air around us
-at sea level AP=760 mm Hg
-increases above sea level
-decreases below sea level
intrapulmonary pressure
-air pressure within the alveoli
-rises + falls w inspiration & expiration
-always eventually equalizes with AP
intrapleural pressure
-air pressure with pleural cavity
-rises + falls w inspiration & expiration
-does NOT equal atmospheric pressure, about 4 mm Hg less than intrapulmonary pressure
inspiration is ______
active
def: involve muscle contraction
expiration is ______
passive
def: does not involve muscle contaction
what factors affect ventilation
-air pressure
-airway resistance
-alveolar surface tension
-pulmonary compliance
airway resistance
anything that impedes air flow in respiratory tract
resistance ______ during inspiration
decreases
resistance ______ during expiration
increases
diameter of bronchioles is controlled by…
smooth muscle contraction & relaxation
bronchodialation
increases diameter of bronchioles
bronchoconstriction
decreases diameter of bronchioles
alveolar surface tension
alveoli are connected by thin liquid film made of water creating gas
atelectasis
high amounts of unopposed surface tension causes alveolus to collapse during expiration
what produces surfactant
type ll alveolar cells
pulmonary compliance
ability of lungs + chest walls to stretch
what are the 3 factors that determine pulmonary compliance
-degree of alveolar surface tension
-denstenibility of elastic tissue
-ability for chest walls to move or stretch during inspiration
spirometer
produces graph that records normal & forced inspiration + expiration
tidal volume
around 500 ml
volume of air exchanged with normal breathing
inspiratory reserve volume
maximum amount of air that can be forcibly inspired after the normal inspiration
expiratory reserve volume
maximum amount of air that can be forcibly expired after the normal expiration
residual volume
volume of air that remains in the lungs after forced expiration
inspiratory capacitiy
total amount of air that can be inspired
TV+IRV
functional residual capicity
total amount of air that normally remains in the lungs after tidal expiration (normal breathing)
ERV+RV
vital capacity
total amount of exchangeable air that can be moved in & out of lungs
TV+IRV+ERV
total lung capacity
sum of all pulmonary volumes; represents total amount of exchangeable and nonexchangeable air in lungs
TV+IRV+ERV+RV
dalton’s law
each gas in mixture exerts it’s own pressure (partial pressure)
total pressure of gas mixture is the sum of partial pressure of all its component gasses.
pulmonary gas exchange is ________ respiration
external
-pulmonary gas exchange is is the diffusion of gasses between alveoli and blood
tissue gas exchange is ________ respiration
internal
-tissue gas exchange is the diffusion of gasses between blood and tissues
factors affecting pulmonary gas exchange
-surface area of respiratory membrane
-thickness of membrane
-ventilation-perfusion matching
def: degree of match between the amount of air reaching alveoli (ventilation) & amount of blood flow (perfusion) in pulmonary capillaries.
hypoxemia
low blood oxygen level
hypercapnia
high blood carbon dioxide level
factors affecting tissue gas exchange
-surface area available for gas exchange (of branched systemic capillaries)
-distance over which diffusion must occur
-perfusion of tissue
-about 1.5% of inspired oxygen is dissolved in _____
-majority of oxygen is transported in plasma by _________
plasma
hemoglobin (Hb)
affinity
bond strnegth with which Hb binds to oxygen
majorty of total CO2 is transported in the form of _______________ ____
bicarbonate ions
(are imporant to blood pH homeostasis)
buffer
a solution that can resist pH change of an acidic or basic component
if hydrogen ions are added they bind to ___________ ___ to form _________ _____
bicarbonate ions
carbonic acid
dyspnea
shortness of breath
eupnea
normal breathing
ventral respiratory group
-anterior portion of medulla!!
-responsible for rhythmicity of breathing!!!
-VRG neurons send impulses along spinal cord that trigger action potential in:
-intercostal nerves (innervates external intercostal muscles
-phrenic nerve (innervates diaphragm)
dorsal respiratory group
-posterior portion of medulla !!
-responsible for inspiration !!
-sends impulse along spinal cord that trigger ction potential in:
-intercostal nerves (innervates external intercostal muscles
-phrenic nerve (innervates diaphragm)
central chemoreceptor
neurons in medullary reticular formation
detects changes in both CO2 and H+ concentration by monitoring H+ levels in cerebrospinal fluid
central chemoreceptor function
-relay info to DRG which alerts VRG
peripheral chemoreceptors
specialized cells in carotid arteries and aorta (called carotid bodies & aortic bodies)
peripheral chemoreceptors function
detects when arterial PO2 falls below 70 mm Hg (normal 100 mm Hg)
chemorecptors send signals to DRG along glossopharangeal (CN IX) and vagus (CN X)
