Chapter 23: Respiratory System Flashcards
respiration
gas exchange: O2 and CO2
pulmonary ventilation
movement of gases between atmosphere and alveoli
pulmonary/alveolar gas exchange
exchange of gases between alveoli and blood
- occurs at the respiratory membrane
gas transport
transport of gases in blood between lungs and systematic cells; handling of the gases in the bloodstream
tissue gas exchange
exchange of respiratory gases between the blood and the systematic cells
muscles of quiet breathing (eupnea)
increase dimensions of the thoracic cavity
- diaphragm
muscles of forced inspiration (hyperpnea)
pull upward and outward
- sternocleidomastoid
- scalenes
- erector spinae
muscles of forced expiration
pull downward and inward
- external oblique
inspiration
inhale
expiration
exhale
when the diaphragm contracts
it flattens and drops the thoracic cavity
when the diaphragm relaxes
it goes back to its concave shape
Boyle’s gas law: relationship of volume and pressure
inverse relationship between gas pressure and volume
pulmonary ventilation
- the net movement of O2 from the atmosphere to alveoli during inspiration
- net movement of CO2 from alveoli to atmosphere during expiration
pulmonary/alveolar gas exchange
- O2 diffuses from alveoli into blood
- CO2 diffuses from blood to alveoli
gas transport
- O2 is transported from the lungs to systematic cells
- CO2 is transported from systematic cells to lungs
tissue gas exchange
- O2 diffuses from blood into systematic cells
- CO2 diffuses from systematic cells into blood
intrapleural pressure
the pressure of the fluid around your lungs
intrapulmonary pressure
the air pressure inside the lungs
- lungs experience an outward pull
atmospheric air pressure
air pressure outside the body
- usually around 760 mmHg
medullary respiratory center
- controls contraction of the diaphragm via phrenic nerve
- controls contraction of external intercostals via intercostal nerves
pontine respiratory center
- modifies the activity of the nuclei in the medulla
- provides a smooth transition between inspiration and expiration
- erratic breathing results if area is damaged
apnea
absence of breathing
sleep apnea
temporary cessation of breathing during sleep
eupnea
quiet breathing = 12-15 breaths/min
reflexes respond to sensory input from receptors:
- chemoreceptors
- proprioceptors
- baroreceptors
- irritant receptors
chemoreceptors
monitor changes in concentrations of H+, PCO2, and PO2
chemoreceptors are located in
CSF, carotid bodies, and aortic bodies
chemoreceptors stimulate
medullary respiratory center
reflexes that alter breathing rate and depth
action of higher brain centers
- hypothalamus increases breathing rate if body is warm
- limbic system alters breathing rate in response to emotions
- The frontal lobe of the cerebral cortex controls voluntary changes in breathing patterns
airflow
amount of air moving in and out of the lungs with each breath
F=△P/R
F= flow
△P= difference in pressure between the atmosphere and intrapulmonary pressure
R= resistance
airflow depends on
- the pressure gradient established established between atmospheric pressure and intrapulmonary pressure
- the resistance that occurs due to conditions within the airways, lungs, and chest wall
baroreceptors are located
within visceral pleura and bronchiole smooth muscle
baroreceptors are stimulated by
stretch
baroreceptors initiate
the inhalation reflex
proprioceptors are located
within joints and muscles
proprioceptors stimulated
by body movement
pressure gradient
difference between atmospheric pressure and intrapulmonary pressure
resistance
factors that increase difficulty moving air
resistance may be altered by three things
1) change in the elasticity of chest walls and lungs
2) change in bronchiole diameter
3) collapse of alveoli
surfactant
keep alveoli open
surfactant breaks
water tension
air flow is directly related to __________________ and inversely related to ____________
pressure gradient/resistance
compliance
- ease with which lungs and chest wall expand
- the easier the lungs expands, the greater the compliance
more forceful inspirations of respiratory disorders require high
amounts of energy
minute ventilation/pulmonary ventilation (PV)
air moved b/w atmosphere and alveoli in 1 minute
tidal volume (TV)
amount of air/breath
respiration rate (RR)
of breaths/minute
formula for pulmonary ventilation
TVxRR=PV
average amount of air that is handled by your lungs every time you breath in and out
500 mL
average breaths per minute
12 breaths/min
anatomic dead space
air remaining in conducting zone which has no contact with alveoli for gas exchange
alveolar ventilation
actual air exposed to alveoli
- less than PV
formula to find AV
(TV - anatomic dead space) x RR = AV
(500mL - 150mL) x 12 = 4.2 L/min
spirometer
measures respiratory volume
tidal volume
amount of air inhaled or exhaled per breath during quiet breathing
inspiratory reserve volume (IRV)
amount of air that can be forcibly inhaled beyond tidal volume
- measure of compliance
expiratory reserve volume (ERV)
amount of air that can be forcibly exhaled beyond tidal volume
- measure of elasticity
residual volume
amount of air left in the lungs after the most forceful expiration
vital capacity
maximum amount of air that can be forcefully expired after a forced inspiration
partial pressure
pressure exerted by EACH gas within a mixture of gases (measured in mm Hg)
- written P with gas symbol (i.e., PCO2)
Dalton’s law says,
each gas moves independently down its own partial pressure gradient during gas exchange
Atm pressure =
760 mm Hg (sea level)
Dalton’s law
the total pressure in a mixture of gases is equal to the sum of the individual partial pressures
at the resp. membrane
- O2 goes from alveolus to blood
- Co2 goes from blood to alveolus
at systemic cells/tissues of the body
- O2 goes from the blood to the systematic tissues
- CO2 goes from the tissues to the blood
Henry’s law
the solubility of a gas in a liquid is dependent upon:
- partial pressure of the gas in the air
- solubility coefficient of the gas in the liquid
Henry’s partial pressure
driving force moving gas into liquid
solubility coefficient
volume of gas that dissolves in a specified volume of liquid at a given temperature and pressure
gases vary in their solubility in water
- CO2 about 24 times as soluble as O2
- N2 about half as soluble as oxygen
least to most soluble gases
- N2
- O2
- CO2
decompression sickness
diver submerges in water beyond a certain depth, returns quickly to the surface
- N2 forced into blood due to the higher pressure (deep ocean)
fast ascent… dissolved N2 bubbles
pop out of solution while still in blood and tissues
decompression sickness is treated with
hyperbaric O2 chamber
anatomical features of membrane contributing to efficiency
- large surface area (70 square meters)
- minimal thickness (0.5 micrometers)
blood’s transport of O2 depends on
- solubility coefficient of O2
- the iron of hemoglobin attaches to hemoglobin
about ___% of O2 in blood is bound to hemoglobin
98
oxyhemoglobin
with bound oxygen
deoxyhemoglobin
without bound oxygen
CO2 has 3 means of transport in the blood:
1- CO2 dissolved in plasma (7%)
2- CO2 directly attached to Hb (23%)
3- converted to bicarbonate (HCO3-), dissolved in blood plasma (70%)
HCO3-
bicarbonate (working form of carbon dioxide)
conversion of CO2 to HCO3- at systematic capillaries
1- CO2 movement into erythrocyte
2- formation of HCO3- and H+
3- HCO3- leaves the erythrocyte while Cl- goes into the erythrocyte (chloride shift)
formation of HCO3- and H+
- CO2 is joined to H2O to form carbonic acid (H2CO3) by carbonic anhydrase
- H2CO3 splits into bicarbonate and hydrogen ion
conversion of HCO3- to CO2 at pulmonary capillaries
1- chloride movement as Cl- moves out
2- formation of CO2 and H2O
3- CO2 movement out of the erythrocyte into an alveolus
formation of CO2 and H2O
- HCO3- recombines with H+ to form H2CO3
- H2CO3 dissociates into CO2 and H2O
oxygen-hemoglobin saturation curve
- saturation increases as PO2 increases
- graphed in the oxygen-hemoglobin curve
you get the right shift of the hemoglobin saturation curve when you
drop the pH
when your body becomes acidic, hemoglobin releases
oxygen
you get a right shift of the hemoglobin saturation curve when the body is
warm
a right shift occurs when hemoglobin is
releasing oxygen
hyperventilation
breathing rate or depth above the body’s demand
hypoventilation
breathing too slow (bradypnea) or too shallow (hypopnea)
hyperventilation causes _____________ which can result in ______________________
hypocapnia/ respiratory alkalosis
respiratory alkalosis
pH will start to get really high in the blood stream
hypoventilation causes ___________ which can result in ____________________
hypercapnia/ respiratory acidosis
