chapter 22 Flashcards
part 2
daltons law of partial pressures
the total pressure of a gas mixture = the sum of the pressures of each individual gas
total atomospheric pressure
the sum of pressures of the different gases that make up the air we breathe
nitrogen and oxygen
79% and 20.9% make up 99% of Patm
partial pressure
the pressure of each individual gas in the mixture
partial pressure of one gas
is independent of the partial pressure of another gas
henrys law
a gas will dissolve in a liquid in proportion to its partial pressure
higher PP
more gas dissolves
gases dissolve best in liquid under
high pressure
low temperature
high solubility
3 factors affecting rate at which gas exchange occurs between the alveoli and capillaries
- partial pressure gradients and gas solubility
- thickness and surface area of respiratory membranes
- ventilation perfusion coupling
partial pressure gradients and gas solubility
PO2 in alveoli> PO2 in caplliaries
O2 moves from alveoli into blood
PCO2 in capillaries> PCO2 in alveoli
CO2 moves from blood into alveoli
thickness and surface area of respiratory membranes
respiratory membrane is thin: gas exchange occurs quickly
The greater the surface area = the greater amount of gas that can diffuse in a given amount of time
perfusion
flow of blood through blood vessels
composition of alveolar gases
CO2 and water vapors
why is this the comp of alveolar gases
- gas exchange is occurring in the alveoli CO2 into alveoli and O2 into blood
- Conducting passageways humidify air: creates water vapor
- mixture of air in alveoli
internal respiration
gas exchange occurring in tissues
PCO2 in tissues> PCO2 in blood
CO2 moves into blood
PO2 in blood> PO2 in tissues
O2 moves into tissues
carbon dioxide transport
- dissolved in plasma
- binds to amino acids of globulin in hemoglobin
- as bicarbonate ions in plasma
increase in CO2 in blood causes blood ph
to decrease
respiratory acidosis
slow shallow breathing
decrease in CO2 in the blood causes blood ph
to increase
respiratory alkalosis
rapid deep breathing
conversion of CO2 to bicarbonate causes
release of H+ ions
decreases blood pH
buffered by RBC to maintain blood pH at 7.35-7.45
medullary respiratory center
two areas that set the normal respiratory rhythm
ventral respiratory group
dorsal respiratory group
pontine respiratory center
interacts with medullary respiratory center to smooth the respiratory pattern
transition from inhalation to exhalation
CNS measure two factors to determine breathing rate and depth
- CO2 levels
- O2 levels in arterial blood
hypercapnia
increase CO2 in the blood
causes decrease in blood pH
increase breathing rate and depth to let more CO2 out
hypocapnia
decrease in CO2 in blood
causes increase in blood pH
decrease breathing rate/depth to hold onto more CO2
higher brain center influence on respiratory rate
- hypothalamic controls: strong emotion and pain send information from hypothalamus/limbic system to the respiratory centers
- cortical controls: we can override the respiratory centers to control our own breathing/depth
chronic obstructive pulmonary disorder
group of conditions characterized by a physiological inability to expel air from the lungs
labored breathing, coughing, pulmonary infection
irreversible
emphysema COPD
permanent enlargement of the alveoli and eventual destruction of their walls
bronchioles collapse during expiration: trap air in alveoli
chronic bronchitis COPD
Chronic production of excess mucous due to inhaled irritants
mucous not removed: bacteria and microorganisms thrive in stagnant mucous so infection is frequent
Asthma
temporary bronchospasm attacks followed by a period of symptom-free
treatment: inhaled corticosteroids and/or bronchodilators
tuberculosis
bacterial disease spread through inhaled air
33% of world is infected but not active
sleep apnea
temporary cessation of breathing while sleeping
must wake up during sleeping to resume breathing
obstructive sleep apnea
upper airways collapse during sleep
most common in men
CPAP machines: constantly blow air into passages to prevent collapse
central sleep apnea
respiratory centers of brain slack during sleep: breathing rhythm/rate not maintained
