Definitions
What is pulmonary ventilation?
movement of air into & out of the lungs
Where does gas diffusion take place?
Gas diffusion takes place between capillaries & alveoli.
What muscle controls inspiration at rest?
Diaphragm
Describe Boyle's Law.
describes how pressure of a gas tends to increase as the volume of the container decreases
List 3 factors that shift the ODC
temperature, acidity (CO2 and H+), 2,3 DPG
Where is the respiratory control center?
medulla oblongata
Movement of blood containing gases
Gas transport
What are the main four functions once air passes through the respiratory tract?
conducts air, warms air, humidifies air, filters air
Between breaths, intrapulmonary & atmospheric pressure are_______.
Equal
Each gas moves according to its own individual pressure refers to ....
Dalton's Law
Differences between PO2 in alveoli & blood (______ mm Hg) and between blood & tissue (_____ mm Hg) provide driving force for diffusion of oxygen
65, 60
Explain the humoral chemoreceptors?
Central chemoreceptors -- Located in the medulla, PCO2 and H+ concentration in cerebrospinal fluid
Peripheral chemoreceptors -- Aortic and carotid bodies, PO2, PCO2, H+ in blood
Movement of gases from an area of high to low concentration
pulmonary diffusion
What is the purpose of the pleural fluid?
Pleural fluid creates intrapleural (intrathoracic) pressure which allows lungs to stick to surface of thoracic cavity & diaphragm
List the 4 accessory expiratory muscles
internal intercostals
rectus abdominis
internal oblique muscles
transverse abdominis
Total pressure of gas mixture = sum of partial pressures of each gas is which law?
Dalton's
What are the functions of myoglobin?
Assists in passive diffusion of O2
Functions as O2 reserve at start of exercise
100% saturated at lower PO2 than hemoglobin
Binds just one oxygen
What are the neural inputs?
From motor cortex
Skeletal muscle (mechanoreceptors, joint receptors)
Lung receptors (stretch, irritant)
What is tidal volume?
Amount of air entering and leaving the lungs per breath
How can airflow be increase?
Amplifying pressure difference between 2 areas
Decreasing resistance to airflow
List the 4 accessory inspiratory muscles.
external intercostals
scalenes
sternocleidomastoid
pectoralis minor
amount of gas dissolved in any fluid depends on…
•temperature
•solubility of gas
•partial pressure (PP) of gas
Three ways and percentages in which CO2 is transported?
7-10% is dissolved in plasma
20% is bound to hemoglobin
70% is transported as bicarbonate
Describe ventilatory threshold.
•point at which body switches from aerobic to anaerobic respiration
•Once intensity increases to point where aerobic metabolism can no longer keep up with energy demands, switches to anaerobic metabolism
vital capacity
What happens to depth and rate of breathing during exercise?
·Increase in depth (VT) of breathing occurs first at the onset of exercise
·Increase in rate (f) of breathing is secondary
What is the difference between inspiration and expiration?
•During inspiration: increased lung volume, Increase in volume of intrathoracic cavity, Decreases intrapulmonary pressure
•During expiration: decreased lung volume, Decrease in volume of intrathoracic cavity, Increases intrapulmonary pressure
The volume of gas the diffuses is proportional to (Fick's Law)
•A = surface area available for diffusion
•D = diffusion coefficient of gas
•T = thickness of membrane
•P1- P2 = difference in PP of gases
Describe PO2 at the lungs vs. in the tissues.
•High PO2 at lungs -- Hemoglobin ~100% saturated with O2. Even if PO2 decreases slightly at lungs, the ODC still allows full saturation
•Low PO2 at tissues -- O2 released from hemoglobin and delivered to tissues
REST: PO2 at tissues is ~40 mm Hg, so 25% of O2 is released from hemoglobin
EXERCISE: PO2 at tissues decreases, 90% of O2 is released
What is the ventilatory equivalent for O2?
V•E/V•O2 (L air breathed/L O2 consumed/min) -- 26 L
Index of how well control of breathing is matched to body’s demand for oxygen