Unit 5 - Breathing PART C Flashcards
Gases move DOWN pressure gradients, from areas of ___ pressure to areas of ___ pressure.
HIGH
LOW
(like BF)
Gas pressures in the air and blood are measured in…
mmHg.
ATMOSPHERIC PRESSURE - BP & environmental air pressure in mmHg
The respiratory system creates changes in gas pressure by…
the contraction and relaxation of skeletal muscles that act to increase and decrease the volume of the thoracic cavity (and by extension the volume and pressure of gasses in the lungs).
So we need to understand the relationship between gas volume and gas pressure, which is given in…
Boyle’s Law
Boyle’s Law:
P1V1 = P2V2
Boyle’s Law: P1V1 = P2V2
for a given quantity of gas in an airtight container, the pressure is inversely related to the volume of the container (as volume decreases, pressure increases, and as volume increases, pressure decreases).
Boyle’s Law: P1V1 = P2V2
For example if P1 = 100mmHg of a gas in a 1.0 liter container, how does the pressure change when that same gas is put into a container of 0.5 liters?
(100 mmHg) (1.0L) = (P2) (0.5 L), so P2 = 100 mmHg/0.5L = 200 mmHg/L, which is a higher pressure. This equation demonstrates that decreasing the volume of a gas , increases the pressure of that gas.
Respiratory air flow is similar to ___ in the CV system b/c…
BF
both air & blood are fluids
What is a primary difference b/t respiratory air flow & BF in the CV system?
blood is a NONcompressible liquid but air is a compressible mixture of gases
In the respiratory system, changes in the volume of the chest cavity during ventilation cause…
pressure gradients that create air flow
When chest volume INCREASES, alveolar pressure ____, & air flows ___ the respiratory system
FALLS
INTO
When chest volume DECREASES, alveolar pressure ____, & air flows ___ into the atmosphere
INCREASES
OUT
The movement of air is _____ b/c the ENTIRE gas mixture is moving rather than merely 1 or 2 of the gases in the air
BULK FLOW
The air we breathe is ______, which is composed not only of oxygen, but also nitrogen, carbon dioxide, and trace amounts of other gases like carbon monoxide.
atmospheric air
The air we breathe is atmospheric air, which is composed…
not only of oxygen, but also nitrogen, carbon dioxide, and trace amounts of other gases like carbon monoxide.
When we examine the oxygen and carbon dioxide pressures involved in respiration, we must account for this mixture using…
Dalton’s Law
Dalton’s Law:
Total pressure of a mixture of gases = the sum of the partial pressures (P) that each gas exerts independently. In air with high humidity, this also includes the partial pressure of the water vapor.
The pressure of atmospheric air at sea level is ______. Changes in altitude produce changes in…
760 mmHg
total atmospheric air pressure pressure, as do changes in humidity.
To determine the partial pressure of oxygen in the atmosphere at sea level:
Partial Pressure of a gas = Atmospheric pressure x % of gas in the atmosphere. The percentage of oxygen in the atmosphere is 20.95%., so at sea level, PO2 is 20.95% x 760mmHg = 159.2
Partial Pressure of a gas
pressure of a SINGLE gas in a mixture
- the pressure exerted by an individual gas is determined only by its relative abundance in the mixture & its independent of the molecular size or mass of the gas
Total Pressure =
PN2 + PO2 + PCO2 +PH2O
↑ altitude =
↓ atmospheric PO2
↑ humidity =
↓ atmospheric PO2
When a liquid is exposed to air, gas molecules…
can enter the liquid and dissolve into it until an equilibrium is reached
At equilibrium the…
Pgas in air = Pgas in liquid
At equilibrium the Pgas in air = Pgas in liquid
this is how…
this is how alveolar gas pressures affect the pressure of
gases dissolved in the blood plasma
At equilibrium the Pgas in air = Pgas in liquid
gasses will…
gasses will diffuse down their partial pressure gradients from the alveoli to the blood (O2), or from the blood to the alveoli (CO2) until equilibrium is reached.
Lung Volumes and Capacities
Can be used to determine…
normal/abnormal lung function during a pulmonary function test using a spirometer
Spirometer
an instrument that measures the volume of air moved with each breath
The bulk flow exchange of air b/t the atmosphere & the alveoli is _____, or ______
ventilation
breathing
A single ______ consists of an inspiration by an expiration
respiratory cycle
Tidal volume (TV) =
volume air that moves into OR out of the lungs during one breath (~500 mL at rest). Inspiration = 500 mL, Expiration = 500 mL.
(“Breathe quietly”)
Inspiratory Reserve Volume (IRV) =
maximal volume of air that can be inspired following a normal breath in (so beyond tidal volume).
“Now, at the end of a quiet inspiration, take in as much additional air as you possibly can.”
Expiratory reserve volume (ERV) =
maximal air volume that can be EXPIRED following a normal expiration.
“Now stop at the end of a normal exhalation, then exhale as much air as you possibly can.”
Residual Volume (RV) =
volume of air remaining in lungs following maximal expiration.
(most of it exists b/c the lungs are held stretched against the ribs by the pleural fluid)
Vital Capacity (VC) =
maximal volume of air that can be exchanged per breath (sum of TV + IRV + ERV).
Total Lung Capacity (TLC) =
maximal amount of air that the lungs can hold (sum of TV + IRV + ERV + RV).
Functional residual capacity (FRC) =
amount of air held in the lungs after a tidal expiration (FRC = ERV + RV).
Forced expiratory volume in 1 second (FEV1) =
volume of air expired in 1 second during a forced maximal expiration after taking a maximal inspiration.
Forced expiratory volume in 1 second (FEV1)
Can be compared to…
vital capacity to determine lung function.
Forced expiratory volume in 1 second (FEV1)
Obstructive lung diseases
- make it difficult to expire (shortness of breath)
- have a low FEV1/VC ratio (normally should be ~0.80 or 80%)
- Includes asthma; bronchitis (inflammation of bronchi); emphysema (walls of alveoli are damaged creating fewer larger alveoli); chronic obstructive pulmonary diseases (COPD); etc.
Forced expiratory volume in 1 second (FEV1)
Obstructive lung diseases
Includes
asthma; bronchitis (inflammation of bronchi); emphysema (walls of alveoli are damaged creating fewer larger alveoli); chronic obstructive pulmonary diseases (COPD); etc.
Forced expiratory volume in 1 second (FEV1)
Restrictive diseases
- lungs are restricted from fully expanding.
- show a normal ratio but have reduced values for both FEV1 and VC.
- Includes scoliosis (lateral curvature of the spine in the thoracic region); pneumothorax (lung collapse); pulmonary fibrosis (thickening and scarring of lung); obesity, etc.
Forced expiratory volume in 1 second (FEV1)
Restrictive diseases
Includes
scoliosis (lateral curvature of the spine in the thoracic region); pneumothorax (lung collapse); pulmonary fibrosis (thickening and scarring of lung); obesity, etc.
Breathing is an ____ process that requires…
ACTIVE
MUSCLE CONTRACTION
Breathing is an active process that requires muscle contraction, where…
muscles of the thoracic cage & diaphragm function as the pump b/c most lung tissue is thin exchange epithelium
- when these muscles contract, the lungs expand, held to the inside of the chest wall by the pleural fluid
