Chapter 23 - The Respiratory System - Part 3 Flashcards
The general term “respiration” includes 2 integrated processes:
external respiration
internal respiration
external respiration includes…
all of the processes involved in the exchange of oxygen and carbon dioxide between the body’s interstitial fluids and the external environment
what is the PRIMARY FUNCTION of the respiratory system? (both internal and external respiration)
to meet the respiratory demands of cells
What is INTERNAL respiration?
the absorption of oxygen and the release of carbon dioxide by those cells (whose respiratory demands we aim to meet_
NAME THE 3 INTEGRATED STEPS IN EXTERNAL RESPIRATION
- Pulmonary ventilation (breathing) which physically moves air into and out of the lungs
- Gas diffusion across the respiratory membrane between alveolar air spaces and alveolar capillaries and across capillary walls between blood and other tissues
- Transport of oxygen and carbon dioxide between alveolar capillaries and capillary beds in other tissues
What will happen if there are abnormalities in any of these 3 steps of external respiration?
it could ultimately affect the concentration of gases in interstitial fluids, and thus cellular activities as well
What will result if oxygen level declines and the tissues are starved for oxygen?
hypoxia
What results if the oxygen supply is cut off completely to the tissues?
ANOXIA - kills cells very quickly
The damage due to local anoxia could lead to…
strokes and heart attacks
Define external respiration and internal respiration
external respiration - all of the processes involved in the exchange of carbon dioxide and oxygen between the body’s interstitial fluids and the external environment
internal respiration - the absorption of oxygen and the release of carbon dioxide by the body’s cells
Name the integrated steps involved in external respiration
- Pulmonary ventilation (breathing)
- diffusion of gases
- Transport of oxygen and carbon dioxide
What is the PRIMARY FUNCTION of pulmonary ventilation (breathing)
to maintain adequate alveolar ventilation (movement of air into and out of the alveoli)
Alveolar ventilation prevents…
the buildup of carbon dioxide in the alveoli
Alveolar ventilation ensures….
a continuous supply of oxygen that keeps pace with absorption by the bloodstream
Name one of the most basic principles that governs the movement of air
the weight of earth’s atmosphere compresses our bodies and everything around us (atmospheric pressure)
Explain how the concept of atmospheric pressure plays a very important physiological role
air moves into and out of the respiratory system as the air pressure in the lungs cycles between below atmospheric pressure and above atmospheric pressure
how does the cardiovascular system assist the respiratory system?
by transporting gases
What is Boyle’s law?
For a gas that is in a closed container and at a constant temperature…..
PRESSURE IS INVERSELY PROPORTIONAL TO VOLUME
if you double the external pressure on a flexible container, what will happen to its volume?
it will drop by half (1/2)
Name the equation for Boyle’s law
P=1/v
The greater the number of collisions between gas particles, the ____ the pressure
greater
Air tends to flow between areas of ___ pressure to ____ pressure
from high pressure to low pressure
____ + _____ provides the basis for pulmonary ventilation
Boyle’s law + the tendency for directed airflow
a single respiratory cycle consists of….
an inhalation (inspiration) and an exhalation (expiration)
inhalation and exhalation involve changes in ______ of the lungs
volume
These volume changes in the lungs create……
pressure gradients that move air into or out of the respiratory tract
the surface of each lung sticks to…..
the inner wall of the chest and to the superior surface of the diaphragm
Movements of the diaphragm or rib cage that change the volume of the thoracic cavity also changes….
the volume of the lungs
the diaphragm forms the ____ of the thoracic cavity
floor
The relaxed diaphragm has the shape of a _______
dome that projects superiorly into the thoracic cavity
When the diaphragm contracts, what happens to it?
it tenses and moves inferiorly
When the diaphragm contracts, explain what happens to the thoracic cavity
the VOLUME INCREASES so the PRESSURE DECREASES
Explain what happens when the thoracic cavity enlarges when we are taking a breath
When the thoracic cavity enlarges, the lungs expand to fill the additional space. This increase in volume LOWERS THE PRESSURE inside the lungs. Then, air enters the respiratory passageways because the pressure inside the lungs is lower than the atmospheric pressure.
Air continues to enter the lungs until their volume stops increasing and the pressure inside is the same as outside
Explain what happens when the thoracic cavity decreases in volume
the pressure inside the thoracic cavity increases, forcing air out of the respiratory tract
what does the “compliance” of lungs mean?
how easily the lungs can expand (expandability)
The greater the compliance, the ______ it is to fill the lungs
easier
name 3 factors affecting compliance of the lungs
-the connective tissue of the lungs
-the level of surfactant production
-the mobility of the thoracic cage
“the connective tissue of the lungs affects compliance”
explain this statement
the loss of supporting tissues due to alveolar damage (as in emphysema), increases compliance
“The level of surfactant production affects compliance”
explain this statement
the alveoli could collapse upon exhalation if not enough surfactant is produced. This REDUCES compliance
“The mobility of the thoracic cage affects compliance”
explain this statement
arthritis or other skeletal disorders that affect the articulations of the ribs or spinal column REDUCES COMPLIANCE
If compliance of a person’s lungs is significantly reduced, what could happen to them?
they may become exhausted by simply continuing to breathe
What is the most common method of reporting blood pressure and gas pressure?
millimeters (mm) of mercury (Hg)
the direction of airflow is determined by the relationship between _____ pressure and _____ pressure
intrapulmonary pressure (or called intraalveolar pressure) and atmospheric pressure
what is meant by intra-alveolar/intrapulmonary pressure?
the pressure inside the respiratory tract (at the alveoli)
When we are relaxed and breathing quietly, what can you say about the relationship between the atmospheric and intrapulmonary pressure?
the difference is relatively small
when we breathe in, does the intrapulmonary pressure increase or decrease?
decreases to 759mmHg (1 mmHg below atmospheric pressure)
what is the value for atmospheric pressure?
760 mmHg
on exhalation, what happens to the intrapulmonary pressure?
it increases to 761mmHg, so air is forced out
Why are we told to exhale when we’re lifting weights?
exhaling keeps your intrapulmonary pressure from climbing so high that an alveolar rupture or hernia could occur
what is “intrapleural” pressure?
the pressure in the pleural cavity, between the parietal and visceral pleurae
intrapleural pressure averages about…..
-4mmHg
(during a powerful inhalation it could reach -18mmHg)
Why is it not possible for the elastic fibers of the lungs to not recoil completely?
they are not strong enough to overcome the fluid bond between the parietal and visceral pleurae
the intrapleural pressure is always _____ atmospheric pressure during normal inhalation and exhalation due to….
intrapleural pressure is always below atmospheric pressure due to the elastic fibers always remaining stretched even after a full exhalation
the cyclical changes in the intrapleural pressure create the ________
RESPIRATORY PUMP which assists venous return to the heart
What is the respiratory cycle?
a single cycle of inhalation and exhalation
what is meant by the “tidal volume”?
the amount of air you move into or out of your lungs during a single respiratory cycle
inhalation begins with the fall of ___ pressure that takes place when the thoracic cavity expands
intrapleural pressure
tidal volume=
the amount of air moved into the lungs during inhalation = the amount moved out of the lungs during exhalation
name the muscles used in inhalation
-the diaphragm
-the intercostal muscles
-accessory muscles
State which is an active process and which is a passive process (inhalation and exhalation)
inhalation - active process
exhalation - could be passive or active depending on the level of respiratory activity
Respiratory movements are usually classified as ___ or ___
quiet breathing or forced breathing (depending on the pattern of muscle activity during a single respiratory cycle)
a term for “quiet breathing”
eupnea
diaphragmatic breathing is also called…
deep breathing
in quiet breathing (eupnea) explain the contractions necessary for inhalation
contraction of the diaphragm and the external intercostal muscles
During diaphragmatic (deep) breathing, explain the contractions necessary for inhalation
the contraction of the diaphragm alone provides the necessary change in thoracic volume
another word for “costal breathing”
shallow breathing
in costal breathing, inhalation takes place when…
the contractions of the external intercostal muscles raise the ribs and enlarge the thoracic cavity
What type of breathing predominates when abdominal pressures, fluids, or masses restrict diaphragmatic movement?
costal breathing
give an example of an individual who would rely on costal breathing
pregnant women rely more and more on costal breathing as the enlarging uterus pushes the abdominal organs against the diaphragm
forced breathing is also called…
hyperpnea
forced breathing involves what kind of inhalation and exhalation?
BOTH ARE ACTIVE
When would the respiratory system adapt itself?
to meet the oxygen demands of the body. it can do this by varying the number of breaths per minute and the amount of air moved per breath
What is the “respiratory rate”
the number of breaths you take each minute
what is the normal respiratory rate for a resting adult?
12-18 breaths per minute
what is the “respiratory minute volume?”
the amount of air moved each minute (symbolized as VE)
How can we calculate respiratory minute volume?
VE=f*Vr
VE= breaths per minute * tidal volume
Spirometry values are useful in diagnosing problems with….
pulmonary ventilation (breathing)
WHY are there sex related differences in respiratory volumes and capacities?
because females generally have smaller bodies than males, and thus smaller lung volumes
Define compliance and identify factors that affect it
Compliance is the ease with which lungs expand
1. the connective tissue structure of the lungs
2. the level of surfactant production
3. the mobility of the thoracic cage
Name the various measurable pulmonary VOLUMES
resting tidal volume (Vr)
expiratory reserve volume (ERV)
inspiratory reserve volume (IRV)
Mark breaks a rib that punctures the chest wall on his left side. What do you expect will happen to his left lung as a result?
Atmospheric air enters his thoracic cavity (a condition called pneumothorax), raising the pressure within the pleural cavity. As a result, the natural elasticity of the lung may cause the lung to collapse, a condition called atelectasis)
In pneumonia, fluid accumulates in the alveoli of the lungs. How would this accumulation affect vital capacity?
Because the fluid produced in pneumonia takes up space that would normally be occupied by air, vital capacity would decrease
Pulmonary ventilation ensures that….
your alveoli are supplied with oxygen and that carbon dioxide arriving from your blood stream is removed
explain how the actual process of gas exchange takes place
takes place between blood and alveolar air across the respiratory membrane
gases are exchanged between the alveolar air and the bloodstream through…..
DIFFUSION which takes place in response to concentration gradients
Nitrogen accounts for about ____% of atmospheric gas molecules
oxygen ___%
nitrogen = 78.6%
oxygen= 20.9%
remaining 0.5% = water molecules/co2
What is Dalton’s law?
each of the gases in the air contribute to the total pressure in proportion to its relative abundance
what is the “partial pressure” of a gas?
the pressure contributed by a single gas in a mixture of gases
What is Henry’s law?
At a given temperature, the amount of a particular gas in solution is directly proportional to the partial pressure of that gas
Give an every day example of Henry’s law in action
opening a can of soda
when we open the can, the pressure falls and the gas molecules (co2) begin coming out of the solution.
the volume in the can is so small and the volume of the atmosphere is so great that all of the CO2 will comes out of the solution within half an hour and we’re left with flat soda
rank:
Carbon dioxide
Nitrogen
Oxygen
based on their solubility in our body fluids
most soluble=carbon
oxygen
least soluble=nitrogen
Alveolar air contains ___ carbon dioxide and ___ oxygen than atmospheric air
more carbon dioxide and less oxygen
Give 5 reasons why gas exchange at the respiratory membrane is efficient
- The differences in partial pressure across the respiratory membrane are substantial
- The distances involved in gas exchange are short
- The gases are lipid soluble
- The total surface area is large
- Blood flow and airflow are coordinated
What solves the problem of the limited solubilities of oxygen and carbon dioxide in blood plasma?
red blood cells. They remove dissolved o2 and co2 from plasma and bind them (in the case of o2) or use them to manufacture soluble compounds (in the case of co2)
The transport of oxygen and carbon dioxide in blood involves reactions that are completely _____
reversible
What are the 2 ways that the body has to transport oxygen?
only1.5% is oxygen molecules in solution
the rest of the oxygen molecules are bound to hemoglobin molecules
the hemoglobin molecule consists of…
4 globular protein subunits, each containing a heme unit
the oxygen molecules bind to the ____ in the center of heme units
iron ions
EACH hemoglobin molecule can bind ____ molecules of oxygen
4
give the equation for the reversible reaction of oxygen binding hemoglobin
Hb+O2 <-> HbO2
The reversible reaction of oxygen binding hemoglobin allows hemoglobin to…
pick up oxygen in the lungs and release it to other body tissues elsewhere
Each red blood cell can potentially carry how many molecules of oxygen?
more than a billion
What is the “hemoglobin saturation”
the percentage of heme units containing bound oxygen at any given moment
if all the Hb molecules in the blood are fully loaded with oxygen, saturation is…
100%
if each hemoglobin molecule carries 2 molecules on average, hemoglobin saturation is…
50%
What are the 4 most important environmental factors affecting hemoglobin?
- The PO2 of blood
- Blood pH
- Temperature
- ongoing metabolic activity within red blood cells
- 2,3-bisphosphoglycerate (BPG)
if the PO2 of the surrounding plasma increases, will hemoglobin bind oxygen?
yes
if the Po2 of the surrounding plasma decreases, hemoglobin will…
release oxygen
What is the name of the graph that relates the hemoglobin saturation to the partial pressure of oxygen?
oxygen-hemoglobin saturation curve
at equilibrium, oxygen molecules bind to heme at the same rate that……
other oxygen molecules are being released
if the PO2 increases, will the reversible reaction shift to the right or left?
to the right
why is the oxygen-hemoglobin saturation curve a curve rather than a straight line?
because when oxygen binds to hemoglobin, hemoglobin changes shape and makes it easier for hemoglobin to bind to the NEXT oxygen molecule
the characteristic curve of the oxygen-hemoglobin saturation curve assists in what?
we would not be able to survive at high altitudes without the ability of hemoglobin to change shape and make it easier to bind future oxygen molecules
if the pH decreases (assume PO2 IS CONSTANT), hemoglobin will ____ additional oxygen
release
as pH drops, the oxygen-hemoglobin saturation _____
declines
the effect of pH on the hemoglobin saturation curve is called the….
Bohr effect
what is the primary compound responsible for the Bohr effect?
CO2
When CO2 diffuses into the blood, it rapidly does what?
diffuses into red blood cells.
There, the enzyme carbonic anhydrase catalyzes the reaction of CO2 with water molecules, forming carbonic acid
the rate of carbonic acid formed depends on…
the amount of carbon dioxide in solution
When the PCO2 increases, what happens to the acidity of the plasma
it decreases (becomes more acidic)
this is so because the hydrogen ions formed the reaction of CO2 with water forms a bicarbonate ion and a free hydrogen ion. The hydrogen ions generated diffuse out of the RBCs and the pH of the plasma drops
hemoglobin releases ___ oxygen as the temperature increases
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