Exam 2 Flashcards
What is surfactant?
Active Surface Agent produced by the alveoli.
What does surfactant do?
Reduces surface tension in the alveoli allowing them to stay open
Definition of Perfusion
movement of oxygen to and into the cells
Definition of Diffusion
movement of oxygen across alveolar walls into pulmonary capillaries
Where is pulmonary interstitium located?
Between alveoli and capillary
What does the pulmonary capillaries of alveolar(capillary membrane) do?
form a network around each alveolus so dense that an almost continuous sheet of blood covers the alveoli.
lungs are covered by what?
double layered membrane called pleura
visceral pleura is attached to
lungs
parietal pleura is attached to
chest wall cavity
How large is each capillary?
Interior diameter of each capillary is just large enough to allow red blood cells to squeeze by in single file so that their cell membranes touch the capillary walls
CO2 and O2 do not pass through plasma when
diffusing in and out of the alveoli
Each RBC stays in the pulmonary capillary bed for about how long?
1 second
Each RBC exchanges gases with how many alveoli per second.
2-3 alveoli
What does surfactant do?
lowers surface tension of alveolar walls, increases lung compliance(elasticity), and eases the work of breathing
How often must surfactant be replenished?
continuously
What stimulates surfactant replacement?
normal ventilation
Hypoventilation leads to what?
decreased surfactant/alveolar collapse/atelectasis
What does a normal unit look like: alveoli/capillary
Normal ventilation, normal perfusion
What does a dead space unit look like?
Normal ventilation, no perfusion
What does Shunt unit look like?
No ventilation, normal perfusion
What does a silent unit look like
No ventilation, no perfusion
pulmonary embolism is an example of what kind of space
Dead space unit
How many oxygen molecules can one RBC carry?
1200
If any of the 7 steps of oxygenation get interrupted, what happens?
tissue becomes hypoxic (low oxygen levels)
What is hypoxemia?
decreased oxygenation of arterial blood
What is Hypoxia?
decreased oxygenation of the cell
List the seven steps required to transfer oxygen from environmental air into the lungs
- Ventilation
- Transport of O2 from alveoli into plasma and red blood cells
- Reversible chemical combination of O2 and CO2 with Hemoglobin(HGB)
- Circulation of blood from pulmonary venous capillaries to systemic capillaries
- Diffusion of O2from capillary blood into interstitial fluid
- Diffusion into cells
- Diffusion of O2 into mitochondria where(in combination of glucose) it helps synthesize ATP
Definition of oxygenation:
steps required to transfer O2 from environmental air into cells
Explain step one of oxygenation
ventilation of lungs-brings O2 to alveolar capillary membrane(exchange surface)
Explain step two of oxygenation
Transport of O2 from alveoli into plasma and RBCs-one RBC contains 300 HGB, Each HGB molecule can carry 4 O2 molecules, so each RBC can carry 1200 O2 molecules
Explain step three of oxygenation
Reversible chemical combination of O2 and CO2 with HGB (this is due to pressure changes)
Explain step four of oxygenation:
circulation of blood from pulmonary venous capillaries to systemic capillaries
Explain step 5 of oxygenation
Diffusion of O2 from capillary blood into interstitial fluid
Step 6 of oxygenation
Diffusion into cells
Step 7 of oxygenation
Diffusion of O2 into mitochondria where(in combination with glucose) it helps to synthesize ATP
Etiologies of hypoxia include:
- reduced transfer of O2 from alveolar(atmospheric) air to blood(hypoxemia)
- Impaired transport of O2 across alveolar membrane
- ventilation/perfusion mismatch
- decreased HGB concentration
- decreased inspired oxygen
- Ischemia
One cause of hypoxia is reduced transfer of O2 to blood, an example of this is hypoventilation, define and give some causes of hypoventilation
Hypoventilation is decreased rate and/or decreased depth of respirations. Some causes of hypoventilation include drug overdose, anesthesia, chest or abdominal pain, surgery, and trauma
Another cause of Hypoxia is impaired transport of O2 across the alveolar membrane. This diffusion capacity of alveolar membrane can be affected by what three things?
- Whether surface area is available or not
- the thickness of the membrane
- interstitial space issues
Another cause/etiology of hypoxia is ventilation/perfusion mismatch. Explain this
Ventilation or (air into alveoli) and perfusion (pulmonary capillary blood flow) are mismatched. They should match well normally. Being mismatched causes dead space unit or shunt space unit or silent space unit.
Another etiology of hypoxia is Low HGB concentration also known as Anemia. Causes of anemia include:
blood loss, decreased production of RBCs, and decreased iron intake
Carbon monoxide(CO) poisoning can also cause Hypoxia by decreasing Hemoglobin production, explain CO poisoning:
CO combines with HGB at same site as O2
*Hemaglobin is 210x more likely to go for CO molecule that for an O2 molecule. (HGB has an affinity for CO.)
Another etiology of hypoxia is decreased inspired oxygen. Two examples of this include:
- breathing high altitude air (in the mountains, there is not as much O2 in the air.
- breathing air from which O2 has been removed.
Breathing air while on vacation in the rocky mountains could cause you to become:
Hypoxic
Being trapped in a building where there is a fire and inspiring low O2 concentrated air can cause you to become what?
Hypoxic
Two causes of low hemoglobin concentration are what?
anemia and CO poisoning
What happens during CO poisoning
CO combines with Hemoglobin at the same site as Oxygen does.
If you have Carbon monoxide in your home this may cause you to become what?
Hypoxic
If you lose a lot of blood, you may become what?
Anemic/Hypoxic
If your production of red blood cells decreases your hemoglobin level will decline and you may become?
Hypoxic
You must get enough iron in your diet so you do not become anemic in order to prevent what?
Low Hemoglobin levels that can lead to hypoxia
What is Ischemia?
Ischemia is decreased blood flow to tissues(O2 cannot get to where it is going)
Ischemia can be caused by what three things?
- vasoconstriction
- obstruction in blood vessel(blood clot in artery)
- decreased cardiac output
Ischemia can be either…
local/regional or general/systemic
Local/regional ischemia is
local-something is blocking artery, for example:atherosclerosis of iliac arteries leading to decreased blood flow to the legs.
general/systemic ischemia is
decreased perfusion of O2 to tissues(overall), example: heart failure leading to decreased cardiac output.
two clinical manifestations of Hypoxia include:
Increased pCO2 (percent of Carbon monoxide) and decreased pH (respiratory acidosis)
To assess for Hypoxia, you would check the what?
Arterial blood gases-SaO2, PaO2
SaO2 means
percent of available HGB that is saturated with O2. (95-100) is good.
PaO2 means
partial pressure of O2 in arterial blood
early signs of Hypoxia include:
changes in behavior, levels of consciousness, confusion, lethargy, increased heart rate,
middle signs of Hypoxia include: dyspnea(shortness of breath)
dyspnea(shortness of breath), decreased urine output, prolonged capillary refill
A late sign of hypoxia is:
blue tinted lips, tongue, mucous membranes
Approximately how many alveoli do we have?
300 million
This involves the transfer of gases between air-filled spaces in the lungs and blood?
diffusion
In emphysema patients the urge to breathe is stimulated by what?
decreased oxygen
The two processes that occur during respiration are?
inspiration and expiration
In what area of the lung does respiration occur?
alveoli
What does the hypoxic drive do?
It stimulates a person to breathe on the basis of low oxygen levels.
Dyspnea is most accurately defined as?
shortness of breath or difficulty breathing
A pleural effusion is most accurately described as
fluid accumulation outside the lung
A blood clot lodged in a pulmonary artery is referred to as a
pulmonary embolism
The oxygen-carbon dioxide exchange takes place in the
alveoli
If carbon dioxide levels drops too low, the person automatically breathes:
slower and less deeply
slow/shallow
If the level of carbon dioxide in the arterial blood rises above normal, the patient breathes:
rapidly and deeply
fast/deep
The rate of breathing typically increases when?
carbon dioxide levels increase
Altered mental status is an example of?
Hypoxia to the brain
An obstruction to the exchange of gases between the alveoli and the capillaries may result from:
pneumonia
pulmonary edema can develop quickly after a major
heart attack
pulmonary edema may also be produced by
inhaling toxic chemical fumes
The loss of the elastic material around the air spaces as a result of chronic stretching of the alveoli is
Bronchitis
A patient with COPD usually presents with
a green, yellow, or rusty productive cough
A pneumothorax is a complete accumulation of air in the:
pleural space
A collection of fluid outside the lungs on one or both sides of the chest is called a
pleural effusion
Over breathing to the point that the level of arterial carbon dioxide falls below normal is
hyperventilation
Pulse oximeters measure the percentage of hemoglobin saturated with
oxygen
With a pneumothorax, the lung collapses because
the negative vacuum pressure in the pleura space is lost.
Patients with Carbon monoxide poisoning initially complain of
headache, fatigue, and nausea
Pulmonary edema is commonly associated with
congestive heart failure
COPD most often results from
cigarette smoking
Signs and symptoms of pulmonary emboli include:
dyspnea, hemoptysis, and tachycardia
What passes from blood through capillaries to tissue cells
oxygen
What are the sounds of air trying to pass through fluid in the alveoli
rales or crackles
A patient with a barrel chest and a “puffing” style of breathing most likely has
emphysema
An acute or chronic inflammation of the major lung passageways
bronchitis
accumulation of air in the pleural space
pneumothorax
Fluid build up within the ALVEOLI AND LUNG TISSUE
Pleural effusion
An infection of the lung that damages lung tissue
pneumonia
disease in the lungs in which the alveoli lose elasticity due to chronic stretching
emphysema
fluid outside the lung
pleural effusion
condition in which the body;s cells and tissues do not have enough oxygen
hypoxia
the exchange of oxygen and carbon dioxide
respration
a disease that can lay dormant in the lungs for decades, then reactivate
tuberculosis
movement of O2 to and into the cells is called
perfusion
pulmonary embolism most likely leads to a
dead space unit
surfactant does what in the alveoli?
decreases surface tension of alveolar walls that helps keep alveoli open
CO poisoning leads to
fewer spots for O2 to attach the the heme
two early signs of hypoxia
change in behaviorLOC/ increased HR
two late signs of hypoxia
decreased BP/cyanosis
The pressure in the pleural space is normally:
A bit less than atmospheric pressure
What is the term for “collapse of alveoli”? What to things would you expect to hear for lung sounds?
Atelectasis- crackles/diminished lung sounds
List four labs you might seek out if you were worried about oxygenation…
pO2, pCo2, SaO2, HGB
Pleural effusion includes
- fluid in pleural space
- usually a disease process(fluid, blood,pus)
- pushes on lung tissue
- atelectasis
pneumothorax includes
- air in pleural space
- destroys negative pressure
- lung collapses
- atelectasis to full collapse
Both pneumonia and tuberculosis have a
vaccine
pneumonia and TB both are transmitted via
respiratory droplet route
pneumonia can be caused by any bacteria or virus but TB is specifically caused by
mycobacterium tuberculosis
Tuberculosis facts
infected get a tubercle lesion, can be dormant or active. symptoms are similar of that of pneumonia, but they also consist of night sweats, and a cough that starts out non-productive and ends up productive after a few weeks. Must get CXR
A pulmonary emboli is usually seen in someone at risk for
blood clots
What is the most common etiology of pulmonary edema?
Left ventricular heart failure