respiratory system part 3 Flashcards
what does optimal gas exchange require
coupling of ventilation and perfusion
ventilation-perfusion coupling is the relationship between what
alveolar ventilation and blood flow to alveoli
amount of gas reaching alveoli
ventilation
blood flow in pulmonary capillaries
perfusion
blood not completely ozygenated is what
shunted blood
what is anatomical shunt
due to deoxygenated blood from bronchi-bronchioles mixing with blood in pulmonary veins
what is a physiological shunt
combo of anatomincal shunt and incompletely oxygenated blood from alveoli= 1-2% of cardiac output
when does distripution of ventilation-perfusion coupling occur
it occurs if insuffiecient blood flow to alveoli and if insufficient air flow to alveoli
is less blood flow to alveoli
post MI with inadequate cardiac output
body position
standing=
increased gas exchange in lung bases
if less ventilation to alveoli
pulmonary capillaries not fully oxygenated
pneumonia
pulmonary edema
what is ventilatioin- perfusion coupling controlled by
local autoregulatory mechanisms
PO2= partial pressure of oxygen, amount of oxygen gas dissolved in blood=
controls perfusion via change in arteriole diameter
PCO2 = Partial Pressure of CO2 , Amount of CO2 within Arterial or Venous Blood=
controls ventilation via change in bronchiole diameter
what is used by cells to make atp from glucose
O2
what is Hgb
protein in RBC that transports O2 and CO2 in the blood
what percentage is bound to Hgb within RBC
98.5= 4 oxygen
how much is dissolved in plasma
1.5%
what is formed as a by-product of breakdown of glucose when cells use O2 to produce ATP
CO2
what percentage of CO2 is converted to bicarbonate ion
70%
what percentage of CO2 is bound to Hgb within RBCS
23%
what % of CO2 is dissolved in plasma
7
tight regulation of CO2 in blood is due to what
excessive CO2 leading to acidic blood
CO2 binds to what chains in Hgb
alpha and beta
the smaller the amount of oxygen->
the greater the amount of CO2 that can bind
The smaller the amount of Oxygen the greater the amount of CO2 that can bind
haldane effect
gas exchange in tissues
- In the tissue, CO2 diffuses into the plasma and into the blood cells.
- In the red blood cells, CO2 reacts with water (H2O) to form carbonic acid (H2CO3) in a reaction catalyzed by the enzyme carbonic anhydrase (CA).
- Carbonic acid dissociates to form bicarbonate ions (HCO3−) and hydrogen ions (H+).
- As HCO3− diffuses out of the red blood cells, electrical neutrality is maintained by the diffusion of chloride ions (Cl−) into them.
- Oxygen is released from hemoglobin (Hb). Oxygen diffuses out of red blood cells and plasma into the tissue.
- Hydrogen ions (H+) combine with hemoglobin, which promotes the release of O2 from hemoglobin.
- Carbon dioxide combines with hemoglobin. Hemoglobin that has released O2 readily combines with CO2 (Haldane effect).
gas exchange in the lungs
- In the lungs, CO2 diffuses from red blood cells and plasma into the alveoli.
- Carbonic anhydrase (CA) catalyzes the formation of CO2 and H2O from H2CO3.
- Bicarbonate ions (HCO3−) and H+ combine to replace H2CO3.
- As HCO3− diffuses into red blood cells, electrical neutrality is maintained by the diffusion of chloride ions (Cl–) out of them.
- O2 diffuses into the plasma and into red blood cells. O2 binds to hemoglobin.
- Hydrogen ions (H+) are released from hemoglobin, which promotes the uptake of O2 by hemoglobin.
- CO2 is released from hemoglobin. Hemoglobin that is bound to O2 readily releases CO2 (Haldane effect).
inadequate oxygen delivery to body tissues
hypoxia
how is hypoxia viewed
as a cyanotic hue when Hgb saturation is <75%
where do u see hypoxia
in nails beds and nucosae
different classes of hypoxia
anemic
ischemic
hypoxemic
due to decreased RBCs or abnormal/ decreased Hgb
anemic
due to impaired/ blocked blood circulation
ischemic
due to reduced arterial PO2
abnormal V-Q coupling, pulmonary diseases, air with decreased oxygen
hypoxemic
what is odorless, colorless gas. leading cause of death from fire
carbon monoxide poisoning
in carbon monoxide poisoning the Hgb=
200x greater affinity for CO than oxygen
S&S of carbon monoxide poisoning
confusion
H/A
skin cherry red
Tx for carbon monoxide poisoning
hyperbaric therapy or 100% oxygen until CO cleared from body
true or normal respiratory rate and rhythm
eupnea
Increase in Rate & Depth of Breathing that exceeds the Body’s need to remove CO2. Anxiety Attack. NEVER PRIOR TO SWIM Drown
hyperventilation
= Low CO2 levels in the blood as Blow off CO2 Constriction of Cerebral BV’s Low Brain Perfusion Cerebral Ischemia Dizziness / Faint
hypocapnea
symptoms of hypocapnea
tingling and tetany of face and hands due to hypocalcemia as pH up
how to counteract hypocanea
breathe in paper bag= expired air, with elevation in CO2
Breathing Cessation. Stop breathing voluntarily - Hold breath!! Greater urge to breathe, lose consciousness Respiratory center resumes Normal automatic control of Pulmonary Ventilation.
apnea
during exercise what happens to ventilation
increases
how much does ventilation increase during vigorous exercise
10-20 fold
increased ventilation to match metabolic needs- not alter oxygen and CO2 levels
hyperpnea
a sudden increase in altitude from sea level to >8000 feet casues PO2 and atm pressure to increases or decrease
decrease
S&S of acute mountain sickness
H/A
SOB
nausea
dizzy
severe AMS
lethal pulmonary and cerebral edema
long term AMS
acclimates via increased ventilation and less oxygen available
what do kidneys produce
erythropoietin
red bone marrow produces
RBCs
how to treat AMS
dexamethasone and acetazolamide
oxygen
lower altitude
