exam 1 class 8 Flashcards
does gas exchange in the lungs move down or up conc. gradient?
down
what happens when arterial blood reaches the tissue capillaries
gradient is reserved
what is the main factor that affects atmospheric oxygen content
altitude
does partial pressure increase or decrease s you go from sea level to higher altitudes
decreases
low alveolar ventilation
hypoventilation
lower than normal values of fresh air in the alveoli and less blood oxygen level
hypoxia
factors affecting alveolar gas exchange
1. oxygen reaching the lungs ->
composition of inhaled air
factors affecting alveolar gas exchange
2. alveolar ventilation ->
- airway resistance
- ability of lung to stretch
- rate and depth of breathing
CNS depression does what ?
slows ventilation rate and decreases depth of breathing
causes of CNS
depression
alcohol poisoning and
drug overdoses
The transfer of oxygen from alveoli to blood requires diffusion across the barrier created by__________________
type I alveolar cells and the capillary endothelium
factors affecting aveolar gas diffusion
3. gas diffusion between air and blood
- surface area
- diffusion distance
- barrier permeability
- concentration gradient
factors that make alveolar gas exchange much harder?
- decrease in amount of alveolar SA available
- increase in thickness of the alveolar capillary exchange barrier
- increase in diffusion distance between the alveolar air space in the blood
factors affecting alveolar gas exchange
4. Adequate perfusion of
the alveoli
how good
is the blood capillary
network
how much of O2 in blood is transported as bound hemoglobin
98%
how much of O2 is transported as dissolved in blood plasma
2%
one hemoglobin molecule has the potential to bind to
4 oxygen molecules
Hemoglobin bound to oxygen is called
oxyhemoglobin (HbO2)
The absolute
concentration of
dissolved gases also
depends on?
the solubility, ⍺, of oxygen
in water
factors affecting alveolar gas exchange
3. gas diffusion between the blood and air
- surface area
-diffusion distance - barrier permeability
- concentration gradient
what gives red blood cells their color
hemoglobin
3 ways carbon dioxide is transported
- cellular respiration (exhaled)
- to much CO2 can alter pH
- to much CO2 can depress CNS function and lead to death
elevated CO2
hypercapnia
pH disturbance by to much CO2
acidosis
how much CO2 is dissolved in plasma
7%
how much CO2 diffuses into red blood cells
93%
what is it called when CO2 binds to hemoglobin
carbaminohemogolbin
in RBC how much CO2 binds to hemoglobin
23%
in RBC how much CO2 is converted to bicarbonate ions and goes into the plasma
70%
steps of the first mechanism to remove free H+ and CHCO3
- bicarbonate leaves RBC on anitport protein
- chloride shift - HCO3 for Cl-
- ( the anion exchange keeps the cells electrical neutrality)
- transfer into plasma makes buffer available to moderate pH changes
what is the most important extracellular buffer in the body
biocarbonate
steps of the 2nd mechanism to act as intracellular buffer to maintain pH
- removes free from the red blood cell cytoplasm
If blood is elevated much above normal, the hemoglobin buffer cannot soak up all the produced from the reaction of and water. In those cases, excess accumulates in the plasma, causing the condition known as?
respiratory acidosis
