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How do O2 and Co2 cross the membranes of the body?
What is atmospheric pressure?
Force resulting from collision of gas molecules.
What is a gas partial pressure?
Pressure contribution of one gas type
What determines a liquids capacity/concentration of a gas?
- Partial pressure
- Solubility of a gas
During diffusion each gas has its own ___________ independent of the other gases.
What is Henry's Law?
- Net diffusion of molecules will continue until gas partial pressure is equal on both sides of a membrane
- Does not mean there is equal concentrations on both sides.
What five things are included in the Diffusion barrier for O2 and CO2 entering and exiting the capillaries in the lungs?
- RBC membrane
- Capillary membrane
- Interstitial Fluid
Is there an internal pacing system in the lungs?
Without central innervation to ventilation muscles what happens to ventilation?
What CNS centers coordinate ventilation?
- dorsal & ventral respiratory group
- apneustic center
- pneumotaxic center
What are humoral agents?
- Agents carried by the blood that alter ventilation by acting on chemoreceptors
What produces 70% of the breathing drive?
Where are ventilation CNS chemoreceptors located?
4th ventricle floor
What stimulates ventilation CNS chemoreceptors?
Describe the CO2 bicarbonate system:
CO2 + H2O Û H2CO3 Û HCO3- & H+
Breifly describe how CNS ventilation chemoreceptors work:
- CO2 enters the CSF
- Undergoes the Bicarbonate reaction with H20
- Released H+ stimulates the receptors
- H+ FROM THE BLOOD DOES NOT STIMULATE THE RECEPTORS
What are peripheral chemoreceptors stimulated by?
- CO2, H+ and O2
- O2 is the least important
Where are peripheral chemoreceptors for ventilation located?
Carotid and Aortic bodies
What sensory adaptors are found in the lung?
- Slowly adapting pulmonary stretch receptors
- Rapidly adapting pulmonary stretch receptors
- C-fiber endings
Pulmonary Slowly adapting pulmonary stretch receptors control what?
Pulmonary Rapidly adapting pulmonary stretch receptors control what?
What is the purpose of C-fiber endings in the lungs?
What activates C-fiber endings in the lungs?
Respiratory pattern generator is located where?
Control of ventilation involves receptors located where?
central & peripheral
What molecule normally determines ventilation?
What types are Sensory receptors in the lungs?
mechano- & chemoreceptors
What is the concentration of Hb in the blood?
15 grams Hb / 100 mls blood.
How much O2 Can the Hb carry?
1 gram Hb can carry 1.34 mls O2.
How much 02 can the blood carry?
100 mls blood can carry 20 mls O2.
How much 02 can be dissolved in the blood?
What is the Bohr effect?
- reduction hemoglobin affinity for oxygen
- Due to:
- carbon dioxide increase and decrease in pH in the blood
What is the Partial pressure of O2 in the arterial capillaries?
What is the Partial pressure of O2 in the Interstitial fluids?
What is the Partial pressure of O2 in the Cells?
What percent of C)2 dissolves in the plasma?
9% or 29mL/L
What is Carbamino compound?
CO2 and Hb
How much C02 is carried as a Carbamino compound?
Can C02 be displaced by )2 when attached to Hb?
How is C02 primarily transported?
As a bicarbonate ion (64%)
Is the Co2 bicarbonate reaction fast or slow?
What speed up the Co2 bicarbonate reaction?
Carbonic anhydrase of RBCs
What is the Chloride shift?
The movement of Cl- into the cell to balance H+ produced by CO2
O2 depends primarily on what for transportation?
Hb for its transportation
Hb saturation depends upon what?
the surrounding PO2
Why is O2 released at the tissue capillaries?
Because of low cellular PO2
CO2 is carried to the blood 3 ways, all driven by what?
All driven by PCO2.
What is the most prevalent form of CO2 transfer?
HCO3- is most prevalent.
What does Carbonic anhydrase do?
converts CO2 to HCO3- & back again.