Groups of neurons in the brainstem which control breathing, functions to cause inhalation and expiration and adjust rate and depth of breathing.
What part of the brain stem controls breathing?
List the 4 respiratory groups.
1) Pontine 2) Medullary 3) Ventral 4) Dorsal
These stimulate the diaphragm to contract, beginning inspiration.
What condition stimulates the central chemoreceptors to cause a person to breathe?
High P of CO2 and pH
What condition stimulates the peripheral chemoreceptors to cause a person to breathe?
Low P of O2
How does the rate of a person's breathing affect the level of CO2 in their blood?
Since CO2 is a metabolic waste of respiration, increased breathing would lead to a decrease in CO2 in blood, and vice versa
If the blood level of CO2 increases, what does the pH do?
How would blood pH affect breathing rate?
Cellular respiration and control of blood pH explain why we must obtain O2 and get rid of CO2 If pH is too high, CO2 levels would be too low and breathing rate would decrease, and vice versa
What is the correlation between ventilation rate and CO2 levels?
If CO2 levels are too high, ventilation rate will increase in order to get rid of CO2, and vice versa
For a healthy individual, what is the primary factor stimulating increased breathing?
Increased blood P of CO2 (for COPD, its less than 50% of normal P of CO2)
How is the control of breathing for someone with COPD different than a healthy person?
Since a person with COPD has a difficult time getting rid of CO2, (in a state of constant acidosis) they gradually adapt to high levels of CO2 so it takes unusually low P of O2 to stimulate breathing
Amount of pressure exerted by a single gas in a mixture of gases.
These sense changes in partial pressure of CO2 and blood pH
Theses sense changes in partial pressure of oxygen in blood.
This helps regulate the depth of breathing when the stretch receptors are stimulated to prevent over-inflation of lungs.
Hering Baur Reflex (Inflation Reflex)
Slow breathing, that raises the blood concentration of CO2.
Rapid and deep breathing, that lowers the blood concentration of CO2.
What is Dalton's Law?
All the partial pressures added together equal the total pressure exerted by the gas mixture.
What is the Carbonic Acid Dissociation Formula?
H2O + CO2 = H2CO3 = H+ + HCO3-
What is Fick's Law?
Rate of Diffusion: (Dk x CG x SA x T)/(MW x MT)
How do we measure the concentration of gases to determine direction of diffusion?
CO2 diffuses from blood to alveolar air because the P of CO2 is higher in blood; O2 diffuses from alveolar air to blood because the P of O2 is higher in alveolar air
Tiny openings in the walls of some alveoli.
Phagocytic cells that function to destroy airborne agents that reach the alveoli.
The site of gas exchange between alveolar air and the blood.
List the 3 methods by which CO2 is transported to the lungs.
1) Dissolved in Plasma 2) Bound to hemoglobin 3) As bicarbonate ions (most important method)
A structure that functions to carry oxygen to tissues.
The percentage of heme groups containing bound oxygen at any given moment.
This shows the saturation of hemoglobin at different partial pressures of oxygen.
Oxygen Hemoglobin Saturation Curve
What is the Bohr Effect?
When hemoglobin will release more O2 when the conditions have lower P of O2, lower pH, or higher P of CO2; causes a "right shift"
This is formed when CO2 molecules bind to the amino group on the hemoglobin molecule.
The enzyme located in red blood cells which speeds up the carbonic acid dissociation.
Where does the conversion of CO2 to bicarbonate ions occur?
Red Blood Cells
What causes the Chloride Shift?
It occurs as HCO3- leaves the red blood cell and enters the blood plasma, this causes the blood plasma to become more negative, to correct this, chloride is removed from blood plasma and enters the red blood cell
Increased arterial P of CO2
Decreased arterial P of CO2
When arterial blood pressure decreases below its normal range, the respiratory minute volume increases to ensure adequate O2 delivery.
What is the Law of LaPlace?
The pressure created within the alveoli is directly proportional to the surface tension and inversely proportional to the radius of the alveoli. P=2T/r
According to law of LaPlace, if the alveoli get smaller, the pressure to collapse _____, and if the alveoli get larger the pressure to collapse _____.