respiratory pathophysiology
Terms
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- dorsal respiratory group
-
dorsal portion of medulla oblongata
mainly inspiration - dorsal resp. group receives info. from?
-
1) chemoreceptors
2) baroreceptors
3) other receptors in the lungs - ventral respiratory group
-
ventrolateral portion of medulla
inspiration or expiration
involved in increased levels of ventilation - pneumotaxic center
-
dorsally located in the pons
rate and pattern of breathing
limits the duration of inspiration
increase the RR - strong signal from pneumotaxic center
- reduces the time of inspiration
- weak signal from pneumotaxic center
- increase the time of inspiration
- which resp. group is most important in controlling resp.
- dorsal resp. group
- ultimate goal of resp.
- to maintain proper [H], [O2], and [CO2] in the tissue
- what stimulate the resp. center directly
- increased [H] and [CO2], not [O2]
- [O2]
-
no direct effect on the resp. center
acts through the peripheral chemoreceptors - where chemoreceptors located?
- carotid and aortic bodies
- net diffusion of a gas in one direction
- is a direct effect of its [ ] gradient
- total pressure of a gas
- is directly proportional to the [ ] of the gas molecules
- partial pressure
- the pressure of a specific gas
- pressure of a gas in solution is determined by?
- [gas] and the solubility coefficient
- Henry's Law
- pressure=[dissolved gas]/solubility coefficient
- the solubility coefficient at body temp.
-
O2=0.024
CO2=0.57 - net diffusion
- is determined by the difference bet. the 2 partial pressure
- PP of a gas in the alveoli (O2) > blood
- go to the blood
- PP of a gas in the blood(CO2) > alveoli
- will escape to the alveoli
- respiratory volumes
-
1) TV
2) IRV
3) ERV
4) RV - TV
-
tidal volume
500 ml
amt. of air inhaled or exhaled with each breath under resting conditions - IRV
-
inspiratory reserve volume
3100 ml
amt. of air that can be forcefully inhaled after a normal TV inhalation - ERV
-
expiratory reserve volume
1200 ml
amt. of air that can be forcefully exhaled after a normal TV exhalation - RV
-
residual volume
1200 ml
amt. of air remaining in the lungs after a forced exhalation - respiratory capacities
-
1) TLC
2) VC
3) IC
4) FRC - TLC
-
total lung capacity
6000 ml
max. amt. of air contained in lungs after a max. inspiratory effort - TLC =
- TV+IRV+ERV+RV
- VC
-
vital capacity
4800 ml
max. amt. of air that can be expired after a max. inspiratory effort - VC =
-
TV + IRV + ERV
should be 80 % TLC - IC
-
inspiratory capacity
3600 ml
max. amt. of air that can be inspired after a normal expiration - IC =
- TV + IRV
- FRC
-
functional residual capacity
2400 ml
volume of air remaining in the lungs after a normal TV expiration - FRC =
- ERV + RV
- PO2
- alveoli > blood > tissue
- PCO2
- tissue > blood > alveoli
- Va/Q = 0
-
Va is 0 and there's still perfusion
no gas exchange
no ventilation -
Va/Q = 0
PCO2 and PO2 ? -
same as venous blood
PCO2 = 45 mm Hg
PO2 = 40 mm Hg - Va/Q = infin.
-
Va is perfect but no perfusion
no gas exchange -
Va/Q = infin.
PCO2 and PO2 ? -
same as inspired air
PCO2 = 0 mm Hg
PO2 = 149 mm Hg - normal Va/Q
-
PO2 = 104 mm Hg
Pco2 = 40 mm Hg - physiological shunt
- the amt. of non-oxigenated blood/min.
- physiologic dead space
-
the sum of 2 types of wasted ventilation
1) if Va/Q = higer than normal
2) vent. of the anatomical dead space areas - O2-Hgb dissociation curve
- show a progressive increase in the % of Hgb bound to O2 as the PO2 increase
- shifts to right
- decreased affinity
- cause for shifts to right
-
acute acidosis (< Ph)
increased PCO2
increased temp.
increased levels of 2,3-DPG
abnormal Hgb
exercise - shifts to left
- increased affinity
- causes for shifts to left
-
acute alkalosis (> Ph)
decreased PCO2
decreased temp.
decreased levels of 2,3-DPG
carboxyhemoglobin
methemoglobin
abnormal Hgb