Glossary of Respiratory Tract

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Inhalation Uses
External Intercostals (Pull Up)
Collapsed Lung
Look normal, lungs still go up and down with chest rising. No air going in.
Exhalation (Expiration) Uses
-At rest, relaxation of inspiratory muscles
-Contraction of abdominal muscles to force diaphragm back up.
-Contraction of internal intercostals (depress ribs)
Air Flow
-Governed By
Resistance of flow within bronchioles
(muscular, can change diameter)
Bronchiole Smooth Muscle (Sympathetics)
Sympathetics-->NorE-->B-receptors-->Dilation-->Air Flow (UP)
Bronchiole Smooth Muscle (Parasympathetics)
Parasympathetics-->ACh--> Muscarinic-->Constriction
Bronchiole Smooth Muscle (Histamine)
Histamine-->Constriction (Acts like parasympathetics)
Bronchiole Smooth Muscle (CO2 & Carbonic Acid)
CO2 & (Carbonic Acid)-->Dilation (acts like sympathetics)
Tidal Volume
Amount of air inhaled and exhaled at rest
Inspiratory Reserve
Men > Females
Depends on persons size
Expiratory Reserve
Additional Expiration
Lungs at rest, closer to collapse, normally
Vital Capacity
Total amount you can bring in and out (Breath all the way)
Forced Vital Capacity
Same volume as vital capacity
Inhale all the way and blow out as quick as possible
Amount of air out in 1 second
Residual Volume
Dead air space
Air still in tubes when all is exhaled
Respiratory Rate
At rest, rate is at tidal volume.
12 breaths/minute
inhale:exhale, 2:3
Normal basal rate
Control of Ventilation
Controlled by respiratory centers located above spinal cord in the medulla oblongata
Inspiratory Center
Dorsal Respiratory Group
Basal Respiratory Center
Expiratory Center
Ventral Respiratory Group
Forced Expiration
Inspiratory Center Physiology
No stimulation needed
No resting membrane potential, but heads towards one (-70mV)
Inspiratory Center Channels
Leak (Na, K)
Ligand Regulated (Na, K)
Volt Regulate (Na activation, Na inactivation, K)
Inspiratory Center: Ligand Regulated Channels
(Don't need ligand regulating channels but they can influence conduction)
Inspiratory Center: Leak Channels
Na, K
No resting potential at -70mV.
Due to leak channels it gains an action potential @ -70mV
Inspiratory Center: Volt Regulated Channels
Na Activation Gate:
-Open @ -70mV
-Close@ -90mV
Na Inactivation Gate:
-Open @ -90mV
-Close @ +30mV
K Channel
-Open @ +30mV
-Close @ -90mV
Inspiratory Center
Factors Influencing Autodepolarizing Neurons
pH of CSF
Carbon Dioxide in Plasma
Cerebral Control
pH of Cerebrospinal Fluid
Essentially, Filtered Plasma
Chemoreceptors in brainstem for [H+]-->(synapse)Autodepolarizing cells
[H+] concentration UP
[H+]UP-->Chemoreceptors--> ACh-->Inspiratory Neurons' Na+ channels-->Ventilation Rate (UP)
[H+] concentration DOWN
[H+]DOWN (pH UP)--> Chemoreceptors (different than before) --> Glutamic Acid-->Inspiratory Neurons' K+ Channels--> Ventilation Rate (DOWN)
Ascidic pH is due to?
Carbon Dioxide, Carbonic Acid, High H+
What happens when breath is held?
Carbon Dioxide (UP)
pH (UP)
(Ventilation Up when resumed)
After Hyperventilation?
Breathing becomes slow due to higher pH since CO2 is gone
With Helium?
CO2 remains same, respiratory rate same since CO2 same, but not breathing Oxygen. Oxygen isn't monitored
Carbon Dioxide in plasma
Carbon Dioxide chemoreceptors in aorta and interior carotids
Levels of Carbon Dioxide?
Carbon Dioxide (UP)-->ACh--> Na+-->Ventilation (UP)
Carbon Dioxide (Down)--> Glutamic Acid --> K+ --> Ventilation (DOWN)
Cerebral Control of respiration
Motor Central-ACh--> Inspiratory Centers
Expiratory Center Contains?
Inspiratory Neurons!
Not Autodepolarizing (regular neurons)
Expiratory Center: Inspiratory Neurons synapse on to?
More muscles of inspiration
Some synapse onto inspiratory muscles, others synapse onto abdominal muscles.
Expiratory Center:
Inspiratory Neurons are synapsed onto by?
Cerebral Neurons
Gas Exchange
Atmosphere<-->Lungs(alveoli)<-->Blood<-->Tissue Cells
Atmospheric Gases and Percentage
(Inert Gases)-.97%
Atmospheric Air Pressure (Sea Level)
Partial Pressure formula?
P(gas)=760mmHg x (% of gas of total)/100
160mmHg of O2
0.25mmHg of CO2
What else is always present and contributes to air pressure
Vapor Pressure
Vapor Pressure Depends on?
Amount of water present
Real equation for partial pressure in atmosphere?
760mmHg-P(H20)=Total pressure of N2+O2+CO2+(I)
Air inhaled is saturated with water since water lines nose and mouth
H2O saturation at body temperature (37C)?
P(water) @ saturation=47mmHg
P(O2) In upper respiratory tract?
(760mmHg - 47mmHg)x 0.21= 150mmHg
P(CO2) In upper respiratory tract?
(760mmHg - 47mmHg) x .00033 = .24mmHg
Residual Volume Composition
Increased CO2, Decreased O2 since air stays in lungs
-Air inhaled enters alveoli and mixes with air already in alveoli (residual volume)
Alveolar Air
Air inhaled is not same composition as air in alveoli
Henry's Law
Amount of gas in liquid depends on:
1) solubility of gas
2) Partial pressure of gas outside of liquid
Gas Pressure in Alveoli
Gas Pressure in Plasma Returning to Alveoli (Veinous Blood)
Gas Pressure in Tissues
Gas Pressure in Plasma Leaving Alveoli
Oxygen in body
Very low solubility, especially at body temperature
Increases amount of Oxygen by 67x's
Oxygen Within Lungs
Air O2-->Plasma O2-->O2+Hb--> HbO2 (Oxygen Loading)
Hb removes oxygen from plasma
Pressure not as important
Oxygen Within Tissues
HbO2 --> Hb+O2 --> Plasma O2 --> Tissue Oxygen (Oxygen Unloading)
Tissues remove Oxygen from plasma
Hb loading and unloading
Unloading varies depending on:
1) Intracellular P(O2) of 'working' tissue.
2) Temperature
3) pH
4) Diphosphoglycerine (DPG)
Intracellular P(O2) of 'Working' Tissue
'Oxygen Dissociation Curve'
Resting cells at normal metabolism-75%
Lungs w/Oxygen is 95% saturated
Right Shift-Oxygen more likely to dissociate
Left Shift-Oxygen less likely to dissociate from Hb
High temperature-Right shift
More CO2, more Carbonic Acid, Using more Oxygen--> Ascidic

More H+, Less oxygen binding to Hb
Diphosphoglycerine (DPG)
More DPG, Less Oxygen bindability

DPG attaches to Hb, change binding site for Oxygen so less binds
Epinephrine Up--> DPG Synthesis Up
Less Oxygen available, so more available to body
Carbon Dioxide
24x's more soluble in water than oxygen
CO2+H2O<-->H2CO3<-->H+ +HCO3-

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