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33 Cards in this Set

  • Front
  • Back
Respiratory Tree
Vocal Cords
Type II cells
produce surfactant- keep lung surface from collapsing
Ciliated epithelium and mucus
-Terminal Bronchioles
Smooth muscle
-Sympathetic causes dilation of smooth muscle
-Parasympathetic causes constriction of smooth muscle
-Asthma and treatment with epinephrine
Alveolar Sacs
-Total area in average person is 50-90 square meters 30-50 times external body surface
-Production of surfactant to reduce surface tension inside of alveolar sacs. Lack of this will cause collapse of alveolar sacs.
-Very delicate. Smoking can cause emphysema
Penetration of the pleural membrane
Results in collapse of the lung
Breathing and its control
Control by phrenic nerve
-Intercostal muscles (muscles between ribs)
-Respiratory Center in the medulla oblongata
Inspiratory center
Expiratory center
-Contribution of the pons
-Sleep apnea
Peripheral Chemoreceptors
-Carotid body
-Aortic body
-Response to low oxygen
-Response to increased hydrogen ion concentration (acidity)
-Response to increased carbon dioxide
Central Chemoreceptors
-In medulla oblongata
-Changes in cerebrospinal fluid pH due to increased carbon dioxide stimulates the central chemoreceptors
Transport of oxygen in the blood:
Use of hemoglobin
-Globin, a protein made up of four highly folded polypeptide chains
-Four iron-containing heme groups
-Each of the four iron atoms can combine reversibly with one molecule of oxygen
-Because oxygen is poorly soluble in the plasma, 98.5% of the oxygen carried in the blood is bound to hemoglobin.
-Binding of oxygen to iron atoms in hemoglobin are not independent of each other.
-The binding of oxygen in hemoglobin is cooperative
-This phenomenon produces a sigmoid curve when percent saturation is plotted against partial pressure of oxygen.
Partial pressure =
= to the percent a gas contributes to the pressure.
Given one atmosphere of pressure = 760 mm Hg
Oxygen occupies 20% of the gas in the atmosphere
Therefore the partial pressure of oxygen is 152 mm Hg.
Respiratory System (Bohr effect)
-The environment surrounding the hemoglobin determines how well it binds oxygen.
-Low pH (high acidity) will cause release of oxygen from hemoglobin (unloading)
-High CO2 presence will cause unloading because it causes lowering of pH.
-High lactic acid also causes unloading
Carbon dioxide is carried in the blood three ways:
Carbaminohemoglobin 20%
Dissolved CO2 --about 7-10%
As bicarbonate -- about 70%
Dalton’s Law of Partial Pressures
-The pressure of each individual gas in a mixture depends solely on the concentration of that gas and is independent of the concentrations of other gases in the mixture.
-In other words, the pressure exerted by a gas depends on its percentage in the mixture.
If 80% of a gas mixture is N2 and 20% is O2, then the PO2 is
PO2 = (20/100)(760mm) = 152 mm Hg
Effect of Water Vapor
Actual Pressure = P - vp
P = the total pressure
Vp = vapor pressure
Example Taking into Account Vapor Pressure
If temperature is 37 ºC, the actual partial pressure of oxygen would be:

PO2 = (20/100)(760-47) = 142.6 mm Hg

Remember, if vp not accounted for, the partial pressure of oxygen would be 152 mm Hg.
Henry’s Law
-When any liquid is in equilibrium with any gas, the partial pressure is proportional to the total ambient pressure and the fractional concentration.
-In other words, the amount of gas dissolved is proportional to the partial pressure.
Oxygen Transported by Plasma
ml O2/ml plasma = a(PO2/PT)
Where a = absorption coefficient of oxygen at 40 ºC.
This is 0.023 ml dissolved gas/ml fluid at 1 atmosphere.
The arterial PO2 is 100 mm Hg
ml O2 in 1 ml plasma = 0.023(100/760)
= 0.003 ml
Or 0.3 ml/100 ml [volume percent]
Oxygen Carried by Red Blood Cells
Hemoglobin a 100 ml of blood is 15 g.
Amount of oxygen that will combine with a gram of hemoglobin is 1.34 ml.
Amount of oxygen per 100 ml of blood is:
1.34ml/g x 15g or 20.1 ml
Compare this 20.1 ml with 0.3 ml in plasma
Ventilation -The exchange of air between the atmosphere and alveoli
F = DP/R
Where F is flow
DP is difference in pressure between two points.
R is resistance
Patm is atmospheric pressure
Palv is alveolar pressure
Intrapleural fluid and transpulmonary pressure
Transpulmonary pressure = Palv - Pip

Where Pip is the pressure in the intrapleural fluid surrounding the lungs.
R is the airway resistance
Events during inspiration
diaphragm and inspiratory intercostals contract -->
thorax expands-->
Pip becomes more atmospheric-->
increase in transpulmonary pressure-->
lungs expand-->
Palv becomes subatmospheric-->
air flows into alveoli
Events during expiration
diaphragm and inspiratory intercostals stop contracting-->
chest wall recoils inward-->
Pip back toward preinspiration value-->
Transpulmonary pressure back toward preinspiration value-->
Lungs recoil toward preinspiration size-->
air in alveoli becomes compressed-->
Palv becomes greater than Patm-->
air flows out of lungs
Lung Compliance- Legend to Fig. 13-14
-A graphical representation of lung compliance. Changes in lung volume and transpulmonary pressure are measured a a subject takes progressively larger breaths.
-When compliance is lower than normal (lung is stiffer), there is a lesser increase in lung volume for any given increase in transpulmonary pressure. When compliance is increased (as in emphysema), small decreases in Ptp allow the lung to collapse.
Hyperventilation- sequence of events by which a low arterial Po2 causes hyperventilation, which maintains alveolar (and hence, arterial) Po2 at a value higher than would exist if ventilation had remained unchanged.
dec. inspired Po2-->
dec. alveolar Po2-->
dec. arterial Po2-->
peripheral chemoreceptors: increase firing--> (reflex via medullary respiratory neurons)
respiratory muscles increase contractions-->
increase in ventilation-->
return of alveolar and arterial Po2 toward normal
Minute Ventilation
Minute ventilation = Tidal volume X Respiratiory rate

Tidal volume is the volume of air entering the lungs during a single inspiration. It is usually about 500 ml.
Stimulating Ventilation
Pathways by which increased arterial PCO2 stimulates ventilation. Note that the peripheral chemoreceptors are stimulated by an increase in H+, whereas they are also stimulated by a decrease in PO2
Induced hyperventilation
Reflexly induced hyperventilation minimizes the change in arterial H+ concentration when acids are produced in excess in the body. Note that under such conditions, arterial PCO2 is reflexly reduced below its normal value.
Inputs stimulating ventilation
Major chemical inputs that stimulate ventilation. This is a combination of Figs. 15-31, 15-33, and 15-35. When arterial PO2 increases or when PCO2 or H+ concentration decreases, ventilation is reflexly decreased
Effect of Exercise
Effect of exercise on ventilation, arterial gas pressures, and H+ concentration. All these variables remain constant during moderate exercise; any change occurs only during strenuous exercise when the person is actually hyperventilating.
Hering-Breuer reflex and the vagus
keeps the body from overfilling with air
juxtamedullary nephron
the renal corpuscle lies in the part of the cortex closest to the cortical-medullary junction. The Henle's loops of these nephrons plunging deep into the medulla and are responsible for generating an osmotic gradient in the medulla responsible for the reabsorption of water.
-vasa recta are in close proximity
cortical nephron
the renal corpuscle is located in te outer cortex and the Henle loops to not penetrate deep into the medulla.