Pink sheets from last year Flashcards
The Hering-Bruer reflex responds
to excessive stressing of the lung
J receptors (C fibers) are sensitive to
pulmonary edema such as occurs in congestive heart failure.
A repeated breathing cycle consisting o f a period of apnea replaced by a period of increasing rapid and deep breathing is referred to as:
Cheyne-Stokes breathing, associated with cardiac arrest.
The Ventral respiratory group is responsible for
forced expiration
The dorsal respiratory group is responsible for
establishing a ramp signal during normal breathing.
The pneumotaxic center controls
the switch off point of the inspiratory ramp signal
What monitors carbon dioxide levels via pH? and therefore controls the rate of respiration?
Central chemosensitive receptors located in the brain stem
The peripheral chemosensitive receptors
are involved in controlling the rate of respiration mostly monitor oxygen partial pressure in arterial blood.
what do you call the peripheral chemosensitive receptors?
carotid and aromatic receptors
The pneumotaxic center is the primary controller of the
rate and depth of breathing.
One gram of hemoglobin can transport
1.34 ml of oxygen
At rest, arterial blood carries _____ml oxygen per deciliter, and returning venous blood carries about _______ ml of oxygen per deciliter.
19.4, and 14.4
At rest, the oxygen utilization coefficient is
about 25%
Factors that shift the oxygen-hemoglobin curve to the right and downward, causing more oxygen to be released from the hemoglobin include:
a decrease in pH and an increase in carbon dioxide, and increase in BPG and and increase in temperature.
Bohr effect occurs when there is an increase in blood carbon dioxide causing oxygen to be displaced from hemoglobin. What happens to the curve?
Shifts oxygen-hemoglobin dissociation curve to the right
The displacement of carbon dioxide that occurs when hemoglobin binds with oxygen in the lungs is called
haldane effect
In carbon monoxide poising the p02 of the blood may be normal and the blood may be
BRIGHT RED
When intracellular pO2 is above 1mmHg the limiting factor for cellular chemical reactions is
ADP
In order to maintain electrical neutrality, red blood cells utilize what?
bicarbonate/ chloride ion co-transporter in opposite directions
Pulmonary edema occurs when
pulmonary capillary pressure exceeds 25 mmHg
The most common causes of pulmonary edema are:
left heart failure, mitral valve diseases, breathing noxious substances.
At sea level, the partial pressure of a specific gas in air can be determined by multiplying the percent of gas in the air mixture by
760 mmHg.
Henry’s law states that the amount of a given gas that dissolves in a given type and
volume of liquid is directly proportional to the partial pressure of that gas at equilibrium
Daltons law states that
the total pressure exerted by the mixture of a non-reactive gasses is equal to the sum of the partial pressure of the individual gasses.
Boyle’s law
states that for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional
The addition of water vapor to the mixture of air in the alveoli decreases the partial pressures of all the other
gasses in the mixture.
alveolar pressure at the end f a normal quiet inspiration cycle is
0 mmHg
Normally, Va/Q= 0.8
pulmonary= 5L/min; Ventilation is approx 4 L/min
Va/Q=0 when
Va=0 but there is still perfusion; this is due to airway obstruction (mucous plug). the blood gas composition remains unchanged.
Va/Q= infinity when Q=0, but there is
still ventilation (no gas exchange) this is due to vascular obstruction (pulmonary embolism) alveolar gas composition remains unchanged because there is no blood contact. This creates a physiologic shunt.
How much blood volume is found in the lungs?
9% or 450 ml
The pulmonary artery and its branches can be described as
low pressure/ high flow system while the bronchial arteries (supplying the lung tissue itself) can be described as high pressure / low flow system.
The difference between the mean pulmonary arterial pressure and the diastolic pressure in the left atrium is
the pressure gradient in the pulmonary system. This gradient is approximately 7 mmHg
The mean normal pressure in the left atrium is
2mmHg
In order to increase blood flow to the lungs during exercise, the
number of open capillaries increases as much as 3 x normal, the capillaries become more descended and there is an increase in pulmonary arterial pressure.
Normally at rest, the apices of the lungs show a zone 2 pattern of blood flow while the remainder for the lungs shows what?
zone 3 pattern
Because of a physiologic shunt,
blood in the systemic arteries contains less oxygen per deciliter than blood that has equilibrated with the alveolar air.
Reduction f blood flow to a portion o the lung
lowers the alveolar pCO2 and results in a constriction of the bronchi supplying that portion of the lung.
What is compliance
the volume by which the lungs and thorax increase for each unit pressure change in the transplumonary pressure
What is the carina?
located at the bifurcation of the trachea into the 2 primary bronchi, produces a strong cough reflex.
What is the difference between the bronchi and bronchioles?
bronchioles lack cartilaginous plates
What is the vital lung capacity?
the sum of the inspiratory reserve volume, tidal volume and expiratory reserve volume.
What is tidal volume?
500 ml, the volume of air that is inspired or expired with each breath at rest.
Inspiratory reserve volume
3000 ml is the volume of air that can be inspired in addition tot eh tidal volume with forceful inspiration
expiratory reserve volume
1100 ml is the additional volume of air that can e expired at the end of tidal volume by forceful expiration.
Residual volume
1200 ml is the volume of air remaining in lungs after forceful expiration.
Vital capacity
4600 is the sum of all the volumes that can be inspired or exhaled.
total lung capacity
5800 is the sum of all the volumes= vital capacity plus residual volume
Total volume of gases that enter the spaces participating in gas exchange per minute =
alveolar ventilation
What is anatomic dead space?
Space in the trachea, bronchi, and bronchioles
What is physiological dead space?
includes the anatomic dead space + ventilated alveoli with poor or absent perfusion
Alveolar ventilation:
(tidal volume - dead space) x breathing rate= .35 x breathing rate
Total dead space in normal individual?
.15 Liters
What is alveolar pressure?
pressure of the air inside the alveoli
What is transpulmonary pressure?
difference between the alveolar pressure and the pleural pressure.
During inspiration, pleural pressure
-5 to -7.5 cm H2O
During expiration pleural pressure
-7.5 to -5 cm H2O
During inspiration alveolar pressure:
0 to -1 cm H2O
During expiration alveolar pressure:
0 to 1 cm H2O
Minute ventilation
is equal to tidal volume x respiration rate.
For the average size alveolus, what is the tension pressure
4 cm H20 pressure with surfactant and 18 cm H2O without surfactant.
Compliance is directly proportional to
distensibility and volume and indirectly proportional to pressure.
What is the most important extracellular buffer?
bicarbonate buffer
Carbonic anhydrase is important for…
forming carbonic acid from carbon dioxide and water
In a rubber system, what happens if you add a strong acid?
it forms a weak acid and addition of a strong base leads to the formation of a weak base
How does bicarb excreted by the kidney help?
decreases blood carbon dioxide levels resulting in decrease in respiration rate.
What is the most important buffer system for the renal tubular fluid and intracellular fluids?
the phosphate buffer system
How do we remove nonvolatile acids
renal excretion
How does hydrogen ion secretion happen?
via secondary active transport (sodium) occurs in all the parts except the descending and ascending thin limbs of the loop of henle
where is primary active hydrogen secretion done?
late distal tubules in intercalated cells. Involves Hydrogen transporting ATPase
How much bicarb is reabsorbed in the proximal tubule?
80-90%
what is metabolic acidosis/alkalosis
change in pH due to an increase or decrease of bicarb ion
what happened in metabolic acidosis:
new bicarb ion is added to the ex fluid
what happens in metabolic alkalosis:
bicarb ions are removed from EC fluid by renal excretion
what is the lower ph limit of the kidney?
4.5
What is respiratory alkalosis/acidosis?
change in plasma pH due to an increase or decrease in carbon dioxide
Kidneys respond to respiratory acidosis by
adding new bicarb ion to the ecf
Decreased ventilation is compensation for what?
metabolic alkalosis.
what is the normal intracellular concentration of potassium ion?
140 mEQ/l
What does aldosterone react to?
increase in extracellular potassium
Reabsorption of potassium ion occurs where?
proximal tubule and the ascending limb of henle
secretion of potassium occurs where?
late tubule and collecting duct
Small changes in potassium concentration cause
large changes in aldosterone secretion by adrenals
increased sodium intake decreases aldosterone secretion and therefore
potassium excretion however, increased sodium intake also increases GFR and decreases proximal tubular reabsorption of sodium
Increased levels of PTH, plasma concentration of phosphate and metabolic acidosis decrease what?
calcium excretion
Insulin and aldosterone both work to
increase uptake of potassium by cells
hypokalemia results from excess secretion of Aldosterone
Conn’s syndrome
hyperkalemia results from efficiency in aldosterone secretion
addison disease
almost all the filtered calcium is reabsorbed by what?
the kidney.
