Respiratory #3 Flashcards
What determines the total oxygen content of the blood?
the PO2 and the hemoglobin concentration of RBCs
What are hemoglobin molecules composed of
4 polypeptide globins and 4 iron containing disc shaped pigment molecules (hemes)
Normal heme bonded with oxygen
oxyhemoglobin
When oxyhemoglobin releases o2 to tissues
deoxyhemoglobin or reduced hemoglobin
hemoglobin that cannot participate in oxygen transport
methemoglobin
reduced heme combined with CO
carboxyhemoglobin
measured to ssess how well lungs oxygenate the blood
percent oxyhemoglobin saturation
______ has a cranberry juice color and _____ has a tomato juice red color
carboxyhemoglobin, oxyhemoglobin
hemoglobin concentration below normal
anemia
hemoglobin concentration above normal
polycythemia
Production of hemoglobin and RBC controlled by _____ produced by _____ in response to ______
erythropoietin, kidneys, hypoxia
Why is hemoglobin concentration higher in men?
RBC producion promoted by androgens
Loading reaction
deoxyhemoglobin combine to form oxyhemoglobin
unloading reaction occurs where and produces what?
tissue capillaries, free oxygen and deoxyhemoglobin
High PO2 favors what reaction?
loading reaction
Percent oxyhemoglobin saturation in veins when person is at rest
75%
Graphic illustration of the percent oxyhemoglobin saturation at different values of PO2
oxyhemoglobin dissociation curve
Shape of oxyhemoglobin dissociation curve
S shaped, sigmoidal
The difference between theveins at rest and the arteries
amount of O2 unloaded to tissues at rest
What affects loading and unloading reactions
affinity (bond strength) and PO2 of the environment
What is the Bohr effect?
Affinity of hemoglobin and oxygen is decreased when pH is lowered and increased when pH is raised
Increased temperature (such as in skeletal muscles) affects affinity how?
Lowers affinity
How is the dissociation curve changed by lwoering of H
shifted to the right (more o2 unloaded)
Hyperventilation would affect the dissociation curve how?
shift to the left
Example of hemoglobinopathy?
sickle cell disease
In sickle cell disease a person produces _____ instead of ______
hemoglobin S, hemoglobin a
What occurs as a result of the sickle shaped RBCs
reduced flexibility (causes infarcts) and hemolysis
What drug treats sickle cell anemia?
hydroxyurea
Family of hemoglobin diseases found among Mediterranean people
thalassemia
Myoglobins dissociation curve is ____ of that of hemoglobin
left (higher affinity for O2)
T/F the affinity of carbon monoxide is greater for myoglobin that hemoglobin
true
What is the most common way CO2 is carried in the blood
bicarbonate ion
What helps catalyze carbonic acid
carbonic anhydrase
What does the Bohr effect encourage
increased conversion of oxyhemoglobin to deoxyhemoglobin
What is the purpose of the chloride shift?
carbon dioxide transport enhances o2 unloading and o2 unloading improves co2 transport
Average blood pH
7.4
What acids in the blood are volatile?
CO2
Why are lactic acid, fatty acids, and ketone bodies considered non volatile
because they can not be eliminated through ventilation
What is the major buffer in the plasma and what does it buffer?
bicarbonate, H+
Respiratory acidois is caused by
hypoventilation
the excessive production of nonvolatile acids
metabolic acidosis
diabetes mellits causes excessive production of what nonvolatile acid
ketone bodies
Besides excessive nonvolatile acids what else causes metabolic acidosis?
loss of bicarbonate to buffer non volatile acids
Excessive vomiting could lead to
metabolic alkalosis (inadequate non volatile acids)
What represents the repspiratory component of acid base balance?
plasma co2 concentration
what represents the metabolic component?
free bicarbonate concentration
A normal arterial blood PH is obtained when
there is a proper ratio of bicarbonate to co2
A primary disturbance in metabolic component leads to
a secondary change in respiratory component
How does hyperventilation lead to tetany?
elevates blood pH and causes increased amount of free ca2+ to bind to plasma albumin—> reduces free calcium and so nerve cells become more excitable—> hypocalcemic tetany
Metabolic acidosis would cause a person to ______ which would lead to _____ to compensate
hyperventilate, secondary respiratory alkalosis
T/F blood PCO2 is significantly increased during exercise
False- Po2, PCO2 and pH stay constant
Oxyhemoglobin saturation above 7500 feet
92-93 percent
At 5000 feet and above, decreased arterial pO2 stimulates ____ to produce increase in ______
carotid bodies, ventilation
Increased breathing at high altitudes is called
hypoxic ventilatory response
T/F PO2 of arterial bood decreases with increased altiitude regardless of ventilation
true
What provides partial compensation for chronic hypoxia at high altitudes?
Nitric oxide transferred to rhythmicity center of medulla, affinity of hemoglobin for o2 is reduced (higher proportion of O2 unloaded)
used to treat symptoms of altitude sickness and its mechanism
diamox (acetazolamide) carbonic anhydrase inhibitor
Why does carbonic anhydrase inhibitor reduces symptoms of altitude sickness
increases bicarbonate excreted in urine by kidneys, blood becomes more acidic which makes body thick it has excess CO2 and eliminates excess CO2 w/deeper faster breathing, increases O2 in blood
Acute mountain sickness can lead to what problems?
high altitude pulmonary/cerebral edema
How do the kidneys react to decreased tissue oxygen
secrete erythropoietin to make more hemoglobin
Ways people living at higher altitudes compensate for hypoxia?
increased hemoglobin and RBC production (polycythemia), increased chest dimensions, increased capillaries
