Physiology, Oxygen Transport Flashcards
____ is essential for ATP generation through oxidative phosphorylation, and therefore must be reliably delivered to all metabolically active cells in the body
Oxygen
In the setting of hypoxia or low blood oxygen levels, ____ can rapidly occur
irreversible tissue damage
Hypoxia can result from (3)
- impaired oxygen-carrying capacity of the blood
- impaired unloading of oxygen from hemoglobin in target tissues
- restriction of blood supply
Blood becomes typically saturated with ___ after passing through the lungs
oxygen
____ returns to the heart and is distributed throughout the body by way of the systemic vasculature
Oxygenated blood
____ returns to the heart and is distributed throughout the body by way of the systemic vasculature
Oxygenated blood
Oxygen is carried in the blood in two forms
bound to hemoglobin within red blood cells
dissolved in the plasma
The most critical measures of adequate oxygen transportation are ___ & ___
hemoglobin concentration and oxygen saturation
play essential roles in oxygen transport
lungs
heart
vasculature
red blood cells
are the respiratory organs responsible for the exchange of gasses between the bloodstream and the atmosphere
lungs
Venous blood entering the lungs typically has a partial pressure (PO) of ___
40 mm Hg
Upon passing through the alveolar and pulmonary capillaries, ___ and ___ are allowed to equilibrate across the blood-air barrier, resulting in carbon dioxide removal from the blood and oxygen absorption
oxygen
carbon dioxide
arterial blood leaving the lungs has a PO of approximately ___
100 mg Hg
Oxygenated blood is carried through the cardiovascular system to ___
peripheral tissue
The compensatory mechanism most relevant to the discussion of oxygen transport is the production of the hormone ____
erythropoietin (EPO)
where erythropoietin is produced
peritubular fibroblasts in the renal cortex
stimulates the proliferation and differentiation of red blood cells (erythrocytes) in the red bone marrow
Erythropoietin
The process of ____ will increase the number of
erythrocytes and subsequent increase in total hemoglobin
erythropoiesis
the primary carrier of oxygen in humans
Hemoglobin
Approximately ___% of total oxygen transported
in the blood is bound to hemoglobin, while only __% is dissolved directly in plasma
98
2
Hemoglobin is a metalloprotein with four subunits composed of an ___ group attached to a ___
iron-containing heme
globin polypeptide chain.
Factors that contribute to a right shift in the oxygen
dissociation curve
increased body
temperature
decreased pH
increased 2,3-BPG
Regulation of the unloading of oxygen from the red blood cells to the target tissues is mainly by the concentration of ___ within erythrocytes
2,3-bisphosphoglycerate (2,3-BPG)
preferentially binds to and stabilizes the deoxygenated form of hemoglobin, resulting in a lower affinity of hemoglobin for oxygen
2,3-BPG
Oxygen is measured in the blood in three ways:
partial pressure of dissolved oxygen
oxygen concentration
hemoglobin saturation
Oxygen first has to dissolve in ___ before it can bind to hemoglobin
blood
The amount of dissolved O2 depends on the oxygen gradient between the ___ and ___ and the ease at which oxygen can move through the alveolar lung tissue itself
alveoli
blood
The most critical clinical test in assessing the efficacy of oxygen transportation is the ___
concentration of oxygen (CaO)
A persistent reduction in oxygen transportation capacity is most often the result of
anemia
a decrease in the total amount of hemoglobin in the blood
anemia
are an essential class of inherited disorders resulting in the defective production of hemoglobin
Thalassemias
An individual with thalassemia has a mutation that impairs the production of the ___ of hemoglobin
globin polypeptide chain
When deoxyhemoglobin polymerizes, it forms fibers that alter the shape of erythrocytes in a process known as ___
sickling
carbon monoxide poisoning
carboxyhemoglobinemia
The oxygenation process can be categorized into three stages:
oxygenation
oxygen delivery
oxygen consumption.
will result in a decreased oxygenation of
blood
Respiratory failure
the rate of oxygen transport from the lungs to the microcirculation
Oxygen delivery
Oxygen delivery is dependent on
cardiac output and arterial oxygen content
