Hemoglobin Binding in Tissues & Lungs quiz #1 Flashcards
Hemoglobin Binding in Tissues & Lungs quiz #1
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How do the conditions in muscle tissues promote the release of oxygen from hemoglobin, and what role does the Bohr effect play in this process?
In muscle tissues, cellular respiration leads to low oxygen and high concentrations of CO2 and H+. CO2 diffuses into red blood cells, where carbonic anhydrase converts it to carbonic acid, which dissociates into bicarbonate and protons, lowering pH. The high CO2 and H+ stabilize hemoglobin's T state, decreasing its affinity for oxygen and promoting oxygen release. The Bohr effect describes how increased CO2 and H+ (lower pH) decrease hemoglobin's oxygen affinity, facilitating oxygen delivery to tissues. What changes occur in the lungs that enable hemoglobin to bind oxygen efficiently, and how does this relate to hemoglobin's R state?
In the lungs, the partial pressure of oxygen is high and CO2 concentration is low due to inhalation and exhalation, respectively. The low CO2 shifts the carbonic anhydrase equilibrium to reduce H+ concentration, raising blood pH. These conditions favor the R state of hemoglobin, which has a high affinity for oxygen, allowing hemoglobin to bind oxygen efficiently and release CO2 and H+. What effect do high concentrations of CO2 and H+ in muscle tissues have on hemoglobin's oxygen affinity?
High concentrations of CO2 and H+ stabilize hemoglobin's T state, decreasing its affinity for oxygen and promoting oxygen release. How does carbonic anhydrase contribute to the release of oxygen from hemoglobin in tissues?
Carbonic anhydrase converts CO2 and water into carbonic acid, which dissociates into bicarbonate and protons, increasing H+ concentration and lowering pH, which promotes oxygen release from hemoglobin. What is the Bohr effect and how does it facilitate oxygen delivery to tissues?
The Bohr effect describes how increased CO2 and H+ (lower pH) decrease hemoglobin's oxygen affinity, facilitating oxygen release in tissues. Why does hemoglobin transition from the R state to the T state in muscle tissues?
In muscle tissues, low oxygen and high CO2/H+ concentrations cause hemoglobin to shift from the R state (high oxygen affinity) to the T state (low oxygen affinity), leading to oxygen release. What role does myoglobin play in oxygen delivery within muscle tissues?
Myoglobin, which has a higher affinity for oxygen than hemoglobin, facilitates the diffusion of oxygen into muscle tissues after hemoglobin releases it. How do the conditions in the lungs favor hemoglobin binding to oxygen?
In the lungs, high oxygen and low CO2 concentrations raise blood pH and favor the R state of hemoglobin, which has a high affinity for oxygen, enabling efficient oxygen binding. What happens to CO2 and H+ when hemoglobin binds oxygen in the lungs?
When hemoglobin binds oxygen in the lungs, it releases CO2 and H+, which are then exhaled or buffered in the blood. How does the partial pressure of oxygen differ between the lungs and muscle tissues, and what is its significance?
The partial pressure of oxygen is much higher in the lungs (~100 torr) than in muscle tissues (~20 torr), driving oxygen diffusion from the lungs into the blood and ultimately to the tissues.
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