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What is the primary factor affecting the amount of oxygen carried by hemoglobin?
Anemia does not affect oxygen transport in the bloodstream.
False
What effect does an increase in metabolism have on hemoglobin's affinity for oxygen?
It decreases hemoglobin's affinity for oxygen.
Hemoglobin carries _____ times more dissolved oxygen than carbon dioxide.
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Match the following forms of CO2 transport in the blood with their percentage of total content:
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What percentage of oxygen in the blood is reversibly bound to hemoglobin?
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At a usual arterial pressure of 100 mm Hg, 3 ml of O2 is dissolved in each liter of blood.
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What is the significance of hemoglobin's ability to bind 4 molecules of oxygen?
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What regulates the contraction of respiratory muscles?
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The amount of gas dissolved is directly proportional to ____________ of that gas.
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What happens to oxygen saturation as blood passes through tissue capillaries?
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True or False: The rhythmic nature of breathing originates solely from chemoreceptors.
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What is the most important factor that leads to an increase in ventilation?
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Match the following terms related to oxygen transport with their descriptions:
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Hypoxia is a deficit in O2 supply to the ______.
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What does a 100% saturation of hemoglobin indicate?
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A greyhound consumes 4500 ml of O2 per minute during rest.
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Match the following respiratory components with their functions:
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Which of the following symptoms is NOT associated with hypoxia?
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True or False: In birds, both inspiration and expiration are passive processes.
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What is the remedy for hypoxia?
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Study Notes
Oxygen Transport in Blood
- Most of the oxygen in blood (>97%) is bound to hemoglobin
- Oxygen dissolved in blood follows Henry’s Law: amount of gas dissolved is directly proportional to partial pressure of that gas
- Solubility of O2 very low in blood
- At a usual arterial pressure (PaO2=100mm Hg): 3 ml of O2 per L of blood is dissolved
- Blood leaving the lungs contains ~200 ml O2 per liter, 197 ml/liter is bound to hemoglobin
- Hemoglobin contains 4 heme groups, each with 1 iron atom that can bind 1 molecule of O2
- Oxygen saturation is the amount of oxygen carried divided by the total oxygen capacity of blood
- When all 4 binding sites of hemoglobin are occupied: 100% saturation
- When half the binding sites are occupied: 50% saturation
Factors Affecting Hb Saturation
- pH: increase in H+ decreases affinity of Hb for O2, curve shifts to the right, need higher pO2 for saturation, unloading occurs more rapidly
- Temperature: increase in metabolism = increase in heat, similar effect as pH
- 2,3DPG (diphosphoglycerate): binds to Hb, similar effect as pH
- The pO2 in the lung is generally sufficient to maintain 100% saturation, pH, T and DPG mainly affect the unloading of oxygen
Blood Transport of CO2
- Carbon dioxide in blood is carried in three forms: physical solution, carbamino compounds, and bicarbonate
- Physical solution (5-10%) = dissolved in blood
- Carbamino compounds (bound to proteins) bind to –NH groups on proteins, especially hemoglobin, stronger affinity for deoxyhemoglobin
- Bicarbonate (HCO3-), 70%-75% of total carbon dioxide content, CO2 + H2O H2CO3 HCO3- + H+
Regulation of Respiration
- Respiratory muscles contract rhythmically
- Respiratory center in the brain stem (medulla oblongata) originates rhythmic nature of breathing
- Inspiratory neurons stimulate motor neurons in the spinal cord contraction of respiratory muscles
- Inspiratory neurons are controlled by Central Pattern Generator (CPG)
- Respiratory center is influenced by pO2, pCO2 and H+ concentrations
- Stretch receptor in lung, bronchiole, and muscles influence Inspiratory neurons
Chemoreceptors
- Chemoreceptors detect O2, CO2 and H+
- Central chemoreceptors: in brain stem, indirectly detect changes in pCO2 in the blood
- Peripheral chemoreceptors: in carotid and the aorta, detect direct arterial changes in pO2, pCO2 and H+
- Information sent to the respiratory centers: pCO2, H+ or pO2 increase ventilation
- pCO2 most important factor leads to increase in H+
Hypoxia
- Deficit in O2 supply to the cells
- Symptoms: confusion, hallucination, loss of consciousness
- Causes: low arterial pO2 from pulmonary diseases/failure, high altitude, reduced transport capacity, reduced blood flow to tissues, impaired cell metabolism
- Remedy: inhalation pure O2
Respiration in Birds
- Gas exchange identical to mammals
- Ventilation different
- Lungs relatively small and rigid; do not change in volume during inspiration/expiration
- Air sacs communicate with the lungs and the bronchi
- Inspiration and expiration are active processes
- Possess unidirectional parabronchi that runs in the lung.
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Description
This quiz explores the mechanisms of oxygen transport in blood, focusing on hemoglobin's role in carrying oxygen. Learn about factors affecting hemoglobin saturation, such as pH and temperature, and understand how these factors influence oxygen delivery in the body. Test your knowledge on key concepts like Henry's Law and the solubility of O2 in blood.
