Respiratory Physiology: Gas Transport

Questions and Answers

What percentage of oxygen is transported bound to hemoglobin?

100%

20%

98% (correct)

Oxygen dissolved in plasma contributes to the arterial oxygen partial pressure (PaO2).

True

What is the primary role of the enzyme methemoglobin reductase?

It helps keep iron in its reduced state.

Fetal hemoglobin (HgF) contains 2 alpha and 2 ______ chains.

gamma Signup and view all the answers

Match the types of hemoglobin with their chain compositions:

Adult hemoglobin (HgA) = 2 alpha and 2 beta chains Fetal hemoglobin (HgF) = 2 alpha and 2 gamma chains Signup and view all the answers

Which component of hemoglobin binds reversibly with oxygen?

Iron Signup and view all the answers

Adult hemoglobin has a higher affinity for oxygen compared to fetal hemoglobin.

False Signup and view all the answers

What is the main function of hemoglobin in red blood cells?

To transport oxygen. Signup and view all the answers

A single red blood cell contains approximately ______ million molecules of hemoglobin.

270 Signup and view all the answers

How does 2,3-bisphosphoglycerate (2,3-BPG) affect hemoglobin's affinity for oxygen?

Decreases affinity for O2 Signup and view all the answers

What is the term for hemoglobin that is not bound with oxygen?

Deoxyhemoglobin Signup and view all the answers

Cyanosis results from increased oxygenated hemoglobin.

False Signup and view all the answers

What mechanism increases hemoglobin's affinity for oxygen as it binds more molecules?

Positive cooperativity Signup and view all the answers

When hemoglobin is fully saturated with oxygen, it is referred to as __________.

oxyhemoglobin Signup and view all the answers

Match the following terms related to oxygen transport with their descriptions:

Deoxyhemoglobin = Hemoglobin not bound with oxygen Oxyhemoglobin = Hemoglobin fully saturated with oxygen Positive cooperativity = Increased affinity for oxygen with more binding Cyanosis = Condition characterized by bluish skin due to desaturated hemoglobin Signup and view all the answers

What shape does the oxyhemoglobin dissociation curve take?

Sigmoidal Signup and view all the answers

Oxygen saturation of hemoglobin increases linearly with partial pressure of oxygen (PO2).

False Signup and view all the answers

At what PO2 range does hemoglobin saturation level off, according to the oxyhemoglobin dissociation curve?

50 to 100 mmHg Signup and view all the answers

Normally, only a single O2 molecule is removed from each hemoglobin to satisfy the tissues' need for ______.

O2 Signup and view all the answers

What happens to the affinity of hemoglobin for oxygen when the first oxygen molecule binds?

Increases Signup and view all the answers

What effect does an increase in temperature have on the oxygen affinity of hemoglobin?

Decreases affinity Signup and view all the answers

A left shift in the oxygen dissociation curve indicates a decreased affinity for oxygen.

False Signup and view all the answers

What is the primary form in which carbon dioxide is carried in the blood?

Bicarbonate Signup and view all the answers

The component that increases during hypoxic conditions in red blood cells is __________.

2,3-BPG Signup and view all the answers

Match the following factors with their effects on oxygen affinity:

Higher PCO2 = Right shift Higher temperature = Right shift Higher pH = Left shift Lower 2,3-BPG = Left shift Signup and view all the answers

Which of the following conditions leads to a right shift in the oxygen dissociation curve?

Increased PCO2 Signup and view all the answers

Carbon dioxide binds to hemoglobin at the same site as oxygen.

False Signup and view all the answers

Define what P50 refers to in hemoglobin oxygen saturation.

Partial pressure of oxygen at which hemoglobin is 50% saturated. Signup and view all the answers

The percentage of carbon dioxide carried in blood as carbaminohemoglobin is __________.

23% Signup and view all the answers

In which situation would you expect hemoglobin to have a decreased affinity for oxygen?

High 2,3-BPG Signup and view all the answers

The driving gradient for O2 is __, and the driving gradient for CO2 is . Any changes to these gradients indicates : . (Answer in complete sentence)

The driving gradient for O2 is 60mmHg, and the driving gradient for CO2 is 6 mmHg. Any changes to these gradients indicates pathologies! Signup and view all the answers

Gas exchange at the levels of the tissues has the same pattern as gas exchange in capillaries. There is more O2 in the _____ than the _, so O2 moves into the _. There is more CO2 in the than the , so CO2 moves into the _____.

There is more O2 in the blood than the tissues, so O2 moves into the tissue. There is more CO2 in the blood than the tissues, so CO2 moves into the blood. Signup and view all the answers

O2 carried by the RBC depend on two things. These are …..

it depends on hemoglobin content in the blood and the partial pressure of O2 in the plasma Signup and view all the answers

When oxygen is unloading into the Tissues we _________ (increase or decrease) the affinity?

Oxygen unloading into the tissues decreases the affinity Signup and view all the answers

Study Notes

Gas Transport in the Blood

Oxygen Transport

Oxygen's solubility in plasma is low, with only 2% dissolved and 98% bound to hemoglobin.
Normal tissue requires approximately 5 ml/dL of O2, of which only 0.3 ml/dL is dissolved.
Hemoglobin is a globular protein composed of four subunits, each containing a heme group for iron binding.
Each red blood cell contains about 270 million hemoglobin molecules, facilitating oxygen transport.

Hemoglobin Structure

Hemoglobin consists of heme (iron-binding protoporphyrin) and globin chains (either alpha or beta).
The sequence of amino acids in globin is crucial for oxygen binding capabilities.
Heme's ferrous iron (Fe2+) can reversibly bond with a single O2 molecule, preventing oxidative damage by ferric iron (Fe3+).

Types of Hemoglobin

Adult hemoglobin (HbA) contains 2 alpha and 2 beta chains; fetal hemoglobin (HbF) contains 2 alpha and 2 gamma chains.
HbF displays a higher affinity for O2 to facilitate oxygen transfer from mother to fetus.
2,3-BPG reduces HbA's oxygen affinity, while it has a lesser effect on HbF.

Oxyhemoglobin Dynamics

Hemoglobin can bind up to 4 oxygen molecules, transitioning from deoxygenated (deoxyhemoglobin) to oxygenated (oxyhemoglobin).
Oxyhemoglobin saturation does not increase linearly with partial pressure of O2 (PO2); it exhibits a sigmoidal curve due to positive cooperativity.
O2 release is influenced by various factors including temperature, pH, PCO2, and 2,3-BPG concentration.

Oxyhemoglobin Dissociation Curve

The curve steepens from a PO2 of 0 to 40 mmHg and levels off between 50 to 100 mmHg, indicating high saturation.
In normal conditions, hemoglobin releases approximately one O2 molecule per cycle to meet tissue demands.

Factors Affecting O2 Affinity

Right shift: Occurs at higher temperatures, lower pH, higher PCO2, and higher 2,3-BPG levels, enhancing O2 release in metabolically active tissues.
Left shift: Occurs at lower temperatures, higher pH, lower PCO2, and lower 2,3-BPG levels, making O2 release more difficult.

Carbon Dioxide Transport

CO2 is transported in the blood in three main forms: 23% bound to hemoglobin (carbaminohemoglobin), 70% as bicarbonate in plasma, and 7% freely dissolved in plasma.
CO2 binds with hemoglobin's amino groups, forming carbaminohemoglobin, without competing with oxygen binding sites.

Summary of Transport Mechanisms

Efficient O2 transport relies on hemoglobin's structural properties and the influence of local metabolic conditions.
Understanding the dynamics of both O2 and CO2 transport is crucial for comprehending respiratory physiology.

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Description

This quiz explores the mechanisms of gas transport in the blood, focusing on oxygen transport and its solubility in plasma. It provides insights into the different forms in which oxygen is carried in the bloodstream. Perfect for students studying veterinary physiology or related fields.

Respiratory Physiology: Gas Transport

Questions and Answers

What percentage of oxygen is transported bound to hemoglobin?

Oxygen dissolved in plasma contributes to the arterial oxygen partial pressure (PaO2).

What is the primary role of the enzyme methemoglobin reductase?

Fetal hemoglobin (HgF) contains 2 alpha and 2 ______ chains.

Match the types of hemoglobin with their chain compositions:

Which component of hemoglobin binds reversibly with oxygen?

Adult hemoglobin has a higher affinity for oxygen compared to fetal hemoglobin.

What is the main function of hemoglobin in red blood cells?

A single red blood cell contains approximately ______ million molecules of hemoglobin.

How does 2,3-bisphosphoglycerate (2,3-BPG) affect hemoglobin's affinity for oxygen?

What is the term for hemoglobin that is not bound with oxygen?

Cyanosis results from increased oxygenated hemoglobin.

What mechanism increases hemoglobin's affinity for oxygen as it binds more molecules?

When hemoglobin is fully saturated with oxygen, it is referred to as __________.

Match the following terms related to oxygen transport with their descriptions:

What shape does the oxyhemoglobin dissociation curve take?

Oxygen saturation of hemoglobin increases linearly with partial pressure of oxygen (PO2).

At what PO2 range does hemoglobin saturation level off, according to the oxyhemoglobin dissociation curve?

Normally, only a single O2 molecule is removed from each hemoglobin to satisfy the tissues' need for ______.

What happens to the affinity of hemoglobin for oxygen when the first oxygen molecule binds?

What effect does an increase in temperature have on the oxygen affinity of hemoglobin?

A left shift in the oxygen dissociation curve indicates a decreased affinity for oxygen.

What is the primary form in which carbon dioxide is carried in the blood?

The component that increases during hypoxic conditions in red blood cells is __________.

Match the following factors with their effects on oxygen affinity:

Which of the following conditions leads to a right shift in the oxygen dissociation curve?

Carbon dioxide binds to hemoglobin at the same site as oxygen.

Define what P50 refers to in hemoglobin oxygen saturation.

The percentage of carbon dioxide carried in blood as carbaminohemoglobin is __________.

In which situation would you expect hemoglobin to have a decreased affinity for oxygen?

The driving gradient for O2 is ______, and the driving gradient for CO2 is ____. Any changes to these gradients indicates : ____. (Answer in complete sentence)

Gas exchange at the levels of the tissues has the same pattern as gas exchange in capillaries. There is more O2 in the _________ than the _______, so O2 moves into the _______. There is more CO2 in the ________ than the ______, so CO2 moves into the _______.

O2 carried by the RBC depend on two things. These are …..

When oxygen is unloading into the Tissues we _________ (increase or decrease) the affinity?

Study Notes

Gas Transport in the Blood

Oxygen Transport

Hemoglobin Structure

Types of Hemoglobin

Oxyhemoglobin Dynamics

Oxyhemoglobin Dissociation Curve

Factors Affecting O2 Affinity

Carbon Dioxide Transport

Summary of Transport Mechanisms

Studying That Suits You

Description

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