Hemoglobin Structure and Function Quiz
127 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which type of hemoglobin is the most prevalent form found in adults?

  • Hemoglobin F
  • Hemoglobin A2
  • Hemoglobin A (correct)
  • Hemoglobin S

What percentage of oxygen in the blood is carried by hemoglobin?

  • 100%
  • 2%
  • 50%
  • 98% (correct)

What component of hemoglobin binds oxygen?

  • Alpha chains
  • Globin chains
  • Porphyrin ring
  • Heme (correct)

Which hemoglobin type is found predominantly in fetuses?

<p>Hemoglobin F (B)</p> Signup and view all the answers

How are the chains in hemoglobin structured?

<p>Two pairs of globin chains (C)</p> Signup and view all the answers

According to Henry's law, what determines the amount of dissolved oxygen in plasma?

<p>The partial pressure of oxygen (D)</p> Signup and view all the answers

What is the role of the porphyrin ring in hemoglobin?

<p>To facilitate oxygen binding (B)</p> Signup and view all the answers

Which hemoglobin type is less common and makes up about 2 to 3% of adult hemoglobin?

<p>Hemoglobin A2 (D)</p> Signup and view all the answers

What phenomenon increases the affinity of hemoglobin for subsequent oxygen molecules after one binds?

<p>Positive cooperativity (A)</p> Signup and view all the answers

Which form of hemoglobin is favored in tissues to facilitate oxygen release?

<p>Taut form (B)</p> Signup and view all the answers

What does the S-shaped oxygen hemoglobin dissociation curve primarily illustrate?

<p>Nonlinear binding behavior (A)</p> Signup and view all the answers

At a partial pressure of oxygen of 100 mmHg, how saturated is hemoglobin in the lungs?

<p>100% (B)</p> Signup and view all the answers

What is the primary reason the binding affinity of the fourth oxygen molecule to hemoglobin is significantly higher than that of the first?

<p>Positive cooperativity (C)</p> Signup and view all the answers

What is the expected state of hemoglobin after it has released some oxygen in the body's tissues?

<p>Mixture of taut and relaxed forms (C)</p> Signup and view all the answers

What does the term 'allosteric' refer to in the context of hemoglobin's functionality?

<p>Multi-subunit interactions (D)</p> Signup and view all the answers

What happens to the oxygen hemoglobin dissociation curve when environmental conditions favor the taut form?

<p>It shifts to the right (A)</p> Signup and view all the answers

The concept of the 'oxygen saturation' of hemoglobin is best described as:

<p>The percentage of hemoglobin binding sites occupied by oxygen (A)</p> Signup and view all the answers

What condition in the bloodstream is associated with a normal partial pressure of oxygen of about 40 mmHg?

<p>Venous blood (B)</p> Signup and view all the answers

How many oxygen molecules can one hemoglobin molecule bind in total?

<p>Four (B)</p> Signup and view all the answers

Which of the following is an example of a negative allosteric effect?

<p>Decreased binding of oxygen with increased carbon dioxide (D)</p> Signup and view all the answers

What requires a shift in the oxygen hemoglobin dissociation curve to occur?

<p>Variable environmental factors (B)</p> Signup and view all the answers

What is the primary role of 2,3-BPG in red blood cells?

<p>Promotes oxygen release from hemoglobin (A)</p> Signup and view all the answers

What physiological state leads to an increase in 2,3-BPG levels in red blood cells?

<p>Chronic hypoxia (A)</p> Signup and view all the answers

How does the presence of 2,3-BPG affect the oxygen hemoglobin dissociation curve?

<p>Shifts it to the right (D)</p> Signup and view all the answers

Which patient condition is likely to lead to increased levels of 2,3-BPG?

<p>Chronic anemia (C)</p> Signup and view all the answers

Fetal hemoglobin differs from adult hemoglobin primarily due to its:

<p>Altered structure of globin chains (A)</p> Signup and view all the answers

What is the consequence of fetal hemoglobin's lower binding capacity for 2,3-BPG?

<p>Increased oxygen delivery to tissues (D)</p> Signup and view all the answers

What shift in the oxygen hemoglobin dissociation curve is caused by increasing CO2 levels?

<p>Right shift (D)</p> Signup and view all the answers

Which of the following statements about myoglobin is correct?

<p>It has a hyperbolic oxygen saturation curve. (B)</p> Signup and view all the answers

What is the typical oxygen partial pressure in the alveoli at sea level?

<p>100 mm Hg (A)</p> Signup and view all the answers

What is the effect of increased temperature on the oxygen hemoglobin dissociation curve?

<p>Shifts it to the right (A)</p> Signup and view all the answers

Which of the following best describes the reason for fetal hemoglobin's greater oxygen affinity?

<p>Reduced binding of 2,3-BPG (D)</p> Signup and view all the answers

Which of the following aids in delivering more oxygen in a high-altitude setting?

<p>Higher levels of 2,3-BPG (A)</p> Signup and view all the answers

Under which condition would myoglobin most likely be ineffective?

<p>When rapid oxygen unloading is required (A)</p> Signup and view all the answers

What is the primary factor contributing to the right shift of the oxygen hemoglobin dissociation curve?

<p>Increased levels of lactic acid (D)</p> Signup and view all the answers

What is the primary effect of a rightward shift in the hemoglobin dissociation curve?

<p>It significantly enhances oxygen unloading at tissues. (A)</p> Signup and view all the answers

Which of the following conditions is NOT associated with a rightward shift of the hemoglobin dissociation curve?

<p>Increased alkalinity. (D)</p> Signup and view all the answers

When comparing normal conditions to conditions with a rightward shift, what happens to hemoglobin saturation at a partial pressure of oxygen of 40 mmHg?

<p>It decreases to 50%. (C)</p> Signup and view all the answers

What is the P50 in the context of the hemoglobin dissociation curve?

<p>The pressure at which hemoglobin is 50% saturated. (D)</p> Signup and view all the answers

Which molecule primarily promotes oxygen release from hemoglobin in red blood cells?

<p>2,3-bisphosphoglycerate (2,3-BPG). (D)</p> Signup and view all the answers

How does a rightward shift in the hemoglobin oxygen dissociation curve affect the delivery of oxygen to tissues?

<p>It enhances oxygen delivery to active tissues. (D)</p> Signup and view all the answers

What typically occurs to the pH level in red blood cells when carbon dioxide levels rise?

<p>The pH level falls. (C)</p> Signup and view all the answers

What is a mnemonic to remember the implications of a rightward shift in the oxygen dissociation curve?

<p>Right means release oxygen and favors the taut form. (B)</p> Signup and view all the answers

When the hemoglobin oxygen dissociation curve shifts left, what is the effect on oxygen release?

<p>Less oxygen is released in tissues. (D)</p> Signup and view all the answers

What physiological changes cause the hemoglobin saturation to shift to the right?

<p>Higher CO2 levels and lower pH. (B)</p> Signup and view all the answers

What role does temperature play in the right shift of the hemoglobin dissociation curve?

<p>Higher temperatures promote the release of oxygen. (A)</p> Signup and view all the answers

What is the effect of 2,3-BPG on the affinity of hemoglobin for oxygen?

<p>It decreases hemoglobin's affinity for oxygen. (B)</p> Signup and view all the answers

What physiological state is indicated by a leftward shift in the hemoglobin dissociation curve?

<p>Decreased carbon dioxide levels. (B)</p> Signup and view all the answers

What is the primary problem with hemoglobin when carbon monoxide binds to it?

<p>It decreases available binding sites for oxygen. (C)</p> Signup and view all the answers

What effect does carbon monoxide have on the hemoglobin oxygen dissociation curve?

<p>It shifts the curve to the left. (B)</p> Signup and view all the answers

What is the typical presentation for a patient with carbon monoxide poisoning?

<p>Cherry red lips and headache. (A)</p> Signup and view all the answers

What is the primary treatment for carbon monoxide poisoning?

<p>High-pressure oxygen therapy. (D)</p> Signup and view all the answers

Which condition involves an excess of Fe3+ in hemoglobin?

<p>Methemoglobinemia. (D)</p> Signup and view all the answers

Which of the following drugs is commonly associated with causing methemoglobinemia?

<p>Benzocaine. (B)</p> Signup and view all the answers

What is a distinguishing feature of blood in a patient with methemoglobinemia?

<p>Chocolate brown appearance. (A)</p> Signup and view all the answers

Why might pulse oximetry readings be misleading in cases of methemoglobinemia?

<p>It can't differentiate between methemoglobin and oxyhemoglobin. (C)</p> Signup and view all the answers

In methemoglobinemia, what is the effect of administering oxygen to the patient?

<p>It has no therapeutic effect. (C)</p> Signup and view all the answers

What blood gas result is typically normal in cases of methemoglobinemia?

<p>Normal PaO2. (C)</p> Signup and view all the answers

What is the function of methylene blue in the treatment of methemoglobinemia?

<p>To convert Fe3+ back to Fe2+. (B)</p> Signup and view all the answers

What is the normal carboxyhemoglobin level in a non-smoker?

<p>Less than 3%. (A)</p> Signup and view all the answers

Which physiological state does a leftward shift in the hemoglobin oxygen dissociation curve indicate?

<p>Increased affinity for oxygen. (B)</p> Signup and view all the answers

Which of the following conditions can lead to functional anemia despite normal hemoglobin levels?

<p>Carbon monoxide poisoning. (B)</p> Signup and view all the answers

The X-axis of the plot represents the partial pressure of ______ in the bloodstream.

<p>oxygen</p> Signup and view all the answers

An S-shaped curve in the oxygen hemoglobin dissociation plot indicates a special type of ______ in hemoglobin binding.

<p>cooperativity</p> Signup and view all the answers

Hemoglobin can bind a maximum of ______ molecules of oxygen.

<p>four</p> Signup and view all the answers

The phenomenon where the binding of one molecule of oxygen increases the likelihood of others binding is called ______ cooperativity.

<p>positive</p> Signup and view all the answers

In the lungs, the partial pressure of oxygen is about ______.

<p>100</p> Signup and view all the answers

At a lower PO2 of about 40, hemoglobin is approximately ______% saturated with oxygen in the tissues.

<p>75</p> Signup and view all the answers

Hemoglobin exists in two forms: the taut form and the ______ form.

<p>relaxed</p> Signup and view all the answers

The changes in environmental conditions can shift the oxygen hemoglobin dissociation curve to the ______ or left.

<p>right</p> Signup and view all the answers

When the affinity for oxygen increases due to cooperative binding, the curve becomes ______-shaped.

<p>S</p> Signup and view all the answers

Hemoglobin is considered an ______ protein because its binding properties change with environmental factors.

<p>allosteric</p> Signup and view all the answers

A ______ shift in the hemoglobin dissociation curve indicates a decrease in affinity for oxygen.

<p>rightward</p> Signup and view all the answers

The ______ effect describes how hemoglobin's binding at one site influences other binding sites.

<p>allosteric</p> Signup and view all the answers

In conditions where the taut form is favored, hemoglobin is more likely to ______ oxygen.

<p>release</p> Signup and view all the answers

Increased ______ levels can lead to a rightward shift of the oxygen hemoglobin dissociation curve.

<p>CO2</p> Signup and view all the answers

Hemoglobin carries about ______% of the oxygen in our plasma.

<p>98</p> Signup and view all the answers

The heme group in hemoglobin contains an ______ at its center that binds oxygen.

<p>iron</p> Signup and view all the answers

Hemoglobin A is made up of two alpha chains and two ______ chains.

<p>beta</p> Signup and view all the answers

The fetal type of hemoglobin is known as ______.

<p>hemoglobin F</p> Signup and view all the answers

According to Henry's law, the amount of dissolved oxygen is proportional to the partial pressure of ______.

<p>oxygen</p> Signup and view all the answers

Hemoglobin A2 is a less common adult type of hemoglobin that constitutes about ______% of adult hemoglobin.

<p>2 to 3</p> Signup and view all the answers

The porphyrin ring surrounding the iron in heme structure is crucial for binding ______.

<p>oxygen</p> Signup and view all the answers

All hemoglobin molecules are made up of four chains in two ______.

<p>pairs</p> Signup and view all the answers

Under normal circumstances, the partial pressure of oxygen in the lungs is about a hundred, causing hemoglobin to be a hundred percent ______.

<p>saturated</p> Signup and view all the answers

When hemoglobin reaches the tissues, the PaO2 is much lower at ______.

<p>40</p> Signup and view all the answers

A right shift in the oxygen hemoglobin dissociation curve allows hemoglobin to fall from a hundred to ______ instead of a hundred to 75.

<p>50</p> Signup and view all the answers

The right shift is noted to favor the ______ form of hemoglobin, promoting oxygen release.

<p>taut</p> Signup and view all the answers

An increase in carbon dioxide levels is sensed by hemoglobin, leading to a ______ shift in the curve.

<p>rightward</p> Signup and view all the answers

When the pH inside red cells falls, this can also cause hemoglobin to shift to the ______.

<p>right</p> Signup and view all the answers

The P50 is the partial pressure at which hemoglobin is ______ saturated.

<p>50%</p> Signup and view all the answers

A rise in body ______ can also lead to a rightward shift in the hemoglobin dissociation curve.

<p>temperature</p> Signup and view all the answers

2,3-bisphosphoglycerate, or ______, promotes oxygen release from hemoglobin.

<p>2,3-BPG</p> Signup and view all the answers

Increased metabolic activity leads to higher levels of ______ in red blood cells.

<p>2,3-BPG</p> Signup and view all the answers

Left shifts occur when there's ______ metabolic activity, causing hemoglobin to hold onto oxygen.

<p>lower</p> Signup and view all the answers

The ______ formed in glycolysis is converted to 2,3-BPG in red blood cells.

<p>1,3-BPG</p> Signup and view all the answers

Rightward shifts of the hemoglobin dissociation curve favor ______ of oxygen in tissues.

<p>release</p> Signup and view all the answers

A mnemonic to remember right shifts starts with 'R' for ______ oxygen.

<p>release</p> Signup and view all the answers

When the oxygen hemoglobin dissociation curve shifts left, it is less likely to ______ oxygen.

<p>release</p> Signup and view all the answers

1,3-BPG is a glycolysis ______ and red cells have an enzyme called BPG-mutase.

<p>intermediate</p> Signup and view all the answers

Red cells sacrifice a little bit of ______ to make 2,3-BPG.

<p>ATP</p> Signup and view all the answers

2,3-BPG causes hemoglobin to ______ of oxygen.

<p>let go</p> Signup and view all the answers

Patients with COPD can have high levels of ______.

<p>2,3-BPG</p> Signup and view all the answers

At high altitude, the PaO2 in the alveoli is much ______.

<p>lower</p> Signup and view all the answers

The presence of 2,3-BPG shifts the oxygen hemoglobin ______ curve to the right.

<p>dissociation</p> Signup and view all the answers

Fetal hemoglobin is composed of two alpha and two ______ chains.

<p>gamma</p> Signup and view all the answers

Fetal hemoglobin has a higher oxygen ______ than hemoglobin A.

<p>affinity</p> Signup and view all the answers

In fetal hemoglobin, 2,3-BPG binds less effectively to the ______ chains.

<p>gamma</p> Signup and view all the answers

Myoglobin can only bind one molecule of ______.

<p>oxygen</p> Signup and view all the answers

Higher levels of CO2 cause a ______ shift in the oxygen hemoglobin dissociation curve.

<p>rightward</p> Signup and view all the answers

The oxygen saturation curve for myoglobin is ______ shaped compared to hemoglobin's S-shape.

<p>linear</p> Signup and view all the answers

In adult hemoglobin, 2,3-BPG binds well to the ______ globin chains.

<p>beta</p> Signup and view all the answers

The oxygen partial pressure in a normal adult is about ______ mmHg.

<p>90</p> Signup and view all the answers

Carbon monoxide binds to iron in heme with ______ times the affinity of oxygen.

<p>240</p> Signup and view all the answers

The structure formed when carbon monoxide binds to hemoglobin is called ______.

<p>carboxyhemoglobin</p> Signup and view all the answers

Patients exposed to carbon monoxide poisoning may exhibit ______ lips, a unique symptom.

<p>cherry red</p> Signup and view all the answers

A normal carboxyhemoglobin level is less than ______ percent.

<p>3</p> Signup and view all the answers

Methemoglobinemia occurs when there is an excess of hemoglobin in the ______ state.

<p>Fe3+</p> Signup and view all the answers

Local anesthetics, such as ______, are known to potentially cause methemoglobinemia.

<p>benzocaine</p> Signup and view all the answers

The treatment for methemoglobinemia involves using a reducing agent called ______.

<p>methylene blue</p> Signup and view all the answers

A classic finding in patients with methemoglobinemia is the presence of ______ brown blood.

<p>chocolate</p> Signup and view all the answers

Pulse oximetry readings in methemoglobinemia can be misleading because they may show normal ______.

<p>results</p> Signup and view all the answers

One of the conditions that can lead to methemoglobinemia is inhalation of ______ oxide.

<p>nitric</p> Signup and view all the answers

In cases of carbon monoxide poisoning, the ______ oximeter often appears normal.

<p>pulse</p> Signup and view all the answers

Carbon monoxide causes a leftward shift in the ______ curve of hemoglobin.

<p>oxygen dissociation</p> Signup and view all the answers

Patients with carbon monoxide poisoning often report symptoms such as headache, ______, nausea, or dizziness.

<p>malaise</p> Signup and view all the answers

In normal conditions, hemoglobin releases oxygen more readily at lower ______ pressures.

<p>partial</p> Signup and view all the answers

Flashcards

Hemoglobin's role in oxygen transport

Hemoglobin carries about 98% of the oxygen in blood, enabling efficient delivery to body cells.

Oxygen dissolved in plasma

A small amount of oxygen dissolves directly into the blood's liquid component (plasma), dictated by Henry's law.

Hemoglobin structure

Hemoglobin consists of four globin chains (alpha, beta, gamma, delta) and four heme groups.

Hemoglobin A

Adult hemoglobin, the most common type in adults, composed of two alpha and two beta chains.

Signup and view all the flashcards

Hemoglobin A2

Adult hemoglobin, less common than A, composed of two alpha and two delta chains.

Signup and view all the flashcards

Hemoglobin F

Fetal hemoglobin, found in babies, composed of two alpha and two gamma chains.

Signup and view all the flashcards

Heme group

The iron-containing component of hemoglobin crucial for oxygen binding.

Signup and view all the flashcards

Oxygen-hemoglobin dissociation curve

A graph showing the relationship between the partial pressure of oxygen and the percentage of hemoglobin saturated with oxygen.

Signup and view all the flashcards

S-shaped Curve

The characteristic shape of the oxygen-hemoglobin dissociation curve, reflecting the cooperative binding of oxygen to hemoglobin.

Signup and view all the flashcards

Positive Cooperativity

The phenomenon where the binding of one oxygen molecule to hemoglobin increases the affinity of hemoglobin for subsequent oxygen molecules.

Signup and view all the flashcards

Allosteric protein

Protein whose activity is affected by binding to a site other than the active site.

Signup and view all the flashcards

Partial Pressure of Oxygen (PO2)

A measure of the concentration of oxygen in the blood.

Signup and view all the flashcards

Taut Form

A conformation of hemoglobin that releases oxygen more readily.

Signup and view all the flashcards

Relaxed Form

A conformation of hemoglobin that holds onto oxygen more tightly.

Signup and view all the flashcards

Rightward Shift

A shift of the oxygen-hemoglobin dissociation curve to the right, indicating decreased oxygen affinity.

Signup and view all the flashcards

Leftward Shift

A shift of the oxygen-hemoglobin dissociation curve to the left, indicating increased oxygen affinity.

Signup and view all the flashcards

Lungs

Where hemoglobin becomes saturated with oxygen.

Signup and view all the flashcards

Tissues

Where hemoglobin releases oxygen.

Signup and view all the flashcards

Oxygen Unloading

The process of releasing oxygen from hemoglobin in tissues.

Signup and view all the flashcards

Oxygen Loading

The process of taking up oxygen by hemoglobin in the lungs.

Signup and view all the flashcards

What is a right shift?

A right shift of the hemoglobin-oxygen dissociation curve indicates that hemoglobin releases more oxygen to tissues.

Signup and view all the flashcards

How does a right shift affect oxygen saturation?

In a right shift, hemoglobin reaches a lower saturation level in the tissues even with the same partial pressure of oxygen.

Signup and view all the flashcards

What is the effect of increased CO2 on the curve?

Elevated CO2 levels cause a right shift, promoting oxygen release.

Signup and view all the flashcards

How does pH affect the curve?

Low pH (acidic) causes a right shift, aiding oxygen delivery.

Signup and view all the flashcards

What's the impact of temperature on the curve?

Higher temperature results in a right shift, meaning more oxygen release.

Signup and view all the flashcards

What is P50?

The partial pressure of oxygen at which hemoglobin is 50% saturated.

Signup and view all the flashcards

How does a right shift affect P50?

A right shift increases the P50 value.

Signup and view all the flashcards

What is a left shift?

A left shift of the hemoglobin-oxygen dissociation curve indicates that hemoglobin holds on to oxygen more tightly.

Signup and view all the flashcards

How does a left shift affect oxygen saturation?

In a left shift, hemoglobin reaches a higher saturation level in the tissues even with the same partial pressure of oxygen.

Signup and view all the flashcards

What causes a left shift?

Lower CO2 levels, higher pH, and lower temperatures can induce a left shift.

Signup and view all the flashcards

What is 2,3-BPG?

2,3-bisphosphoglycerate is a molecule found in red blood cells that promotes oxygen release from hemoglobin.

Signup and view all the flashcards

How does 2,3-BPG affect oxygen affinity?

High levels of 2,3-BPG decrease the affinity of hemoglobin for oxygen, enhancing oxygen delivery to tissues.

Signup and view all the flashcards

Where does 2,3-BPG come from?

2,3-BPG is produced from 1,3-BPG, an intermediate in glycolysis.

Signup and view all the flashcards

2,3-BPG

A molecule produced by red blood cells that decreases hemoglobin's affinity for oxygen, helping to release oxygen into tissues.

Signup and view all the flashcards

Chronic Hypoxia

A prolonged state of low oxygen levels in the body, often triggered by conditions like COPD, high altitude, or anemia.

Signup and view all the flashcards

2,3-BPG's Role in Hypoxia

In chronic hypoxia, red blood cells produce more 2,3-BPG to increase oxygen release, ensuring tissues receive adequate oxygen.

Signup and view all the flashcards

High Altitude & Oxygen Saturation

At high altitude, the lower PaO2 in alveoli leads to less oxygen saturation of hemoglobin, reducing oxygen delivery to tissues.

Signup and view all the flashcards

Right Shift of Oxygen Dissociation Curve

A shift in the curve to the right means hemoglobin releases oxygen more easily (lower affinity).

Signup and view all the flashcards

Shifting the Curve

Factors like increased CO2, low pH, high temperature, and high 2,3-BPG levels shift the oxygen dissociation curve to the right, while a decrease in these factors shifts it to the left.

Signup and view all the flashcards

Fetal Hemoglobin (HbF)

The primary type of hemoglobin in fetuses, characterized by a higher oxygen affinity than adult hemoglobin (HbA).

Signup and view all the flashcards

HbF's Function

HbF's higher oxygen affinity allows it to pull oxygen from maternal HbA, ensuring the fetus receives adequate oxygen.

Signup and view all the flashcards

Left Shift of Oxygen Dissociation Curve

A shift to the left means hemoglobin binds oxygen more tightly (higher affinity).

Signup and view all the flashcards

HbF's Affinity for 2,3-BPG

HbF has a lower affinity for 2,3-BPG than HbA, contributing to its higher oxygen affinity.

Signup and view all the flashcards

Myoglobin

A protein found in skeletal muscles and the heart that binds oxygen, but has a higher affinity for oxygen than hemoglobin.

Signup and view all the flashcards

Myoglobin's Oxygen Saturation Curve

Myoglobin has a hyperbolic oxygen saturation curve, unlike the sigmoidal shape of hemoglobin's curve.

Signup and view all the flashcards

Myoglobin vs. Hemoglobin for Oxygen Delivery

Hemoglobin is more efficient than myoglobin for oxygen delivery to tissues because hemoglobin releases oxygen more readily at lower oxygen partial pressures.

Signup and view all the flashcards

Hemoglobin's Advantage over Myoglobin

Hemoglobin's ability to release oxygen at lower oxygen partial pressures enables efficient delivery throughout the body, unlike myoglobin, which tends to hold onto oxygen even when it's needed.

Signup and view all the flashcards

Oxygen Delivery for Metabolism

Oxygen is essential for cellular metabolism, providing the final electron acceptor in the electron transport chain, driving ATP production.

Signup and view all the flashcards

Carbon monoxide poisoning

Carbon monoxide binds to hemoglobin's iron with 240 times the affinity of oxygen. This prevents oxygen binding, causing functional anemia.

Signup and view all the flashcards

Carboxyhemoglobin

Hemoglobin molecule with carbon monoxide bound to its heme group, reducing oxygen carrying capacity.

Signup and view all the flashcards

Functional anemia

A condition mimicking anemia where hemoglobin is present but unable to carry oxygen efficiently due to a factor like carbon monoxide.

Signup and view all the flashcards

Allosteric modifier

A substance that binds to a protein at a site different from the active site, altering its conformation and function.

Signup and view all the flashcards

Leftward shift in oxygen-hemoglobin dissociation curve

A shift in the curve indicating that hemoglobin binds oxygen more tightly and releases it less readily.

Signup and view all the flashcards

Cherry red lips

A rare sign of carbon monoxide poisoning, caused by the red color of carboxyhemoglobin.

Signup and view all the flashcards

Pulse oximeter limitation

Pulse oximeters can't distinguish between oxyhemoglobin and carboxyhemoglobin, leading to false-positive oxygen saturation readings.

Signup and view all the flashcards

Carboxyhemoglobin level

A blood test measuring the percentage of hemoglobin bound to carbon monoxide.

Signup and view all the flashcards

Methemoglobinemia

A condition where a significant amount of hemoglobin is in the Fe3+ state, unable to bind oxygen.

Signup and view all the flashcards

Causes of methemoglobinemia

Certain drugs like benzocaine, nitric oxide, and dapsone can oxidize iron in hemoglobin to Fe3+ state.

Signup and view all the flashcards

Methylene blue

A reducing agent used to treat methemoglobinemia by converting Fe3+ back to Fe2+.

Signup and view all the flashcards

Chocolate brown blood

A characteristic sign of methemoglobinemia, caused by the brown color of methemoglobin.

Signup and view all the flashcards

Oxygen saturation unreliability in methemoglobinemia

Pulse oximeters may give misleadingly high or low oxygen saturation readings in methemoglobinemia due to issues with the Fe3+ state.

Signup and view all the flashcards

PaO2 in methemoglobinemia

Arterial partial pressure of oxygen (PaO2) will be normal in methemoglobinemia because the problem is not getting oxygen into the blood, but the hemoglobin's inability to bind it.

Signup and view all the flashcards

Methemoglobin level

A blood test measuring the percentage of methemoglobin in the blood.

Signup and view all the flashcards

Shifting the Oxygen Dissociation Curve

Factors like increased CO2, low pH, high temperature, and high 2,3-BPG levels shift the curve to the right, indicating less oxygen affinity. Conversely, a decrease in these factors shifts it to the left, meaning a higher oxygen affinity.

Signup and view all the flashcards

Henry's Law

Describes the relationship between the partial pressure of a gas and its solubility in a liquid. In blood, it explains how a tiny amount of oxygen dissolves in plasma.

Signup and view all the flashcards

Hemoglobin's Role

Hemoglobin is a protein in red blood cells that carries oxygen throughout the body, enabling efficient delivery to cells and supporting essential metabolic processes.

Signup and view all the flashcards

Globin Chains

Large protein components of hemoglobin, coming in different types like alpha, beta, gamma, and delta chains.

Signup and view all the flashcards

Types of Hemoglobin

There are three main types of hemoglobin: Hemoglobin A (adult), Hemoglobin A2 (also adult), and Hemoglobin F (fetal). Each has a slightly different composition of globin chains.

Signup and view all the flashcards

What conditions cause a rightward shift?

Increased CO2 levels, low pH (acidity), high temperature, and high 2,3-BPG levels cause a rightward shift.

Signup and view all the flashcards

What conditions cause a leftward shift?

Lower CO2 levels, higher pH (alkalinity), lower temperature, and low 2,3-BPG levels cause a leftward shift.

Signup and view all the flashcards

How does a right shift affect oxygen delivery?

A rightward shift promotes oxygen release to tissues, ensuring more oxygen for metabolism.

Signup and view all the flashcards

How does a left shift affect oxygen delivery?

A leftward shift reduces oxygen release to tissues, conserving oxygen for future needs.

Signup and view all the flashcards

What is the role of 2,3-BPG?

2,3-bisphosphoglycerate (2,3-BPG) is a molecule produced by red blood cells that decreases the affinity of hemoglobin for oxygen, promoting oxygen release into tissues.

Signup and view all the flashcards

Why does the curve shift in certain conditions?

The oxygen-hemoglobin dissociation curve shifts due to changes in environmental conditions within red blood cells that influence the binding of oxygen to hemoglobin.

Signup and view all the flashcards

What is the physiological significance of the curve's shifts?

Shifts in the oxygen-hemoglobin dissociation curve ensure that tissues get the right amount of oxygen they need under various conditions.

Signup and view all the flashcards

Right Shift

A change in the oxygen-hemoglobin dissociation curve where hemoglobin releases more oxygen to tissues.

Signup and view all the flashcards

Causes of Right Shift

Factors that increase metabolic activity, like higher CO2 levels, lower pH (acidity), and higher temperature, all cause a right shift.

Signup and view all the flashcards

P50

The partial pressure of oxygen at which hemoglobin is 50% saturated. A higher P50 indicates a rightward shift.

Signup and view all the flashcards

Left Shift

A change in the oxygen-hemoglobin dissociation curve where hemoglobin holds onto oxygen more tightly.

Signup and view all the flashcards

Causes of Left Shift

Factors that decrease metabolic activity, like lower CO2 levels, higher pH (alkalinity), and lower temperature, all cause a left shift.

Signup and view all the flashcards

What is Carbon Monoxide Poisoning?

Carbon monoxide (CO) binds to hemoglobin's iron with 240 times the affinity of oxygen, preventing oxygen binding and leading to functional anemia. This is because CO forms carboxyhemoglobin, which blocks oxygen binding sites, leading to a decrease in the body's oxygen carrying capacity.

Signup and view all the flashcards

What is Carboxyhemoglobin?

Carboxyhemoglobin is a form of hemoglobin where carbon monoxide is bound to its heme group. This prevents oxygen from binding to hemoglobin, leading to a decrease in oxygen carrying capacity.

Signup and view all the flashcards

What is Methemoglobinemia?

Methemoglobinemia is a condition where a significant amount of hemoglobin exists in the Fe3+ state, unable to bind oxygen due to iron oxidation.

Signup and view all the flashcards

What causes Methemoglobinemia?

Certain drugs like benzocaine, nitric oxide, and dapsone can oxidize iron in hemoglobin to the Fe3+ state, leading to methemoglobinemia.

Signup and view all the flashcards

Why is Methemoglobinemia problematic?

Methemoglobinemia causes hypoxia because the Fe3+ state of iron in hemoglobin cannot bind oxygen, leading to a decrease in oxygen carrying capacity.

Signup and view all the flashcards

Treatment for Methemoglobinemia

Methylene blue is the treatment for methemoglobinemia. It is a reducing agent that converts iron from the Fe3+ state back to the normal Fe2+ state, allowing hemoglobin to bind oxygen.

Signup and view all the flashcards

What are the symptoms of Carbon Monoxide Poisoning?

Common symptoms of carbon monoxide poisoning include headache, malaise, nausea, dizziness, and in rare cases, cherry-red lips.

Signup and view all the flashcards

Pulse Oximeter Limitation in CO poisoning

A pulse oximeter cannot differentiate between carboxyhemoglobin and oxyhemoglobin, giving misleadingly high oxygen saturation readings in carbon monoxide poisoning.

Signup and view all the flashcards

How is Carbon Monoxide Poisoning diagnosed?

The diagnosis of carbon monoxide poisoning is made by measuring carboxyhemoglobin levels in the blood. A normal level is less than 3%, smokers may have slightly elevated levels (10-15%), and levels greater than 15% indicate carbon monoxide poisoning.

Signup and view all the flashcards

What is the treatment for Carbon Monoxide Poisoning?

The treatment for carbon monoxide poisoning is oxygen therapy. By supplying high levels of oxygen, the CO molecules are displaced from hemoglobin, restoring oxygen carrying capacity.

Signup and view all the flashcards

What is the characteristic sign of Methemoglobinemia?

Chocolate brown blood is a classic sign of methemoglobinemia, caused by the brown color of methemoglobin.

Signup and view all the flashcards

What is the diagnostic test for Methemoglobinemia?

Methemoglobin levels are measured in the laboratory to diagnose methemoglobinemia.

Signup and view all the flashcards

2,3-BPG in Hypoxia

In chronic hypoxia, red blood cells produce more 2,3-BPG to increase oxygen delivery to tissues.

Signup and view all the flashcards

Myoglobin vs. Hemoglobin

Hemoglobin is more efficient for oxygen delivery to tissues because it releases oxygen more readily than myoglobin at lower oxygen partial pressures.

Signup and view all the flashcards

Study Notes

Hemoglobin: Oxygen Transport and Regulation

  • Oxygen is transported in blood; a small amount dissolves in plasma (determined by Henry's law: partial pressure of O2 x solubility = dissolved O2), but hemoglobin carries 98% of it, crucial for cellular energy.

Hemoglobin Structure and Types

  • Hemoglobin is composed of globin chains (alpha, beta, gamma, delta) and heme.
  • Globin chains are globular proteins; four chains in two pairs form every hemoglobin molecule.
  • Heme is a non-peptide molecule with iron at the center, bound to porphyrin ring; iron binds oxygen.
  • Three main types in humans:
    • Hemoglobin A (adult): two alpha and two beta chains (most common).
    • Hemoglobin A2 (adult): two alpha and two delta chains (less common).
    • Hemoglobin F (fetal): two alpha and two gamma chains (predominant in fetal development).

Oxygen-Hemoglobin Dissociation Curve

  • Plots oxygen partial pressure (PaO2) vs. hemoglobin saturation.
  • S-shaped (sigmoidal) due to positive cooperativity: one oxygen binding enhances affinity for subsequent oxygen binding on the same hemoglobin molecule.

Positive Cooperativity and Allosteric Effect

  • Binding of the first oxygen molecule increases hemoglobin's affinity for subsequent oxygen molecules.
  • Hemoglobin is an allosteric protein: binding of a molecule at one site affects binding at other sites.
  • This is a positive allosteric effect.

Hemoglobin Dissociation Curve Shifts

  • Rightward shift (favoring oxygen release):
    • Increased PCO2 (carbon dioxide): produced by metabolism.
    • Decreased pH: indicative of higher PCO2.
    • Increased temperature: also associated with higher metabolic rate.
    • Increased 2,3-bisphosphoglycerate (2,3-BPG) levels: common in hypoxia.
  • Right shift increases oxygen delivery to tissues.
  • Leftward shift (favoring oxygen binding): opposite of right-shift conditions. Higher affinity, more oxygen binding.

Fetal Hemoglobin (HbF)

  • HbF has a higher oxygen affinity than adult hemoglobin (HbA), a left-shifted curve,
  • This higher affinity facilitates oxygen uptake from maternal blood. The left shift is due to less 2,3-BPG binding to gamma chains of HbF compared to beta chains of HbA.

Myoglobin

  • Found in skeletal muscles and heart, single-chain protein, binds one oxygen molecule.
  • Myoglobin saturation curve is hyperbolic. This facilitates efficient oxygen storage in muscles.

Pathological Conditions Affecting Hemoglobin

  • Carbon Monoxide Poisoning: CO binds to heme with higher affinity. This causes functional anemia due to decreased oxygen carrying capacity and impaired oxygen unloading. Left-shifted curve, lower unloading, diagnosis by carboxyhemoglobin levels (> 15%). Treatment: Oxygen.
  • Methemoglobinemia: iron in ferric (Fe3+) state, cannot bind oxygen. Results in chocolate-brown blood, hypoxia. Diagnosis by met-hemoglobin levels. Treatment: methylene blue(reduce iron to the ferrous (Fe2+) state).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Description

Test your knowledge about hemoglobin's role in oxygen transport, its structural components, and the oxygen-hemoglobin dissociation curve. This quiz covers essential concepts related to hemoglobin types and their significance in human physiology.

More Like This

Hemoglobin Synthesis and Structure
12 questions
Hemoglobin Structure and Function Quiz
24 questions
Адам қанындағы гемоглобин
10 questions
Physiologie respiratoire - Cours 5
41 questions

Physiologie respiratoire - Cours 5

UnfetteredNovaculite7329 avatar
UnfetteredNovaculite7329
Use Quizgecko on...
Browser
Browser