Transport & Diffusion of Gases
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Questions and Answers

What is the adaptive advantage of hemoglobin in oxygen absorption?

  • Blood cells contain nuclei to store more hemoglobin.
  • It releases oxygen at the same rate regardless of saturation.
  • It can only hold one molecule of oxygen.
  • Each molecule can hold 4 oxygen molecules, allowing efficient binding. (correct)

The fetus receives its oxygen directly from the air around it.

False (B)

What happens to hemoglobin's shape when an oxygen molecule binds to it?

It changes shape, making it easier for more oxygen molecules to bind.

A fetus is more efficient at extracting oxygen from the mother's blood when her blood is lower in __________.

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

Match the following terms to their definitions:

<p>Oxygen Dissociation Curve = Graph showing how hemoglobin saturation changes with oxygen pressure Hemoglobin = Protein in red blood cells that carries oxygen Placenta = Organ that facilitates nutrient and gas exchange between mother and fetus Fetus = Developing organism in the womb</p> Signup and view all the answers

What percentage of CO2 is carried in the blood as bicarbonate ions?

<p>73% (D)</p> Signup and view all the answers

CO2 is only transported in the blood as dissolved gas.

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

What happens to CO2 and H2O in the blood in terms of carbonic acid formation?

<p>CO2 combines with H2O to form carbonic acid, which dissociates into bicarbonate ions and hydrogen ions.</p> Signup and view all the answers

At high altitudes, the partial pressure of _____ decreases, leading to a reduction in the rate of diffusion.

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

Match the percentage of CO2 transport in blood to its corresponding form:

<p>Dissolved in plasma = 7% Carbaminohemoglobin = 20% Bicarbonate ions = 73%</p> Signup and view all the answers

What is a common symptom of altitude sickness?

<p>Shortness of breath (C)</p> Signup and view all the answers

The oxygen concentration in the air remains constant regardless of altitude elevation.

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

What is the primary gas carried by red blood cells in the human body?

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

Calculate the partial pressure of oxygen at 500 mmHg atmospheric pressure.

<p>105 mmHg</p> Signup and view all the answers

The density of atmospheric air increases as altitude increases.

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

What percentage of oxygen is typically found in atmospheric air?

<p>21%</p> Signup and view all the answers

Each hemoglobin molecule can carry ___ O2 molecules.

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

Match the following gases with their descriptions:

<p>Oxygen = Most abundant gas in the atmosphere Carbon Dioxide = Gas produced by cells during respiration Carbon Monoxide = Dangerous gas that prefers hemoglobin over oxygen Nitrogen = Makes up the largest percentage of atmospheric air</p> Signup and view all the answers

At sea level, what is the atmospheric pressure measured in kPa?

<p>101.3 kPa (B)</p> Signup and view all the answers

Carbon monoxide is colorless and odorless, making it unnoticeable.

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

What happens to oxygen when blood encounters oxygen-depleted tissue?

<p>Oxygen diffuses from the blood into the cells.</p> Signup and view all the answers

Flashcards

Atmospheric Pressure

The force exerted by air on a surface. It is measured in pascals (Pa) or kilopascals (kPa) and decreases with increasing altitude.

Diffusion

The transport of gases from an area of high concentration to an area of low concentration.

Hemoglobin

The protein in red blood cells that binds to oxygen. Each hemoglobin molecule can carry four oxygen molecules.

Oxygen Transport

The process by which oxygen is transported in the blood. 98.5% of oxygen is carried by hemoglobin in red blood cells, and the remaining 1.5% dissolves in plasma.

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Carbon Dioxide Transport

The process by which carbon dioxide is transported in the blood. Carbon dioxide diffuses from cells into the blood.

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Carbon Monoxide (CO)

A dangerous air contaminant that binds to hemoglobin, preventing it from transporting oxygen.

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Partial Pressure of Oxygen (Po2)

The pressure of oxygen in the blood.

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Partial Pressure of Carbon Dioxide (Pco2)

The pressure of carbon dioxide in the blood.

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Oxygen Dissociation Curve

A graph that shows the relationship between the partial pressure of oxygen (pO2) and the percentage of hemoglobin saturation with oxygen.

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Fetal Hemoglobin

Hemoglobin in fetal red blood cells has a higher affinity for oxygen than adult hemoglobin. This means it can pick up more oxygen from the mother's blood even at lower oxygen levels.

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Cooperative Binding

The ability of hemoglobin to bind oxygen more readily once one oxygen molecule has already attached. It makes oxygen uptake more efficient.

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Adaptive Advantage of Fetal Hemoglobin

Fetal hemoglobin's higher affinity for oxygen allows it to efficiently extract oxygen from the mother's blood, even when it is relatively low in oxygen.

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Role of the Placenta

The placenta is the organ connecting the fetus to the mother's circulatory system. This allows for the exchange of nutrients, oxygen, and waste products.

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What is PCO2?

The partial pressure of carbon dioxide in the blood is a measure of the amount of CO2 dissolved in the blood.

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How is CO2 transported in the blood?

Carbon dioxide is transported in the blood in three ways: dissolved in plasma, bound to hemoglobin, and as bicarbonate ions.

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What is the most common way CO2 is carried in the blood?

Bicarbonate ions (HCO3-) are the main form of CO2 transport. They are formed in red blood cells when CO2 reacts with water.

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Why is bicarbonate formation important?

The conversion of CO2 to bicarbonate ions creates hydrogen ions (H+) in the blood. These ions can make the blood more acidic.

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What happens to the H+ ions produced during bicarbonate formation?

The body uses buffers to maintain a stable pH balance. Buffers absorb excess H+ ions to prevent blood from becoming too acidic.

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How does altitude affect oxygen transport?

At higher altitudes, the partial pressure of oxygen (PO2) is lower. This makes it harder for oxygen to diffuse into the blood.

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What is altitude sickness?

Altitude sickness can occur because of reduced oxygen absorption. Symptoms include shortness of breath, headache, dizziness, and fatigue.

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What is the oxygen dissociation curve?

The oxygen dissociation curve shows the relationship between the partial pressure of oxygen and the percentage of hemoglobin saturation.

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Study Notes

Transport & Diffusion of Gases

  • Gases transport and diffuse to support life functions.
  • Diffusion is the net movement of molecules from an area of high concentration to an area of low concentration.

The Atmosphere

  • Earth is surrounded by an atmosphere, most dense near sea level and less dense at higher altitudes.
  • Atmospheric pressure is measured in pascals (Pa) or kilopascals (kPa).
  • At sea level, pressure is 101.3 kPa or 760 mmHg; and at Mount Everest it's 31 kPa or 250 mmHg.

Composition of Atmosphere

  • Inhaled and Exhaled air composition in a typical subject
    • Inhaled air: nitrogen (78%), oxygen (21%), carbon dioxide (0.04%), water vapor (0.96%), and other gases (<1%).
    • Exhaled air: nitrogen (78%), oxygen (15%), carbon dioxide (4%), water vapor (3%), and other gases (<1%).

Gas Exchange

  • Oxygen and carbon dioxide diffuse across the gas exchange surface of the lungs.
  • The efficiency of this process depends on the maximization of surface area and the difference in gas concentrations.

Concentration of Gases

  • Oxygen diffusion from alveoli to blood increases when the oxygen concentration gradient increases.
  • A large gradient between alveoli and blood leads to faster oxygen movement.
  • Partial pressure (P) is used to measure the driving force of gas movement.
    • The partial pressure of oxygen (P02) increases diffusion rate.

Transport of Gases in the Blood (Oxygen)

  • The partial pressure of oxygen (P02) in inhaled air (13.3 kPa) is higher than in incoming blood (5.33 kPa).
  • Oxygen diffuses into the bloodstream
  • In body tissues (oxygen-depleted tissues), the oxygen partial pressure in the cells is only 5.33kPa. -Blood's oxygen diffuses to cells.

Transport of Gases in Blood (Oxygen) - How Oxygen is Carried

  • Blood contains red blood cells (RBCs) and plasma
  • Most oxygen (98.5%) is carried by RBCs as oxyhemoglobin
  • Hemoglobin (Hb) in RBCs contains four heme groups.
  • Each heme group carries one oxygen molecule
  • Each RBC contains ~270 million Hb molecules

Transport of Gases in Blood (Oxygen): Release

  • When blood encounters oxygen-depleted tissue, the PO2 in the blood is higher than in cells.
  • Oxygen dissociates from the iron atoms in haemoglobin.
  • The lower pH (acidity) near cells also causes oxygen release.
  • Oxygen diffuses out of the blood into the tissue cells via interstitial fluid to enter mitochondria.

Transport of Gases in Blood (Carbon Monoxide (CO))

  • CO is a dangerous air pollutant because hemoglobin prefers CO over oxygen
  • Prevents oxygen from reaching body tissues
  • Is odourless and colourless; being inhaled unnoticed.
  • Lethal concentrations cause unconsciousness and death.

Transport of Gases in Blood (Carbon Dioxide (CO2))

  • PCO2 in interstitial tissue (5.60 kPa) is higher than in blood.

Transport of Gases in Blood (Carbon Dioxide (CO2)) - How it is Carried

  • Some CO2 is dissolved in plasma

  • 20% is carried by hemoglobin as carbaminohemoglobin.

  • 73% is carried as bicarbonate ions in the blood plasma (a reaction involving carbonic acid).

  • A reaction occurring during transport releases H+ that must be removed from blood for homeostasis. HCO3- and H+ form Carbonic Acid.

Effect of Altitude on Respiration

  • The concentration of oxygen does not change at high altitudes.
  • However, density and pressure are lower.
  • The lower pressure gradient makes oxygen diffusion slower.

Effects of Altitude Sickness

  • Shortness of breath
  • Headache
  • Dizziness
  • Nausea
  • Tiredness

Oxygen Dissociation Curve (Graph interpretation)

  • Illustrates how effectively blood carries oxygen.
  • Shows the relationship between partial pressure and percent oxygen saturation.

Oxygen Dissociation Curve (Sample Questions)

  • At a given altitude (e.g., halfway up Mount Everest), oxygen partial pressure. -Determine oxygen saturation % from the dissociation curve

How Low is Too Low?

  • Blood oxygen level guidance for health concerns/problems and when to seek medical attention.

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Transport & Diffusion of Gases SBI3U(G) PDF

Description

This quiz explores the transport and diffusion of gases essential for life functions. It covers the composition of the atmosphere, measurements of atmospheric pressure, and the gas exchange process in lungs. Test your understanding of how gases behave and support vital processes.

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