Bio 219: Blood Gas Transport

Front 1

Blood is the body's only _____ tissue.

Back 1

fluid

Front 2

Blood includes liquid plasma and formed elements such as

Back 2

• Erythrocytes
• Leukocytes
• Platelets
• Plasma

Front 3

Hemocrit

Back 3

% of RBCs out of total blood volume (normally ~45%)

Front 4

What are erythrocytes?

Back 4

red blood cells (RBCs)

Front 5

What are leukocytes?

Back 5

white blood cells (WBCs)

Front 6

What are platelets?

Back 6

membrane bound cell fragments (w/ enzymes); involved in blood clotting

Front 7

What is plasma?

Back 7

non-living fluid matrix (H₂O + electrocytes), proteins, glucose, etc

Front 8

What are the blood plasma components?

Back 8

1) water ~ 92% of plasma
2) > 100 dissolved solutes:
a) plasma proteins
b) non-protein solutes

Front 9

What are plasma proteins?

Back 9

(~7% plasma), most produced in the liver
1) Albumin - most abundant (60% of plasma proteins)
2) Globulins - (35% plasma proteins)
3) Clotting proteins (4% plasma proteins)
4) Enzymes and Hormones (< 1% of plasma)

Front 10

What are non-protein solutes?

Back 10

(~ 1% of plasma)
1) Nutrients/waste products
2) Electrolytes (ions)
3) Gases (O₂/CO₂)

Front 11

All formed elements are from stem cells in _____

Back 11

bone marrow

Front 12

Only _____ are "complete" cells

Back 12

WBCs

Front 13

What formed element has no nuclei, few organelles; platelets are just cell fragments?

Back 13

RBCs

Front 14

Most formed elements survive in the bloodstream for a few/many days.

Back 14

few

Front 15

Most blood cells do not divide are renewed by cells in _____.

Back 15

bone marrow

Front 16

Describe the structure of an erythrocyte.

Back 16

• Biconcave discs
• Increased surface area for gas exchange (~30% more than a round cell)
• enables RBCs to bend & flex - squeeze through capillaries
• Anucleate - not a "true cell" and few organelles
• filled with hemoglobin (Hb) - protein that functions in gas transport

Front 17

What is hemoglobin?

Back 17

transports oxygen and carbon dioxide; makes RBCs red

Front 18

Describe the structure of RBCs

Back 18

Structure - complex, quaternary structure
• Globin (protein) + Heme (pigment complex)
• Globin = 2 alpha chains and 2 beta chains of polypeptides
• Each chain has 1 heme molecule with iron at the center
• 1 heme unit "holds" iron in a way that iron can interact with 1 oxygen molecule

Front 19

Oxygen loading of hemoglobin occurs in the _____.

Back 19

lungs

Front 20

O₂ diffuses from ______ to blood, then through RBC to bind with hemoglobin

Back 20

lung air sacs

Front 21

When O₂ binds to iron, Hb becomes _____.

Back 21

oxyhemoglobin changes to new 3-d shape → becomes ruby red

Front 22

When O₂ detaches to iron, Hb becomes _____.

Back 22

deoxyhemoglobin color changes to dark red

Front 23

Hb transports ______ of oxygen in the blood (bound to iron of heme group)

Back 23

~ 98.5%

Front 24

Hb transports _____ of carbon dioxide in the blood (bound to globin)

Back 24

~ 20%

Front 25

What is carbaminohemoglobin?

Back 25

when CO₂ bind to glob in's amino acids

Front 26

Carbon dioxide loading occurs at the _____.

Back 26

tissues

Front 27

What is hematopoiesis?

Back 27

blood cell formation in the red bone marrow

Front 28

What is hemocytoblasts?

Back 28

blood stem cells
• produce all formed elements (RBCs, WBCs, and platelets)

Front 29

Regulation & Requirements for Erythropoiesis

Back 29

Circulating Erythrocytes - number remains constant and reflects balance between RBC production/destruction
• too few RBCs leads to tissue hypoxia
• too many RBCs causes high blood viscosity

Front 30

Erythropoiesis is _____ controlled

Back 30

hormonally

Front 31

Erythropoietin (EPO) released by the kidneys is triggered by:

Back 31

• Tissue hypoxia (due to decreased RBCs)
• Decreased O₂ availability
• Increased tissue demand for O₂

Front 32

↑ erythropoiesis increases the:

Back 32

• RBC count in circulating blood
• O₂ carrying ability of the blood

Front 33

Erythropoietin Mechanism

Back 33

Homeostasis: Normal blood oxygen levels
Stimulus: Hypoxia due to decreased RBC count, decreased amount of hemoglobin, or decreased availability of O₂

Front 34

What are two erythrocyte disorders?

Back 34

anemia and polycythemia

Front 35

What is anemia?

Back 35

blood has normally low oxygen-carrying capacity

**It is a symptom rather than a disease itself

• Blood oxygen levels cannot support normal metabolism
• Signs/Symptoms include fatigue, paleness, shortness of breath, and chills

Front 36

What is polycythemia?

Back 36

excess RBCs that increase blood viscosity

Three main polycythemias are:
1) polycythemia vera (up to 80% hematocrit), bone marrow cancer
2) secondary polycythemia (decrease oxygen availability/excess EPO)
3) blood doping

Front 37

Blood plasma can't transport enough O₂ or CO₂ to meet physiological needs

Back 37

• O₂ & CO₂ have limited solubilities in blood plasma
• Tissues need more O₂ & generate more CO₂ than can be absorbed or transported

Front 38

Blood plasma can't transport enough O₂ or CO₂ to meet physiological needs and the problem is solved by:

Back 38

Red Blood Cells (RBC)
• Transport O₂ to, and CO₂ from peripheral tissues
• Remove O₂ and CO₂ from plasma, allowing more gases to diffuse into blood

Front 39

O₂ Transport

Molecular O₂ is carried in the _____:

Back 39

blood
• bound to hemoglobin (in RBC)
• dissolved in plasma

Front 40

O₂ Transport

O₂ binds to iron in hemoglobin (Hb) molecules:

Back 40

in a rapid & reversible reaction

Front 41

O₂ Transport

Each RBC has about _____ million Hb molecules:

Back 41

280 million

• each binds 4 oxygen molecules

Front 42

O₂ Transport

• Hb-O₂ combination is

Back 42

oxyhemoglobin (HbO₂)

Front 43

O₂ Transport

• Hb that has released O₂ is

Back 43

deoxyhemoglobin (HHb)

Front 44

O₂ Transport

Each RBC has about _____ million Hb molecules:

Back 44

280 million

• each binds 4 oxygen molecules

Front 45

What is hemoglobin saturation?

Back 45

percentage of heme units (collectively) in a hemoglobin molecule with bound O₂

Front 46

O₂ Transport

• Hb-O₂ combination is

Back 46

oxyhemoglobin (HbO₂)

Front 47

All 4 heme units bound with O₂ is _____ saturation

Back 47

100%

Front 48

O₂ Transport

• Hb that has released O₂ is

Back 48

deoxyhemoglobin (HHb)

Front 49

Each Hb (on average) carries 2 O₂ molecules is _____ saturation

Back 49

50%

Front 50

What is hemoglobin saturation?

Back 50

percentage of heme units (collectively) in a hemoglobin molecule with bound O₂

Front 51

What are the environmental factors affecting the rate of Hb binding/releasing of O₂?

Back 51

1) PO₂ of blood
2) Blood pH
3) Temperature
4) Metabolic activity within RBCs

Front 52

All 4 heme units bound with O₂ is _____ saturation

Back 52

100%

Front 53

How does hemoglobin and PO₂ affect the rate of Hb binding?

Back 53

• Hb is almost completely saturated at a PO₂ of 70 mm Hg
• further increase in PO₂ = small increases in O₂ binding

Front 54

Each Hb (on average) carries 2 O₂ molecules is _____ saturation

Back 54

50%

Front 55

What is oxygen-hemoglobin saturation curve?

Back 55

a graph relating the saturation of hemoglobin to PO₂

• rightward shift means more O₂ will be unloading from Hb at a given PO₂
• in active tissues, ↑ temperature, ↓ pH and ↑ PCO₂ promote unloading of O₂

Front 56

What are the environmental factors affecting the rate of Hb binding/releasing of O₂?

Back 56

1) PO₂ of blood
2) Blood pH
3) Temperature
4) Metabolic activity within RBCs

Front 57

Hemoglobin and PO₂ is a curve rather than a straight line because

Back 57

• Hb changes its shape each time O₂ molecule binds
• allows Hb to bind O₂ when O₂ levels are low

Front 58

How does hemoglobin and PO₂ affect the rate of Hb binding?

Back 58

• Hb is almost completely saturated at a PO₂ of 70 mm Hg
• further increase in PO₂ = small increases in O₂ binding

Front 59

What is oxygen-hemoglobin saturation curve?

Back 59

a graph relating the saturation of hemoglobin to PO₂

• rightward shift means more O₂ will be unloading from Hb at a given PO₂
• in active tissues, ↑ temperature, ↓ pH and ↑ PCO₂ promote unloading of O₂

Front 60

Hemoglobin and PO₂ is a curve rather than a straight line because

Back 60

• Hb changes its shape each time O₂ molecule binds
• allows Hb to bind O₂ when O₂ levels are low

Front 61

Hemoglobin and PO₂

Carbon monoxide (CO) from burning fuels:

Back 61

• binds strongly to hemoglobin and takes place of O₂
• can result in carbon monoxide poisoning

Front 62

How does hemoglobin and pH affect the oxygen-hemoglobin saturation curve?

Back 62

standarized for normal blood (pH 7.4, 37°C)
• When pH drops → more O₂ is released (curve shifts to right & downward)
∙ causes a decrease in oxygen's binding affinity
• When pH rises → less O₂ is released (curve shifts to the left & upward)

Front 63

How does hemoglobin and temperature affect the oxygen-hemoglobin saturation curve?

Back 63

standarized for normal blood (pH 7.4, 37°C)
• When temperature rises → more O₂ is released (curve shifts to the right & down)
• When temperature drops → less O₂ is released (curve shifts to the left & up)

Front 64

Hemoglobin and temperature
When pH drops or temperature rises:

Back 64

more oxygen is released (curve shifts to the right)

Front 65

Hemoglobin and temperature
When pH rises or temperature drops:

Back 65

less oxygen is released (curve shifts to the left)

Front 66

Hemoglobin and pH

active tissues generate ____ which lowers the pH of _____

Back 66

acids; interstitial fluid

Front 67

Hemoglobin and pH

A decrease in pH changes the shape of _____

Back 67

Hb

Front 68

Hemoglobin and pH

Shape change = release of ____ by Hb

Back 68

O₂ which causes the Hb saturation to decline

Front 69

Hemoglobin and temperature

An increase in temperature causes Hb to release more _____

Back 69

O₂

Front 70

Hemoglobin and

A decrease in temperature causes Hb to bind to _____ more tightly

Back 70

O₂

Front 71

How does hemoglobin and BPG (RBC metabolic activity's effect on Hb) affect the binding and release of O₂?

Back 71

RBC (lack mitochondria) generate ATP by glycolysis which forms lactic acid and BPG (2,3-biphosphoglycerate)

BPG directly affects O₂ binding and release

↑ BPG → ↑ O₂ release

Front 72

What are the key concepts of hemoglobin in RBC in O₂ Transport?

Back 72

• carries most blood oxygen
• Hb releases bound O₂ in response to low O₂ partial pressure in surrounding plasma

Front 73

If PO₂ increases, hemoglobin _____ oxygen

Back 73

binds

Front 74

If PO₂ decreases, hemoglobin _____ oxygen

Back 74

releases

Front 75

At a given PO₂: hemoglobin will release additional oxygen if:

Back 75

• pH decreases or
• temperature increases or
• BPG increases

Front 76

What is the Bohr effect?

Back 76

effect of pH on hemoglobin saturation curve (caused by CO₂)

1. CO₂ rapidly diffuses into RBCs once in the blood
2. in RBC, carbonic anhydrase (enzyme) catalyzes a reaction with H₂O to produce carbonic acid (H₂CO₃)
3. Carbonic acid (H₂CO₃) dissociates into hydrogen ion (H+) and bicarbonate ion (HCO₃-)
4. Increase in H+ = decrease in pH

Front 77

↑ CO₂ causes the reaction to proceed to the _____

Back 77

RIGHT

Front 78

↓ CO₂ causes the reaction to proceed to the _____

Back 78

LEFT

Front 79

According to the Bohr effect, how does an increase in CO₂ affect the binding affinity of O₂?

Back 79

add answer here

Front 80

CO₂ is generated as a byproduct of _____.

Back 80

aerobic metabolism (cellular respiration)

Front 81

CO₂ in the bloodstream may be:

Back 81

1. converted to carbonic acid
2. bound to protein portion of hemoglobin
3. dissolved in plasma

Front 82

CO₂ in the bloodstream

___% transported as bicarbonate (HCO₃-)
• carbonic acid (H₂CO₃) quickly dissociates into H+ * HCO₃-
___% bound to Hb molecule forming carbaminohemoglobin
___% transported as CO₂ dissolved in plasma

Back 82

70%, 23%, and 7%

Front 83

Bicarbonate ions move into plasma by an exchange mechanism called the ______ that takes in Cl- ions without using ATP

Back 83

chloride shift

counterbalances negative bicarbonate ions from RBCs

Front 84

CO₂ travels in the bloodstream primarily as bicarbonate ions, which form through dissociation of carbonic acid produced by ______ in RBCs

Back 84

carbonic anhydrase

Front 85

Lesser amounts of CO₂ are bound to _____ or dissolve in the _____

Back 85

Hb; plasma