Ch. 23 Respiratory System pt. 2

What four factors (excluding the pressure of oxygen) affect the affinity of hemoglobin for oxygen?

1. acidity (pH) 2. partial pressure of carbon dioxide 3. temperature 4. BPG

In what two ways does the bohr effect work? (remember, the bohr effect occurs when hemoglobin changes and is less saturated with oxygen)

1. an increase in hydrogen in blood causes oxygen to unload from hemoglobin 2. the binding of oxygen to hemoglobin causes unloading of hydrogen from hemoglobin

The rate of pulmonary and systemic gas exchange depends on what 4 factors?

1. partial pressure differences 2. surface area available for gas exchange 3. diffusion distance 4. molecular weight and solubility of the gases

98.5% of oxygen in the blood is bound to hemoglobin and trapped inside RBCs, therefore only the ___% that is dissolved is capable of diffusing out of tissue capillaries and into tissue cells

1.5

Only ___% of oxygen in the blood is available for diffusion

1.5

Oxygen does not dissolve easily in water, so only about ____% of inhaled oxygen is dissolved in blood plasma

1.5

Oxygen diffuses out of the capillaries, where its partial pressure is ____ mmhg, into the tissue cells where its partial pressure is ____ mmhg

100 mmhg in oxygenated blood, to systemic tissue cells with partial pressures of 40 mmhg for oxygen

In oxygenated blood, the partial pressure of oxygen is _____ mmhg, and the partial pressure of carbon dioxide is ______ mmhg

100mmhg for oxygen, 40 mmhg for carbon dioxide

Oxygen diffuses from alveolar air, where its partial pressure is ____ mmhg, into the blood in pulmonary capillaries, where its partial pressure is only ______ mmhg

105 mmhg in alveolar air, to 40 mmhg in pulmonary capillaries

In a person at rest, tissue cells, on average, need only _____% of the available oxygen in oxygenated blood

25

At rest, only ____% of oxygen in the blood is diffusing out to tissues

25 (so 75% of oxygen remains in the blood and acts as a reserve)

Each hemoglobin is capable of binding to ____ oxygen molecules

4

The heme portion of hemoglobin contains ______ atoms of iron, each capable of binding to a molecule of oxygen

4

In deoxygenated blood, the partial pressure of oxygen is _____ mmhg, and the partial pressure of carbon dioxide is ____ mmhg

40 mmhg for oxygen, 45 mmhg for carbon dioxide

In systemic tissue cells, the partial pressure of oxygen is _____ mmhg, and the partial pressure of carbon dioxide is ____ mmhg

40 mmhg for oxygen, 45 mmhg for carbon dioxide

Carbon dioxide diffuses from deoxygenated blood, where its partial pressure is ____ mmhg, into the alveoli air where its partial pressure is _____ mmhg

45 mmhg in deoxygenated blood, to 40 mmhg in the alveoli

Despite its name, deoxygenated blood retains _____% of its oxygen content

75

About ___% of the oxygen in blood does not dissolve in blood plasma and is instead bound to hemoglobin in red blood cells

98.5

As carbon dioxide enters the blood, much of it converts to carbonic acid. The carbonic acid then dissociates into hydrogen ions and bicarbonate ions. What does this result in?

As hydrogen concentration increases pH lowers. Therefore, the partial pressure of carbon dioxide creates a more acidic environment, helping to release oxygen from hemoglobin

________ is a substance found in red blood cells that decreases the affinity of hemoglobin for oxygen, and thus helps unload oxygen from hemoglobin

BPG (2, 3-bisphosphoglycerate)

colder temperatures increases __________ of hemoglobin for oxygen

affinity

When hemoglobin loses its affinity for oxygen, this is called the ______

bohr effect

Does oxygen or carbon dioxide diffuse more rapidly and why?

carbon dioxide diffuses 20 time more rapidly than oxygen. Even though oxygen has a lower molecular weight than carbon dioxide, oxygen has a lower solubility than carbon dioxide

As acidity increases (pH decreases), the affinity of hemoglobin for oxygen ______

decreases, and oxygen dissociates more readily from hemoglobin

the separation of oxygen and hemoglobin is termed ______

dissociation

________ is gas exchange in the lungs

external respiration

_________ in the lungs converts deoxygenated blood to oxygenated blood

external respiration

__________ is the diffusion of oxygen from air in the alveoli of the lungs to blood in pulmonary capillaries and the diffusion of carbon dioxide from pulmonary capillaries to alveoli of the lungs

external respiration

External respiration only occurs in the ________, while internal respiration occurs in ________

external respiration - only in the lungs internal respiration - in tissues throughout the body

T or F : elevated pH decreases affinity of hemoglobin for oxygen

false; elevated pH levels increases the affinity of hemoglobin for oxygen

T or F: As acidity increases (pH decreases), oxygen has a harder time dissociating from hemoglobin

false; oxygen dissociates more readily from hemoglobin with increased acidity/decreased pH

T or F: There are very few capillaries around the alveoli

false; there is a very large number of capillaries near alveoli in the lungs, and blood flows slowly enough through these capillaries that it picks up a maximal amount of oxygen (blood is fully saturated with oxygen)

Carbon dioxide diffuses from tissue cells, where its partial pressure is _____ mmhg, to systemic capillary blood where its partial pressure is _____ mmhg

from tissue cells with partial pressure of 45 mmhg, to systemic blood capillaries with partial pressure of 40 mmhg

the exchange of oxygen and carbon dioxide between systemic capillaries and tissue cells is called __________

internal respiration

The rate of oxygen diffusion into the blood is faster when the difference between oxygen pressure in alveolar air and pulmonary capillary blood is ______; diffusion is slower when the difference is ______

larger, smaller

The partial pressure of carbon dioxide and pH are related because low blood pH results from high......

low blood pH results from high partial pressures of carbon dioxide

As temperature increases, so does the amount of ______ released from hemoglobin

oxygen

As the partial pressure of carbon dioxide rises, hemoglobin releases _____ more readily

oxygen

Increased acidity enhances the unloading of ________ from hemoglobin

oxygen

At the systemic tissue cell level, ______ is diffusing into blood, and _______ is diffusing from blood into the tissues

oxygen diffusing from blood to tissue cells, carbon dioxide diffusing from tissue cells to blood

At alveoli, ______ is diffusing into the blood, and _______ is diffusing out of the blood

oxygen diffusing into the blood from air of alveoli, carbon dioxide diffusing out of blood to alveoli air

The higher the ______, the more oxygen that combines with hemoglobin

partial pressure of oxygen

The most important factor that determines how much oxygen binds to hemoglobin is the _______

partial pressure of oxygen

BPG is formed in _________

red blood cells

Each hemoglobin has a heme with four atoms of iron, each capable of binding to an oxygen molecule. Each time an oxygen binds to an iron, the next oxygen binds easier (this happens each time), this is a process called _____

subunit cooperativity

T or F : Hemoglobin binding to oxygen is an easily reversible process which can be used to dump oxygen in tissues in order to meet demands

true

T or F: At rest, 75% of oxygen remains in the blood, acting as an oxygen reserve

true

T or F: Blood leaving the lungs is 100% saturated with oxygen

true

T or F: Each gas diffuses independently of one another from an area where its partial pressure is higher to an area where its partial pressure is lower

true

T or F: lowered pH drives oxygen off of hemoglobin, making more oxygen available for tissue cells

true

T or F: the greater the level of BPG, the more oxygen that is unloaded from hemoglobin

true