Phys: Diffusion And Transport Of Gas

Question 1

How does gas exchange in the lung occur?

Answer 1

By simple diffusion

Question 2

What does diffusion of gas depend on? (3 things)

Answer 2

-pressure gradient of the gas
-surface area
-thickness

Question 3

What is partial pressure?

Answer 3

The pressure exerted by each individual gas in a mixture

Question 4

A gas will dissolve in _______ in proportion to its ______________

Answer 4

Fluid, partial pressure

Question 5

Which partial pressures drive the diffusion across the respiratory membrane?

Answer 5

P_O2 and P_CO2

Question 6

A _______ P_O2 gradient exits across the respiratory membrane. What does this cause?

Answer 6

large, oxygen to diffuses rapidly from alveoli into pulmonary capillary blood

Question 7

P_CO2 gradient diffuses in the opposite direction under a ________ pressure gradient. What does this cause?

Answer 7

Smaller, equal amounts of O₂ and CO₂ are exchanged

Question 8

What is the P_O2 in the alveoli? Pulmonary arteries?

Answer 8

Alveoli - 104mmHg
Pulmonary arteries - 40mmHg

Question 9

What is the P_CO2 in the alveoli? Pulmonary arteries?

Answer 9

Alveoli - 45mmHg
Pulmonary arteries - 40mmHg

Question 10

Which law determines gas transferred/unit time?

Answer 10

Fick’s law

Question 11

What happens when the surface area is decreased?

Answer 11

Decreases in gas exchange

Question 12

What diseases can decrease surface area?

Answer 12

Degenerative lung diseases and pulmonary embolism

Question 13

What happens if the thickness of the membrane increases?

Answer 13

Gas exchange takes longer

Question 14

What does the amount of oxygen delivery depend on?

Answer 14

-function of circulatory and respiratory systems
-blood flow to tissues
-oxygen content of blood
-oxygen consumption by the tissues

Question 15

What happnes to oxygen carrying capacity in anemia?

Answer 15

Oxygen carrying capacity decreases

Question 16

What is oxygen carrying capacity?

Answer 16

The maximum amount of oxygen that can bind to the hemoglobin

Question 17

What is the normal oxygen carrying capacity?

Answer 17

20 mL O2/dL of blood

Question 18

What is oxygen content?

Answer 18

The sum of oxygen bound to hemoglobin and oxygen in free form (dissolved form) in each 100 mL of blood

Question 19

What is hemoglobin saturation?

Answer 19

Percentage of hemoglobin present as oxyhemoglobin

Question 20

What are the two forms that oxygen can be transported in the blood?

Answer 20

-dissolved in plasma (1.5-2%)
-bound to hemoglobin (98-98.5%)

Question 21

What does Henry’s law say?

Answer 21

The amount of gas that dissolves in a liquid is proportional to the partial pressure of the gas in contact with the liquid

Question 22

What is hemoglobin?

Answer 22

The oxygen carrying protein within the red blood cells

Question 23

How many molecules of hemoglobin are in each cell?

Answer 23

250 million molecules

Question 24

Hb [ ] in males

Answer 24

14-18 g/dl

Question 25

Hb [ ] in females

Answer 25

12-16 g/dl

Question 26

What is the Main function of Hb?

Answer 26

Transport of oxygen and carbon dioxide

Question 27

What is Hb composed of?

Answer 27

A heme portion and a globin portion

Question 28

What is located in the heme part of Hb?

Answer 28

4 heme groups that contain iron where O2 can bind

Question 29

What is in the globin portion of Hb?

Answer 29

4 polypeptide chains in two pairs

Question 30

What are the 2 polypeptide chains in HbA?

Answer 30

2 alpha and 2 beta chains

Question 31

What are the two polypeptide chains in HbA2?

Answer 31

2 alpha and two delta chains (Maybe not delta idfk Greek letters)

Question 32

What are the two polypeptide chains in HbF?

Answer 32

2 alpha and 2 gamma chains

Question 33

Which Hb has a greater affinity for O2?

Answer 33

HbF

Question 34

How many oxygen molecules can each Hb molecule bind?

Answer 34

4

Question 35

What happens to the affinity of Hb to O2 as it binds more O2?

Answer 35

Affinity increases with each molecule of O2 that binds

Question 36

What happens if iron on Hb is in the oxidized state?

Answer 36

It is unable to bind O2 and is called methemoglobin

Question 37

What is oxygen saturation?

Answer 37

The percentage of Hb that is present as oxyhemoglobin

Question 38

When Hb is fully saturated, how many mL of O2 can each gram of Hb bind?

Answer 38

1.34 mL

Question 39

What is the shape of the oxygen-hemoglobin dissociation curve normally?

Answer 39

Sigmoid shaped

Question 40

What happens if the curve shifts towards the right side?

Answer 40

There is a decrease in affinity and oxygen is released

Question 41

What happens when the curve is shifted towards the left?

Answer 41

There is increases affinity of Hb for oxygen and more loading of oxygen

Question 42

What factors cause a right shift and O2 offloading?

Answer 42

-increased temp -increased hydrogen -increased CO2 -high 2,3 DPG

Question 43

What factors cause a left shift and more loading of oxygen?

Answer 43

-decreased temperature -decreased hydrogen -decreased CO2 -low 2,3 DPG

Question 44

What happens to the curve when you reduce pH?

Answer 44

The curve shifts to the right, decreased affinity and more offloading

Question 45

What happens to the curve when you increase 2,3 DPG?

Answer 45

The curve shifts tot the right and increases O2 offloading

Question 46

What type of binding occurs in hemoglobin-oxygen bond?

Answer 46

Cooperative binding

Question 47

What happens in carbon monoxide poisoning?

Answer 47

CO binds Hb 200x stronger than O2, so CO poisoning significantly reduces the ability of Hb to carry O2

Question 48

Which direction does CO poisoning shift the curve?

Answer 48

Towards the left because it stabilizes the relaxed state of Hb

Question 49

Which direction does HbF shift the curve?

Answer 49

Towards the left, since there is higher affinity for O2 in HbF than HbA

Question 50

What causes the poor binding of 2,3 BPG in HbF?

Answer 50

2,3-BPG cannot bind to the gamma chains in fetal hemoglobin

Question 51

What does the high affinity of HbF cause?

Answer 51

Hypoxia, which leads to increased rbc formation

Question 52

Why is it important for HbF to have a higher affinity for oxygen?

Answer 52

So the fetus can get enough oxygen from the mother during pregnancy

Question 53

What happens to Hb and O2 content in polycythemia?

Answer 53

Hb increases and O2 increases

Question 54

What happens to Hb and O2 content in anemia?

Answer 54

Hb decreases and O2 content decreases

Question 55

What happens to Hb and O2 content in CO poisoning?

Answer 55

Hb normal, and O2 content decreases

Question 56

___% of CO2 is transported as dissolved CO2

Answer 56

10%

Question 57

____% of CO2 is transported as carbamino compounds (bound to protein)

Answer 57

20%

Question 58

___% of CO2 is transported as bicarbonate

Answer 58

70% - main form of transport

Question 59

**know transport of CO2 in blood

Question 60

What two factors control respiration?

Answer 60

-neural factors (involuntary and voluntary control) -chemical factors

Question 61

What nerves come from the LMN in the cervical segments?

Answer 61

Phrenic nerve that innervates diaphragm

Question 62

What nerves come from the LMN in the thoracic segment?

Answer 62

Intercostal nerves that innervate intercostal muscles

Question 63

What is the respiratory center?

Answer 63

A functionally integrated collection of neurons that are located at different levels of the CNS and participate in control of respiration

Question 64

What is the basic rhythm of respiration generator from the medullary respiratory rhythmicity center?

Answer 64

Dorsal respiratory group

Question 65

What is the other group from the medullary rhythmicity center?

Answer 65

Ventral respiratory group

Question 66

What inhibits inspiration and regulates volume and rate of respiration?

Answer 66

Pneumotaxic center

Question 67

What happens if damage to pneumotaxic center?

Answer 67

Irregular respiration patterns

Question 68

Where is pneumotaxic center located?

Answer 68

Upper pons

Question 69

What do chemoreceptors do?

Answer 69

Detective changes in partial pressure of carbon dioxide, partial pressure of oxygen, and pH in the blood or CSF and send feedback to respiratory centers to modulate the breathing pattern to maintain proper levels

Question 70

Where are peripheral chemoreceptors located?

Answer 70

Carotid and aortic bodies

Question 71

What are peripheral chemoreceptors stimulated by?

Answer 71

Low P_O2 (hypoxia)

Question 72

Where are the central chemoreceptors located?

Answer 72

The medulla

Question 73

What stimulates the central chemoreceptors?

Answer 73

-high P_CO2 (hypercapnia) -high [H+]

Question 74

What is the ventilators response to decreased P_O2? What does it result in?

Answer 74

Hyperventilation, results in decreases P_CO2 and increased P_O2