3.6.2. O2 and CO2 Transport Flashcards Preview

CPR Week 6 > 3.6.2. O2 and CO2 Transport > Flashcards

Flashcards in 3.6.2. O2 and CO2 Transport Deck (56)
Loading flashcards...
1

There are 3 parts to the respiratory system what are they?

Conduction zone Respiratory zone Pump

2

What is the conduction zone

Nasal cavity, Nasopharynx, Larynx, Trachea and bronchi

3

What is the respiratory zone

Bronchioles and alveoli

4

What is the pump

Chest wall skeleton/muscles, diaphragm, elastic connective tissue

5

Major vs. minor functions of respiratory system

Major Function: facilitates the exchange of gases in and out of tissue (provides oxygen and removes carbon dioxide) Minor Functions: vocalization, removal of irritants (coughing/sneezing), and temperature control

6

Describe the Oxygen transport life cycle and what each phase is called

From atmospheric air to lung alveoli (pulmonary ventilation) From lung alveoli through layers of the respiratory membrane to hemoglobin (simple diffusion) From pulmonary capillaries to tissue capillaries (blood circulation) From hemoglobin to interstitial fluid and tissue cells (simple diffusion)

7

Describe the CO2 transport life cycle and what each phase is called

From tissue cells to interstitial fluid and blood (simple diffusion) From tissue capillaries to pulmonary capillaries (blood circulation) From blood across respiratory membrane layers to lung alveoli (simple diffusion) From lung alveoli out to atmospheric air (expiration)

8

Pressure vs. partial pressure

Pressure is the force of molecules against a surface, and thus pressure is directly proportional to the concentration of gas molecules Partial pressure = Total pressure x Fractional Gas Concentration

9

Why does O2 come into the lungs and CO2 leave?

There is a partial pressure for CO2 in the atmosphere of 0.3 and in the lungs is 40. Following pressure gradients, the CO2 will want to break into the atmosphere (H2O follows this same pathway with similar pressure changes) For 2, it has atmospheric pressure of 159 and a lung pressure of 104, making it go into the lungs

10

What is Henry's Law?

Henry’s Law: the amount of a given gas dissolved in a liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid

11

Henry;s law is complex, but what is it basically saying?

More soluble = higher concentration of gas Less soluble = lower concentration of gas

12

Partial pressure =

concentration/solubility

13

Carbon dioxide is ___ times ____ (more/less) soluble than oxygen

Carbon dioxide is >20 times more soluble than oxygen

14

If CO2 is more than 20X soluble than oxygen, what does that mean the state of gasses will be for a given partial pressure?

AKA at a given partial pressure, the concentration of carbon dioxide molecules is 20 times greater than oxygen molecules

15

Solubility coefficients for common gasses

Oxygen = 0.024; Carbon dioxide = 0.57; Carbon monoxide = 0.018; Nitrogen = 0.012; Helium = 0.008

16

The greater the solubility of a gas, _______________________.

The greater the solubility of a gas, the greater number of molecules available to diffuse

17

Factors that affect diffusion rate proportionally:

Solubility of the gas in fluid; Difference in partial pressure between compartments; Cross-sectional (surface) area for diffusion; Temperature

18

Factors that affect diffusion rate inversely:

Square root of the molecular weight of the gas; Distance of diffusion

19

Diffusion of oxygen between alveolar air and blood in pulmonary capillaries is ____

Diffusion of oxygen between alveolar air and blood in pulmonary capillaries is rapid

20

Diffusion of oxygen between alveolar air and blood in pulmonary capillaries is rapid Why?

1. Cross-sectional (surface) area for diffusion 2. Distance of diffusion Anatomic structures are optimized for these two factors Pulmonary capillary blood volume = 65-100 mL Alveolar surface area = 70-100 square meters

21

True or False: One of the important factors in transport is diffusion

Driven by cardiac force; blood is pumped to peripheral tissues; diffusion is not significant in transport

22

_____ of oxygen transported in blood is dissolved in either plasma or the RBC cytoplasm (low solubility compared to carbon dioxide)

Only 3% of oxygen transported in blood is dissolved in either plasma or the RBC cytoplasm (low solubility compared to carbon dioxide)

23

_____ of oxygen is transported in RBCs bound to hemoglobin _____% of all proteins in a RBC are hemoglobin _______ molecules of hemoglobin in each RBC

Remaining 97% is transported in RBCs bound to hemoglobin 95% of all proteins in a RBC are hemoglobin 280 million molecules of hemoglobin in each RBC

24

How many and what types of chains are found in hemoglobin?

2 alpha and 2 beta

25

Discuss allosteric binding as it pertains to hemoglobin

Binding causes a conformational change to allow for easier binding of the next oxygen molecule to a different unoccupied heme group in hemoglobin

26

Factors that alter oxygen-hemoglobin dissociation curve

Hydrogen ions Carbon dioxide Temperature 2,3-bisphosphoglycerate

27

Hydrogen ions Carbon dioxide Temperature 2,3-bisphosphoglycerate These factors alter the oxygen-hemoglobin dissociation curve. What do they do?

An increase in any of these factors results in a decrease of hemoglobin affinity for oxygen: CURVE SHIFTS TO THE RIGHT All of these factors increase during exercise

28

Discuss the Bohr effect

Peripheral tissues are using oxygen and producing CO2. Increased CO2 leads ot increased hydrogen ions (Bohr Effect)

29

Formula for how CO2 changes 

30

pH in the tissues vs in the lungs

Tissues pH = 7.2

Lungs pH = 7.6

31

Discuss how a hemoglobin saturation curve changes due to pH

32

Diffusion to Peripheral Tissues is driven by what

Driven by partial pressures between arterial capillary and interstitial fluid

33

Minimal PO2 requirement for biochemical processes in cells ranges from ____ to ____

Minimal PO2 requirement for biochemical processes in cells ranges from 1-3 mmHg

34

During physiological conditions where oxygen demand is significantly increased, the respiratory system can still supply enough oxygen so that intracellular PO2 is not below ____.

During physiological conditions where oxygen demand is significantly increased, the respiratory system can still supply enough oxygen so that intracellular PO2 is not below 5 mmHg

35

Discuss the issue with oxygen supply we see at higher altitudes and why that occurs

Altitude = less barometric pressure

Oxygen at 5000 feet (120 mmHg); On Mt Everest (36 mmHg)

36

How and why does CO cause poisoning?

CO binds to hemoglobin with 200x more affinity than O2

Rely on Plasma O2 transport (remember 3% of oxygen is carried this way)

37

Discuss oxygen changes with anemia

Anemia = change in oxygen carrying capacity

May be compensated by cardiac output

38

Why is fire dangerous in regards to oxygen?

Fires = oxygen consumed

39

___ ____ is responsible for oxygen transport to peripheral tissues. ___________________ govern transport

Simple diffusion is responsible for oxygen transport to peripheral tissues. Differences in oxygen partial pressures govern transport

40

Discuss the mechanisms and where they locate for CO2 transport in the blood.


40

41

_____ mL of carbon dioxide is transported from tissues to the lungs per 100 mL of blood

4 mL of carbon dioxide is transported from tissues to the lungs per 100 mL of blood

42

In what forms is CO2 transported and in what degrees?

Dissolved CO2 (7%)

Carbamino compounds (23%)

As bicarbonate atoms (70%)

43

Carbon dioxide reacts with water to form carbonic acid which dissociates into bicarbonate and hydrogen ions

Where does this occur and at what speed and why?

Occurs SLOWLY in PLASMA, but RAPIDLY in RBC because of the enzyme carbonic anhydrase (~5,000 times faster)

44

How does Bicarbonate leave the cell? What does this cause?

Bicarbonate leaves the cell via a bicarbonate-chloride exchanger protein (aids in further dissociation of carbonic acid)

Facilitated diffusion (i.e., no energy is utilized)

Chloride maintains electroneutrality

Chloride shift = RBCs in venous blood have higher intracellular chloride ion concentrations than in arterial blood

45

Carbon dioxide may also react with proteins instead of water (no enzymatic activity is present)

Where does this occur and why?

RBCs

Protein concentration is greater in RBCs

Hb forms carbamino compounds more easily

Hb is a buffer for the H+ that is produced

46

What is the Haldane Effect?

Oxygen binding to hemoglobin causes carbon dioxide to be released from the blood more effectively

47

Oxygen binding to Hg makes it become a ____ ____; released hydrogen ions bind with _____ and form carbonic acid which dissociates into ____ and _____.

Oxygen binding to Hg makes it become a stronger acid; released hydrogen ions bind with bicarbonate and form carbonic acid which dissociates into CO2 and water

48

Oxygen binding to ______________ displaces the _____ from it directly  

Oxygen binding to carbaminohemoglobin displaces the CO2 from it directly  

49

Effects of CO2 on blood pH

Carbonic acid (formed first) has an effect on blood pH

Changed from 7.41 in arterial blood to 7.37 in venous blood

50

When do we see respiratory acidosis?

Decreased alveolar ventilation (drug overdose)

Lung-diffusing capacity (pulmonary edema)

Decreased diffusion (acute respiratory distress)

51

Increased arterial PCO2 → what?

 

How does the body respond?

Increased arterial PCO2 → Increased H+ and HCO3- → lower pH

Arterial PCO2 > 44 mmHg

Blood pH < 7.35

Renal system compensatory mechanism will increase HCO3- to return blood pH to normal levels (Increase HCO3- leads to the reverse reaction, causing more CO2 and thus less H+)

52

When do we get respiratory alkalosis?

Response to hypoxia, anxiety, drug toxicity, and fever

53

54

Decreased arterial PCO2 →  what?

How does the body respond?

Decreased arterial PCO2 → Decreased H+ and HCO3- → higher pH

Arterial PCO2 < 35 mmHg

Blood pH > 7.45

Renal system compensatory mechanism will decrease HCO3- to return blood pH to normal levels

55

Hemoglobin disassociation curves for being at rest vs. exercise