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Flashcards in 3.5 Respiratory 1 Deck (55):
1

Volume of pulmonary flow

Same as systemic CO

2

Pressure of pulmonary blood circulation

LOW
25/8mm Hg
MAP ~14 mm Hg

3

Why is the MAP of pulmonary blood circulation so much lower than systemic?

Low resistance due to
-Shorter distance / shorter vessels heart to lungs
-Greater total diameter of pulmonary arterioles / capillaries

4

What is the pleural cavity?

Closed space (airtight) filled with fluid

5

What do visceral and parietal pleura epithelia do?

Make slippery and tacky pleural fluid to lubricate, yet create surface tension to hold the lungs against chest wall as they inflate and deflate

6

What draws air in and out of airway?

Pressure changes in pleural cavity

7

Trachea, bronchi and bronchiole surface is lined with...

Ciliated epithelia and mucus secreting goblet cells

8

What do goblet cells do?

Catch and remove foreign material, convey it up to esophagus

9

Anatomy of airways (in order)

Trachea -> Bronchi-> Bronchioles -> Alveoli

10

Trachea branches about ___ times to terminate as ~____ alveoli

25
300 million

11

Alveoli

Huge surface area (tennis court)
Lung epithelium immediately adjacent to capillaries, no muscle, just elastic tissue

12

Boyle's Gas Law

Increase Volume -> Decrease pressure

13

Inspiration

Volume INCREASE during diaphragm CONTRACTION decreases alveolar pressure-air enters

14

Expiration

Volume decrease during diaphragm relaxation increases alveolar pressure-air exits

15

Do alveoli have elasticity?

Yes! They recoil back to original shape when stretched (expiratory force)

16

Tendency for alveoli to recoil is balanced by..

Low pressure vacuum in the intrapleural cavity

17

Alveolar elastic recoil force is due to..

1) Elastic tissue surrounding alveoli
2) Surface tension of alveolar fluid

18

What is surfactant and what does it do?

A detergent that tries to reduce surface tension

19

Lung collapse is due to...

A) Loss of vacuum in interpleural cavity
B) Surface tension problems

20

Pneumothorax

Lung collapses due to hole or air penetration between body wall and inter pleural cavity (no vacuum created)

21

Infant respiratory distress syndrome

Not enough surfactant in premature infants makes it difficult to expand lungs due to stickiness of fluid within alveoli

22

What is the role of lymphatic vessels in gas exchange in alveoli?

Prevent fluid build-up at exchange surface, due to blood pressure

23

Alveolar type II cell

Make surfactant, lowers surface tension of fluid inside alveoli (like a detergent), prevents wall collapse

24

What is the role of macrophages in alveoli?

Clear debris b/c no cilia in alveoli

25

Gas exchange

How atmospheric gases enter the alveoli, then diffuse into / out of your RBCs

26

3 Factors affecting Gas Exchange

1) Respiratory membrane thickness
2) Surface Area (SA)
3)Partial pressure gradient

27

Respiratory membrane thickness

5 layers, normally very thin
Pulmonary Edema

28

Pulmonary edema

Interstitial fluid layer expands, increases gas exchange distance, reduced efficiency of exchange

29

Interstitial space is..

Space between type 1 alveolar cell and endothelial cell

30

Two things that can lead to pulmonary edema

Congestive heart failure, pneumonia

31

Emphysema

Loss of alveolar walls (decreases surface area)

32

Partial pressure

Concentration of a gas in a liquid will equilibrate with or equal to the partial pressure of the gas in contact with the liquid

33

Partial pressure

Concentration of a gas in a liquid will equilibrate with or equal to the partial pressure of the gas in contact with the liquid

34

Is there usually equilibrium between blood and air?

No, rarely because of gas usage in cell metabolism

35

Where does CO2 in blood come from?

Glucose

36

Is O2 higher in blood or tissues usually?

Blood

37

Is CO2 higher in blood or tissues usually?

Tissues

38

Why is oxygen low and carbon dioxide high in systemic tissues?

Cellular respiration (glucose to carbon dioxide and oxygen to water)

39

Oxygen is carried in the plasma within..

RBCs, bound to hemoglobin

40

Carbon dioxide is carried as the plasma primarily as...

Bicarbonate (HCO3-)

41

What is a small amount of CO2 carried by?

Carried bound to amino acids in hemoglobin protein

42

At rest, _____ of the oxygen bound to hemoglobin is unloaded in the tissues

25%

43

During exercise, up to _____ oxygen bound to hemoglobin is unloaded in active tissues to drop PO2

65%

44

X-axis of oxygen-hemoglobin dissociation curve

Partial pressure of oxygen in tissues

45

Bohr Effect

pH impacts the oxygen-hemoglobin dissociation curve

46

As blood pH decreases, amount of oxygen bound to hemoglobin...

Also decreases

47

What does hemoglobin do under acidic conditions?

Gives up O2 more readily

48

Why does hemoglobin release O2 more readily under acidic conditions?

Increase in H+ ions changes shape of hemoglobin, decreases its affinity for oxygen

49

Where does the curve shift as pH decreases?

To the right

50

Hemoglobin "picks up on both...

Oxygen concentration and pH

51

CO2 +H2O create H2CO3 with the assistance of..

Carbonic anyhydrase
(slow reaction when uncatalyzed)

52

What does H2CO3 turn into spontaneously in water?

HCO3- and H+

53

Carbonic anyhydrase

Very high concentration in RBCs
Catalyzes chemical reaction in BOTH directions
RBCs are CO2 and HCO3- factories

54

In systemic tissue, CO2..

Is converted to HCO3- by RBCs and delivered to plasma

55

In the lungs, HCO3-...

Enters RBC (pumped in, Cl- exchanged)
Converted to CO2 and H2O and diffuses out to air in lungs