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31

with a relaxed diaphragm: lungs=
chest wall

lungs= elastic force relaxed
chest wall= elastic force relaxed

32

with inhalation, the diaphragm ______________________________ and the lungs & chest wall __________________.

active muscle contraction
actively expand
* increase in negative pressure, similar to vacuum

33

during inspiration the external intercostals:

elevate and therefore increase the volume of the pleural cavities

34

during inspiration the diaphragm:

depresses the inferior wall of the thoracic cavity and, therefore, increase the volume of the cavities

35

during expiration the internal intercostals:

compress and lower the ribs and therefore decrease the volume of the pleural cavities

36

during expiration the abdominals:

compress the abdominal cavity which elevates the abdominal organs and passively elevates the diaphragm and, therefore, decreases the volume of the pleural cavities.

37

diffusion=

transfer of oxygen from alveolar sacs to pulmonary circulation

38

what 5 principles is diffusion based on:

1. surface area of alveolar capillary membrane
2. diffusing capacity of alveolar-capillary membrane
3. pulmonary capillary blood volume
4. ventilation / blood volume
5. transit time of blood in alveolar capillary membrane

39

what does the amount of oxygen that diffuses across alveolar-capillary membrane vary with?

varies directly with size (surface area) and inversely with thickness.

40

decrease the surface area and increase in thickness -->

decrease in amount of O2 in blood

41

vent (v) / perf (Q) =

0.8

42

apical low perfusion =

lung base perfusion increased due to gravity

43

apical alveoli expand fully =

lung base enlarged vessels compress alveoli

44

what does optimal function of the heart depend on?

synchronized coupling of electrical conduction and mechanical contraction

45

cardiac output =

-preload
-force (inotropic effect) & rate of contraction (chronological effect)
-afterload

46

what are two measures of myocardial impairment?

heart rate
ejection fraction

47

large vessels =

elastic & connective tissue

48

medium to small vessels =

more smooth muscle

49

what do arteriolar regulate blood flow through?

regional vascular beds
(hydrostatic = out , oncotic = in)

50

O2 diffusion (__________ content to ____________ content) occurs quickly

high to
low

51

intravenous at PO2 averages ____mm Hg

23mmHg

52

Only _____mmHg pressure needed for cell metabolism

3mmHg

53

OER: amount of O2 extracted at _______ = 23%

rest

54

rate of O2 extraction regulated by oxygen ___________ (not oxygen availability)

demand

55

partially desaturated blood and CO2 are removed from:

cells to venous circulation

56

what are factors that "shake up" O2 transport

normal: activity, position, emotional stress
disease: bed rest, fever, disease itself, inflammation process, medication, fluid imbalance

57

what is the greatest influence on O2 transport?

Gravity

58

humans are designed to function:

upright (1G)

59

60% of body weight is fluid so...:

small shifts in Gravity --> big fluid shifts

60

restricted activity:

-impacts CO and VO2 with exercise (decrease)
-impacts OER (decrease
-multiple other systems are affected