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From Flashcardlet > BMS 108 Ch. 16 Respiratory System > Flashcards

BMS 108 Ch. 16 Respiratory System Flashcards

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0
Q

What is ventilation?

A

Moves air in and out of lungs for gas exchange (external respiration)

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1
Q

What three related functions does respiration encompass?

A
  1. ventilation
  2. gas exchange
  3. O2 utilization
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2
Q

What is gas exchange?

A

Exchange of gas between air and blood and blood and tissues.

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3
Q

What is O2 utilization?

A

cellular respiration

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4
Q

Is gas exchange active or passive?

A

passive; gas always exchanged down its concentration gradient

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5
Q

How many alveoli in the lungs?

A

300 million

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6
Q

What is an alveolar type 1 cell? type 2?

A

alveolar wall; cell that secretes surfactant in the alveoli

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7
Q

What law governs ventilation?

A

Boyle’s Law (P=1/V)

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8
Q

What is compliance?

A
  • how easy the lungs expand with pressure

- reduced by factors that cause resistance to distention (e.g. pulmonary fibrosis)

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9
Q

What is elasticity?

A
  • the tendency to return to initial size after distention

- elastic tension increases during inspiration and is reduced by recoil during expiration

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10
Q

What is surface tension?

A
  • cohesive forces between liquid molecules that allows them to resist an external force
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11
Q

What causes surface tension in water molecules?

A

Hydrogen bonds

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12
Q

What are the forces that promote alveolar collapse and resist distention?

A

surface tension and elasticity

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13
Q

Surface tension acts to ________ the alveoli; thus __________ pressure of air within alveoli.

A

collapse; increases

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14
Q

Why don’t alveoli normally collapse?

A

surfactant

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15
Q

What is surfactant secreted by? What is it’s function?

A

Type II alveolar cells; lowers surface tension by getting between H20 molecules, preventing surface tension from collapsing alveoli

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16
Q

What connects the lungs to the thoracic cavity?

A

the pleura

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17
Q

What is intrapulmonary pressure?

A
  • pressure inside alveoli (inside lungs)
  • must become < atmospheric P for air to enter lungs
  • when intrapulmonary P is > than atmospheric P, expiration occurs
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18
Q

What is intrapleural pressure?

A
  • pressure in the intrapleural space (outside the lungs)

- due to thoracic cavity pulling out and the lungs trying to collapse in (elasticity & surface tension)

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19
Q

What is partial pressure of gases?

A

The pressure that a particular gas in a mixture exerts independently.

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20
Q

What is Dalton’s Law?

A

States that total pressure of a gas mixture is the sum of partial pressure of each gas in a mixture.

21
Q

What is atmospheric pressure at sea level?

A

760 mm Hg

22
Q

What is gas exchange in the lungs driven by?

A

Difference in partial pressures of gases between alveoli and capillaries.

23
Q

What three things facillitate diffusion of gases in the alveoli?

A
  1. enormous surface area of alveoli
  2. short diffusion distance between alveolar air and capillaries
  3. tremendous density of capillaries
24
Q

What are the normal arterial partial pressures of O2 and CO2? veins?

A

100mmHg, 40mmHg; 40mmHg, 46mmHg

25
Q

What is breathing regulated by?

A
  • autonomic breathing is generated by a rhythmicity center in the medulla oblongata
26
Q

How does the medulla know what rate and depth to breathe at?

A

Using chemoreceptors in the aortic arch, carotid sinus and medulla

27
Q

What are these chemoreceptors triggered by?

A

a rise in H+

28
Q

What is hypocapnia?

A

low CO2, caused by hyperventilation

29
Q

What is hypercapnia?

A

high CO2; caused by hypoventilation

30
Q

What is respiratory acidosis?

A

a rise in carbonic acid in the blood caused by hypoventilation

31
Q

What is respiratory alkalosis?

A

hyperventilation that results in low blood CO2

32
Q

Which chemoreceptors have the greatest effect on ventilation?

A

medulla

33
Q

Can H+ cross the BBB? CO2?

A

No; yes

34
Q

What is the arterial pCO2 level the body tries to maintain?

A

40mmHg

35
Q

How sensitive are chemoreceptors to H+? pCO2? pO2?

A

Most sensitive; less sensitive; barely notice

36
Q

What is hypoxemia? what effect does it have on ventilation?

A

low blood pO2; little

37
Q

Is the bulk of O2 in the blood dissolved O2 or bound to hemoglobin?

A

bound to hemoglobin

38
Q

How many O2 molecules can each hemoglobin carry? How many hemoglobins in 1 RBC? how many RBCs in the body?

A

4; 300 mil; 300 mil

39
Q

What is hemoglobin bound with O2 called? unbound?

A

oxyhemoglobin; deoxyhemoglobin

40
Q

High pO2 in lungs (alveoi) favors _________; low pO2 in tissues favor __________.

A

loading; unloading

41
Q

Arterial hemoglobin is ___% saturated with O2.

A

97

42
Q

What causes changes in Hb-O2 affinity?

A

pH and temperature

43
Q

Affinity ____ when pH decreases (Bohr effect) or temperature increases.

A

decreases

44
Q

Decrease affinty = _________ unloading.

A

better

45
Q

How is CO2 transported in the blood?

A
  1. dissolved CO2 (10%)
  2. carbaminohemoglobin - bound to hemoglobin (20%)
  3. bicarbonate ion - HCO3- (70%)
46
Q

How is H2CO3 catalyzed into CO2 and H2O?

A

With carbonic anhydrase (enzyme)

47
Q

What is the chloride shift?

A
  1. High CO2 levels in blood cause bicarbonate buffer equation to shift right
  2. Results in high H+ and HCO3- in RBC
  3. HCO3- in RBC diffuss down concentration and charge gradient into blood plasma
  4. Counteracted by Cl- moving into the RBC
48
Q

Where does the chloride shift occur?

A

in tissues

49
Q

What is the reverse chloride shift?

A
  1. In lungs, bicarbonate buffer equation shifts left as CO2 is exhaled
  2. Binding of O2 to hemoglobin decreases its affinity for H+
  3. H+ combines with HCO3- and more CO2 is formed
  4. Cl- diffuses down concentration gradient out of RBC
50
Q

What is the normal pH of the blood?

A

7.4

51
Q

What is the kidney’s role in acid-base blood balance?

A

excrete H+

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