chapter 23-2: respiratory system

Question 1

air flow is _______ related to pressure gradient and _________ related to resistance

Answer 1

directly; indirectly

Question 2

how does pressure gradient influence air flow?

Answer 2

deeper breath = increased throacic volume = decreased intrapulmonary pressure = increased pressure gradient (and vice versa)

Question 3

what 2 factors influence resistance?

Answer 3

bronchiole diameter and compliance (ease of expansion); both are inverselt related to resistance

Question 4

forced expiratory volume is the percent of ___________ that can be expelled in one second. This value is obtained by inspiring as much air as possible and expelling air ______________

Answer 4

vital capacity; as quickly as possible

Question 5

___________________ is the volume of air left in the conducting zone after inspiration

Answer 5

anatomical dead space

Question 6

what is the formula for minute ventilation?

Answer 6

respiration rate x tidal volume

Question 7

what is the formula for alveolar ventilation?

Answer 7

respiration rate (tidal volume - anatomical dead space)

Question 8

what 3 factors are the efficiency of pulmonary gas exchange dependent on?

Answer 8

1. partial pressure and gas solubilites (steep O2 gradient - Po2 = 104 (air) - 40 (blood) mmHg; high CO2 solubility)
2. thickness and surface area of respiratory membrane (0.5 micrometers, large surface area)
3. ventilation-perfusion coupling

Question 9

PO2 controls _______ by changing ________ diameter; PCO2 controls ______ by changing ________ diameter

Answer 9

perfusion; arteriole; ventilation; bronchiole

Question 10

if ventilation is ______ than perfusion, bronchioles will ______ in response to _________ CO2; if ventilation is ______ than perfusion, bronchioles will _______ in response to _________ CO2

Answer 10

less; dilate; increased; greater; constrict; decreased

Question 11

what is the relationship between O2 sats and PO2?

Answer 11

they have a direct relationship

Question 12

PO2 after ____________ is 104 mmHg (98%) and 40 mmHg (75%) after ______________. this means only 20-25% is released

Answer 12

leaving the lungs; tissue gas exchange

Question 13

how can you change rate and depth?

Answer 13

you can change rate by altering amount of time in inspiration and expiration; you can change depth by stimulating accessory muscles

Question 14

the most important stimulus for chemoreceptors is _________

Answer 14

blood Pco2

Question 15

What do central chemoreceptors do?

Answer 15

they monitor pH of CSF and changes in H+ induced by blood Pco2

Question 16

__________ chemoreceptors respond to H+ from other sources other than PCO2 conversion

Answer 16

peripheral

Question 17

where are peripheral chemoreceptors found?

Answer 17

aortic arch and bifurcation of common carotid arteries (in carotid bodies)

Question 18

how are proprioceptors, baroreceptors, and irritant receptors stimulated?

Answer 18

proprioceptors - stimulated by movement
baroreceptors - stimulated when overstretched
irritant receptors - stimulated by particulates

Question 19

how are the cough and sneeze reflexes initiated?

Answer 19

cough - irritants in the trachea and bronchi
sneeze - irritants in the nasal cavity

Question 20

how do the 3 structures of the higher brain centers influence breathing rate?

Answer 20

hypothalamus - increases breathing rate if body is warm, decreases if cold
limbic system - alters breathing rate in response to emotions/memories
cerebral cortex - controls voluntary changes in breathing patterns (singing, breath holding, talking)

Question 21

how does blood Pco2 change during hyperventilation?

Answer 21

hyperventilation ↑Po2 and ↓Pco2 in the alveoli = ↓Pco2 in blood

Question 22

what is hypocapnia?

Answer 22

low blood CO2

Question 23

___________ is breathing that is too slow (_________) or too shallow (____________)

Answer 23

hypoventilation; bradypnea; hypopnea

Question 24

what is hypercapnia?

Answer 24

high blood CO2

Question 25

low blood Po2 (__________) can lead to low O2 in tissues (_________)

Answer 25

hypoxemia; hypoxia

Question 26

what are the 8 steps of movement of O2 and CO2?

Answer 26

1. inspiration
2. O2 diffuses into blood
3. O2 is transported in the blood
4. O2 diffuses into cells
5. CO2 diffuses into blood
6. CO2 is transported in the blood
7. CO2 diffuses into alveoli
8. expiration