Ch 18

Question 1

areas of the brain that regulate breathing

Answer 1

medulla and pons

Question 2

oxygen and Co move into and out of the blood at

Answer 2

pulmonary and systemic capillaries

Question 3

oxygen exchange occurs at

Answer 3

alveolar-capillary interface

Question 4

oxygen is transported via

Answer 4

hemoglobin

Question 5

oxygen is exchanged with cells for

Answer 5

carbon dioxide

Question 6

CO2 is exchanged from

Answer 6

capillaries to alveoli

Question 7

fisk’s law of diffusion states

Answer 7

diffusion rate = (SA x conc gradient x permeability) / membrane thickness

Question 8

which factor is most important to diffusion rate

Answer 8

concentration gradient

Question 9

moving from a gas to a liquid is directly proportional to which factors

Answer 9

pressure gradient
solubility
temperature

Question 10

is O2 or CO2 more soluble

Answer 10

CO2 is much more soluble`

Question 11

partial pressures of O2 in circulation

Answer 11

alveoli - 100 mm Hg
oxygenated tissue - 100 mm Hg
peripheral tissue - <40 mm Hg
de-oxygenated tissue - 40 mm Hg

Question 12

partial pressures of CO2 in circulation

Answer 12

alveoli - 40 mm Hg
oxygenated tissue - 40 mm Hg
peripheral tissue - >46 mm Hg
oxygenated tissue - 46 mm Hg

Question 13

types of hypoxia

Answer 13

hypoxic - low O2
anemic - low O2 bound to Hb
Ischemic - reduced blood flow
Histotoxic - failure to use O2 bc poison

Question 14

hypercapnia

Answer 14

too much Co2
cause system to panic

Question 15

emphysema effect on alveolar ventilation

Answer 15

destruction of alveoli means less SA for gas exchange

Question 16

Gibrotic lung dieseas effect on alveolar ventilation

Answer 16

thickening of alveolar membrane slows gas exchange
loss of lung compliance may decrease alveolar ventilation

Question 17

pulmonary edema

Answer 17

fluid in interstitial space increases diffusion distance
CO2 levels may not be altered

Question 18

asthma

Answer 18

increased airway resistance decreases alveolar ventilation

Question 19

oxygen diffuses across ______ to enter the plasma

Answer 19

alveolar epithelial cells and capillary endothelial cells

Question 20

gas transport in the blood begins with

Answer 20

O2 leaving alveoli for blood bc of low partial pressure in blood

Question 21

once in the blood, 98% of O2 _____ while the other 2% _____

Answer 21

binds to hemoglobin;
dissolves in plasma

Question 22

hemoglobin and O2 dissolved in plasma both

Answer 22

transport to cells and exit the blood

Question 23

physical factors that alter Hb affinity for O

Answer 23

pH, temperature, P(CO2), 2,3-DGP

Question 24

an increase in pH ____ HbO binding

Answer 24

increases; more basic

Question 25

an increase in temperature ____ HbO binding

Answer 25

decreases

Question 26

an increase in P(CO2) ____ HbO binding

Answer 26

decreases;
CO2 competes for binding sites

Question 27

an increase in 2,3-DPG ____ HbO binding

Answer 27

decreases;
a normal amount is needed so that O will stay bound long enough to be delivered

Question 28

percentages of CO2 in transport

Answer 28

dissolved: 7%
converted to bicarbonate ion: 70%
bound to Hb: 23%

Question 29

before being converted to bicarbonate, CO2 becomes

Answer 29

carbonic acid

Question 30

bicarbonate has the ability to

Answer 30

dissolve in plasma and act as a buffer

Question 31

stimuli for reflex control of ventilation

Answer 31

emotions, CO2, O2`=

Question 32

integrating centers for stimuli

Answer 32

emotions - higher brain centers + limbic
all - MO and pons

Question 33

sensory receptors for stimuli

Answer 33

Co2 - medullary chemoreceptors
CO2 and O2 - carotid and aortic chemoreceptors

Question 34

respiratory neurons in the medulla control _____ while neurons in the pons modulate ______

Answer 34

inspiration and expiration;
ventilation

Question 35

peripheral chemoreceptors properties

Answer 35

-located in carotid and aortic arteries
-specialized glomus cells
-sense changes in PO2, pH and PCo2 central chemoreceptors