Exam 5: Chapter 18

Question 1

what is hypoxia?

Answer 1

low blood O2

Question 2

what is hypercapnia?

Answer 2

high blood CO2

Question 3

what is the equation representing CO2 conversion into bicarbonate ion?

Answer 3

CO2 + H2O = H+ + HCO3-

Question 4

which has a higher pressure of O2, alveoli or pulmonary capillaries?

Answer 4

alveoli
(alveoli –> pul. cap.)

Question 5

which has a higher pressure of CO2, alveoli or pulmonary capillaries?

Answer 5

pulmonary capillaries
(alveoli <– pul. cap.)

Question 6

which has a higher pressure of O2, the cells or systemic capillaries?

Answer 6

systemic capillaries
(systemic capillaries –> cells)

Question 7

which has a higher pressure of CO2, the cells or systemic capillaries?

Answer 7

cells
(systemic capillaries <– cells)

Question 8

how does a higher altitude effect pressure gradients in the lungs?

Answer 8

atmospheric pressure is lower than normal
-pressure gradient in the lungs is less strong
-decreases diffusion

Question 9

what is hypoventilation?

Answer 9

lower volumes of air entering the alveoli

Question 10

what are three ways that hypoventilation can occur?

Answer 10

-decreased lung compliance
-increased resistance
-CNS depression (alcohol poisoning, drug overdose)

Question 11

what happens to diffusion when the concentration gradient increases?

Answer 11

diffusion increases

Question 12

what happens to diffusion when surface area increases?

Answer 12

diffusion increases
-emphysema (destroys alveoli)

Question 13

what happens to diffusion when permeability increases?

Answer 13

diffusion increases
-fibrotic lung disease

Question 14

what happens to diffusion when distance increases?

Answer 14

diffusion decreases
-pulmonary edema (fluid in lungs)

Question 15

what happens to diffusion when resistance increases?

Answer 15

diffusion decreases
-asthma

Question 16

which has better O2 solubility, the alveoli or capillaries?

Answer 16

alveoli

Question 17

which is more soluble, CO2 or O2?

Answer 17

CO2

Question 18

which has a higher partial pressure, RBC or cells?

Answer 18

cells

Question 19

what in the RBC binds O2?

Answer 19

hemoglobin
-iron+O2 = oxyhemoglobin (HbO2)
-COOPERATIVE (changes shape so it can bind to other O2)

Question 20

what happens to the Hb-O2 binding affinity when O2 increases?

Answer 20

increases Hb-O2 binding affinity
-Law of Mass Action: drive the unbinding too!

Question 21

what happens to Hb-O2 binding affinity when plasma O2 partial pressure increases?

Answer 21

increases Hb-O2 binding affinity

Question 22

what does the plasma O2 partial pressure determine?

Answer 22

the % saturation of Hb

Question 23

what happens to O2 when Hb levels decrease?

Answer 23

decrease in O2 transported

Question 24

what happens when the oxyhemoglobin curve shifts right?

Answer 24

decrease in Hb-O2 binding affinity

Question 25

what happens to Hb-O2 binding affinity when temperature increases?

Answer 25

decreases Hb-O2 binding affinity

Question 26

what happens to Hb-O2 binding affinity when CO2 levels increase?

Answer 26

decreases Hb-O2 binding affinity

Question 27

what happens to Hb-O2 binding affinity when pH levels increase (basic)?

Answer 27

increases Hb-O2 binding affinity -due to lesser amounts of CO2

Question 28

what happens to Hb-O2 binding affinity when 2,3-BPG levels increase?

Answer 28

decreases Hb-O2 binding affinity

Question 29

what is the process of O2 entering the body once it is in the alveoli?

Answer 29

1. alveoli 2. dissolved in plasma 3. enters RBC and binds to Hb 4. leaves RBC and dissolves in plasma 5. enters cell

Question 30

what are the three ways CO2 is transported?

Answer 30

1. dissolved in plasma 2. bound to Hb (carbaminohemoglobin) 3. converted to bicarbonate (MAJORITY)

Question 31

what is the process of CO2 getting converted to a bicarbonate in the RBC?

Answer 31

1. converted using carbonic anhydrase in the RBC 2. HCO3- exits RBC and goes into the plasma, Cl- goes into the RBC (antiporter) 3. HCO3- goes back into the RBC and the rxn reverses back into CO2 4. CO2 goes into the alveoli 5. partial pressures push CO2 out of the body

Question 32

what respiratory muscles are skeletal muscles?

Answer 32

internal and external intercostals -can move voluntarily

Question 33

what muscles does the medulla control?

Answer 33

both inspiratory and expiratory muscles -contains the DRG, PRG, and VRG

Question 34

what is the nucleus tractus solitarius (NTS)?

Answer 34

contains the dorsal respiratory group (DRG)

Question 35

what is the dorsal respiratory group (DRG)?

Answer 35

controls muscles of inspiration

Question 36

how does the DRG send its output?

Answer 36

through phrenic nerve (controls diaphragm) and intercostal nerves (controls intercostal muscles)

Question 37

what is the pontine respiratory groups (PRG)?

Answer 37

help decides how quickly DRG neurons fire -smooth rhythm -located in the pons (depth of ventilation)

Question 38

what is the ventral respiratory group (VRG)?

Answer 38

contains the pre-botzinger complex and other areas

Question 39

what does the pre-botzinger complex do?

Answer 39

has pacemaker cells that control rhythm of respiration -controls firing fate of PRG

Question 40

what do the other areas in the VRG do?

Answer 40

controls active breathing muscles controls expiration

Question 41

what happens to ventilation with a low O2, high CO2, and low pH?

Answer 41

increase ventilation -get rid of CO2

Question 42

what happens to ventilation with a high O2, low CO2, and high pH?

Answer 42

decrease ventilation -we need more CO2

Question 43

what are peripheral chemoreceptors?

Answer 43

receptors that detect changes in O2, CO2, and pH -located outside the CNS in the carotid and aortic arteries

Question 44

what is the process of the peripheral receptors when O2 is low?

Answer 44

1. low O2 2. close K+ channels 3. depolarization 4. Ca2+ entry 5. NT release 6. brain 7. increases ventilation **we need a large change in O2 to trigger this**

Question 45

what are central chemoreceptors?

Answer 45

receptors that detect changes in CO2 (pH)

Question 46

what is the process of central chemoreceptors when CO2 is high?

Answer 46

1. high CO2 2. peripheral receptors 3. BBB (blood brain barrier) 4. CO2 -> HCO3- 5. increases H+ (decrease pH) 6. central chemoreceptors 7. increase ventilation

Question 47

what are some protective reflexes in the respiratory system?

Answer 47

-physical injury or irritation (constriction, sneezing, coughing) -overinflation (Hering-Breuer Response)

Question 48

what is the Hering-Breuer Response?

Answer 48

1. increase in tidal volume (overinflation) 2. activates mechanoreceptors (stretch) 3. info sent to brain 4. terminate inspiration

Question 49

how does the cerebrum and hypothalamus control the respiratory system?

Answer 49

works through the brainstem -breath rate & depth -we have some voluntary control of this (breathing techniques)

Question 50

how does the limbic system control the respiratory system?

Answer 50

emotions! (fear, excitement) -bypasses brainstem!!!

Question 51

do we always have voluntary control of our respiratory system?

Answer 51

NO! -eventually the medulla's chemoreceptors take over "you can only hold your breath for so long"