respiration

Question 1

2 ways for lungs to expand or contract

Answer 1

1. up and down movement of diaphragm lengthens and shortens chest cavity
2. elevation and depression of lungs => changes in ant/post diameter of chest cavity

Question 2

expiration (4)

Answer 2

1. passive (except during emphysema, asthma, exercise)
2. diaphragm relaxes upward and pushes air out of lungs
3. elastic recoil chest wall and abdominal structures compress lungs
4. heavy breathing recruits abdominal muscles

Question 3

inspiration

Answer 3

1. active process

2. diaphragm is contracting downward and sucks air into lungs

Question 4

pleural pressure definition

Answer 4

pressure of fluid in the narrow space btwn lung and chest wall pleura

Question 5

alveolar pressure definition

Answer 5

air pressure inside the alveoli

Question 6

lung compliance def

Answer 6

change in lung volume for each unit change in transpulmonary pressure (difference in pressure btwn alveolar and pulmonary pressure)

Question 7

surface tension in alveoli (3)

Answer 7

1. surfactant (excreted by type II alveolar epithelial cells)= soap that reduces surface tension of water in alveoli
2. surfactant does the “work” of breathing by making lungs more complaint
3. smaller alveolis are more likely to collapse on themseves

Question 8

pulmonary volumes

1. TV
2. IRV
3. ERV
4. RV

Answer 8

1. tidal volume (TV) = 500mL
   air inspired or expired with each normal breath (at rest)
2. inspiratory reserve volume (IRV) = 3,000mL
   breathing in more air after inspiration (extra vol above tidal vol)
3. expiratory reserve volume (ERV)= 1100mL
   breathing out more after expiration this is active expiration
4. residual volume (RV)= 1200mL
   air remaining in lungs even after forceful expiration

Question 9

pulmonary capacities

1. IC
2. FRC*** (vol, def, +2 more things)
3. VC
4. total lung capacity

Answer 9

1. Inspiratory capacity = 3500 mL
   tidal vol (500)+ inspiratory reserve vol (3000) (amt of air we can breathe in from beginning of normal expiration -> distending lungs max)
2. *Functional residual capacity = 2300 mL
   expiratory reserve vol (1100) + residual vol (1200)
   
   • this will always be in lungs and helps keep PP of O2 constant, even during exercise
     - normal respiration allows slow replacement of this reserve
3. vital capacity = 4600 mL
   inspiratory reserve (3000) + tidal vol (500) + expiratory reserve (1100)
   how much we can expel after filling lungs to max, then expiring to the max (we can control this)
4. total lung capacity = 5800 mL
   vital capacity (4600) + residual vol (1200)
   max amt of air that can be in the lungs

Question 10

minute respiratory volume (# and def)

Answer 10

total amt of new air moved into respiratory passages/ minute

TV(500) * breaths/min (12) = 6000mL/min

Question 11

alveolar ventilation ( 3- # and def)

Answer 11

1. rate at which new air reaches gas exchange area of lungs
2. some air will fill respiratory passageways and never reach gas exchange areas = dead space
3. breaths/ min (12) * (tidal vol- dead space 500-150) 4200 mL/min

Question 12

3 types of dead space

Answer 12

1. anatomical dead space- air in conducting airways that is not involved in gas exchange
2. alveolar dead space- air in gas exchange portions of lungs that cannot engage in gas exchange (generally 0)
3. physiological dead space = sum of anatomical dead space and alveolar dead space

Question 13

where air goes when we breathe

Answer 13

tidal vol = 500mL

1. 350mL => alveolis
2. 150 mL => physiologically dead space

Question 14

inn of respiratory pathways (2)

Answer 14

1. not much sympathetic, epinephrine and nor-epinephrine freely circulate
2. parasympathetic NS- constricts airways, vagus nerve inn and secretes acetylcholine which causes mild -> mod constriction

Question 15

function of nose in respiration (4)

Answer 15

1. nasal cavity is main passaegway for respiratory system
   3 functions:
2. warming and (3) humidifying air to maintain air temp = body temp (trachemosty can lead to infection because air is not humidified)
3. filtering air

Question 16

histology of respiratory membrane (6)
(path for O2 in alveoli -> blood)
(opposite path for CO2 blood -> alveoli)

Answer 16

1. surfactant + water
2. single layer cuboidal epithelium cells
3. interstitial space
4. capillary epithelium
5. capillary endothelium (endothelium = epithelium of bv)
6. RBCs (which are the same size as capillary so they touch the sides, and minimize space O2 needs to travel thru)

Question 17

hemoglobin dissociation curve (1)

Answer 17

1. sigmoid shape shows Hb affinity for O2 increases for every O2 that binds (Hb can bind to 4 O2 at once)

Question 18

diffusing capacity def

Answer 18

diffusing capacity = amt of gas that can move from outside to hemoglobin

Question 19

4 factors that determine how rapidly a gas will pass thru respiratory membrane

Answer 19

1. thickness of membrane
2. surface area of membrane (emphysema)
3. diffusion coeeficient of gas
4. pressure differences across membrane

Question 20

function of Hb

Answer 20

protein that acts as a tissue O2 buffer - maintains constant PO2 in tissues

Question 21

shifts in Hb curve (what it means and 4 causes)

Answer 21

1. shifts to the R = less affinity for O2 (so more goes into tissue/Hb is unloading)
2. from metabolically active tissue
   
   3. temp
   4. PCO2
   5. [H+] increased

Question 22

%s CO2 is transported in blood (3)

Answer 22

1. 7% in plasma
2. 23% Hb
3. 70% carbonic acid/ bicarbonate buffer

Question 23

Respiratory center neurons (and where they are located) (3)

Answer 23

1. Dorsal respiratory group (medulla)
2. Pneumotaxic center (pons)
3. Ventral respiratory group (medulla)

Question 24

dorsal respiratory group

Answer 24

generates inspiration in steady ramp like action (responsible for rhythm of breath)

Question 25

pneumotaxic center

Answer 25

limits duration of inspiration => increases respiratory rate (and filling phase of lung)

Question 26

ventral respiratory group

Answer 26

inactive during normal respiration, can cause inspiration or expiration

Question 27

hering-breuer reflex

Answer 27

1. mechanical reflex that prevents over inflation of lungs b/c stretch receptors

Question 28

chemical factors affecting respiration (3)

Answer 28

1. [H+] = pH = most imporatant
2. [O2] - only as last resort- if really low
3. [CO2]

Question 29

facts about alveolar air (4)

Answer 29

1. partially replaced by atmospheric air with every breath
2. O2 diffusing from alveoli; CO2 => alveoli
3. on expiration, dead space air is first out
4. atmospheric air is humified before hitting alveoli

Question 30

differences btwn alveolar air and PP of gases in blood

Answer 30

1. some O2 is shunted before its oxygenated, so PP btwn arterial and alveolar O2 can differ
2. PN2, CO2, water vapor are constant

Question 31

2 facts about blood distribution and cardiac pathologies

Answer 31

1. systemic circulation has 9x more blood than pulmonay, so any shifts affect pulmonary more
2. stenosis in mitral valve (left side of heart**) => blood accumulating in pulmonary arteries and increase in pulmonary BP