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KP322 > respiratory system > Flashcards

respiratory system Flashcards

1
Q

respiratory zone

A

300 mil alveoli, HUGE SA

rapid exchange b/w alveoli are 1 layer thick

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2
Q

respiratory membrane

A

thin memb enhances exchange

SA for excahnge
alveoli close to blood

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3
Q

mechanics of breathing

A

active process of musc contraction

airflow bcs of pressure gradients

inspiratiory muscles act as pump
- lungs expand
- pleural fluid

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4
Q

active vs passive respiration

A

active resp: during exercise
- abdominal muscles engaged

inspiration: in/external intercostals, diaphragm

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5
Q

boyle’s law

A

as volume dec, pressure inc

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6
Q

what does airway resistance depend on

A
  1. pressure difference
  2. resistance of airwats

airflow: p1-p2/resistamce

airway resistance depends on DIAMTER

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7
Q

Vt

A

tidal volume

amount of air moved/breath

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8
Q

f

A

breath frequency

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9
Q

V

A

amount of air moved by the lungs/min

Vt x f

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10
Q

Va

A

alveolar ventilation

volume of air that reaches respiratory zone

VA = (VT - VD) x f

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11
Q

Vd

A

dead space ventilation

volume of air remaining in conducting aiways

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12
Q

how can V be calculated

A

V = VA + VD

V = VT x f

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13
Q

VE

A

minute ventilation

air flow/each…how much air breathed and breaths/min

VE = Vt x f

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14
Q

lung volumes

A

4 volumes and 4 capacities to diagnose issues

resting tidal volume/VT: vol of normal breath, 500ml

ERV: max are expirated at end of normal expiration, 1000ml

IRV: max air inspired at end of normal inspiration, 3300ml

RV: air left in lungs after max exhalation, 1200ml

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15
Q

FVC

A

max volume stroke of lungs

force air out of lungs

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16
Q

what does dynamic ventilation depend on

A
  1. FVC
  2. speed of moving a volume of air/breathing rate
    - determined by lung compliance/resistance of respiratory passages
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17
Q

FEV1

A

forced expiratory volume, measured over 1 second
- when divide by FVC, indicates pulmonary airflow capacity

85% = healthy
70% or lower unhealthy

FEV1/FVC x 100%

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18
Q

sex differences

A

women have dec lung size, airway diameter, static/dynamic lung function

leads to expiratory flow limitations
- inc musc work
- inc resp reserve during max exercise
- dec lung vol, inc expiratory flow in trained women

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19
Q

air composition

A

0.03% co2
79% n2
21% o2

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20
Q

dalton’s law of partial pressure

A

each gas contributes to total pressure proportionately to its number of molecules

partial pressure = total pressure x gas fraction

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21
Q

henry’s law of gas exchange

A

when gas mixes w liquid, each gas will dissolve w proportion to its partial pressure gradient and solubility coefficient

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22
Q

partial pressure in alveoli

A

tracheal air becomes saturated w water vapur as passes down conductive zone

water molecules disperse gas molecules
- inc total volume of air, bcs add water and gas
- dec gas pressure for given vol of air

23
Q

factors affecting gas exchange

A
  1. partial pressure gradient across barrier
  2. diffusion capacity: solubility of gas
  3. characteristics of barrier: SA and thickness

CO2 more soluble than O2

24
Q

ventilation-perfusion ratio

A

ratio of alveolar ventilation : pulmonary air flow
- 1 is idea, matches rate

4.2 L air ventilates alveoli/min of rest
5 L of blood flow in capillaries

avg V:P is 0.84…..VA or 0.84L matches 1L of blood flow

high value = too much VE
low value = too much BF

this ratio DECREASES W INTENSE EXERCISE

25
Q

o2 transport in blood

A

99% o2 bound to hemoglobin
- amount transported depends on hemo concentration

normal hemo concrentration is 15%
- each hemo transports 1.34ml o2

hemoglobin conc shown in g/100ml

26
Q

where else is o2 dissolved

A

small amount o2 dissolved in plasma

3ml/L

27
Q

things that impact o2 transport

A
  1. pH: inc H will weaken o2 and hemo bond, leads to unloading
    - right shift via Bohr effect
    - more o2 delivery
  2. temperature: inc temp leads to unloading
    - right shift
  3. 2,3 DPG: present in RBCs, is anaerobic energy
    - 2,3 DPG binds to hemo, reduce hemo o2 affinity
    - left shift, dec o2 transport
    - only during exercise at altitude or low hgb
28
Q

myoglobin

A

facilitates o2 transfer to mitochondria
- cellular PO2 dec rapidly but myoglobin RETAINS high o2 saturation

higher affinity to o2, bcs has iron

greatest amount of o2 releases from myoglobin when tissue PO2 drops below 5mmhg

binds to o2 at low PO2

acidity, co2, temperature do NOT affect myoglobin’s o2 affinity

29
Q

a-v o2 difference cont

A

difference b/w o2 content of arterial blood and mixed venous blood
- difference becomes GREATER W EXERCISE

active musc has high capacity to use o2

o2 supply limits aerobic capcity, NOT musc o2 use

30
Q

co2 transport in blood

A

70% converted to bicarbonate to move thru blood

co2 + h2o –> h2co3 –> H + HCO3 (bicarbonate)
- via carbonic anhydrase

10% dissolved in plasma

20% bound to hemoglobin

31
Q

co2 bicarbonate transport

A

at tissue:
- H binds to hemoglobin
- HCO3 diffuses out of RBC into plasma
- chloride shift when Cl diffuses into RBC

at lung:
- o2 binds to hemoglobin, drives off H
- rxn reverses and releases co2

32
Q

acid-base balance

A

pulmonary ventilation removes H from blood by HCO3 rxn

inc VE results in co2 exhalation
- dec PCO2 and H conc
- ph inc/basic

dec VE results in buildup of co2
- inc pco2 and h conc, more acidic

33
Q

rest-to-work transitions

A

when constant load, submaximal exercise:
- VE inc rapidly initially, then slow to steady state

PO2 and PCO2 relatively unchanged

increase in alveolar ventilation is slower than inc in metabolism

34
Q

ventilatory equivalent

A

ratio of gas expired/min to volume o2 consumption/min

VE/VCO2

has linear relationship during light/mod exercise
- up to 55% vo2 max

remains constant during steady state exercise

prolonged exercise in heat will inc VE, but not inc CO2
- inc blood temp will affect respiratory control centre

35
Q

non-steady state exercise

A

VE inc proportionately to VO2

as intensity inc, VE disproportionately increases compared to VO2
- VE/VO2 can reach 40L

36
Q

incremental exercise

A

in untrained ppl:
- linear inc, initial 50-75% vo2max
- after this, exponential rate (ventilatory threshold)

in elites:
- VT occurs at higher percentage of vo2max
- PO2 dec to 30-40mmHg, hypoexmia
- bcs ventilation/perfusion mismatch, short RBC transit time and high CO

37
Q

ventilatory threshold

A

inflection pt where VE inc exponentially

bcs co2 release from lactic acid

elite athletes will reach VT later

38
Q

where does VE inc the most in breathing

A

tidal volume

39
Q

control of ventilation at rest

A

inspiration is active, expiration is passive

resp muscles controlled by somatic motor neurons in spinal cord

activity of motor neurons controlled by respiratory control centre in medulla oblongata

40
Q

respiratory control centre

A

in brain stem:
- medulla oblongata, connected to SC and brainstem
- pons

41
Q

3 distinct rhythm centres of RCC

A
  1. prebotz: inspiration
    - interacts w other centres at rest of reg breathing
  2. RTN/PFRG: expiration
  3. pontine resp centre: rate and pattern

all act as pacemaker of breathing rate

normal rhythm bcs of interactions b/w clusters

42
Q

where does RCC get info from

A

from higher brain centres/neural input and periphery/humoral input

43
Q

humoral input

A

input from periphery

chemoreceptors: specialized neurons detect changes in environ/blood

central chemoreceptors: in medulla, detect pco2, h concentration, CSF

peripheral chemoreceptors: aortic arch and common carotid artery…detect PO2, PCO2, H, K in blood

44
Q

neural input

A

from higher brain centres and afferent pathways

motor cortex alters breathing in proportion to exercise

afferent input from muscle spindles, GTOs, joint pressure receptors

important in reg breathing during submax and steady state

45
Q

what is greatest respiratory stimuli during rest

A

PCO2 in arterial blood
- small inc in PCO2 in inspired air causes large inc in VE

stimulates both central and peripheral chemoreceptors

ph affects VE:
- acidosis reflects CO2 retetnion
- breathing inc to remove co2

46
Q

plasma o2 and VE

A

changes in PO2 have small effect on VE

environ changes that dec o2 will stim PERIPHERAL CHEMORECEPTORS ONLY
- carotid bodies
- monitor arterial blood as moves to brain, protect against dec PO2

stim ventilation during exercise to:
- inc temp
- inc acidity

47
Q

types of peripheral chemoreceptors

A

aortic body: detects inc PCO2 and ph
carotid body: detects inc PCO2, dec PO2, and ph

will inc VE

48
Q

cortical influence

A

anticipation of exercise stimulates respiratory neurons in medulla

rapid inc in VE

49
Q

peripheral influence

A

sensory input from joints, tendons, muscles

influences ventilatory adjustments to exercise

50
Q

ventilatory control during submax vs heavy exercise

A

submax exercise:
- primary drive is higher brain centres/central command
- fine tuned by humoral and neural input

heavy exercise:
- linear inc in VE
- bcs inc H in blood stims carotid bodies

51
Q

integrated regulation of ventilation during exercise

A

simultaneous effects of many chem and neural stimuli

phase 1: start exercise, neurogenic stim from cerebral cortex and feedback from active musc stims medulla to ABRUPTLY inc VE
- neural

phase 2: after short plateau, VE rises exponentially to achieve steady lvl
- humoral

phase 3: fine tuning of steady state ventilation thru peripheral feedback

recovery: gradual dec of short term potentiation of resp centre

52
Q

training effects on respiratory muscles

A

no effect on lung structure or function at rest

normal lung is capable of meeting gas exchange demand
- don’t need adaptation for homeostasis

elite endurance athletes experience hypoexmia
- bcs lungs fail to adapt to training
- FATIGUE at greater than 90% vo2max

53
Q

maximum voluntary ventilation

A

rapid and deep breathing for 15s, extrapolate to 1 min
- eval ventilatory capacity

exercise doesn’t maximally stress healthy person

trained resp muscles:
- inc endurance
- inc max voluntary vent
- inc inspiratory musc function

KP322 (7 decks)

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