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Flashcards in Physiology of Respiration Deck (30)
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1
Q

Eupnea definition

A

normal breathing, normal respiratory rate and rhythm

2
Q

apneustic breathing

A

gasping

indicative of end of life

3
Q

apnea

A

stoppage of breathing

4
Q

hyperpnea

A

increased ventilation

  • occurs normally with exercise
  • increased rate, rhythm, depth of breathing
5
Q

brainstem respiratory center

  • primary groups of neurons
  • location of each
A
dorsal respiratory group (DRG)
-medulla
pneumotaxis center (PRG)
-pons (pontine respiratory group)
ventral respiratory group (VRG)
-medulla
6
Q

DRG

  • function
  • neurons lie in…
A

control of inspiration

neurons line in nucleus of the tractus solitarius

7
Q

DRG

-receive sensory information from _____ nerves, including signals from…

A
vagal and glossopharyngeal nerves
signals from
-peripheral chemoreceptors
-baroreceptors
-types of receptors in the lungs
8
Q

basic rhythm or respiration

  • primarily set in…
  • how does it occur?
A

primarily set in dorsal respiratory group
APs from the dorsal respiratory group “ramp up” and signal the inspiratory muscles (primarily the diaphragm) to contract
-signals travel along the reticulospinal tracts in the spinal cord to the phrenic nerve and intercostal nerves
signals stop suddenly for about 3 seconds which stops stimulating the diaphragm to contract - time for passive recoil

9
Q

basic rhythm of respiration

-why is the “ramp up” good rather than all APs being sent at once?

A

allows for gradual inspiration

10
Q

inspiratory ramp

  • what are the 2 points of control of the ramp
  • how can these points be manipulated
A

rate of increase of the ramp signal
-ramp can occur quickly when needed for rapid breathing
end of ramping
-provides limit to time of inspiration - usual method for controlling rate or respiration

11
Q

pneuotaxic center

-function

A

signals DRG

-determines the “turn off” point of the inspiratory ramp; limits inspiration

12
Q

strong pneumotaxic signal =

A

short lung filling time

13
Q

limiting the ramp time _____ the inspiratory time and _____ the expiratory time
-this leads to

A

shortens inspiratory, shortens expiratory

overall increase rate of breathing

14
Q

VRG

-when is it active

A

normally inactive during quiet breathing
with increased need for ventilation, ventral neuron group contributes to inspiration and expiration
-diaphragm
-abs

15
Q

how can respiratory muscle fibers be recruited

A

increase signals from DRG to VRG

16
Q

what is the Hering-Breuer Reflex

-when is it active?

A

stretch receptors in the walls of bronchi and bronchioles send signals to DRG when overstretched
-turns off ramp
this increases the respiratory rate, similar to the response of the pneumotixic center
appears to function with tidal volume > 15500 mL
-protective response

17
Q

what molecules are we primarily concerned with when it comes to regulating ventilation

A

CO2
O2
H+

18
Q

acute effect of increased CO2 and H+

  • what area is primarily affected
  • -what is the primary stimulus
  • -what happens as a result?
A

chemosensitive area

  • in the medulla
  • strongly affected by changes in blood PCO2 or [H+]
  • -[H+] primary stimulus but presents across the blood brain barrier as a direct effect of [CO2]
  • stimulates other parts of the respiratory
19
Q

how does H+ get into the medulla?

A

CO2 + H2O –> H2CO3- –> H+ + CO3-

20
Q

long-term control of excitation by [CO2]

A

effect of increased [CO2] decreases over subsequent 1-2 days

  • renal adjustment
  • -released bicarbonate
21
Q

bottom line for regulation of [CO2]

A

change in blood [CO2] has strong acute effect on controlling respiratory drive but weak chronic effect after a few days’ adaptation

22
Q

role of oxygen in respiratory control

A

no direct effect on respiratory center
oxygen-hemoglobin buffer system ensures adequate O2 delivery through wide range of PO2
there are mechanisms to assure O2 delivery when blood O2 falls too low

23
Q

peripheral chemoreceptor system

  • primarily respond to…
  • transmit signals to…
  • rapid response to…
A

primarily respond to changes in blood O2
transmit nervous signals to the respiratory center (DRG)
vagus takes signal from aortic bodies
glossopharyngeal takes signal from carotid bodies
rapid response to low arterial PO2
-especially if PO2 falls between 30-60 mmHg

24
Q

[CO2] and [H+] peripheral receptor response

  • how strong?
  • how fast?
  • -why might this be important
A

much less powerful than their direct effects on the respiratory center
peripheral effects of CO2 occur 5x fast than central effects
-might offer important role at onset of exercise

25
Q

regarding respiration, how do we adapt to high altitude

A

respiratory center in brainstem loses 4/5 of sensitivity to changes in PCO2 and H+ over 2-3 days
excess ventilation reducing CO2 that would then inhibit an increase in respiration fails
low O2 can drive system to high level of alveolar ventilation

26
Q

brain’s response to exercise in regards to ventilation

A

may initially stimulate respiratory center in brainstem when sending motor impulses to the working muscles
-termed “anticipatory stimulation”
after 30-40 seconds, CO2 released from active muscle cells approximately matches ventilation rate to keep values “normal”
brain can have a learned response so you can accommodate quicker

27
Q

other influences on ventilation

A
pain
-hypothalamic control
pulmonary irritant receptors
-trachea, bronchi, bronchioles
-lung receptors
proprioceptors
-motion of limbs
brain edema
anesthesia
ANP (atrial natriuretic peptide)
-increases ventilation
28
Q

hyperventilation

  • what is it
  • low blood CO2 causes…
  • quick treatment
A
increase in rate and depth of breathing
-exceepds need to remove CO2
low blood CO2 (hypocapnia) causes cerebral vasoconstriction
Tx
-breathe into bag
29
Q

pulmonary disease

  • what con happen to [CO2}
  • example
A
retention of CO2 can occur
Emphysema
-PCO2 chronically elevated
--chemoreceptors adapt
--therefore, reduced PO2 acts on peripheral chemoreceptors and provides main stimulus for respiration = hypoxic drive
30
Q

why not give someone with COPD supplemental oxygen

A

they have elevated CO2 levels, so the main drive of their respiration is low O2 levels
giving them supplemental O2 means they stop breathing, which increases CO2 even more