Session 11_Respiratory system regulation Flashcards
Eupnea =
normal respiratory rate and ryhthm
apneustic breathing =
prolonged inspirations (usually at end of life)
Apnea =
cessation of breathing
Hyperpnea =
increase in ventilation (increase in DEPTH of breathing)
What are the 3 primary groups of neurons making up the brainstem respiratory center:
- dorsal respiratory group (medulla oblongtoa) (DRG)
- pneumotaxic center (pons) - pontine respiratory group (PRG)
- ventral respiratory group (medulla oblongata) (VRG)
PRG has a ______________ stimulation effect on _______ and _______.
negative
VRG and DRG
VRG ____________ stimulates ________________ muscles.
positive
expiratory muscles (intercostals and others)
DRG has an ________________ stimulatory effect on ___________________________________.
positive
Inspiratory muscles (external intercostals and the diaphragm)
The dorsal respiratory group controls _____________.
inspiration
Neurons in the dorsal respiratory group lie in nucleus of the tractus ________________.
solitarius
Neurons in the DRG receive sensory information from the __________ and ______________ nerves. Including signals from ____________________, _________________, and ___________________.
vagal and glossopharyngeal nerves
peripheral chemoreceptors, baroreceptors, and types of receptors in the lungs.
Peripheral chemoreceptors =
choratid and aortic bodies
Which 3 nerves influence inspiration?
vagus, glossopharyngeal and facial
The __________ nerve has senssory vibers in the inner ear; when you clean your ear causes a ______________ sensation.
vagus
coughing
Breathing control centers are located in the:
pons and medulla
Nerve impulse from the _____________ relay changes in CO2 and O2 concentrations to the __________________.
FROM the HEART , TO the BRAINSTEM
Nerve impulses from the brainstem, trigger ________________ of muscles.
contraction
Where is the basic rhythm of respiration set?
primarily in the dorsal respiratory group
Actions potentials from the DRG “___________” and signal the inspiratory muscles (primarily the diaphragm) to contract.
ramp up
From the DRG, signals travel along the ________________________ tracts in the spinal cord to the __________________ and intercostal nerves.
reticulospinal tracts
phrenic nerves and intercostal nerves
Why is “ramp-up” good?
eliminates jagged breath
- a slow and controlled/ even breath is desired
Signals stop suddenly for about ___________ seconds which stops stimulation the ___________________ to contract.
~ 3 seconds
diaphragm
Stopping the diaphragm from contracting provides time for:
passive recoil
Inspiratory ramp = shorter __________–> shorter ______________ –> increased rate
shorter inspiration –> shorter expiration –> increased rate
What are the 2 points of control of the inspiratory ramp:
- rate of increase of the ramp signal
2. end of ramping
Ramp can occur ________ when needed for rapid breathing.
quickly
End of ramping provides limits to the _________________ - usual method for controlling rate of respiration.
time of inspiration
Pneumotaxic center is inhibitory or excitatory? It is a ______________ valve.
Inhibitory
“shut-off” valve
The pneumotaxic center signals the __________ to determine the “turn off” point of the inspiratory ramp; _________ inspiration.
DRG
limits
Strong pneumotaxic signal =
short lung filling time (inhibits DRG)
Weak pneumotaxic signal =
longer lung filling time
Limiting the ramp time shortens the inspiratory time; and therefore the expiatory time –>
overall increases the rate of breathing
VRG neurons normally inactive during:
quiet breathing
With increases need for ventilation, ventral neuron group contributes to ________________ and _______________ via the diaphragm and abdominals.
inspiration and expiration
Mor muscle fibers can be recruited by increasing what/
signals from DRG and VRG as needed (prn)
The ___________ reflex is a lung mechanism for additional control.
Hering-Breuer
In the Hering-Breuer reflex, ____________ receptors function in the walls of ___________________ and ______________.
stretch
bronchi and bronchioles
Stretch receptors send signals to DRG when overstretched, thus _____________.
turning off ramp
When the stretch receptors turn off the ramp, the respiratory rate:
increases
The Hering-Breuer a similar response to the _______________ center.
Pneumotaxic
The stretch receptors appear to function with Vt > ___________________ - as a protective response.
1500ml
When matching ventilation with the needs of the body, the goal is to:
maintain appropriate [O2], [CO2], and [H+] (in blood and tissues)
What are responsive to concentrations of the molecules?
control mechanims
How do we control the respiratory need of the body?
CO2, O2 and H+
In respiration, the effect of changes in CO2 and H+ in blood concentrations and tissues produces a _______ effect on respiration. O2 is ___________.
DIRECT
INDIRECT
The O2 plays a role in whether respiratory rate is increased because of the peripheral ___________________ located in carotid and aortic bodies. When the carotid and aortic bodies sense a lack of oxygen, they will stimulate the respiratory center (___________) (indirect effect).
chemoreceptors
DRG
What are the 3 areas of the respiratory center are not directly affected by the increase H+ and CO2?
DRG, Pneumo, and VRG
Where is the chemosensitve area?
additional in the medulla
How is the chemosensitive area affected by changes in blood PCO2 or H+?
It is strongly affect; H+ is the primary stimulus but presents across the blood brain barrier as a direct effect of CO2
*stimulates other parts of the respiratory center
Which crosses the BB more easily, CO2 or H+?
CO2 crosses more easily than H+
Change of PCO2 is the ___________ driver for determining respiratory rate or control?
primary/ main
CO2 + H2O = HCO3 ==> HCO3- + H+
H+ goes across stimulates _________________ area, which the stimulates ___________ area to send signals down to muscle to contract.
chemosensitive
inspiratory
increased arterial PCO2 –>
• increased PCO2, decreased pH in cerebrospinal fluid
• peripheral chemoreceptors (carotid and aortic bodies mediate 30
5 of the response)
• increased PCO2, decreased pH in cerebrospinal fluid –>
central chemoreceptors in medulla (mediate 70% of the response)
peripheral chemoreceptors (carotid and aortic bodies mediate 30 5 of the response) -->
Medullary respiratory centers (afferent impulses)
central chemoreceptors in medulla (mediate 70% of the response) –>
Medullary respiratory centers (afferent impulses)
Medullary respiratory centers (afferent impulses) –>
respiratory muscles (efferent impulses)
respiratory muscles (efferent impulses) –>
increases ventilation (more CO2 exhaled)
increases ventilation (more CO2 exhaled) –>
arterial PCO2 and pH return to normal
Long-term control of excitation by CO2; effect of increased CO2 decreases over:
subsequent 1-2 days (RENAL readjustment)
Bottom line, change in blood CO2 has strong __________ effect on controlling respiratory drive but weak ____________ effect after a few days’ adaptation.
strong ACUTE
weak CHRONIC
In COPD problem is blowing CO2 ______.
out
meaning, COPD blood gasses skewed.
In the respiratory control, oxygen has __________ effect.
NO DIRECT
Oxygen-hemoglobin buffer system ensures:
adequate O2 delivery through wide range of PO2
In pts with COPD, do a blood gas:
draw blood to find out what the PO2 and PCO2 is.
Use in hospital with pts having difficult breathing, getting confused, draw blood so analyze their level. BUT pt with COPD, blood gases skewed.
If PO2
special control response occurs;
Tells body to increase breathing, to increase oxygen coming in.
Mechanisms to assure O2 delivery when blood O2 ______________.
falls too low
CO2 has different buffer system;
CO2 changes according to ventilation
change in CO2, change in RR –> CO2 primary driver in respiration.
The peripheral chemoreceptor system primarily responds to changes in blood ______.
O2
The peripheral chemoreceptor system transmits nervous signals to what system?
Respiratory center (DRG)
What CN is sending sensory info from carotid bodies?
glossopharngeal
What CN is sending sensory info from aortic bodies?
vagus
The peripheral chemoreceptors system has a rapid response to low arterial PO2; especially if PO2 falls between ________________.
30-60mmHg
What happens to Hgb saturation at 30-60mmHg?
decreased, (~15mmHg) losing affinity of hemoglobin to hang onto oxygen.
The CO2 and H+ peripheral receptor response is much less powerful than the _________________ on the respiratory center.
direct effects
However, peripheral effects of CO2 occur ~5x _________ than central effect.
faster
important role at onset of exercise
…. direct more powerful but time intensive
Pain can ________ RR.
increase
When start EX, have need for increased O2, thought that __________________ are responsible for the response.
peripheral receptors
The higher brain centers, cerebral cortex have _______________ control over breathing.
voluntary
Other receptors (e.g. pain and emotional stimuli act through:
hypothalamus
Peripheral chemoreceptors:
O2 decrease, CO2 increase, H+ increase
Stretch receptors in ____________ have an affect.
lungs
prevent overfilling; have inhibitory affect on PRG
Central chemoreceptors:
CO2 increase, H+ increase
Irritant receptors:
irritant of bronchioles may cause you to cough
________ PO2 effects on Ventilation when CO2 and H+ ______________.
Low
kept constant
PCO2 at normal of 40mmHg, arterial PO2 as gets lower, fairly constant until:
have huge drive to increase ventilation
~60mmHg
Ventilation doubles when arterial PO2 falls to?
~60mmHg
Arterial oxygen huge driver, examples?
altitude
respiratory center loses 4/5 ____________ in high altitude EN.
(changes in PCO2 and H+ over 2-3 days)
sensitivity
DRG doesn’t get stimulated to shut off.
Excess ventilation reducing CO2 would then inhibit an increase in respiration ________.
fails
Low O2 can drive system to high level of ________________.
alveolar ventilation
alveoli become wayyy more efficient
During EX, brain may initially stimulate respiratory center in brainstem when sending motor impulses to the working muscles =
“anticipatory stimulation”
After 30-40 seconds, CO2 is released from active muscle cells and just about matches:
ventilation rate to keep values ‘normal’
Learned response?
EX over time, effect happens more easily vs if you just began training (more short of breath right away).
What are other influences on ventilation?
- pain (hypothalamic control)
- pulmonary irritant receptors (trachea, bronchi, bronchioles, lung receptors)
- Proprioceptors (motion of limbs)
- brain edema (if brain is swollen will compress cerebral blood supply –> depressing respiratory center)
- anesthesia (depresses respiratory system; too may narcotics, need narcan)
- ANP (peptide hormone; inhibits vasoconstriction and water retention –> decreasing BP –> decreases PO2 by decreasing blood flow)
Hyperventilation =
increase in rate and depth of breathing (exceeds need to remove CO2)
Low blood CO2 (hypocapnia) causes:
cerebral vasoconstriction
What is the result of cerebral vasoconstriction?
get dizzy and pass out
What is the treatment for cerebral vasoconstriction?
Give them a bag, so that CO2 being breathed off, is trapped and they will breath back in
In pulmonary disease, retention of ______ can occur.
CO2
example: emphysema (or any obstructive disease)
PCO2 is chronically _______________ in pulmonary disease.
chronically (CO2 and PO2 flip roles; O2 becomes main driver for respiration)
… chemoreceptors are adapting
Reduced PO2 acts on peripheral chemoreceptors and provides main stimulus for respiration =
hypoxic drive
What would be the result of giving pure oxygen to an individual with emphysema?
body wont to recognize need to increase ventilation
- Why is CO2 the primary driver for the control of respiration?
???
CO2 able to cross BB, converted to H+ which change CSF
- How do the peripheral chemoreceptors effect control of respiration?
???
primarily respond to O2.
If low O2 send signals up to DRG to increase breathing rate
- How does central chemoreceptors affect respiration?
???
Depends on amount of CO2; sends afferent info to medulla chemosenstive center, which sends back down efferent info to intercostals diaphragm.
- How do the DRG, PRG and VRG affect respiratory control?
??? Directly VRG targets intercostals DRG targets diaphragm and intercostals PRG inhibiting the DRG At rest PRG dominates ???????? PRG - inhibitor VRG - overdrive DRG -main controller
- How does O2 levels drive the system to higher levels of alveolar ventilation at high altitude?
???
Lower PPO2 causes chemoreceptor and baroreceptors to facilitate higher ventilation rate to cause PPO2 to return to more normal rate. At altitude have less oxygen, baroreceptors more quick acting, chemorecptors cause stronger, long term affect .
