Cardio 3.3 Flashcards
what does breathing maintain?
Pa(O2) and Pa(CO2)
what part of the brain stem normally controls the breathing?
medulla and pons
what three groups of neurons in the brain stem normally control involuntary breathing ?
-Medullary respiratory center
-apneustic center
-pneumotaxic center
(latter two are in the pons)
medullary respiratory center contains what neurons?
Dorsal Respritory group (DRG)
The DRG is mainly responsible for what?
inspiration and generation of the basic rhythm for breathing
what provides input to the DRG and what do they do?
CN X- inputs info from the peripheral chemoreceptors and mechanorecperores
CN IX- inputs information from peripheral chemoreceptors
by what means does output from the DRG travel?
The phrenic nerve
the medullary group contains what neurons?
Ventral respiratory Group (VRG)
What does the VRG control?
-primarily responsible for experiration
However, is not active during normal breathing, only during active breathing
how does normal respiration occur?
activation and deactivation of the DRG (active when inspiring, inactive when expiring)
where is the apneustic center located?
lower pons
what does the apneustic center controle?
Prolonged stimulation of inspiration (excites respritory center in medulla prolonging action potentials in the phrenic nerve)
where is the pneumotaxic center located?
in the upper pons
what function does the pneumotaxic center play
inhibits inspiration and limits the burst of action potential in the phrenic nerve (limits the size of the Tidal volume)
true or false, the cerebral cortex can overide the brainstem in order to cause hyper or hypo ventalation
true
hyperventalation can raise pH by decreasing Ps(CO2)
where are central chemoreceptors found?
bilaterally in the ventrolateral medulla
where are the peripheral chemoreceptors found?
The aortic arch and carotid arteries
what stimulii increases the Breathing rate?
Central chemoreceptors
Lower pH
Increased P(CO2)
Peripheral
decreased P(O2)
Increased P(CO2)
decreased pHwhat is the most closely controlled chemical influencing respiration?
CO2 (Normally around 40mmHg, and regulated +/-3mmHG)
what does a decrease in pH in the CSF induce?
An increased breathing rate
what crosses the blood brain barrier more easily
H+ of CO2
CO2
what are peripheral chemoreptor most sensitive to?
arterial O2 (only has a slight inlfuence on ventilation, O2 must be below 60)
What is hypoxic drive
when CO2 is retained due to pulminary disease, thus receptors adapt, and do not react to this stimuluse. declining O2 is the driving force behind respiration
Is it a good idea to give someone with hypoxic drive O2?
NO, this will decrease their breathing
