Respiratory system: Regulation of Respiration Flashcards
Eupnea
normal respiratory rate & rhythm
apneustic breathing
prolonged inspirations
- gasping!
apnea
cessation of breathing
hyperpnea
increase in ventilation
ex. after exercise
What are the 3 respiratory centers ? where are they located?
- dorsal respiratory group - medulla
- Pneumotaxic center - pons
- ventral respiratory group - medulla
What does the dorsal respiratory group control?
Inspiration
Where does the DRG get its sensory info from?
afferent from vagus and glossopharyngeal N.
- peripheral chemoreceptors
- baroreceptors
- receptors in lungs
What is the basic rhythm of respiration controlled by the DRG?
- action potentials from DRG ramp up and signal inspiratory mm (diaphragm)
- signals stop suddenly for 3 sec which stops stimulating the diaphragm to contract –> passive recoil
- process repeats
what are the 2 points of control of the respiratory Ramp?
- rate of increase of the ramp signal.
- can occur quickly when needed for rapid breathing - End of ramping
- usual method for controlling rate of respiration
What does the pneumotaxic center do?
signals DRG, determines the “TURN OFF” point of inspiratory ramp –> limits inspiration
What will a strong pneumotaxic signal equal?
short lung filling time (inhibits DRG)
What will a weak pneaumotaxic signal do?
longer lung filling time.
what does limiting the ramp time do?
shortens inspiratory time (and therefore, expiratory time) –> overall increase in breathing rate
What does the VRG- ventral respiratory group do? When is it active?
with increased need for ventilation, VRG contributes to inspiration and expiration (diaphragm& abdominals)
-normally inactive during quiet breathing
What is the Hering Breuer reflex? How does it work?
- Stretch receptors
- in walls of bronchi and bronchioles
- send signals to DRG when overstretched –> turns OFF ramp
- increases respiratory rate
- similar to pneumotaxic center
What is the goal of matching ventilation needs of the body?
What are control mechanisms responsive to?
maintain appropriate 02, C02, H+
- control mechanisms are responsive to these molecules.
Central chemoreceptors respond to acute increased what? Where are they?
C02 & H+
Medulla
_____ is the primary stimulus, but presents across the blood brain barrier as a direct effect of _______
H+
CO2
H cannot cross the blood brain barrier, but CO2 can. This means that the main driver is CO2
what is the process of the chemoreceptors?
increase in blood C02 –> gets into CSF –> reacts with H20 –> forms H+ –> H+ ions stimulate rate and depth of breathing
how long does the increased level of C02 last? What is this due to?
1-2 days
- due to renal readjustment
Change in blood C02 has a ________ acute effect on controlling respiratory drive, but ________ chronic effect after a few days of adaptation
strong
weak
What effect does 02 have on CNS respiratory centers?
no direct effect
How does peripheral chemoreceptor system work? Does it have a rapid or slow response?
What will happen to blood Hgb?
responds to changes in blood 02
- sends signals to DRG
- rapid response to low arterial P02. (especially if P02 falls between 30-60)
- blood Hgb will decrease in this range.
what effect do C02 and H+ have on peripheral receptor response?
much less powerful influence.
- However, peripheral effects of C02 occur 5x faster than central effects. This may be important at onset of exercise.
