respiratory 4 Flashcards
ventilation has 4 potential sites of control:
these control the ___ and ___ of ventilation
CNS respiratory control center
peripheral chemoreceptors
central chemoreceptors
mechanical (stretch) receptors in lung
rate & depth
CNS respiratory control center:
ventilation is a vital reflex, so its controlled by ___ and ___
there are diff groups of neurons that contain all the neurons that control rate & depth of breathing:
medulla oblongata & pons
ventral respiratory root, VRG, dorsal respiratory root, DRG
name the 3 types of neurons in the CNS respiratory control center
1- pacemaker neurons: depolarize and fire spontaneously at their own natural rhythm
2- inspiratory neurons: send signals to the respiratory muscles (diaphragm & intercostal muscles), they initiate inhalation
3- expiratory neurons: they shut off the action of the inspiratory neurons and allow the lungs to passively exhale
CNS respiratory control center:
pacemaker neurons make up a central pattern generator, there are a network of pacemaker neurons located in the ___, they set the rhythm for the beginning of the ___ cycle and once they fire, send signals to the ___
preBotzinger complex
inhalation
inspiratory neurons
CNS respiratory control center:
there are 2 groups of inspiratory neurons, one in the ___ and other in the ___, the lungs fill and then…
Botzinger complex
rostal position
expiratory neurons stop the firing
CNS respiratory control center:
normal respiratory rhythm is altered by a number of factors, ___, other neuronal signals can override the normal rhythm to change it…
speech
DRG has both inspiratory & expiratory neurons, believed to function in overriding normal neural signals during transition from rest to exercise (responsible for overinflating lungs & actively exhaling for exercise)
VRG has diff neurons
- pons adds another layer to ventilation
CNS respiratory control center:
inspiratory neurons stat firing ___…
slowly, their frequency and intensity builds & builds –> then expiratory neurons turn on and inspiratory turns off immediately
CNS respiratory control center:
group of neurons in the pons called ____, there are 2 groups, they each exert a more fine control over the ___ and ___
pontine respiratory neurons
inspiratory & expiratory neurons (and help set the max lung volume)
name the 2 centers in the pontine respiratory center
1- pneumotaxic center: sends impulses to DRG to switch off inspiratory neurons, limiting duration of inspiration (turns them off)
2- apneustic center: does opposite, prevents inspiratory inhibition during period of exercise, allows for increased respiratory drive, allows overinflation of lungs
- allows for recruitment of DRG to function more actively during exercise
the pontine respiratory center is also the receiver for ___….it also receives ___ from the ___, which alters…
sensory info that comes from multiple sources, integrates the input
emotional signals from hypothalamus which alters breathing rate depending on emotional state
chemoreceptors (both central & peripheral) monitor ___, ___, and ___ of your blood
PO2, CO2, and pH
name the 2 locations that peripheral chemoreceptor centers are
1- aortic arch in aortic bodies
2- carotid bodies
peripheral chemoreceptors:
the ones in aortic arches monitor the ___ of your blood, in normal conditions, they are ___…
PO2, silent
only become active in extreme cases, when arterial PO2 levels drop to 60mmHg or below
peripheral chemoreceptors:
the ones in carotid bodies, in the carotid sinus, the same place as ___, they are sensitive primarily to ____
baroreceptors
pH, hydrogen ions
peripheral chemoreceptors:
the ones in carotid bodies monitor minute to minute changes in ___ and adjust ventilation maintain constant ___, they are __ active
arterial pH
pH
always active
peripheral chemoreceptors:
ones in carotid bodies, they can control pH of blood by controlling levels of __ in blood…
CO2, if CO2 builds up in blood –> more hydrogen ions –> more acid pH –> if hyperventilate and blow out CO2, raise pH
peripheral chemoreceptors in carotid bodies are made of 2 types of cells:
type I & type II cells
type II cells are there for support, type I cells are the sensors (sense changes in protons), type I are connected by gap junctions, signals sent very quickly
peripheral chemoreceptors in carotid bodies:
ventilatory rate is controlled by amt of ___ and ___ in blood, not by amt of ___…
CO2 and protons(pH)
oxygen, O2 so abundant in air, never have trouble getting it into blood
remember CO2 is 28x more water soluble, so it’s more difficult to get it out of blood and into lungs to excrete
peripheral chemoreceptors in carotid bodies:
if arterial oxygen goes from normal (100mmHg) to 60mmHg, still plenty of oxygen, but…
if change arterial CO2 by just a little, will change ventilatory rate by a lot (very sensitive to CO2)
central chemoreceptors:
located in the ___ and they lie between the ___ in the ___ and the ___
the monitor…
medulla oblongata & lie b/w the capillaries in the brain and the cerebrospinal fluid
monitors pH of cerebrospinal fluid- this is an indirect way of monitoring pH of blood of the capillaries that feed the brain
central chemoreceptors:
__ themselves cannot pass the blood-brain barrier, but ___ is a nonpolar gas which diffuses across the barrier and into CSF….
what enzyme helps with detection?
protons
CO2
in CSF, there is carbonic anhydrase which converts CO2 to bicarbonate and protons- this change in protons in the fluid reflects the pH of the blood (it is this proton that gets detected by the central chemoreceptor)
stretch receptors in the lung:
there are 2 classes:
slow adapting stretch receptors
fast adapting stretch receptors
stretch receptors in lung:
slow adapting are located in ____, they fire when…
they are believed to set the….
smooth muscle of the bronchioles
fire when lung is inflated (as lung expands more, they fire more)
believed to set the max volume of the lung
stretch receptors in lung:
fast adapting located in ___, they respond to ___ of the lung
outer layer of airways
flexibility (specific role unknown)
stretch receptors of the lung are the bases of the ____ - overexpansion of the lung results in…
harry broyle reflex
slowing down of breathing (more you expand lungs, more the receptors are activated and the more they disrupt the normal firing of inspiratory neurons)
the deeper you breathe, the slower you breathe
whats the name of the pain receptor in the lung?
J-receptors - if your sprint, lungs will burn
- responds to violent increases in pressure
the more you increase in altitude, the less oxygen there is in the environment: ___ slows, ___ goes down, ___ of the brain changes…
reaction time slows
learning & memory goes down
white matter of brain changes
hallucinate & lose consciousness
adaptations to high altitude that help:
___ increases, which helps get more oxygen out of thinning air, ___ levels go up, so there are more RBCs and pack more of it in RBCs; ___ levels increases…
hematocrit
hemoglobin
2,3-DPG levels increases, shifts oxygen curve to right, lowers oxygen affinity for hemoglobin, makes it easier for hemoglobin to deliver O2 to tissues
___ reflex in infants when their faces are emerged in cold water - they immediately stop ___, ___ slows down, and they shunt blood to…
dive reflex
stop breathing, heart rate slows down, shunt blood to 2 vital organs- brain & heart and shunt blood away from skeletal muscle to survive anaerobically
the dive reflex is the ___ system being activated, by stimulation of the ___ nerve – results in a ___ pathway
parasympathetic
trigeminal nerve
trigeminocardiac pathway (stops breathing & heart)
