Respiration parts 7 - 10 Flashcards
a rhythmic pattern of breathing is established by cyclic ______ activity to the respiratory mm.
neural
what are the 3 respiratory centers of the brain stem and which is the primary center?
- medulla (primary)
- Apnustic center
- Pneumotaxic center(influences output from the medulla)
the medulla is composed of 2 groups (clusters) what are they and what are they composed of?
- Dorsal Resp group (DRG) - the inspiratory center composed of inspiratory neurons.
- Ventral Resp Group (VRG) - the expiratory center and also composed of inspiratory neurons. - DRG has connections to it.
the inspiratory center receives input from ______ _______ via CN IX (glossopharyngeal) in the carotid aa. and the ________ via CN X (vagus nerve) in the lungs
peripheral chemoreceptors
machanoreceptors
the DRG sends motor output to the _______ via CN VII (phrenic nerve) and to the external intercostal mm via ________ nerves.
diaphragm
intercostal nerves
the result of the DRG simulating contraction of the diaphragm and external intercostal mm is what?
the active process of inhalation occurs - air if forced to flow in
the VRG is responsible for _______ but is inactive during quite breathing because it is a passive process.
exhalation
air is forced out of the lungs by a reverse in the ____ _____ between the lungs and the atmosphere until the system achieves an equilibrium point.
pressure gradient
the VRG is activated by the ______ as an overdrive mechanism during periods when demand for ventilation are increased.
DRG - creates active exhalation
Only during _____ expiration do the expiratory neurons stimulate the motor neurons supplying the expiratory mm. (internal intercostals & abdominal)
active
the _______ center is responsible for the activation of the expiratory center involvement when ventilation demand is high.
inspiratory center
the Pneumotaxic & Apnustic Centers located in the Ponds of the brain stem help to ______ ______ the medulla/DRG to produce a normal smooth inspiration and expiration.
Fine tune
The pneumotaxic center transmits ____ _____ to the DRG that help limit the volume of air inspired per breath.
inhibitory impulses
the Apneustic center is responsible for making sure the _______ ______ are never switched off. thus, provides a boost to the inspiratory center’s drive.
inspiratory neurons
in a check-&-balance system, the pneumotaxic center is _______ over the apneustic center, helping to bring inspiration to a halt and allowing expiration to occur normally
dominate
the medullary respiratory center, in response to changing metabolic O2 & CO2 needs can adjust the _______ & _______ of respiration to keep arterial gas values WNL.
rate & depth
what are the 3 most important factors that increase ventilation?
- increase in arterial PO2
- increase in arterial PCO2
- increase in H+ conc
the body has two sets of chemoreceptors what/where are they?
peripheral chemoreceptors in carotid aa & aortic arch
central chemoreceptors in the medula
chemoreceptors are specialized ______ that respond to changes in chemical levels the body.
Organs
________ chemoreceptors are not sensitive to modest reductions in arterial PO2. thus, to activate this receptor PO2 must fall below 60mmHg.
peripheral
________ chemoreceptors link changes in PCO2 to compensatory adjustments in ventilation.
central
T/F
central chemoreceptors monitor CO2 directly.
False biotch!
they monitor CO2 induced H+ concentrations in the ECFof the brain that baths them
a decrease in pH of CSF will _________ breathing rate.
increase
which chemoreceptor play a role in adjusting ventilation in response to alterations in arterial [H+] unrelated to fluctuations in PCO2?
peripheral
- [H+] can rise from fat –> ketone breakdown. the H+ produced this way can NOT cross the BBB thus the drop in pH from the rising [H+] will activate the peripheral chemoreceptor and increase ventilation
mechanoreceptors (stretch receptors) are present in the _______ _____ of airways and respond to stretching during inhalation.
smooth m
Hering-Breuer reflex prevents ______-_______ of the lungs via negative feedback system to inhibit the inspiratory neuron
over-inflation
proprioceptors located in muscles n joints send inputs to the _______ respiratory center to aid in coordinating respiratory activity. (increase metabolic activity of mm = increase RR)
medullary
irritant receptors for noxious chemicals and particles located between ________ cells lining the airways.
epithelial
stimulation of irritant receptors travel to the medulla and cause a reflex _______ of the bronchial smooth m with an increase in _____ _______.
constriction
RR
Juxtacapillary receptors or J receptors are located in alveolar walls near the capillary. how can they be stimulated to increase RR? what could be a possible cause for the stimuli.
name it fool!
engorgement of the pulmonary capillary and the increase in ISF that results
one possible cause is CHF (L side) will cause pulmonary congestion.
with increasing altitude the result on Hb saturation is?
% Hb saturation declines with increasing altitude = Left shift of curve.
what are 4 adaptive responses to increasing altitude?
- hyperventilation = increase gas exchange
- polycythemia = increase PCV
- increase 2,3 BPG production = decrease in Hb affinity for O2 at tissue level
- can increase capillary density in tissues = improved gas exchange with blood n tissues
- increase mitochondria density = increase ATP synthesis
- increase m myoglobin content = increase O2 stored in m => increase rate of O2 transfer to m fibers from blood
what is the difference between hypoxia and hypoxemia?
hypoxia - is a decrease in O2 delivery/utilization by tissue
hypoxemia - a decrease in arterial PO2
name 3 general causes of hypoxia.
- hypoxemia - a decrease arterial PO2 ie high altitude
- pulmonary dz - chronic bronchitis; pulmonary fibrosis; pulmonary edema
- inadequate O2 transport to tissue via blood
pulmonary dz resulting in hypoventilation can be caused by?
Chronic bronchitis = mucus build up causing increase airway resistance
Pulmonary fibrosis = CT build up decreases compliance lowering title volume
Pulmonary edema = diminished respiratory membrane diffusion.
name 5 ways hypoxia can result from inadequate O2 to tissues.
- anemia - lack of carrying capacity
- CO poisoning - decreases P50 by 1/2
- general circulatory deficiency = decreased CO
- localized circulatory deficiency (Ischemia) = obstruction to blood flow
- Tissue edema = reduces gas transfer between the blood and the tissues
- histotoxic hypoxia - ie cyanide = interferes with O2 utilization by tissue
what is histotoxic hypoxia? what makes it different than other anemia’s?
a poisoning of cellular oxidative enzymes. its different because it doesn’t involve decreases in blood flow or Decreased O2 content.
