Respiratory System 5 Flashcards
what controls and innervates breathing
innervated by smooth muscle and glands that are innervated by axons of lower motor neurons of autonomic nervous system
controlled by autonomic brainstem nuclei
what controls and innervates breathing muscles
innervated by lower motor neurons of somatic nervous system
controlled by brainstem autonomic nuclei, cerebral cortex, and somatic nervous system
how are the rate and depth of breathing altered
either through reflexes in the brainstem or controlled by the cerebral cortex
define the respiratory center
autonomic nuclei in the brainstem that coordinate breathing
clusters of neurons in the pons and medulla oblongata which control rate and depth of breathing
define the ventral respiratory group (VRG)
generates breathing rhythm and is an integrative center
has four main nuclei: botzinger, pre-botzinger, nucleus retro-ambiguous, and nucleus ambiguous
define botzingner complex
a part of the ventral respiratory group
controls expiration by sending expiratory signals
define pre-botzinger complex
a part of the ventral respiratory group
acts as pacemaker neurons
sets eupnea to roughly 12-16 breaths per minute
define nucleus retro-ambiguous
a part of the ventral respiratory group
inspiratory and expiratory functions
controls mainly inspiratory signals
define nucleus ambiguous
a part of the ventral respiratory group
posterior to other nuclei groups
controls some inspiratory process by controlling things like the uvula and pharynx muscles
define the dorsal respiratory group (DRG)
main nuclei is nucleus of tractus solitarius (NTS)
receives peripheral signals from different receptors
sends signals to inspiration muscles
what are the two pontine respiratory centers
pneumotaxic center and apneustic center
define pneumotaxic center (parabrachial nucleus)
part of the pontine respiratory center
upper aspect of pons
smooths out transition between inspiration and expiration
fine tunes respiratory rate and depth
define apneustic center
part of the pontine respiratory center
lower aspect of pons
controls prolonged inspiration
how are breathing rate and depth determined
how long respiratory center is active
depth determined by how actively respiratory center stimulates respiratory muscles
explain how quiet breathing occurs
begins when inspiratory neurons in the prebotinger complex of VRG fire to excite skeletal muscle causing them to contract which draws air in
explain how the phrenic nerve works with the respiratory center
stems from VRG and DRG come together in the spinal cord
1 nerve comes out each at C3-C5 and come together to form the phrenic nerve which innervates the diaphragm
explain how the intercostal nerves work with the respiratory center
stems from VRG and DRG come together in the spinal cord
1 nerve comes out each at T1-T11 and each go to intercostal and abdominal muscles
what are the three chemical factors that influence breathing rate and depth
central chemoreceptors
peripheral chemoreceptors
muscle chemoreceptors
define chemoreceptors and their function
chemical receptors that monitor concentrations of H+, PCO2 and PO2
how do chemoreceptors work to control breathing rate and depth
chemoreceptors in medulla oblongata bring info to DRG which then talks to VRG
VRG triggers response
what causes ventilation increase which is detected by chemoreceptors
increase in H+ of CSF
increase in blood H+ or PCO2
what causes ventilation decrease which is detected by chemoreceptors
decrease in H+ or PCO2
what do central chemoreceptors in medulla do
monitor pH (H+) changes of CSF
what do peripheral chemoreceptors in aortic and carotid bodies do
monitor changes in CO2, H+, and O2 in the blood
carotid bodies send signals to glossopharyngeal nerve
aortic bodies send signals to vagus nerve
both end up at the respiratory center
what is the major stimulus affecting breathing
blood CO2 levels
why does declining PO2 levels only have a slight effect on ventilation
we have a huge reservoir of oxygen bound to hemoglobin
must drop below 60mmHg to become major stimulus for breathing
explain how muscle chemoreceptors influence breathing rate and depth
skeletal muscles are sensitive to changes in H+ (pH) and K+ concentrations
decreased pH or increased K+ stimulates increase of breathing
explain how muscle and joint proprioceptors influence breathing rate and depth
include internal receptors for mechanical stimuli; detect movement
signals have to go to spinal cord first
ex. muscle spindles, Golgi tendon organs, and joint pressure receptors
explain how irritant receptors influence breathing rate and depth
when you have something in your airway, irritant receptors communicate with respiratory centers through the vagus nerve
causes decrease of airflow in and things like coughing to get irritant out
explain how baroreceptors influence breathing rate and depth
found in pleura and smooth muscle of bronchioles
respond to stretch
hering-breuer reflex - prevents over inflation of lungs
turns on at >800 mL
what does the hypothalamus do
increases ventilation is body is warm
decreases ventilation if body is cold
what does the limbic system do
alters breathing rate due to things like pain and anxiety
what does the frontal lobe (motor cortex) do
controls voluntary changes in breathing patterns
