Lecture 5: Control Breathing Flashcards
what are the 3 elements that control the respiratory system? What are their functions?
- sensors that gather info
- central controller in the brain that coordinates info and sends impulses
- effectors (respiratory muscles) receive impulses and affect ventilation
what structures are the sensors of the respiratory system?
chemoreceptors and other other lung receptors
what brain structures are the central control of breathing?
pons, medulla and other parts
what are the pontine respiratory structures (in the pons)
pneumotaxic area and the apneustic area
what are the medullary respiratory structures?
- pre-botzinger complex
- ventral respiratory group
- dorsal respiratory group
diaphragm and intercostal muscles require ____ to inititate inspirations
stimulation by motor nerves
the destruction of motor nerves feeding the inspiratory muscles would lead to ___
paralysis of respiratory muscles and death
give an example of a disease that causes damage to nerves feeding the respiratory muscles
poliomyelitits
the diaphragm is innervated by the ___ nerve
phrenic
what brain structure sends signals to muscles of inspiration to contract?
DRG
the AP sent by the DRG lasts for ___
2 sec
the pre-botzinger complex is also known as the ____generating complex becasue it has ____ cells that set the ___ of normal breathing
rhythm; pacemaker; rhythm
where does the input to pacemaker cells likely come from?
DRG
the pacemaker cells in the VRG likely drive the rate at which DRG inspiratory neurons ___
fire AP
the lower VRG contains fibers that fire during ___
forceful inspiration and expiration
medullary inspiratory neurons receive input from the areas in the pons, which act to ___
fine-tune the output and may stop inspiration
the pneumotaxic area is located in the ___ pons
superior
the apneustic area is located in the ___ pons
inferior
the pneumotaxic area modulates activity of the ___ area
apneustic
the _____ area sends inhibitory signals to the DRG to terminate inspiration
PA
when the PA is activated, the breathing rate is more __
rapid
____ is involved in smoothing the transition between inspiration and expiratiion
PA
t/f the normal rhythm of breathing can exist without the PA
true
the ____ sends stimulatory stimuli to the DRG to prolong inspiration
AA
when the AA is active the rate of respiration ___
slows
t/f the AA is typically overridden by the PA
true
t/f the significance of the AA in adult humans is unclear as its loss poses no significant issues in this group
true
what is apneustic breathing? what is the breathing rate per minute? What is this style of breathing associated with?
prolonged inspiration and short expiration; 1.5 bpm; head injury
chemoreceptors are sensory receptors that respond to changes in what chemicals?
O2, CO2, H+
central chemoreceptors are located on the __
ventral surface of the medulla
____ chemoreceptors are important for minute to minute control of breathing
central
central chemoreceptors respond to changes in ____ and indirectly to changes in ___
pH of CSF; Pco2 in the artery
why do central chemoreceptors respond indirectly to changes in arterial PCO2?
because the CO2 crosses the BBB and eneters the CSF where it is converted to HCO3- and H+
peripheral chemioreceptors are located in the ___ and ___
aortic arch (aortic bodies) and bifurcation of the common carotid arteries (carotid bodies)
the chemoreceptors in the carotid test the blood before it enters the ___
brain
peripheral chemoreceptors trigger increased ventillation in response to ____, ___, or __
decreased Po2, increased Pco2, or increased protons in arterial blood
t/f we can tolerate changes in o2 much better than changes in co2
true
voluntary control of breathing can be achieved by descending pathways from the ___ to the __
cerebral cortex to the respiratory muscle motor neurons
can voluntary breathing be maintained in the presence of involuntary stimulus such as increased co2?
no, its impossible
input from the ___ and ___ can stimulate the respiratory system, allowing emotional stimuli to affect respiration
hypothalamus and limbic system
physical or chemical stimuli can trigger ___ in the upper airways to trigger a cough or sneezing
irritant receptors
what is the diving reflex?
cold water stimulates nasal or facial receptors to stop breathing to protect against aspiration of water
what are 4 influences on respiration?
- voluntary conrtrol
- emotional state
- irriation of airways
- diving reflex
what is hypoxia?
dificiency of oxygen at the tissue level
what are the 4 classes of hypoxia?
- hypoxic hypoxia
- anemic hypoxia
- ischemic hypoxia
- histotoxic hypoxia
what is hypoxic hypoxia and an example of it?
aterial PO2 is reduced, ex: at high altitude or with airway obstruction
what is anemic hypoxia and an example of it?
total blood O2 is reduced due to low RBC, low or abnormal Hb, or CO competition; ex: CO poisoning and anemia
what is ischemic hypoxia and an example of it?
blood flow to tissues is too low to provide enough o2 ; ex: due to obstruction of bv
what is histotoxic hypoxia and an example of it?
quantity of O2 reaching tissues is normal, but cell is unable to use it due to interference with cells metabolic apparatus EX: cyanide poisoning
