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86 terms

(8) Control of Respiration

STUDY
PLAY
what is the distinct difference between cardiac and respiratory control?
- cardiac doesn't need an external source to function
- respiratory depends on medulla to activate muscles to cause breathing
the 4 types of receptors that influence the inspiratory center are ____
- peripheral chemoreceptors
- central chemoreceptors
- lung stretch receptors
- muscle and joint receptors
the peripheral chemoreceptors are sensitive to ____ (3 things)
O2, CO2, H+
the central chemoreceptors are sensitive to ___
H+
the peripheral chemoreceptors send afferents to the inspiratory center via ______ (2 CN)
- CN IX
- CN X
the lung stretch receptors send afferents to the inspiratory center via ______ (1 CN)
CN X
the apneustic center has a(n) _____ effect on the inspiratory center
excitatory
the pneumotaxic center has a(n) _____ effect on the inspiratory center
inhibitory
the inspiratory activates the diaphragm via the _____
phrenic nerve
the respiratory center is located in the _____
pons
the VRG and the DRG are located in the ___
medulla
the respiratory group inactive during quiet breathing is _____
VRG (because responsible for expiration, which is passive at rest)
the VRG is located dorsally near the root of CN ___
IX
the DRG is a network of neurons that extends in the ventral brain stem from the spinal cord to the ______
pons-medulla junction
the VRG integrates input from the ___ and ____ receptors
- peripheral stretch receptors
- chemoreceptors
the inspiratory center is located in the _____ of neurons in the reticular formation
dorsal respiratory group (DRG)
the inspiratory center (in the DRG) is responsible for ____
rhythm (sets frequency of inspiration)
the expiratory center is located in the _____ of neurons in the reticular formation
ventral respiratory group (VRG)
the expiratory center is responsible for ____
expiration
the _____ contains rhythm generators whose output drives respiration

(is this wrong? its in the picture)
VRG
the ____ integrates peripheral sensory input and modifies the rhythms generated by the other respiratory group

(is this wrong? its in the picture)
DRG
inspiratory depth is determined by how actively the respiratory center ____ the motor neurons serving the respiratory muscles
stimulates
the greater the stimulation by the respiratory center, the ____ the number of motor units excited and force of respiratory muscle contraction
greater
respiratory rate is determined by _______
- how long the inspiratory center is active OR
- how quickly it is switched off
the peripheral chemoreceptors have a _____ effect on the respiratory centers in the medulla and pons
stimulatory
the peripheral chemoreceptors are activated by
- ___ O2
- ___ CO2
- ____ H+
- decreased O2
- increased CO2
- increased H+
the central chemoreceptors have a _____ effect on the respiratory centers in the medulla and pons
stimulatory
the central chemoreceptors are activated by
- ___ CO2
- ____ H+
- increased CO2
- increased H+
TRUE OR FALSE:
central chemoreceptors are sensitive to O2
false
receptors in joints and muscles have a _____ effect on the respiratory centers in the medulla and pons
stimulatory
the irritant receptors in the lungs have a ____ effect on the respiratory centers in the medulla and pons
inhibitory
the stretch receptors in the lungs have a ____ effect on the respiratory centers in the medulla and pons
inhibitory
higher brain centers in the _____ have a +/- effect on the respiratory centers in the medulla and pons because this is where you see ____ control over breathing
voluntary
other receptors (e.g. pain) and emotional stimuli act through the _____ to have a +/- effect on respiratory centers in the medulla and pons
hypothalamus
____ is the most potent and most closely controlled molecule
CO2
normally, arterial PCO2 is ___ mmHg
40
arterial PCO2 is normally maintained within __ mmHg of 40 mmHg
3
arterial PCO2 is normally maintained within 3 mmHg of 40 mmHg by an exquisitely sensitive homeostatic mechanism mediated mainly by the effect that rising CO2 levels have on the _____ of the brain stem
central chemoreceptors
arterial CO2 crosses the BB and ____ equilibrates with CO2 in the CSF
rapidly
H+ and HCO3 cross the BBB ____
slowly
arterial CO2 combined with metabolic CO2 to _____ smooth muscle
dilate
when compared with arterial blood, the pH of CSF is ____ and the PCO2 is ____, with little protein buffering
pH lower, PCO2 higher
increased arterial PCO2 will cause a _____ in the pH of the CSF
decreased
central chemoreceptors in the medulla will respond to ____ in the CSF
H+
(mediates 70% of the CO2 response!)
peripheral chemoreceptors in the carotid and aortic bodies will mediate ___% of the CO2 response
30
the central and peripheral chemoreceptors send afferent impulses to the ____
medullary respiratory centers
the medullary respiratory centers send efferent impulses to the ___ to ____ ventilation
respiratory muscle, increase
increased ventilation will ______ PCO2
decrease
increased ventilation and decreased PCO2 will cause arterial PCO2 and pH to return to ___
normal
in the chemosensory contributions to ventilatory drive, a stimulus of acute hypercapnia will mostly stimulate _____ and have a ____ effect on ventilation
central chemoreceptors; very large increase
in the chemosensory contributions to ventilatory drive, a stimulus of chronic hypercapnia will mostly stimulate _____ and have a ____ effect on ventilation
central chemoreceptors; large increase
in the chemosensory contributions to ventilatory drive, a stimulus of acute mild metabolic acidosis will mostly stimulate _____ and have a ____ effect on ventilation
peripheral arterial chemoreceptors, slight increase
in the chemosensory contributions to ventilatory drive, a stimulus of chronic mild metabolic acidosis will mostly stimulate _____ and have a ____ effect on ventilation
peripheral chemoreceptors, moderate increase
the only way central chemoreceptors will respond to O2 is if ____
O2 is really low
peripheral chemoreceptors are located in the _____
carotid and aortic bodies
peripheral chemoreceptors in the carotid body are innervated by ____
CN IX (pharyngeal branch of glossopharyngeal)
peripheral chemoreceptors in the aortic arch are innervated by ___
CN X (vagus)
_____ receptors are located next to capillaries, and detect fluid build-up
juxtacapillary (J) receptors
there are specialized tissues that sense the local O2 tension in the
- ___ cells of the carotid body
- ____ bodies in the lungs
- _____ cells of the fetal adrenal medulla
- ____ cells of the resistance pulmonary arteries
- fetoplacental ____
- systemic _____
- the ______ in the fetus
- glomus cells of the carotid body
- neuroepithelial bodies in the lungs
- chromaffin cells of the fetal adrenal medulla
- smooth-muscle cells of the resistance pulmonary arteries
- fetoplacental arteries
- systemic arteries
- ductus arteriosus
Specialized tissues that sense the local oxygen tension include glomus cells of the carotid body, neuroepithelial bodies in the lungs, chromaffin cells of the fetal adrenal medulla, and smooth-muscle cells of the resistance pulmonary arteries, fetoplacental arteries, systemic arteries, and the ductus arteriosus. although all tissues are sensitive to severe hypoxia, these specialized tissues respond ____ to moderate changes in O2 tension within the physiologic range (roughly 40-100 mmhg in an adult and 20-40 mmHg in a fetus)
rapidly
In the pulmonary-artery smooth-muscle cell (shown in the upper half of the figure) during normoxia, an outward potassium (K+) current, illustrated by the single channel trace that shows steplike opening and closing, keeps the membrane potential at about -50 mV or -60 mV. This hyperpolarization prevents ___ from entering the cell through the voltage-gated _____ channel
calcium, L-type calcium
____ inhibits potassium-channel activity and depolarizes the membrane to about -20 mV, permitting calcium entry.
Hypoxia
In the ductus smooth-muscle cell (lower half of the figure), by contrast, the outward potassium current is maintained during ___ and is inhibited by ____.
hypoxia, normoxia
A rise in oxygen, as at birth, then causes membrane ____ and calcium entry
depolarization
The chief function of the carotid body is to increase respiration in response to ___-
hypoxia
The proximal pathway in the type 1 cell of the carotid body is similar to that in the pulmonary-artery smooth-muscle cell. Hypoxia ____ potassium-channel activity, shown in the single channel trace, causing membrane depolarization, calcium influx, secretion, and increased action potentials in the carotid-sinus nerve
inhibits
. If the membrane potential (Em) is "clamped" at -60 mV, hypoxia no longer leads to an increase in the cytosolic calcium (Ca2+ i), indicating that the increase in calcium requires membrane _____
depolarization
Cytosolic calcium normally rises sharply as oxygen levels fall below __ mm Hg.
60
Increased calcium stimulates the release of ____, a marker for secretion. pA denotes picoamperes.
dopamine
The specialized tissues in the body that sense oxygen share a common mechanism that involves
- ____ channels
- membrane _____
- ____ calcium channels
- potassium
- potential
- L-type
In vascular smooth-muscle cells, oxygen sensing also involves calcium release from the sarcoplasmic reticulum and calcium entry through store-operated channels, as well as calcium ____
sensitization
Obstructive sleep apnea, defined as the presence of at least FIVE obstructive events (apneas and hypopneas) per hour ____
during sleep
The obstructive sleep apnea-hypopnea syndrome, defined as the presence of at least FIVE obstructive events per hour with associated ____
daytime sleepiness
Obstructive sleep apnea is found in 9 to 26% of middle-aged people without specific risk factors for the disorder, whereas obstructive sleep apnea-hypopnea syndrome is found in ___-___% of the same population
2-4
the biggest symptom of sleep apnea is ___
tiredness during the day (including falling asleep at the wheel)
patients with sleep apnea tend to ___ during sleep
snore
patients with sleep apnea tend to be ______ and ___
overweight and males
how do you diagnose sleep apnea?
sleep study
how do you treat sleep apnea?
CPAP (forces airways open)
in the "clinical features" of sleep apnea, sleep fragmentation leads to daytime ____
hypersomnolence
in the "clinical features" of sleep apnea, sleep fragmentation leads to daytime hypersomnolence, which leads to ____ (3 things)
- alteration in personality
- accidents
- performance decrements
in a sleep study test, 4 things that are monitored are ___
- HR
- impedance
- thermistor,
- SaO2
thermistors measure the ___
air
a lot of air as measured by the thermistor indicates ___
snoring
SaO2 should be _____ normally
flat
in sleep apnea, SaO2 is found to ____
go up and down