Regulation of Respiration Flashcards by Tyler Turner

What are the 5 major respiratory centers

Dorsal Respiratory group (DRG)
Ventral Respiratory group (VRG)
Pontine respiratory group (PRG)
Botzinger complex (BotC)
Pre-botzinger complex

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What are the functions and locations of the medullary respiratory centers? What are they?

These center initiate breathing and are located in the reticular formation of the medulla

Dorsal respiratory group (DRG)
- Located in the nucleus of the tractus solitarius
The Ventral respiratory group (VRG)

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What respiratory center is located in the nucleus of the tracts solitaries

The Dorsal Respiratory Group (DRG)

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What are the two Pontine respiratory centers

(located in the pons)

The Apneustic
The Pneumotaxic center (Pontine respiratory group PRG)

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The brain controls both the ______ of breathing and the ______

frequency, pattern

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The two pontine respiratory centers mainly control

rate and depth of breathing

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explain the inspiratory “ramp” signal

Established by the DRG (Dorsal Respiratory Group) the nervous signal that is transmitted to the inspiratory muscles is not an instantaneous burst of action potentials . Instead, it begins weakly and increases steadily in a ramp manner for about 2 seconds in normal respiration. Then it ceases abruptly for approximately the next 3 seconds, which turns off the excitation of the diaphragm and allows elastic recoil of the lungs and the chest wall to cause expiration.

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The dorsal respiratory group is located in the

dorsal portion of the medulla

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The Dorsal Respiratory group sets _______ of respiration

basic rhythm

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Most of the neurons of the Dorsal respiratory group are in the

nucleus of the tractus solitarius (NTS) and medulla reticular substance

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_____ is the sensory termination of both the vagal and glossopharyngeal nerves

NTS

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NTS receives information from

Peripheral chemoreceptors
Baroreceptors
Several types of receptors in the lungs

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What are the principle initiators of the phrenic nerve activity

Dorsal respiratory group

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Establishes ramp signal

Dorsal respiratory group

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What is the primary function of the PRG (Pneumotaxic center)

Control the switch off point of the inspiratory ramp

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A strong PRG signal results in ____ breaths per minute

30-40

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A weak PRG signal results in _____ breaths per minute

3-5

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Where is the Pneumotaxic center located

in the superior pons

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lesions of the _____ influence respiratory timing

PRG

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Lesion os the PRG result in

loss of the ability to turn off inspiration (without additional input from the vagus nerve)

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Function of Pneumotaxic center

-mainly controls rate and depth of breathing

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The Pneumotaxic center transmits signals to the

inspiratory center (DRG)

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Where is the Apneustic respiratory center located

in the inferior pons

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Loss of function to the apneustic center causes

prolonged inspiratory gasping (apneuses)

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The normal function of the apneustic center may be to

limit lung expansion

______ is the failure to turn off inspiration

Apneusis

Where is the ventral respiratory center located

in the ventrolateral portion of the medulla

Neurons of the ventral respiratory center are found in the

retrofacial nucleus, nucleus ambiguous and nucleus retroambiguous

The postal part of the Ventral respiratory group is the ________ and may be associated with

Botzinger complex, coordinating VRG output

The intermediate part of the VRG is associated with

the dilation of the upper airway during inspiration

Neurons of the caudal region of the VRG synapse with motor neurons to the internal intercostal and other muscles used for

forced expiration

Neurons of the VRG are almost totally inactive during _________

normal quiet respiration

During increased pulmonary ventilation, respiratory signals spill over from the DRG into the VRG, which then contributes to the

increased respiratory drive

The rhetorical nucleus of the VRG contains expiratory neurons which form the ______

botzinger complex

What respiratory center neurons do not participate in the basic rhythmical oscillation that controls respiration

VRG

This is a small area in the rostral part of the VRG

Pre-Botzinger complex

Believed to be the site which generates the timing (frequency) of the respiratory rhythm (central pattern generator)

Pre-Botzinger complex

Deciding the length of _____ and _____ is important to determining frequency of respiratory rhythm

inspiration and expiration.

reflex that is a protective mechanism to prevent excess inflation of the lungs. it begins with stretch receptors in the muscular portions of the walls of the bronchi and bronchioles

Hering-Breuer inflation reflex

The Hering-Breuer inflation reflex pathway

stretch receptors in muscular portions of walls of bronchi and bronchioles ----> dorsal Respiratory group neurons ---> cessation of inspiratory ramp

what is hypercapnia

increase in carbon dioxide levels

What is hypoxia

a decrease in oxygen levels

Hypercapnia and hypoxia lead to ______ activity in most neurons

decreased

Chemoreceptors _____ their rate of activity when hypoxia or hypercapnia occur

increase

What are the two types of chemoreceptors

- Central | - Peripheral

Central chemoreceptors are located

bilaterally 0.2 mm beneath the ventral surface of medulla

Sensitivity of central chemoreceptors

- Sensitive to H+ - H+ does not easily cross the blood-brain barrier - CO2 does easily cross the blood-brain barrier thus they are Indirectly sensitive to carbon dioxide levels in blood (based on pH)

Peripheral chemoreceptors include

- Receptors in the aortic arch | - Carotid body receptors

Peripheral chemoreceptors are sensitive to

concentrations of oxygen (especially), carbon dioxide, and hydrogen ions

Central chemoreceptors heightened sensitivity to increased levels of CO2 last for several hours but then begins to decline due to ____ adjustment to plasma pH

Renal

Heightened sensitivity to CO2 in central nervous system leads to what in the kidneys

kidneys will increase blood bicarbonate levels: - reduces plasma and CSF {H+} - Bicarbonate ions diffuse through the blood-brain barrier

Peripheral receptors are more sensitive to changes in ______ levels in the blood and less sensitive to changes in plasma concentration of ____ and _____

oxygen, carbondioxide and hydrogen ions

Locations of peripheral chemoreceptors

- Aortic arch (aortic bodies) - At the bifurcation of the common carotids (Carotid bodies) - (these are not the same as carotid baroreceptors)

What are the two types of carotid bodies

- Type I (glomus) cells | - Type II (sustentacular cells)

Type I (glomus) Carotid body cells

- chemosensors - PO2 dependent K+ channels result in K+ efflux when PO2 is high, leading to hyper polarization of the cells - decrease in PO2 closes channels and results in a depolarization that opens calcium channels, leading to neurotransmitter release - located close to fenestrated capillaries

Type II (sustentacular) carotid body cells

-play a support role similar to glial cells

Carotid body receptors pathway

decrease pO2 leads to depolarization onto hering nerves-----> CN IX-----> DRG

Aortic bodies pathway

CNX----> DRG

Chemoreceptors are exposed to PO2 of ______ blood not ____ blood

arterial blood not venous blood

___ and ____ are mainly responsible for regulating ventilation (at sea level) for PO2 between 60 and 80 mmHg

PCO2 and H+

where are slow-adapting pulmonary stretch receptors located

within the airways of the lungs

Slow-adapting pulmonary stretch receptors signals travel in the _____ to the ______

vagus nerves, medulla

Signals from slow-adapting stretch receptors actions

- terminate inspiration | - prolong expiration

Are slow-adapting pulmonary stretch receptors important in controlling tidal volume in adults at rest

probably not

slow adapting pulmonary stretch receptors are important in controlling respiration in

infants and adults during exercise

Where are rapidly-adapting pulmonary stretch receptors found

Within the airways of the lungs

Rapidly-adapting pulmonary stretch receptors are sensitive to

irritation, foreign bodies in airway, and stretch

Signals from the rapidly-adapting pulmonary stretch receptors travel in the _____ to the brain

vagus nerve

These stretch receptors override the normal respiratory control mechanisms and elicit cough

Rapidly-adapting pulmonary stretch receptors

Thesauri are sensory endings (C fibers) in the alveolar wall in juxtaposition to pulmonary capillaries

J Receptors

J receptors are sensitive to

Pulmonary edam (i.e. CHF)

Signals from J receptors travel to the brain via the

vagus nerve

stimulation of J receptors elicits

cough | Tachypnea

Does J receptor override the normal respiratory control mechanisms

Yes