Exam 3: Control Of Respiration Flashcards

1
Q

What is neurogenesis?

A

The growth and development of nervous tissue

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2
Q

neurogenesis of respiratory drive is largely where?

A

The brain medulla but influenced by other areas and some peripheral factors

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3
Q

neurons of the brain send impulses down the spinal cord to where?

A

Lower motor neurons which innervate the muscles

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4
Q

What consists of neuron “pools” mostly in the
upper medulla oblongata, with some additional neurons in the
pons?

A

Respiratory control center

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5
Q

What neuronal grouping receives information from chemoreceptors, baroreceptors and lung stretch receptors?

A

Dorsal respiratory group

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6
Q

Where do afferent/sensory signals from vagus and glossopharyngeal enter the respiratory control center?

A

Dorsal respiratory group

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7
Q

What is the main driver of respiratory control?

A

Dorsal respiratory group

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8
Q

Where is the dorsal respiratory group located?

A

Tractus solitarius

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9
Q

The dorsal respiratory group contains what kind of neurons?

A

Inspiratory neurons

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10
Q

Ventral Respiratory Group contains what kind of neurons?

A

Inspiratory and expiratory

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11
Q

Where is the pneumotaxic center located?

A

In the upper pons, within the nucleus parabrachialis

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12
Q

What neuronal grouping of the respiratory control center is wired into the inspiratory neurons of the ventral and dorsal respiratory groups?

A

Pneumotaxic center

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13
Q

Where is the chemosensitive area located?

A

At the ventral surface of the medulla

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14
Q

Neurons of what respiratory control center grouping are responsive to chemistry of CSF?

A

Chemosensitive are

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15
Q

What neuronal grouping of the respiratory control center is wired into the inspiratory neurons of the dorsal respiratory groups?

A

Chemosensitive area

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16
Q

the many inspiratory neurons of the

dorsal respiratory group display rhythm signals called what?

A

inspiratory ramp signal

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17
Q

The inspiratory neurons of the dorsal respiratory group primarily send signals where?

A

The diaphragm

NOTE: normal, restful breathing almost entirely an inspiratory/diaphragmatic
phenomenon (with expiration a passive recoil process)

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18
Q

An increase in inspiratory ramp signal would result in what?

A

Increased contraction of the diaphragm

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19
Q

the pontine pneumotaxic center inhibits the inspiratory neurons (mostly of dorsal respiratory
group) in order to affect breathing how?

A

limit the depth of breathing

20
Q

Increased pneumotaxic action will results in what?

A

Short inspiration (i.e. rapid breathing)

21
Q

Decreased pneumotaxic action will results in what?

A

Lengthened inspiration as seen in restful breathing

22
Q

The magnitude of the ramp signal can be modified/increased by the action of what medullary neuronal grouping?

A

Ventral respiratory group

23
Q

How does the ventral respiratory group increase ramp signal to make breathing more powerful?

A

It has both inspiratory and expiratory neurons that recruit muscles of the ribcage to assist in inspiration and expiration

24
Q

How does the ventilation cycle get voluntarily overridden by “higher center” of the brain?

A

by way of corticospinal and corticobulbar tracts directly to lower
motor neurons of thoracic musculature, bypassing respiratory control center

25
Q

How does the ventilation cycle get modified by pulmonary stretch (i.e. volume) receptors in the smooth muscle of airway?

A

pulmonary stretch receptors in the airways (smooth muscle)

send signals up the vagi (CN X) into the dorsal respiratory group to decrease activity of inspiratory neurons

26
Q

What is the Hering Breuer reflex?

A

is a reflex triggered to prevent over-inflation of the lung. Pulmonary stretch receptors present in the smooth muscle of the airways respond to excessive stretching of the lung during large inspirations

27
Q

What is the main control input from central and peripheral receptors?

A

central chemoreceptor in the form of the “chemosensitive area”
on the ventral surface of the medulla

28
Q

What is the primary purpose of the central chemoreceptor in the form of the “chemosensitive area”
on the ventral surface of the medulla?

A

to regulate the

amount of O2 and CO2 in the body

29
Q

The chemosensitive area on the ventral surface of the medulla is particularly sensitive to what?

A

H+ (↓ pH, and indirectly to ↑ CO2)

30
Q

Why is the chemosensitive area on the ventral surface of the medulla INDIRECTLY sensitive to carbon dioxide?

A

Because it is sensitive to H+ which is derived from the carbonic acid reaction that converts carbon dioxide and water to carbonic acid and ultimately dissociates to bicarbonate and H+

31
Q

What is tachypnea?

A

Increased ventilation depth and rate

32
Q

What do the central chemoreceptors in the form of the “chemosensitive area”
on the ventral surface of the medulla stimulate?

A

The dorsal respiratory group to increased ventilation rate and depth

33
Q

Why do small changes in the partial pressure of carbon dioxide cause significant changes in pH that affect the neurons of the central chemoreceptors?

A

because there is no hemoglobin or conventional buffers in the CSF to stabilize the acidity

34
Q

What are the three features of the carbon dioxide - ventilation relationship?

A

1) partial pressure of CO2 level dramatically affects
ventilation rate
2) even with high O2 levels, CO2 is the
prime determinant
3) as partial pressure of O2 falls, the reaction to the partial pressure of CO2 is even greater

35
Q

What are the peripheral chemoreceptors?

A

Aortic and carotid bodies

36
Q

What are peripheral chemoreceptors most sensitive to?

A

O2 (much less to H+ and CO2 as seen in central chemoreceptors)

37
Q

The peripheral chemoreceptors in the form of the aortic and carotid bodies (chemoreceptors) sample arterial blood and being firing when?

A

arterial partial pressure of O2 starts falling below 100 mmHg (and dramatically so below ~ 60 mmHg)

38
Q

What do peripheral chemoreceptor in the form of the aortic and carotid bodies stimulate?

A

these sensors stimulate the dorsal respiratory group

39
Q

Stimulation of the dorsal respiratory group by peripheral chemoreceptor in the form of the aortic and carotid
bodies will result in what?

A

Increased ventilation rate and depth

40
Q

What limits the depth of breathing by inhibiting inspiratory neurons?

A

Pneumotaxic center

41
Q

Increased pneumotaxic action results in

A

Short inspiration (rapid breathing)

42
Q

Decreased pneumotaxic action (no inhibition) leads to

A

Lengthened inspiration (restful breathing)

43
Q

Resting inspiratory neurons and increased ramp signal coincide with

A

Phrenic output and contraction of diaphragm and external intercostals

44
Q

Expiratory neurons and DEcreased ramp signal coincide with

A

Contraction of internal intercostal

45
Q

What neurons bypass respiratory control center?

A

Corticospinal and corticobulbar tracts