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22 spring: Physiology > exam 2 lecture 22 > Flashcards

exam 2 lecture 22 Flashcards

1
Q

The goal of respiration: maintain sufficient ____ with minimal energy

A

ventilation

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2
Q

central processor controls ___

A

•Pattern generator of breathing depth / amplitude

Rhythm generator for breathing rate (periodicity

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3
Q

three types of sensors to control ventilation

A

chemoreceptors

baroreceptors

stretch receptors

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4
Q

where is the central controller?

A

pon

most in the medulla

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5
Q

what innervates accessory respiratory muscles?

A

ventral respiratory group

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6
Q

what innervates the diaphragm and external intercostal muscles?

A

dorsal respiratory group

by the phrenic nerve

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7
Q

respiratory control is a ___ feedback system

A

neagtive

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8
Q

what is the hering breuer reflex and what disproves this theory?

A

taking a breathe triggers a stretch receptor in smooth muscle that triggers another breathe

lung transplant patients disproves this

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9
Q

•Inspiratory impulses are ___ and are dynamic

A

dominate

neurons needed to inhale

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10
Q

during sleep, central drive is ____ so peripheral chemoreceptors stimulate based on O2 and CO2 levels

A

reduced

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11
Q

why are expiratory neurons not as important

A

exhale is passive

neurons only needed for forced exhale

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12
Q

what happens when you cut below the DRG?

A

breathing stops

phrenic nerve comes off the DRG - no dorsal respiratory group= no breathing

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13
Q

what happens if you cut off the pons?

A

breathing with very sharp amplitude

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14
Q

what happens if you cut off the PRG but keep the apneustic center?

A

breathing more normal

still high amplitude and slightly slower but more steady

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15
Q

if you cut above the PRG what happens to breathing?

A

normal breathing

locked in syndrome

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16
Q

what is the most important principal initiator of breathing?

A

dorsal respiratory group

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17
Q

what part of the DRG receives afferent fibers?

A

nucleus tractus solaris

•Nucleus tractus solaris is where afferent fibers of the glossopharyngeal and vagus nerves project, carrying information received about PO2, PCO2, and pH from the carotid and aortic arterial chemoreceptors

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18
Q

•Nucleus tractus solaris is where ___ fibers of the glossopharyngeal and vagus nerves project, carrying information received about ___ from the carotid and aortic arterial chemoreceptors.

A

afferent

PO2, PCO2, and pH

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19
Q

the DRG has outputs via the ___ to the diaphragm, therefor controlling the most important respiratory muscle

A

phrenic nerve

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20
Q

what is the most important respiratory group and why?

A

the dorsal respiratory group (DRG) is responsible for

1) driving the diaphragm
2) receiving/ integrating input from peripheral chemoreceptors.

Therefor it is the MOST IMPORTANT RESPIRATORY GROUP

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21
Q

what does the ventral respiratory group do?

A
  • Connected primarily to vagus nerve
  • “patency of airway”
  • Expiratory neurons
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22
Q

the VRG contains what two specialized groups

A
  • Botzinger complex: inhibit inspiratory cells in the DRG
  • Pre-Botzinger complex: hypothesized (but not proven) to be the precise location of the respiratory rhythm generator
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23
Q

•Botzinger complex:

A

•Botzinger complex: inhibit inspiratory cells in the DRG

found in the ventral respiratory group

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24
Q

•Pre-Botzinger complex

A

•Pre-Botzinger complex: hypothesized (but not proven) to be the precise location of the respiratory rhythm generator

found in the ventral respiratory group

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25
Q

what are the two groups found in the pons that control breathing

A

apneustic center

pontine respiratory group

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26
Q

apneustic center

A
  • Apneustic center - nucleus of the pons
  • Coordinates speed of inhalation and exhalation
  • Sends stimulatory impulses to the inspiratory area – activates and prolongs inhalation (long, deep breaths)
  • Site of the “inspiratory cutoff switch”
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27
Q

Site of the “inspiratory cutoff switch”

A

apneustic center in the pons

28
Q

___ coordinates speed of inhalation and exhalation

A

apneustic center of the pons

this is why when you cut this area off, very sharp very long breaths

29
Q

___ sends stimulatory impulses to the inspiratory area – activates and prolongs inhalation (long, deep breaths)

A

apneustic center of the pons

30
Q

Pontine respiratory group

A
  • Formerly known as the pneumotaxic center
  • Coordinate speed of inhalation and exhalation
  • Sends inhibitory impulses to the inspiratory area•Involved in fine tuning respiration rate
31
Q

___ Coordinate speed of inhalation and exhalation

A

pontine respiratory group in the pons

32
Q

___ sends inhibitory impulses to the inspiratory area of the DRG

A

pontine respiratory group of the pons

33
Q

___ involved in fine tuning respiration rate

A

pontine respiratory group of the pons

34
Q

•Cheyne-Stokes respiration

A
  • Alternating episodes of apnea and crescendo-decrescendo hypernea
  • Caused by damage to respiratory centers in the brainstem, hypoxia
35
Q

___ •Alternating episodes of apnea and crescendo-decrescendo hypernea

A

•Cheyne-Stokes respiration

36
Q

•Apneustic breathing

A
  • Prolonged inspiration due to interruption of the pneumotaxic center (pontine respiratory group of the pons)
  • i.e. “dying gasps”- most likely in the pons
37
Q

•Biot’s breathing

A
  • Normal breathing interrupted by sudden apnea
  • Damage to the pons
38
Q
  • Normal breathing interrupted by sudden apnea
  • Damage to the pons
A

biot’s breathing

39
Q

•Kussmaul’s breathing

A
  • Hyperventilation with hypocapnia caused by acidosis (diabetic)
  • Brain is normal, caused entirely by chemoreceptors
40
Q
  • Hyperventilation with hypocapnia caused by acidosis (diabetic)
  • Brain is normal, caused entirely by chemoreceptors
A

•Kussmaul’s breathing

41
Q
A
42
Q
A
43
Q
A
44
Q

•Respiratory center is in the brainstem (medulla ___)

A

oblongata

45
Q

what are two regions of the brain that affect respiration

A

•Cortex•Conscious control of breath•E.g., holding your breath

•Limbic system and hypothalamus•Emotional states•Panic attack

46
Q

how does the body measure changes in CO2

A

CO2 can diffuse across blood brain barrier combines with H20 and forms H and HCO3-

this will decrease the pH of the CSF (make more acidic)

this change in pH can be detected by H+ receptors

47
Q

•Protons (H+) pass poorly through the ___ but CO2 passes easily

A

blood brain barrier

•Blood pH is therefor transmitted via CO2 to CSF

48
Q

adapt to elevated CO2 levels (reduced pH) by transfer of ___ into CSF (slow). this will stimulate ___

A

HCO3- or Cl-

•Stimulation of this system causes the urge to breath (increase ventilation, get rid of that CO2)

49
Q

•Recent studies suggest additional chemoreceptors throughout the brainstem:NTS, ___

A

locus coeruleus

50
Q

where is all O2 sensing done to control breathing

A

carotid and aortic bodies (peripheral chemosensors)

51
Q

•Afferent nerves (glossopharyngeal for carotid body, vagus for aortic body) run back to the ___ in the medulla to then change the breathing patterns

A

respiratory center (DRG)

52
Q

true or false

aortic bodies exert greater influence than carotid bodies

A

false

•Carotid bodies exert greater influence than do aortic bodies

53
Q

___ receptors are more important in short-term, transient responses than in normal ventilatory control

A

carotid body and aortic bodies

peripheral chemosensors

54
Q

how do O2 sensors work

A

•Glomus cells (type I cells)

  • K channel with O2 sensor
  • O2 opens channel and hyperpolarizes cell
  • Drop in O2 causes reduction in K current and depolarization
  • Resulting Ca2+ influx triggers dopamine release
  • Dopamine initiates action potential in sensory nerve to send the signal back up to the medula•

Glomus cells are derived from the neural crest•

Glomus cells may also be the primary CO2 / pH chemosensor, but isn’t certain

Supported by type II cells (sustentacular cells)

55
Q

how does low O2 effect glomus cells

A

causes K channels to close, which causes depolarization and dopamine to be released causing an action potential

56
Q

what enzyme helps glomus cells to detect oxygen

A

CSE (cystathione gamma-lyase )

•hypoxia decreases CO production•Less CO means less inhibition of CSE•More active CSE means more H2S•More H2S depolarizes cells causing neurotransmitter release

57
Q

what do cigarette help at high altitude

A
  • PO2 must drop to 60 mm Hg (~10,000 ft elevation) before this triggers a change in the glomus cells
  • At these high elevations, PCO2 is also lower, so fails to increase respiratory drive (stimulates person to breathe)
58
Q

___ are much less important than arterial chemoreceptors for ventilation

A

arterial baroreceptors

59
Q

•Bronchiolar smooth muscle is enriched in __ adrenergic receptors

A

β2

60
Q

•____ (sympathetic) lead to bronchodilation

A

Catecholamines

61
Q

•Parasympathetic stimulation of the muscarinic M3 receptors (via ___) causes bronchoconstriction

A

acetylcholine

62
Q

catecholamines cause ___ and acetylcholine causes ___

A

•bronchodilation (sympathetic innervation)

bronchoconstriction (parasympathetic innervation)

63
Q

what is triggered in an asthma attack to cause bronchoconstriction?

A

muscarinic M3 receptors (via acetylcholine- parasympathetic innervation)

64
Q

•J-receptors

A
  • Sense interstitial fluid changes (pulmonary edema)
  • Cause sense of breathlessness
  • Located in capillary walls

breathlessness

65
Q

what is the dominant respiratory driver?

A

CO2

22 spring: Physiology (34 decks)

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