PSL301: Respiratory 5 Flashcards Preview

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Flashcards in PSL301: Respiratory 5 Deck (110):
1

Ondine's curse is also known as...

congenital central hypoventilation syndrome

2

what is Ondine's curse?

breathe normally during the day, but can't breathe at night (attached to ventilator)

3

What controls respiratory muscles?

spinal motor neurons

4

What controls the diaphragm

Phrenic motoneurons / phrenic nerve

5

Where are phrenic motoneurons found?

cervical spinal cord segments C3, C4, C5

6

phrenic nerve is made up of...

phrenic motoneuron axons

7

What controls the intercostal muscles?

motoneurons for intercostal nerves

8

where are the motoneurons for intercostal nerves found?

Thoracic spinal cord segments T1 to T12

9

List the segments of the spinal cord from top to bottom

cervical
thoracic
lumber
sacral

10

the rhythmic activity of respiratory motor neurons are mainly controlled by...

premotor neurons in the medulla

11

What is the relationship between inspiration/expiration and phrenic nerve activity?

- rapid positive feedback loop for phrenic nerves (more and more active neurons)
- this increasing activity leads to inspiration
- activity suddenly stops = expiration
- no nerve activity during expiration

12

Why is there no phrenic nerve activity during expiration?

expiration is a passive process under normal conditions

13

DRG

dorsal respiratory group

14

VRG

ventral respiratory group

15

NTS

nucleus tractus solitarius

16

PRG

pontine respiratory group

17

Higher brain centers that control breathing connects to... (and where is it located?)

limbic system --> PRG in the pons

18

How does higher brain centers influence breathing?

sending axons to the different reasons in the medulla (which then sends motor neurons to the respiratory muscles)

19

Where is DRG located?

in the NTS

20

PRG sends info to the...

- NTS
- VRG

21

NTS sends info to the...

- inspiratory muscles
- PRG (feedback)

22

NTS is located in the...

medulla

23

What is located on the NTS?

medullary chmoreceptors

24

NTS houses...

DRG

25

VRG sends info to the...

expiratory, inspiratory, pharynx, larynx, tongue muscles

26

NTS receives input from...

sensory input from CN IX, X
- mechanical & chemosensory information about stretch of the lungs

27

What 2 things in the NTS and VRG sends info to each other?

DRG pre-Botzinger complex

28

respiratory neurons display

mutual inhibition (inspiratory inhibits expiratory and vice versa)

29

Which neurons are fired during inspiration?

- I INC
- I DEC
- I CON

30

Which neurons are fired during expiration?

- E INC
- E DEC

31

What does the I INC mean?

During inspiration, neuron firing rate increases

32

What does I CON mean?

During inspiration, neuron firing rate is constant

33

What does E DEC mean?

During expiration, neuron firing rate decreases

34

____ produces respiratory rhythm

rhythm generating neurons in the pre-Botzinger complex

35

where are the pattern generating neurons mainly located?

VRG

36

____ controls the pattern of activation in the pre-motor neurons

pattern generating neurons

37

What does rhythm generating neurons do?

produces respiratory rhythm (pacemaker activity)

38

Where are rhythm generating neurons located?

pre-Botzinger complex

39

What does pattern generating neurons do?

controls the pattern of activation in the pre-motor neurons

40

Function: afferent relay neurons

- integrate peripheral afferent inputs
- distribute info to rhythm and pattern generating neurons

41

Where are afferent relay neurons mostly located?

DRG

42

Function: cranial motoneruons

activate muscles of airway & bronchiolar smooth muscle

43

Location: cranial motoneurons

nucleus ambiguus (part of VRG)

44

muscles of the airway include...

- larynx
- pharynx

45

Function: pre-motor neurons

activate respiratory motoneurons in the spinal cord

46

What are the respiratory motoneurons?

- phrenic
- intercostal

47

Where are pre-motor neurons located?

VRG
DRG

48

respiratory neurons in the pons receive sensory info from...

DRG

49

What does respiratory neurons influence?

initiation & termination of inspiration

50

function: pontine respiratory group

provide tonic input to medulla --> coordinate smooth respiratory rhythm

51

What happens during forced breathing?

- some neurons in medulla becomes activated
- activation of accessory muscles for inspiration
- activation of internal intercostals & abs for expiration

52

example of accessory muscle activated during forced breathing

sternocleidomastoids

53

example of when forced breathing occurs

exercise

54

Respiratory generating neurons can...

1) function as network that oscillates: connected together synaptically
2) be pacemaker cells
3) both

55

What happens during initial phase of hypoxia?

- augmentation of breathing rate
- sigh

56

What happens during late phase of hypoxia?

- depression of breathing rate
- gasping

57

Difference of respiratory pattern in whole animal vs. medulla slice as observed from the pre-Botzinger complex

medulla slice is...
- fictive eupnea
- fictive sigh
- fictive gasping

58

rhythmic breathing is controlled by...

medulla & pons

59

rhythmic breathing can be affected by

- voluntary control from motor cortex
- chemoreceptors
- reflexes
- posture
- startling events
- emotions
- exercise
- pain

60

reflexes that affect breathing

sneezing, coughing

61

how does posture affect breathing?

affects intercostal & abdominal muscles

62

does pain increase or decrease breathing?

increase

63

Which 2 factors that affect rhythmic breathing goes through reticular formation?

- emotions --> limbic system
- sensory stimuli (pain, startling events)

64

3 efferent motor pathways of breathing. Which are the main pathways?

1) brainstem --> spinal phrenic motoneurons --> phrenic nerve --> diaphragm
2) primary motor cortex --> spinal phrenic motoneurons --> phrenic nerve --> diaphragm
3) premotor cortex --> spinal phrenic motoneurons --> phrenic nerve --> diaphragm

(1) and (2) are main

65

peripheral chemoreceptors are affected by...

pO2 and [H+]
- more sensitive when there is low O2
- respond to high H+

66

receptors in the respiratory system

- central chemoreceptors
- peripheral chemoreceptors
- airway & lung receptors

67

location: central chemoreceptors

medulla

68

location: peripheral chemoreceptors

carotid artery & aorta

69

central chemoreceptors are affected by...

[H+]
- respond to high H+

70

peripheral chemoreceptors send signals via the ___ nerve to ____

glossopharyngeal nerve

medullary respiratory neurons

71

airway & lung receptors send signals via the ___ nerve to ____

vagus

medullary respiratory neurons

72

central chemoreceptors send info to...

medullary respiratory neurons

73

medullary respiratory neurons sends signals to the upper airway muscles via the ___ nerve

vagus

74

medullary respiratory neurons send signals to...

- spinal respiratory motoneurons
- upper airway muscles
- airway smooth muscle

75

pathway from medullary respiratory neurons to pulmonary ventilation

1. medullary respiratory neurons
2. spinal respiratory motoneruons
3. respiratory muscles
4. pulmonary ventilation

76

feedback of respiratory muscles

1. muscle receptors
2. spinal respiratory motoneurons

77

pO2 and [H+] levels are affected by...

pulmonary ventilation

78

airway & lung receptors receive signals from...

pulmonary ventilation

79

what are the types of airway & lung receptors?

- stretch receptors (mechanoreceptors)
- irritant receptors (C-fiber endings)

80

stretched out lungs signal...

the end of inspiration

81

stretch receptors are composed of...

- slow adapting receptors
- rapidly adapting receptors

82

irritant receptors responds to...

some irritant in the airway

83

location: stretch receptors

trachea to bronchioles

84

stretch receptors send signals via the ...

vagus nerve

85

Hering–Breuer reflex

reflex triggered to prevent over-inflation of the lungs

86

stretch receptors activate the ____ reflex

Hering-Breuer

87

How does the stretch receptors activate the Hering-Breuer reflex?

stretch receptors present in the smooth muscle of the airways respond to excessive stretching of the lung during large inspirations --> send signal to medulla --> inhibits inspiration signals

88

the Hering-Breuer reflex is more common in...

animals

89

main function of stretch receptors in humans

1) control breathing pattern (TV & rate)
2) dyspnoea

90

define: dyspnoea

- breathing discomfort
- difference between what the control system wants and what is actually achieved
- chemoreceptor signals wanted
- stretch receptor signals achieved

91

location: irritant receptors

throughout the airway

92

irritant receptors trigger...

- breathing & bronchioconstriction
- several reflexes

93

what are the reflexes initiated by irritant receptors?

- sneeze
- aspiration
- cough
- sighs

94

which receptor causes the sneeze reflex?

nasal

95

which receptor causes the aspiration reflex?

epipharyngeal

96

which receptor causes the cough reflex?

- laryngeal
- tracheal

97

which receptor causes the sigh reflex?

- juxtapulmonary capillary (J-receptors)

98

which nerve sends the sneeze signal to the medulla?

trigeminal nerve

99

which nerve sends the aspiration signal to the medulla?

glossopharyngeal

100

which nerve sends the cough signal to the medulla?

vagus

101

which nerve sends the sigh signal to the medulla?

vagus

102

What causes congenital central hypoventilation syndrome?

PHOXb2 gene: codes for TF that doesn't work as well as normal one

103

what is found in mutant genotype for congenital central hypoventilation syndrome

increased number of Ala

104

Function of Phoxb2

needed for development of autonomic neurons

105

people with congenital central hypoventilation syndrome have problems with...

- breathing when sleeping
- ANS

106

What happens in congenital central hypoventilation syndrome?

- alveolar hypoventilation during sleep & wake
- bad respiratory control
- less / no response to hypercabia & hypoxemia
- ANS dysregulation

107

Where is PHOX2B gene expressed?

- pFRG parafacial respiratory group (pFRG)
- retrotrapezoid nucleus (RTN)

108

In addition for the site of PHOX2B action, pFRG and RTN are the site of...

- have central chemoreceptors
- receives info from peripheral chemoreceptors

109

what is used as a treatment for congenital central hypoventilation syndrome?

Phrenic nerve pacemaker

110

what does the phrenic nerve pacemaker do?

stimulate phrenic nerve to bypass all the happenings in the brain

signal causes diaphragm to contract