Exam Ii - Adv Pathophys - Regulation Of Respiration

Front 1

The respiratory center is made up of several groups of neurons located bilaterally in the

Back 1

medulla oblongata and pons of the brain stem

Front 2

The respiratory center is divided into three parts

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1. DRG - dorsal respiratory group - inspiration
2. VRG - ventral respiratory group - expiration
3. Pneumotaxic center - located in pons - controls rate and depth of respiration

Front 3

DRG - dorsal respiratory group extends the length of the

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medulla oblongata

Front 4

DRG - most of its neurons are located in the nucleus of the

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tractus soltarius

Front 5

The tractus soltarius area is the location where the sensory termination of the

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vagus and glossopharyngeal nerves transmit signals into the respiratory center from the peripheral chemoreceptors, baroreceptors, and other lung receptors

Front 6

The DRG controls the

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rhythmicity of respiration

Front 7

How does the DRG control the rhythmicity of respiration

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By ramping up over a period of a couple seconds, then shutting down

Front 8

DRG - the ramping allows for

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diagphragmatic stimulation and allows time for elastic passive lung pressure recoil

Front 9

DRG - ramp up time is shorted during

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heavy breathing or exercise and the expiratory phase is shortened

Front 10

Overstretching of the stretch receptors in the bronchi and bronchioles is called

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Hering-Breuer inflation reflex

Front 11

HB Inflation Reflex
Overstretch results in

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vagal stimulation, which transmits to the DRG switching off the ramp time phase

Front 12

HB Inflation Reflex protects the lungs from

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excessive lung inflation and barotrauma

Front 13

What populations have the HB Inflation Reflex

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kids and babies

Front 14

The pneumatic center is located in the

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pons

Front 15

Primary function of the pneumatic center is to

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control the switch off point of the inspiratory ramp

Front 16

If pneumatic center signal is strong - inspiration lasts for a

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shorter period of time

Front 17

If pneumatic center signal is weak - inspiration lasts for a

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longer period of time

Front 18

If pneumatic center signal can increase rate up to ______ or as low as ______

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30-40BPM, 3-5BPM

Front 19

VRG is located in the

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medulla in the nucleus ambiguous

Front 20

VRG is located near the

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DRGs

Front 21

VRG
If respiratory drive increases, then the

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signals spill over into the VRG area and the VRG is contributory to the DRG

Front 22

VRG
Stimulation may either lead to

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inspiration or expiration

Front 23

VRG
These neurons also provide powerful signals to the

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abdominal muscles to help with exhalation during heavy breathing

Front 24

The ultimate goal of respiration is

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homeostasis of O2, CO2, and pH

Front 25

The respiratory center is sensitive to changes in the

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chemical concentrations

Front 26

Excessive CO2 affects the central respirtatory center and

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increases inspiration and expiration mechanisms

Front 27

Does O2 impact the respiratory center

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no

Front 28

O2 acts on the peripheral chemoreceptors located in

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the carotid and aortic bodies

Front 29

Does CO2 directly stimulate DRG, VRG or pneumatic center

Back 29

no

Front 30

How does CO2 indirectly stimulate DRG, VRG or pneumatic center

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there are chemosensitive neurons located near these centers

Front 31

The area around the DRG, VRG, and pneumatic enter is sensitive to

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changes in PaCO2 and hydrogen ions

Front 32

The area around the DRG, VRG, and pneumatic enter is more sensitive to changes in PaCO2 or hydrogen ions

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hydrogen ions

Front 33

Is the area around the DRG, VRG, and pneumatic center within the blood brain barrier

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no

Front 34

Do hydrogen ions cross the blood brain barrier

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no

Front 35

Does CO2 cross membranes

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yes

Front 36

How does CO2 indirectly stimulate the chemosensitive area

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quickly crosses membrane - combines with H2O to from carbonic acid - then dissociates in bicarb and hydrogen ions
CO2 + H2O --> H2CO3 --> HCO3 + H

Front 37

What stimulates the chemoreceptors

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hydrogen ions

Front 38

Does CO2 impact the respiratory system

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yes - huge impact

Front 39

How long does CO2-driven stimulation of the chemoreceptors last

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just a couple of days

Front 40

How does the body compensate for high hydrogen levels

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the kidney retains more HCO3 that binds the hydrogen

Front 41

For what population does the CO2-driven stimulation of central chemoreceptors disappear after a couple days

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COPD

Front 42

Stimulation of central chemoreceptors leads to an increase in

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minute ventilation

Front 43

Under normal circumstances, hemoglobin has the ability to

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shift affinity right or left to deliver adequate O2 despite ventilation UP TO A POINT

Front 44

Can ventilation impact oxygen concentration

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yes, to some degree

Front 45

What is most affected by ventilation changes

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CO2 concentration

Front 46

What two factors affect CO2 concentration

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TV and RR

Front 47

When tissue lacks O2, the body has what special mechanism for respiratory control

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peripheral chemoreceptors located in the aortic and carotid bodies

Front 48

When PaO2 falls below 70 torr

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the peripheral chemoreceptors are stimulated - signal sent through glossopharyngeal and vagus nerves to DRG

Front 49

The chemoreceptor stimulus is especially important when PaO2 falls between

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30-60 torr

Front 50

Glossopharyngeal nerve is associated with

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carotid body

Front 51

The vagus nerve is associated with

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the aortic body

Front 52

Between 20-60 torr - the oxyhemoglobin dissociation curve

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unloads and loads very quickly

Front 53

At SpO2 of 100% - PaO2 is

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90 torr

Front 54

At SpO2 of 90% - PaO2 is

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60 torr

Front 55

At SpO2 of 60% - PaO2 is

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30 torr

Front 56

At SpO2 of 50% - PaO2 is

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27 torr