3. Respiratory Physiology I Flashcards

1
Q

Pulmonary anatomy

Conducting passages – getting the air to where exchange occurs

– Nasal cavity: filters, warms, moistens ____
– Pharynx:oral and nasal cavity meet, ____
– Larynx: ____
– Epiglottis: flap over ____ when swallow

Covered in mucus, ____ to keep damaging agents away
Some structures enclosed in ____ to ensure open during negative pressure. Muscle keeps open smaller tubes.

A
air
mouth breathing
voice box
trachea
cilia
cartilage
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2
Q

Pulmonary anatomy

Respiratory structures: where gas exchange occurs

Respiratory Structures:
•Bronchioles: ____
•Alveolar sacs: clusters of alveoli
•Alveoli – increase ____ for exchange (200 micrometers in diameter)

Respiratory Structures:
Maximized for ____
Closely accompanied by ____
____ in bronchioles to control diameter

* This is where gas exchnage occurs!
* 1/5 of a cm is an alveoli
* Surrounded by capillaries - optimized exchange between air and blood
A

terminal tubes
surface area

gas exchange
vasculature
smooth muscle

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3
Q

Intrapleural space

The lung floats in the pleural cavity –the lungs are not attached but ____ in the thoracic cavity. ____ lubricates the movement of the lungs in the cavity. The pleural cavity is continuously drained by ____, which cause the pleural cavity to be maintained at a ____.

____: infection of the pleural cavity. Very ____. Often sign of additional ____

* The lungs are not attached to the pleural cavity - they float
* Intrapleural space is filled with fluid which is critical for the physics of the exchange of gases, fluids and air
* Slightly negative pressure
A

“float”
pleural fluid
lymphatics
negative pressure

pleurisy
painful
pathology

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4
Q

Pulmonary ventilation
- Normal breathing

• Inspiration
– \_\_\_\_ of diaphragm
pulls lungs down
– \_\_\_\_ forces air into the increased space of the lungs (\_\_\_\_ Law)
• Expiration – \_\_\_\_
– \_\_\_\_ of lungs, chest
wall
– Air leaves
• In normal passive breathing > contraction of diaphragm > space inside the cavity pulls the lungs down
	○ Via boyle's law > inc in volume, pulls air into the lungs
• Expiration in passive state > relax muscle, springs back to normal space > decreasing volume in cavity > elastic recoil leads to pushing of the air
A
contraction
atmospheric pressure
boyle's
passive
elastic recoil
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5
Q

Boyle’s Law

• Pressure inversely proportional to ____ at constant mass,
temperature
– as volume expands, pressure ____
– As volume shrinks, pressure rises

• Explains why air enters lungs, because air rushes in to
equalize ____. If inhale with passages closed, ____.

• Decrease the volume, pressure will increase
A

volume
decreases
pressure
vacuum

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6
Q

Boyle’s Law in every breath

• Pressure inversely
proportional to ____ at
constant mass, temperature

• Pressure is proportional to 1/V
A

volume

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7
Q

Pulmonary Ventilation – extra muscular help for heavy breathing in exercise

• Additional ____ increase rate and magnitude of air influx. The thoracic rib cage moves upward and outward, increasing the volume of the thoracic cavity

  • Muscles of Inspiration
  • external intercostals: raise ____
  • sternocleidomastoid – up on ____
  • scalleni – lifts ____
  • anterior seratus – lifts other ____
  • Muscles of Expiration
  • ____
  • ____
    • More than just the diaphgram contracting and relaxing
    • Breathing out can be most problematic in certain diseases
A

muscles

rib cage
sternum
1st 2 ribs
ribs

abdominal recti
internal intercostals

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8
Q

Pulmonary pressures: inspiration and expiration

  • ____ changes as breathe in and out
  • ____ changes as breathe in an out – try inhaling when close epiglottis
  • Pleural pressure: pressure of pleural fluid between ____. Constant drainage gives ____, holds lungs in place. Lowest at ____
  • Alveolar pressure: pressure of air in alveoli. ____ at rest. ____ during inspiration, ____ during exhalation
  • Transpulmonary pressure: ____. Elastic forces, r____
  • Changes in all variables most rapid during ____ phases• Breath in:
    ○ Volume in lungs increases, and then you exhale and it decreases
    • Pressure
    ○ Alveolar pressure
    § Pressure starts at ____ because it’s In balance with the outside air (want it to be in equilibrium)
    § Start to breathe in > negative pressure, because the pleural pressure is very negative > increasing the volume creates a vacuum in pleural cavity and tugs on alveolar and opens them up a bit
    § Reach top of inspiration; pleural is at it’s lowest point, but the alveolar pressure ____; when you exhale > ____ > translated into increased pressure in alveolar spaces that slowly goes down
    ○ Transpulmonary pressure
    § Changes in pressure are greatest at the ____, and slow down when you get to the end of inspiration/expiration
    • Why does alveolar pressure rise at end of inspiration?
    ○ Start at vacuum > and now you have more air in your lungs and now pressure is ____ (alveoli is given enough time to equilibrate the pressure)
    • As air leaves you get equilibration in ____ and alveolar pressure
A
volume
pressure
lung and cavity
negative pressure
max lung volume
atmospheric
negative
positive

pleural pressure - alveolar
recoil pressure
early

0
increasing
contraction

beginning
increasing
atmospheric

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9
Q

Pulmonary pressures: Differences in pressures drive airflow

Why do alveolar pressures change? ____

• Atmo pressure before inspiration is same as \_\_\_\_ pressure; and pleural is \_\_\_\_
• As inpsire > increase vacuum > pleural goes down to \_\_\_\_, creates a vacuum instead the alveoli > air rushes in > equlibrates at \_\_\_\_
• Opposite at expiration
	○ Contraction > net increase in pressure in \_\_\_\_ pressure > increase pressure of \_\_\_\_ space > pushes air out
	○ Equilibration of air here and air outside
• Why do alveolar pressures change > air coming in and \_\_\_\_, and the \_\_\_\_ and \_\_\_\_
A

boyle’s law
alveolar pressure
-4

-6
0
pleural
alveolar

equilibrating
muscles
Boyle’s law

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10
Q

Compliance
How much does the volume change for a given increase in ____; balloon vs. soccer ball

Caused by

  1. ____ of lung itself: collagen and elastin.
  2. ____

Need ____ more pressure to increase volume for lung filled with air than fluid. This difference due to ____ forces.
Surface tension is ____ of lung elasticity

• Compliant - amount of forces you need to expand lung and [???]
• Increase the pressure, and the volume of the lung expands quickly
	○ Do not need a big increase in pressure to inflate it
• [???]
	○ Why does it need more pressure to expand on air than just water
• [???]
A

pressure

elastic forces
surface tension

3x
surface tension
2/3

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11
Q

Surface tension

Molecules at edge form ____ bonds, water drop attempts to ____ at surface.

LaPlace’s law
Pressure = 2 x surface tension
radius of alveolus (100 μm)

Need more pressure to inflate alveolus if ____ high, or ____ small, to stop collapse

• Water molecules bonding are happier when it contact with other \_\_\_\_ and not the air
• Sphere shape - bondings try to contract the shape and keep this in a \_\_\_\_ more stable situation
• If alveoli is small > takes more pressure to take it to cause to open up, or it will \_\_\_\_ upon itself
	○ A \_\_\_\_ alveolus is likely to collapse upon itself
	○ The way the body deals > uses \_\_\_\_ along the \_\_\_\_, that disrupts the surface tension; the forces that try to pull the alveoli onto the itself
A

stronger
contract

surface tension
radius

water molecules
thermodynamically
collapse
larger
surfactant
edge
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12
Q

Surface tension in lung

  • In lung, surface tension from fluid coating acts to ____ alveoli
  • Pulmonary surfactant – ____
  • Detergent-like phospholipid breaks up ____ bonding, surface tension.
  • Secreted by ____ cells, released in ____.
  • Produced in ____ trimester, so ____ infants given surfactant
    • Used to be why premature babies died
    • DPPC is secreted by type II alveolar > breaks up the bonding of water molecules and weakens the ____ it tries to get it to collapse upon itself
    • Key steps in neonatal survival > added surfactant to neonatal babies > their lungs would not collapse
A
collapse
DPPC (dipalmitoylphos phatidylcholine)
H2O
type II
lamellar bodies
3rd
premature
force
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13
Q

____ used to measure pulmonary volumes

• Used to get a basic measure of amount air you can ____ into your lungs

A

spirometer

fit

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14
Q

Pulmonary volumes

Tidal volume: VT -____ breath – ____ L
Inspiratory reserve volume: IRV – ____ with full force - ____ L
Expiratory reserve volume: ERV- ____ with full force. ____ L
Residual volume: RV ____ L

Note: Volumes here are for average young male. Females 25% less. Also ____ for smokers.

• Tidal volume
	○ Sitting calmly, diaphragm is contracting and relaxing
• Inspiratory reserve volume
	○ \_\_\_\_ chest wall as much as you can; getting as much air in as possible
	○ 3 L - can put a lot more air in your lungs when you do it \_\_\_\_
• Expiratory reserve volume
	○ Exhale as much volume as possible
• Residual volume
	○ The little bit of air that's always \_\_\_\_ over
A

normal
0.5

inspire
3
expire
1.1

1.2

reduced
expand
actively
left

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15
Q

Pulmonary capacities

Inspirational capacity: IC
IC=____
IC = ____ L
IC = max ____

Functional Residual Capacity: FRC
FRC=____
FRC=____ L
FRC=air in lungs after ____

Vital Capacity: VC 
VC=\_\_\_\_
VC = \_\_\_\_
VC=\_\_\_\_ L
\_\_\_\_ then \_\_\_\_

Total Lung Capacity: TLC TLC=____
TLC=____

* Everything you can inspire is from bottom of tidal to the top of IRV
* Vital capacity - the total range of air you can fit into your lungs
A

VT+IRV
3.5
inspiration

ERV+RV
2.3
normal expiration

IRV + VT + ERV
IC + ERV
4.6
inhale maxillary
exhale maxillary

VC+RV
IC+FRC

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16
Q

Summary - Pulmonary Ventilation

  • Gas exchange occurs in ____, not conducting passages
  • Contraction of diaphragm enough for ____, additional muscles needed for ____
  • Increased pulmonary volume creates ____, pulls air into alveoli
  • Surface tension decreases ____, lessened by ____
  • Pulmonary volumes, capacities quantify air regions• Surface tension makes it more difficult to open up the small alveoli
A

respiratory structures
normal breathing
heavy breathing

negative pressure
compliance
surfactant

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17
Q

Pulmonary circulation

Getting O2 to the blood and removing CO2
Blood passes through pulmonary capillaries in ____ sec normally, ____ sec with increased cardiac output

Note: pulmonary arteries blue because lacking in O2, pulmonary veins red because oxygenated.

Pulmonary arteries wider____, thinner ____ than systemic; more compliant to accommodate stroke volume of ____, dissipate pressure

A

0.8
0.3
bore
walled
right ventricle

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18
Q

Pulmonary blood pressures

• Pulmonary artery pressure like ____ for systole, ____ during diastole. Both less than ____
• Pulmonary pressures (mmHg) S=25, D=8, Mean = 15. Fall
rapidly to ____ mm Hg in pulmonary capillaries (peripheral capillaries ____ mm Hg). Helps ____

• RVC goes up and down during contraction
	○ Ventricular pressure goes down because the muscle is relaxing
• PAC goes down, but not to same extent
	○ Some pressure is \_\_\_\_
• Changes in pressure that occurs in PA with \_\_\_\_
	○ Very rapidly, once to the capillaries you have a steady pressure of \_\_\_\_mmHg
		§ Important for dynamics of exchange of air and fluids
		§ Want changes in pressure eliminated by the time you get to the \_\_\_\_
A

right ventricle
higher
aortic pressure

7
17
gas exchange

kept
distance
7
pulmonary capillaries

19
Q

Hypoxic pulmonary vasoconstriction
Matching blood and air flow

• Key point to get blood to alveoli with most ____
• Normally, pulmonary vessels adjust to increasing PO2 by ____ and to decreasing PO2 by ____.
• Stretching of alveoli releases ____, dilates pulmonary arteries
• If oxygen in alveoli fall below 70% of normal, less ____, adjacent blood vessels ____, increase vascular resistance: hypoxic lung ____.
• Opposite in systemic vessels where low oxygen ____ vessels to increases
flow. ____ in body, ____ in lung.

* Make sure you're getting blood to alveoli with most oxygen; don’t waste blood in areas that don't have a lot of oxygen
* Reduction in stretching > reduction in release of NO > reduction in dilation, resulting in less blood being diverted to the alveoli > increases vascular resistance
* Deposit in body, withdraw in the lungs
A
oxygen
enlarging
contracting
NO
NO
constrict
vasoconstriction

dilates
deposit
withdrawal

20
Q

Dead Space: air that does not reach respiratory structures, no gas exchange

Anatomical dead space: Anywhere that air enters passages but not available for ____
____ more efficient than shallow because less dead space. Dead space expired ____
Breathe

Alveolar dead space :
No blood to ____. ____ situation

• Air enters into the bronchi, but if not in respiratory structures the air isn't available for gas exchange
	○ Breathe in deeply > increasing % of inhaled air that goes into alveoli spaces
	○ Reducing the amount of anatomical dead space
• If taking a shallow breath, the air you exhale comes first from the \_\_\_\_ passages
A

gas exchange
deep breaths
first

alveolus
pathological

conducting

21
Q

Blood only flows when pulmonary capillary pressure > alveolar pressure

Vertical lung – gravity and hydrostatic forces mean pulmonary arterial pressure subject to considerable ____

More blood towards ____ of lung than top

Standing upright creates problems for
____

• The lung was previously horizontal, and it changed shape > created problems for pulmonary blood flow
• [???]
	○ More blood at lower part of lung rather than the top
A

gradient
bottom
pulmonary blood flow

22
Q

Zones of pulmonary blood flow

Blood only flows when
pulmonary capillary pressure > alveolar pressure

Zone 1: blood pressure less than ____ all the time. No ____. Not normal, but occurs if ____ drops e.g. after blood loss

Zone 2: alveolar pressure greater than ____ but less than ____ blood pressure. Blood flows ____

Zone 3, Blood pressure greater than ____ all the time. Blood flows ____

PA = alveolar pressure
Pa = artery pressure
Pv= venous pressure
• Zone 1
	○ \_\_\_\_ of the lung
	○ Blood pressure is less than alveolar pressure always
	○ No blood flow into the apex of the lung
	○ Most people will have no zone 1 in their lungs; this is \_\_\_\_
		§ Will be seen in drop in arterial pressure, where you lost a lot of lung
• Zone 2
	○ Middle portion of lung
	○ Alveolar pressure is greater than diastolic, but less than systolic
		§ Blood flows into the lung sometimes - intermittent
• Zone 3
	○ Bottom of lung
	○ BP > alveolar pressure throughout the entire cycle
		§ Blood flows continuously
A

alveolar pressure
blood flow
arterial pressure

diastolic
systolic
intermittent

alveolar pressure
continuously

apex
abnormal

23
Q

Zones of pulmonary blood flow
Capillaries are ____ by blood pressure and ____ by alveolar air pressure

Zone 1: No blood flow during any part of the cardiac cycle; alveolar pressure > ____. ____
Zone 2: Intermittent blood flow only during ____ peak pressure
Zone 3: Continuous blood flow; ____ always > than alveolar pressure

A

distended
contracted

capillary pressure
RARE
systolic
capillary pressure

24
Q

Pulmonary blood pressure in exercise

Blood flow to lungs increased ____ with heavy exercise because:

  1. Increasing # of ____
  2. Increasing ____ to double ____ through capillaries
  3. Increased ____

Together, moderate rise in pulmonary arterial pressure
• Less ____ on heart
• Prevents ____ in lungs

A
7x
open capillaries
diameter
rate of flow
pulmonary arterial pressure

strain
edema

25
Q

Pulmonary blood flow in exercise

Increase in ____ at lung apex enough to convert from ____

• Look at amnount of blood going into the lung
	○ At rest: most of blood goes towards \_\_\_\_, but a general increase all the way through
• Portions of lung that were previously zone 2 are converted into zone 3 when you're doing a lot of \_\_\_\_
	○ Increases pressure to be greater than the alveolar pressure
A

pulmonary blood pressure
zone 2 into zone 3

bottom
exercise

26
Q

Fluid dynamics in the lungs: Push and Pull

Forces (mmHg)
Out:
\_\_\_\_ 7 
\_\_\_\_ 14 
\_\_\_\_ 8
TOTAL OUTWARD +\_\_\_\_
vs. INWARD
Capillary osmotic = -\_\_\_\_
NET = +\_\_\_\_
So net \_\_\_\_ of fluid to interstitial space

Drains/pumped out lymphatic system
Maintains ____
Keeps fluid from filling ____

A rise in ____ beyond the normal range will result in increased pressure in pulmonary capillaries, resulting in ____

• Multiple presusres that force blood out of capillary
	○ Osmotic pressure pulls fluid out of the \_\_\_\_ (negative)
	○ Interstitial pressure is a vacuum, pulls fluid \_\_\_\_
	○ +29 is the force that drives fluid out of capillaries toward the lung
• To combat that, you have the osmotic pressure that's inside the capillary
	○ Net change is 1 mmHg that \_\_\_\_ fluid out, this increased fluid movement is picked up by \_\_\_\_, drained through, and helps maintain that negative pressure
	○ There's not net leak of fluid into interstitial space bc you have drainage of the lymphatic system
		§ Otherwise it would fill the alveoli with \_\_\_\_
• Rise in \_\_\_\_ beyond range > increased fluid in interstitial space, and eventually into the alveoli
• Very primitive system
• A lot of what is seen with pathology has to do with imbalances of this \_\_\_\_
A

capillary pressure
interstitial osmotic pressure
interstitial fluid pressure
+29

-28
+1
leak

negative pressure
alveoli

left atrial pressure
pulmonary edema

capillary
out

pushes
lymphatics
fluid
left arterial pressure

pressure gradient

27
Q

Pulmonary edema

  • If left atrial pressure increases, pulmonary capillaries pressure ____, interstitial space fills with ____ and alveoli flood
  • If damage to ____ occurs (e.g. via ____, poison gas), proteins & fluid leak into interstitial space and also cause ____ because of change in ____
    • Reduces surface area available for gas exchange
    • [???]
A
increases
fluid
capillary membranes
pneumonia
alveolar edema
osmotic pressure
28
Q

Pulmonary Arterial Hypertension
• ____ of pulmonary blood vessels
• ____ works harder, eventually swells
• ____, more common in ____

• Right heart ventricle has to work harder, and has to increase itself against increased pressure; the \_\_\_\_ is greater
A
constriction
right heart
rare
women
afterload
29
Q

Treat pulmonary arterial hypertension with…. Viagra

  • Nitric oxide dilates pulmonary arteries by increasing ____
  • ____ degrades cGMP
  • Viagra inhibits degradation by ____, increases ____, greater ____ of pulmonary arteries
  • Viagra helps treat ____; PDE5 relatively specific for ____• NO leads to production of cGMP > activates kinases > lowers cxn of Ca++ > leads to a reduction in the contraction/relaxation
    ○ Ca++ involved in cross-bridge interaction in muscle cells
    • More cGMP > reduce the amount of ____ > thereby reducing the ____ > relaxation of muscles > reduce the resistance, and widens up the BV to increase the flow
    • Drug inhibits the breakdown of cGMP
    ○ PDE5 inhibitor
    • Leads to the greater dilation of the pulmonary arteries
    ○ Not very effective
    ○ PDE5 is not widely distributed:
    § In the penis, and the pulmonary vessels (elderly, usually females)
A
cGMP
PDE5
PDE5
cGMP
dilation
pulmonary hypertension
pulmonary vessels

Ca++
contraction

30
Q

Summary: Pulmonary Circulation and Fluid

• Pulmonary circulation to drop off CO2, pick up O2
• Pulmonary pressure like ____ during
systole, less in diastole
• Mean capillary pressure ____ mm Hg, varies with ____
• Blood flow only when ____ > ____, depends on zone
• ____ diverts blood to air
• Drainage of fluid through lymphatics prevents ____
• In exercise, blood flow 7x through ____ and ____

• HPV
	○ Alveoli that are stretched do not release NO > constriction of pulmonary vessels around alveoli
A
right ventricular pressure
7
zone
blood pressure
alveolar pressure
hypoxic pulmonary vasoconstriction
recruitment
dilation
31
Q

Respiratory control in ____:

very primitive because breathing critical

A

medulla and pons

32
Q

Respiratory center – central control

\_\_\_\_ in brain stem – very primitive
\_\_\_\_– inspiration
\_\_\_\_ – both inspiration and expiration
\_\_\_\_ - pacemaker
\_\_\_\_– blocks the switching off of the DRG
A
medulla oblongata and pons
dorsal respiratory group
ventral respiratory group
pre-botzinger center
apneustic center
33
Q

Dorsal respiratory group - inspiration

____ beating rhythm – even when ____
Signal (AP frequency) ramps up for ~____, stops for 3 s (allow ____)
____ better than sudden start (Gasp!)
Termination of ____and ____nerves – input from peripheral chemoreceptors baroreceptors on breathing

• DRG - breathing in
A
endogenous
severed
2
elastic recoil
ramp
vagal
glossopharyngeal
34
Q

Pre-Bötzinger complex – pacemaker

  • pre-Bötzinger complex (preBötC) - neurons in ____
  • Only identified in humans in 2011
  • In May 2018 publication, identified cell types responsible for pacemaker activity in ____ mice using optogenetics
  • Expressed ____ channels in neurons expressing embryonic transcription factor ____ in intact adult mice to interrogate their function.
  • Archaerhodopsin - ____ – slowed or stopped breathing when turn light on (____)
  • Channelrhodopsin - ____ – increased ____ when turn light on (photoinhibition)• Recently recognized in animals, and couldn’t find it in humans in 2011
    • Able to show that the complex is important in the pacemaking signalling
    ○ Took advantage of ion channels that can be gated in response to light > wanted to know if expressed in particular cells
    ○ Expressed 2 types of ion channels in neurons that express [???]
    § Archaerhodopsin - light-dependent - hyperpolarized
    □ ____ breathing when activated
    § Channelrhodopsin - light-dependent - depolarized
    □ Increased in ____, and in the ____ of breathing
    • Using CR to understand how dental pain goes from pulp to trigeminal neuron
A
ventral respiratory center
non-anesthetized
light-sensitive
Dbx1
light dependent hyperpolarization
photoinhibition
light dependent depolarization
rate of breathing

stops
AP
rate

35
Q

Pre-Bötzinger complex – pacemaker

  • pre-Bötzinger complex (preBötC) - neurons in ____
  • Only identified in humans in 2011
  • In May 2018 publication, identified cell types responsible for pacemaker activity in ____ mice using optogenetics
  • Expressed ____ channels in neurons expressing embryonic transcription factor ____ in intact adult mice to interrogate their function.
  • Archaerhodopsin - ____ – slowed or stopped breathing when turn light on (____)
  • Channelrhodopsin - ____ – increased ____ when turn light on (photoinhibition)• Recently recognized in animals, and couldn’t find it in humans in 2011
    • Able to show that the complex is important in the pacemaking signalling
    ○ Took advantage of ion channels that can be gated in response to light > wanted to know if expressed in particular cells
    ○ Expressed 2 types of ion channels in neurons that express [???]
    § Archaerhodopsin - light-dependent - hyperpolarized
    □ ____ breathing when activated
    § Channelrhodopsin - light-dependent - depolarized
    □ Increased in ____, and in the ____ of breathing
    • Using CR to understand how dental pain goes from pulp to trigeminal neuron
A
ventral respiratory center
non-anesthetized
light-sensitive
Dbx1
light dependent hyperpolarization
photoinhibition
light dependent depolarization
rate of breathing

stops
AP
rate

36
Q

Ventral respiratory group - overdrive

Located in \_\_\_\_, \_\_\_\_
Inactive during \_\_\_\_
When increased ventilation is signaled, VRG kicks in to increase \_\_\_\_
Mainly \_\_\_\_, some inspiration
Used as overdrive mechanism during \_\_\_\_
• Inactive during tidal breathing, and when ventilation is increased it becomes activated > increasing ventilation; mainly expiration, some inspiration
A

nucleus ambiguus
nucleus retroambiguus

ventilation
expiration
exercise

37
Q

Chemical control of central respiratory control – CO2 via H+

  • Chemosensitive area in ____, close to ____
  • CO2 in blood crosses Blood Brain Barrier (H+ hydrophilic)
  • Converted to ____, ____ by Carbonic Anhydrase
  • H+ binds to receptors in ____ area near surface
  • Signal to ____ to increase ____• Receptors that respond to H+ ions
    ○ Want to fire when too much ____ in blood
    ○ Cannot get H+ to cross the BBB
    ○ As CO2 builds up, it crosses BBB with water, and converted by carbonic anhydrase into H+ and HCO3-; the H+ bind to chemosensitize area, and leads to increased ventilation
    • ____ feedback system
A
ventral medulla
surface
H+
HCO3-
chemosensitive
doral respiratory group

CO2
subconscious

38
Q

Peripheral chemoreceptors - O2 feedback

  • Mainly in ____ – bifurcations of carotid arteries
  • Blood flow very high so always “____” PO2
  • Drop in PO2 increases ____ – very sensitive below ____ mmHg where Hb saturation drops
  • Signal via ____ nerves to ____ in medulla – increase ____
	• Accurate measure of arterial O2 cxn
	• Very sensitive to changes in the PO2
		○ If increases - drop in firing
		○ If decreases - at 60 mmHg > rapid increase in the firing rate of the carotid body neurons
			§ About where the \_\_\_\_ stops
A
carotid bodies
arterial
firing
60
glossopharyngeal
dorsal respiratory center
inspiration

hemoglobin saturation

39
Q

Hering-Breuer inflation reflex - triggered to prevent lung over-inflation

Stretch receptors in bronchioles activated if tidal volume ____x normal
Signal via ____ nerve to switch off ____
Decreases duration of ____n and thus increases rate of ____
More, ____ breaths

• If bretahe too much > stretchr ector > vagus nerve > inhibt inspiratory center > inhibiting diaphgram contraction via the phrenic nerve
A
3
vagus
inspiration ramp
diaphragm
inspiration
shallower
40
Q

Respiratory center: Anesthesia-induced respiratory depression

Anesthetics act on ____ to reduce ____
____, sodium pentobarbitol can depress breathing at concentrations needed for ____
____ is a significant cause of death, brain damage and malpractice claims in the perioperative period

* Anesthesia has direct effects on respiratory control centers
* [???]
A

respiratory center
ventilation
anesthesia
postoperative opioid-induced respiratory depression

41
Q

Fentanyl reduces ____
Asterisks- artificial ventilation to keep rat alive

Opioids thought to block receptors in ____ - pacemaking center

Also alter sensitivity to changes in ____

Enkephalin inhibits ____ activity, but naloxone augments ____ and the ____

A

respiratory rate
pre-botzinger
chemosensors

carotid body
activity
hypoxic ventilatory response

42
Q

Summary of control of respiration

* Feedback systems put in place to keep us breathing
* \_\_\_\_ in lung, sensitive to changes in \_\_\_\_ > fires on neurons > changes rate of nerve impules to muscles
* Ventilation going into chest wall > affects amount of \_\_\_\_ into lungs > altered by \_\_\_\_ to match level of oxygen and blood
* Hemoglobin and blood buffers > affects levels of \_\_\_\_, O2, \_\_\_\_ > chemoreceptors (central and peripheral ones) > \_\_\_\_ neurons in brainstem to alter the feedbacks
A
mechanoreceptors
volume
blood/air
perfusion
CO2
pH
respiratory
43
Q

Summary: Respiratory Control
• DRG controls ____
• VRG signals both ____ during heavy breathing
• Increased CO2, via ____, increases central chemosensitive area to increase ____
• Decreased O2 activates ____ to increase ____

A
basic inspiratory rhythm
inspiration and expiration
H+
respiration
peripheral chemoreceptors
respiration