B2- Control Of Breathing Flashcards

1
Q

What is minute ventilation litees per minute

A

5L per min

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2
Q

What is maximum minute ventilation eg in exercise

A

125-175 L per min = ventilatory reserve

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3
Q

What is arterial ph at usuallt unless resp acidosis or alkilosis

A

7.35-7.45

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4
Q

If alveolar p02 is around 159, what is arteiral

A

Around 100 mm hg (40 in tissues)

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5
Q

Ppco2 is lower in arrtial than tissues. Around what

A

35-40 compared to 46 mm hg in tissues

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6
Q

At sea lecel what is toral mmhg bsrometeic oressure

A

760 (around 160 for o2/21%)

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7
Q

What is the p h20 (humidity constant) which redcues the 760mmhg and therefore reduces p02 in alceoli too

A

47 = 713 mmhg instead

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8
Q

If o2 is arounr 21% of baromemetric pressure what is it includin humidity

A

150 vs 159 if not humid air

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9
Q

Since barometric pressure decreases when go ip in altitude whag also decreases

A

P02

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10
Q

When do hb on dissocion curve get to 75% saturation (wuite tolerant of low mmhg)

A

40mmhg (venous blood)

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11
Q

Where does it start to rapidly dissoxate

A

At tissues eg around 50% dissocation when at p02 of 27

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12
Q

Why is saturation at wuite low altitudes good for

A

People living in high altitude as you sont wanr dissocation without pick up

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13
Q

How does co2 affect dissociation

A

Infeeases if it reacts with h20 and then forms h and hco via carbonic anhydrase

H binds hb and causes taut state (deox) instwad of relaxed (bohr effect)

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14
Q

What is the respiratory centre of control

A

Medulla oblongata in brsin stem

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15
Q

What sort of signals do they get (afferent)

A

Chemoreceptor signals, proprioceptors, stretch recetors, irritant

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16
Q

Where are the main chemoreceptors

A

Central. They ste in medulla

17
Q

What are drg neurones (during quiet)

A

Mainly inspiratory. They send signals eg down ohrenic to diaphragm snd then external intercostals too

18
Q

Bow do inputs fet to drg

A

Vagus and IX mainly

19
Q

What are vrg in ONLY sctive resp

A

Both insp and exp neurones eg to pahrynx larynx diaphragm and external intercostals

Then internal and abdomjnals for expiration

20
Q

What does rhe pons do

A

Modify outputs by the medulla

21
Q

What do central mainly snese

22
Q

What can cross from blood freely to csf reaching central chemorecetors

23
Q

What does co2 react with ti form the h and hco (h does this) which allows centrak to respond

A

H20 and carbonic anhydrase reaction

24
Q

What does co2 have to be above to cause central chemo to upreg ventilation

A

40 mm hg (sensitive ti hypercapnia)

25
What cant cross freelyb
H and HCO
26
Which layer of endothelial acts as the bbb shrrounding capillaries
Choroid plexus
27
How does cp allow transport of ions like hco, na and cl across their villi into ventrciles (cerebral ventricles)
Acgive transport. Not free movemrnt
28
Why cant central control resp acidosis and what does detect it
Cant detect ph as well in the blood as well(limited to csf). Peripheral detect co2 to an extent too = stop acidosis
29
Peripehrral detecting o2 are not sensitive. At what o2 legel do they respond
Below 60mmhg
30
What % of respiratory drive do they have for co2/ph eg in acidosis
20%. It is weak stimulating
31
Are rhey essential
No
32
Where are cwrotid bodies and what do they send impulses down
Carotid sinus. Send down ix | Aortic down x
33
What happens at high o2 to peripheral
Switch off and centilation stops for abit till ph lwoers and central can respond
34
How do type1 glomus cells in carotid body respond
Detect low o2 and causes k channels to close. This causes depolarisation and ca floods in. Ca flooding causes dopamine release down ix