Jackson 4 Flashcards

1
Q

Rhythmical breathing is controlled by

A

skeletal muscles

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2
Q

inspiration requires action potentials in

A

motor neurons

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3
Q

expiration due to cessation of

A

motor neuron activity and lung recoil

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4
Q

rhythmic contraction controlled by

A

pacemaker neurons

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5
Q

Role of medulla oblongata and pacemaker cells

Activity of pacemaker neurons can be modulated by…

A

activity of pulmonary stretch receptors
drugs, e.g. barbiturates and opiates/morphine
partial pressures of respiratory gases and [H+]

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6
Q

↓ PO2 —->

A

↑ ventilation rate

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7
Q

↑ PCO2 or [H+] –>

A

↑ ventilation rate

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8
Q

regulation of ventilation rate by respiratory gases and [H+] involves

A

chemoreceptors in two locations

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9
Q

peripheral chemoreceptors are stimulated by

A

↑ [H+] or ↓ PO2

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10
Q

central chemoreceptors are stimulated by

A

↑ [H+] in extracellular fluid in brain

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11
Q

Ventilation rate can be modulated by

A

peripheral chemoreceptors responding to a change in PO2

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12
Q

ventilation rate increases below PO2 of about

A

60 mm Hg

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13
Q

note that at PO2 = 60, Hb is ———-, so ventilation rate begins to increase before blood is depleted of O2

A

90% saturated

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14
Q

Ventilation also can be modulated by

A

peripheral & central chemoreceptors responding to a change in PCO2 and [H+]

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15
Q

ventilation rate is much more sensitive to

A

PCO2 than to PO2

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16
Q

rate increases above PCO2 of about

A

40 mm Hg

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17
Q

central chemoreceptor response to decrease in brain pH is

A

primary regulator

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18
Q

CO2 poisoning symptoms depend on ———- – can lead to death

A

level of toxicity

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19
Q

Ventilation rate can be modified by

A

non-respiratory sources of H+

20
Q

metabolic acidosis, e.g.

A

excess lactic acid

21
Q

metabolic alkalosis, e.g.

A

severe vomiting

22
Q

Note that anemia does not

A

change ventilation

23
Q

, carbon monoxide poisoning does not

A

change ventilation

24
Q

During exercise, alveolar ventilation can increase

A

20 fold, but mechanism underlying the increase is not completely understood.

25
arterial PCO2 ------------- until exercise becomes strenuous; venous PCO2 ----------
typically unchanged increases but no change in arterial values
26
ventilation increases in exact proportion to
CO2 production and with severe exercise, arterial PCO2 actually decreases due to hyperventilation
27
decreased PO2?
as with CO2, venous O2 decreases, but not arterial increase in ventilation is proportional to O2 use
28
increased H+? | requires
intense exercise for this to be a factor due to lactic acid accumulation Conclusion: multiple factors provide input to the respiratory center and contribute to increasing ventilation during exercise
29
Hypoxia =
a deficiency of O2 at the level of the tissues
30
old school - RBC packing or use
recombinant human EPO
31
modern option – use gene therapy to increase
endogenous EPO
32
Can also train at high altitude to stimulate
EPO production in response to low arterial PO2.
33
high altitude training effect: can be accomplished at sea level by
sleeping in a hypobaric atmosphere
34
training at low / normal altitude conditions body to utilize
increased O2 availability
35
Physiological principles in sports | How can physiological principles be applied to increase the
O2 carrying capacity of the blood in order to enhance athletic performance?
36
hypoxic hypoxia or hypoxemia -
decreased arterial PO2
37
anemic hypoxia –
normal arterial PO2; decreased hemoglobin and O2 content of blood
38
ischemic hypoxia–
blood flow to tissues is too low
39
histotoxic hypoxia -
cells unable to utilize O2
40
Hypoxic hypoxia can be caused by a number of conditions
hypoventilation – diffusion impairment – vascular shunt ventilation-perfusion inequality
41
hypoventilation
increases arterial PCO2 diffusion impairment – thickened alveoli-blood interface vascular shunt – blood bypasses alveoli ventilation-perfusion inequality – can occur as a consequence of COPD
42
diffusion impairment –
thickened alveoli-blood interface
43
vascular shunt –
blood bypasses alveoli
44
ventilation-perfusion inequality –
can occur as a consequence of COPD
45
Because Patm decreases as altitude increases, PO2
also decreases (even though O2 still 21%)
46
Immediate responses T
stimulate ventilation – increased dependence on anaerobic glycolysis –
47
Acclimatization to high altitude depends on delayed responses that take days or weeks
increased erythropoiesis which results in polycytothemia; stimulated by erythropoietin (EPO), a hormone from the kidney increased 2,3 DPG synthesis which will shift the Hb-O2 curve to the right increased synthesis of other components of O2 delivery and consumption also change: capillary density – mitochondria – myoglobin -