Respiratory System Flashcards

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1
Q

The medullary respiratory center

A
  • generates the rhythm for quiet/regular, conscious breathing
  • composed of 2 collections of neurons (dorsal and ventral respiratory groups)
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2
Q

The pontine respiratory group

A
  • is within the pons
  • modifies the rhythm set by the medullary
  • smooths out transitions between inhale and exhale
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3
Q

The most important factors influencing breathing rate and depth are

A

Levels of CO2, O2, and H in the arterial blood (sensed by chemoreceptors)

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4
Q

Central chemoreceptors are located

A

throughout brainstem (including medulla)

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5
Q

Peripheral chemoreceptors are located

A

in aortic arch & carotid sinus (like baroreceptors for BP)

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6
Q

The main trigger for regulation of breathing is

A

Arterial blood CO2 pressure

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7
Q

Hypercapnia occurs when

A
  • Blood CO2 pressure increases causing CO2 to accumulate in the brain, leading to increased acidity
  • ventilation increases to flush out excess CO2
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8
Q

Hypocapnia occurs when

A
  • Blood CO2 pressure is too low
  • respiration is inhibited and slows
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9
Q

Hyperventilation is

A

An increased depth & rate of breathing that exceeds body’s need to remove CO2
- this leads to a decrease in blood CO2 levels (hypocapnia)

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10
Q

Indirect effect on ventilation of peripheral chemoreceptors being sensitive to arterial O2 pressure:

A

Low O2 pressure enhances peripheral chemoreceptors sensitivity to CO2 pressure

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11
Q

Direct effect on ventilation of peripheral chemoreceptors being sensitive to arterial O2 pressure:

A

Substantial drop in arterial O2 pressure is necessary to increase ventilation directly
- Due to the large reserves of O2 carried on Hb

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12
Q

Changes in arterial blood pH can modify respiration via

A

peripheral chemoreceptors
- H does not cross the blood brain barrier

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13
Q

↑ blood H + may be in response to

A
  • ↑ blood CO2 pressure
  • Metabolites causing acidification of the blood (lactic acid, ketone bodies)
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14
Q

The Hypothalamus & limbic system

A
  • Signals respiratory centers to modify respiratory
    rate & depth
  • is in response to strong emotions & pain (i.e gasping in pain)
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15
Q

The Cerebral cortex

A
  • Can exert conscious control over ventilation
    behavior
  • Bypasses the medullary centers & directly
    stimulates respiratory muscles (i.e holding your breath)
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16
Q

Pulmonary irritant reflexes

A
  • Respond to inhaled irritants in nasal passages or
    trachea
  • Cause reflexive bronchoconstriction in respiratory airways
17
Q

Inflation (Hering-Breuer) reflex

A
  • is activated by stretch receptors in visceral pleurae
    & conducting airways
  • Protects lungs from overexpansion by inhibiting
    inspiration
18
Q

Hyperapnea is

A

increased ventilation in response to metabolic needs
- occurs during vigorous exercise to ensure that tissue O2 demands are met
- Unlike hyperventilation, does not cause large
changes in blood CO2 pressure

19
Q

3 neural factors that contribute to change in respiration:

A
  • Psychological stimuli (anticipation of exercise)
  • Simultaneous cortical motor stimulation of
    skeletal muscles & respiratory centers
  • Excitatory impulses to the respiratory areas from
    proprioceptors in muscles, tendons, & joints
20
Q

Atmospheric pressure and O2 pressure are

A

Lower at high elevations

21
Q

Acute mountain sickness (AMS)

A
  • May result from a rapid transition from sea level to altitudes above 8000 feet
  • symptoms are headaches, shortness of breath, nausea, dizziness
22
Q

long-term change from sea level to high altitudes results in acclimatization of the body via

A

◦ Increase in ventilation rate
◦ Lower than normal Hb saturation
◦ Increased production of erythropoietin