Week 8

Question 1

central chemoreceptors

Answer 1

Very sensitive to pH (CO2 crosses blood brain barrier easily and converts to H+), located in ECF of brain (medulla)
most influential
respond to pH and PCO2 NOT O2

Question 2

Peripheral chemoreceptors

Answer 2

located in carotid and aortic bodies, respond faster but less powerful than central. Respond to PO2 in addition to PCO2 and pH

Question 3

Lung Receptors (pulmonary stretch)

Answer 3

when stretched, they slow down RR (reflex to pause after deep breath)

Question 4

Lung Receptors (irritant receptors)

Answer 4

respond to noxious gases, dust, smoke etc (cough)

Question 5

Lung receptors (Juxtacapillary J Receptors)

Answer 5

respond to increased interstitial fluid (if capillaries are engorged with fluid) send signal to breathe faster

Question 6

Other Receptors (irritants in nose, pharynx, larynx, trachea)

Answer 6

similar to irritants in lung

Question 7

Other Receptors (joint/muscle receptors in limbs)

Answer 7

stimulate ventilation during exercise

Question 8

Other Receptors (Gamma system)

Answer 8

muscle spindles sense how long muscle is and tells how much to contract

Question 9

Upper airway dilating muscles

Answer 9

nasal alas: dilates nasal passages
genioglosus: protrudes tongue
elevator and tensor palatine: elevate/stabilize soft palate
posterior cricoarytenoid muscle: open laryngeal aperture

contracture dilates air passage

Question 10

C1-C7 come out where

Answer 10

above corresponding vertebral body

Question 11

Innervation of diaphragm

Answer 11

C345

Question 12

Innervation of accessory muscles

Answer 12

C1-C8

Question 13

Innervation of intercostal musscles

Answer 13

corresponding nerve root

Question 14

Innervation of abdominal muscles

Answer 14

T7 and below

Question 15

Phrenic nerve runs between

Answer 15

subclavian artery and vein

Question 16

Spinal cord injury at T7

Answer 16

lose abdominal muscles, less strong expiration

Question 17

spinal cord injury at T6

Answer 17

lose abs, and intercostals-still breathe in but expiration is always passive, never forceful

Question 18

spinal cord injury at T2

Answer 18

everything lost, entirely dependent on ventilator

Question 19

Respiratory centers

Answer 19

pons and medulla

Question 20

Cerebral cortex in respiration

Answer 20

can override function of brainstem within limits

can hold breath, take large breath, hyperventilate

Question 21

limbic system and hypothalamus

Answer 21

emotions, pain, temperature all affect breathign

Question 22

Ventilatory control system, conflicting signals

Answer 22

At high altitudes, low PaO2, sensed by peripheral chemoreceptors-send signals to respiratory centers to increase breathing and PO2. As consequence, PCO2 decreases (alkalosis). Now central control gets two signals-to breathe more to increase PO2 and to breathe less to decrease pH

Question 23

synergy between hypoxia and hypercarbia

Answer 23

in setting of high PCO2, a small amount of hypoxemia (decrease in PO2) causes a larger increase in ventilation

Question 24

Dyspnea and restricted thoracic cage

Answer 24

hyperkyphosis: increased elastic load (decreased compliance), get feedback from stretch, gamma, chemoR, lower tidal volume for same decrease in Pip. likely to develop pneumonia

Question 25

dyspnea and obstructive lung disease

Answer 25

Not a problem of elastane/compliance but rather increased resistance. increased physiologic dead space anxiety--hyperinflation hyperinflation puts diaphragm at mechanical disadvantage

Question 26

hyperventilation

Answer 26

an increase in ventilation that is excessive for rate of metabolic carbon dioxide production, resulting in decreased PCO2

Question 27

Causes of hyperventilation

Answer 27

hypoxemia, anxiety, fever, metabolic acidosis, CHF, aspirin, progesterone, pregnancy

Question 28

Cheyne Stokes

Answer 28

cyclic breathing marked by gradual increase in rapidity, followed by gradual decrease and total cessation

Question 29

Loop gain

Answer 29

corrective response/disturbance. smaller is better

Question 30

Contributors to loop gain

Answer 30

``` circulatory time (time it takes from blood to get from the thorax to the chemoreceptors) neurologic disease ```

Question 31

unstable breathing at sleep onset: CO2-apnea threshold

Answer 31

1. stimulating effect of wakefulness, disappears 2. threshold to stimulate breathing of PaCO2 increases 3. ventilation stops right before falling asleep (til PaCO2 gets to above new threshold)

Question 32

HF and CSA

Answer 32

1. longer circulatory time 2. stimulation of J receptors (increases apneic threshold --larger diff between wakeuful PCO2 and sleeping PCO2 3. more prone to hypoxia during sleep onset apnea

Question 33

Physiologic changes in sleep

Answer 33

1. increased upper airway resistance (more narrow bc cave in from lack of tone) 2. decreased chemosenstiivty 3. inhibition of skeletal muscles (esp REM)

Question 34

Chemosenstiivy and CO2 in regular sleep

Answer 34

lower ventilation and higher PaCO2 Lowest/highest in REM In REM, PCO2 can increase and barely increases ventilation (because less chemrsensitivity)

Question 35

Central apnea

Answer 35

No rib cage or abdominal activity-no respiratory effort

Question 36

Obstructive apnea

Answer 36

apnea because airway is occluded | Abdomen and RC are trying to breathe (see muscle activity)

Question 37

mixed apnea

Answer 37

start as central and develop obstructive

Question 38

Obstructive apnea and soft tissue

Answer 38

completely collapsed on itself-loss of tone dilating muscles so no air gets through

Question 39

Posterior Oropharynx

Answer 39

most vulnerable region of airway 1. obesity--extraluminal positive pressure 2. mandible further back-less space for airway 3. full abdomen--push up on airways--lose longitudinal traction and decrease airway patency

Question 40

Arousal follows apnea

Answer 40

brief, 3s increase in amplitude/frequency of waves on EEG

Question 41

RF for apnea

Answer 41

obesity, increase size of upper airway soft tissue, recessed mandible, increased neck >18 in, nasal airway obstruction, heredity

Question 42

Obstructive sleep apnea Tx:

Answer 42

CPAP, weight loss, avoid supine, avoid alcohol, dental appliances, uvulopalatopharyngoplasty (carve out excess tissue), tracheostomy

Question 43

CPAP

Answer 43

generating air pressure to sten open airway, very effective