S2 Bsf Exam 2: Control Of Breathing

Front 1

Respiration is generated & regulated by the respiratory center in the ________ & _________

Back 1

medulla & pons (brainstem neurons)

Front 2

Respiration is modified by input of information from:

Back 2

-higher brain centers (cortex, hypothalamus, and limbic system)
-systemic receptors (receptors in the lung and chest wall, skeletal muscles and joints, chemoreceptors) (afferent pathway/parsympathetic)

Front 3

The input of information from the medulla reaches the muscles of ventilation via ______________________ conveyed to the diaphragm

Back 3

somatic motor neurons (the phrenic nerves (C3-C5))
(efferent pathway)

Front 4

In the medulla oblongata (medullary), the ___________ respiratory groups regulate inhalation

Back 4

Dorsal

Front 5

In the medulla oblongata (medullary), the __________ respiratory groups regulate BOTH expiration & inhalation

(increase resp. rate & cause active exhalation)

Back 5

Ventral

Front 6

In the pons, the _______________ center STIMULATES the dorsal respiratory group (DRG), thus STIMULATING inspiration

Back 6

apneustic

Front 7

In the pons, the _______________ center INHIBITS the apneustic center, decreases tidal volume & increases respiratory rate

Back 7

pneumotaxic

Front 8

_____ is the most important regulator of ventilation

Back 8

CO2


(rate & depth (tidal volume) used to maintain PaCO2 close to 40 mmHg)

Front 9

Ventilation is increased by: (3 things)

Back 9

High PaCO2
Low PaO2
Low pH

Front 10

The __________ chemoreceptors are in the medulla oblongata & provide a majority of the respiratory control

Back 10

central

Front 11

The _____________ chemoreceptors are in the glomus cells on the aortic & carotid bodies

Back 11

peripheral

Front 12

The central chemoreceptors are sensitive to changes in ________________
& are NOT sensitive to changes in __________________

Back 12

sensitive to CSF [H+]

not sensitive to blood [H+]

Front 13

The central chemoreceptors are directly stimulated by ____________
& indirectly stimulated by ___________

Back 13

directly by increased [H+] in CSF

indirectly (& most strongly) by increased PaCO2

Front 14

The BBB is impermeable to ____ & ______

Back 14

H+ & HCO3- (charged ions)

Front 15

What is the most important distinction between peripheral & central chemoreceptors?

Back 15

Peripheral are sensitive to changes in PaO2
(central are NOT)

Front 16

Peripheral chemoreceptors stimulate ventilation in response to: (3 things)

Back 16

decreased PaO2 (less than 60)
(^only physically dissolved O2)
increased [H+]
increaesed PaCO2

Front 17

Sensory input from the peripheral chemoreceptors is conveyed via ____________________

Back 17

the glossopharyngeal & vagus nerves


(peripheral chemoreceptors also release NTs)

Front 18

The Hering-Breuer reflexes are in place to prevent what?

Back 18

alveolar overdistention or atelectasis (damage to alevoli)

Front 19

What kind of reflexes?
located- upper airway
stimulated- deformation, dust, smoke, etc
afferent signals via- vagus, trigeminal, olfactory n.
stimulation- coughing or sneezing

Back 19

Reflexes from irritant receptors

Front 20

What kind of reflexes?
located- walls of pulmonary microvessels
stimulated- emboli, edema, chemicals (capsaicin)
afferent signals via- vagus n
stimulation- tachypnea

Back 20

Pulmonary J-receptors (juxtapulmonary-capillary receptors)

*responsible for "air hunger" sensation (shortness of breathe)

Front 21

Ventilation increases as ________ increases

These effects are (greater/less) when an individual is awake due to higher reticular formation activity

Back 21

PaCO2

greater

Front 22

Ventilation increases as _____ decreases

Back 22

PaO2


*response mediated through peripheral chemoreceptors in carotid & aortic bodies

Front 23

______________ increases the ventilatory sensitvity to CO2

Back 23

metabolic acidosis

*response to alkalemia is weak

Front 24

Q: Hyperventilation is diagnosed when:

Back 24

PaCO2 < 40 mmHg

Front 25

Q: If a perfect match exists btwn alveolar ventilation & perfusion, then expected responses to increased PACO2 & decreased PAO2 are:

Back 25

airway dilation (bronchiodilation) & pulmonary vasoconstriction

Front 26

Normal Arterial pH

Back 26

7.4

[H+] = 0.00000004 Eq/L

Front 27

Consequences of pH< 7.4 (acidemia)

Back 27

arrhythmias


(caused by anything that adds H+ or removes alkali)

Front 28

Consequences of pH > 7.4 (alkalemia)

Back 28

seizures. vascular collapse



(loss of H+ or addition of alkali)

Front 29

Principal H+ buffers

Back 29

Blood (H2CO3, HHb, HProt)
Interstitial fluid (H2CO3)
Intracellular fluid (HProt, H2PO4-)
Kidney (Phosphate)

^(give up H+ and take it back to buffer)

Front 30

_________ provides instantaneous H+ buffering

Back 30

blood

Front 31

The __________ regulate retention/elimination of CO2 (buffer)

Back 31

Lungs



(minutes-hours)

Front 32

The ______ are the main bicarbonate (HCO3-) buffer system

Back 32

Kidneys (pK= 6.1)

(also do some H+ buffering)

(hours-days)

Front 33

What kind of buffer does bone serve as?

Back 33

exchanges of Ca2+, phosphate, & release of carbonate


(hours-days

Front 34

Describe Ionic shift

Back 34

buffering system that exchanges intracellular K+ for extracellular H+


(2-4 hrs)

Front 35

Henderson-Hasselbach equation

Back 35

pH = pK +log ([HCO3-]/(0.03 * PCO2))

Front 36

Respiratory acidosis is associated w/ ___pH secondary to ___ PaCO2


Due to?

Back 36

decreased pH secondary to increased PaCO2
(hypercapnia--> acidosis)

due to decreased CO2 elimination by lungs (increased dead-space ventilation, hypoventilation)

Front 37

Respiratory alkalosis is associated w/ ____ pH secondary to ____ PaCO2


Due to?

Back 37

increased pH secondary to decreased PaCO2
(hypocapnia--> alkalosis

Increased elimination of CO2 by lungs (hyperventilation)

Front 38

Common causes of respiratory acidosis

Back 38

inadequate alveolar ventilation
over-production of CO2
increased intake of CO2

Front 39

A drop in pH (acidosis) (stimulates/decreases) the rate of alveolar ventilation

Back 39

stimulates



*hyperventilation, PaCO2 < 40 mmHg

Front 40

A rise in pH (alkalosis) (stimulates/decreases) the rate of alveolar ventilation

Back 40

decreases



*hypoventilation, PaCO2 > 40 mmHg

Front 41

Differentiate btwn an "acute", "chronic", or "compensated" respiratory disorder

Back 41

acute= w/o compensation
(low/high pH, normal [HCO3-])

chronic= w/ compensation, but still not at 7.4
(low/high pH & low/high [HCO3-])

compensated= pH value returned to 7.4
(normal pH, low/high [HCO3-])

Front 42

Determine Acid-base disorder & compensation:
1. pH> 7.4
2. [HCO3-] > 24 mEq/L
3. PCO2 > 40 mmHg

Back 42

Metabolic alkaosis
w/ respiratory compensation

(0.7 mmHg increase PCO2 per 1 mEq/L increase in {HCO3-]

Front 43

Determine Acid-base disorder & compensation:
1. pH> 7.4
2. PCO2 < 40 mmHg
3. [HCO3-] < 24 mEq/L

Back 43

Respiratory alkalosis
w/ renal compensation

(5 mEq/L decrease in [HCO3-] per 10 mmHg decrease in PCO2)

Front 44

Determine Acid-base disorder & compensation:
1. pH< 7.4
2. PCO2 > 40 mmHg
3. [HCO3-] > 24 mEq/L

Back 44

Respiratory acidosis
w/ renal compensation

(3.5 mEq/L increase [HCO3-] per 10 mmHg increase in PCO2)

Front 45

Determine Acid-base disorder & compensation:
1. pH< 7.4
2. [HCO3-] < 24 mEq/L
3. PCO2 < 40 mmHg

Back 45

Metabolic acidosis
w/ respiratory compensation

(1.2 mmHg decrease in PCO2 per 1 mEq/L decrease in [HCO3-])

Front 46

Metabolic or respiratory disorder?

pH matches PCO2
(Ex: both acidic, pH higher, PCO2 lower)

Back 46

respiratory acid-base disorder

Front 47

Q: PaCO2 of 53 mmHg & pH of 7.3 indicate what?

Back 47

respiratory acidosis

Front 48

Q: PaCO2 of 52 mmHg (only info) indicates?

Back 48

hypoventilation

Front 49

Q: [HCO3-] is 35 mEq/L (only info) indicates?

Back 49

respiratory acidosis
(renal compensation for respiratory acidosis)