Ventilation Control

Question 1

types of neurons in VRG

Answer 1

inspiratory and expiratory, project to phrenic, intercostal and abdominal motor neurons

contains pre botzinger complex

Question 2

fn of pre botzinger complex

Answer 2

origin of normal breathing rhythm, output in roots of hypoglossal nerve

Question 3

types of neurons in DRG

Answer 3

mainly inspiratory and sensory

sensory from peripheral receptors

Question 4

location and fn of pneumotaxic and apneustic centers

Answer 4

in pons, PRG

ap- causes gasping, prolonged inspiration

penumo-promotes rhythmic breathing

Question 5

3 major effectors of respiration

Answer 5

phrenic nerve to diaphragm

thoracic motor neurons to intercostals

lumbar motor neurons to abdominals

Question 6

locaiton of peripheral chemoreceptors

Answer 6

common carotid body and in the aortic arch

Question 7

stimulus and mechanism of transmission for carotid body

Answer 7

low O2, transmitted to brain via nerve IX glossopharyngeal

Question 8

describe anatomy of carotid body

Answer 8

very vascular, glomus cell surrounded by sustentacular cells (glia) and smooth muscle

autonomic efferents and CN IX afferents

Question 9

contrast peripheral and central chemoreceptors

Answer 9

peripheral= O2 sensors

central (medulla)= CO2 and H+

Question 10

why is CSF around the brain responsive to CO2

Answer 10

BBB is permeable to CO2 but not ions, susceptible to swings in CO2

low protein content decreases buffering capacity, more responsive to pH change

Question 11

contrast ventilation response to high CO2 to low O2

Answer 11

high CO2 - more gradual increase in ventilation and decrease as normal conditions return- from slower equilibriation of CSF pH

low O2- rapid increase in ventilation, pause of apnea to allow for recalibration on return to normal conditions

Question 12

location and role of pulm stretch receptors

Answer 12

airway smooth muscle, afferent via vagus

inhibit ventilation to protect from overinflation (hering breuer reflex) when stretched

slow adapting- fire the whole length of stimulus

Question 13

result of severing vagus on respiration

Answer 13

cuts off pulm stretch receptor inhibition, increased tidal volume

Question 14

where and what are pulm irritant receptors

Answer 14

b/w airway epithelial cells- rapidly adapting receptors (desensitize even while stimulus remains) that respond to gases, smoke, dust, cold air

Question 15

innervation and function of pulm irritant receptors

Answer 15

afferent via vagus

increase ventilation, bronchoconstriction, coughing

histamine stim in asthma

Question 16

where are J receptors and what to they respond to

Answer 16

Juxta capillary receptors

external wall of pulm capillaries, respond to blood borne stuff, pulm congestion or edema

Question 17

innervation and effect of J receptors

Answer 17

via non myelinated vagus

causes apena followed by rapid shallow breathing, bronchoconstriction, mucus secretion

involved w/ dyspnea w/ heart failure and ILD

Question 18

what causes the uncomfortable feeling that stimulates ventilation w/ held breath

Answer 18

altered proprioception- input from mechanoreceptors

Question 19

describe change in ventilation when both O2 and CO2 are changed

Answer 19

ventilation will be increased more if the other gas is abnormal: ie high CO2 will induce a stronger response to low O2 and vice versa

Question 20

describe changes in ventilation, blood gases and pH during exercise

Answer 20

ventilation increases dramatically but NOT from changes in blood gas or pH- thought to be from cortex or muscle signalling

gases and pH stay flat until anaerobic conditions are met, metabolic acidosis occurs which stimulates more dramatic ventilation change to compensate