respiration

Question 1

how does alveoli work?

Answer 1

alveoli surrounded by a network of capillaries > increased SA for exchance of o2 and co2
high SA > better exchange of gas

Question 2

what is the role of the VRG

Answer 2

in medulla
- regulate normal breathing at rest (set rate + rhythm)
- contain inspiratory/expiratory motor neurons

Question 3

describe the basic rhythm of respiration (VRG related)

Answer 3

• inspiratory neuron fire for 2s > project to diaphragm and causes contraction
• expiratory neuron fire for 3s > inhibit inspiratory neurons to allow passive exhalation

Question 4

name the additional players besides VRG and their role

Answer 4

pontine center: regulate output from VRG during activities like talking
can inhibit inspiratory neurons in VRG > shorter cycles to increase respiration rate
DRG in medulla: responsive to chemosensors that detect O2/CO2/H+

Question 5

whats the red blood cell enzyme?

Answer 5

carbonic anhydrase :
CO2 + H2O = H2CO3 = HCO3 + H+
increase in CO2 = increase H+ which decreases pH

Question 6

how does the body detect change in CO2 or H+? name the receptor and location and function

Answer 6

central chemoreceptors: in medulla > detect pH in CSF
peripheral chemR: carotid artery + aorta > detect levels of co2 and o2 and project to DRG and act. of chemoR increase with increase CO2 levels or decrease O2 levels NOTE increased CO2 is the strongest activator (why is pH important?)

Question 7

emphasis. WHEN does chemoreceptors in carotid act.

Answer 7

decreasing O2 level and increasing CO2 level

Question 8

describe oxygen sensing by carotid bodies. name players detail mechanism

Answer 8

chemosensor expresses O2 sensitive K+ ch.
decrease in pO2 > detected by ? and leads to inhibition of K+ ch > depol of cell > activates Ca2+ VG ch > influx ca2+ allows exocytosis of NT to CNS

Question 9

describe CO2 sensing by carotid bodies. name players detail mechanism

Answer 9

increase level of CO2 > increase pH which is then sensed by chemoR and identical mec to O2 sensing

Question 10

how does peripheral chemoR communicate with CNS

Answer 10

decrease O2 or increased CO2 levels increase activity of chemoR > activate DRG > project to VRG > increase rate of breathing > increase CO2 and increase O2

Question 11

what are factors that influence RR

Answer 11

• diabetic ketoacidosis
• vomiting
• mammalian diving reflex
• free diving
• SIDS

Question 12

what is diabetic ketoacidosis how does it effect breathing

Answer 12

complication of uncontrolled T1 diabetes
- hyperglycemia > lipolysis (liver metabolize fatty acid in absence of glucose) > by products = ketones + ketoacids > decrease blood pH > chemosensor increases BR > kussmaul respirations

Question 13

how does vomiting effect breathing

Answer 13

• vomit too much > decrease acid from body > increase pH > decrease BR

Question 14

what is mammalian diving reflex and how does it effect breathing

Answer 14

• elicit by col water to face > stop breathing
• inhibition of VRG to prevent aspiration of water
• stim SNS outflow to vasculature = vasoconstriction > shunting of blood to brain
• slows HR by stimulating PNS outflow to heart = balance ^ BR due to vasocon

Question 15

how does free diving effect breathing

Answer 15

hyperventilation > blackout
hyperventilation increases levels of CO2 then exercise > uptake of O2 into muscles = running out of O2 BUT respiratory center are depressed by decreased CO2 conc in blood THUS no urge to breath > black out

Question 16

how does sids effect breathing

Answer 16

sids may be associated with decreased responsiveness of carotid bodies (might be associated with nicotine acting to attenuate their responsiveness to hypoxia)

Question 17

what other parameters does carotid and aortic bodies monitor

Answer 17

blood flow - decreased blood flow decreases oxygen concentration > ^ BR
temperature - increase temperature > ^ BR