l3 Flashcards
What does the rhythm generator in the medulla contain
inspiratory and expiratory group of neurons
what modifies the signals from the medulla
Pneumotaxis centre in the pons
what causes respiratory depression
Opiates/narcotics
Cerebral diseases
where does chemo sensing occur (afferent nerves)
Carotid-(arch-bundle of cells outside bifurcation of carotid arteries) and aortic bodies
what do peripheral chemoreceptors respond to and how
Hypoxia-increase in H+ and CO2
Response- increase ventilation only when PaO2 drops significantly
where and what and how-central chemoreceptors
Hind brain
Sense PaO2 andH+ indirectly through CSF plasma CO2 sensing
Efferent nerves- inspiratory muscles innervation
Diaphragm-phrenic nerves c3-5
External intercostal muscles- thoracic nerves t1-11
Accessory muscles in neck- Sternocleidomastoid- (XI cranial nerve & scalene muscles C3-8 )
where are expiratory muscles located (2)
Abdominal wall
External intercostal muscles
what do lung stretch receptors sense and via which nerve (3)
Vagal nerve
Lung stretch during breathing to terminate breath preventing overstretching
Sense abnormal changes in airway mechanical properties
what are particulate receptors
C-fibre neurons: activated by oedema & endogenous sensitizers= brady kinin
what are irritant receptors
Respond to punctate mechanical stimuli
what are steps 1 & 2 approach t ABG interpretation
1-examine PH PCO2 & HCO3-for academia and alkalemia
2- Determine primary process
What is abnormal ranges where alkalemia and academia are diagnosed
PH: <7.38
PH:>7.42
Primary processes of each acidosis and alkalosis
Respiratory PCo2>44
Metabolic HCO3<22
Alkalosis= resp:low PCO2<36
Met: High HCO3- >26
what is step 3 of ABG interpretation
Calculate anion gap
what is metabolic acidosis
addition of acid or loss of bicarbonate
what constitutes as an anion gap
when additions of acid is called anion gap metabolic acidosis and if anion gap is greater than 12
Main causes for metabolic anion gap acidosis
Glycols, oxopraone L-and D- lactate, methanol aspirin renal failure and ketoacidosis GOLD MARK
Non-anion gap -metabolic acidosis: what is renal tubular acidosis
RTA_ Urinary loss of bicarbonate and hyperchloremic acidosis
what is type 1 RTA:
in distal duct-inability to secrete H+ into lumen
type 2 RTA
type 3
proximal duct - same as Type 1
Comb of features-rare
Base excess
measure of metabolic disturbance- dose of acid required o return blood to normal PH-7. 4- under standard conds-37 degrees< and PCO2 of 40 mmHg
Base deficit is dose of alkali……………
what is step 4 of ABG
Compensatory for acid-base disturbances-needs to be identified
Primary disturbances
Slower: Respiratory acidosis- response-Retain HCO3 respiratory alkalosis- Reduce HCO3 Quicker Metabolic acidosis- Reduce CO2 Metabolic alkalosis- retain CO2
