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What nerve is the major motor nerve of the larynx?
Recurrent laryngeal nerve
There are 2 major nerves that innervate the larynx.  what are they?
Superior Laryngeal Nerve
  • Interanal (sensory)
  • External (crycothyroid mus.)
  • Recurrent (motor)
Vagus Nerve: motor and senory
List the cartilages from first to last as pass the ETT in:
  • Epiglottis
  • thyroid
  • Cuneiform
  • Corniculate
  • Aretynoids
  • Cricoid
What nerve supplies sensory innervation to laryngeal mucosa below the vocal cords?
Recurrent laryngeal nerve
What nere supplies sendory innervation to the larynx above and including the vocal cords?
Internal branch of the superior laryngeal nerve
List the 3 single cartilages of the larynx

List the 3 paired

What laryngeal muscles abduct the vocal cords
Posterior CricoArytenoids
"Pull the Cords Apart"
Which laryngeal muscles do not get motor innervation from the recurrent laryngeal nerve?
Crycothyroids: innervated by the External brach of the superior laryngeal nerve
What laryngeal muscles relax/shorten the vocal cords?
What do the Lateral crycoarytenoid muscles do?
Adduct the vocal cords
If there is damage to the External branch of the surperior laryngeal nerve,  what are the symptoms and what laryngeal muscle will be paralyzed?
Crycothyroid muscle (only muscle that is innervated by external sup. laryngeal nerve)
S/S: weak, husky voice
this muscle tenses the vocal cords
What is the most common injury after subtotal thyroidectomy?
Unilateral recurrent laryngeal nerve damage
Pt just has a subtotal thyroidectomy and htey are experiencing aphonia?  what is the problema dn what should be done?
Bilateral recurrent laryngeal nerve damage.  the voacl cords are paralyzed--the cords are stuck in an intermediate postition and they can flop together duringinspiration causing airway obstruction
Intubation is required
If airway obstruction occurs after subtotal thyroidectomy, what are 2 possible causes?
Bilateral Recurrent laryngeal nerve damage
on the oxyhemoglobin dissociation curve, what is P50 and what is the normal P50 value?
P50 is the partail presure of oxygen at the which the hemoglobin is 50% saturated by oxygen
*Normal P50= 26-27 mm Hg
If the P02 is 40, what is the O2 sat and what type of blood is it?
PO2 40 = O2 sat 70%
Mixed venous blood
If the PO2 is 60mmHg, what is the O2 sat and what type of blood is it?
PO2 60 = 90% O2 sat
Arterial blood
How many molecules of Oxygen can hemoglobin bind?
4 molecules
If there is a left shift if the oxyhemoglobin  curve, what happens to the P50?
the P50 decreases
Fetal Hbg
All cause a _____ shift in the oxhemoglobin dissociation curve?
Left is LOCKED

the Hgb holds onto the Oxygen (has a greater affinity for it)
What is the Bohr effect?
refers to the shift in the oxyhemoglobin curve in response to an increase or decrease in PCO2
List some factors that cause a right shift of the oxyhemoglobin curve
Rightward shift
ncreased PCO2
Increased 2, 3DPG
Hydrogen ions
Sickle cell

if the P50 is > 27, what way has the oxyhemoglobin curve shifted
When the blood travels through the capillaries of the pulmonary system, what way does the oxyhemoglobin curve shift?
It shifts to the Left to facilitate the loading of O2 into the blood (for a given PO2, the blood holds more O2 when the curve shift to the left)
When there is a rightward shift in the oxyhemoglobin curve, the amount fo O2 carried by hemoglobin is _______
Reduced (the unloading of O2 is facilitated)
HOw do you calculate the amount of dissolved oxygen in the blood?
dissolved oxygen = 0.003 x PO2 = ___ ml O2/100 ml blood at 37 degrees C
Whose law permits the amount of dissolved oxygen in blood to be calculated?
Henry's Law:
Dissolved gas in a liquid = Pgas x Solubility
*solubility depends on Temperature
Calculate the increase in dissolved oxygen in the arterial blood if PaO2 increases form 50 mmHg to 300 mmHg
Dissolved O2 = .003 x 50 = .15
dissolved O2 = .003 x 300 = .90
Increase = .90 -.15 = .75 ml O2/100 ml blood
How do you calculate the total O2 in the blood?
Total O2 = Hgb-bound O2 + Dissolved O2
How do you calculate the amount of Hbg-bound O2 in the blood?
Each fully saturated gram of Hgb carries 1.34 ml of O2
Normal concnetration of Hgb is 15 ml/100ml bl
O2-Hgb = 1.34 x 15 x O2sat (ie .90)
If the SvO2 is 70%, how much oxygen is dissolved in the venous blood?
SvO2 = PO2 40 mmHG
O2 dissolved = .003 x 40 = 0.12 ml O2/100 ml blood
Oxygen is carried in ht eblood in 2 forms.  what are they?
  • hemoglobin bound
  • dissolved
What is the maximum O2 carrying capacity of arterial blood in a young, healthy adult?
20.4 ml
0.3 ml dissolved O2
20.1 ml Hgb bound O2 (assuming 100% sat)
-(1.34 x 15 x 1.0 = 20.1)
Normal, healthy arterial blood has how much O2 dissolved?
0.3 ml O2 dissolved
PO2 = 100, so 100 x .003 = 0.3 ml O2/100 ml blood
If a pt has a normal PaO2 breathing atmospheric air (PaO2 =100), what kind of a change will breathing 100% O2 bring?
the change will be a very minimal b.c the pt's Hgb is mostly saturated already
Who responds better to Oxygen therapy:
pts with poor perfusion in relation to ventilation (deadspace)
pt with poor ventialtion in relation to perfusion (shunts)
pt with deadspace respond better to O2 therapy b/c their Hgb is not fully saturated, so givng more O2 increases the )2 bound to Hgb
on the oxyhemoglobin dissociation curve, hypoxia is defines as_____
PO2 < 60 mmHg
this point begins the steep portion o the curve; on the steep portion, a small decreased in PO2 will cause a large quantity of O2 to be released from Hgb
Maternal Hgb cause a _____ shift in the oxyhemogodin dissocitation curve
Right shift
Approximately 90% of the CO2 transported in the blood is in the form of ______
HCO3; bicarb
What is the Haldane effect?
Describes how a change in PO2 in blood effects the CO2 dissociation curve
  • Decrease in PO2 = the curve shifts up and tot he left (facilitating the loading of CO2)
  • Increase in PO2 = the curve shifts down and to the right (facilitating the unloading of CO2)
The pts PO2 increases from 100 to 500 mm Hg, the amount of dissolved oxygen in the arterial blood increased by how much?
.003 x 100= .3
.003 x 500=1.5
1.5 - .3 = 1.2 ml/100 ml blood
CO2 is transported in the blood in 3 main forms many.  what are they?
  • Dissolved (in RBC or plasma)
  • As Bicarb
  • Chemically bound (to plasma protiens & Hgb)
When the tissues produce CO2, what happens to it?
The CO2 dissuses down a concnetration gradient (Fick's Law) in to the RBC.
CO2 reacts with H2O (in the presense of Carbonic anyhydrase) to form carbonic acid.  This then dissociates to HCO3 and H+.
The HCO3 diffuses down a concnetration gradient out of the RBC (chloride goes in to maintain eltroneutrality)
What is the Hamburger shift?
The chloride shift
this is when CL diffuses into the RBC in exchange for HCO3 diffusing out to maintain nuetrality
How do you calculate the amount of CO2 dissolved int he blood?
0.067 x PCO2
What enzyme is needed for H2O and CO2 to combine and make carbonic acid?
Carbonic Anhydrase
Carbonic acid then dissociates to HCO3 and H+
What chemical drives respiration?
There are 2 respiratory control centers located in the pons (part of the brainstem).  What are they?
PnC: Pneumotaxic Center
ApC: Apneustic Center
both are secondary Respiratory Centers
control Rate and Depth of Inspiration
What group of Neurons in the brainstem control the diaphragm?
DRG:Dorsal Respiratory Group
-Inspiratory Pacemaker, Vital Center
-located in the medulla
Send signals via the Phrenic nerve (A alpha: Big, fast) to the Diaphragm
Send signals to the External intercostal muscles
What nerve carries sensory information from the lung stretch receptors
What refelx is this?
Vagus nerve carries afferent (sensory information)
Hering Breuer Reflex: inhibits inspiration when tidal volume exceeds 1.5 liters
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