Exam I - Lecture 7 Flashcards
during mitral regurgitation, the left ventricle volume in phase 2 should
decrease, as it’s moving back into the atria. (should be isovolumetric contraction)
During mitral regurgitation, which part would have the MOST regurgitating blood flow?
beginning of phase 3, cause that’s the largest difference in delta P (between ventricle and atria) + more pressure in the ventricle with full contraction.
How long does mitral regurgitation last?
From phase 2 all the way to during phase 4.
When is the most backwards blood flow occurring during mitral regurgitation phase 4?
Beginning of phase 4
What is artificially high with mitral regurgitation?
Ejection fraction/stroke volume, because you dont know where the blood is going.
Equation for ejection fraction is
Stroke volume divided by EDV (70/120) = 58.33%
If we have dilated cardiomyopathy with stretched out ventricles, how is our EF adjusted?
lower than normal cause it has a ton of volume in there but its weak and stretched.
What happens to EF with hypertrophy?
Higher because it has less filling and pumps more out of what it has.
With concentric LVH, how are the contractile filaments/sarcomeres built?
Stacked on top of each other.
With eccentric LVH, how are the sarcomeres built?
Built in length next to each other in series.
If you have a high afterload, will your heart be eccentric or concentric?
Concentric, sarcomeres stacking on top of each other.
If you have an MI, is it likely to cause eccentric or concentric LVH?
Eccentric
Why are thyroid levels difficult to measure and can go undetected?
Difficult to quantify amount of hormone in circulation, because it’s fat soluble and hangs inside oily areas in the plasma proteins.
What is a giveaway for hyperthyroidism?
Increased HR at REST.
Thyroid gland hangs out next to the ____ which is next to _____
Thyroid cartilage; larynx
Thyroid has nodules on it which is what and does what?
Parathyroid gland; parathyroid hormone/controller of calcium levels in the blood
What controls calcium levels in blood?
Parathyroid gland
When someone has a large thyroid gland, and its visible, its called
goiter
the thyroid gland has ____ vascular beds
rich; especially for how much tissue the thyroid is.
What is the reason for a rich vascular bed in the thyroid gland?
so it can take the thyroid hormone and spread it
what controls the muscles of the voice box (larynx)?
neurons that are housed in VAGUS nerve, which then branches off into LARYNGEAL NERVE
What kind of muscles are the voice box
skeletal
what is special about the right recurrent laryngeal nerve?
wraps around right subclavian artery and back up towards the thyroid gland, and then goes BEHIND the thyroid gland to the voice box.
What is special about the left recurrent laryngeal nerve?
wraps all the way under the aortic arch, before coming back up to larnyx.
alternate name for the recurrent laryngeal nerve
AFTER it comes back around the artery and its heading up, sometimes its called the inferior laryngeal nerve.
What is the laryngeal nerve important for?
speaking lmao. if they cut ONE, they’ll have a raspy voice/have a hard time speaking. If they cut both, they will never be able to talk.
thyroid hormone is made of one of two compounds
t3 or t4
what does the T stand for in the thyroid t3/t4?
Tyrosine
What does the number stand for in t3/t4?
how many iodides are stuck to the tyrosine
What % of T4 is released by thyroid gland?
93%
What % of t3 is released by thyroid gland?
7%
whats another name for t4?
thyroxine, thyroid hormone.
T3 chemical name is
3,5,3-TriiodoTHYRONINE
if we have 1 iodide attached to tyrosine, what is it called? 2?
monoiodoTYROSINE; diiodoTYROSINE
at how many iodides do you need another ring?
once you get to t3
how much iodine do we need in diet a year to make thyroid hormone? whats the main source?
50mg of iodide, table salt.
Main controller of DIRECT thyroid gland activity?
TSH - Thyroid stimulating hormone
also called thyrotropin
When TSH levels increase, what happens?
more t3/t4 dumped into blood
Where does TSH come from?
pituitary gland
What part of pituitary gland releases TSH?
anterior pituitary gland (adenohypophysis)
What controls the pituitary gland?
hypothalamus
What is the hypothalamus?
central controller monitoring blood, infection and temperature levels, and is constantly monitoring the conditions to adjust amount of TSH released from pituitary gland.
how does the hypothalamus talk to the pituitary gland?
TRH.
What does TRH stand for?
Thyrotropin releasing hormone
What is the nickname for TSH?
Thyrotropin
Total flowchart of t3/t4 release from the top
Hypothalamus-> releases TRH
TRH -> binds to pituitary gland
pituitary gland -> releases TSH
TSH -> binds to thyroid gland
Thyroid gland-> predominantly releases thyroxine (t4), and in smaller amounts t3
How does t3/4 move around in the blood? (3 ways)
attaches to carrier proteins in the blood.
They are lipid soluble, so they hitch a ride predominantly on TBG (both t4 and t3)
They also bind to thyroxine binding pre-albumin (less common)
Also just bind to albumin
What does TBG stand for?
thyroxine binding globulin
where are the carrier proteins that carry thyroxine created?
in the liver
if you have a liver failure pt, wont travel as well.
What thyroid hormone mostly shows up to cells?
T4, of course.
How do thyroid hormones cross cell wall?
very lipid soluble, so they cross by themselves.
Once inside cell wall, how do thyroid hormones get to nucleus?
hitch onto carrier proteins in there.. didnt specify what they are.
Are thyroid hormones allowed through nuclear pores?
yes
what passes through the nuclear pores fairly easily? to bind to what?
t3 and to some extent t4 (will explain later).. bind to thyroid hormone receptor
what happens when thyroid hormone receptor is bound to inside the nucleus?
turns on genes, which will ramp up cell processes.
cell growth, metabolic rate increases (which will increase o2 consumption, glucose absorption, etc.)
does blood pressure go up with hyperthyroidism?
no, typically just elevated heart rate.
Its because enhanced cardiac output is a function of reduced SVR.
What changes with hyperthyroidism and increased o2 consumption?
resp rate OR depth will have to increase
if you grow up in absence of thyroid hormone, what severe deficiencies can occur?
CNS, neuro development.. can lead to behavior issue, cognition, memory, etc.
really its for all growth and development.
what happens to cholesterol with hyperthyroidism?
decreased blood cholesterol levels, because cholesterol is used up to build all this shit that hyperthyroidism requires.
How long does it take for thyroid hormone to take effect?
AT BEST, with a ton of release, it will take 6-8 hours for it to manifest changes.
With a normal thyroid hormone output, takes 10 days for effects to peak.
there are conditions like a thyroid storm can happen quick, but generally speaking its longterm
If we have a tumor in the pituitary gland that is hypersecreting, this will result in
increase in TSH, which increases release of thyroid hormone.
The changes that occur will be sensed by hypothalamus, so the hypothalamus will react by decreasing/stop releasing TRH.
blood work will show: high tsh, high thyroid hormone, increased metabolic rate, absent TRH
if we have a tumor in the thyroid gland, it will result in?
extra thyroid hormone released, increasing metabolic rate.
sensed by the hypothalamus, which will stop secreting TRH.
blood work will show: Absent TRH, Absent TSH, elevated thyroid hormone, increased metabolic rate.
if we have a tumor in the hypothalamus, it will result in
increased TRH, TSH, thyroid hormone.
everything is fucking high. metabolic rate, yep.
it is possible that the pituitary gland would sense something is wrong and slow down, but we arent going that deep in this class
T4 is mostly delivered to the cell, what happens when it gets inside cell?
one of the iodides is pulled off via iodinase, to make it T3.
therefore, t3 is predominant form that attaches to thyroid hormone receptor.
where is the majority of t3 produced in the body?
tissues turning t4 into t3
can t4 make it into the nucleus?
yes, but majority of the effects is produced by t3 binding.
everything increases with hypethryroidism except
blood pressure
Graves disease
autoimmune disorder where body produces antibodies that interact with TSH receptors, that activates those receptors.
What tumor would simulate the same labs as graves disease?
Thyroid gland tumor.
NOT pituitary…
graves disease causes hyperactivity of TSH RECEPTOR, which is found in the thyroid gland.
eyes bulging is called? whats the concern with it?
exopthalmos
cornea damage from them being exposed.
If the body has antibodies that destroy thyroid gland, until its gone, whats it called? how does it start out?
hoshimotos thyroiditis; irritation to thyroid gland.
where is hoshimotos disease more common?
Asian folks
what else causes decrease of thyroid hormone?
general lack of iodine.
dont have the building blocks to produce t3/t4
what will the labs look like for iodine deficiency?
high TRH, high TSH
What will the size of the thyroid gland be with iodine deficiency?
huge, because TSH is still stimulating it in great amounts, just cant make the thyroid hormone.
how can you treat thyroid cancer?
radioactive iodine, since thyroid gland is mostly the only thing that uses iodine.
obviously, you can just cut it out too but thats messy due to vasculature.
Whats the radioactive iodine called?
I131
If we have a massive amount of iodine intake, what can happen?
actually interferes with thyroid glands ability to make hormone, which in turns drops the amount of thyroid hormone produced.
the system gets overwhelmed, and is related to REDOX reactions. need a certain amount of oxidative stress, and too much iodine will “cook” this system.
can be used to treat hyperthyroidism.
What drug is packaged in a solution with high iodine?
amiodarone
be careful with giving too many BOLUS doses of amio, can mess with thyroid hormone…
what causes exophthalmos?
excessive thyroid hormone.
how is one way you can tell that a goiter is due to hyperthyroidism vs hypothyroidism?
both cause goiter, but only hyperthyroidism causes exophthalmos
why does SVR decrease with hyperthyroidism?
with increased demand for nutrients, the vessels have to dilate to increase nutrient delivery.
can hyperthyroidism alter pulse pressure?
yes it can widen it. systolic up and diastolic down, with no change to MAP
What also can lower lab wise with cholesterol being low during hyperthyroidism? what about hypothyroidism?
triglycerides will lower with cholesterol during hyperthyroidism.
with hypothyroidism… causes atherosclerosis due to less cholesterol being used for thyroid hormone, so they have elevated cholesterol which causes atherosclerosis.
THIS REDUCES COMPLIANCE, I CAN SEE HIM ASKING IF HYPOTHYROIDISM INCREASES OR DECREASES COMPLIANCE
will patients take their synthroid when prescribed?
incredibly low patient compliance, people hate taking it because it messes with their ability to sleep/relax, heart palpitations, restlessness.
cardiogenic shock
heart can pump out as much as its supposed to.
e.g.: MI
“Other shock”
venous return pathologies, such as embolism.
Neurogenic shock
what you induce with volatile anesthetics, taking nervous system offline.
Or doing a high level spinal block.. higher, the riskier.
Anaphylactic shock: which vessels matter more? What causes it?
body panics when it sees something it doesnt like, histamine release from mast cells. Histamine takes away tone from vessels, and if this occurs in the veins, problem becomes much more serious if veins arent returning blood to the heart. Arteries still a concern but not as serious as the veins.
peanut/latex allergies
Septic shock
usually gram + bloodborne infection, dilating vessels, impeding venous return and nutrient delivery.
most common form of shock is
hypovolemic shock, either blood loss or dehydration.
What system compensates most for blood loss?
SNS
What % blood loss does cardiac output start to tank?
10%, but really starts at 20%
What blood loss % does arterial pressure start to tank?
20%
Why is the arterial pressure able to preserve itself longer than cardiac output?
SNS shunting blood to places needed and constricting all vessels.
Increased SVR, but decreased CO.
If you are only measuring arterial pressure during blood loss, why is this ineffecient?
arterial pressure hangs on longer than cardiac output does, so it may be too late once you see the drop in blood pressure.
for the example with 6 animals who lost blood, when is the % of normal arterial pressure past the point of survival? what is also specifically notable about the animals that died?
50% was okay and they recovered, but less than 45% of normal, those animals did not survive.
at 45% and 35% of normal, the animals initially recovered but then tanked after about 180 minutes.
Why were some animals able to recover before tanking again?
Catecholamine
Why were the animals to recover after 50% loss of arterial pressure?
catecholamines, kidneys reserving fluid, fluid shift from ICF/interstitial ECF to CV system,
what is non-progressive shock?
the animals that recovered from the blood loss, were able to preserve organ function.
What is progressive shock?
the animals that could not fully recover from the blood loss, lost major organ function then died.
How much blood volume can you lose and survive?
1L (20%)
Once you lose more than 20% of initial blood volume, things get dicey.
what % of blood volume lost quickly will probably not be survivable?
40%
Where are the 3 major blood storage pools that can be used during hemorrhage?
spleen has a large pool of readily available hgb/rbc’s
pulmonary has several hundred CCs that it can shunt into circulation if needed
GI system has bunch of blood in it and it can shunt it back over to needed spots.
What pressure increases first with compensation for heart failure?
Psf increases FIRST
How much does dig help a severely failing heart?
really not much lol 0.5L-1L/min maybe
As the days progress after heart failure, how does the RAP and Psf change?
Psf and RAP continue to rise as kidneys retain fluid, kinda peaks in the middle around day 2 and almost got back to 5L/min, but by day 8 it is almost completely tanked.
Kidneys retained too much volume after day 2/point C, because it thinks it needs to keep retaining fluid to bring up BP
How do you keep the body from killing itself as the days go on retaining more and more fluid?
diuretics
How can we monitor fluid volume with just an art line?
Pulse pressure variation.. if theres more than 10mmHg variation in PP with ventilation, may need a 100-250mL bolus.
we used this in Peds called pulsus paradoxus
