Test 3 Study Guide Part 4 Flashcards
DIC stands for what?
Disseminated Intravascular Coagulation
Disseminated intravascular coagulation is what type of condition?
Why does it have this name?
A consumptive coagulopathy.
It is called this because degree of widespread coagulation will cause a depletion of clotting factors. You will therefore see an increase in clotting, and thrombosis which causes thrombocytopenia (decrease thrombocytes), which in turn causes hemorrhaging. So we see both excessive bleeding and excessive clotting.
What can cause disseminated intravascular coagulation disorder?
Anything which can elicit systemic inflamation and shock and activation of clotting cascades. AKA: Amniotic fluid Embolism: Retained dead fetus: Severe infection Cancer Transfusion with incompatible blood
How is DIC treated?
Remove cause (cancer, infection, retained dead fetus) Give low levels of heparin (breaks up clotting, allows factors to be freed up for other purposes)
What prevents an electrical impulse from traveling to the atrial myocardium from the vetricle myocardium and visa versa?
Fibrous skeleton (the fibrous skeleton is also what the valves of the heart are suspended in)
Which vessel in your body has the largest diameter of any vessel?
The inferior vena cava
Pulmonary Circulation:
Route:
Features of driving ventricle:
Route:
right ventricle -> pulmonary trunk -> pulmonary artery -> pulmonary capillaries -> pulmonary veins -> left atri
Features of driving ventricle:
- It is the right ventricle
- The right ventricle is thinner, as it must only drive blood to the lungs and back to the heart
- The pumping of the left ventricle is sufficient to keep blood pressurized through the capillaries and back into the heart.
Systemic Circulation:
Route:
left ventricle -> aorta -> arteries -> arterioles -> capillaries -> venules -> veins -> (inferior or superior) vena cava -> right atria
Features of driving ventricle:
- The left ventricle is thicker, as it must drive blood to the top of the head
- The left ventricle provides insufficient pressure to bring the blood back up the inferior vena cava
- This is because, in part, the severe number of capillaries and arterioles, which decrease blood flow rate.
Should the systemic circulation and the pulmonary circulation have the same flow rate?
How is this rate achieved if the left ventricle is more muscular and contracts with more force?
Yes, or we would see edema
The left ventricle must also deal with increased resistance
AV valves:
- Name:
- Two valves:
- Name: Atrioventricular valve - Two valves: tricuspid valve (right, has first to letters of right in its name) Mitral valve (left, bicuspid valve)
Chordae tendineae:
attach to the papillary muscle.
They stop the bicuspid and the tricuspid valve from prolapsing.
Semilunar Valves:
- Two names:
- Structural differences between semilunar valves and atrioventricular valves:
- Two names:
Pulmonary semilunar valve
Aortic semilunar valve - Structural differences between semilunar valves and atrioventricular valves:
Semilunar valves do not have chordae tendineae. They do not need them because they are under less pressure
In what ways does the atria facilitate blood flow?
The primary method is by promoting continuous flow of blood (They are partially empty and stretchable, which allows blood to flow into them while the atrioventricular valves are closed).
The secondary method is by contributing 20% of the fluid volume of the ventricle just prior to contraction.
How does the atria help to achieve continuous blood flow?
It has no valve to interrupt flow.
It is slightly empty when the atrioventricular valve closes, which allows fluid to continue flowing into it.
It is elastic, which allows it to hold even more fluid within it, further allowing fluid to flow into even though the atrioventricular valve is closed.
atrial contractions are incomplete, and so do not contract to the point where they exclude the inflow of blood.
It contracts only weakly, so it does not push blood back through the vein.
Atria relax right before ventricular contraction, which means that they are allowing inflow of blood during atrial contraction.
They also contract after the valve is open, and while the ventricles are filling
- Pressure in atria will be low
Is atrial contraction necessary?
No. They do not need to contract for you to live.
Two heart sounds:
Lub Dub
Lub:
- S1 (sound 1)
- Associated with the closing of the atrioventricular valve
Dub:
- S2 (sound 2)
- Louder (possibly because the sound isn’t dampened by the chordae tendonae
- Associated with semilunar valves closing
Heart:
- Diastole:
- Systole:
- If you do not specify which chamber you are taking about, then what is assumed to be the chamber you are speaking about?
- Diastole:
relaxed (diastole = dialysis, this is when its open and relaxed) - Systole:
Seized/contracted - If you do not specify which chamber you are taking about, then what is assumed to be the chamber you are speaking about?
Left ventricle (as it is kind of the most important)
Heart murmurs:
- Cause:
- Cause:
Abnormal blood flow in the heart, usually associated with valve issues
Rheumatic fever:
- Effects:
- Define:
- Effects:
Heart, nervous system, and joints. (it can attack valves in the heart, and cause murmurs) - Define:
An autoimmune disease caused in response to a streptococci infection. Host mimicry causes you to target antigens which are also present in your body.
Autoimmune damage from rheumatic fever can damage which two valves?
The mitral valve (bicuspid valve) or the aortic semilunar valve
Stenosis define:
The abnormal narrowing of a passage of the body
Mitral Valve Stenosis:
- Define:
- Causes:
- Define:
Calcification of the mitral valve. Decreased blood flow, causing a build up of blood pressure in the pulmonary system (pulmonary hypertension). To respond to the increased pulmonary pressure the right ventricle grows thicker and stronger. This makes sense, as the thickening of the left ventricle would do nothing to help blood pass through the mitral valve. - Causes:
One is rheumatic fever
Mitral Valve Prolapse:
- Define:
- Different forms:
- Relative Frequency:
- Cause
- Define: Mitral valve prolapses... - Different forms: Congenital Acquired - Relative Frequency: Most common cause of chronic mitral regurgitation. - Cause: It can be from lengthening of the chordae tendineae or, I imagine, tearing of the chordae tendineae (hypertension). also can be caused by excess valve leaflet material.
Atrial Septal Defect:
A hole in the atria which doesn’t close during development.
Results in poorer oxygenation of blood
Cardiac Cycle:
- Atrial systole
- Ventricular systole (S1, lub, the atrioventricular valves close)
- Atrial diastole begins during ventricular systole - Ventricular and atrial diastole (S2, Dub, the semilunar valves close)
End-diastolic volume:
The volume which occurs from filling during ventricular (and atrial) diastole (totally 80% of end-diastolyic volume) plus the blood contributed by atrial systole (20% end diastolic volume)
Stroke volume:
- Define:
- Resting stroke volume and why:
- Define:
The amount of blood ejected out of the ventricles during systole. - Resting stroke volume and why:
2/3 of end-diastolic volume. The extra third is only used during exercise to blood flow.
Systole phases:
- Isovolumetric contraction:
Atria relaxed, ventricles contract, occurs while all heart valves are closed therefore there is no change in volume! So we need a build up in pressure in order to open the semilunar valves - Ejection:
Isovolumetric contraction has built up enough pressure to open the semilunar valve, the blood is ejected into the aorta or pulmonary trunk
Diastole phases:
- Isovolumetric Relaxation:
Everything is in diastole, but there is not enough pressure yet to open the atrioventricular valve (the semilunar is also likely closed) - Rapid Filling:
Semilunar valve opens, both atria and ventricle in diastole - Atrial Contraction:
atrial systole, ventricle is still in diastole
Measuring the pressure in the brachial artery measures the pressure in which ventricle?
The left ventricle, as this is the only contribution to the pressure of systemic circulation.
How is blood pressure reported?
Systolic pressure of diastolic (pressure during left ventricular systole of pressure during left ventricular diastole)
- Pulse is left ventricular systole
Dicrotic Notch:
The dicrotic notch is a blimp in pressure, where the pressure falls faster then expected and the rebounds during the otherwise steady fall in pressure associated with diastole.
The dicrotic notch corresponds with the closure of the aortic semilunar valve (DUB, S2)
S1 is caused by:
S2 is caused by:
S1 is caused by:
- Ventricular systole closes the atrioventricular valves
- It will be associated with QRS (Ventricular depolarization), and occur right after it, as muscular polarization will cause ventricular contraction.
S2 is caused by:
- Pressure build up in the aorta
- it is associated with t wave (ventricular repolarization)
Quiescent period:
the period in which all four chambers are in diastole
the same as the rapid filling stage
When the heart rate is changed, what period is being changed?
The quiescent period. There is a shorter time in which all four chambers are open.
P:
QRS:
T:
P: Atria depolarizes (contracts
QRS: Ventricles depolarize
- As the ventricles contract the lub (S1) is heard as the atrioventricular valves close)
- The QRS covers atrial repolarization
T: Ventricles repolarize
- As the ventricles expand the dub (S2) is heard as the semilunar valves slam closed)
ECG detects what?
Voltage changes in myocardium (pacemakers are too small to detect)
What does it mean to say that a myocardium acts as a functional syncytium?
Syncytial is multiple nuclei within the same cytoplasm. The gap junctions make it so the cells essentially share cytoplasm.
Name three pacemakers:
Which is dominant?
Sinoatrial node is dominant.
The atrioventricular node and purkinje fibers.
What type of cells are pacemaker cells?
They are myocardium (related to heart muscle cells)
Pacemaker potential:
- Define:
- Alternative name:
- Define:
A DEPOLARIZATION (as opposed to a polarization) of the heart, caused by opening of Na+ channels (Hyperpolarization-activated cyclic nucleotide-gated channels) - Alternative name:
Diastolic depolarization (occurs during diastole
Explain the intrinsic rhythmicity of the heart:
Voltage gated K+ channels open, causing hyperpolarization.
HCN (hyperpolarization-gated cyclic nucleotides-gated) channel opens, causing gradual increase depolarization.
Eventually this depolarizes past and voltage gated DHP channels open allowing Ca2+ to open RyR2 causing the cell to depolarize.
Then repeat at K+ channels.
What else other than voltage can open hyperpolarization cyclic nucleotides?
cAMP
How does norepinephrine and epinephrine increase heart rate?
It binds to G-protein coupled receptors and then… it activates adenylate cyclase, which in turn makes cAMP which binds to hyperdepolarization cyclic nucleotides, openning then to allow sodium to depolarize the membrane.
How does acetylcholine decrease heart rate?
Muscarinic Ach receptors through G-coupled protein receptors activate K+ channels which dampen the depolarization of HCN and Ca channels
SA is not a uniform structure, what is it in actuality?
Many different regions of pacemaker cells, electrically separate, but capable of communicating through sinoatrial conduction pathways
Define sinoatrial conduction pathways:
These pathways help spread action potentials to depolarize both atria.
There is also an internodal pathway which connects to the atrioventricular node
Internodal pathway:
Connects the SA node to the AV node
What does the firing of the sinoatrial node correspond to?
Atrial contraction/p wave
Normal sinus rhythm:
The regular pacing of the heart (controlled by the SA node).
A defibrillator uses electrical current to put the SA node back in sync with the AV node if the normal sinus rhythm is off.
What does HCN stand for?
How did HCN channels get their name?
Hyperpolarization-activated cyclic nucleotide-gated channel
HCN channels are because they are activated by hyperpolarization, and cyclic nucleotides (cAMP) can bind to open to them.
