Blood
What are the formed elements in blood and what is each one's purpose?
erythrocytes - carry O2
leukocytes - fight pathogens
thrombocytes - help with clot formation
Which side of the heart has a thicker myocardium and why?
The left side, it needs more forceful contractions since the systemic circuit is a high pressure, high resistance circuit
What occurs between the s2 (dub) and the s1 (lub) heart sounds?
diastole - ventricular filling
What is the pressure difference between two points in a blood vessel called?
(for example: the pressure difference between the aorta and radial artery?)
driving pressure
What are the two shockable heart rhythms?
Which heart rhythm is often shocked on TV but isn't shockable
ventricular fibrillation (Vfib)
ventricular tachycardia (Vtach)
asystole is not shockable
What are the components of plasma, and what percentage of plasma do they make up?
91%: water
7%: plasma proteins - globulins, albumins, fibrinogens
2%:
electrolytes
nutrients and wastes
dissolved gasses
Why are cardiac action potentials slower than neural action potentials?
the ventricles need time to fill with blood before they depolarize.
The slower action potentials provide time for this to happen between atrial depolarization and ventricular depolarization
what changes during isovolumetric contraction, and which of the heart valves are open?
only the pressure changes in the ventricles during isovolumetric contraction
all valves are closed to keep blood volume constant
Calculate the mean arterial pressure (MAP) for someone with a blood pressure of 140/80 mm Hg
MAP = (2*diastolic + systolic)/3
MAP = (2*80 + 140)/3
MAP = 100 mm Hg
What are the two main causes of shock? (all types of shock are subgroups based on these two main causes)
insufficient blood volume
or
insufficient cardiac output
What does hemoglobin get broken down into? What happens to those products afterward?
heme - broken into iron and bilirubin. Iron is recycled, bilirubin is excreted
Name all 4 valves of the heart and where each is located. (for example: between the ___ atrium and _____ ventricle)
tricuspid: between right atrium and right ventricle
bicuspid: between left atrium and left ventricle
pulmonary semilunar valve: between right ventricle and pulmonary trunk
aortic semilunar valve: between left ventricle and aorta
Explain what effects an increased preload has on stroke volume AND how it causes this.
increased preload --> increased stroke volume
preload is how much blood is filling the ventricles
increased preload --> increased EDV --> more blood ejected from ventricles --> increased stroke volume
What are the three factors that affect systemic vascular resistance?
blood viscosity - viscous blood will have more resistance
vessel length - longer vessels have more resistance
vessel radius - wider vessels have less resistance
What are the two types of myocardial infarction, which one is more severe and why?
NSTEMI - less severe - myocardial scarring is limited to the subendocardial side (inside)
STEMI - more severe - myocardium is scarred all the way through (transmural)
describe the negative feedback loop for erythropoiesis
hypoxemia triggers kidneys to release erythropoietin
erythropoietin stimulates red bone marrow to produce erythrocytes
as erythrocytes increase, hypoxemia declines, ending the feedback loop
What are two names for the inner membrane of the pericardium?
visceral pericardium
epicardium
Calculate a patients cardiac output given the following: (include proper units)
ESV: 40 mL
EDV: 110 mL
HR: 90 bpm
CO = HR x SV
SV = EDV - ESV = 110 - 40 = 70 mL/beat
CO = 90 bpm * 70 mL/beat = 6300 mL/min
Explain how elevated SVR would affect afterload and stroke volume. Give one example of what could cause elevated SVR
SVR is systemic vascular resistance, the resistance to flow in the systemic blood vessels.
If SVR is high it is harder for the heart to push blood through the systemic circuit, increasing afterload.
Increased afterload means more blood will remain in the ventricles.
An example would be atherosclerosis
What causes cardiac tamponade. How does this result in heart problems? (how does it affect stroke volume)
pericardial effusion - the pericardium fills with fluid. This constricts the heart, preventing adequate preload, lowering stroke volume
describe the 3 steps of hemostasis
1) vascular spasm - blood vessel constricts to limit blood flow to broken vessel
2) platelet plug formation - thrombocytes form a platelet plug at the broken vessel
3) coagulation - fibrinogens and clotting factors cause blood to clot at the broken vessel
What is the order of electrical stimulation through the cardiac electrical system?
SA node --> AV node --> bundle of His --> bundle branches --> Purkinje fibers
Describe the effects of contractility on the heart and give an example of what would increase and decrease contractility.
contractility is how forcefully the ventricles squeeze the blood during isovolumetric contraction.
increased contractility --> increased stroke volume since there is less blood remaining in the ventricles after contraction
positive inotropes increase contractility (epi)
negative inotropes decrease contractility (hypoxia)
Describe the flow of blood through the systemic circuit, pulmonary circuit, and the heart, starting at the vena cava.
Include all greater vessels, arterioles, and venules
vena cava -> RA -> RV -> pulmonary arteries -> pulmonary capillaries -> pulmonary veins -> LA -> LV -> aorta -> arteries -> arterioles -> systemic capillaries -> venules -> veins -> repeats
left heart failure is caused by problems in the ____________ circuit, which congests the ___________circuit, resulting in ___________ edema.
right heart failure is caused by problems in the __________ circuit, which congests the _________ circuit, resulting in ____________ edema.
systemic, pulmonary, pulmonary
pulmonary, systemic, systemic