56 Questions
What is the average size of arteries in the systemic circulation?
4mm
Which component of the circulatory system is responsible for the exchange of fluid, nutrients, hormones, and oxygen between blood and tissues?
Capillaries
Which statement about veins in the systemic circulation is true?
They contain valves to prevent backflow of blood.
What is the function of arterioles in the circulatory system?
Regulating arterial blood pressure
Which component of blood is responsible for gas transport and transports oxygen?
Erythrocytes
What is the main function of plasma proteins in blood?
Participating in clotting reactions
Which coronary artery supplies most of the right ventricle and the posterior part of the left ventricle in 80-90% of people?
Right Coronary Artery (RCA)
Which coronary artery supplies the left side of the heart, including the left ventricle and left atrium?
Left Anterior Descending (LAD) artery
What determines coronary artery dominance by crossing the junction between the atria and ventricles to supply the posterior descending coronary branch (in 50% of population)?
Right Coronary Artery (RCA)
Which cardiac vein runs alongside the Left Anterior Descending (LAD) artery?
Great cardiac vein
What does blood returning from the left ventricle drain into?
Coronary sinus
Which coronary artery is associated with changes in EKG leads V1 – V4?
Left Anterior Descending (LAD) artery
In which EKG leads can changes be seen if there is an issue with the Left Circumflex (LCx) artery?
I, AVL, V5, V6
Which coronary artery is responsible for changes in EKG leads II, III, and AVF (inferior wall MI)?
Right Coronary Artery (RCA)
Which nerve innervates the SA node in the parasympathetic nervous system?
Right vagus nerve
What does increased sympathetic nervous system tone lead to in terms of heart function?
Increases heart rate
Which of the following best describes the relationship between the left and right heart?
The volume of blood entering the right heart must equal the volume of blood leaving the left heart
What is the determining factor for coronary perfusion pressure (CPP) under normal conditions?
Aortic Diastolic Blood Pressure (DBP)
What decreases coronary perfusion pressure?
Decreases in aortic (arterial) pressure
What is the normal area for the tricuspid valve?
$7-9$ cm2
What does coronary vascular reserve represent?
The difference between maximal coronary blood flow and autoregulated flow
In the context of myocardial oxygen balance, what does O2 supply rely on?
Arterial oxygen content
What is the formula to calculate arterial oxygen content ($CaO2$)?
$CaO2 = (SaO2 × Hgb × 1.34) + (0.003 × PaO2)$
Which condition increases myocardial O2 consumption?
$ ext{Decreased diastolic filling time}$
What is the normal area for the mitral valve?
$4-6$ cm2
What determines coronary blood flow according to Poiseuille's Law?
Change in pressure divided by resistance
What does coronary perfusion pressure represent?
Aortic Diastolic - LV end-diastolic pressure
Which law is an adaptation of Ohm's law in medicine, incorporating vessel diameter, viscosity, and tube length?
Poiseuille's law
What does Reynold's number predict when it is greater than 4000?
Mostly turbulent flow
In hemodynamics, what is the measure of the friction that impedes flow?
Resistance
What determines blood viscosity?
Hematocrit and body temperature
According to Poiseuille’s Law, how is the flow rate of liquid through a capillary tube related to the radius of the tube?
Directly proportional to the radius
What does Poiseuille’s Law show about the influence of vessel radius on resistance and flow in the body?
Changes in vessel radius have the most influence on resistance and flow
What can be calculated from the known relationship: F = ∆P / R?
Resistance
What variable changes most rapidly in the body quantitatively and physiologically?
Vessel diameter
What does Ohm's law form the basis for understanding in hemodynamics?
The relationship among blood pressure, blood flow, and resistance to blood flow
What is the function of the primary function of the right heart?
Pumping blood to the lungs
What is the main function of the left heart?
Pumping blood to the body
What valve does blood pass through when leaving the left ventricle?
Aortic valve
What is the function of chordae tendinae in the heart?
Preventing eversion of mitral valve during ventricular systole
What does the pericardial cavity contain?
10-25 mL of serous fluid for lubrication
Which surface of the heart is mainly formed by RV and partly by RA on the right, and LV on the left?
Sternocostal (anterior) surface
What is the anatomy that lines the outer surface of the heart also called?
Epicardium
What does MAP – CVP / SVR represent in hemodynamics?
Cardiac output (CO)
Which chamber has to generate 6-7 times as much force as the other chamber in order to push blood through the systemic circuit?
Left ventricle
Which chambers are responsible for receiving blood from veins and adding to ventricular filling?
Atria
What component prevents backflow of blood from pulmonary trunk into right ventricle?
Pulmonary valve
Which structure serves as the cardiac pacemaker of the cardiac cycle?
SA node
In the cardiac conduction system, where does the impulse originate and travel to stimulate the myocardial cells of the atria?
Internodal fibers
What is the main function of gap junctions and intercalated discs in cardiac muscle?
Spread of the cardiac action potential
Which component is responsible for releasing calcium from the sarcoplasmic reticulum in cardiac muscle during excitation-contraction coupling?
Sarcoplasmic reticulum
What causes the binding sites on actin filaments to become exposed during excitation-contraction coupling in cardiac muscle?
$Ca^{++}$ release from the sarcoplasmic reticulum
During muscle contraction in cardiac muscle, what happens to the Z lines according to the sliding filament theory?
They shorten
Which protein is responsible for preventing actin-myosin interaction in cardiac muscle?
$Tropomyosin$
What is the main function of thick filaments in cardiac muscle?
$Actin-myosin$ interaction and cross-bridge formation
In cardiac muscle excitation-contraction coupling, what causes a conformational change that exposes binding sites on actin filaments?
Troponin
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