What is the primary function of the Sinoatrial node (SA) node in cardiac electrical conduction?

• Accelerating the heart rate

• Initiation of the action potential

• Delaying the electrical impulse between the atria and

  ventricles

• Contracting the atrial muscle

In an EKG, what does the QRS complex represent?

• Ventricular repolarization

• Atrial repolarization

• Atrial depolarization

• Ventricular depolarization

In the context of cardiac excitation-contraction coupling, what triggers calcium release from the sarcoplasmic

reticulum in cardiac myocytes?

• Calcium influx through DHPR

• Sodium influx

• Phosphorylation of troponin

• onformational changes of DHPR

Which ion plays a crucial role in initiating the cardiac action potential and contraction?

• Chloride (Cl-)

• Sodium (Na+)

• Calcium (Ca2+)

• Potassium (K+)

During cardiac myocyte relaxation, Ca²⁺ will have to be extruded from the cytosol.

Which of the following will NOT take part in the Ca²⁺ removal mechanism?

• Voltage-gated Ca²⁺ channel

• Sarcoplasmic reticulum Ca²⁺-ATPase pump (SERCA)

• Plasma membrane Na⁺/Ca²⁺ exchanger

• Plasma membrane Na⁺/K⁺-ATPase pump

All of the following cause the heart to contract vigorously; EXCEPT

• Increased plasma epinephrine

• Hypercalcemia

• Hyperkalemia

• Increased sympathetic outflow

What is the correct placement of EKG leads?

• Lead I : Left arm (negative) Right arm (positive)

• Lead II : Right arm (negative) Left leg (positive)

• V1 : Right edge of sternum in the 2nd intercostal space

• V2 : Left edge of sternum in the 2nd intercostal space

The highest total cross-sectional area of blood vessel is found in                         .

• Aorta

• Arteries

• Capillaries

• Veins

Which one of the following is NOT a factor that affect blood flow?

• Heart rate

• Resistance

• Blood viscosity

• Diameter of blood vessel

Which of the following statement is true about blood pressure?

• mABP can be increased by increasing cardiac output with vasodilation.

• mABP = 1/3 Pulse pressure + Diastolic pressure

• Korotkoff sounds are produced by laminar blood flow.

• Parasympathetic activity can increase blood pressure.