Artificial pacemakers can be used to treat a patient suffering from:
1. a myocardial infarction
2. atherosclerosis
3. a third degree AV node block
4. mitral stenosis
The sinoatrial node is the normal pacemaker of the human heart because it:
1. can form action potentials that can spread throughout the rest of the heart
2. depolarizes to its threshold potential before other pacemakers in the heart
3. is located in the top of right atrial wall
4. is most likely to form an ectopic focus
What is the ejection fraction that is achieved by the left ventricle in a healthy heart?
1. 10(--)15%
2. 25(--)33%
3. 60(--)70%
4. 98(--)100%
How can adrenaline have different effects on blood vessels - vasodilation in skeletal muscle but vasoconstriction in the skin?
1. sympathetic fibers secrete epinephrine in the muscle and acetylcholine in the skin
2. bradykinin stimulates constriction of arterioles in the dermis
3. the muscles have cholinergic sympathetic fibers and the skin has adrenergic fibers
4. the muscle arterioles and the skin arterioles have different types of receptors for adrenaline
Tissue death (necrosis) due to inadequate blood supply to the affected area, such as the heart, is:
1. coronary thrombosis | 2. angina pectoris |
3. ischemia | 4. infarction |
A chest pain or pressure, usually due to not enough blood flow to the heart muscle, is known as:
1. hypoxia | 2. infarction |
3. angina | 4. diaphoresis |
Atria can completely empty during ventricular filling due to:
1. A-V node
2. A-V bundle
3. S-A node
4. Purkinje fibers
The period that extends from the onset of atrial depolarization until the onset of ventricular depolarization is shown in an ECG as:
1. QRS complex
2. S-T interval
3. P-Q interval
4. QRS-T interval
The arrhythmia that results in cardiac arrest followed by death in the absence of treatment and therefore considered most serious is:
1. Tachycardia
2. Sinus bradycardia
3. Atrial flutter
4. Ventricular fibrillation
QRS complexes on the ECG tracings show that:
1. The atria are depolarizing.
2. The ventricles are depolarizing.
3. The ventricles are repolarizing.
4. The heart is at rest.
In the nodal tissue of the human heart the last to get activated is/are:
1. SA node
2. AV node
3. AV bundle
4. Purkinje fibers
In a normal ECG, The T wave represents:
1. | ventricular depolarization | 2. | atrial repolarization |
3. | ventricular repolarization | 4. | atrial depolarization |
The normal pacemaker of the human heart is the remnant [derivative] of:
1. chordate tendinae
2. bundle of His
3. conus arteriosus
4. sinus venosus
The build-up of fats, cholesterol and other substances in and on the artery walls is known as:
1. | arteriosclerosis | 2. | atherosclerosis |
3. | aneurysm | 4. | anastomosis |
Branch of aorta that supplies the oxygenated blood to the muscles of the heart is:
1. coronary arteries.
2. common carotid arteries.
3. coronary sinus.
4. great cardiac veins.