The _______ of the conduction system is known as the pacemaker.
a. SA node
b. AV node
c. AV bundle
d. left bundle branch
Introduction:
In animals, the heart is a muscular organ which pumps blood via circulatory system throughout the body. Blood gives oxygen and nutrients to the body, and removes metabolic wastes. The heart is placed just behind and moderately left of the sternum (breastbone) in humans.
In humans, birds and some other mammals, the heart is partitioned into four chambers: the upper right and left atria and the lower right and left ventricle.
A pacemaker is a medical machine that is situated at the top of the heart's right atrium to help control abnormal (or unusual) heart rates. This machine utilizes electrical pulses to imply the heart to beat (or vibrate) at a normal rate. The pacemaker is used to treat arrhythmias. Arrhythmias are the problem with the rhythm or rate of the heartbeat.
Answer to Problem 1PL
Correct answer:
The correct answer is option (a) SA node.
Explanation of Solution
Explanation/justification for the correct answer:
Option (a) SA node. The natural pacemaker of the heart is SA node. These cells can produce electrical impulses spontaneously. The chief function of a sinoatrial (SA) node cell is to begin the action potential of the heart so that it can pass through the whole heart and provoke contraction. So, this is the correct option.
Explanation for incorrect answer:
Option (b) AV node. The tricuspid valve and the mitral valve are identified as the atrioventricular (AV) valve and attach the atrium to the ventricle. Both valves are positioned between the upper chambers (atria) and lower chambers (ventricles) and prevent the backflow of the blood from the ventricles into the atria during systole. So, this is an incorrect option.
Option (c) AV bundle. A bundle of specialized muscle fibers controls the heartbeat by conducting impulses from the right atrium of the ventricle is known as the AV bundle. AV bundle also termed as bundle of His. It transmits impulses from the ventricular note to the ventricles of the heart. So, this is an incorrect option.
Option (d) left bundle branch. The left bundle branch carries electrical signals to the bottom of the heart and causes the ventricles to beat. So, this is an incorrect option.
The SA node of the conduction system is known as the pacemaker. Hence, the correct answer is option (a) SA node.
Want to see more full solutions like this?
Chapter 45 Solutions
LABORATORY MANUAL FOR HUMAN ANATOMY & PH
- The term _________________ ECG means a record or picture of the electrical activity of the heart electr/o means electric, and cardi/o means heart.arrow_forwardThe term endarterial means pertaining to the interior or lining of an artery. ________ _________ ________ ________arrow_forwardThe Common Iliac artery is a: A. Visceral branch of the aorta B. Parietal branch of the aorta C. Not a branch of the aorta D. Terminal branch of the aortaarrow_forward
- Obstruction of this vessel causes a more severe myocardial infarction in comparison to other vessels. a. circumflex branch b. right marginal vein c. left coronary artery d. anterior interventricular brancharrow_forwardAn x-ray of a person with low back pain shows a distention of the largest blood vessel in the thoracolumbar area. This person probably has a/an __________. Group of answer choices a. thoracic aortic aneurysm b. dissecting aneurysm c. cerebral aneurysm d. deep vein thrombosis e. abdominal aortic aneurysmarrow_forwardBlood is supplied to the left side of the head and neck by the ______ artery. A. Left Subclavian B. Brachiocephalic C. Left Common Carotid D. Right Common Carotidarrow_forward
- The linear guide for the axillary artery has the imaginary line parallel to the long axis of the _____ upper extremity A. Adducted B. Bifurcated C. Abducted D. Rotatedarrow_forwardA pathologist is looking at a histological section of aorta stained to demonstrate the many wavy fibers that provide the aorta with the flexibility to stretch and then return to its original shape. These fibers are also found in substantial numbers in the A. biceps muscle B. liver C. mesentery D. spleen E. vocal cordsarrow_forwardSelect the letter of the choice that best completes the statement. The treatment for conduction defect may includea. coronary bypass.b. cardiotonics.c. insertion of a pacemaker.d. angioplasty.arrow_forward
- The Right internal carotid artery is a: A. Visceral branch of the aorta B. Parietal branch of the aorta C. Not a branch of the aorta D. Terminal branch of the aortaarrow_forwardThe transverse aorta continues as the: A. Parallel aorta B. Ascending aorta C. Descending sigmoid aorta D. Thoracic Aortaarrow_forwardChoose the best answer Blood moving from the left atrium to the left ventricle passesthrough which of the following valves?a. bicuspid valveb. tricuspid valvec. aortic semilunar valved. pulmonary semilunar valvearrow_forward
- Medical Terminology for Health Professions, Spira...Health & NutritionISBN:9781305634350Author:Ann Ehrlich, Carol L. Schroeder, Laura Ehrlich, Katrina A. SchroederPublisher:Cengage Learning
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage LearningEssentials of Pharmacology for Health ProfessionsNursingISBN:9781305441620Author:WOODROWPublisher:Cengage