The Heart

The Heart

The Heart

• Position• Structure• Function• Electricity• Pathology• Diagnostic Tests

Position of the Heart

• Located between the lungs in the thoracic cavity

• Centered in the chest

Structure of the Heart

• The size of your heart is comparable to the size of your fist.

Structure of the Heart

• The heart is enclosed in a protective membrane called the pericardium.

– The inner layer: visceral pericardium

– The outer layer: parietal pericardium

Structure of the Heart

• The walls of the heart are mostly made up of myocardium (heart muscle)

– Consists of parietal pericardium, fatty tissue, coronary vessels, pericardial space, visceral pericardium, myocardium, and endocardium

– Turn to page 375

Structure of the Heart

SEPTUM

Left Right

Structure of the Heart

• 4 Chambers:– The upper chambers: the right & left atrium– The lower chambers: the right & left ventricle

• The atria are smaller, thinner than the muscular ventricles of the heart

• Myocardium in the left ventricle is thicker than the right ventricle– moves blood to greater distances in the body

Structure of the Heart

• 4 Valves

2 valves separating the atria and the ventricles• Bicuspid (Mitral) valve on the left side• Tricuspid valve on the right side

Structure of the Heart

2 valves exiting the ventricles

– Aortic Semilunar valve exiting the right ventricle

– Pulmonary Semilunar valve exiting the left ventricle

Structure of the Heart

• Bicuspid and Tricuspid valves

– Held in place by Chordae tendineae which helps prevent backflow

Function of the Heart

• Consists of a double-pump – Left side of the heart moves blood throughout the

body and returns it to the right atrium • (Systemic Circuit)

– Right side of the heart moves blood to the lungs and returns it to the left atrium • (Pulmonary Circuit)

Function of the Heart

• Blood Circulation

– Brings Oxygen and Nutrients to the body

– Removes Carbon Dioxide and wastes out of the body

Electricity of the Heart

• Electrical signals (impulses) rhythmically keep the heart pumping

• Each complete heartbeat is considered a “Cardiac Cycle”

• Each cycle takes approximately 0.8 secs

Electricity of the Heart

• Contractions of the heart– Systole

• Relaxation of the heart– Diastole

Electricity of the Heart

• Impulses follow a continuous pattern

– Sinoatrial node (SA) node– Atrioventricular (AV) node– AV bundle or bundle of His– Purkenje fibers

Pathology of the Heart

• Cardiac disease can be... Structural

Electrical

Pathology of the Heart

• Terms of structural problems– Angina pectoris– Cardiac tamponade– Cardiomegaly– Cardiomyopathy– Congestive heart failure– Coronary embolism– Endocarditis

Pathology of the Heart

• Terms of structural problems con’t– Incompetent valve– Mitral valve prolapse– Myocardial infarction– Pericarditis– Pericardial effusion– Rheumatic heart disease– Stenosed valve

Pathology of the Heart

• Terms for Electrical problems:– Bradycardia– Dysrhythmia– Extrasystoles

• PACs & PVCs– Fibrillation

• atrial & ventricular– Sinus dysrhythmia– Tachycardia

Diagnostic Tests

• Angiography• Cardiac catheterization• Echocardiography• Electrocardiography• Holter monitoring• Magnetic resonance imaging• Stress test

References• Causey, L. (Designer). (2011). small_fist [Image], Retrieved January 28, 2012,

from:http://www.aperfectworld.org/clipart/gestures/fist_small.png • [Image of electricity]. Retrieved January 30, 2012, from:

http://www.hsbwhistlestop.com/agents/express/img/2010_04/img_electric_lg.jpg • [Image of electrocardiogram]. January 30, 2012, from:

http://www.squarecirclez.com/blog/math-of-ecgs-fourier-series/4281• [Image of heart in thoracic cavity]. Retrieved January 28, 2012, from:

http://www.nottingham.ac.uk/nursing/practice/resources/cardiology/images/cut_away_chest.gif

• [Image of one way valve]. Retrieved January 30, 2012, from: http://www.swimmingpoolspares.com.au/index.php?cPath=79_106_161

• [Image of pericardium]. Retrieved on January 30 2012, from: http://www.lausd.k12.ca.us/Figueroa_EL/Fourth%20Grade/mysterytomedicine4.htm

• Louwinger, O. Whelan, G. & Taddei, M. (2007). The Human Body Book. New York, NY: Dorling Kindersley.

• Thibodeau, G. A. & Patton, K. T. (2010). The Human Body in Health & Disease (5th ed.). St.Louis, MO: Mosby Elsevier.