BIO 101: Anatomy and Physiology 2
Lecture Outline
THE HEART
I. INTRODUCTION:
The HEART is a hollow, cone - shaped organ, about the size of a closed fist and is located in the middle of the mediastinum of the thoracic cavity. It weighs about 300 grams in adults.
This muscular organ rests on the diaphragm and is tilted anteriorly and laterally towards the left. About two - thirds of the mass of the heat lies to the left in relation to the body's midline.
This four - chambered pump beats approximately 72 times per minute; 4320 times/hour and 103,680 times/day. It pumps blood through blood vessels at an estimated 100, 000 km. or about 60, 000 miles. Approximately, 5 liters of blood is pumped from the heart each minute.
Top of Page
II. The Anatomy of the Heart:
A. The Pericardium - a connective tissue membrane that surrounds and protects the heart
2 Layers: a. Fibrous Pericardium: superficial layer composed of dense irregular connective tissue
b. Serous Pericardium: deep layer; has 2 layers
b.1. Parietal Layer - outer layer of the serous pericardium
b.2. Visceral Layer (aka Epicardium) - inner layer of the serous pericardium
** Pericardial Cavity
** Pericardial Fluid
*** PERICARDITIS
Top of Page
B. The Heart Wall
1. The Epicardium - also known as the visceral layer of the serous pericardium; external layer of the heart wall
2. The Myocardium - cardiac muscle tissue; makes up the bulk of the heart and is responsible for the pumping action of the heart.
3. The Endocardium - a thin layer of endothelium, which provides a smooth inner lining for the heart
C. Chambers of the Heart: Has 2 superior chambers and 2 inferior chambers
a. Right and Left Atria: 2 superior chambers
Interatrial Spetum: separates the atria
Fossa Ovalis: a remnant of the FORAMEN OVALE
FORAMEN OVALE - an opening in the interatrial septum of the fetal heart, which closes soon after birth.
Pectinate Muscles
Auricle
b. Right and Left Ventricles: 2 inferior chambers
Interventricular Septum: separates the 2 ventricles
Top of Page
c. Atrioventricular Valves (Right and Left AV valves): lie between the atria and ventricles
c.1. Tricuspid Valve - consists of three cusps; lies between the right atrium and the right ventricle
c.2. Bicuspid Valve: also known as the mitral valve
- consists of 2 cusps; lies between the left atrium and the left ventricle.
c.3. CHORDAE TENDINAE
c.4. Papillary Muscles
d. SEMILUNAR VALVES: This allows ejection of blood from the heart but prevents flow of blood back into the heart.
d.1. Pulmonary Semilunar Valve - lies in the opening between the right ventricle and the pulmonary trunk.
d.2. Aortic Semilunar Valve - lies in the opening between the aorta and the left ventricle.
e. Disorders of the Heart Valves:
e.1. Rheumatic Fever
e.2. Stenosis
Top of Page
Comparison between the Right and Left Ventricles
RIGHT VENTRICLE LEFT VENTRICLE
1. Has a thinner muscular wall 1. Has a thicker wall
2. Pumps blood to the lungs with fairly low 2. Pumps blood to all other parts of the body
pressure at a greater pressure
3. Pumps blood to the pulmonary circulation 3. Pumps blood to the systemic circulation
4. Works at a minimal value 4. Works harder to maintain the same rate
of blood flow to the systemic circulation
_________________________________________
This is only a general outline of the Heart Anatomy.
________________________________________________
------------------------------
To my students: There is much that will be discussed and presented in the lecture that is not included in this outline.
All that will be discussed during the lecture is test-material whether or not it is included in this outline.
----------------------------
Top of Page
