Systemic Circulation – delivers blood to all body cells and carries away waste Pulmonary Circulation – eliminates carbon dioxide and oxygenates blood (lung pathway)
Structure of the Heart Heart Size – about 14 cm x 9 cm (the size of a fist). Located in the mediastinum (space between lungs, backbone, sternum), The distal end of the heart is called the apex.
Fibrous Pericardium encloses the heart (like a bag) and has 2 layers visceral pericardium (inner) and parietal pericardium (outer, attached to diaphragm, sternum and vertebrae)
Pericardial cavity – contains fluid for the heart to float in, reducing friction Wall of the Heart Epicardium – outer layer, reduces friction Myocardium – middle layer, mostly cardiac muscle Endocardium – thin inner lining, within chambers of the heart
Heart Chambers & Valves Your heart is a double pump. Circulation is a double circuit: Pulmonary (lungs only) and systemic (rest of the body) Heart has 4 chambers: o 2 Atria – thin upper chambers that receive blood returning to the heart through veins.. Right and Left Atrium o 2 Ventricles – thick, muscular lower chambers. Receive blood from the atria above them. Force (pump) blood out of the heart through arteries. Right and left ventricle. Septum – separates the right and left sides of the heart
Valves of the Heart – allow one-way flow of blood. 4 total (2 Atrioventricular Valves (AV) & 2 Semilunar valves) o Left Atrioventricular valve – also called the bicuspid valve or mitral valve. Between left atrium and ventricle o Right Atrioventricular valve – also called the tricuspid valve. Between right atrium and ventricle Aortic Semilunar – or just aortic valve. Between the left ventricle and the aorta Pulmonary Semilunar, or just pulmonary valve. Between the right ventricle and the pulmonary artery.
Mitral = bicuspid (left side) Tricuspid (right side) Aortic and Pulmonary are both semilunar valves
Heart Actions Cardiac Cycle: One complete heartbeat. The contraction of a heart chamber is called systole and the relaxation of a chamber is called diastole. The beginning of ventricular systole- lub The end of ventricular systole- dub http://www.youtube.com/watch?v=riDPxasIz_ I http://www.youtube.com/watch?v=riDPxasIz_ I
Blood pressure is the force of blood against the walls of arteries. Blood pressure is recorded as two numbers—the systolic pressure (as the heart beats) over the diastolic pressure (as the heart relaxes between beats).
The average (normal) blood pressure for an adult is 120/80. This number varies by person and it is best if you know what is *normal* for you, so that you (or your doctor) recognize when something is not normal. SPHYGMOMANOMETER
The cusps (flaps) of the bicuspid and tricuspid valves are anchored to the ventricle walls by fibrous “cords” called chordae tendineae, which attach to the wall by papillary muscles. This prevents the valves from being pushed up into the atria during ventricular systole. Can you identify these parts?
Animation of Heart Contraction http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter22/animation __the_cardiac_cycle__quiz_1_.html
13.4 BLOOD VESSELS Blood Vessels: arteries, veins, capillaries ARTERIES : strong elastic vessels which carry blood moving away from the heart. Smallest ones are arterioles which connect to capillaries. VEINS - Thinner, less muscular vessels carrying blood toward the heart. Smallest ones are called venules which connect to capillaries. Contain valves.
Capillaries: Penetrate nearly all tissues. Walls are composed of a single layer of squamous cells – very thin. Critical function: allows exchange of materials (oxygen, nutrients) between blood and tissues.
Blood Clots can occur if blood does not flow properly through the veins - can occur if a person does not move enough
Major Blood Vessels Aorta - Ascending Aorta, Aortic Arch, Descending Aorta, Abdominal Aorta. The aorta is the largest artery. (leaves left ventricle) Pulmonary Trunk – splits into left and right, both lead to the lungs (leaves left ventricle) Pulmonary Veins – return blood from the lungs to the heart (connects to left atrium) Superior and Inferior Vena Cava – return blood from the head and body to the heart (connects to right atrium)