The major of the circulatory system;A. The heartB. The human circulatory systemC. A typical veinD. A typical arteryE. A typicai capillary (not shown)

1, Muscle wail of right ventricle2. fVfuscie wall of left ventricle

•3. Intraventricular septum-4. Right atrium (auricle)5. Left atria! wall

•6. Papillary muscles-7, Tricuspid valve of right ventricle• 8. Bicuspid valve of left ventricle.9. Pulmonary sernilunar valve

•10. Aortic serniiunar valve-11. Superior vena cava (to heart from head and arms)12. Inferior vena cava (to heart from body and legs)13. Pulmonary artery (to lungs)14. Pulmonary veins (to left atrium)15. Aorta16. Inominate artery (to head and right arm)17. Left common carotid artery (to head)18. Subciavian artery (to left arm)

>19, Epicardiurn (outer covering of the heart)20. Myocardium (muscle layers of the heart)21. Endocardium (membrane lining of heart chambers)

Principal structures of the circulatory system:22. Heart2.3. Kidneys24. Lungs (not shown)25. Spleen (not shown)26. Capillaries (not shown)27. Abdominal aorta28. Femoral arteries (red) and veins (blue)29. Arteries (red) to legs and veins (blue) from legs30. Subciavian arteries (red) and veins (blue)31. Arteries (red) to arms and veins (blue) from arms32. Arteries (red) to head and veins (blue) from head33. Wall of vein34. Vaive in. vein (forcing blood to flow in only one direction)35. Typical artery (3»layer structure)36. Tunica intema (inner lining tissues of artery)37. Tunica media (middle muscle layers of artery)38. Tunica externa (outer covering of connective tissue)

Abdominal aorta (21) The branch of the aorta taking blood to the viscera, kidneys and iegs.

Aorta (16) The largest artery of the body exiting the heart,Aortic semilunar valve (10) The valve between the aorta and left ventricle which prevents blood

from flowing back into the left ventricle,

Arteries (31, 32, & 35) Blood vessels which carry blood away from the heart,

Atrium, left (5) The chamber of the heart that receives oxygenated blood from the lungs andpumps it to the left ventricle.

Atrium, right (4 ) The chamber of the heart that receives deoxygenated blood from the body andpumps it to the right ventricle,

Auricle, left (5) The biological term (as opposed to medical) term for the left atrium

Auricle, right (4) The biological term (as opposed to medical) for the right atrium,Bicuspid valve of left ventricle (8) The valve between the left auricle and left ventricle which

prevents blood from flowing backward into the left auricle,

Bone marrow The spongy interior of large bones which produces blood cells.Capillaries The tiniest of the blood vesseis connecting the arterial and venous systems, and

through which materials enter and leave the circulatory system,Cardiac muscle The special muscle of which the heart is constructed. It contracts forcibly like

skeletal muscle, but is under involuntary control like smooth muscle.

Carotid artery (17) The main artery which takes blood to the head.

Diastole The relaxing phase of the heart's pumping cycle in which the auricles fill.

Endocardium (21) The membrane lining of heart chambers.

Epicardium (19) The outer covering of the heart

Femoral arteries (28) (red) The main arteries taking blood to the iegs.Femoral veins (28) (blue) The main veins exiting the legs, returning blood toward the heart,

Heart (22) The organ which pumps blood throughout the body.Hemoglobin! The red, iron-rich substance in red biood cells which carries carbon dioxide and

oxygen.Inferior vena cava (12) The main artery returning biood to the heart from the lower body, legs

and liver.Inominate artery (16) A branch from the aorta carrying blood to the head and right arm.

Intraventricular septum (3) The muscular wall dividing the left and right ventricles.Kidneys (23) The two organs mainly responsible for removing metabolic wastes, excess salts, and

water from the blood. Their product is urine.Longs The organs through which oxygen enters the blood and carbon dioxide exits.

Lymph The liquid which surrounds and bathes body cells and through which substances such asfood, water, wastes and hormones are transferred from the blood to the cells and vice versa.

Myocardium (20) Muscle layers of the heart.Papillary muscles (6) Muscles that help open the tricuspid and bicuspid valves.

' G i ossa ry (continued)

The liquid part of the blood. It is a complex amber substance composed of water, food,wastes, hormones, antibodies, and salts.

Pulmonary artery (13) An artery which takes deoxygenated blood from the right ventricle tothe lungs.

Pulmonary veins (14) Veins which return oxygenated blood to the left atrium from the iungs.

R©d blood cells More properly ca!led erythrocytes, these are non-nucleated (in humans) bloodcells containing hemoglobin which earn/ oxygen to body cells and carbon dioxide from them,

Serirailyrtar valve, pulmonary (9) The valve preventing back flow of blood between the pulmonaryartery and the right ventricle.

The voluntary muscles which move the body, Pressure from their contractionshelps force blood through veins back to the heart.

Smooth (visceral) muscles The involuntary muscles found chiefly in the digestive system andsmaSl blood vessels,

Spleen An abdominal organ which manufactures blood ceils, destroys worn-out blood celis, andacts as a reservoir of blood for emergencies,

Subciavian arteries (red) (30) Arteries which take blood to the arms,

Subciavian veins (blue) (30) Veins which return blood from the arms,

Superior vena cava (11) The main vein returning biood to the heart from the head and arms.

Systole The phase of heart contraction in which blood is pumped under pressure from one place tothe next,

Tricuspid valve of right ventricle (7) The valve preventing blood from back fiow between the rightauricle and right ventricle.

Tyniea externa (38) The outer covering of an artery.

Tunica ioteroa (36) The inner lining tissues of an artery,

Tonica media (37) The middle muscle layers of an artery.

Urine The waste fluid produced by the kidneys from filtered blood. It consists of water, metabolicwastes (chiefly urea) and salts.

Valve in vein (34) A structure in a vein which forces blood to flow in only one direction.

Ventricle, left (2) The largest and most powerful chamber of the heart which forces oxygenatedblood into the aorta and thence throughout the body.

Ventricle, right (1) The chamber of the heart which pumps deoxygenated blood to the lungs.

of vein (33) The main portion of a vein,

White blood cells More properly called leukocytes, these are actively mobile biood cells whichdestroy foreign bacteria and harmful antigens, manufacture antibodies, and repair cell injuries.They are an integral part of the immune system.

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