Human Anatomy and Physiology of the Human Body

Human Anatomy and Physiology 260 - Midterm 1

Cardiovascular Anatomy

Arteries:
• Carry Blood from the heart to the tissues
• Gradually decreasing in size of vessels o Arteries - Transportation of red blood cells away from the heart o Arterioles - Smaller, lead from the arteries to the capollaries o Capillaries - Gas exchange (tissue level)
• 3 layers of wall: o 1. Tunica Adventitia (Tough outer layer) o 2. Turnica media (Middle smooth muscular layer, changes the diameter of the blood vessel (constriction and dialation)) o 3. Turnica intima (Very smooth inner layer) o Smooth inner lumen and elastic lamina to maintain shape
• 3 types of arteries: o Elastic (ex. Abdominal Aorta)
 Largest in size
 Allows for high degree of expansion between heart beats o Muscular (ex. Femoral artery)
 Distributing arteries
 Regulate flow of blood to different parts of the body o Arterioles (ex. Tributaries)
 Narrow lumina
 Thick muscular walls
 Blood pressure mainly regulated by the degree of muscular tone
Veins:
• Return deoxygenated blood to the heart o Except Pulmonary veins carrying blood from the lungs to heart
• Gradually increasing in size of vessels o Capillaries o Venules o Veins
• Same layer design as the arteries
• Thinner tunica media (Less ability to constrict)
• Similar in structure to arteries
• Walls are thinner due to lower blood pressure
• Poorly developed muscular layer
• Accompanying (communicating) veins for extremity arteries
• Three types of veins: o 1. Large (ex. Inferior vena cava)
 Wide bundles of smooth muscle
 Well developed tunica adventitia o 2. Medium (ex. Great saphenous vein)
 Have valves to maintain direction of flow
 Musculovenous pump - squeezes the vein to propel the blood to the heart o 3. Small (Venules)
 Unite to form venous plexuses
• Veins have valves - Which helps the blood return to the heart without falling back

arteries veins thick walls (due to smooth muscle in tunica