The heart and blood vessels Flashcards
Arteries
-Carry blood away from the heart
-Divide into arterioles
-Blood under high pressure
-Thick wall>Small lumen
Veins
-Carry blood to the heart
-Divide into venules
-Blood under low pressure
-Thin wall >large lumen
Capillaries
-Tiny vessels that link arteries and veins
-Walls are a single layer of endothelium>very permeable
Layers in the walls of arteries and veins
1-Outer layer of inelastic protein (collagen)
2-Middle layer of muscle and elastic fibres
3-Inner layer which surrounds the lumen called the endothelium
Blood pressure
-Is the force the blood exerts against the wall of a blood vessel
Valves
-Control the direction of blood flow (prevent back flow)
Muscle of the heart
-Cardiac muscle
What do the ventricles do?
-Pump blood OUT of the heart
What does the right ventricle do?
-Pumps blood to the lungs
Left ventricle
-Pumps blood to the head and body
-Longer circuit>wall is much thicker
Atria
-Two upper chambers of the heart
-Pump blood to the ventricles
-Short distance>thin walls
Valve on the right-hand side of the heart
-Tricuspid valve (three flaps)
Valve on the left-hand side of the heart
-Bicuspid valve (two flaps)
Valve that allows blood to flow out of the heart
-Semilunar valves
Deoxygenated blood
-Vena cava>Right atrium>Tricuspid valve>Right ventricle>Forced through semilunar valve and pulmonary artery to the heart and lungs
