Life Processes Circulatory System The Blood Vessels The

Life Processes Circulatory System.

The Blood Vessels: The blood vessels of the circulatory system would be subdivided into Arteries Veins Capillaries

Arteries: Things to note: (i) All arteries lead away from the heart (ii)All arteries carry oxygenated blood with the exception of the pulmonary artery. (iii)Arteries have a thick elastic arterial wall that can withstand the pressure of the blood flowing away from the heart.

Veins: Things to note: (i) All veins lead toward the heart (ii)All veins carry deoxygenated blood with the exception of the pulmonary vein. (iii)Veins have semi lunar valves that prevent the backflow of blood

Differences between arteries and veins. Arteries carry oxygenated blood, away from the heart except pulmonary artery These are mostly deeply situated in the body These are thick-walled, highly muscular except arteries of cranium and vertebral column These posses narrow lumen Valves are absent These are reddish in color These show spurty movement of blood giving pulse Blood in arteries moves with pressure Arteries empty up at the time of death If arterial wall is injured, the blood comes out like a ‘fountain’ in a large area all around the artery

Differences between arteries and veins continued. Veins: 1. Veins carry deoxygenated blood, towards the heart except pulmonary veins 2. These are superficial and deep in location 3. These are thin-walled 4. These posses wide lumen 5. Valves are present which provide unidirectional flow of blood 6. These are bluish in color 7. These show sluggish movement of blood 8. Blood in veins moves under very low pressure 9. Veins get filled up at time of death 10. If venous wall is injured, blood comes out, collects in a pool in a small area around vein

Capillaries: Capillaries are only one cell thick, they are very leaky. This is ideal since substances e. g. Oxygen and glucose must pass out and carbon dioxide move in

The Human Heart: The human heart is a muscular pump that pushes blood around the body it is made up of a type of muscle called cardiac muscle.