Transcript Chp.6 Circulatory System 2

Circulatory System
Blood vessels
Arteries, capillaries, veins are tube-like
in construction
 They transport blood to and from the
heart and then to various body tissues

Blood vessels

Arteries
– Thick-walled muscular and elastic tubes
that carry oxygenated blood from heart to
capillaries
– Largest artery is the aorta
Blood vessels

Capillaries
– Minute, thin-walled vessels that connect
smaller arteries to veins
– Provide tissues with nourishment and
elimination of waste products
Blood vessels

Veins
– Thin-walled blood vessels
– Less elastic than arteries
– Contain cup-like valves to prevent back
flow, and carry blood containing waste
products from capillaries back to heart
– Located closer to outer surface off body
than arteries
The Blood
Nutritive fluid circulating through the
circulatory system
 Approximately 80% water
 Composed of red and white corpuscles,
platelets, plasma and hemoglobin

The Blood
Sticky, salty fluid
 Normal temperature of 98.6 degrees F
 Makes up 1/20 of body weight
 About 8-10 pints fill adult vessels
 Bright red in arteries
 Dark red in veins (except pulmonary)

Blood Composition

Red Corpuscles (red blood cells)
– Also known as erythrocytes
– Produced in red bone marrow
– Contain hemoglobin (a complex iron
protein that gives the blood its bright red
color)
– Carry oxygen to cells
Blood Composition

White Corpuscles (white blood cells)
– Also called leucocytes
– Destroy disease-causing germs

Blood Platelets
– Smaller than red blood cells
– Important to clotting

Plasma
– Fluid part of the blood
– Straw-like in color
– About 90% water and contains proteins, sugar and
oxygen
– Carries food and secretions to cells and carbon
dioxide from cells
Chief functions of Blood

Carries water, oxygen, food, secretions to
cells
 Carries away carbon dioxide and waste
– To be eliminated through lungs, skin, kidneys and
large intestine

Helps equalize body temperature
 Protects from harmful bacteria and infections
– Through white blood cells

Clotting
– Which closes injured minute blood vessels and
prevents excessive blood loss