2. The Three Parts
• Heart
– 4 chambers
– Made of cardiac muscle
– Keeps oxygenated blood separate from
oxygen poor blood
• Blood Vessels
– Capillaries, Veins, Arteries
– Most are surrounded by smooth muscle
• Blood
– Red Blood Cells (RBC), White Blood Cells
(WBC), Platelets
3. Blood
• Human Body contains 4 to 6 liters of
blood (8% of total mass)
• 45% Solids (RBC, WBC & Platelets)
• 55% Plasma (90 – 92% water,
dissolved nutrients, some proteins)
• What color is your blood?
– Dark Red – Lacking oxygen
– Bright Red – Full of oxygen
4. RBC
• Red Blood Cells
– Job is to carry oxygen to cells and carbon dioxide
away from the cells
– Hemoglobin is the molecule within the cell that
actually carries the oxygen & CO2
– Hemoglobin is mostly made of IRON
– RBC are saucer shaped, looks like a donut with
skin on it
– Fairly small and many of them
– Made in the red bone marrow
– Are around for about 120 days, then taken out by
the liver and spleen
5. WBC
• White Blood Cells
– Larger than red blood cells & a lot less of
them
– Include macrophages, B cells & T cells
– Job is to fight off invaders such as bacteria,
virus & fungus
– Made in the bone marrow
– Can move out of the blood vessels into the
tissues & lymphatic system
6. Platelets
• Platelets
– Clumps up to form clots
– Helps stop bleeding
– Just fragments of cells
– Also formed in the bone marrow
7. Blood Vessels
• Carries blood around the body
• Three main types:
– Arteries
– Veins
– Capillaries
8. Arteries
• Large vessels
• Carry blood away from the heart
• Mostly carries oxygen rich blood, except ONE
– The exception is the Pulmonary Artery
• They have thick walls to handle all of the
pressure produced by the heart
• All arteries branch off of the AORTA, the big
U-Shaped vessel coming out of the heart.
• The first arteries off of the AORTA are the
CORONARY arteries (they feed the heart)
• The second arteries that branch off are the
CAROTID arteries (they feed the brain)
9. Veins
• Large vessels
• Carries oxygen poor blood toward the heart,
except ONE
– The pulmonary vein
• Thinner walls than the arteries
• Don’t have the direct pressure from the heart
• Have to fight the effects of gravity
• Use one way valves to keep the from flowing
backwards
10. Capillaries
• Small & Thin
• Only one blood cell can fit through at a
time
• One cell layer thick
• Allows for the exchange of oxygen &
carbon dioxide & all nutrients and waste
products
11. Heart
• Muscle is covered inside by a layer of
smooth tissue called epithelium
• The heart has four chambers: 2 atrium
& 2 Ventricles
• The atriums receive blood coming in
• The ventricles pump blood out
• Pacemaker for the heart is found in the
right atrium
