Functions of Blood Transportation of oxygen and carbon dioxide Transportation of nutrients and waste Maintenance of body temperature Circulation of hormones These red blood cells function in oxygen transport

Physical Characteristics of Blood Adult ♂ contains 5-6L Adult ♀ contains 4-5L 55% is liquid – called plasma 45% is blood cells – together, considered a tissue 5 times as viscous as water –Is it more or less resistant to flow than water? –What accounts for its viscosity? Color ranges from scarlet (oxygenated blood) to a deep red – looks blue from surface (deoxygenated blood).

Whole Blood Plasma (55%) Formed Elements (45%) 1.Water (92%) 2.Plasma Proteins (7%) 3.Other Solutes (1%) 1.Red Blood Cells (99.9%) 2.Platelets 3.White Blood Cells (0.1%)

Plasma Fluid medium for transport – like a river Contains dissolved proteins –Blood clotting proteins –Proteins for antibodies

Red Blood Cells (erythrocytes) Contain hemoglobin – binds to O 2 No nucleus – allows more room for O 2 transport Each RBC is a biconcave disc – why? Short life span (120 days) – due to wear and tear

White Blood Cells (leukocytes) Protects against pathogens Much fewer than RBC’s Several types –Macrophages –Produce antibodies –Memory cells Contain large nucleus Pus = WBC fragments + dead microorganisms

Platelets Flattened disk-like cell fragments Initiate blood clotting Become activated when ruptured due to a sharp edge such as a cut The rupture initiates a chain reaction that results in a blood clot (mesh of protein fibres and trapped RBC’s)

Destroys Type B Destroys Type A Destroys Type A & B Destroys neither A or B

The universal donor The universal acceptor

Comparison of Veins and Arteries ARTERIES FUNCTION: CARRY BLOOD AWAY FROM THE HEART CHARACTERISTICS: VERY THICK, MUSCULAR WALLS VERY HIGH BLOOD PRESSURE CARRIES OXYGENATED BLOOD AWAY FROM HEART (WITH 1 EXCEPTION) EXAMPLES – CORONARY, AORTA, CAROTID, FEMORAL

VEINS FUNCTION: AFTER BLOOD MOVES THROUGH THE ARTERIES IT ENTERS LARGER BLOOD VESSELS CALLED VEINS, WHICH CARRY BLOOD BACK TO THE HEART. CHARACTERISTICS: THINNER WALLS WITH LESS MUSCLE HAVE VALVES (WHY?) CARRIES DEOXYGENATED BLOOD (1 EXCEPTION) EXAMPLES – VENA CAVA, JUGULAR, LOCATION – NEAR MUSCLES (WHY?)

Structure of Blood Vessels

Capillary Structure

Artherosclerosis Fat droplets can stick together to form large obstructions in blood vessels. Calcium & other minerals deposit onto the lipid causing it to harden.

VEINS

VERICOSE VEINS