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 O2

• No nucleus – allows more room for O2 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 ArteriesARTERIES

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

VERICOSE VEINS