C.A.B.M. | 2024
1
Blood
Overview of Blood
• Functions:
o Transports nutrients, wastes, hormones,
and body heat.
• Blood is the only fluid connective tissue in the
body.
Components of Blood
1. Formed Elements:
o Living cells (erythrocytes, leukocytes,
and platelets).
2. Plasma:
o Non-living fluid matrix.
When Blood is Separated:
1. Erythrocytes:
o Sink to the bottom (45% of blood;
percentage known as the hematocrit).
2. Buffy Coat (blood separated):
o Thin, whitish layer between erythrocytes
and plasma.
o Contains leukocytes and platelets (less
than 1% of blood).
3. Plasma:
o Rises to the top (55% of blood).
Physical Characteristics of Blood
• Appearance:
o Sticky, opaque fluid; heavier and thicker
than water.
o Oxygen-rich blood: scarlet red;
oxygen-poor blood: dull red or purple.
• Taste and pH:
o Metallic, salty taste; slightly alkaline
(pH 7.35–7.45).
• Temperature and Volume:
o Temperature: 38°C (100.4°F).
o Volume: ~5–6 liters in adults (8% of
body weight).
Plasma
• Composition:
o 90% water, straw-colored.
o Dissolved substances: nutrients, salts
(electrolytes), respiratory gases,
hormones, plasma proteins, waste
products.
• Plasma Proteins:
o Most abundant solutes in plasma
o Produced by the liver.
o Types:
▪ Albumin: Maintains osmotic
pressure, acts as a blood buffer.
▪ Clotting Proteins: Assist in
blood vessel injury repair.
▪ Antibodies: Protect against
pathogens.
• Functions:
o Distributes body heat.
o Maintains pH through respiratory and
urinary systems.
• Blood composition varies as cells exchange
substances with the blood
o Liver makes more proteins when levels
drop
o Respiratory and urinary systems
restore blood pH to normal when blood
becomes too acidic or alkaline
Formed Elements
1. Erythrocytes (Red Blood Cells - RBCs):
o Function: Carry oxygen.
