Hematopoiesis Overview

Hematopoiesis Overview

Functions of Blood:

• Transport: Carries oxygen, nutrients, and waste products throughout the body.

• Protection: Defends the body against disease-causing agents (pathogens).

• Regulation: Maintains homeostasis (a stable internal environment) by regulating temperature, pH, and fluid balance.

Composition and Properties of Blood:

• Specific Gravity:

• Whole blood: 1.05 – 1.06

• Plasma: 1.03

• Blood cells: 1.10

• Specific gravity is influenced by the concentration of proteins, blood cells, and other solutes in plasma.

• Viscosity:

• Blood: 3.8 – 4.5 (relative to water)

• Plasma: 1.6 – 1.7 (relative to water)

• Blood viscosity is determined by protein concentration and the number of blood cells. Increased viscosity due to elevated blood cells or protein levels can contribute to heart failure and hypertension.

• Osmotic Pressure: Approximately 7.5 atm, primarily due to dissolved sodium chloride (NaCl) and a smaller contribution from dissolved proteins.

• pH: 7.39 (slightly alkaline)

• Suffocation, shock: pH shifts toward acidic.

• Rapid breathing: pH shifts toward alkaline.

• Volume: 7-9% of body weight (approximately 1/13 kg).

• Blood Volume: 75 ml/kg (in adults).

Percentage of Blood Cells and Plasma:

• Determined by centrifugation in a hematocrit tube.

• Blood cells (hematocrit): 46%.

• Plasma: 54%.

• The ratio of blood cells to plasma roughly matches the ratio of red blood cells to plasma because the layer containing white blood cells and platelets is very thin (approximately 1%).

• Normal hematocrit (Hct): 44-48%.

Plasma:

• Pale yellow liquid.

• Water: 91%

• Proteins: 7%

• Electrolytes, nutrients, waste products, hormones, enzymes: 2%

Key Components of Plasma:

• Electrolytes:

• Compose 0.75% of plasma.

• Include anions and cations.

• Sodium (Na) and chloride (Cl) ions: Contribute to osmotic pressure, regulating water distribution between intracellular and extracellular compartments.

• Potassium (K) ions: Essential for nerve impulses, muscle contraction, particularly in the heart.

• Calcium (Ca) ions: Contribute to bone and tooth formation, blood clotting, and nerve-muscle excitation.

• Phosphates: Involved in electrolyte balance within red blood cells and acid-base regulation.

• Organic Compounds:

• Plasma proteins

• Lipids

• Carbohydrates

Roles of Specific Plasma Components:

• Zinc (Zn): Required for insulin function.

• Chloride (Cl): Required for amylase activity.

• Iron (Fe): Essential for red blood cell production.

• Iodine (I): Needed for thyroid hormone synthesis.

Important Notes:

• Blood pH depends on the concentration of electrolytes in plasma, primarily H+ and HCO3- (bicarbonate).

• Plasma component concentrations can vary depending on age, gender, health status, and other factors.

• This information provides a basic overview of the hematopoietic system. For a more comprehensive understanding, consult reliable medical resources.