Functions and Composition of Blood

Transport

Movement of nutrients, gases, hormones, and wastes.

Regulation

Maintaining homeostasis of pH, ions, water, and temperature.

Defence

Protection against fluid loss, pathogens, and toxins.

Haem

UK prefix meaning 'blood'; equivalent to Heme in US.

Blood

Specialized connective tissue with plasma, cells, and platelets.

Plasma

Aqueous component of blood, contains proteins and solutes.

Formed elements

Cells or fragments in blood for various functions.

Red Blood Cells (RBCs)

Erythrocytes responsible for oxygen transport.

White Blood Cells (WBCs)

Leukocytes involved in immune response.

Platelets

Cell fragments aiding in blood clotting.

Total blood volume (male)

5-6 liters in adult males.

Total blood volume (female)

4-5 liters in adult non-pregnant females.

Complete Blood Count (CBC)

Measures formed elements and RBC health.

Mean Corpuscular Hemoglobin (MCH)

Measure of average hemoglobin per RBC.

Mean Corpuscular Volume (MCV)

Measure of average RBC size.

Haematocrit

Percentage of RBCs in whole blood.

Haemostasis

Processes to limit or halt blood loss.

Clotting

Major part of haemostasis involving fibrin formation.

Vascular phase

Fastest phase of haemostasis with vascular spasm.

Platelet phase

Platelets aggregate to plug broken vessels.

Coagulation phase

Fibrin mesh forms around platelets to create clot.

Fibrin

Insoluble protein forming the structure of clots.

Fibrinolysis

Process of dissolving clots after vessel repair.

Erythropoietin (EPO)

Hormone stimulating RBC production in response to hypoxia.

Megakaryocytes

Cells producing platelets in the bone marrow.

RBC lifespan

Approximately 4 months before recycling.

Iron recycling

Recycling of Fe2+ from degraded RBCs.

Intracellular fluid (ICF)

Fluid within cells, comprising 18% of body fluid.

Interstitial fluid (ISF)

Fluid between cells, facilitating nutrient exchange.

Extracellular fluid (ECF)

Fluid outside cells, including plasma and ISF.