Blood Functions and Characteristics

Blood Functions

• Blood is a connective tissue responsible for transportation, regulation, and protection.
• Transportation: Carries oxygen, nutrients, hormones, and waste products.
• Regulation: Balances pH, temperature, and water content.
• Protection: White blood cells fight disease, and platelets aid in blood clotting (hemostasis).

Blood Characteristics

• Amount: Varies by individual size and sex.
• Color: Reddish due to hemoglobin.
• pH: Maintained within a narrow range.
• Viscosity: Thickness or resistance to flow.

Blood Components

• Plasma: Liquid portion, 91% water, containing dissolved substances like nutrients, hormones, and waste products. Plasma proteins play critical roles in clotting, transporting substances and regulating fluid balance.
• Formed elements: Include erythrocytes (red blood cells), leukocytes (white blood cells), and platelets (thrombocytes).

Plasma Functions

• Transportation: Carries essential substances throughout the body.
• pH balance: Maintains a stable blood pH.
• Carries body heat: Transports heat to regulate body temperature.
• Role of liver: Creates numerous plasma proteins.
• Role of muscles: Contribute to blood flow and heat distribution.

Blood Cell Formation

• Blood cells originate from stem cells within the bone marrow.
• Red blood cells (erythrocytes) are formed from a reticulocyte.
• White blood cells (leukocytes) and platelets are also produced by stem cells.

Red Blood Cells (Erythrocytes)

• Structure: Anucleate, biconcave, contain hemoglobin.
• Function: Transport oxygen and carbon dioxide.
• Labs: Hemoglobin levels and hematocrit (Hct) are measured for assessing red blood cell count and function. Ingredients necessary for production include vitamin B12 (extrinsic factor), iron, folic acid, and other vitamins.
• Life cycle: About 120 days, produced and removed by the body continuously.

White Blood Cells (Leukocytes) - Granulocytes and Agranulocytes

• Structure: Contain a nucleus and various internal structures
• Function: Defense and immune responses.
  • Granulocytes: Neutrophils (most abundant), eosinophils (allergic reactions), basophils (secretions).
  • Agranulocytes: Lymphocytes (specific immunity), monocytes (phagocytosis).
• Labs: A white blood cell count is a measure of leukocyte levels.

Platelets (Thrombocytes)

• Structure: Fragments, survive about 7 days, involved in clotting. Platelet count assists with diagnosing issues.
• Function: Blood clotting (hemostasis). 3 steps: vascular spasm, platelet plug formation and chemical clotting.
• Labs: Platelet counts assess function.

Blood Clotting (Hemostasis)

• The goal is to form a blood clot.
• Stage 1: Formation of substances for clotting
• Stage 2: Prothrombin is converted to thrombin, converting fibrinogen to fibrin.
• Stage 3: Fibrin forms a mesh trap that holds RBCs and platelets.

Blood Clot Dissolution (Fibrinolysis)

• Dissolution of a blood clot occurs with the help of the chemical plasmin dissolving fibrin in the blood clot.
• The prevention of blood clots can be aided through smooth endothelium, blood flow, Heparin, natural production by basophils.

Blood Typing and Blood Groups

• Blood type is identified by the presence or absence of antigens (A, B) on red blood cells and corresponding antibodies in the blood plasma.
• Universal donor: O-
• Universal recipient: AB+

This quiz covers the essential functions, characteristics, and components of blood. Topics include transportation, regulation, and protection roles of blood as well as an overview of its components such as plasma and formed elements. Test your understanding of this vital connective tissue and its significance in the body.