Lecture 23 BIO 203: Lecture on Bone Physiology, Hematopoiesis, and Hemostasis (copy)

Definition of Bone as Living Tissue

Bone is a living tissue because it contains living cells embedded within a mineralized matrix.

Trabecular Bone vs. Compact Bone

Trabecular bone is spongy and lightweight, found at the ends of long bones. Compact bone is dense and forms the shaft of the bone.

Adaptive Changes in Bone

Bone undergoes reorganizational changes in response to physical stress, such as remodeling trabeculae with increased activity.

Articulating Surfaces Definition

Articulating surfaces are the ends of the bone where cartilage provides a smooth surface for joint function.

Osteoblasts Function

Osteoblasts are bone-building cells that secrete proteins and minerals to form new bone tissue.

Osteoclasts Function

Osteoclasts are cells responsible for the resorption or breakdown of bone.

Osteocytes Definition

Osteocytes are mature osteoblasts residing within the matrix of mature bone.

Commonality between Cartilage and Bone

Both are types of connective tissue with cells dispersed within an extracellular matrix (ECM).

Chondrocytes Role

Chondrocytes are the cartilage cells responsible for producing the cartilage matrix.

Linear Bone Growth Mechanism

Linear bone growth occurs at the epiphyseal plate, driven by Growth Hormone (GH) and involves chondrocyte proliferation.

Gigantism Cause

Gigantism is caused by an anterior pituitary tumor in childhood that overproduces Growth Hormone.

Osteoporosis Definition

Osteoporosis occurs when osteoclast activity exceeds osteoblast activity, leading to fragile bones.

Hematopoiesis Definition

Hematopoiesis is the production of all blood cells occurring in the red bone marrow.

Plasma Components

Plasma, the fluid portion of blood, contains water, vitamins, amino acids, lipids, gases, and proteins.

Mechanisms of Hemostasis

Hemostasis involves vasoconstriction, platelet plug formation, coagulation, and restriction to stop bleeding.

Fibrinolysis Definition

Fibrinolysis is the process of breaking down a blood clot after tissue repair begins.

Therapeutic Use of TPA

TPA can be administered to dissolve pathological clots, such as those formed during heart attacks or strokes.