Ch.6 Bone tissue + lab 7

Functions of the Skeletal System

Support, Protection, Movement, Mineral storage (calcium and phosphorous), Hematopoiesis (blood cell formation)

Hematopoiesis

The process of blood cell formation, occurring in red marrow.

Bone Cells

Includes osteogenic cells, osteoblasts, osteocytes, and osteoclasts.

Osteoblasts

Bone-forming cells that lay down bone matrix and collagen fibers.

Compact Bone

Contains bone lamellae, osteocytes, lacunae, canaliculi, central canals, and perforating canals.

Spongy Bone

Composed of trabeculae containing osteocytes and filled with red marrow.

Ossification

The process of bone formation, including intramembranous and endochondral ossification.

Intramembranous Ossification

Bone develops from mesenchyme, forming flat bones such as the skull.

Endochondral Ossification

Bone replaces hyaline cartilage, forming all other bones.

Epiphyseal Plate

Growth plate where longitudinal growth occurs in long bones.

Bone Remodeling

The process of bone resorption and formation, influenced by mechanical stress, hormones, and diet.

Vitamin D

Facilitates calcium absorption and is synthesized in the liver and kidneys.

Calcium Homeostasis in Bones

Regulated by parathyroid hormone and calcitonin to maintain blood calcium levels.

Osteoporosis

A condition characterized by decreased bone density, leading to increased fracture risk.

Fracture Repair Process

Consists of hematoma formation, callus formation, cartilage replacement with bone, and remodeling.

Canaliculi

Small channels in compact bone that allow communication between osteocytes.

Yellow Marrow

A type of bone marrow primarily composed of adipose tissue, serving as an energy reserve.

Red Marrow

Bone marrow responsible for hematopoiesis, producing red blood cells, white blood cells, and platelets.

Osteogenic Cells

Stem cells in the bone that differentiate into osteoblasts and are involved in bone formation.

Osteocytes

Mature bone cells that maintain bone tissue and communicate with other bone cells through canaliculi.

Osteoclasts

Cells responsible for bone resorption, breaking down bone tissue to release minerals into the bloodstream.

Periosteum

A dense layer of vascular connective tissue enveloping the bones, aiding in attachment and growth.

Endosteum

Thin connective tissue lining the medullary cavity, involved in bone growth and remodeling.

Epiphysis

The end part of a long bone, where growth occurs and which articulates with adjacent bones.

Articular Cartilage

Smooth cartilage covering the ends of bones at joints, reducing friction and absorbing shock.

Epiphyseal Line

The remnant of the epiphyseal plate, indicating where growth in length has ceased.

Diaphysis

The long shaft of a long bone, providing structural support.

Medullary Cavity

The central cavity of bone shafts, housing yellow or red bone marrow.

Bone Marrow

Soft tissue inside bones, involved in the production of blood cells.

Composition of Bone

Primarily made of organic components (collagen, proteins) and inorganic components (calcium phosphate).

Inorganic Components

Examples include hydroxyapatite (calcium phosphate) and various minerals providing strength.

Intramembranous Ossification Process

Bone develops directly from mesenchyme, forming flat bones like the skull.

Flat Bones

Composed of two layers of compact bone surrounding a layer of spongy bone; examples include skull bones.

Endochondral Ossification Process

Process where bone forms by replacing hyaline cartilage, occurring in long bones.

Longitudinal (Interstitial) Growth

Growth in length that occurs at the epiphyseal plates in long bones.

Appositional Growth

Growth in diameter or thickness of bone, occurring on the outer surface.

Parathyroid Hormone

Hormone that regulates calcium levels in the blood by promoting bone resorption.

Calcitonin

Hormone that lowers blood calcium levels by inhibiting osteoclast activity and promoting calcium deposition in bones.

Appendicular Skeleton

Composed of the shoulder girdle, upper limbs, pelvic girdle, and lower limbs, involved in movement.

Compact Bone Structure

Features bone lamellae, osteocytes, lacunae, canaliculi, and central canals that contain blood vessels and nerves.

Spongy Bone Composition

Composed of trabeculae containing osteocytes, with red marrow filling the spaces, found in epiphyses, ribs, vertebrae, and skull.

Types of Bone Marrow in Adults

Red bone marrow found in flat bones and epiphyses of femur and humerus; yellow bone marrow located in the medullary cavity of long bones.

Bone Shapes

Includes long, short, flat, irregular, and sesamoid bones.

Epiphyseal Plate

Visible in a growing bone; it progresses to an epiphyseal line in mature bones.

Epiphyseal Line

The remnants of the epiphyseal plate seen in mature bones.

Bone Lamellae

Thin layers of bone tissue that are arranged in a concentric circle around central canals, contributing to the structure of compact bone.

Osteocytes

Mature bone cells that are embedded within the bone matrix and play a critical role in maintaining bone tissue.

Lacuna

Small spaces within the bone matrix that house osteocytes.

Canaliculi

Microscopic canals that connect lacunae, allowing communication and nutrient transport between osteocytes.

Central Canals

Hollow tubes within the compact bone that contain blood vessels and nerves, facilitating blood flow and nerve supply to the bone.

Perforating Canals

Channels in bone that allow blood vessels and nerves to travel from the outside of the bone to the central canals.

Osteon

The basic structural unit of compact bone