Skeletal System: Bone Structure and Function Study Guide

Skeletal System Components

Includes bone and cartilage.

Types of Bone Tissue

Compact and spongy bone tissue.

Functions of Skeletal System

Support, protection, movement, hematopoiesis, mineral storage.

Hematopoiesis

Blood cell formation in bone marrow.

Long Bones

Examples include femur and humerus.

Short Bones

Examples include carpals and tarsals.

Flat Bones

Examples include skull and sternum.

Irregular Bones

Examples include vertebrae and pelvis.

Parts of Long Bones

Includes diaphysis, metaphysis, epiphysis.

Medullary Cavity

Hollow space in long bones for marrow.

Articular Cartilage

Covers bone ends at joints.

Epiphyseal Line

Remnant of growth plate in adults.

Periosteum

Connective tissue covering bone; two layers.

Outer Fibrous Layer

Contains perforating fibers for attachment.

Inner Cellular Layer

Contains osteoblasts and osteoclasts.

Endosteum

Thin membrane lining medullary cavity.

Red Bone Marrow

Produces blood cells; found in certain bones.

Yellow Bone Marrow

Stores fat; found in long bones.

Bone Matrix

Composed of organic osteoid and inorganic minerals.

Osteoid

Organic component secreted by osteoblasts.

Calcium Storage Forms

Includes calcium phosphate and hydroxyapatite.

Bone Cells

Includes osteoprogenitor, osteoblasts, osteocytes, osteoclasts.

Bone Formation Process

Involves osteoid formation and calcification.

Bone Resorption

Process of breaking down bone tissue.

Spongy Bone

Less dense, contains trabeculae.

Compact Bone

Dense, forms outer layer of bones.

Haversian System

Structural unit of compact bone.

Trabeculae

Supportive structures in spongy bone.

Hyaline Cartilage Histology

Contains chondroblasts and chondrocytes.

Perichondrium

Connective tissue surrounding cartilage.

Endochondral Bone Formation

Cartilage model replaced by bone.

Intramembranous Bone Formation

Bone develops directly from mesenchyme.

Interstitial Growth

Lengthening of long bones.

Appositional Growth

Widening of long bones.

Bone Remodeling

Ongoing replacement of old bone tissue.

Bone remodeling

Process of bone renewal and reshaping.

Cells in bone remodeling

Osteoblasts, osteoclasts, and osteocytes involved.

Mechanical stress

Stimulus for bone remodeling and adaptation.

Hormones influencing bone growth

Regulators include growth hormone, estrogen, and progesterone.

Growth hormone

Stimulates bone growth and increases height.

Estrogen

Promotes bone density and growth in females.

Progesterone

Supports bone health during pregnancy.

Calcium concentration

Essential for muscle contraction and nerve function.

Parathyroid hormone (PTH)

Primary regulator of blood calcium levels.

Calcitriol

Active form of vitamin D, raises calcium levels.

Calcitonin

Lowers blood calcium levels, less significant than PTH.

Vitamin D production

Sunlight converts cholesterol to vitamin D.

Gastrointestinal calcium absorption

Increased by vitamin D for higher blood calcium.

Renal calcium reabsorption

Vitamin D enhances kidney's calcium retention.

Bone calcium mobilization

Vitamin D releases calcium from bones.

Aging effects on bone

Leads to decreased density and increased fragility.

Rickets

Vitamin D deficiency causing bone weakness in children.

Osteoporosis

Condition of weak bones due to density loss.

Bone fracture

Break in bone integrity due to stress.

Common bone fractures

Include simple, compound, and stress fractures.

Bone healing process

Involves inflammation, repair, and remodeling phases.

Compact bone

Dense bone tissue, makes up 80% of mass.

Spongy bone

Porous bone tissue, contains marrow, 20% of mass.

Hyaline cartilage

Connects ribs to sternum and covers bone ends.

Fibrocartilage

Provides cushioning in joints and discs.

Ligaments

Connect bone to bone, providing stability.

Tendons

Connect muscle to bone, enabling movement.

Hematopoiesis

Process of blood cell production in bones.

Diaphysis

Elongated cylindrical shaft of long bones.

Epiphysis

Knobby ends of long bones.

Medullary Cavity

Hollow space in diaphysis containing marrow.

Compact Bone

Dense outer layer providing strength to bones.

Spongy Bone

Internal bone structure that resists stress.

Articular Cartilage

Hyaline cartilage covering joint surfaces.

Metaphysis

Region between diaphysis and epiphysis in mature bones.

Epiphyseal Plate

Growth plate in developing long bones.

Periosteum

Outer sheath covering bones, contains blood vessels.

Endosteum

Covers internal surfaces of bone, aids growth.

Osteoprogenitor Cells

Stem cells that develop into bone cells.

Osteoblasts

Cells responsible for bone formation.

Osteoclasts

Cells that break down bone tissue.

Diploe

Spongy bone found in flat bones of skull.

Nutrient Foramen

Opening for blood vessels entering bone.

Long Bones

Bones with elongated shape, like limbs.

Short Bones

Bones with nearly equal length and width.

Flat Bones

Thin bones that protect soft tissues.

Irregular Bones

Bones with complex shapes, like hip bones.

Calcium Storage

Bones store calcium for physiological functions.

Phosphate Storage

Bones act as a reservoir for phosphate.

Bone Vascularization

Bones have a rich blood supply.

Circumferential Growth

Growth around the circumference of bones.

Nutrient Artery

Artery supplying nutrients to bone.

Nutrient Vein

Vein draining waste from bone.

Red Bone Marrow

Forms blood cells in spongy bone.

Yellow Bone Marrow

Fatty substance formed from red marrow degeneration.

Bone Marrow Transplant

Transplantation for destroyed or dysfunctional marrow.

Osteoprogenitor Cells

Stem cells developing into osteoblasts.

Osteoblasts

Cells synthesizing and secreting bone matrix.

Osteocytes

Mature bone cells maintaining bone matrix.

Osteoclasts

Multinuclear cells involved in bone resorption.

Osteoid

Organic matrix composed of collagen and proteoglycans.

Hydroxyapatite Crystals

Calcium phosphate crystals hardening bone matrix.

Bone Matrix

Composed of organic and inorganic components.

Bone Resorption

Process of bone tissue breakdown by osteoclasts.

Calcification

Mineralization of osteoid with hydroxyapatite crystals.