Skeletal System

Parallel Lamellae

Bone Matrix. Osteocytes between lamellae. Canailculi radiate from lacunae

Perichondrium

Dense, irregular CT. Covers cartilage and helps it maintain its shape.

Medullary Cavity

Hollow, usually cylindrical space within the diaphysis. Contains red and yellow bone marrow.

Axial Skeleton

Skull bones, ossicles of middle ear hyboid, ribs, sternum vertebral column.

Ligaments

Anchor bone to bone.

Tendons

Anchor muscle to bone.

Vascularized

Apart of blood supply and innervation of bone. Vessels that enter the periosteum

Peroforating Canals

Blood vessels and nerves travel through. (Volkmann's canal)

Storage of the Skeletal System

Bone stores the body's reserve of calcium and phosphate. (calcium is essential for muscle contraction, blood clotting and nerve impulse transmission) and (phosphate is ATP utilization). Lipid is stored in yellow bone marrow of adult bones.

Movement of the Skeletal System

Bones serve as attachment sites for skeletal muscles, tissues, some organs. Also acts as a system of levers by altering directions and magnitude of forces.

Interstitual Lamellae

Compact bone between Osteons, Resorbed osteons, no central canal.

Endosteum

Covers all internal surfaces of bone within medullary cavity. Contains osteoprogenitor cells, osteoblasts, and osteoclasts.

Central Canal of an Osteon

Cylindrical channel at center of osteon and parallel to it.

Zone of Disposition

Demonstrates the area where the chondrocytes die and are replaced by blood vessels and osteoblasts, which then form the final trabeculae and osteoclasts that refine the distal contours of the medullary chamber.

Calcification

Deposition of the hydroxyapatite crystals.

Parts of the Long Bone

Diaphysis, epiphysis, epiphyseal plate, metaphysis, medullary cavity, peritoneum and endosteum

Irregular Bones

Elaborate, sometimes complex shapes.

Diaphysis

Elongated, usually cylindrical shaft located within compact bone with thin spicules of spongy bone extending inward.

Flat Bones

Flat, thin surfaces, may be slightly curved. (Top of skull, scapulae, sternum, ribs)

Osteoblasts

Form from Osteoprogenitor cells. Synthesize and secrete osteoid. Turns into osteocytes.

Chondrocytes

Have lacunae, maintain the matrix and chondroblasts are encasted within the matrix.

Red Bone Marrow

Hemopoietic, Reticular CT, and fat. IN CHILDREN- located in Spongy Bone. IN ADULTS: located ONLY in areas of the axial skeleton.

Osteoid

Initial semisolid organic form of bone matrix.

Epiphyseal Plate

It is a hyaline cartilage located in the metaphysis. It is the part of the long bone where new bone growth takes place.

Periosteum

It is a tough sheath around the outer surface of the bone. It serves as protection as well as a channel for the blood supply and nutrients for bone tissue. It is attached to the bone by numerous collagen fibers.

Epiphysis

Knobby region at each end of the bone. (Proximal and Distal). Contains Articular cartilage (Covers joint surface).

Osteoclasts

Large, multinuclear, phagocyte cells. Involved in bone resorption.

Short Bones

Length nearly equal to width. ( carpal bones, tarsals, sesamoid bones)

Spongy Bone

Located internal to compact bone, porous. 20% of bone mass.

Osteocytes

Mature bone cells from derived from Osteoblasts. Detect mechanical stress on bone.

Zone of Calcification

Mineralization of the cartilaginous walls between lacunae provides a temporary framework in the______ by which the final stages of ossification will take place.

Long Bone

Most common bone shape and greater in length than width

Hyaline Cartilage

Most common in the body and grows within growth plates. Connects ribs to sternum and covers end of some bones.

Trabeculae

Narrow rods and plates of bones. Resistance to stress.

Zone of Cell Proliferation

Nearer to the medullary cavity, the ______ is marked by an expansive production of chondrocytes that align in rows in order to replenish those undergoing calcification.

Appositional Growth of Cartilage

Occurs on cartilage's outside edge.

Intersitutial Growth of Cartilage

Occurs within internal regions of cartilage.

Decreases Blood Calcium

Osteoblastic activity, increased use of sunblock, calitonin

Increases Blood Calcium

Osteoclasic activity, caltricol, parathyroid hormone, increased bone resorption

Organic

Osteoid produced by osteoblasts contains collagen protein and semisolid ground substance of proteoglycans and glycoproteins. (Flexible)

Chondroblasts

Produce cartilage matrix

Yellow Bone Marrow

Product of red bone marrow degeneration as children mature. Fatty Substance

Hemopoiesis

Production of blood cells. Occurs in red bone marrow Connective tissue. Stems cells form blood cells and platelets.

Support and Protection of the Skeletal System

Provides structural support and framework for the body. Protects the heart and lungs (rib cage), the brain (cranial bones), the spinal cord (vertebrae) and the urinary and reproductive organs along with terminal end of GI tract (pelvis).

Metaphysis

Region of mature bone between the diaphysis and epiphysis. Ossifies during childhood.

Circumferential Lamellae

Rings of Bone

Concentric Lamellae

Rings of bone CT, surrounding the central canal.

Inorganic

Salt, Crystals and Calcium Phosphate. Forms crystals (hydroxyapatite). (Strong)

Appendicular Skeleton

Shoulder, upper limbs, pelvic girdle, and lower limbs.

Nutrient Foramen

Small opening or hole in bone.

Osteoprogenitor Cells

Stem Cells derived from mesenchyme. Matures to become an Osteoblast. (Located in periosteum and endosteum)

Zone of Hypertrophy

The next layer is the______ where the existing, columnar chondrocytes enlarge and thus force the separations between lacunae to become very thin

Canailculi

Tiny, interconnecting channels within bone CT. Allow exchange of nutrients,minerals, gases, and wastes between blood vessels and osteocytes.

Ossification

To turn into bone or bony tissue.

Compact Bone

White, smooth solid dense connective tissue. 80% of bone mass.

Resorption Lacuna

a groove or cavity usually containing osteoclasts that occurs in bone which is undergoing reabsorption.

Fibrocartilage

weight-bearing cartilage that withstands compression. Located in the invertebral discs, pubic symphasis, pads in knees.