THE OSSEOUS TISSUE

FUNCTIONS

•         PROVIDE SUPPORT FOR OTHER TISSUES AND PROTECT UNDERLYING TISSUES

•         BONES ARE GOOD FOR STORAGE

•         HEMATOPOIESIS ( form blood cells )

TYPES OF BONE TISSUE

BY THE BONE STRUCTURE WE HAVE:

1. SPONGY BONE -  Lightweight, but able to withstand stress.
2. COMPACT BONE – Very dense and strong, found on the outside of all bones as a protective layer

MICROSCOPIC STRUCTURE OF COMPACT BONE

•         Is organized into individual functional units know as OSTEONS or HARVESIAN SYSTEMS.

•         Each osteon is composed of concentric layers of tissue know as LAMELLAE.

•         OSTEOCYTES maintain the bone matrix and wall themselves off in “caves”. So in bone we have osteocytes in lacunae.

•         Osteocytes get nutrition via a central canal in osteon know as HARVESIAN CANAL, or CENTRAL CANAL. Canals that run perpendicular to Central Canals are know as VOLKMANN’S CANALS. ( This network of blood vessels provides nutrition of bone)

MICROSCOPIC STRUCTURE OF SPONGY BONE

•         Spongy bone does not have osteons, instead spongy bone looks like a sponge, the bony pieces are called TRABECULAE

•         Trabeculae are only a few cell layers thick and houses osteocytes. Blood vessels run throughout spongy bone, and marrow fills space between the bone tissue

OSSEOUS TISSUE is a supporting connective tissue…

1. THE MATRIX IS PARTIALLY “ORGANIC” ( Collagen fibers, and some glycoproteins ) AND PARTIALLY “INOGANIC” ( Mineral salts – CALCIUM  is the most important mineral but we have phosphorus, magnesium, and others )

       And…THE CELLS

•         OSTEOBLASTS

•         OSTEOCYTES

•         STEM CELLS

•         OSTEOCLASTS

THE BALANCE BETWEEN OSTEOBLASTS AND OSTEOCLASTS IS VERY IMPORTANT

OSTEOGENESIS

•         6 WEEKS AFTER FERTILIZATION BEGINS THE OSTEOGENESIS.

•         BONES IS FORMED FROM MESENCHYME ( Embryonic connective tissue )

•         BEFORE OSSIFICATION OCCURS THE SKELETON IS COMPOSED OF FIBROUS CONNECTIVE TISSUE OR CARTILAGE

•         OSSIFICATION OCCURS IN TWO DIFFERENT WAYS DEPENDING ON THE “FORERUNNR” TISSUE

1. INTRAMEMBRANOUS OSSIFICATION

2. ENDOCHONDRAL OSSIFICATION

CLASSIFICATION OF BONES

•         LONG BONES

•         SHORT BONES

•         SESAMOID BONES

•         FLAT BONES

•         IRREGULAR BONES

•         SUTURAL BONES ( Wormian bones )

LONG BONES:

•         GREATER IN LENGTH THAN IN WIDH.

•         THE FEMUR IS THE LARGEST BONE IN THE BODY

SHORT BONES

•         ARE ALMOST AS WIDE AS THEY ARE LONG

•         CUBELIKE

•         TARSAL AND CARPAL BONES

FLAT BONES

•         HAVE THIN AND PARALLEL SURFACES...FLAT!!!

•         SKULL BONES, STERNUM, AND RIBS

•         2 plates of compact bone with a layer of spongy bone inside

IRREGULAR BONES

            SOME OF THE SKULL BONES, VERTEBRAE, HIP BONES

SESAMOID BONES

•         SPECIAL CLASS OF SHORT BONES.

•         THIS BONES ARE EMBEDDED IN TENDONS, USUALLY SMALL, EXCEPT FOR THE PATELLA

SUTURAL BONES

•         OCCUR ALONG SUTURE LINES OF SKULL WHERE THE SUTURE HAS BRANCHED AND SURROUNDED A SMALL PIECE OF BONE

STRUCTURE OF A LONG BONE

•         DIAPHYSIS - The shaft of the long bone

•         EPIPHYSIS – The ends of the long bone

•         METAPHYSIS – Space between diaphysis and epiphysis.

•         MEDULLARY CAVITY – The cavity in diaphysis of long bone, filled with YELLOW MARROW.

•         EPIPHYSEAL PLATE – The area of longitudinal growth.

•         EPIPHYSEAL LINE – The emnant of the epiphyseal plate in mature bones.

•         ARTICULAR CARTILAGE – The top of the epiphysis are covered with hyaline cartilage.

            PERIOSTEUM – Two layered connective tissue membrane which  surrounds the entire bone except for the areas of articulation.                                           The outer layer ( FIBROUS LAYER ) is made of dense irregular connective tissue, the inner layer ( CELLULAR

                                           LAYER ) contains osteoblasts and osteoclasts                       

ENDOSTEUM – A delicate connective tissue membrane which lines the inner bone surfaces ( Marrow cavities )

THERE ARE TWO TYPES OF BONE MARROW:

•         YELLOW MARROW – Adipose tissue found in the diaphysis and parts of the epiphysis in long bones.

•         RED MARROW – Found in epiphysis of some long bones ( Head of the femur and humerus ) and the Diploe of flat bones. Also know as HEMATOPOIETIC TISSUE

THE OSSEOUS TISSUE PART II

SKELETAL TERMINOLOGY

EACH BONE HAS CERTAIN ANATOMICAL FEATURES ON THE SURFACE CALLED BONE MARKINGS OR

SURFACE MARKINGS

ELEVATIONS/PROJECTIONS

•         PROCESS

•         RAMUS

PROCESSES FORMED WHERE TENDONS OR LIGAMENTS ATTACH

•         TROCHANTER

•         TUBEROSITY

•         TUBERCLE

•         CREST

•         LINE

•         SPINE

PROCESSES FORMED FOR ARTICULATION WITH ADJACENT BONES

•         HEAD

•         NECK

•         CONDYLE

•         TROCHLEA

•         FACET

DEPRESSIONS

•         FOSSA

•         SULCUS

OPENINGS

•         FORAMEN

•         CANAL

•         FISSURE

•         SINUS OR ANTRUM

THE SKELETON

•         THE ADULT SKELETAL SYSTEM CONSISTS OF 206 BONES.

•         WE DIVIDE SKELETON INTO AXIAL AND APPENDICULAR DIVISIONS

AXIAL DIVISION INCLUDES

SKULL, VERTEBRAE, STERNUM, 12 PAIRS OF RIBS, AND HYOID BONE 80 BONES

APPENDICULAR DIVISION CONSISTS OF THE

PECTORAL GIRDLES PLUS UPPER LIMBS AND PELVIC GIRDLE PLUS LOWER LIMBS 126 BONES

FRACTURES

THESE ARE THE FOUR MAJOR STEPS IN FRACTURE REPAIR

•         A Hematoma forms at the site of the injury

•         A fibrocartilaginous callus is formed

•         Formation of bone callous

•         Bone remodeling occurs

TYPES OF FRACTURES

•         SPIRAL

•         TRANSVERSE

•         COMMINUTED

•         DISPLACED

•         GREENSTICK

•         EPIPHYSEAL

•         BY COMPRESSION

•         COMPOUND FRACTURE

- Complete the notes with your textbook, with your Martini’s.