Four types of connective tissue
Cartilage, Bone, Bone Marrow, Periosteum
Tissue that makes up MOST of the skeleton
osseous(bone) tissue
Functions of bone are
movement, protection, support, mineral storage, hemopoeisis, energy storage
Movement
provides leverage for muscle contraction
Protection
protects internal organs from physical injury
Support
supports soft tissue and provides a point of attachment for skeletal muscles
Mineral storage
Calcium and phosphate in bone is available when needed elsewhere in
the body
Hemopoeisis
Blood cell production occurs in red bone barrow
Energy storage
Yellow bone marrow contain lipids, an important source of energy
2 Divisions of the skeletal system
Axial & Appendicular portion
Axial portion
80 bones that are arranged along the longitudinal axis of the body
Appendicular portion
126 bones (mostly right & left sides)
ex. appendages, shoulder, pelvic(hip) bones
Examples of Appendages
Arms, legs, hands feet
Examples of shoulder
clavicle, scapula
Examples of pelvic(hip)
os coxae
Classifcation of bones
long bones, short bones, flat bones, irregular bones, suture bones,
sesamoid bones
Long bones
longer than they are wide
Example of long bone
Femur
Longest & heavies bone in the body
Femur
Short bones
cube shaped
Example of short bones
Tarsals in ankle
Flat bone examples
ribs, sternum, scapula, cranium
Irregular bones are
complex in shape
Irregular bone example
vertebrae
Suture bones are
complex in shape
Example of suture bones
found in cranium
ex. coronal suture
Sesamoid bones are
small bones embedded in tendon/extra bones
Example of sesamoid bone
Patella(knee cap)
Proximal Epiphysis
End of a long bone which is spongy(cancellous) bone arranging in a
latticework of thin plates called TRABECULAE.
Diaphysis
shaft of long bone which is compact(dense) bone tissue
Distal Epiphysis
distal end of long bone which the same structure as the proximal epiphysis
Epiphyses are usually ____than the long bone
larger
Metaphysis
area where the diaphysis joins the epiphysis. Includes the epiphyseal
plate in growing long bones; a layer of hyaline cartilage that allows
the diaphysis to grow in length
Medullary cavity
where yellow bone marrow is found
Articular cartilage
found where two bones come together(joint)
function of articular cartilage
reduce friction as joint and absorb shock
Periosteum
thin layer of dense CT membrane around the surface of the bone
function of periosteum
repair and nutrition of the bone. tendons and ligaments attach.
OUTSIDE OF BONES
Endosteum
membrane that lines the medullary cavity of the bone. Contains
osteoprogenitor cells and osteoclasts.
Four main types of cells in bone tissue
osteoprogenitor, osteoblast, osteocyte, osteoclast
Osteoprogenitor
found in the inner portion of the periosteum, in the endosteum and
canals in bone that contain blood vessels.
Function of osteoprogenitor
undergo mitosis and become osteoblasts(immature)
Osteoblasts
cells that form bone tissue. secrete collagen and matrix which
calcifies to build bone tissue.
Osteocyte
mature bone cells.
Maintain bone tissue by exchanging nutrients and wastes with the blood
Osteoclast
cell that's important in the development, growth, maintenance, and
repair of one.
Function of osteoclast
resorption of bone (breaking down of bone tissue)
Living bone is
bone cells and collagen fibers
non living bone=
hydroxapatite
calcium, phosphorus, and chemical components of the matrix
Bones become more _____ as we age
brittle
Bone remodeling
continuous ongoing replacement of old bone tissue with new bone tissue
Osteoblasts are constantly ___
forming new bone tissue
Osteoclasts are constantly_____
destroying old bone tissue
Bone is a major storage area for _____
calcium
Calcium is important for
heart, nerve, enzyme, and blood physiology
Bone vs blood calcium levels are regulated by
Parathyroid glands and throid gland
Parathyroid gland secretes
PTH(parathyroid hormone)
Thyroid gland secretes
hormone calcitonin
If blood calcium levels are HIGH ____
calcitonin is released by the thyroid gland and osteoblasts are
stimulated to build more bone. This uses calcium so the blood calcium
levels decrease to normal
If the blood calcium levels are LOW______
PTH is released by the parathyroid gland and osteoclasts are
stimulated to break down bone to release calcium ions and blood
calcium levels increase to normal.
Fracture is
break in bone
4 sequence of events for repair
fracture hematoma, fibrocartilageinous callus, bony callus, remodeling
Fracture hematoma
formation of a blood clot
Fibrocartilaginous callus
organization of the fracture into granulation tissue called procallus
Bony callus
fibrocartilaginous(soft) callus becomes bony(hard) callus
remodeling
restoration of the bone to near original structure and form
Colle's fracture
break in the distal end of the radius
Potts fracture
break in the distal end of the ribia
Most frequently broken bone in the body
Clavicle
Compact(dense bone)
consists of osteons with very little space between them, composes
bone tissue of the diaphysis
Function of compact(dense) bone
protect and support
Spongy(Cancellous) bone
does not contain osteons, consists of trabeculae surrounding many
red-marriw filled spaces, found in short, flat, and irregulkar bones
and in the epiphyses of long bones
Spongy(cancellous) bones function
store red marrow and provide some support
ossification is
bone formation
2 types of bone formation(ossifiossificationcation)
Intramembrane ossification, endochondrial
Intramembranous ossification
occurs within fibrous membranes. Mesencyhaml ceels become
osteoprogenitor cells which then become osteoblasts which secrete bone matrix.
Endochondroial oossification
occurs within a hyaline cartilage model
Primary ossification center of a long bone is in the
Diaphysis
Secondary ossification centers develop in the
Epiphyses, where bone replaces cartilage except for the epiphyseal plate
Epipuseal plate
layer of hyaline cartilage in the metaphysis of growing bone
4 zones(epiphysis to diaphysis)
resting cartilage, proliferating cartilage, hypertrophic(maturing
cartilage), calcified cartilage
Resting cartilage
anchor the epiphyseal plate to the bone of the epiphysis
Prolifterating cartilage
layer of chondrocytes stacked like coins in columns
hypertropic(maturing) cartilage
larger chondrocytes, stacked in columns
Calcified cartilage
only a few cells thick. Calcified matrix; cements epiphyseal plate to
the bone of the diaphysis.
at 20 years of age bones stop growing in length because of
sex steroids (mainly estrogens in male/females) & shut down at
the epiphyseal plate