ANAT LEC Ch.5 (w/Quiz 2 Questions)

Compact Bone

Covered in PERIOSTEUM (connective tissue)

At the joints

Periosteum is complete everywhere except

LONG BONE Characteristics

• Compact bone covers the outer layer

• thickness varies (thicker=more stress)

• 2 ends

• Osteons are PARALLEL to long axis of bone

Periosteum

Covers the OUTER surface

Periosteum Characteristics

• Protects bone from tissues

• Bone growth/repair

Endosteum Characteristics

• found WITHIN bone lining (medullary cavity)

• incomplete layer= one cell layer thick

• Osteoprogenitor cells

• lines inner of central/perforating canals

• Active during bone GROWTH (and repair kinda)

Mesenchyme and Cartilage

Embryonic development bone replaces BOTH

Ossification

Replacement of tissue with bone

Calcification

Deposition of CALCIUM SALTS in tissue

Two forms of Ossification

Intramembranous & Endochondral Ossification

Epiphyseal Closure

Stops bone growth (Hormones also determine growth b/w sexes)

Appositional Bone Growth

• Bones continue to grow

• Stem cells → Osteoblasts → +ADD bone matrix

Sets of blood vessels that develop in long bones

• Nutrient Artery & Vein

• Metaphyseal vessels (supply blood in bone)

• Epiphyseal vessels (supply osseus tissue & medullary cavity)

• Periosteal vessels (Supply superficial osteons of shaft)

Factors that Regulate Bone Growth

Minerals, Vitamin A & C & D, Calcitriol, and Parathyroid Hormones

OsteoBLAST Activity

Vitamin A stimulates

Collagen synthesis and Osteoblast differentiation

Vitamin C is required for

Bone growth occurs

When osteoBLAST activity OUTNUMBERS osteoCLAST activity…

1/5

How much of the skeletal structure is replaced each year

206

Human Skeleton has around ____ Bones

• sutural

• pneumatized

• short

• long

• irregular

• flat

• sesamoid

7 groups/types of bones

Osteocyte

Mature bone cells that “live“ in pits called Lacunae

Stratum Granulosum

Layer of skin that produces a substance that prevents water loss and is considered last “living“ skin layer

OsteoCLASTS

• Bone cells that secrete acid & enzymes

• Responsible for Osteolysis

Spongy Bone

Bone arranged into parallel structs/plates called trabeculae

Stratum Lucidum

Thin skin lacks the ____ layer

Sutural Bones

Small, Flat bones that are found between the skull bones are ____

Epiphyseal Plate

The “end cap“ of a bone that “closes“ when bone growth stops

Ans. Appositional Growth

Q. Once the length of bone is set it continues to grow

2/3

Calcium Phosphate accounts for ____ of bone weight

Bone to resist compression

Calcium HYDROXIDE reacts with → Calcium PHOSPHATE it forms Hydroxyapatite crystals that allow ______

Canaliculi

_____ radiate thru the matrix interconnecting the LACUNAE

OsteoBLAST Characteristics

• CUBOIDAL cell

• Found in single layer in inner/outer surface of bone

• Produce bone (Osteogenesis)