AnaPhy Lec 3 Osseous Tissue and Bone Structure

Support, Protection, Leverage, Storage of Minerals, Blood Cell Production

5 Functions of the Skeletal System

Axial and Appendicular

2 Types of Bone Classification according to Location

Flat, Long, Irregular, Sutural, Sesamoid, Short

6 Kinds of Bone Classification according to Shape and Structure

FLISSS

Axial Skeleton

[Bone Classification]
- (80 Bones) Portion of the skeletal system that consists of the skull, rib cage, and vertebral column
- Protect and Support

Appendicular Skeleton

[Bone Classification]
- (126 bones) includes bones of the limbs and the pectoral and pelvic girdles that attach the limbs to the axial skeleton.
- Leverage and movement

Flat Bones

[Bone Classification]
- thin, roughly parallel surfaces.
- muscle attachment and organ protection
- they form the roof of the skull, sternum, the ribs, and the scapulae.
- They provide protection from underlying soft tissues and offer an extensive surface for the attachment of skeletal muscles.

Sutural Bones

[Bone Classification]
-also known as Wormian bones
- they are small, flat, irregularly shaped bones between the flat bones of the skull.
- varies among individuals
- Their borders are like pieces of a jigsaw puzzle, and they range in size from a grain of sand to a quarter.

Long Bones

[Bone Classification]
- are relatively long and slender.
- movement
- found in the arms and legs

Irregular Bones

[Bone Classification]
- have complex shapes with short, flat, notched, or ridged surfaces.
- most bones
- The spinal vertebrae, the bones of the pelvis, and several of the skull bones (mandible for example) are irregular bones.

Sesamoid Bones

[Bone Classification]
- are generally small, flat, and shaped somewhat like a sesame seed.
- small and boxy stabilizers
- They develop inside of tendons and are most commonly located near joints at the knees, the hands, and the feet.
- Everyone has sesamoid patellae, or kneecaps, but individuals vary in the location and abundance of other sesamoid bones. This variation, among others, accounts for disparities in the total number of bones in the skeleton.

Short Bones

[Bone Classification]
- small and boxy. Examples of short bones include bones of the wrist (carpals) and bones of the ankles (tarsals).

206

Average number of Bones in the Human Body

Diaphysis

[Bone Structure]
long tubular shaft that forms the axis of a typical long bone; the walls of the shaft are made primarily of compact bone

Epiphyses

[Bone Structure]
ends of the bones composed primarily of spongy bone, also called trabecular bone. Spongy bone consists of an open network of struts and plates (called trabeculae) that resemble a latticework with red bone marrow filling in the spaces between. The spongy bone is then covered by a thin layer of compact bone and articular cartilage

Compact Bone, Spongy Bone, Trabecular Bone

[Bone Structure]
Walls of the Diaphysis are mostly made out of _____2 words ______ while the Epiphyses is primarily composed of ____2 words_____, which is often called ______2 words______.

Proximal, Distal

[Bone Structure]
The _________ epiphyses is the end closest to the origin of attachment while the __________ epiphysis is the further end.

Metaphysis

[Bone Structure]
a narrow zone that connects the diaphysis to the epiphyses.

Epiphyseal plate

[Bone Structure]
a thin layer of hyaline cartilage more commonly called the growth plate, is important for growth in the length of bones.

Medullary Cavity

[Bone Structure]
within the shaft of a long bone is a cavity where bone marrow is located.

Red, Yellow

[Bone Structure]
In childhood, the medullary cavity is filled with ____ bone marrow but as we age, fat accumulates within it transforming it to ____ bone marrow.

Periosteum, Endosteum

[Bone Structure]
The ___________ is the outermost covering of bone made primarily of dense irregular tissue and held on by Sharpey’s fibers (collagen), while the ______ is the internal membrane of bone made of connective tissue. This also lines the many canals that pass through bone to supply blood and nerves to the bone.

Nutrient Foramen

[Bone Structure]
- a tunnel that penetrates the diaphysis and provides access for the blood vessels into the shaft of the bone

Nutrient artery, Nutrient vein

[Bone Structure]
The _____2words_____ transports oxygenated, nutrient-rich blood to the bone while the ______2words____ transports deoxygenated, waste-laden blood from the bone.

Both
- generally 1 per bone
- Nutrient foramen in diaphysis for access
- supply osteons in walls and medullary cavity

Metaphyseal artery, Metaphyseal vein

[Bone Structure] [2 answers]
They carry blood to and from the area of themetaphysis and to the epiphysis

Articular Cartilage

[Bone Structure]
- covers joint ends
- covers portions of the epiphysis that articulate with other bones. The
cartilage is avascular, hyaline cartilage. It relies primarily on diffusion from the synovial fluid to obtain oxygen and nutrients and to eliminate wastes.

Osteocyte
Osteoblast
Osteogenic cell
Osteoclast

Osseous Cells [4 answers]
- __________ maintains bone tissue
- __________ forms bone matrix
- _____2 words_____ stem cell
- __________ resorbs bone

Osteocytes

[1 answer] mature bone cells that maintain the protein and mineral content of the surrounding matrix through the turnover of matrix components. ___________ secrete chemicals that dissolve the adjacent matrix, and the release minerals enter the circulation.
- most common
- mature cells in lacunae (spaces)
- maintain matrix by releasing enzymes

Osteoblasts

[1 answer]
- immature bone cells located on the surface of bone; produce new bone matrix in a process called osteogenesis, or ossification. __________ make and release the proteins and other organic components of the matrix.
- they secrete osteoid = collagen matrix
- they secrete hydroxyapatite (calcium slats)

Osteoprogenitor Cells

mesenchymal cells located with the periosteum and endosteum. These stem cells divide to produce daughter cells that differentiate into osteoblasts, and they are
important in the formation of osteocytes

Osteoclasts

bone digesting cells that remove and recycle bone matrix. These are giant cells with 50 or more nuclei. They are not related to osteoprogenitor cells or their descendants. Instead, they are derived from the same stem cells that produce phagocytic white blood cells, called monocytes.

Osteogenesis or Ossification

the process of bone formation

Osteolysis

Acids and proteolytic enzymes secreted by osteoclasts dissolve the matrix and release stored minerals. This process, called __________, or resorption, is important in bone remodeling.

Periosteum

[Bone Structure]
- contains blood vessels/nerves
- site of tendon/ligament attachment

Osteogenic cells

- Mesenchymal stem cells that develop into osteoblasts
- role in bone repair

Compact Bone

- dense and strong bone
- functional unit is osteon
- contains lamellae, central canal, and perforating canals

Lamellae

[Compact Bone part]
- concentric rings of calcified matrix

Central canal

[Compact Bone part]
- these contains blood vessels/nerves

Perforating Canals

[Compact Bone part]
- connect with medullary cavity and periosteum

Cancellous Bone

- commonly known as spongy bone
- located where bones are not heavily stressed in many directions
- osteocytes and lacunae are in network of matrix called trabeculae
- makes bone lighter
- red bone marrow is found between trabeculae

ossification

[process]
- bone replaces hyaline cartilage "template" or forms within connective tissue

Endochondral ossification

[Bone Formation]
– Replaces hyaline cartilage w/ bone and lengthens
– Forms long, short, and irregular bones
– Growth in puberty

Intramembranous ossification

[Bone Formation]
– Mesenchyme (stem) cells transform to osteoblasts in connective tissue
– Most flat bones of skull
- BONE DEVELOPS FROM UNDIFFERENTIATED CELLS IN CONNECTIVE TISSUE

Growth in Puberty

[process]
• Osteoblast activity to outpace chondroblast activity
• Epiphyseal plate narrows

Intramembranous ossification

[process]
(a) Mesenchymal cells group into clusters, become osteoblasts, and form
ossification centers.
(b) Osteoblasts secrete osteoid, traps osteoblasts, which then become osteocytes.
(c) Trabecular matrix forms as osteoid is deposited around capillaries.
(d) Compact bone develops superficial to the trabecular (spongy) bone, and crowded blood vessels condense into red marrow.

Endochondral ossification

[process]
(a) Mesenchymal cells differentiate into chondrocytes.
(b) The cartilage model of the future bony skeleton and the perichondrium form.
(c) Capillaries penetrate cartilage. Perichondrium transforms into periosteum. Periosteal collar develops. Primary ossification center develops.
(d) Cartilage and chondrocytes continue to grow at ends of the bone.
(e) Secondary ossification centers develop.
(f) Cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage.

Longtitudinal Growth

[process]
(a) Chrondrocytes at the epiphyseal side of the cartilage continue to divide and enlarge
(b) Chondrocytes degenerate at the diaphyseal side
(c) Osteoblasts migrate upward from the diaphysis and cartilage is gradually replaced by bone

Longtitudinal Growth

[process]
- Progression from Epiphyseal Plate to Epiphyseal Line
- As a bone matures, the epiphyseal plate becomes an epiphyseal line.
- Occurs in early adulthood when chondrocytes stop dividing

Appositional Growth

[process]
- also known as bone remodeling
– Increases bone diameter of existing bones (Does NOT form NEW bones)
– Osteogenic cells differentiate into osteoblasts that add bone matrix under periosteum
• Adds successive layers of circumferential lamellae
• Trapped osteoblasts become osteocytes
– Deeper lamellae recycled and replaced by osteons
– Osteoclasts remove matrix at inner surface to enlarge medullary cavity

Ca2+

Bones store this ion for
– Necessary for muscle and neuron function
– Hormonal regulation (Intestinal absorption, Osteoblast and –clast activity, Urine composition in kidneys)
– this has directly effect none formation/resorption

Simple

[Bone Fracture]
- known as closed fracture
- skin is intact
- bone breaks cleanly

Compound

[Bone Fracture]
- known as open fracture
- broken ends of bone protrude through the tissue and s

Transverse

[Bone Fracture] break occurs perpendicular to the long axis of

Linear

[Bone Fracture] breaks parallel to the long axis of

Spiral

[Bone Fracture] twisting motion pulls bone
segments apart

Comminuted

[Bone Fracture] several breaks in one bone

Impacted

[Bone Fracture] one fragment is driven into
another (caused by compression)

Greenstick

[Bone Fracture] , one side is broken

Oblique

[Bone Fracture] occurs at angle not 90

Non- displaced

[Bone Fracture Position]
- the bone ends retain their position

Displaced

[Bone Fracture Position]
-the bone end are out of normal alignment