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Esther Ramirez Period #5 Skeletal - Coggle Diagram
Esther Ramirez
Period #5
Skeletal
Microscopic Anatomy of Bone Tissue
5 Major Types of Bone Tissue
1) Osteogenic cells: AKA osteoprogenitor cells. Mitotically active stem cells in periosteum and endosteum. When stimulated, they differentiate into osteoblasts or bone-lining cells. Some remain as ostrogenic stem cells.
2) Osteoblasts: Bone-forming cells that secrete unmineralized bone matrix called osteoid; osteoid is made up of collagen and calcium-binding proteins; collagen makes up 90% of bone protein. Osteoblasts are actively mitotic.
3) Osteocytes: Mature bone cells in lacunae that no longer divide. Maintain bone matrix and act as sstressor strain sensors; respond to mechanical stimuli such as increased force on bone or weightlessness; communicate information to osteoblasts and osteoclases (cells that destroy bone) so that bone remodeling can occur.
4) Bones-lining cells: Flat cells on bone surfaces believed to also help maintain matrix (along with ostrocytes)
5) Osteoclases: Derived from same hematopietic stem cells that become macrophages. Giant, multinucleated cells function in bone resorption (breakdown of bone). When active, cells are located in depressions called resorption bays. Cells have ruffled borders that serve to increase surface area for enzyme degradation of bone; also helps seal off area from surrounding martix
The 4 Classification of the Bones
Long bones: They are longer than they are wide; limb bones.
Short bones: Cube-shaped bones (in wrist and ankle) and sesamoid bones from within tendons (ex. patella).
Flat bones: They are thin, flat, and slightly curved. Located in the sternum, scapulae, ribs, and most skull bones.
Irregular bones: They are complicated shapes; ex. vertebrae and hip bones.
Facts: 206 named bones in skeleton. It is divided into 2 groups based on location
Axial region: long axis of body; located in the skull, vertebral column, and rib cage
Appendicular skeleton: bones of upper and lower limbs; girdles attaching limbs to axial region
Bone Names
Skull
Frontal bone, coronal suture, sagittal suture, lambdoid suture, squamous suture, parietal bone, temporal bone, sphenoid bone, frontal bone, mandible, maxilla, nasal, zygomatic, vomer bone, palatine bone, occipital bone,
Lower Extremity
Pelvis, femur,, patella, tibia, fibula, tarsal, calcaneous, metatarsals, and phalanges.
Upper Extremity
Clavicle, scapula, humerus, ulna, radius, carpals, metacarpals, and phalanges.
Pelvis
Ilium, ischium, lumbar vertebrae, base of sacrum, coxal, sacrum, pubic synthesis, pubis, coccyx,
Vertical Column
Cervical vertebra, thoracic vertebrae, lumbar vertebrae, sacrum, and coccyx.
Long Bone
Articular cartilage, proximal diaphysis, diaphysis, distal diaphysis, compact bone, yellow bone marrow, red bone marrow, spongy bone, epiphyseal plate, periosteum, endosteum, distal epiphysis, and medullary cavity.
Rib Cage
True ribs, false ribs, sternum, xphoid process, costal cartilage, and floating ribs
Bone Remodeling
Bone remodeling consists of both bone deposit and bone resorption. It occurs at the surfaces of both periosteum and endosteum. Remodeling units are packets of adjacent osteoblasts and osteoclasts coordinate remodeling process.
Resorption is a function of the osteoclasts. They dig depressions or gooves as they break down the matix, secrete lysosomal enzymes and protons (H^+) that digest matrix, and the acidity converts calcium salts to soluble forms.
Osteoclasts also phagocytize demineralize matriz and dead osteocytes. Bone deposit is the process of the new-bone matrix when it is deposited by osteoblasts.
Bone Fracture Repair
Ossification (osteogenesis) is the process of bone tissue formation.
1) Formation of a bony skeleton begins in month 2 of development
2) Postnatal bone growth occurs until early adulthood
3) Bone remodeling and repair are lifelong
The formation of the Bony Skeleton takes up to 8 weeks. The fibrous membranes and hyaline cartilage of fetal skeleton are replaced with bone tissue.
Endochondral ossification: Bone forms by replacing hyaline cartilage. It also forms most of the skeleton; forms essentially all bones interior to base of skull, except the clavicles.
Intramembranous ossification: Bone develops from fibrous membrane; this is called the membrane bones. It forms the frontal, parietal, occipital, temporal, and clavicle bones.
3 Fracture Classifications:
1) Position of bone ends after the fracture; non-displaced: ends retain normal position; displaced: ends are out of normal alignment
2) Completeness of break; complete: broken all the way through; incomplete: not broken all the way through
3) Whether skin is penetrated; open (compound): skin is penetrated; closed (simple): skin is not penetrated
Can also be described by location of fracture, external appearance, and nature of break.
Joints
Joints also called articulations are sites where 2+ bones meet.
-Functions: give skeleton mobility and hold skeleton together
2 classifications:
1) Structural: 3 types based on what material binds the joints and whether a cavity is present fibrous, cartilaginous, and synovial joints.
2) Functional Classifications: 3 types based on movement joint allows
Synarthroses: immovable joints
Amphiarthorses: slightly movable joints
Diarthroses: freely moveable joints
Structural classifications are more clear cut
Movement Allowed by Synovial Joints
Bones separated by fluid-filled joint cavity
All are diarthoratic (freely movable)
Include almost all limbs joints
Characteristics of Synovial Joints
Have 6 general features
Have bursae and tendon sheaths associate with them
Stability is influenced by 3 factors
Allow several types of movements
Classified into six different types
General Structures
1) Articular Cartilage: consists of hyaline cartilage covering ends of bones; prevents crushing of bone ends
2) Joint (synovial) cavity: small, fluid filled potential space that is unique to synovial joints
3) Articular (joint) capsule: 2 layers thick
External fiberous layer: dense irregular connective tissue
inner synovial membrane: loose connective tissue that makes synovial fluid
4) Synovial Fluid: viscous, slippery filtrate of plasma and hyaluronic acid
lubricates and nourishes articular cartilage
Contains phagocytic cells to remove microbes and debris
5) Different types of reinforcing ligaments
Capsilar: thickend part of fibrous layer
Extracapuslar: outside the capsule
Intracapsular: deep to capsule; covered by synovial membranes
6) Nerves and blood vessels:
nerves detect pain; monitor joint position and stretch
capillary beds supply filtrate for synovial fluid
Plane, Hinge, Pivot, condylar, saddle, ball-and-socket
Differences Between Male and Female Skeleton
In the pelvic bone, there are obvious differences between the female pelvis and the male pelvis. The female pelvis has a larger and more expanded pelvic grim than the male. Also, the male hip bone is stretched out from the direction of superior and inferior while the female hip bone has a greater lateral width. Lastly, the sub-pubic angles is wider for female than male because females give birth and males can’t.
Disorders and Diseases
Imbalances between bone deposit and bone resorption underlie nearly every diseases that affects the human skeleton.
3 major bone diseases/disorders:
1) Osteomalacia & rickets: Osteomalacia - bones are poorly mineralized, osteoid is produced but calcium salts are not adequately deposited, results in soft and weak bones, and pain comes upon weight.
Rickets (osteomalacia of children) - results in bowed legs and other bone deformities because bones ends are enlarged and abnormally long. *Cause: vitamin D deficiency or insufficient dietary calcium.
2) Osteoporosis: Osteoporosis is a group of diseases in which bone resorption exceeds deposit. Matrix remains normal, but bone mass declines; spongy bone of spine and neck of femur most susceptible, vertebral and hip fractures are common.
3) Paget's Disease: Excessive and haphazard bone deposit resorption cause bone to grow fast and develop poorly. Has a very high ratio of spongy to compact bone and reduced mineralized. Usually occurs in spine, pelvis, femur, and skull. Rarely occurs before age 40. Cause unknown: possibly viral. Treatment includes calciton and bisphosphonates.
Sinuses
The sinuses are located in the frontal bone and maxillary bones. They include the frontal sinuses, ethonoidal cells, air cells (sinus), maxillary sinus, and sphenodial sinuses. They all collaborate in keeping moist areas in the cavities such as the nasal bone and the occipital bone.
Different Sinuses: Frontal sinus, ethmoidal air cells (sinus), maxillary sinus,
and sphenoidal sinus.