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Alexis Zatarain Per. 3 Skeletal System - Coggle Diagram
Alexis Zatarain Per. 3 Skeletal System
Microscopic Anatomy
Osteogenic cells
Mitotically active stem cells in periosteum and endosteum When stimulated, they differentiate into osteoblasts or bone-lining cells
Osteoblasts
Bone-forming cells that secrete unmineralized bone matrix called osteoid, Osteoblasts are actively mitotic
Osteocytes
Mature bone cells in lacunae that no longer divide, Maintain bone matrix and act as stress or strain sensors, Communicate information to osteoblasts and osteoclasts
Bone-lining cells
Flat cells on bone surfaces believed to also help maintain matrix
Osteoclasts
Giant, multinucleate cells function in bone resorption, When active, cells are located in depressions called resorption bays, helps seal off area from surrounding matrix
Compact bone
Osteon (Haversian system)
structural unit of compact bone, elongated cylinder that runs parallel to long axis of bone, osteon cylinder consists of several rings of bone matrix called
lamellae
Lamellae
contain collagen fibers that run in different directions in adjacent
rings, Withstands stress and resist twisting
Canals and canaliculi
Central (Haversian) canal runs through core of osteon, Contains blood vessels and nerve fibers
Perforating (Volkmann’s) canals: canals lined with endosteum that occur at right angles to central canal, Connect blood vessels and nerves of periosteum, medullary cavity, and central
canal
Lacunae: small cavities that contain osteocytes
Canaliculi: hairlike canals that connect lacunae to each other and to central canal
interstitial and circumferential lamellae
Spongy Bone
organized along lines of stress to help
bone resist any stress
Capillaries in endosteum supply nutrients
Bone Remodeling
Resorption
function of osteoclasts, Dig depressions or grooves as they break down matrix,Secrete lysosomal enzymes and protons that digest matrix, Acidity converts calcium salts to soluble forms
Deposit
New bone matrix is deposited by osteoblasts
Occurs at surfaces of both periosteum and endosteum, packets of adjacent osteoblasts and osteoclasts coordinate
remodeling process
Bone Fracture Repair
Hematoma formation
Torn blood vessels hemorrhage, forming mass of clotted blood called
a hematoma
Fibrocartilaginous callus formation
Capillaries grow into hematoma, Phagocytic cells clear debris, Fibroblasts secrete collagen fibers to span break and connect broken
ends, Fibroblasts, cartilage, and osteogenic cells begin reconstruction of
bone
Create cartilage matrix of repair tissue, Osteoblasts form spongy bone within matrix
Bony callus formation
new trabeculae appear in fibrocartilaginous callus, Callus is converted to bony callus of spongy bone, continues for about 2 months until firm union forms
Bone remodeling
Excess material on diaphysis exterior and within medullary cavity is removed, Compact bone is laid down to reconstruct shaft walls, Final structure resembles original structure
Disorders/diseases
Osteomalacia & Rickets
Bones are poorly mineralized, Results in soft, weak bones
Children: Results in bowed legs and other bone deformities because bones ends
are enlarged and abnormally long, vitamin D deficiency or insufficient dietary calcium
Osteoporosis
bone resorption exceeds deposit, Matrix remains normal, but bone mass declines
RIsks:postmenopausal women, Insufficient exercise to stress bones, Smoking, Diet poor in calcium and protein
Treating osteoporosis: Calcium, Vitamin D supplements, Weight-bearing exercise, Hormone replacement therapy, Bisphosphonates, Denosumab
Paget's Disease
Very high ratio of spongy to compact bone and reduced mineralization, occurs in spine, pelvis, femur, and skull, Treatment includes calcitonin and bisphosphonates
Types of Bones
Long bones
Longer than they are wide, Limb bones (arm)
Short Bones
Cube-shaped bones (in wrist and ankle), Sesamoid bones form within tendons (example: patella), Vary in size and number in different individuals
Flat bones
Thin, flat, slightly curved, Sternum, scapulae, ribs, most skull bones
Irregular bones
Complicated shapes, Vertebrae and hip bones
Joints
Structural: three types based on what material binds the joints and whether a cavity is present
Fibrous Joints: bones joined by dense fibrous connective tissue
Sutures: rigid, interlocking joints of skull, allow for growth duringyouth & in middlle age, they ossify and fuse
Syndesmoses: bones connected by ligmants, bands of fibrous tissue (short fibers offer little to no movements) (longer fibers offer a larger amount of movement)
Gomphoses: peg-in-socket joints & fibrous connection is the periodontal ligament
Cartilaginous Joints: bones unitede by cartilage
Synchondroses: bar/plate of hyaline cartilage unites bones (immoveable
Symphyses: fibrocartilage unites bone in symphysis joint (slightly moveable)
Synovial Joints: bones seperated by fluid-filled joint cavity (Articular cartilage, Joint cavity, Articular capsule, Synovial fluid, reinforcing ligaments and nerves and blood vessels)
Functional: three types based on movement joint allows
Synthroses:immoveable joints
Amphiarthroses:slightly moveable joints
Diarthroses: freely moveable joints
Movements Allowed by Synovial Joints
Lateral Rotation: Rotating away the median plane
Rotation: Medial Rotation: rotating toward the median plane
Circumduction: moving a limb or finger so that it describes a cone in space
Adduction: moving a limb toward from the body midline in the frontal plane
Abduction: moving a limg away forom the midline in the frontal plane
Extension: incresing the angke between two bones, usually in the sagittal
Angular: Flexion: decreasing the angle between two bones, usually in the sagittal plane
Gliding: sliding the flat surfaces of two bones accross eachother
Nonaxial: slipping movements only, Uniaxial: movemnt in one pkane, Biaxial: movement in two planes, & Multiaxial:movemnt in or around all three planes
Origin: attachemnt to immovable bone and Insertion: attachment to moveable bone
Supination & Pronation: rotation of radius and ulna
Dorsiflexion bending foot toward shin & Plantar Flexion of foot: pointing toes
Inversion: sole of foot faces medially and Eversion: sole of foot faces laterally
Protraction and retraction: movement in lateral plane
Elevation: lifting body part superiorly and Depression: lowering body part
Opposition: movement of thumb
Male & Female Skeleton Differences
Male: larger, heavier, thicker/denser bones, pelvis is narrow/deep, femur is thicker, skull is larger and heavier
Female: smaller, lighter, thinner/lighter bone, pelvis shape is wider/shallow, femur is thinner, skull is smaller/lighter
Anatomy of Long Bone
Gross Anatomy
Compact Bone: dense outer layer on every bone that appears smooh and solid
Spongy Bone: made up of trabeculae
Diaphysis:tubular shaft that forms long axis of bone
Epiphyses: ends of long bone that consist of compact bone externally and spngy bone internally
Epiphyseal Line: between diaphysis and epiphysis
Membranes
Periosteum: white, double layered membrane covering external surface except joints
Fibrous Layer: outer layer consisting of dense irregular connective tissue
Osteogenic Layer: inner layer abutting bone and contains primitive osteogenic stem cells that give rise to most all bone cells
Endosteum: delicate conetive tissue membrane covering internal bone surface, coverts ttrabeculae of spongy, and contains osteogenic cells that can differentiate into toher bone cells
Red Marrow: found within trabecular cavities of spongy bone and diploe og flat bones (sternum) Yellow marrow can convert to red
Newborns: Medullary cavities and all spongy bone contatinn red marrow Adults: red marrow is located in heads of femur and humerus
Bone Markings: Sites of muscle, ligament, and tendon attachment on external surfaces
Projection: outward bulge of bone
Depression: bowl like cut out that can serve as passageways for vessels and nerves
Opening: Hole or canal in bone that serves as passageway for blood vessels and nerves
Bones of the Body
Frontal bone (Forehead bone):Forms the front of the skull and upper eye sockets
Mandible (Lower jaw):only movable skull bone; holds the lower teeth
Zygomatic bone(cheek bone): Gives shape to the cheeks and forms part of the eye socket.
Occipital bone(Back of skull):Forms the base and back of the skull
Clavicle(Collarbone):Connects the sternum to the shoulder
Scapula(Shoulder blade):Flat, triangular bone at the back of the shoulder.
Sternum(Breastbone):Long flat bone in the center of the chest;
Humerus(Upper arm bone):Connects the shoulder to the elbow.
Radius(Outer forearm bone):allows wrist rotation.
Ulna(Inner forearm bone):Forms the elbow joint and supports the forearm.
Carpals(wristbones): eight small bones that make up the wrist.
Vertebrae(backbones):small bones forming the spinal column.
Ribs(rib bones):cage that protects the heart and lungs.
Pelvis(hip bone):Supports the spine and connects to the legs.
Femur(thigh bone):longest and strongest bone in the body.
Patella(kneecap):Protects the knee joint
Tibia(Shin bone):weight-bearing bone of the lower leg
Fibula(calf bone):bone on the outside of the lower leg.
Tarsals(ankle bones):seven bones forming the ankle and heel.
Phalanges(finger&toe bones):Small bones that make up the digits