Please enable JavaScript.
Coggle requires JavaScript to display documents.
Skeletal System - Richard Nguyen P.6 - Coggle Diagram
Skeletal System - Richard Nguyen P.6
Skeletal Cartilages
Hyaline Cartilage
Provides support, flexibility, and resilience
Most abundant type; contains collagen fibers only
Articular (joints), costal (ribs), respiratory (larynx), nasal cartilage (nose tip)
Elastic Cartilage
Similar to hyaline cartilage, but contains elastic fibers
External ear and epiglottis
Fibrocartilage
Thick collagen fibers: has great tensile strength
Menisci of knee; vertebral discs
Growth of Cartilage
Appositional Growth
Cartilage-forming cells in perichondrium secrete matrix against external face of existing cartilage
New matrix laid down on surface of cartilage
Interstitial Growth
Chondrocytes within lacunae divide and secrete new matrix, expanding cartilage from within
New matrix made within cartilage
Functions of Bones
Support
For body and soft organs
Protection
Protect brain, spinal cord, and vital organs
Movement
Levers for muscle action
Mineral and Growth Factor Storage
Calcium and phosphorus, and growth factors reservoir
Blood Cell formation
Hematopoiesis occurs in red marrow cavities of certain bones
Triglyceride(fat) storage
Fat, used for an energy source, is stored in bone cavities
Hormone production
Osteocalcin secreted by bones helps to regulate insulin secretion, glucose levels, and metabolism
Classification of Bones
Axial Skeleton
Long axis of body
Skull, vertebral column, rib cage
Appendicular Skeleton
Bones of upper and lower limbs
Girdles attaching limbs to axial skeleton
Based on Shapes
Long Bones
Longer than they are wide
Limb bones
Short Bones
Cube-shaped bones (in wrist and ankle)
Sesamoidbones 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
Gross Anatomy
Compact and spongy bone
Compact bone: dense outer layer on every bone that appears smooth and solid
Spongy bone: made up of a honeycomb of small, needle-like or flat pieces of bone called trabeculae
Open spaces between trabeculae are filled with red or yellow bone marrow
Structure of short, irregular, and flat bones
Consist of thin plates of spongy bone (diploe) covered by compact bone
Compact bone sandwiched between connective tissue membranes
Periosteumcovers outside of compact bone, and endosteumcovers inside portion of compact bone
Bone marrow is scattered throughout spongy bone; no defined marrow cavity
Hyaline cartilage covers area of bone that is part of a movable joint
Structure of typical long bone
Diaphysis: tubular shaft that forms long axis of bone–Consists of compact bone surrounding central medullary cavity that is filled with yellow marrow in adults
Epiphyses: ends of long bones that consist of compact bone externally and spongy bone internally–Articular cartilage covers articular (joint) surfaces
Between diaphysis and epiphysis is epiphysealline–Remnant of childhood epiphysealplatewhere bone growth occurs
Membranes: two types (periosteum and endosteum)
Endosteum•Delicate connective tissue membrane covering internal bone surface•Covers trabeculae of spongy bone•Lines canals that pass through compact bone•Like periosteum, contains osteogenic cells that can differentiate into other bone cells
Periosteum: white, double-layered membrane that covers external surfaces except joints
Cells of Bone Tissues
Osteogenic cells
Also called osteoprogenitorcells–Mitotically active stem cells in periosteum and endosteum–When stimulated, they differentiate into osteoblasts or bone-lining cells–Some remain as osteogenic stem cells
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
Osteocytes
Mature bone cells in lacunae that no longer divide–Maintain bone matrix and act as stress or strain sensors
Bone-liningcells
Flat cells on bone surfaces believed to also help maintain matrix (along with osteocytes)
Osteoclasts
Derived from same hematopoietic stem cells that become macrophages–Giant, multinucleate cells function in bone resorption (breakdown of bone)–When active, cells are located in depressions called resorptionbays–Cells have ruffled borders that serve to increase surface area for enzyme degradation of bone
Microscopic Anatomy of Bone
Compact bone
Also called lamellarbone
Consists of:Osteon(Haversian system)-Canals and canaliculi-Interstitial and circumferential lamellae
Osteon (Haversian system)
An osteon is the structural unit of compact bone–Consists of an elongated cylinder that runs parallel to long axis of bone–An osteon cylinder consists of several rings of bone matrix called lamellae
Canals and canaliculi
Central(Haversian) canal runs through core of osteon
Perforating(Volkmann’s) canals: canals lined with endosteum that occur at right angles to central canal
Lacunae: small cavities that contain osteocytes
Canaliculi: hair like canals that connect lacunae to each other and to central canal
Osteoblasts that secrete bone matrix maintain contact with each other and osteocytes via cell projections with gap junctions
When matrix hardens and cells are trapped the canaliculi form
Spongy bone
Appears poorly organized but is actually organized along lines of stress to help bone resist any stress
Trabeculae, like cables on a suspension bridge, confer strength to bone
Chemical Composition of Bones
Organic components
Includes osteogenic cells, osteoblasts, osteocytes, bone-lining cells, osteoclasts, and osteoid
Resilience of bone is due to sacrificial bonds in or between collagen molecules that stretch and break to dissipate energy and prevent fractures
If no additional trauma, bonds re-form
Inorganic components
Bone is half as strong as steel in resisting compression and as strong as steel in resisting tension
Lasts long after death because of mineral composition -Can reveal information about ancient people
Bone Development
Ossification(osteogenesis) is the process of bone tissue formation
-Formation of bony skeleton begins in month 2 of development–Postnatal bone growth occurs until early adulthood–Bone remodeling and repair are lifelong
Endochondral ossification
-Bone forms by replacing hyaline cartilage–Bones are called cartilage(endochondral) bones–Form most of skeleton
Intramembranous ossification
–Bone develops from fibrous membrane–Bones are called membranebones–Forms frontal, parietal, occipital, temporal, and clavicle bones
Growth in Length of Long Bones
-Near end of adolescence, chondroblasts divide less often-Epiphyseal plate thins, then is replaced by bone-Epiphyseal plate closure occurs when epiphysis and diaphysis fuse-Bone lengthening ceases
–Females: occurs around 18 years of age–Males: occurs around 21 years of age
Growth in Width (Thickness)
-Growing bones widen as they lengthen through appositional growth
-Bones thicken in response to increased stress from muscle activity or added weight
-Usually more building up than breaking down which leads to thicker, stronger bone that is not too heavy
Bone Remodeling
Bone remodeling consists of both bone deposit and bone resorption
Resorption is function of osteoclasts
Osteoclasts also phagocytize demineralized matrix and dead osteocytes
Bone Deposit: New bone matrix is deposited by osteoblasts
Fracture Classification
–Position of bone ends after fracture▪Nondisplaced: ends retain normal position▪Displaced: ends are out of normal alignment
–Completeness of break▪Complete:broken all the way through▪Incomplete:not broken all the way through
–Whether skin is penetrated▪Open(compound):skin is penetrated▪Closed(simple):skin is not penetrated
Bone Fracture Repair
Hematoma formation–Torn blood vessels hemorrhage, forming mass of clotted blood called a hematoma–Site is swollen, painful, and inflamed
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
Bony callus formation–Within one week, new trabeculae appear in fibrocartilaginous callus–Callus is converted to bony(hard) callus of spongy bone–Bony callus formation continues for about 2 months until firm union forms
Bone remodeling–Begins during bony callus formation and continues for several months–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
Bone Disorders
Osteomalacia and rickets
Osteomalacia–Bones are poorly mineralized–Osteoid is produced, but calcium salts not adequately deposited–Results in soft, weak bones–Pain upon bearing 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
Osteoporosis
Osteoporosisis a group of diseases in which bone resorption exceeds deposit
Matrix remains normal, but bone mass declines
Risk factors for osteoporosis–Most often aged, postmenopausal women
Additional risk factors for osteoporosis:–Insufficient exercise to stress bones
Treatingosteoporosis–Traditional treatments
Preventingosteoporosis–Plenty of calcium in diet in early adulthood–Reduce consumption of carbonated beverages and alcohol
Paget’s disease
Excessive and haphazard bone deposit and resorption cause bone to grow fast and develop poorly
Usually occurs in spine, pelvis, femur, and skull•Rarely occurs before age 40•Cause unknown: possibly viral•Treatment includes calcitonin and bisphosphonates
Classification of Joints
Structural: three types based on what material binds the joints and whether a cavity is present
Fibrous
–Sutures
Rigid, interlocking joints of skull
In middle age, sutures ossify and fuse
Allow for growth during youth
–Syndesmoses
Bones connected by ligaments, bands of fibrous tissue-Fiber length varies, so movement varies
–Gomphoses
Peg-in-socket joints•Only examples are the teeth in alveolar sockets•Fibrous connection is the periodontalligament
Cartilaginous
Bones united by cartilage•Like fibrous joints, have no joint cavity•Not highly movable
–Symphyses
Fibrocartilage unites bone in symphysisjoint–Hyaline cartilage also present as articular cartilage on bony surfaces•Symphyses are strong, amphiarthrotic (slightly movable) joints
–Synchondroses
Bar or plate of hyaline cartilage unites bones•Almost all are synarthrotic (immovable)
Synovial
Bones separated by fluid-filled joint cavity•All are diarthrotic (freely movable)•Include almost all limb joints
Characteristics of synovial joints –Have six generalfeatures–Have bursaeandtendonsheathsassociated with them –Stabilityis influenced by three factors–Allow several types of movements–Classified into six differenttypes
Articular cartilage: consists of hyaline cartilage covering ends of bones
Joint (synovial) cavity: small, fluid-filled potential space that is unique to synovial joints
Articular (joint) capsule: two layers thick▪External fibrouslayer: dense irregular connective tissue▪Inner synovialmembrane: loose connective tissue that makes synovial fluid
Synovial fluid: viscous, slippery filtrate of plasma and hyaluronic acid ▪Lubricates and nourishes articular cartilage
Capsular: thickened part of fibrous layer▪Extracapsular: outside the capsule▪Intracapsular: deep to capsule; covered by synovial membrane
Nerves and blood vessels
Functional classifications: three types based on movement joint allows
Synarthroses: immovable joints
Amphiarthroses: slightly movable joints
Diarthroses: freely movable joints
Types of Synovial Joints
Plane
Hinge
Pivot
Condylar
Saddle
Ball-and-Saddle
Movements allowed by Synovial Joints
Range of motion allowed by synovial joints
Nonaxial: slipping movements only
–Uniaxial: movement in one plane
–Biaxial: movement in two planes
–Multiaxial: movement in or around all three planes
Three general types of movements
Gliding
One flat bone surface glides or slips over another similar surface
Angular Movements
Increase or decrease angle between two bones–Movement along sagittal plane
Abduction: movement along frontal plane, away from the midline
Adduction: movement along frontal plane, toward the midline
Circumduction
Rotation
turning of bone around its own long axis, toward midline or away from it
–Medial: rotation toward midline
–Lateral: rotation away from midline
Special Movement
Supinationand pronation: rotation of radius and ulna
Dorsiflexionand plantarflexionof foot
Inversionand eversionof foot
Elevationand depressionof mandible
Opposition: movement of thumb
Difference Between Male and Female Skeleton
The female pelvis is designed to offer optimal space for the birth canal, which is reflected in its morphology and the relationship of its parts to each other
Bones in the Body
SKull
Frontal Bone (Forehead)
Nasal Bone (Nasals)
Ethmoid Bone (Supporting Bone of Nasal Cavity)
Lacrimal Bone
Vomer Bone (Lower portion of nasal septum)
Zygomatic Bone (Cheek Bone)
Maxilla (Upper Jaw)
Mandible (Lower Jaw)
Temporal Bone (Temple)
Sphenmoid Bone (Wasp Bone)
Parietal Bone (Side of skull)
Occipital Bone (Back of Bone)
Thoracic Cage
Clavicle (Collarbone)
Scapula (Shoulder Blade)
RIbs
False Ribs
Floating Ribs
True Ribs
Sternum
Manubrim
Body
Xiphoid process
Vertebral
Vertebral (Spine/Backbone)
Thoracic(Chest VErtebrae)
Lumbar Lower Back Vertebrae
Sacrum
Cervical
Atlas A
Axis
Upper Limbs
Humerus
Ulna
Radius
Carpal
Metacarap
Phalanges
Clavicle
Scapula
Lower Limb
Femur
FibullaR
Tibia
Patella
Tarsal
Metatarsals
Phalanges