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Human AnatomyHuman Anatomy
Skeletal SystemSkeletal System
Functions Functions
• Support:Support: body structure and shape body structure and shape
• ProtectionProtection for vital organs (brain, heart, etc.) for vital organs (brain, heart, etc.)
• MovementMovement for attached skeletal muscles for attached skeletal muscles – Tendons:Tendons: attach muscle to bone attach muscle to bone – Ligaments:Ligaments: attach bone to bone attach bone to bone
• Mineral storageMineral storage:: calcium and phosphorus calcium and phosphorus
• Blood cell formationBlood cell formation - hematopoiesis - hematopoiesis
Types of BoneTypes of Bone
Compact BoneCompact Bone• Very dense, stress bearing Very dense, stress bearing • Haversian systemsHaversian systems –basic unit –basic unit
of compact boneof compact bone• LamellaeLamellae: concentric cylinder : concentric cylinder
shaped calcified structure shaped calcified structure • LacunaeLacunae: small spaces containing : small spaces containing
tissue fluid tissue fluid • OsteocytesOsteocytes: facilitate exchange of : facilitate exchange of
calcium between blood and bone calcium between blood and bone • CanaliculiCanaliculi: canals connecting the lacunae together : canals connecting the lacunae together
and to the haversian canal which carries nutrients and to the haversian canal which carries nutrients and wastes to and from the osteocytes and wastes to and from the osteocytes
Cancellous Bone Cancellous Bone
• Light, spongy Light, spongy
• Found at ends of long bones, ribs, Found at ends of long bones, ribs, sternum, hips, vertebrae, cranium sternum, hips, vertebrae, cranium
• No haversian systems No haversian systems
• Web-like arrangement Web-like arrangement
• Highly vascularHighly vascular
Classification of BonesClassification of Bones
Long bones Long bones • Found in the extremitiesFound in the extremities• Act as levers Act as levers • Includes:Includes:
– EpiphysisEpiphysis• End of long bonesEnd of long bones• Covered with hyaline cartilage for articulation Covered with hyaline cartilage for articulation • Filled with cancellous bone Filled with cancellous bone
– DiaphysisDiaphysis– Shaft Shaft – Covered with periosteumCovered with periosteum– Medullary canal Medullary canal – Compact bone Compact bone
• Examples: femur, tibia, fibula, humerus, Examples: femur, tibia, fibula, humerus, radius, clavicle, metacarpals, phalanges radius, clavicle, metacarpals, phalanges
Short Bones Short Bones
• Cube shaped Cube shaped
• Allows flexible movement Allows flexible movement
• Cancellous bone covered by compact Cancellous bone covered by compact bone bone
• Examples: Examples: – Carpals Carpals – TarsalsTarsals
Flat Bones Flat Bones
• Protect vital organs and provide broad Protect vital organs and provide broad surface area for muscle attachment surface area for muscle attachment
• Examples: Examples: – Cranial bonesCranial bones– ScapulaScapula– Sternum Sternum – RibsRibs
Irregular Bones Irregular Bones
• Peculiarly shaped to provide support and Peculiarly shaped to provide support and protection, yet allow flexibility protection, yet allow flexibility
• Examples:Examples:– VertebraeVertebrae– Ear Ear – HyoidHyoid– Mandible Mandible
Sesamoid Bones Sesamoid Bones
• Extra bones found in certain tendons Extra bones found in certain tendons
• Example:Example:– PatellaPatella
Composition Composition
• Collagen: chief organic constituent (protein) Collagen: chief organic constituent (protein) • Inorganic calcium salts (Vitamin D essential for absorption Inorganic calcium salts (Vitamin D essential for absorption
of minerals i.e. calcium) of minerals i.e. calcium)
• Deposition favored by Deposition favored by – a. Estrogen, testosterone a. Estrogen, testosterone – b. Alkaline phosphatase b. Alkaline phosphatase – c. Thyrocalcitonin c. Thyrocalcitonin – d. Mechanical stress i.e. traction d. Mechanical stress i.e. traction
• Withdrawal favored by Withdrawal favored by – a. Alkaline phosphatase a. Alkaline phosphatase – b. Parathormone b. Parathormone – c. Inactivity c. Inactivity
Composition Composition
Cells Cells • Osteoblasts: bone building, bone repairing cells in the Osteoblasts: bone building, bone repairing cells in the
periosteum periosteum • Osteocytes: mature bone cells within the bone matrix Osteocytes: mature bone cells within the bone matrix • Osteoclast: causes reabsorption of bone Osteoclast: causes reabsorption of bone
Periosteum Periosteum • 1. Dense, fibrous membrane covering bone 1. Dense, fibrous membrane covering bone • 2. Contains blood vessels 2. Contains blood vessels • 3. Essential for bone cell survival and bone formation 3. Essential for bone cell survival and bone formation •
Osteoblast
Osteocyte
OsteoclastEats bone
Builds new bone
Mature bone cell
Cells that Aid in Bone FormationCells that Aid in Bone Formation
Bone Formation Bone Formation • Initially collagen fibers secreted by fibroblasts Initially collagen fibers secreted by fibroblasts
• Cartilage deposited between fibers Cartilage deposited between fibers
• Skeleton fully formed by 2nd month of fetal development (all Skeleton fully formed by 2nd month of fetal development (all cartilage) cartilage)
• After 8th week of fetal development ossification (mineral matter After 8th week of fetal development ossification (mineral matter deposited and replaces cartilage) begins deposited and replaces cartilage) begins
• Childhood and adolescence: Childhood and adolescence:
– ossification exceeds bone lossossification exceeds bone loss
• Early adulthood thru middle age: Early adulthood thru middle age:
– ossification equals bone lossossification equals bone loss
• After age 35: After age 35: – bone loss exceed ossificationbone loss exceed ossification
275 bones275 bones12 weeks 12 weeks
(6-9 inches long)(6-9 inches long)
Fetal Skeleton Fetal Skeleton
Anatomy of Long BoneAnatomy of Long Bone• Diaphysis Diaphysis
– ShaftShaft– Composed of compact boneComposed of compact bone
• Epiphysis Epiphysis – Ends of bone composed mostly Ends of bone composed mostly
of spongy boneof spongy bone
• Periosteum Periosteum – outside covering of diaphysisoutside covering of diaphysis
• EndosteumEndosteum– Lines medullary cavityLines medullary cavity
• ArteriesArteries• Articular cartilageArticular cartilage• Medullary cavityMedullary cavity
– Cavity inside the shaft Cavity inside the shaft – Contains yellow marrow (mostly fat) in adultsContains yellow marrow (mostly fat) in adults
Bone MarrowBone Marrow
• Red bone marrowRed bone marrow– Found in vertebrae, ribs, sternum, cranium, Found in vertebrae, ribs, sternum, cranium,
ends of humerus and femurends of humerus and femur– Produces:Produces:
• ErythrocytesErythrocytes – red blood cells – red blood cells• Plateletes - thrombocytesPlateletes - thrombocytes – clotting cells – clotting cells• Some Some leukocytesleukocytes – white blood cells – white blood cells
• Yellow bone marrowYellow bone marrow– Found in medullary cavity of long bones Found in medullary cavity of long bones – Fat storage Fat storage
Bone MarrowBone Marrow
Yellow marrowYellow marrow • Medullary cavity of long bones Medullary cavity of long bones • Fat storage Fat storage
Red marrowRed marrow• Hematopoietic tissue Hematopoietic tissue • In all cancellous bone in children In all cancellous bone in children • In adults: cancellous bone of vertebrae, hips, sternum, In adults: cancellous bone of vertebrae, hips, sternum,
ribs, cranial bones, proximal ends of femur and humerus ribs, cranial bones, proximal ends of femur and humerus • Forms RBCs, platelets, some WBCs, and destroys old Forms RBCs, platelets, some WBCs, and destroys old
RBCs and some foreign materials RBCs and some foreign materials
Divisions of the Divisions of the Skeletal SystemSkeletal System
Axial SkeletonAxial Skeleton
Forms the longitudinal axis of the bodyForms the longitudinal axis of the body
Divided into three parts: then subdividedDivided into three parts: then subdivided• SkullSkull• CraniumCranium• Ear bonesEar bones• Face Face • Vertebral ColumnVertebral Column• ThoraxThorax• Ribs Ribs • SternumSternum• Hyoid boneHyoid bone
Ribs: Fixed, False and FloatingRibs: Fixed, False and Floating
Appendicular SkeletonAppendicular Skeleton
• Composed of 126 bonesComposed of 126 bones
• Includes bones of the:Includes bones of the:– Limbs (appendages) Limbs (appendages) – Pectoral (shoulder) girdlePectoral (shoulder) girdle– Pelvic (hip) girdlePelvic (hip) girdle
Man VS WomanMan VS Woman
• Difference:Difference:– Men bigger and pelvic inlet shaped like a Men bigger and pelvic inlet shaped like a
funnelfunnel– Woman smaller and pelvic inlet shaped like a Woman smaller and pelvic inlet shaped like a
basin to cradle the baby and the outlet is basin to cradle the baby and the outlet is much widermuch wider
JointsJoints
ClassificationClassification
• SynarthroticSynarthrotic: immovable - cranium: immovable - cranium• AmphiarthroticAmphiarthrotic: limited movement i.e. : limited movement i.e.
pubic symphysis, vertebral joints, pubic symphysis, vertebral joints, sacroiliac joint sacroiliac joint
• DiarthroticDiarthrotic: freely movable : freely movable – Gliding: bones of the wrist Gliding: bones of the wrist – Pivot: between radius and ulna Pivot: between radius and ulna – Ball and socket: hip Ball and socket: hip – Hinge: elbow Hinge: elbow
Immovable Joints Immovable Joints SynarthrosisSynarthrosis
Slightly Movable Joint Slightly Movable Joint AmpharthrosisAmpharthrosis
Freely Movable DiarthrosisFreely Movable Diarthrosis
Abduction
Extension
RotationFlexion
Adduction
Synovial Joint Movement
Diseases / DisordersDiseases / Disorders
• ArthritisArthritis• BunionsBunions• BursitisBursitis• DislocationDislocation
• SimpleSimple• CompoundCompound• Greenstick Greenstick • ComminuntedComminunted