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Human anatomy and physiology

Description

                                  Skeletal System
                                                                                                                Skeletal Anatomy
bones, cartilage and ligaments are tightly joined to
 form a strong, flexible framework                                              each individual bone is a separate organ of the
                                                                                  skeletal system
bone is active tissue:
  !5-7% bone mass/week                                                              ~270 bones (organs) of the Skeletal System

Functions of Skeletal System:                                                                with age the number decreases as bones fuse

        1. Support                                                                               by adulthood the number is 206                                   (typical)
                          strong and relatively light; 20% body weight

        2. Movement                                                                          even this number varies due to varying numbers
                          framework on which muscles act                                       of minor bones:
                          act as levers and pivots
                                                                                                     sesamoid bones – small rounded bones that form within
        3. Protection                                                                                    tendons in response to stress
             brain, lungs, heart, reproductive system
                                                                                                                   eg. kneecap (patella), in knuckles
        4. Mineral storage (electrolyte balance
             99% of body’s calcium is in bone tissue                                                 wormian bones –bones that form within the sutures of
             (1200-1400g vs <1.5g in blood, rest in cells)                                              skull
             also stores phosphate
                                                                                each skeletal organ is composed of many kinds of
        5. Hemopoiesis                                                            tissues:
             blood cell formation
                                                                                             bone (=osseous tissue)
        6. Detoxification                                                                    cartilage
             bone tissue removes heavy metals and other foreign materials                    fibrous connective tissues
                  from blood                                                                 blood (in blood vessels)
             can later release these materials more slowly for excretion                     nervous tissue
             but this can also have bad consequences
                                                                                General Shapes of Bones

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bones can be categorized according to their general                             the general structure of a typical longbone:
  shape:

    1. long:                  cylindrical, longer than wide
                                                                                        articular cartilage
             rigid levers for muscle actions eg crowbars                                                                                                    epiphysis
                                                                                        periosteum
             eg. arms, legs, fingers, toes
                                                                                        medullary cavity                                                    diaphysis
    2. short: length nearly equal width
                                                                                        endosteum

             limited motion, gliding if any
                                                                                                                                                            epiphysis
             eg. carpals, tarsals, patella

    3. flat: thin sheets of bone tissue
                                                                                        epiphyses
             enclose and protect organs
                                                                                             large surface area for muscle attachment and pivot

             broad surfaces for muscle attachments                                           spongy bone with trabeculae;

             eg. sternum, ribs, most skull bones, scapula, os coxa                               contains red marrow (=hemopoietic tissues)

    4. irregular: elaborate shapes different from above                                              ! produces blood cells in delicate mesh of reticular
                                                                                                       tissues
             eg. vertebrae, sphenoid, ethmoid
                                                                                                     in adults red marrow is limited to vertebrae, sternum,
                                                                                                        ribs, pectoral and pelvic girdles, proximal heads of
Bone Structure                                                                                          humerus and femur

bones have outer shell of compact bone                                                               with age, red marrow is replaced by yellow marrow


usually encloses more loosely organized bone tissue                                     articular cartilage
  = spongy (=cancellous) bone                                                                on surface of epiphyses


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             resilient cushion of hyaline cartilage                                                     highly organized arrangement of matrix and
                                                                                                            cells
        diaphysis
                                                                                                                                                                   lacunae w osteocyte
             thick compact bone but light; hollow ! medullary cavity                                                                                                  & canaliculi

        medullary cavity                                                                                                                                           lamellae

                                                                                                                                                                   haversian canal
             yellow marrow – fat (adipose) storage

                  “fat at the center of a ham bone”                                                     perforating canals (Volkmann canals)
                                                                                                          interconnect the haversian canals
                 in event of severe anemia, yellow marrow can
                    transform back into red marrow to make blood cells
                                                                                               periosteum provides life support system for
        periosteum                                                                                     bone cells
             white fibrous connective tissue continuous with tendons
             penetrates bone – welds blood vessels to bone                                     blood vessels penetrate bone and connect with
                                                                                                       those in haversian canals
        endosteum
             fibrous CT that lines medullary cavity                                        B. cartilage
Microscopic Structure (Histology)                                                              resembles bone:
                                                                                                   large amount of matrix
A. bone:
                                                                                                   lots of collagen fibers
             connective tissue; contains cells and matrix
                                                                                               differs:
                                                                                                    firm flexible gel is not calcified (hardened)
                     bone cells = osteocytes
                                                                                                    no haversian canal system
                                                                                                    no direct blood supply
                     matrix predominates; ~ 1/3rd organic and                                          ! nutrients and O2 by diffusion
                      2/3rd’s inorganic
                                                                                               all bone starts out as cartilage
                          matrix contains lots of collagen fibers

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        in bone the matrix is hardened (= ossified) by                                                 Anatomy of Skeletal System
          calcification (or mineralization)

        microscopic structure of cartilage:                                            Bone Markings: any bump, hole, ridge, etc on each
                                                                                        bone; eg.:
             chondrocytes in lacunae
                                                                                           Foramen: opening in bone – passageway for nerves and blood
                                                                                                  vessels
        kinds of cartilage:
                (all similar matrix with lots of collagen                                  Fossa: shallow depression – eg a socket into which another bone
                                                                                                    articulates
                fibers; differ in other fibers)
                                                                                           Sinus: internal cavity in a bone
             1. hyaline
                     most common                                                           Condyle: rounded bump that articulates with another bone
                       eg. covers articular surfaces of joints, costal cartilage
                            of ribs, rings of tracheae, nose                               Tuberosity: large rough bump – point of attachment for muscle

                                                                                           Spine: sharp slender process
             2. fibrous
                     mostly collagen fibers
                       eg. discs between vertebrae, pubic symphysis                    two main subdivisions of skeletal system:

             3. elastic                                                                    axial : skull, vertebral column, rib cage
                     also has elastic fibers
                        eg. external ear, eustacean tube
                                                                                           appendicular: arms and legs and girdles

                                                                                       The Axial Skeleton

                                                                                       A. Skull

                                                                                           most complex part of the skeleton

                                                                                           consists of facial and cranial bones

                                                                                               most bones are paired, not all
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                                                                                             in 4 of the bones making up the face
        bones joined at sutures
                                                                                             in life lined with mucous membrane to form sinuses

    1. Fontanels                                                                                  lighten bone, warm and moisten air

        ossification of skull begins in about 3rd month of                                   6 sinuses:
          fetal development                                                                                    frontal -2
                                                                                                               maxillary -2
                                                                                                               ethmoid -1
        not completed at birth!bones have not yet fused                                                        sphenoid -1

        gaps = fontanels                                                                 Examples of Paired Skull Bones:
                              frontal (anterior)
                              occipital (posterior)
                                                                                         5. Maxilla
                              2 sphenoid
                              2 mastoid
                                                                                                  cheek bones, upper teeth cemented to these bones
             at this stage skull is covered by tough membrane for protection
                                                                                                  hard palate: palatine process and palatine bones
             normally, bones grow together and fuse to form solid case around
                brain                                                                                 cleft palate ! when bones of palatine process of maxilla
                                                                                                         bones do not fuse properly
    3. Skull Cavities
                                                                                                               not only cosmetic effect
                                                                                                               can lead to serious respiratory and feeding problems in
        inside of skull contains several significant cavities:                                                   babies and small children
                                                                                                               today, fairly easily corrected
             cranial cavity – largest (adult – 1,300 ml); part of dorsal
                               body cavity
             orbits – eye sockets                                                        6. Temporal Bone
             nasal cavity                                                                         external auditory meatus - opening to ear canal
                                                                                                    leads to middle ear chamber
             buccal cavity
                                                                                                  ear ossicles:
             middle and inner ear cavities
                                                                                                      malleus           = hammer
    4. Paranasal Sinuses                                                                              incus             = anvil
                                                                                                      stapes            = stirrup
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    7. Mandible = lower jaw                                                                       very delicate and easily damaged by sharp upward blow to the
                                                                                                       nose
             largest, strongest bone of face
             articulates at temporal bone                                                                 can drive bone fragments through the cribriform plate
                                                                                                            into the meninges or brain itself

    Examples of Unpaired Skull Bones:                                                                     can also shear off olfactory nerves! loses of smell

    8. occipital bone                                                                    11. hyoid bone –                          single “U” shaped bone in neck just below
                                                                                                          mandible
             foramen magnum - large opening in base
               through which spinal cord passes                                                   suspended from styloid process of temporal bone

             occipital condyles - articulation of vertebral column                                only major bone in body that doesn’t directly articulate with
                                                                                                    other bones
    9. sphenoid bone –                               irregular, unpaired bone
                                                                                                  serves as point of attachment for tongue and several other
                                                                                                    muscles
             resembles bat or butterfly;

             “keystone” in floor of cranium                                          B. Vertebral Column
                     ! anchors many of the bones of cranium
                                                                                         main axis of body
             contains sinuses
                                                                                         flexible rather than rigid
             sella turcica – depression for the pituitary gland

                                                                                             permits foreward, backward, and some sideways
    10. ethmoid – irregular, unpaired bone
                                                                                                movement
             honeycomed with sinuses
                                                                                         divided into 5 regions:
             cribiform plate – perforated with openings which                                         cervical
                allow olfactory nerves to pass                                                        thoracic
                                                                                                      lumbar
             nasal conchae – passageways for air; filtering,                                          sacral
               warming, moistening                                                                    coccygeal

             crista galli – attachment of meninges
                                                                                         all but last two are similar in structure:
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        body                                                                                 sacroiliac joint – lots of stress
        spinous process
        vertebral foramen
        transverse process
                                                                                         Coccyx            (4-5, some fused):

        superior and inferior articular process
        intervertebral foramen between each pair                                             tailbone
        separated by intervertebral discs
                                                                                             painful if broken

Cervical             (7):                                                                    sometimes blocks birth canal, must be broken

    have transverse foramena
                                                                                         C. Ribcage
    1s t and 2nd are highly modified for movement:
                                                                                                                            manubrium
        atlas –   holds head up                                                              sternum                        body (=gladiolus)
             no body or spinous process                                                                                     xiphoid process
             “yes” movement of head
                                                                                             ribs: most joined to sternum by costal cartilages
        axis -- dens (odontoid process) – forms pivot
             “no” movement
                                                                                                          true ribs (7prs)

Thoracic (12):                                                                                            false ribs (5 prs)
                                                                                                               include floating ribs (2prs)
    distinguished by facets smooth areas for articulation of ribs

    each rib articulates at two places
      one on body of vertebrae
      one on transverse process


Lumbar              (5):

    short and thick spinous processes

    modified for attachment of powerful back muscles


Sacrum (5 fused):
    triangular bone formed from fused vertebrae

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Appendicular Skeleton                                                                        3. Forearm:
                                                                                                      very mobile; adds to flexibility of hand
A. Upper Extremeties
                                                                                                      consists of two bones: radius & ulna
    shoulder (=pectoral girdle)
    upper and lower arm                                                                               they are attached along their length by interosseous
                                                                                                        membrane
    wrist and hand
                                                                                                      ulna:
    1. Pectoral Girdle:
                                                                                                          main forearm bone
                                                                                                          firmly joined to humerous at elbow
             scapula & clavicle                                                                           large process = olecranon process, extends behind elbow
                                                                                                             joint
                 only attached to trunk by 1 joint (between sternum and
                   clavicle)                                                                                       acts as lever for muscles that extends forearm
                     scapula is very moveable – acts as almost a 4th segment                          radius:
                       of limb
                                                                                                          more moveable of two
                          scapula rides freely and is attached by muscles and                             can revolve around ulna to twist lower arm and hand
                               tendons to ribs but not by bone to bone joint

                          extensive flat areas of scapula are used as origins for            4. Hand:
                            arm muscles and trunk muscles
                                                                                                      attached by muscles mainly to radius provides great flexibility
                     clavicle is the most frequently broken bone in the body,
                        sometimes even during birth                                                   large # of rounded bones (carpals) provide flexibility

                                                                                                          carpals allow movement in all directions
    2. Upper Arm:
                                                                                                          metacarpals also rounded for flexibility
             Humerus: longest and largest bone of arm
                                                                                                          phalanges, not rounded, simple hinges for grasping
                 loosely articulates with scapula by head – glenoid cavity

                 large processes of scapula, acromium and coracoid

                     !have muscles which help to hold in place

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B. Lower Extremeties                                                                                     pubic symphysis: anterior joint of fibrous cartilage

                                                                                                              in women before birth it softens to allow expansion of
    number and arrangement of bones in the lower limb                                                            birth canal
      are similar to those of the upper limb
                                                                                                 as bipedal animals the pelvis must support most of the body
                                                                                                   weight
    in the lower limb they are adapted for weight
      bearing and locomotion, not dexterity                                                              !viscera bear down on pelvic floor

                                                                                                         ! pelvis is funnel shaped; yet must remain large enough
    pelvic girdle (pelvis, 2 coxal bones, sacrum, coccyx)                                                  for the birth canal
      thigh
      lower leg                                                                                  pelvis is easiest part of skeleton to distinguish between sexes
      feet
                                                                                        2. Upper Leg = Thigh
    1. Pelvic Girdle
                                                                                                 made up of single bone = femur; largest bone in body
             forms large basin of bone
                                                                                                 head fits in large deep socket = acetabulum of pelvis
                !receptacle for many internal organs
                                                                                                     great strength, less flexibility than humerous
             origin of thigh muscles and trunk muscles

             rigid connection to axial skeleton; strength, not flexibility                       kneecap = patella;

             large flaring portion = false pelvis                                                    a sesamoid bone = bones found where tension or pressure
                                                                                                        exists; eg thumb and large toe
             smaller actual opening = true pelvis
                                                                                                     in tendons at knee joint; does not articulate directly with
                 !actual space child must fit through in women                                          any other bone

             pelvis consists of a pair of innominate bones (= os coxae)                              acts as kind of a bearing
                  that articulate with sacrum                                                          !allows tendon to slide smoothly across knee joint

                 each innominate is produced by fusion of three bones:                               if patella is lost through accident or injury get
                                                                                                         ~30% loss of mobility and strength due to > friction
                     ilium   – upper, fan shaped
                     ischium – bottom                                                   3. Lower Leg
                     pubis   – front

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             consists of two bones: tibia and fibula

             tibia (=shinbone)                                                                                              Articulations
                 main bone, articulates with both femur and foot
                                                                                    Articulations = joints between bones
                          !more strength, less mobility
             fibula                                                                     hold bones together while usually allowing some
                                                                                          movement
                 small, offers extra support for lower leg and foot

                                                                                    can be classified by:
    4. Foot
             like hand, made of many bones                                              1. degree of movement
             thick angular bones; must support all the weight of the body
                                                                                        2. structure of the joint
             arches: strung with ligaments to provide double arches
                 = shock absorbers                                                  Degree of Movement
                     arches also furnish more supporting strength than any
                       other type of construction !more stability                       Synarthroses                      (=”joined together”, joint)

                     if ligaments and muscles weaken, arches are lost                                !immoveable
                         = flatfootedness = fallen arches,

                              ! more difficult walking, foot pain, back pain            Amphiarthroses (=on both sides, joint)

                     high heals redistribute the weight of foot!throw it                             !slightly moveable
                        foreward; ends of metatarsals bear most weight

                              !sore feet
                                                                                        Diarthroses (through a joining)

                                                                                                     !freely moveable

                                                                                    Structure of the Joint

                                                                                        Fibrous Joints

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                 articular surface of both bones                                                 Examples of the 3 kinds of articulations

                 joined by fibrous connective tissue                                             1. Immoveable (Fibrous) Joints
                                                                                                         eg. sutures
    Cartilaginous Joints
                                                                                                              – only in skull
                 articular surface joined by some kind of
                      cartilage (eg. fibrous or hyaline)                                                 eg. gomphoses

                                                                                                              -teeth in socket
    Synovial Joints
                                                                                                         eg. syndesmoses
                 articulation is surrounded by joint capsule                                                  - fibrous bands between two bones
                      and synovial membrane
                                                                                                              - distal tibiofibular joint
                              joint capsule
                              articular cartilage                                                2. Slightly Moveable (Cartilaginous)
                              joint cavity
                              synovial membrane                                                          eg. symphyses
                              synovial fluid
                              periosteum                                                                      -fibrocartilage pad or disc

                                                                                                              -midline of body
In general structure is correlated with function:
                                                                                                              -symphysis pubis
    therefore, three major kinds of joints:
                                                                                                              -intervertebral discs
        1. immoveable                                            ~          fibrous                      eg. synchondroses

        2. slightly moveable                                     ~          cartilaginous                     -hyaline cartilage joins two bones

                                                                                                              -epiphyseal discs; temporary
        3. freely moveable                                       ~          synovial
                                                                                                              -costal cartilage between ribs and sternum



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3. Freely Moveable (Synovial)                                                                                     !slow to repair
        most body articulations
                                                                                                                  tendons – specialized structures that attach
        provide for many different kinds of motion:                                                                         muscle to bone across joints

                 eg. uniaxial                                                                                              often enclosed by tendon sheath
                          hinge joint (fingers, toes, elbow)
                                                                                                                  ligaments – bind bones together across joints
                          pivot joints (head, radius at hand)

                 eg. biaxial                                                                                               more elastic than tendons

                          condyloid joints (metacarpals-phalanges                                                          hold joints in place
                          saddle joints (metacarpal-thumb)
                                                                                                                           limit their range of motion
                 eg. multiaxial
                                                                                                         Bursa
                          gliding joint (carpals, tarsals)

                          ball and socket joints (shoulder, hip)                                              synovial sacs spaced around joints between
                                                                                                                tendons or ligaments
        Includes tendons and ligaments
                                                                                                              cushion ! reduce friction
             both composed mainly of fibrous connective
               tissue                                                                                Exercise and Synovial Joints

                                                                                                         synovial fluid is warmed by exercise and becomes thinner
             consist of parallel strands of collagen fibers
                                                                                                              !this is more easily absorbed by articular cartilage
             continuous with periosteum and embedded in
                                                                                                                  !provides more effective cushion against compression
               bone
                                                                                                         this warmup and compression also helps to distribute nutrients
             rarely break but tear away from bone                                                           to cartilage cells (nonvascular tissue) and squeeze out
                                                                                                            metabolic wastes

             when mature have few cells                                                                           ! warm up is good for you
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                            Skeletal Physiology
                                                                                                     Physiology of Bone
Composition of Bone
                                                                                                     bone is active tissue:
bone is the densest tissue in the body
  ! only 20% water                                                                                       !5-7% bone mass/week
                                                                                                                  mature haversian canal systems are replaced up to 10x’s
bone has a grain just like wood:                                                                                    during a lifetime

    grain runs longitudinally for greatest strength                                                                       !equiv. of skeletal mass is replaced every 7 years

bone tissue consists of cells and matrix:                                                            most calcium in body is contained in teeth and skeleton

        cells: =osteocytes                                                                               ! acts as a mineral reservoir, esp for calcium, and
                                                                                                           phosphate
             cells that secrete the matrix
                                                                                                     calcium is used in body for:
        matrix:
                                                                                                             muscle contractions
                                                                                                             nerve impulses
                 2/3rd mineral salts (bone only)                                                             synapses
                        calcium & phosphorus                                                                 heart beat
                                                                                                             secretions
                                           (CaPO4, CaOH, CaCO3)
                                                                                                             blood clotting
                                           also Mg, Na, K                                                    cofactors for enzymes

                                           tends to accumulate metals:lead & radium                  a supply of calcium must be constantly available for all
                                                ! bone cancer, leukemia                                these activities
                 1/3rd collagen and proteins (cartilage and
                                                                                                         blood calcium homeostasis is maintained by
                        bone)
                                                                                                              dissolving or depositing bones via osteocytes
        mixture of organic and inorganic components allow
                                                                                                         cells = osteocytes ( in lacunae)
         bone to be strong without being brittle
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             two kinds of bone cells:
                                                                                                         epiphyseal cartilage disappears when bone has
                     osteoblasts                      bone forming cells                                      completed its growth (in length)
                          also works alongside osteoclasts to rework bone
                                                                                                     Bone Maintenance and Remodeling
                     osteoclasts                       bone destroying cells
                                                                                                     the skeletal system is strongest in early adulthood
                          very large cells produced by cell fusions
                            contain up to 300 nuclei
                                                                                                     bones continue to grow and remodel themselves
                          amoeboid movement                                                            throughout life

                          wraps around small section of bone
                                                                                                     bone growth in diameter occurs by combined action of
                            secretes enzyme to digest it
                                                                                                        osteoblasts and osteoclasts
Bone Formation                                                                                       even after bone growth has stopped, osteoblasts and
                                                                            st                         osteoclasts continue working
parts of skeleton begin to form in 1                                             few weeks of
  development                                                                                                in adult these opposing processes balance each
                                                                                                               other out so bone neither grows nor shrinks
        begins in fetus as cartilage template
                                                                                                     bone destruction is not always a pathological
Ossification = conversion of cartilage or other                                                        process:
   connective tissueinto bone
                                                                                                             a. bones constantly adapting to stresses
        in longbones ossificaton begins 3rd month of                                                                reaction to mechanical stresses
             development
                                                                                                                                   tension regions + chg
                                                                                                                                   compresed regions – chg
    centers of ossification in longbones:                                                                                          affects PTH activity


             begins in diaphysis                                                                                                strengthens weak areas

                 at birth additional centers in epiphyses                                                    b. old bone removed to reduce bulk
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                                                                                     Effects of Aging on Skeletal System
        c. minerals are added or removed from reservoir
                as Calcium is metabolized                                        Skeletal Changes from Childhood to Adult:

                          99% of body’s Ca++ is in bone                          A. infancy & childhood
                                   (1200-1400g vs 1.5g in blood)

                 two hormones involved - antagonists                                 change size, proportion,

                     PTH                                                             growth in length is cartilage of epiphyseal disc

                          !stimulates bone destruction (osteoclasts)                     growing faster than ossification proceeds

                     Calcitonin                                                      growth hormone plays major role

                          !stimulates bone formation (osteoblasts)                       ! stimulates cartilage

                 Ca++ deficiency:                                                    thyroid hormone
                          severe neuromuscular problems
                          hyperexcitability                                              ! proper proportions
                          loss of function
                                                                                                  head becomes proportionately smaller
                 Ca++ excess:                                                                     facial bones more prominent
                                                                                                  thorax more elliptical
                          Calcium deposits in blood vessels,                                      pelvis larger and wide
                            kidneys and soft organs                                               legs proportionately longer
                                                                                                  vertebral column develops two additional curves
                                                                                                     (already had thoracic and pelvic curves)
                                                                                                        cervical curve ~3mo; lifts head
                                                                                                        lumber ~1 yr; standing, walking


                                                                                 B. Puberty

                                                                                     sex hormones (estrogen & testosterone) stimulate
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                                                                                                  ! bone become brittle
             ossification
                                                                                         shaggy margins, spurs, joint problems
                          ! epiphyseal closure
                                                                                         cartilage keeps growing: big ears
    facial features develop rapidly

    also produce masculinizing and feminizing features of
        skeleton
                 male              – deep and funnel shaped;
                                    whole skeleton larger and heavier

                 female            – shallow, broader and flaring

C. Adulthood:

        Bone maintenance and remodeling

             bone destruction is not always a pathological
                process:

                     a. bones constantly adapting to stresses

                     b. old bone removed to reduce bulk

                     c. minerals are added or removed from
                        reservoir as calcium is metabolized

D. Old Age

    reabsorption outweighs growth

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                 Disorders of Skeletal System
                                                                                 2. Vertebral curvature
1. Fractures                                                                             normally spine has two “S” shaped curves

        repairs more slowly than skin; up to 6 months                                    provides flexibility and resilient support

    a. clot (hematoma) formation                                                         several types including:

             hours                                                                                 scoliosis – abnormal lateral curvature
             broken blood vessels, damaged tissues, bone cells die                                   may appear spontaneously
                                                                                                     or be result of polio, rickets or TB
    b. soft callus (fibrocartilage)
                                                                                 3. Osteoporosis
             days
             growth of new capillaries                                                   bones lose mass and become more brittle
             disposal of dead tissue
                                                                                         group of diseases in which bone reabsorption
    c. bony callus                                                                           outpaces bone deposition

             weeks                                                                       affects entire skeleton but esp
             spongy bone tissue grows around area and replaces                                spongy bone of vertebrae and neck of femur
                fibrocartilage
             join two pieces firmly together                                             esp in post menopausal women

    d. remodeling                                                                        sex hormones
                                                                                              stim bone deposition,
             months                                                                           decrease osteoclast activity
             dead portions of original area reabsorbed
             compact bone replaces spongy bone                                           menopause – sharp reduction in sex hormones
             ends are remodeled to blend in
             usually thickened area remains                                              esp post menopausal women (esp caucasian women)
             misset bones may heal crooked
             but weight bearing bones usually reassume proper shape                           by 70 yrs the average white woman has lost 30% of her bone
             elec current speeds calcification and repair                                       mass (some up to 50%)

                                                                                         not as drastic in men
    new synthetic materials may soon be useful in replacing missing                        bone loss begins ~60 yrs and seldom exceeds 25% loss
         bone
    also bone grafts                                                                     smoking also reduces estrogen levels
Human Anatomy & Physiology: Skeletal System; Ziser, Lecture Notes, 2010.4   33   Human Anatomy & Physiology: Skeletal System; Ziser, Lecture Notes, 2010.4   34




                                                                                         bony spurs may form as cartilage wears away !deform joint
        low body fat reduces estrogen production by ovaries in young                     interfere with movement, pain
          female runners and dancers

        most serious consequence is pathologic fractures
                                                                                 6. Rheumatoid Disease
          esp in hip, wrist and vertebral column
                                                                                         far more severe than OA
                                                                                         is an autoimmune attack against synovial membrane
        also, as bones become less dense they compress like
                                                                                         inflammation of synovial membranes and degeneration of
           marshmallows
                                                                                            cartilage
                                                                                         synovial membranes fill with abnormal tissue growth =
                 ! results in kyphosis ! exaggerated thoracic curve
                                                                                            granulation tissue
                     (widow’s hump, dowager’s hump)
                                                                                         may erode articular cartilage, bones and ligaments
        suggestions:                                                                     mainly small joints of body; wrists, ankles
          need good bone mass by 35 or 40                                                tends to flare up and subside periodically
          plenty of weight bearing exercise, esp before menopause                        affects women far more than men
                                                                                         typically begins between age 30 – 40
          good calcium uptake (850-1000 mg/d) early in life, esp 25-40
                                                                                         no cure, but can be slowed with steroids, cortisone, etc
          fluoridated water helps harden bones
          don’t smoke
          hormone replacement therapy only slows loss, doesn’t replace           7. Osteomyelitis
             lost bone
                     -No longer recommended, too dangerous                               any infection of bone, cartilage or periosteum
                                                                                         localized or general
4. Rickets                                                                               usually bacterial

        childhood disease: bowed legs, deformed pelvis,                          8. Ruptured (herneated) disc
        due to Vit D (or Ca++) deficiency during growing years
        body unable to absorb calcium from intestine                                     intervertebral discs pad vertebrae
        reduces calcification – bones stay soft                                          with age outer layer thins and cracks; inner layers less firm
                                                                                         extra pressure can cause rupture
5. Osteoarthritis                                                                        = herneated disc: pain, numbness, partial paralysis

        most common age change is degeneration of joints                         9. Gout
           =wear and tear arthritis
        rarely occurs before age 40; affects 85% of those over 70                        group of diseases characterized by elevated uric acid in blood
        as joints age get gradual softening and loss of articular cartilage              forms sodium urate crystals in synovial fluid causing severe pain
        bone formation at margin of articular cartilage                                  exacerbated by alcoholism
        as cartilage becomes roughened by wear, joint movements may
           be accompanied by crunching or cracking sounds (=crepitus)
        affects especially fingers, intervertebral joints, hips and knees        10. Bursitis
Human Anatomy & Physiology: Skeletal System; Ziser, Lecture Notes, 2010.4   35   Human Anatomy & Physiology: Skeletal System; Ziser, Lecture Notes, 2010.4   36
        inflammation of bursal sacs around joints
        fills with fluid
        usually caused by blow or friction
        =“housemaids knee”
        =“water on the knee”


11. Tendonitis
        inflammation, usually due to overuse

12. Achondroplastic Dwarfism

        spontaneous mutation of genes, not necessarily from parents
        long bones of limbs stop growing in childhood while growth of
              other bones is not affected
           ! results in short stature but normal sized head and trunk
        not same as pituitary dwarfism, only certain cartilage cells are
           affected

13. Polydactyly & Syndactyly
        too many or too few fingers and toes




Human Anatomy & Physiology: Skeletal System; Ziser, Lecture Notes, 2010.4   37
Subject:
H.A.P.
Semester:
First
Cource:
B pharm

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