Upload
aubrie-burns
View
230
Download
0
Tags:
Embed Size (px)
Citation preview
The Skeletal System The Skeletal System (Bones and Joints)(Bones and Joints)
Anatomy & Physiology IChapter 7
Bone as a TissueBone as a Tissueosteology – the study of bone
skeletal system - composed of bones, joints, cartilages, and ligaments◦form strong flexible framework of the
body◦cartilage – forerunner of most bones
covers many joint surfaces of mature bone
ligaments – hold bones together at the joints
tendons – attach muscle to bone
7-3
Functions of the SkeletonFunctions of the Skeletonsupport – hold the body up, supports
muscles, mandible and maxilla support teeth
protection – brain, spinal cord, heart, lungs
movement – limb movements, breathing, action of muscle on bone
electrolyte balance – calcium and phosphate ions
acid-base balance – buffers blood against excessive pH changes
blood formation – red bone marrow is the chief producer of blood cells
7-4
Bones and Osseous TissueBones and Osseous Tissue
bone (osseous tissue) - connective tissue with the matrix hardened by calcium phosphate and other minerals
mineralization or calcification – the hardening process of bone
individual bones consist of bone tissue, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue
continually remodels itself and interacts physiologically with all of the other organ systems of the body
permeated with nerves and blood vessels, which attests to its sensitivity and metabolic activity
The Matrix of BoneThe Matrix of Bone matrix of osseous tissue is, by dry weight, about one-
third organic and two-thirds inorganic matter organic matter – synthesized by osteoblasts
◦ collagen, carbohydrate – protein complexes, such as proteoglycans and glycoproteins
inorganic matter◦ 85% calcium phosphate (hydroxyapatite)◦ 10% calcium carbonate◦ other minerals (fluoride, sodium, potassium, magnesium)
bone is a composite – combination of two basic structural materials, a ceramic and a polymer◦ combines optimal mechanical properties of each component◦ bone combines the polymer, collagen, with the ceramic,
hydroxyapatite and other minerals◦ ceramic portion allows the bone to support the body weight,
and protein portion gives bone some degree of flexibility rickets – soft bones due to deficiency of calcium salts osteogenesis imperfecta or brittle bone disease –
excessively brittle bones due to lack of protein, collagen
Bone StructureBone StructureTypes of osseous (bone) tissueCompact bone - Dense outer layerSpongy (cancellous) bone - Honeycomb of
trabeculae Bone marrow
◦ Red marrow
◦ Yellow marrowBone membranes
◦ Periosteum
◦ Endosteum
Compactbone
Trabeculae
Spongy bone(diploë)
Structure of a Long BoneStructure of a Long BoneDiaphysis (shaft)
◦Compact bone collar surrounds medullary (marrow) cavity
◦Medullary cavity in adults contains fat (yellow marrow)
Epiphyses◦Expanded ends ◦Spongy bone interior ◦Epiphyseal line (remnant of
growth plate) ◦Articular (hyaline) cartilage
on joint surfaces Living Dried
Marrow cavity
Periosteum
Nutrient foramen
Compact bone
Spongy bone
Epiphysis
Epiphysis
Diaphysis
Articularcartilage
Epiphysealline
Red bonemarrow
Yellow bone marrow
Epiphysealline
Articularcartilage
Proximalepiphysis
Epiphysealline
Articularcartilage
Periosteum
Spongy bone
Compact bone
Medullarycavity (lined
by endosteum)
Compact bone
Diaphysis
Distalepiphysis
Structure of a Long BoneStructure of a Long Bone
Membranes of BoneMembranes of BonePeriosteum
◦ Outer fibrous layer
◦ Inner osteogenic layer
Osteoblasts (bone-forming cells)
Osteoclasts (bone-destroying cells)
Osteogenic cells (stem cells)
◦ Nerve fibers, nutrient blood vessels, and lymphatic vessels enter the bone via nutrient foramina
◦ Secured to underlying bone by Sharpey’s fibers
Membranes of BoneMembranes of BoneEndosteum
◦Delicate membrane on internal surfaces of bone
◦Also contains osteoblasts and osteoclasts
Yellowbone marrow
Endosteum
Compact bone
Periosteum
Perforating(Sharpey’s) fibers
Nutrientarteries
Structure of Short, Irregular, Structure of Short, Irregular, and Flat Bonesand Flat Bones
Periosteum-covered compact bone on the outside
Endosteum-covered spongy bone within
Spongy bone called diploë in flat bones
Bone marrow between the trabeculae
Compactbone
Trabeculae
Spongy bone(diploë)
Bone MarrowBone Marrowbone marrow – general term for soft tissue
that occupies the marrow cavity of a long bone and small spaces amid the trabeculae of spongy bone
red marrow (myeloid tissue)◦ in nearly every bone in a child
◦ hemopoietic tissue - produces blood cells and is composed of multiple tissues in a delicate, but intricate arrangement that is an organ to itself
◦ in adults, found in skull, vertebrae, ribs, sternum, part of pelvic girdle, and proximal heads of humerus and femur
yellow marrow found in adults◦ most red marrow turns into fatty yellow
marrow◦ no longer produces blood
Location of Hematopoietic Location of Hematopoietic Tissue (Red Marrow)Tissue (Red Marrow)Red marrow cavities of adults
◦Trabecular cavities of the heads of the femur and humerus
◦Trabecular cavities of the diploë of flat bones
Red marrow of newborn infants◦Medullary cavities and all spaces in
spongy bone
Microscopic Anatomy of Microscopic Anatomy of BoneBoneCells of bones
◦Osteogenic (osteoprogenitor) cells – give rise to osteoblasts Stem cells in periosteum, endosteum and
central canals ◦Osteoblasts – manufacture bone matrix
Bone-forming cells◦Osteocytes – maintain and repair existing
bone matrix Mature bone cells
◦Osteoclasts – breakdown (resorb) bone matrix Cells that break down and release minerals from
bone matrix
Microscopic Anatomy of Microscopic Anatomy of Bone: Compact BoneBone: Compact Bone
Haversian system, or osteon—structural unit◦Lamellae
Weight-bearing Column-like matrix tubes
◦Central (Haversian) canal Contains blood vessels and nerves
Compact bone tissue
Microscopic Anatomy of Microscopic Anatomy of Bone: Compact BoneBone: Compact BonePerforating (Volkmann’s) canals
◦At right angles to the central canal◦Connects blood vessels and nerves
of the periosteum and central canalLacunae—small cavities that
contain osteocytesCanaliculi—hairlike canals that
connect lacunae to each other and the central canal
Endosteum lining bony canalsand covering trabeculae
Perforating (Volkmann’s) canal
Perforating (Sharpey’s) fibers
Periosteal blood vesselPeriosteum
Lacuna (withosteocyte)
Lacunae
Lamellae
NerveVeinArtery
Canaliculi
Osteocytein a lacuna
Circumferentiallamellae
Osteon(Haversian system)
Central(Haversian) canal
Centralcanal
Interstitial lamellae
Lamellae
Compactbone
Spongy bone
Compact Bone Compact Bone
Lacunae
Lamellae
Nerve
Vein
Artery
Canaliculus
Osteocytein a lacuna
Centralcanal
Compact Bone Compact Bone
Hormonal Regulation of Bone Hormonal Regulation of Bone GrowthGrowthGrowth hormone stimulates
epiphyseal plate activityThyroid hormone modulates
activity of growth hormoneTestosterone and estrogens (at
puberty)◦Promote adolescent growth spurts◦End growth by inducing epiphyseal
plate closure
Bone DepositBone Deposit
Occurs where bone is injured or added strength is needed
Requires a diet rich in protein; vitamins C, D, and A; calcium; phosphorus; magnesium; and manganese
Bone ResorptionBone ResorptionOsteoclasts secrete
◦Lysosomal enzymes (digest organic matrix)
◦Acids (convert calcium salts into soluble forms)
Dissolved matrix is transcytosed across osteoclast, enters interstitial fluid and then blood
Control of RemodelingControl of RemodelingWhat controls continual
remodeling of bone?◦Hormonal mechanisms that maintain
calcium homeostasis in the blood◦Mechanical and gravitational forces
Hormonal Control of Blood Hormonal Control of Blood CaCa2+2+
The level of blood calcium (Ca2+) must be maintained (homeostasis)
Calcium is necessary for◦Transmission of nerve impulses◦Muscle contraction◦Blood coagulation◦Secretion by glands and nerve cells◦Cell division
Which hormones are responsible for maintaining blood calcium?
Hormonal Control of Blood Hormonal Control of Blood CaCa2+2+
Primarily controlled by parathyroid hormone (PTH)
Blood Ca2+ levels
Parathyroid glands release PTH
PTH stimulates osteoclasts to degrade bone
matrix and release Ca2+
Blood Ca2+ levels
When blood calcium levels fall, PTH is released causing blood calcium levels to increase.
Hormonal Control of Blood Hormonal Control of Blood CaCa2+2+
May be affected to a lesser extent by calcitonin
Blood Ca2+ levels
Parafollicular cells of thyroid release calcitonin
Osteoblasts deposit calcium salts
Blood Ca2+ levels
When blood calcium levels rise, calcitonin is released causing blood calcium levels to decrease.
Response to Mechanical Response to Mechanical StressStress
Wolff’s law: A bone grows or remodels in response to forces or demands placed upon it
Observations supporting Wolff’s law:◦ Handedness (right or left handed) results in
bone of one upper limb being thicker and stronger
◦ Curved bones are thickest where they are most likely to buckle
◦ Trabeculae form along lines of stress◦ Large, bony projections occur where heavy,
active muscles attach
Bone MarkingsBone MarkingsBulges, depressions, and holes
serve as◦Sites of attachment for muscles,
ligaments, and tendons◦Joint surfaces◦Conduits for blood vessels and
nerves
Bone Markings: Bone Markings: ProjectionsProjectionsSites of muscle and ligament
attachment◦ Tuberosity—rounded projection
◦ Crest—narrow, prominent ridge
◦ Trochanter—large, blunt, irregular surface
◦ Line—narrow ridge of bone
◦ Tubercle—small rounded projection
◦ Condyle – rounded projection
◦ Epicondyle—raised area above a condyle
◦ Spine—sharp, slender projection
◦ Process—any bony prominence
Bone Markings: Bone Markings: ProjectionsProjectionsProjections that help to form joints
◦Head Bony expansion carried on a narrow
neck◦Facet Smooth, nearly flat articular surface
◦Condyle Rounded articular projection
◦Ramus Armlike bar
Bone Markings: Depressions Bone Markings: Depressions and Openingsand OpeningsMeatus
◦ Canal-like passageway
Sinus◦ Cavity within a
boneFossa
◦ Shallow, basinlike depression
Groove◦ Furrow
Fissure◦ Narrow, slitlike
openingForamen
◦ Round or oval opening through a bone
The skeleton
Bones of the Axial Bones of the Axial SkeletonSkeletonTwo main groups of bonesAxial skeleton—80 bones of the
head and trunkAppendicular skeleton—126
bones of the extremities
Framework of the SkullFramework of the Skull
Cranial bonesFacial bonesInfant skull
Framework of the Skull, Framework of the Skull, cont’dcont’d
Cranial bones◦Frontal ◦Parietal ◦Temporal ◦Ethmoid ◦Sphenoid ◦Occipital
Framework of the Skull, Framework of the Skull, cont’dcont’dFacial bones
◦Mandible ◦Maxillae ◦Zygomatic ◦Nasal ◦Lacrimal ◦Vomer◦Palatine◦Inferior nasal conchae◦Ossicle◦Hyoid
Framework of the Skull, Framework of the Skull, cont’dcont’d
Infant skull◦Anterior fontanel
ZOOMING IN • What type of joint is between bones of the skull?
The skull
The skull, inferior view.
ZOOMING IN • What two bones
make up each side of the hard palate?
ZOOMING IN
• What is a foramen?
Floor of cranium, superior view.
The skull, sagittal section.
ZOOMING IN • Which is
the largest fontanel?
Infant skull, showing Infant skull, showing fontanelsfontanels
Framework of the TrunkFramework of the TrunkVertebral column
◦ Cervical vertebrae◦ Thoracic vertebrae◦ Lumbar vertebrae◦ Sacral vertebrae (sacrum)◦ Coccygeal vertebrae (coccyx)
Thorax◦ Sternum◦ Ribs
True ribs False ribs
◦ Manubrium◦ Clavicular notch◦ Sternal angle◦ Xiphoid process
The Vertebral Column The Vertebral Column (Spine)(Spine)
five vertebral groups◦7 cervical in the
neck◦12 thoracic in the
chest◦5 lumbar in lower
back◦5 fused sacral at
base of spine◦4 fused coccygeal
Cervical vertebrae
Thoracic vertebrae
Atlas (C1)Axis (C2)
C7
Lumbar vertebrae
Sacrum
Coccyx Coccyx
Anterior view Posterior view
T1
T12
L1
L5
S1
S5
Newborn Spinal CurvatureNewborn Spinal Curvature
spine exhibits one continuous C-shaped curve at birth
known as primary curvature
Adult Spinal CurvaturesAdult Spinal Curvatures s-shaped vertebral column
with four normal curvatures◦ cervical◦ thoracic◦ lumbar◦ pelvic
primary curvatures – present at birth◦ thoracic and pelvic
secondary curvatures – develop later◦ cervical and lumbar◦ lifting head as it begins to
crawl develops cervical curvature
◦ walking upright develops lumbar curvature
Cervical curvature
Thoracic curvature
Lumbar curvature
Pelvic curvature
C7T1
T12
L1
S1L5
C1
Abnormal Spinal CurvaturesAbnormal Spinal Curvatures from disease, paralysis of trunk
muscles, poor posture, pregnancy, or congenital defect
scoliosis – abnormal lateral curvature◦ most common◦ usually in thoracic region◦ particularly of adolescent girls◦ developmental abnormality in which
the body and arch fail to develop on one side of the vertebrae
kyphosis (hunchback) – exaggerated thoracic curvature◦ usually from osteoporosis, also
osteomalacia or spinal tuberculosis, or wrestling or weightlifting in young boys
lordosis (swayback) – exaggerated lumbar curvature◦ is from pregnancy or obesity
KeyNormalPathological
(b) Kyphosis (“hunchback”) (c) Lordosis
(“hunchback”)
(a) Scoliosis
General Structure of VertebraGeneral Structure of Vertebra body (centrum)
◦ mass of spongy bone that contains red bone marrow
◦ covered with thin shell of compact bone◦ weight bearing portion◦ rough superior and inferior surfaces
provide firm attachment for intervertebral discs
vertebral foramina◦ collectively form vertebral canal for spinal
cord vertebral arch
◦ composed of two parts on each side◦ pedicle – pillarlike and lamina - platelike
spinous process◦ projection extending from the apex of arch◦ extends posteriorly and downward
transverse process◦ extends laterally from point where pedicel
and lamina meet superior articular processes
◦ project upward from one vertebra and meets inferior articular processes from the vertebra above
facets◦ flat articular surfaces covered with hyaline
cartilage
Spinous process
Lamina
Pedicle
Body
2nd lumbar vertebra (L2)Anterior
Posterior
Superior articularfacet
Transverseprocess
Vertebral foramen
Vertebralarch
Nucleus pulposus
Anulus fibrosus
Intervertebral disc
Intervertebral Foramen and Intervertebral Foramen and DiscsDiscs
intervertebral foramen◦ when two vertebrae are joined
they exhibit and opening;◦ intervertebral foramen -
passageway for spinal nerves◦ inferior vertebral notch in the
pedicle of the upper vertebra◦ superior vertebral notch in the
pedicle of the lower vertebra
intervertebral discs (23)◦ pad consisting of:
nucleus pulposus - inner gelatinous mass
anulus fibrosus – outer ring of fibrocartilage
◦ bind vertebrae together◦ support weight of the body◦ absorb shock◦ herniated disc (‘ruptured’ or
‘slipped’ disc) puts painful pressure on spinal nerve or spinal cord
L1
L2
L3
Intervertebral disc
Spinous process
Superior articularprocess of L1
Inferior vertebralnotch of L1
Superior vertebralnotch of L2
Inferior articularprocess of L3
Intervertebralforamen
The first two cervical The first two cervical vertebrae: Atlas and Axisvertebrae: Atlas and Axis
Atlas and Axis Articulation
Dens
Axis of rotation
Atlas
Axis
Transverseligament
Atlantoaxial joint
ZOOMING IN • To what bones do the costal cartilages attach?
Bones of the thorax Bones of the thorax
Bones of the Appendicular Bones of the Appendicular SkeletonSkeleton
Two divisions UpperLower
The Upper Division of the The Upper Division of the Appendicular SkeletonAppendicular Skeleton
The shoulder girdle◦Clavicle (collarbone)◦Scapula (shoulder blade)◦Supraspinous fossa and infraspinous
fossa◦Acromion◦Glenoid cavity◦Coracoid process
The Upper Division of the The Upper Division of the Appendicular Skeleton, Appendicular Skeleton, cont’dcont’d
The upper extremity◦Humerus (arm bone)◦Medial and lateral epicondyles◦Trochlea◦Ulna and radius (forearm bones)◦Distal projection (styloid process)◦Olecranon◦Trochlear notch (semilunar notch)◦Carpal bones◦Metacarpal bones◦Phalanges (finger bones)
ZOOMING IN • What does the prefix supra mean? • What does the prefix infra mean?
The shoulder girdle and The shoulder girdle and scapulascapula
Appendicular Skeleton: Appendicular Skeleton: Lower Lower DivisionDivision
The pelvic bones◦ Ilium
Iliac crest Anterior superior iliac spine
◦ Ischium Ischial spine Ischial tuberosity
◦ Pubis Pubic symphysis Acetabulum Obturator foramen Ossa coxae
ZOOMING IN • What bone is nicknamed the “sit bone”?
The Pelvic BonesThe Pelvic Bones
Comparison of male and female pelvisComparison of male and female pelvis
The lower extremity◦ Femur
Greater trochanter Lesser trochanter Linea aspera
◦ Patella◦ Tibia (shin bone)
Medial malleolus◦ Fibula
Lateral malleolus◦ Tarsal bones
Calcaneus (heel bone)◦ Metatarsal bones◦ Phalanges
Appendicular Skeleton: Appendicular Skeleton: Lower Lower Division, cont’dDivision, cont’d
The right femur (thigh bone)The right femur (thigh bone)
ZOOMING IN • What is
the medial bone of the leg?
Tibia and fibula of the Tibia and fibula of the right legright leg
Disorders of BoneDisorders of Bone
Metabolic diseasesTumorsInfectionsStructural problems
Metabolic DisordersMetabolic Disorders
Characterized by a lack of normal bone formation or excess loss of bone tissue
Osteoporosis◦Osteopenia
Paget’s disease (osteitis deformans)
Osteomalacia (in children, rickets)
TumorsTumors
Two types found in bone tissueBenignMalignant
◦Osteosarcomas◦Chondrosarcomas
InfectionInfection
Two types found in bone tissueOsteomyelitis
◦Inflammation of the bone caused by pyogenic bacteria
Tuberculosis◦Pott disease (tuberculosis of the
spine)
Structural DisordersStructural Disorders
Curvatures of the spine◦Kyphosis (hunchback)◦Lordosis (swayback)◦Scoliosis
Cleft palateFlatfoot
FracturesFracturesTypes of fracturesClosedOpenGreenstickImpactedComminutedSpiralTransverseOblique
Skeletal Changes in the Skeletal Changes in the AgingAging
Bones undergo significant changesLoss of calcium saltsDecrease in proteinReduction in collagenLoss of heightDecrease in chest diameter
The JointsThe Joints
Classified by material between adjoining bones and by degree of movement permitted
Fibrous◦Synarthrosis (immovable)
Cartilaginous◦Amphiarthrosis (slightly movable)
Synovial◦Diarthrosis (freely movable)
More About Synovial More About Synovial JointsJointsBones are joined by other
structures in synovial jointsLigamentsJoint capsuleHyaline (articular) cartilageMedial meniscus and lateral
meniscusFatBursae
Structure of a synovial joint.Structure of a synovial joint.
Types of Synovial JointsTypes of Synovial Joints
Classified by types of movement they allow
Gliding HingePivotCondyloidSaddleBall-and-socket
Movement at Synovial Movement at Synovial JointsJointsFlexionExtensionAbductionAdductionCircumductionRotation
Movement at Synovial Movement at Synovial Joints, cont’dJoints, cont’dMovements characteristic of
forearm and ankle◦Supination◦Pronation◦Inversion◦Eversion◦Dorsiflexion◦Plantar flexion
Disorders of JointsDisorders of JointsMechanical disorders
◦Dislocation◦Sprain
Arthritis◦Osteoarthritis (degenerative joint
disease [DJD])◦Rheumatoid arthritis◦Septic (infectious) arthritis◦Gout
Disorders of Joints, cont’dDisorders of Joints, cont’dHerniated disk
Backache◦Vertebrae diseases◦Intervertebral disk disorders◦Supporting structure abnormalities◦Abdominopelvic disorders◦Lumbosacral joint strains
Arthroscopic examination of the kneeArthroscopic examination of the knee
End of PresentationEnd of Presentation