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THE SKELETAL SYSTEM. I. BONE STRUCTURE & FUNCTION A.There are 206 bones in the body. A.FUNCTION 1.Support 2.Protection 3.Movement due to muscles 4.Blood.

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Presentation on theme: "THE SKELETAL SYSTEM. I. BONE STRUCTURE & FUNCTION A.There are 206 bones in the body. A.FUNCTION 1.Support 2.Protection 3.Movement due to muscles 4.Blood."— Presentation transcript:


2 I. BONE STRUCTURE & FUNCTION A.There are 206 bones in the body. A.FUNCTION 1.Support 2.Protection 3.Movement due to muscles 4.Blood formation aka hematopoesis 5.Electrolyte Balance stores and releases calcium and phosphate 6.Acid Base Balance Buffers blood by storing and releasing alkaline salts

3 Skeletal system is divided Into 2 parts: A.blood by storing and releasing alkaline salts Parts of the skeletal system include: bones (skeleton); joints,cartilage, & ligaments Axial Skeleton Appendicular Skeleton

4 IV. The Skeleton A.Organization 1.Axial Skeleton –Skull –Vertebral Column –Vertebrae –Ribs 2.Appendicular Skeleton –limbs –girdles

5 Spongy (cancellous) Spongy (cancellous)  Compact Bone Two types of Bone

6 3.Mature Bone Osseous Tissue B. Microscopic Anatomy

7 Lamellar bone Called Lamellar bone Two kinds of bone  Compact  Spongy (cancellous) 3. Mature Bone

8 Spongy (cancellous) contains trabeculae contains trabeculae contains spaces contains spaces

9 Dense, few spaces Dense, few spaces Haversian canals Haversian canals Concentric Lamellae Concentric Lamellae Compact Bone 3. Mature Bone

10 Osseous Vocabulary & Anatomy Osteon (Haversian System) is a unit of bone. Central (Haversian) Canal is an opening in the center of an osteon that carries bloodvessels & nerves.

11 Osseous Vocabulary & Anatomy Perforating (Volkman’s) Canal runs perpendicular to the central canal & carries blood vessels & nerves.

12 Osseous Vocabulary & Anatomy Lacunae are cavities holding the mature bone cells (osteocytes). Arranged in concentric rings.. Lamella are the concentric rings around the central canal that holds the lacunae

13 Osseous Vocabulary & Anatomy Canaliculi are the tiny canals radiating perpendicularly from the central canal through the lamella creating a transport system from nutrients.


15 Osseous Vocabulary & Anatomy Osteoblasts are young bone forming cells that cause the hard extracellular matrix to form. Osteoclasts are bone dissolving cells Osteocytes are mature bone cells.

16 Osteoblasts

17 Osteocytes Osteoclasts

18 Osteoblasts Osteoclasts Osteocytes

19 Name C, D & E D = Osteoblast E = Osteocytes C = Osteoclast

20 I. BONE STRUCTURE & FUNCTION 4 Shapes of Bone: –Long bones Have a shaft with heads at both ends & Contain mostly compact bone. –Short bones Generally cube- shape & contains mostly spongy bone. –Flat bones thin, flattened, usually curved & has thin layer of compact bone surrounding spongy bone. –Irregular bones Do not fit into other bone classification categories

21 Long bonesShort bones

22 Flat bones Irregular bones

23 Classify the bone types to the left

24 B. Structure Parts of Long Bone –Epiphyses AKA: head Contains red bone marrow Spongy bone and compact bone

25 B.Parts of a Long Bone Diaphysis: Shaft of bone Contains yellow bone marrow w/in medullary cavity Spongy and compact bone

26 Diaphysis of Long Bone Medullary cavity contains yellow marrow (fat & minerals) in adults.

27 B.Parts of a long bone Epiphyseal plate  Allows for growth in bone  Found only in children Articular Cartilage: Covers the epiphyses Made of hyaline cartilage Decreases Friction @ joint surfaces

28 B.Parts of a long bone Periosteum: outer covering of diaphysis Fibrous connective tissue membrane Sharpey’s Fibers: Secure periosteum to underlying bone Arteries: Supply bone cells w/nutrients

29 D. Membranes 1.Periosteum 1.Periosteum: a.The external covering of bone 2.endosteum: a.Found on internal bone surface b.covers trabeculae of spongy bone marrow cavities


31 II. BONE GROWTH & DEVELOPMENT A.Two Patterns of Bone Formation 1.Intramembranous bones –originate between sheet-like layers of connective tissues

32 II. BONE GROWTH & DEVELOPMENT A.Two Patterns of Bone Formation 2.Endochondral bones –begin as masses of hyaline cartilage that bone tissue later replaces.

33 II. BONE GROWTH & DEVELOPMENT B.Growth in Long Bones 1.grow by interstitial growth at epiphyseal plates a.rate of cartilage growth is balanced by replacement with bone b.end of growth as cartilage cells slow down division

34 Bone Growth in Long Bones


36 II. BONE GROWTH & DEVELOPMENT B.Growth in Long Bones 2. bones grow in width by appositional growth a.Osteoblasts in periosteum: secretes bone matrix b.Osteoclasts in endosteum: removes bone matrix (a little slower)

37 Appositional Growth –New bone forms at ridges around blood vessels –Periosteum becomes endosteum

38 – New lamella formed – More bone added forming osteon Appositional Growth

39 II. BONE GROWTH & DEVELOPMENT C.Hormones 1. growth hormone from pituitary: stimulates growth in childhood a.Gigantism: excessive growth hormone b.dwarfism: not enough growth hormone or thyroid hormones

40 II. BONE GROWTH & DEVELOPMENT C.Hormones 2. thyroid: regulates activity of growth hormone 3. sex hormones: promote growth spurt, induce epiphyseal plate closure estrogen: maintains bone density

41 III. Bone Maintenance & Repair A.Bone remodeling: 1.Life long process 2. Local areas of bone are destroyed and rebuilt 3. Repairs microdamage caused by normal wear and tear


43 B.Fractures 1. Simple 1. Simple bone breaks cleanly, does not break through skin

44 B.Fractures 2. Compound 2. Compound broken ends protrude through the skin, risk of bone infection

45 B.Fractures 3. Greenstick 3. Greenstick Greenstick: (children) Does not break completely




49 Impact Fx of distal radius & ulna @ Epiphyseal Line

50 Facial Comminuted Fx

51 Tibial Oblique Fx





56 C. Repair Hematoma forms 1. Hematoma forms 2. Spongy bone forms in area of hematoma forming a soft callus 2. Spongy bone forms in area of hematoma forming a soft callus III. Remodeling and Repair

57 C. Repair Osteoblasts lay down new bone matrix 3. Osteoblasts lay down new bone matrix converting the soft callus into a hard callus of spongy bone 4. The boney callus is remodeled to form a permanent patch 4. The boney callus is remodeled to form a permanent patch

58 Bone healing occurs in stages: –fracture –granulation –callus –lamellar bone –normal contour III. Types of Bone Repair

59 III. Calcium Homeostasis A.Blood Ca 2+ Level 1.Has a very narrow range 2. Ca 2+ Required for –For normal muscle contraction –Nerve impuses

60 III. Calcium Homeostasis A.Blood Ca 2+ Level 3.Abnormal levels –Hypocalcemia causes marked jitteriness and convulsive seizures

61 III. Calcium Homeostasis A.Blood Ca 2+ Level 3.Abnormal levels –Hypercalcemia the most common life- threatening metabolic disorder associated with cancer

62 III. Calcium Homeostasis B.Bone’s Role 1.Major storage site for calcium 2.Calcium moves –Into bone as osteoblasts build new bone –Out of bone as osteoclasts break down bone

63 III. Calcium Homeostasis C.Bone, Calcium and Hormones 1.Parathyroid Hormone – Increases blood Ca 2+ levels 2.Calcitonin Decreases blood Ca 2+ levels

64 D. Homeostatic Imbalances OsteopeniaOsteopenia – Inadequate ossification OsteoporosisOsteoporosis – Bone absorption outpaces deposition – Fractures common – More common in elderly women III. Calcium Homeostasis

65 RicketsRickets – Lack of vitamin D or calcium during growth – Bowed legs – Deformed pelvis D. Homeostatic Imbalances Rickets

66 Osteosarcoma – Bone cancer – Usually between ages 10-25 – Survival rate is about 50% with amputation D. Homeostatic Imbalances

67 Bone spurBone spur – Abnormal projection at one site of bone due to overgrowth – Common in aging bones D. Homeostatic Imbalances

68 Bone Markings Bony markings are the surface features of a bone. They are sites of attachments for muscles, tendons & ligaments. They can serve as passage ways for nerves & blood vessels. There are 2 Categories of Bony Markings –Projections & processes – outward growths on the bone surface. –Depressions or cavities – indentations on the surface of the bone.

69 C.Bone Markings – 1. Kinds

70 For muscle attachment For formation of a joint To allow blood vessels or nerves to pass through Articulating Surfaces Openings Depressions & Enlargements 1. Kinds

71 C.Bone Markings – 2. Articulating surfaces A rounded projection set off from the body of a bone by a constriction (the neck) ex. head of femur Head

72 C.Bone Markings – 2. Articulating surfaces Condyle Any large articulating surface, may be concave or convex

73 C.Bone Markings – 2. Articulating surfaces A smooth, flat surface, generally small Facet

74 C.Bone Markings – 2. Articulating surfaces A shallow depression Fossa

75 C.Bone Markings – 3. Enlargements & Processes generic term for bone projection that serves as a point for attachment of other structures Process

76 C.Bone Markings – 3. Enlargements projection or swelling to the side of or above a condyle Epicondyle

77 C.Bone Markings – Spine a sharp, slender projecting process 3. Enlargements

78 C.Bone Markings – a small rounded projection Tubercle 3. Enlargements

79 C.Bone Markings – a large rounded roughened projection 3. Enlargements Turberosity

80 C.Bone Markings – 3. Enlargements Trochanter a large blunt projection

81 C.Bone Markings – 3. Enlargements a prominent border or ridge Crest

82 C.Bone Markings – 3. Enlargements A major branch or division off of the main body of a bone Ramus

83 C.Bone Markings – 4. Openings

84 C.Bone Markings – 4. Openings Canal like opening Meatus

85 C.Bone Markings – 5. Depressions A shallow groove Sulcus

86 C.Bone Markings – 5. Depressions A very shallow groove Fovea

87 C.Bone Markings – 5. Depressions A deep groove Fissure

88 Axial Skeleton Forms the longitudinal part of the skeleton. Divided into 3 parts: Skull Vertebral Column Bony Thorax

89 The Skull The skull is divided into 2 parts: Cranium Facial Bones The cranial bone joints are called sutures. Only the mandible is attached by a freely movable joint.

90 Lateral view of the Skull

91 Frontal view of the Skull

92 Transvers section of Inferior, Internal Skull

93 Inferior, External view of Skull

94 Sinuses The sinuses are hollow portions of bone within the skull surrounding the nasal cavity. They lighten the face/skull, act as resonance chambers & amplify the voice.

95 The Hyoid Bone  The only bone in the body that does not articulate w/another bone.  It serves as a moveable base for the tongue.

96 The Fetal Skull The fetal skull is large compared to the infant’s total body length. Fontanels are fibrous membranes connecting the cranial bones The fontanels allows the brain to grow. The fontanels converts to bone within 24 months after birth.

97 The Vertebral Column  The Vertebrae are separated by intervertebral discs made of fibrocartilage, connective tissue.  The spine has a normal “S” curvature.  Each vertebrae is given a name according to its location.

98 Bony Thorax Made of 3 parts: Sternum Ribs Thoracic vertebrae The bony thorax forms the rib cage that protects the thoracic internal organs.

99 The Appendicular Skeleton Includes the: Appendages (limbs) Pectoral Girdle Pelvic Girdle

100 Pectoral – Shoulder Girdle Made of 2 bones: Clavicle aka collarbone Scapula aka shoulder blade The pectoral girdle allows the upper limb to have free range of movement

101 Pectoral – Shoulder Girdle

102 Pectoral Girdle – Posterior View

103 Upper Extremity Bones Includes the: Humerus (upper arm bone) Radius (thumb side of forearm) Ulna (pinki side of forearm) & the Hand Anterior Humerus Posterior Humerus

104 Upper Extremity Bones The distal head of the radius is larger than the proximal The proximal head of the Ulna is larger than the distal.

105 Upper Extremity Bones The Hand includes: Carpals – short bones of the wrist. Metacarpals – long bones of the palm of the hand. Phalanges (Digits) – Proximal, Middle, Distal fingers.

106 Pelvic Girdle Made of the Coxal Bone (hip) which is 3 bones fused together: Ilium Ischium Pubic Bone The total weight of the upper body sits on the pelvis. The pelvis protects the reproductive organs, urinary bladder, & part of the large intestine


108 Lateral View of Pelvis

109 B. Male vs. Female Skeleton - Pelvis a.spines farther apart in male b.hole in ischium: smaller and triangular in female c.angle across pubic symphysis = pubic arch: less than 90° and more sharply angled in male d.distance between ischia larger in female

110 Male & Female Pelvic Differences

111 Lower Extremity Anterior Femur View Posterior Femur View The lower extremity is made of: Pelvis Femur (thigh) Tibia (shin) Fibula Foot

112 Lower Extremity The flat superior portion of the tibia is called the Tibial Plateau. The distal head of the tibia is called the medial malleolus while the distal head of the fibula is called the lateral malleolus

113 Lower Extremity The Foot is made up of the : Tarsals – short bones of foot Metatarsals – long bones of foot Phalanges (Digits)- long bones of the toes

114 The Arches The bones of the foot make up 3 arches. The 2 long arches are the lateral & medial longitudinal arches. The arch across the foot is the transverse arch.

115 Joints Joints are where 2 or more bones come together. Joint Functions: Holds bones together. Allows for mobility. Classified either Functionally or Structurally.

116 Joint Functional Classification Synarthrosis – immovable joints These joints permit no movement. Certain fibrous joints fall into this category. Amphiarthrosis – slightly moveable joints. These joints permit only a little bit of movement. Some cartilaginous and fibrous joints are in this category. Diarthroses – freely movable joints. These joints permit a variety of movements. Synovial joints fall into this category.

117 Joint Structural Classification Fibrous Joints – immovable joints. Formed by dense fibrous connective tissue Cartilaginous Joints – slightly moveable joints. Formed by cartilage Synovial Joints – freely movable joints. Formed by a synovial capsule

118 Joint Structural Classification Fibrous Joints Exaples: Sutures of Skull Syndemoses – Allows slightly more movement than sutures Medial Mallelous Lateral Mallelous

119 Joint Structural Classification Cartilaginous Joints Examples: Pubic Symphysis Intervertbral joints

120 Joint Structural Classification Synovial Joints: Bones are separated by a joint cavity & surrounded by a fibrous capsule. Synovial fluid fills the joint cavity/capsule. Ends of bones covered w/hyaline cartilage. Ligaments reinforce these joints.

121 Structures associated w/ Synovial Joints Bursa – flattened fibrous sacs filled w/synovial fluid. Tendon Sheath – Elongated bursa/membrane that wraps around a tendon to hold it together & protection.

122 Types of Synovial Joints Ball-and-socket joint Hinge joint Pivot joint Gliding or Plane joint Saddle joint Condyloid or Ellipsoid joint

123 Types of Synovial Joints Gliding or Plane joint –allows a wide range of side-to-side movements. Ex. Carpals & Tarsals Hinge joint - permit an angular motion along one plane, which is similar to the opening and closing of a door. Ex. Knee, elbow, PIP, MIP, DIP joints. Pivot joint – This allows a rotation similar to the turning of a dial. Ex. Radius pivots w/ulna.

124 Types of Synovial Joints Ball-and-socket joint –produce a wide array of movements. Ex. Hip & shoulder Saddle joint – joints resemble a saddle in which one bone’s articular surface rocks back and forth upon another. Ex. Metacarpal & carpal or Metattarsal & tarsal. Condyloid or ellipsoid joint –a ball-like articular surface rests against the curve-shaped end of another articular surface. This articulation allows a circular or elliptical pattern of motion. EX. Metacarpal & phalange

125 Joint Homeostatic Imbalances Bursitis – inflammation of the bursa usually due to trauma or friction Tendonitis – inflammation of the tendon usually due to overuse.

126 Joint Homeostatic Imbalances Arthritis – inflammation or degeneration of a joint. It’s the most widespread & crippling disease in the US. There are over 100 different types. Osteoarthritis - Most common type, due mostly to aging.

127 Joint Homeostatic Imbalances Rheumatoid Arthritis – an autoimmune disease where the body sees it’s joints as a foreign threat & will try to destroy them. Symptoms are bilateral joint pain & can lead to deformities. Gouty Arthritis – inflammation caused by deposits of uric crystals from the blood. Typically occurs in big toe. Usually due to diet.

128 That’s All Folks!

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