Bones, Cartilages and Joints

Objectives1. Determine the structure of the bones 1.1 Classify bones as to size and shape 1.2 Contrast compact from spongy bone 1.3 Locate the axial and appendicular bone 1.4 Identify the parts of long bones 1.5 List the functions of the bones 1.6 Give the types of bone formation 1.7 Discuss the process of bone healing

2 Determine the types of cartilage 2.1 Name the composition of the intracellular substance 2.2 Identify the histologic features of each type 2.3 Give the functions of each type 3. Describe the different types of Joints 3.1 Cite locations of joints 3.2 Demonstrate joint movements4. Identify some abnormalities in bones and joints

Tissues Epithelial Connective > Bone > Cartilage > Fibrous connective tissue > Blood Muscle Nerve

BonesComposition Cells: osteoblasts, osteoclasts, osteocytes Collagen fibers - to withstand shearing forces Dense mineralized ground substance: inorganic salts of calcium and phosphate = hydroxyapatite - for weight bearing

Bone cells

Functions of bones

Description

Movement Maintain or change position of body parts by interacting with skeletal muscles

Protection Enclose and protect the brain, lungs, and other organs

Support Support and anchor musclesMineral storage

Serve as a depot for storing and withdrawing mineral ions; indirectly helps maintain body fluids and support metabolic activities

Blood cell formation

Site for production of red blood cells and other blood cells

Types of bonesAccording to Density: compact and spongy Size and shape: long, short, flat & irregular Location: axial and appendicular

axial

appendicular

Types of bones according to size and shape1. Long = bones of the upper and lower

extremities2. Short = bones of the wrist and ankle3. Flat = clavicle, sternum, scapula and pelvis4. Irregular = vertebrae and facial bones

Long bones

Parts of Long Bones

Spongycompact

HumerusRadiusUlnaMetacarpalsPhalangesFemurTibiaFibulaMetatarsalsToes

Bone density Spongy bone - cancellous - consists of trabeculae - found within the epiphysis and metaphysis

Compact bone – cortical - usually found on the bone surface - making up most of the diaphysis

Organization of lamella in compact bone1. Haversian system – osteons - long cylinders running parallel to the long axis of the diaphysis2. Interstitial lamella3. Outer and inner circumferentil lamellae

Short bones = resemble blocks

Flat bones Composed of 2 thin plates of compact bones with

central region of spongy bone Skull bones, scapulae, ribs, sternum and pelvic

bones

Clavicle

Ribs

Irregular bonesPatella

Blue: Vomer (1) Yellow: Maxilla (2) Purple: Mandible (1) Pink: Nasal bones (2) Red: Palatine bones (2) Bright blue: Lacrimal bones (2) Dark green: Zygomatic bones (2) Bright green: Inferior nasal concha (2)

Bone formation

Intramembranous ossification

Endochondral ossification

Epiphyseal Plate

Bone remode

Wolff’s Law

Bone formation after fracture

Cartilage Supporting connective tissue with tensile strength Composition of ground substance > chondroitin sulfate > keratin sulfate > chondronectin > collagen: Type I = fibrocartilage Type II = hyaline and elastic no blood and nerve supply

Produced by chondroblasts to become chondrocytes

• Growth of Cartilage - Appositional growth results in outward expansion due to the production of cartilage matrix on the outside of the tissue - Interstitial growth results in expansion from within the cartilage matrix due to division of lacunae-bound chondrocytes and secretion of matrix

Types of cartilage

1. Hyaline - most common, found in

the ribs, nose, larynx, trachea - a precursor of bone2. Fibro - is found in vertebral

discs, joint capsules, ligaments

3. Elastic - is found in the external ear, and epiglottis

Hyaline cartilage• consists of living chondrocytes

situated far apart in fluid-filled lacunae

• contains a number of collagenous fibers

• occurs in trachea, the larynx, the tip of the nose, in the connection between the ribs and the breastbone

• provides a sliding area which reduces friction

Elastic cartilage has interlacing fibers contains many yellow elastic

fibers lying in solid matrix found in the epiglottis,

external ear, and eustachian tube

maintains the shape of a structure while allowing great flexibility

Fibrous cartilage dense collagen fibers and limited amount of ground substance chondrocytes are between the bundles of collagen has great tensile strength predominates in body areas that bear great

amounts of weight Found in the pubic symphysis.skull bones, and

disks between the vertebrae, in the tendonous and ligamentous insertions

Functions of fibrocartilage:1. Shock absorbers – cartilage between the

adjacent vertebrae while we run or walk

2. Provides sturdiness without impeding movement

- forms a firm joint between bones but still allows for a reasonable degree of movement

3. Deepens sockets – in articular cavities (such as the ball-and-socket joints in the hip and shoulder regions) white fibrocartilage deepens the sockets to make dislocation less possible

Characteristic

Cartilage Bone

Ground substance component

Chondroitin sulfate, keratin sulfate, chondro-nectin, no mineral component

Chondroitin sulfate, keratin sulfate, osteocalrin, osteo-pontin, sialoprotein, hydroxyapatite, citrate, carbonate

Collagen types

Type I fibrocar-tilageType II hyaline & elastic

Type I

Blood vessels

Absent, nutrient via diffusion

Present

Nerves Absent PresentRepair (regene-ration capacity)

Low High

Mitosis Chondroblasts YesChondrocytes Yes

Osteoprogenitor YesOsteoblasts NoOsteocytes No

Communication

No junctions between chondrocytes

Gap junctions between osteocytes

Hormonal influence

T3, T4, testos- terone, GH, cortisone, estradiol

PTH, Calcitonin, GH, Estrogens, Androgens

Joints Articulation Where bones come in contact with each other

Basic types of joints 1. those that have little or no movement a. Synarthroses - immovable b. Amphiarthroses - semimovable 2. those that are freely movable = Diarthroses

Joints that restrict movement1. Fibrous joints – bones are joined together by

strong fibrous tissues = Synarthroses a. Sutures b. Syndesmoses c. Gomphoses2. Cartilaginous joints – bones are joined together by cartilaginous material = Amphiarthroses a. Symphysis b. Synchrondroses

Sutures

Syndesmoses Between radius and

ulna

Between tibia and fibula

Gomphoses Between the root of tooth and jaw (upper = maxilla and lower = mandible)

Amphiarthroses Slightly movable joints Consists of two adjacent bone separated

by substantial amount of hyaline cartilage

Some cases bones are separated by ligaments

Symphysis pubis Intervertebral discs

Manubriosternal joint

Synchondrosis joint

Sacroiliac joint

Joints that allow movement Diarthroses Synovial joints – 2 bones encased within a cavity Architecture of synovial joints 1. surface where bones come in contact and move against each other is covered by articular or hyaline cartilage 2. surrounded by a strong fibrous joint capsule 3. contains joint cavity within the fibrous capsule 4. non epithelial synovial membrane secretes synovial fluid

Movements by synovial joints:- Axis of motion: = Nonaxial - slipping movements = Uniaxial - movement in one plane; phalanges, radius/ulna, femur/tibia = Biaxial - movement in two planes; occipital bone/atlas = Multiaxial - movement in three planes; scapula/humerus, and coxal bone/ femur

Types of synovial joints1. Plane or gliding2. Hinge3. Pivot4. Condyloid5. Saddle6. Ball and socket

plane

condyloid

Bursa Closed fluid-filled sac Lined with synovial membranes Commonly found between the skin and bony prominences Assist the movement of tendons that pass over bones

Joint movements Flexion – Extension Abduction – adduction Pronation – supination Median rotation – lateral rotation Elevation – depression Protraction – retraction Dorsiflexion – plantar flexion Eversion – inversion

Fracture – discontinuity with the anatomy of boneSprain - stretching/tearing of a ligament

Dislocation - (luxation), bones forced out of their normal positionBursitis - inflammation of bursa

Arthritis - inflammatory or degenerative disease; synovial membrane thickens, fluid production decreases, increase in friction and pain

Types of arthritis:• Osteo arthritis - degenerative• Rheumatoid arthritis - autoimmune• Gouty arthritis - uric acid

accumulation

Synovitis - inflammation of synovial membrane

Tendinitis - inflammation of tendon sheaths

Signs and symptoms of arthritispainswellingstiffnessfatiguefever rashes lumps under the skin limitation of body movement

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