Exercise 7 classification and structure of bones and cartilages

resting zone

Area of cartilage on epiphyseal side of epiphyseal plate that is relatively inactive

Ramus

Armlike bar of bone

foramen

Round or oval opening through a bone

fossa

Shallow, basinlike depression in a bone, often serving as an articular surface

tubercle

Small rounded projection or process

trochanter

Very large, blunt, irregularly shaped process (the only examples are on the femur)

osteon

a central canal and all the concentric lamellae surrounding it or haversian system

Groove

a furrow in the bone

primary ossification center

a region where bone tissue will replace most of the cartilage

Perichondrium

acts like a girdle to resist distortion of the cartilage when the cartilage is subjected to pressure. also plays a role in cartilage growth and repair.

spongy bone

aka cancellous bone composed of small trabeculae(columns) of bone and lots of open space.

anatomist

an expert in anatomy; a dissector

process

any bony prominence

in rickets the bones

are not properly calcified

sutural bones

are tiny bones between cranial bones except for the patellas, the sesamoid and sutural bones are not included in the bone count of 206 because they vary in number and location in different individuals

gross anatomy of the typical long bone

articular cartilage, epiphysis, metaphysis, diaphysis

skeletal cartilages

articular cartilages costal cartilages laryngeeal cartilages trachea and bronchial cartilages nasal cartilages intervertebral discs external ear cartilage

longitudinal bone growth

at epiphyseal plates(growth plates) follows a predictable sequence and provides a reliable indicator of the age of children exhibiting normal growth. if problems of long-bone growth are suspected. ex: pituitary dwarfism, Xray fils are taken to view the width of the growth plates. an abnormally thin epiphyseal plate indicates growth retardation.

skeleton subdivisions

axial and appendicular

periosteal bud

blood vessels, nerves, red marrow elements, osteoblasts, and osteoclasts

sinus

bone cavity, filled with air and lined with mucous membrane

bone markings

bones display projections, depressions, and openings that serve as sites of muscle, ligament, and tendon attachment, as joint surfaces, or as conduits for blood vessels they are not smooth but scrred withan array of bumpos, holes, and ridges.

Unclassified bones

bones that do not fall into one of the preceding categories are classified as irregular bones

axial skeleton

bones that lie around the body's center of gravity

head

bony expansion carried on a narrow neck

cartilage of external ear

elastic cartilage

external ear and epiglottis are made of

elastic cartilage

medullary cavity

essentially a storage region for adipose tissue

long bones

femur, bones of the fingers(phalanges) are much longer than they are wide, generally consisting of a shaft with heads at either end. composed mostly of compact bone.

growth of long bone

occurs at epiphyseal plate

hypertrophic zone

older cartilage cells enlarge

bones can further be classified by

on basis of their relative gross anatomy into four groups: long, short, flat, irregular bones.

red marrow

produces red blood cells, found in marrow cavities. in adults; confined to the interior of the epiphyses, where it occupies the spaces between the trabeculae of spongy bone.

bone marking categories

projections processes that grow out from the bone and serve as sites of muscle attachment or help form joints; and depressions or cavities, indentations, or openings in the bone that often serve as conduits for nerves and blood vessels.

tracheal and bronchial cartilages

reinforce other passageways of the respiratory system

interstitial lamellae

remains of old osteons that broke down as bone grew and remodeled itself because remodeling is going on all the time so you see interstitial lamellae

concentric lamellae (compact bone)

rings of bone tissue surrounding central canal

Condyle

rounded articular projection, often articulates with a corresponding fossa

perforating canals (Volkmann's canals)

run at right angles to the shaft and connect the blood and nerve supply of the medullary cavity to the central canals.

Central (Haversian) Canal

runs parallel to the long axis of the bone and carries blood vessels, nerves, and lymphatic vessels through the bony matrix

intervertebral discs

separate and cushion the vertebrae

Diaphysis

shaft of a long bone smooth surface composed of compact bone

spine

sharp, slender, often pointed projection

classification of cartilage

skeletal cartilages have representations from each of the three cartilage tissue types: hyaline, elastic, and fibrocartilage.

Lacunae

small spaces between the lamellae which contain osteocytes arranged in concentric circles call concentric lamellae

facet

smooth, nearly flat articular surface

bony spicules

sockets of extraction sites fill with cancellous bone & overfills sockets

yellow marrow

soft, fatty material found in the medullary cavity of long bones

trabeculae

spongy bone has a spiky, open-work appearance, resulting from the arrangement of the trabeculae that compose it where as compact bone appears to be dense and homogeneous however microscopic examination of compact bone reveals that it is riddled with passageways carrying blood vessels, nerves, and lymphatic vessels that provide the living bone cells with needed substances and a way to eliminate wastes.

nasal cartilages

support the external nose

articular cartilage

which covers the epiphyseal surface in place of the periosteum. the glassy hyaline cartilage provides a smooth surface to minimize friction at joints.

if animal is still young and growing

you will be able to see the epiphysieal plate, a thin area of hyaline cartilage that provides for longitudinal growth of th bone during youth. once the long bone has stopped growing, these areas are replaced with bone and appear as thin, barely descernible remnant--the epiphyseal lines.

line

Narrow ridge of bone; less prominent than a crest

crest

Narrow ridge of bone; usually prominent

fissure

Narrow, slitlike opening

epicondyle

Raised area on or above a condyle

endochondral ossification process

1. blood vessels invade the perichondrium covering the hyaline cartilage model and convert it to a periosteum. 2. osteoblasts at the inner surface of the periosteum secrete bone matrix around the hyaline cartilage model, forming a bone collar. 3. cartilage in the shaft center calcifies and then hollows out, forming an internal cavity. 4. a periosteal bud (blood vessels, nerves, red marrow elements, osteoblasts, and osteoclasts) invade the cavity and forms spongy bone, which is remived by osteoclasts, thus producing the medullary cavity. this process proceeds in both directions form the primary ossification center. as bones grow longer, the medullary cavity gets larger and longer.

Depressions and Openings for passage of vessels and nerves

Foramen, Groove, fissure, notch, others; fossa, meatus, sinus.

tuberosity

Large rounded projection; may be roughened

elastic cartilage

can be envisioned as " Hyaline cartilage with more elastic fibers" much more flexible than hyaline cartilage tolerates repeated bending better. only the cartilages of the external ear and the epiglottis(which flops over and covers the larynx when we swallow) are made of this cartilage

meatus

canal-like passageway

proliferation zone

cartilage cells undergo mitosis

lacunae

chambers

costal cartilage

connects ribs to sternum

fibrocartilage

consists of rows of chondrocytes alternating with rows of thich collagen fibers. looks like a cartilage-dense regular connective tissue hybrid! has great tensile strength and can withstand heavy compression. use to construct intervertebral discs and the cartilages within the knee joints

articular cartilage

cover the bone ends at movable joints

hardness of long bone

due to the inorganic calcium salts deposited in tis ground substance. its flexibility comes from the organic elements of the matrix, particularly the collagen fibers.

Periosteum

fibrous membrane covering made up of dense irregular connective tissue, to view the bone surface. notice that many fibers of the periosteum penetrate into the bone. These fibers are called perforating collagen fiber bundles (Sharpey's fibers). Blood vessels and nerves travel through the periosteum and invade the bone.

osteogenic cells

found on the inner, or osteogenic, layer of the periosteum.

flat bones

generally thin, with two waferlike layers of compact bone sandwiching a thicker layer of spongy bone between them. althought the name flat bone implies a structure that is level or horizontal, many flat bones are curved. ex: the bones of the skull.

cartilaginous regions of the skeleton

have fairly limited distribution in adults.

surfaces that form joints

head, facet, condyle, ramus

most skeletal cartialges are composed of

hyaline cartilage

in ebryos the skeleton is predominantly made up of

hyaline cartilage in the adult, most of the cartilage is replaced by more rigid bone.

notch

indentation at the edge of a structure

cartilage consists only in

isolated areas as the external ear, bridge of the nose, larynx, trachea, joints, and parts of the rib cage

what happens as the bone grows in diameter on its external surface

it is constantly being broken down on its inner surface. thus the thickness of the compact bone layer composing the shaft remains relatively constant.

bones are conected at

joints or articulations

laryngeal cartilages

largely construct the larynx (voice box)

chondroblasts

lay down new cartilage matrix on the epiphyseal face of the epiphyseal plate, and it is eroded away and replaced by bone spicules on the diaphyseal face. this process continues until late adolescence, when the entire epiphyseal plate is replaced by bone.

long bone cylinder

like a long bone is one of the strongest structures for its mass

classification of bones

long, short, flat, irregular, sesamoid, sutural

Hyaline cartilage

looks like frosted glass when viewed by the unaided eye. provides strudy support with some resilience or "give"

compact bone

looks smoth and homogeneous

calcification zone

matrix becomes calcified; cartilage cells die; matrix begins deteriorating

osteocytes

mature bone cells are in lacunae (chambers) which are arranged in concentric circles called concentric lamellae around the central canal.

endosteum

membranous lining of the hollow cavity of the bone/ lines the shaft also covers the trabeculae of spongy bone and lines the central and perforating canals of compact bone. like the periosteum, the endosteum contains osteogenic cells that differenciate into osteoblasts

ossification zone

new bone forms

the skeleton

the body's framework constructed of two of the most supportive tissues found in the human body : cartilage and bone. besides supporting and protecting the body as an internal framework, the skeleton provides a system of levers with which the skeletal muscles work to move the body. the bones store lipids and many mineral ( the most important of which is calcium) red marrow cavities of bones provide a site fro hematopoieses (blood cell formation)

appendicualr skeleton

the bones of the arms and legs and the structures associated with them

epihysis

the end of the long bone. notice that it is composed of a thin layer of compact bone that encloses spongy bone.

cartilage tissues distinguished by

the fact that they contain no nerves and very few blood vessels. each cartilage is surrounded by a covering of dense irregular connective tissue, called a perichondrium( rather than a periosteum)

canaliculi

tiny canals radiating outward from a central canal to the lacunae of the first lamella and then form lamella to lamella. form a dense transportation network through the hard bone matrix, connecting all the living cells of the osteon to the nutrient supply. may need a higher-power magnification to see the fine canaliculi.

Skeleton composed of:

two basic kinds of osseous tissue that differ in their texture: companct bone and spongy

short bones

typically cube shaped and contain more spongy bone than compact bone tarsals and carpals are examples.

endochondral ossification

uses hyaline cartilage "bones" as a model for bone formation. except for the collarbones(clavicles), al bones of the body inferior to the skull form in the embryo by this process of endochondral ossification

irregular bones

vertebrae