anatomy lecture unit 2

chapters: 6, 7, 8, 9

where is cartilage found?

articular cartilage (nose and joints), ear, sternal cartilage, intervertebral discs, pubic symphysis, respiratory tubes, epiglottis, and articular discs

what are the three types of cartilage?

hyaline, elastic, and fibrocartilage

what do all three types of cartilage contain?

chondrocytes, abundant cellular matrix, and lacuna

what is the function of hyaline cartilage?

the most abundant, resists compression due to large amounts of H20

what does hyaline cartilage contain?

inside matrix will only be collagen fibers, chondrocyte in lacuna

where is hyaline cartilage found in?

articular cartilage, sternal cartilage, holds airways open in respiratory system

what is the function of elastic cartilage

tolerates repeated bending

what does elastic cartilage contain

contains elastic and collagen fibers, condrocytes in lacuna, gelatinous ground substance

where is elastic cartilage found

epiglottis(allows food to go into esophagus), ear(allows us to hear), and auditory tube(voice box —> determines pitch)

what does fibrocartilage contain

thick collagen fibers that surround the chondrocyte(dense irregular connective tissue), strongest cartilage

what is the function of fibrocartilage

resists compression and pulling forces

where is fibrocartilage found

intervertebral discs(cushions) and articular discs between joints(wrist, TMJ/jaw, meniscus ← biggest)

what are the functions of bones?

support(withstand gravity), movement(tendons), protection(of bones and organs), mineral storage(vitamin C), blood cell and fat storage(red bone marrow, yellow marrow in long bones), and energy metabolism

what are the classifications of bones?

long, short(sesamoid), flat, irregular, and sutural

which bone markings are sites of muscle and ligament attachment

tubercle, tuberosity, trochanter, crest, line, epicondyle, spine, and process

which bone markings are surfaces that form joints

heads, facets, and condyles

which bone markings are depressions and openings

foramen, groove, fissure, notch, fossa, meatus, and sinus

what is a tuberosity

large rounded projection; may be roughened

what is a trochanter

very large, blunt, irregularly shaped process(the ONLY examples are on the femur)

what is a tubercle

small rounded projection or process

what is a crest

narrow ridge of bone; usually prominent

what is a line

narrow ridge of bone; less prominent than a crest

what is an epicondyle

raised area on or above a condyle

what is a spine

sharp, slender, often pointed projection

what is a process

any bony prominence

what is a head

bony expansion carried on a narrow neck

what is a facet

smooth, nearly flat articular surface

what is a condyle

rounded articular projection, often articulates with corresponding fossa

what is a foramen

round or oval opening through a bone

what is a groove

furrow

what is a fissure

narrow, slitlike opening

what is a notch

indentation at the edge of a structure

what is a fossa

shallow basinlike depression in a bone, often serving as an articular surface, like a bowl

what is a meatus

canal-like passageway

what is a sinus

cavity within a bone, filled with air and lined with mucous membrane

compact vs spongy bone location

compact bone is on the outside of the bone, spongy bone is in the interior

what is the diaphysis

the shaft of bone

what is the epiphysis

proximal & distal epiphysis, ends of bone

what is the epiphyseal line

remnants of growth plate

what is the periosteum

dense irregular connective tissue, is the osteogenic layer with osteoblasts and osteoclasts, outside lining of bone

where is articular cartilage

at ends of bone/ at the epiphyses, arond joints & allows bone to grow in length

where is the endosteum

within the bone

what is found within the spongy bone/diploe

trabeculae

what is the organic bone composition?

mostly collagen(allows bones to not snap, but still bendy), produced by osteoblasts, contributes to the flexibility and tensile strength that allow bone to resist bending and twisting. approximately 35% of the bone weight is due to the organic composition.

what is the inorganic(hydroxyapatites ← cement of bone) bone composition

calcium phosphate, contributes to bone being hard and resisting compression forces; however torsion breaks bones easily

what are the bone cells types

osteogenic cell(stem cell, turns to osteoblast or osteoclast), osteoblasts(osteoid, build, extracellular matrix of bone), osteocytes(retired osteoblast, gives nutrients), and osteoclasts(PTH role, remodels bone)

what are the structures found in the histology of compact bone

osteon(haversion system, the whole circle), lamellae(rings/osteoid/fluid), central canal(haversion canal, center circle), perforating canals(Volkmann’s canal, 90 degree projections which link osteons together), lacunae(houses osteocytes and osteoblasts), canaliculi(links osteocytes, nutrients spread), circumferential lamellae(hold all osteons together)

when does bone ossification start?

the 8th week of embryo development

what is intramembranous ossification

bone formed from fibrous membrane; skull and clavicle

what is endochondral ossification

bone from hyaline cartilage replaced(everything other than skull and clavicle, hyaline cartilage, most abundant)

what are the steps to intramembranous ossification

1) ossification centers appear in the fibrous connective tissue membrane 2) bone matrix(osteoid) is secreted within the fibrous membrane and calcifies 3) woven bone and periosteum forms 4) lamellar bone replaces woven bone, just deep to the periosteum, red marrow appears

what is the 1st step to endochondral ossification

1) starts as cartilage model, perichondrium is invaded by blood vesssels to form periosteum, osteoblasts in periosteum form bone collar

what is the 2nd step to endochondral ossification

cartilage in the middle of the diaphysis hardens leaving a cavity

what is the 3rd step to endochondral ossification

periosteal bud invades cavity, trabeculae/spongy bone formed due to osteoblast activity, primary ossification center

what is the 4th step to endochondral ossification

diaphysis continues to grow, medullary cavity is formed, after birth- epiphysis becomes spongy bones when bud enter epiphysis, secondary ossification centers

what is the 5th step

epiphysis completes ossification, hyaline cartilage is only at surfaces of epiphysis and the epiphyseal plate

what are the two types of bone growth

interstitial(bones grows in length) and appositional bone growth(remodeling of bone, width/shape)

what is interstitial bone growth

bone will continue to grow in length as long as cartilage will equal bone conversion, at puberty osteoblasts increase, outgrows pace of hyaline cartilage and epiphyseal plate gets sealed

appositional bone growth

at periosteum: osteoblasts, at endosteum: osteoclasts

comminuted fracture

bone fragments into three or more pieces, particularly common in the aged whose bones are more brittle

compression fracture

bone is crushed, common in porous bones(osteoporotic bones) subjected to extreme trauma(as in a fall), only in vertebrae

sprial fracture

ragged break occurs when excessive twisting forces are applied to a bone, common sports fracture

epiphyseal fracture

epiphysis separates from the diaphysis along the epiphyseal plate, tends to occur where cartilage cells are dying and calcification of the matrix is occuring

depressed fracture

broken bone portion is pressed inward, typical skull fracture

greenstick fracture

bone breaks incompletely, much in the way a green twig breaks; only one side of the shaft breaks, the other side bends; common in children, whose bones have relatively more organic matrix and are more flexible than those of adults

what is osteoporosis

due to low bone mass, bones become porous and thinner, most vulnerable at vertebral column and neck of femur

who gets osteoporosis

women older than 65: gone through menopause, lack of estrogen(can’t absorb calcium efficiently), caucasian & asian; men can get it from poor diet; can also come from lack of exercise, diets poor in calcium & protein, and inadequate levels of vitamin D

how is osteoporosis detected

DEXA scan: low level radiation scan; shows composition of bone and % fat

how do you treat osteoporosis

osteoblast simulators, osteoclast inhibitors, IV(infusion), supplemental calcium & vitamin D, change in diet, estrogen replacement therapy, resistive exercise(stimulates bone growth, applies tension to bone, osteoblasts turn on), power plate

what is paget’s disease

chronic bone disease; excessive rates of bone deposition and bone reabsorption, immature bone; later stage bones become thick; not life threatening; bow-legged

what is rickets

form of osteomalacia but in children, bones not fully calcified so becomes soft, due to 1) low calcium phosphate 2) low amounts of vitamin D

examples of long bones

femur, metatarsals, etc.

short bones

cube-ish structures, tarsals, carpals

sesamoid bones

bones that grows inside a tendon; great toe, thumb, patella; creates power in motions, like a lever, important for gripping

flat bones

skull, scapula, and sternum

irregular/funky

vertebrae, pelvis

bone markings function

dictated by how bone touches each other/hole; muscle attaches to bone & creates stimulus

at which bone markings do muscles grow

tubercle, tuberosity, trochanter

spongy bone contains what

red bone marrow, flat/irregular bones

what is the periosteum

outer membrane of bone; 1st layer= dense irregular connective tissue, 2nd layer= osteogenic layer(osteoblasts/osteoclasts)

what does the medullary cavity contain

yellow bone marrow, lining of medullary cavity is endosteum

what do flat bones contain

spongy bone sandwich, red bone marrow; spongy bone has trabeculae which have red bone marrow

what is within the central canal/haversion canal

vein, artery, nerves

what are joints/articular

the place of contact between bones, between bone and muscles, and bones and teeth

what is the function of joints

provides both stability and mobility; most joints are a compromise between these two requirements, joints are the weakest points on the skeleton but are used to resist movements that would drive them out of alignment

how can joints be classified

by function or structure

how to we classify bones by structure

1) diarthrosis/diarthrotic: free moving 2)amphiarthrosis/amphiarthrotic: slightly movable 3) synarthrosis/synarthrotic: immovable

how to we classify joints by structure

based on the materials that binds bones together and the presence or absence of a joint cavity; structural classifications include fibrous, cartilaginous, and synovial

what is a fibrous joint

bones are connected by fibrous connective tissue; do not have a joint cavity, no space/cavity; most are immovable/slightly movable; the types are sutures, syndesmoses, and gomphoses

what are the types of fibrous joints

1) suture (short fibers): immobile(synarthrosis)

2) syndesmosis (longer fibers): slighty mobile (amphiarthrosis) and immobile

3) gomphosis (periodontal ligament): immobile

what is a cartilaginous joint

bones are united by cartilage; lack a joint cavity; immovable or slightly movable; two types= synchondroses, symphyses

what are the types of cartilaginous joints

1) synchondrosis (hyaline cartilage): immobile

2) symphysis(fibrocartilage): slightly movable

what are synovial joints

most movable type of joint(diarthroses); each contains a fluid-filled joint cavity; articular cartilage covers both ends; has a joint cavity: fibrous outside layer, synovial inside layer; some have articular disc(TMJ, knee)

what are the types of synovial joints

1) plane

2) hinge

3) pivot

4) condylar

5) saddle

6) ball-and-socket

all are freely movable, movements depend on design of joint

what are sutures

bones are tighly bound by a minimal amount of fibrous tissue, occur only between the bones of the skull, allow bone growth so the skull can expand with brain during childhood, fibrous tissue ossifies in the middle age- synotoses= closed sutures

what are syndesmoses

bones are connected exclusively by ligaments; amount of movement depends on length of fibers: tibiofibular joint- immovable synarthrosis, interosseous membrane- between radius and ulna(keeps bone in place, diarthrosis); short ligaments connected to bones; more stability(less mobility)

what are gomphoses

tooth in a socket; connected ligament= periodontal ligament; connections between gum and teeth

what are synchondroses

hyaline cartilage unites bones; epiphyseal plates; joint between first rib and manubrium

what are symphyses

fibrocartilage unites bones; resists tension and compression; slightly movable joints that provide strength with flexibility; intervertebral discs, pubic symphysis

are bursae and tendon sheaths synovial joints

no