musculoskeletal system

what is the main tissue in bones?

connective tissue

what are other tissues found in bones?

nervous tissue, blood connective tissue, and articular cartilage

what are the functions of bones

support, movement, protection, mineral storage, blood cell formation, energy metabolism

how many main types of cells are there?

3: osteoprogenitor cells, osteoblasts, and osteocytes

osteoprogenitor cells

stem cells that differentiate into osteoblasts

osteoblasts

actively produce and secrete bone matrix

osteoid

bone matrix

osteoclast function

reabsorb bone

osteoclast location

in the bone matrix

what do osteoclast produce?

secrete hydrochloric acid and lysosomal enzymes

long bones

longer than they are wide

examples of long bones

humerus, femur

short bones

roughly cube shaped

examples of short bones

carpals, tarsals

flat bones

thin, flat, often curved

examples of flat bones

sternum, scapula, ribs

irregular bones

various shapes that don’t fit into other categories

examples of irregular bones

facial bones, hyoid, vertebrae

compact bone

dense outer layer of bone

another name for spongy bone

cancellous or trabecular

spongy bone structure

trabeculae → little “beams” of bone with open spaces filled with marrow

what is reflected in the shape and anatomy of bones?

stress, tension, and compression on the bone

epiphysis

end of long bone

diaphysis

middle/shaft of long bone

endosteum

inner covering of the medullary cavity

yellow bone marrow

fills the medullary cavity

articular cartilage

covers epiphyses to protect from wear and tear from joints

periosteum

outer covering of the bone

red bone marrow

fills the spaces within the spongy bone

tuberosity

large rounded projection, may be roughened

crest

narrow ridge of bone, usually prominent

trochanter

very large, blunt, irregularly shaped process (only in the femur)

line

narrow ridge of bone; less prominent than a crest

tubercle

small rounded projection or process

epicondyle

raised area on or above a condyle

spine

sharp, slender, often pointed projection

process

any bony prominence

what surfaces form joints?

head, facet, and condyle

what are sites of muscle and ligament attachments?

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

head (bone marking)

bony expansion carried on a narrow neck

facet

smooth, nearly flat articular surface

condyle

rounded articular projection, often articulates with a corresponding fossa

what are depressions and openings for vessels and nerves?

foramen, groove, fissure, and notch

what are other depressions and openings?

fossa, meatus, and sinus

foramen

round or oval opening through a bone

groove

furrow

fissure

narrow slitlike opening

notch

indentation at the edge of a structure

fossa

shallow basin like depression, often serving as an articular surface

meatus

canal-like passage way

sinus

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

how do blood vessels, lymph vessels, and nerves travel through compact bone?

passageways

what is an osteon?

circular layers of a compact bone surrounding central canals (passageways)

what is another name for an osteon?

Haversian system

lamellae

very thin layer of bone

are there osteons in spongy bone?

no

lacunae

spaces between layers of lamellae

where are osteocyte found?

in lacunae

ossification

bone tissue formation

what is another name for ossification?

osteogenesis

what are bones modeled in?

hyaline cartilage

step one of ossification

bone collar forms around the diaphysis of the hyaline cartilage model

step two of ossification

cartilage in the center of the diaphysis calcifies and develops cavities

step three of ossification

the periosteal bud invades the internal cavities and spongy bone forms

step four of ossification

the diaphysis elongates and a medullary cavity forms

when does the secondary ossification center form?

fourth step

what do ossification centers do?

provide blood supply which allows for bone formation

step five of ossification

the epiphyses ossify

where does hyaline cartilage remain?

the epiphyseal plate and the articular cartilage

what does the epiphyseal plate do?

pushes the epiphysis away from the diaphysis which lengthens the entire bone

calcification

more calcium is present causing older chondrocytes to break down and die

when does the epiphyseal plate close?

towards the end of adolescence

what is another name for the epiphyseal plate?

growth plate

how do osteoblasts contribute to bone development

add bone tissue to the external surface of the diaphysis

how do osteoclasts contribute to bone development

removes bone from the internal surface of the diaphysis

appositional growth

growth of a bone by addition of bone tissue to its surface

where is growth hormone produced?

pituitary gland

function of growth hormone

stimulates epiphyseal plate

function of thyroid hormone

metabolism; keeps proper proportions of skeleton

sex hormones

estrogen and testosterone

function of sex hormones

promote bone growth and induces closure of epiphyseal plates

when do sex hormones begin

adolescence

types of cartilage

hyaline, elastic, fibrocartilage

what is the most abundant cartilage?

hyaline cartilage

how are chondrocyte set up in hyaline cartilage?

appears spherical - found in a lacuna

elastic cartilage locations

epiglottis and external ear cartilage

elastic cartilage more or less resilient than hyaline?

more resilient and more flexible

fibrocartilage

resists strong compression and strong tension

fibrocartilage locations

pubic symphysis, menisci of the knee, and anulus fibrosus

hyaline cartilage locations

costal cartilage, cartilaginous joints (ex. shoulder and hip), nose