BIOL 251 Bones and Skeletal Tissue Exam 2 Study Guide

support

function of bones that involves their role in holding up the body and cradling organs

protection

function of bones that involves surrounding internal organs to shield them from injury

attachment point

function of bones that involves their connections to tendons

storage

function of bones that involves their ability to reserve fats and minerals

hematopoiesis

formation of red blood cells in red bone marrow

osteocalcin

hormone produced by bones that regulates insulin release, glucose homeostasis, and energy expenditure

hyaline cartilage

type of cartilage tissue that contains collagen fibers

elastic cartilage

type of cartilage tissue that contains elastic fibers

fibrocartilage

type of cartilage tissue that is compressible and has great tensile strength due to its rows of chondrocytes that alternate with thick collagen bands

appositional

type of cartilage growth where new cartilage is laid on top of old cartilage at its surface, and cells just under the perichondrium lay down new matrix

interstitial

type of cartilage growth where cells divide and secrete matrix deep within old cartilage

axial skeleton

section of the skeleton encompassing the long axis of the body

appendicular skeleton

section of the skeleton encompassing the limbs and girdles

long bones

bones that are longer than they are wide

short bones

cube-shaped bones

sesamoid bones

bones that form in a tendon

flat bones

bones that are thin, flat, and curved

irregular bones

bones that do not fit into the long, short, sesamoid, or flat categories

lamellar bone

smooth and solid outer layer of bones

trabecular bone

spongy inner layer of bones containing red or yellow bone marrow

trabeculae

needle-like pieces of bone found within the trabecular layer of bones and in greatest concentration around lines of stress

diaphysis

the shaft of a long bone; vascularized by the nutrient vein and artery

medullary cavity

the space inside of the diaphysis containing bone marrow

epiphysis

the end of a long bone covered with articular cartilage and where the bone articulates with another bone or attaches to ligaments/tendons

periosteum

vascularized and innervated external covering of long bone surfaces except at the epiphysis

endosteum

covering of internal bone surfaces such as trabeculae and cavities, containing osteoprogenitor cells

osteon

stress-withstanding structural unit of compact bone

lamella

layers that pack closely together to form osteons

central canal

spaces running through the centers of osteons containing nerves and blood vessels

perforating canal

spaces extending from central canals connecting neighboring osteons and the medullary cavity

interstitial lamellae

incomplete lamellae found between complete osteons that fill inter-osteon gaps

circumferential lamellae

lamellae just deep to periosteum that circle completely around the diaphysis and resist long bone twisting

red bone marrow

tissue found inside of many bones that produces blood cells`

yellow bone marrow

tissue found inside the medullary cavities of long bones that serves as fat storage and can convert back to red marrow if necessary

osteoprogenitor cells

stem cells that are mitotically active and can either remain in this form or differentiate into osteoblasts

osteoblasts

cells that form bones by secreting unmineralized matrix until they are surrounded

osteocytes

mature bone cells that monitor and maintain the matrix, responding to mechanical stress and chemical signals

osteoclasts

bone-degrading cells that maintain, repair, and remodel bones, extract calcium from bones when it is necessary to maintain blood calcium homeostasis, and produce collagenase

calcium phosphate

the main mineral salt contributing to bone structure

osteomalacia

homeostatic imbalance of the bone where few calcium salts are deposited onto the bone, leading to weak bones in adults; caused by calcium or vitamin D deficiency

rickets

homeostatic imbalance of the bone where few calcium salts are deposited onto the bone, leading to weak bones in children; caused by calcium deficiency, vitamin D deficiency, or genetics

endochondral ossification

formation of ossified bone by cartilage replacement, occurring in most bones inferior to the skull; hyaline cartilage used as a blueprint for formation

bone collar

the first area of bone formed by bone matrix laid on cartilage surfaces during endochondral ossification

primary ossification center

the rigid and tough area of bone formed in the diaphysis after the formation of the bone collar; cartilage inside breaks down to form a cavity

periosteal bud

bud that invades the cavity during endochondral ossification containing nutrient vessels, nerve fibers, red marrow elements, osteoprogenitors, and osteoclasts

secondary ossification center

the rigid and tough area of bone that forms in epiphyses of bones during the later stages of endochondral ossification

epiphyseal plate

cartilage plate between the epiphysis and diaphysis of a bone that serves as the area of interstitial growth during bone lengthening; calcifies at the end of adolescence

growth hormone

hormone secreted by the anterior pituitary gland that controls epiphyseal plate activity

estrogen

sex hormone that causes a growth spurt at puberty, induces epiphyseal plate ossification in high levels, and feminizes the skeleton

testosterone

sex hormone that masculinizes the skeleton

deposition

the extraction of calcium from bone tissue to maintain homeostasis

parathyroid hormone

hormone that is released in response to low blood calcium levels and increases osteoclast number and activity in bone tissue

Wolff’s law

the concept that bones will remodel by increasing trabeculae concentration and compact bone thickness where the most mechanical stress is placed on it, as well as the opposite