anatomy exam 2: bones and skeletal tissues

spongey (trabecular) bone tissue

looks like a sponge under a microscope, fills inside of bones, vessels snake around the outside of the tissue

fibrocartilage

many layers of highly condensed collagen fibers; rows of round chondrocytes among parallel rows of collagen fibers; SHOCK ABSORPTION; found in menisci of knee, cartilaginous discs between vertebrae, pubic symphysis, vertebral discs

Haversian canal

one of a network of tubes running through compact bone that contains blood vessels and nerves

bone deposition

osteoblasts require essential ions to deposit more bone, they deposit more bone when the bone is subjected to added demand or when the bone is injured, the bone is made stronger and more resistant to cracks or breaks by mineral salt ions which are tightly packed together on the outside of the bone; essential ions (ie calcium) must be present for osteoblasts to lay down bone tissue

bone resorption

osteoclasts break down bone by secreting lysosomal enzymes and hydrochloric acid onto the bone, degrading the organic matrix. this allows mineral salts to leach out and dissolve, releasing ions (calcium) into the interstitial fluid and eventually the blood. the dead osteocytes and collagen fibers are phagocytosed out

deep layer of periosteum

osteogenic; two types of cells: osteoblasts and osteoclasts

sharpey's fibers

perforated collage fibers that wedge themselves into bone tissue and attach the periosteum to the bone; found in greatest abundance on parts of the bone where muscles attach; tuber-sixties on a bone here formed due to muscles pulling on the periosteum

ossification (osteogenesis)

process by which bone forms

red bone marrow

produces blood cells; found in epiphyses and spongy bone tissue

hemopoiesis

production of red blood cells, red bone marrow

metaphysis

region where the diaphysis and epiphysis meet; location of the epiphyseal plate and line

epiphyseal line

remnant of growth plate; calcified remnant of the plate

short bones

roughly cuboidal in shape, include the ankle and wrist bones

canaliculi

small transverse canals through which the point branches of the osteocytes can "communicate" with one another through gap junctions; this way osteocytes are able to engage in metabolic coupling so the osteocytes that are not in contact with the blood can receive the nutrients that they need

osteogenic cells

stem cells that differentiate into osteoblasts

circumferential lamellae

lamellae of compact bone that have a parallel arrangement near the surface of compact bone; form a "circumference" around all of the osteons making the outside of the bone is smooth, continuous, and doesn't "twist"

perichondrium

layer of dense connective tissue surrounding cartilage like a girdle, adds strength ti oppose any "squishing"or deformation of the tissue

diaphysis

long shaft of the bone between the two epiphyses; wall is made of compact bone tissue

long bones

longer than they are wide, two distinct ends; humerus, ulna, femur, tibia, phalanges, clavicle, fibula

osteoporosis

A condition in which the body's bones become weak and break easily; outside of the bone is porous

periosteum

A dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles; covers the external bone surface and gives the bone a whitish outer covering

osteoclasts

Bone-destroying cells; demineralize or dissolve bone disuse, multi nucleated and have a "ruffled" border that increases the surface area of a cell

Haversian system

Central canals surrounded by osteons; contain the blood vessels and nerves that serve the bone

lamellae

Concentric rings made up of groups of hollow tubes of bone matrix

hyaline cartilage

Most common type of cartilage; firm, strong and relatively flexible; found in locations that need harness for protection but also flexibility for movement; ends of long bones, growth plates within bones, respiratory structures (tracheal rings), costal cartilages, embryonic skeleton

osteons

Structures in bones that carry the blood supply

perforating canals

allow the transfer of blood between the central canals of different osteons; connect the osteons to one another, and they connect osteons to the periosteum

peri

around

osteoblasts

bone forming cells, deposits bone tissue, immature bone cells that do not divide

bone remodeling

bone is continuously deposited and removed, mostly at the endosteal surface, spongy bone is replaced more quickly than compact bone

nutrient foramen

bones are extremely vascularized, one or two large arteries "dive into" the shaft of the bone through holes called the ____________, once the artery in in the bone it runs up the central canals of the osteons and supplies blood within the tissue itself

bone resorption

bones release stored calcium into the blood

calcium and phosphorus

bones store/release minerals such as

irregular bones

bones that have an unusual or complex shape and that provide both support and protection yet allow flexible movement; individual vertebrae in spinal column, ox coxae, bones in face

too much bone resorption

brittle bones that are easily fractured

connective tissue with small number of cells and abundant extracellular matrix

cartilage

chondrocytes

cartilage cells

elastic cartilage

cartilage with abundant elastic fibers; more flexible than hyaline cartilage; only found in two locations in the outer ear and epiglottis

epiphyseal plate

cartilaginous area at the ends of long bones where lengthwise growth takes place in the immature skeleton

lacune

chondrocytes almost always are found inside small spaces called

osseous tissue

connective tissue in which the matrix is hardened by the deposition of calcium phosphate and other minerals; bone tissue; highly vascularized

osteogenic

creates new bone cells

superficial layer of periosteum

dense irregular connective tissue which allows for strength in multiple directions

mesenchyme

embryonic connective tissue, origin of all connective tissue

interstitial lamellae

fill in the gaps between the circular osteons using remains of old osteons. without these, the bones would become brittle

intramembranous ossification

formation of bone from within mesenchyme, mesenchymal cells differentiate into osteocytes blasts, which secrete osteoid; the calcified osteoid is laid done in a network of blood vessels called woven bone; lamellar bone then replaces the woven bone to form bone plates and red blood marrow appears; only a small number of bones are developed this way (cranial bones, facial cones and clavicle)

endochondral ossification

formation of bone within hyaline cartilage, hyaline cartilage is turned into osseous tissue

growth of new bone

formed in the embryo, until a person reaches adulthood, remodeled throughout one's life, bone is fractured and must be repaired

osteocytes

formerly known as osteoblasts, became trapped in matrix and matured

fibers

gel like extracellular matrix of elastic and fibrocartilage

fibrils

gel like extracellular matrix of hyaline cartilage

appositional growth

growth in width of bone; osteoblasts deposit bone tissue to circumferential lamellae; osteoclasts destory bone tissue on the inner diaphyseal wall; the diameters of the bone and the medullary cavity increase

how bones get longer

hyaline cartilage grows on the epiphysis side of the epiphyseal plate; the cartilage is replaced by bone on the dialysis side of the epiphyseal plate

articular cartilage

hyaline cartilage that can be found at the end of articulating bones; smooth white tissue that covers the end of bones in joints

endo

in or within

bone remodeling occurs

in response to mechanical stress on the bone and to maintain homeostasis of calcium and phosphate levels in body fluids

medullary

innermost portion of something

sesamoid bones

subclass of short bones; round bones found near joints (e.g., the patella); get their name because they look like sesame seeds

functions of bones

support, protection, movement, mineral storage, hemopoiesis (new red blood cells), metabolism, energy storage

trabeculae

supporting bundles of bony fibers in cancellous (spongy) bone, form pores, covered in endosteum which provides the tissues with nutrients

medullary cavity

the cavity within the shaft of the long bones filled with bone marrow; yellow bone marrow has a yellowish/orangeish hue because it has a carotene pigment

compact bone tissue

the strongest form of bone tissue that makes up the bulk of the diaphysis of a long bone; consists of many individual units called osteons, which consist of a central canal surrounded by several concentric rings called lamellae; blood vessels run through the osteons

endosteum

the thin membrane that lines the internal surface of the bone; lines the trabeculae of spongy bone in the medullary cavity as well as the central canals of osteons; OSTEOGENIC; highly vascularized

flat bones

thin, flattened, and usually curved, two thin layers of compact sandwiching spongey bone (skull, ribs, sternum, scapula) **ribs are flat bones because they only have one pronounced end

bones, joints, cartilages

three components of the skeletal system

epiphysis

two ends of the bone (proximal and distal)

yellow

what bone marrow plays a role in energy storage (its makeup is predominantly adipose tissue)

osteoblasts

what cell is involved in bone deposition? "the construction workers"

osteoclasts

what cell is involved in bone resorption?