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?