Bones and Skeletal Tissue Flashcards
how many bones are in the human body?
206
sutural bones
extra skull bones
sesamoid bones
bones that develop from tendons
What does the skeletal system consist of?
bones, cartilage, ligaments, other connective tissue
functions of the skeletal system
-support
-protection
-body movement
-hemopoiesis
-mineral storage
characteristics of cartilage
-lots of matrix, has many sugar molecules
-avascular
-non-innervated
-chondrocytes and lacunae: cells and spaces holding them
function of cartilage
-support
-withstand deformation
perichondrium
-layer covering cartilage with external (dense irregular connective tissue) and internal layers
-resists outward pressure and growth/repair of cartilage
hyaline cartilage
-most abundant, supports soft tissue, weakest,
-fetal skeleton, articular cartilage, nose, trachea, ribs-sternum
fibrocartilage (what and where)
-dense collagen fibers,
-found in intervertebral discs, pubic symphysis, meniscus
elastic perichondrium
has a lot of elastic fibers in matrix, flexible
-found in ear
characteristics of bone
-more solid than cartilage due to calcium phosphate in matrix
-1/3 organic components, inorganic
-2 types: spongy and compact
osteoblasts
-derived from mesenchyme
-secrete collagen and matrix (osteoid)
-secretes regulatory hormones for sugar metabolism
osteoclasts
-modified monocytes
-large
-multinuclear
-bone reabsorbing
-release lysosomal enzymes
-secrete acid to dissolve minerals
osteocyte
-mature cells formed when matrix surrounds osteoblasts
-trapped in lacunae
long bones
-more common
-levers
-upper/lower extremities
short bones
-long as wide
-articulate and distribute forces
-ex: carpals, tarsals, sesamoid bones
flat bones
-increases surface for muscle attachment
-hemopoiesis in adults
-ex: skull, ribs, scapula
irregular bones
-complex shapes
-ex: vertebrate, coxae, some in skull
red bone marrow (function and location)
-produces RBC
-found in spongy bone and medullar cavity
yellow bone marrow
red bone marrow turned into fatty tissue
ossification(when)
begins in 4th week of prenatal development
endochondral ossification
-develops from hyaline cartilage
-most skeleton develops this way
intramembranous ossification
-develops from mesenchyme
-found in some skull bones, clavicles, sesamoid
diametric growth
occurs at periosteum of diaphysis
vertical growth
epiphyseal plate, genetically determined
function and location of spongy bone
-distributes stress, reduces weight
-found in epiphysis in long bones, diploe in flat bones, trabeculae
