Chapter 6 flashcards
What is the Axial Skeleton
- forms the longitudinal axis of the body
- consists of the bones of the skull, the vertebral column, and the thoracic cage
-protection, as they encase body cavities and protect the underlying organs
What is the Appendicular Skeleton
- consists of the bones of the upper and lower limbs and the pectoral and pelvic girdles
- motion and act primarily as levers and supportive structures to which muscles attach
Where do two bones meet/connect
at joints/ arrticulations
Depression markings
allow blood vessels and nerves to travel along a bone, or provide a place where two bones can articulate (form a joint)
Opening markings
enclose delicate structures and allow them to travel through bones
Projection markings
provide sites to which ligaments and tendons attach or where bones articulate
Facet
- depression marking
- shallow convex or concave surface where two bones articulate
- example: ribs
Fossa (Fossae)
- depression marking
- indentation in a bone in which another structure fits
- example: humerus
Fovea
- depression marking
- shallow pit
- example: femur
Groove (sulcus)
- depression marking
- long indentation along which a narrow structure travels
- example : rib
Canal (meatus)
- opening marking
- tunnel through a bone
- example: temporal bone
Fissure
- opening marking
- narrow slit in a bone or between adjacent parts of bone
- example: sphenoid bone, frontal bone
Foramen (formania)
- opening marking
- hole in a bone
- example: sphenoid, frontal bone
condyle
- projection marking
- rounded end of a bone that articulates with another bone
- example: mandible
crest
- projection marking
- ridge or projection
- example: ilium
head
- projection marking
- round projection from a bones epiphysis
- example: humerus head
tubercule and tuberosity
- projection marking
- small rounded bony projection, tuberosity is a large tubercule
- example: humerus (deltoid tuberosity)
epicondyle
- projection marking
- small projection usually proximal to a condyle
- example: humerus( medial epicondyle)
process
- projection marking
- prominent bony projection
- example; scapula (caracoid process)
spine
- projection marking
- sharp process
- example: scapular spine
protuberlance
- projection marking
- outgrowth from a bone
- example: occipital bone
trochanter
- projection marking
- large projection found ONLY on the femur
line
- projection marking
- long narrow ridge
long bones
- shape is LONGER than it is wide
- examples; humerus, hand and feet bones, fingers and toes
- shape rather than size
short bones (sandwich model)
- as LONG as they are WIDE
- examples: carpals, tarsals
- named for shape rather than size
- no diaphysis/epiphysis/medullary cavity, epiphyseal lines or plates
- instead, periosteum attached by perforating fibers and well supplied with blood vessels and nerves.
- outer layer of compact bone that surrounds the inner spongy bone.
flat bones (sandwich model)
- thin, broad, flat
- examples; most bones in the skull, ribs, sternum, pelvic bones
- no diaphysis/epiphysis/medullary cavity, epiphyseal lines or plates
- instead, periosteum attached by perforating fibers and well supplied with blood vessels and nerves.
- outer layer of compact bone that surrounds the inner spongy bone (diploe)
irregular bones (sandwich model)
- irregular shape
- examples: vertebrae and some skull bones
- no diaphysis/epiphysis/medullary cavity, epiphyseal lines or plates
- instead, periosteum attached by perforating fibers and well supplied with blood vessels and nerves.
- outer layer of compact bone that surrounds the inner spongy bone.
sesamoid bones (sandwich model)
- small, relatively flat, and oval-shaped bones located within tendons , give tendons mechanical advantage, provide muscle leverage, reduce wear and tear
- no diaphysis/epiphysis/medullary cavity, epiphyseal lines or plates
- examples: patella
- instead, periosteum attached by perforating fibers and well supplied with blood vessels and nerves.
- outer layer of compact bone that surrounds the inner spongy bone.
(long bone) periosteum
- composed of dense irregular collagenous connective tissue that is richly supplied with blood vessels and nerves
- periosteum is firmly attached to the underlying bone by collagen fibers
(long bone) perforating fibers
- collagen fibers
- penetrate deeply into the bone matrix, securing the periosteum in place
(long bone) diaphysis
- shaft
- very thick layer of compact bone
(long bone) epiphysis
- ends of long bones
- outer parts of the epiphyses are compact bone
- interior of the epiphyses consists of abundant spongy bone
(long bone) articular cartilage
- hyaline cartilage
- allows bones to rub together with reduced friction at joints
(long bone) medullary cavity
- large hollow interior portion of long bone diaphysis
- marrow is housed here (red and yellow)
- scant inner spongy bone
( long bones) compact bone
- hard dense outer bone
- composed of repeating OSTEONS
- resist the majority of stresses placed on it
( long bones) spongy bone
- inner honeycomb-like
- composed of TRABECULAE
( long bones) endosteum
- connective tissues membrane lining internal surfaces of bone
- thinner and lacks the fibrous outer layer that we see with the periosteum
( long bones ) epiphisiyal lines
- presence of lines running across the proximal and distal ends of the bone between the epiphysis and the diaphysis
(long bones) epiphiyseal plate; growth plate
- line of hyaline cartilage from which a long bone grows in length in children and adolescents
osseous tissue
bone tissue
bone matrix (ECM)
- inorganic 65% total bone weight (minerals)
- organic 35% total bone weight (collagen)
inorganic matrix
- calcium salts
- phosphorus
- gives bone its strength and the ability to resist compression, which allows it to perform its functions of support and protection
organic matrix
- osteoid
- consists of protein fibers, proteoglycans, glycosaminoglycans, glycoproteins, and bone-specific proteins such as osteocalcin
- collagen fibers
- form cross-links with one another and help bone to resist torsion (twisting) and tensile (pulling or stretching) forces
osteoblasts
- build bone and mature
- derived from osteogenic cells
- perform BONE DEPOSITION
ostecytes
- mature from osteoblasts
- help to maintain bone
- secrete chemicals maintaining ECM
osteoclasts
- break down bone
- derived from diffusion of bone cells formed in marrow
- BONE RESORPTION
(compact bone) lamellae
- rings containing osteons
(compact bone) central canal
- contains blood vessels and nerves that supply the cells of the osteon
- lined by endosteum
(compact bone) lacunae
- small cavities that are filled with extracellular fluid and located between lamellae
(compact bone) canaliculi
- Lacunae are connected to one another by tiny canals
- allow oxygen and nutrients from the blood to reach every osteocyte
(compact bone) interstital lamallae
- fill in spaces between osteons
(compact bone) circumferential lamallae
- outer and inner rings of lamellae are present just deep to the periosteum and superficial to the spongy bone
(compact bone) perforating canal
- The central canals of neighboring osteons are connected by a second type of canal
- run perpendicular to the osteons
- They carry blood vessels from the periosteum that merge with vessels in the central canals
( spongy bone) trabeculae
- forms a protective framework for the bone marrow
- performed by branching “ribs” of bone
- covered with endosteum and usually do not contain osteons
- they do contain concentric lamellae, within which we find canaliculi and lacunae housing osteocytes
- No central or perforating canals are present within trabeculae, and the cells obtain their oxygen and nutrients from the blood vessels in the bone marrow.
ossification (osteogenesis)
- process of bone formation
intramembranous ossification
- built on starting material known as a model that is made of a membrane of embryonic CONNECTIVE TISSUE
- flat bones
endochondral ossification
- built on a model made of HYALINE CARTILAGE
primary bone
- irregularly arranged collagen bundles, abundant osteocytes, and little inorganic matrix
secondary bone
- fully formed lamellae with regularly arranged collagen bundles that are parallel to one another, which makes it much stronger than primary bone
- higher percentage of inorganic matrix, which contributes to its strength
intramembranous ossification order
- Osteoblasts develop in the primary ossification center from mesenchymal cells
- Osteoblasts secrete organic matrix, which calcifies, and trapped osteoblasts become osteocytes
- Osteoblasts lay down trabeculae of early spongy bone, and some of the surrounding mesenchyme differentiates into the periosteum
- Osteoblasts in the periosteum lay down early compact bone
endochondral ossification order
- The chondroblasts in the perichondrium differentiate into osteoblasts
- The bone begins to ossify from the outside
2a. Osteoblasts build the bone collar on the external surface of bone
2b. Simultaneously, the internal cartilage begins to calcify and the chondrocytes die - In the primary ossification center, osteoblasts replace the calcified cartilage with early spongy bone; the secondary ossification centers and medullary cavity develop.
- As the medullary cavity enlarges, the remaining cartilage is replaced by bone; the epiphyses finish ossifying
longitudeal growth order
- Chondrocytes divide in the zone of proliferation
- Chondrocytes that reach the next zone enlarge and mature.
- Chondrocytes die and their matrix calcifies
- Calcified cartilage is replaced with bone
bone remodling
bone deposition and bone resorption
bone deposition
-carried out by OSTEOBLASTS in the periosteum and endosteum
- make the components of the organic matrix, as well as facilitate the formation of inorganic matrix
- proteoglycans and glycoproteins that bind to calcium ions, and it appears that they also secrete vesicles containing calcium ions, ATP, and enzymes
- bind to collagen fibers, and their calcium ions eventually crystallize, which ruptures the vesicle and begins the overall process of calcification
bone resorption
- carried out by OSTEOCLASTS
- osteoclasts secrete hydrogen ions (H+) from their ruffled borders onto the bone ECM
- breaks down the pH-sensitive hydroxyapatite crystals in the inorganic matrix
- REUSE
calcitonin in bone remodeling
- blocks osteoclasts
parathyroid hormone in bone remodeling
- stimulation
- balance
calcitriol in bone remodeling
- reduce PTH secretion
- increase calcium
- promotes osetoblasts
osteogenic cells
creation of stem cells , divide by mitosis, turn into blasts
primary ossification center
primary bone laid down, turns secondary
secondary ossification center
located in epiphysis of long bones, where ossification starts later in development process
growth hormone
pituitary, regulate growth til puberty
gigantism
overproduction of growth hormone before puberty
acromegaly
increase in growth hormone after plate is closed resulting in bone thickening
simple fracture
stays in skin
compound fracture
penetrates through skin
spiral fracture
twisting forces
compression fracture
crushed
comminuted fracture
shattered in multiple pieces
avulsion fracture
tendon/ligament pulls off
greenstick fracture
kids
epiphyseal plate fracture
includes plate
