Skeletal System - 1a Flashcards
- gives the vertebrate body shape
- provides support and movement via attachments for soft tissue and muscle
- protects vital organs
- major site for red marrow for production of blood cells
- plays a role in the metabolism of minerals (calcium and phosphorus)
- helps maintains homeostasis
mineralized tissues
Principal types of rigid skeleton
- exoskeleton
- endoskeleton
- formed from or within the integument
- bony skeleton derived from the dermis
- keratinized skeleton from the epidermis
exoskeleton
exoskeleton
- bony skeleton from dermis
- keratinized skeleton from epidermis
- forms deep within the body from mesoderm and other sources
- bony skeleton
- fibrous connective tissue
- cartilage
endoskeleton
endoskeleton
- bony skeleton
- fibrous connective tissue
- cartilage
Different types of skeleton based on the composition
- cranial skeleton or skull
- postcranial skeleton
cranial skeleton or skull
- splanchnocranium
- chondrocranium
- dermatocranium
postcranial skeleton
- axial skeleton
- appendicular skeleton
axial skeleton
- vertebral column
- notochord
appendicular skeleton
- limbs
- girdles
Composition of skeleton
- mineralized connective tissue
- ligaments
- tendons
- bursae
mineralized connective tissue
- bone
- dentin
- cartilage
- enamel
forms bone
osteoblast
forms dentin
odontoblast
forms cartilage
chondroblast
forms enamel
ameloblast
fibrous connective tissue that attaches bone to bone
ligament
fibrous connective tissues that attach muscles to bones and help enable movement
Tendons
small fluid-filled sacs that reduce friction between moving parts in your body’s joints
Bursae
- semirigid supportive axial rod of protochordates and all vertebrate larvae and embryos
- composed of large vacuolated cells surrounded by elastic and fibrous sheaths
- stiffening device
notochord
except in jawless vertebrates, what happens to notochord
surrounded or replaced by back bone during embryonic development
fate of notochord
- nucleous pulposus
- constricted in centrum
- inorganic components of bone comprise 60% of the dry weight (largely calcium hydroxy-appetite crystals) and provide the compressive strength of bone
- organic component is primarily collagen, which gives bone great tensile strength
bone
bones are largely composed of what
calcium hydroxy-appetite crystals
organic component of bone which gives bone great tenstile strength
collagen
influence crystal deposition
osteoblasts
cementing substance of bones
water + mucopolysaccharides
Skeleton based on density
- compact or osteon bone
- spongy or cancelous bone
- dentin
- accelular bone or aspidin
consist of layers of mineralized collagenous bundles arranged concentrically around a Haversian canal (arteriole, venule, lymph vessel and nerve fibers)
compact or osteon bone
what is in the Haversian canal
- arteriole
- venule
- lymph vessels
- nerve fibers
cylindrical unit of bone that is the functional unit of compact bone
osteon
- where osteoblasts can be found
- filled with interstitial fluid (calcium & phosphate ions constantly being deposited or withdrawn on the matrix)
lacunae
interconnects the lacunae and houses the protoplasmic processesextending from the osteocytes (bone cells)
Canaliculi
- open, interlacing framework of bony tissue with marrow cavities lined by an endosteum
- constitutes the core of most bone
spongy or cancelous bone
lines the spongy or cancelous bone
endosteum
forms rigid framework that provides maximum strength at areas of stress
trabeculae
arrangement of lamellae in spongy bone
irregular
- reticulum of connective tissue fibers that support blood vessels,
- nerve fibers, and adipose tissue (yellow marrow)
marrow
(red marrow) in some bones produces RBC and some WBC.
hemopoietic tissue
- thin connective tissue that lines the marrow cavity
- can deposit and remodel bones
endosteum
dense fibrous membrane that covers all bones except at their articular surfaces
periosteum
- odontoblasts not trapped in lacunae
- odontoblasts found at the inner border, leave behind protoplasmic processes in canaliculi
- outer layer of dermis, frequently coated by enamel or enameloid
- dermis of earliest vertebrates
dentin / dentine
extend all the way to the surface of the dentin
dentinal tubules
outer layer of the dermis, frequently coated by __ or __
- enamel
- enameloid
- osteoblasts retreat as they deposit bone and leave behind no processes or canaliculi
- fibrous plates of the flexible scales of modern fishes and cementum of vertebrate teeth
accelular bone or aspidin
Different types of ossification
- endochondral or replacement bone
- intramembranous bone
bones that develop from cartilage
endochondral or replacement bone
- develops directly from sheets of embryonic cells
- face, cranium, clavicle
intramembranous bone
Stages of intramembranous ossification
- an ossification center appears in the fibrous connective tissue membrane
- bone matrix (osteoid) is secreted within the fibrous membrane
- woven bone and periosteum form
- bone collar of compact bone froms and red marrow appears
- within a matrix of collagenous connective tissue
- cells lie in lacunae
- intercellular matrix contains a sulfated mucopolysaccharide
cartilage
where do the cartilaginous cells lie
lacunae
what does the intercellular matrix of cartilage contain
sulfated mucopolysaccharide
how do chondrocytes get oxygen and nutrient
by diffusion
what does cartilage resist
compression
Types of cartilage
- hyaline cartilage
- fibrocartilage
- elastic cartilage
- least differentiated
- precursor of replacement bone
- articular surfaces of the bones within the joints of tetrapods
hyaline cartilage
- cartilage with exceptionally thick, dense collagenous bundles
- intervertebral disc of mammals
fibrocartilage
- collagenous fibers plus network of elastic fibers
- pinna of the ear, walls of the outer ear canals; epiglottis
elastic cartilage
have purely cartilaginous skeletons
- jawless vertebrates
- elasmobranchs
- when calcium salts are deposited within the intertitial substance of hyaline cartilage or fibrocartilage
- jaws of shark
calcified cartilage
what is deposited in calcified cartilage
calcium salts
- process of bone resorption and replacement
- to accommodate brain growth; in response to mechanical stress
skeletal remodeling
- tendons and ligaments that are flat and wide
- mammalian scalp (gala/galea aponeurotica)
aponeurosis
site where two bones or carilage meet
arthrosis or joint
Different kinds of arthrosis or joints
- diarthrosis
- amphiarthrosis
- synarthrosis
- freely movable in one or more planes and the articular surfaces are covered with hyaline cartilage
- joint is enclosed in a fibrous capsule lines bysinovial membrane that secretes a lubricatory fluid - e.g. knee and elbow jointsin mammals
diarthrosis
- fibrocartilage unites the components of the joint and fibrous joint capsules keep the bones properly aligned
- no synovial membrane
- permits limited movement
- joint between the centra of mammalian vertebrae
amphiarthrosis
sutured joint
synarthrosis
- irregular jagged seam at the junction of two bones that renders the joint immovable
- roof of the skull
suture
- condition wherein the sture between two bones become obliterated during development
- e.g. skull of birds
ankylosis
- joint in the midline of the body in which bilateral bones are separated by a pad of fibrocartilage
- movement is severely restricted
symphysis
develop by endochondral or intramembranous ossification in areas subject to continual stress in amniotes
Heterotopic bones
e.g. of Heterotopic bones
- os cordis
- baculum (os penis)
- os clitoris
in the interventricular septum of the heart of deer or bovines
os cordis
septum between the spongy bones of the penis of dogs, basal primates
baculum / os penis
septum in female mammals
os clitoris
- mineralized nodules in tendons and ligaments
- patella or knee cap
sesamoid tendon or bone
