11.8 skeletal system Flashcards
ecdysone
hormone involved in melting and metamorphosis
cartilage
avascular connective tissue; softer and more flexible; (ex: ear, nose, larynx,
trachea, joints)
- 3 types: hyaline, fibrocartilage, and elastic.
hyaline cartilage
(most common – reduced friction/absorbs shock in joints)
cartilage development
from mesenchyme tissue, differentiates to chondrocytes that then secrete
molecules that form cartillagenous matrix (collagen + proteoglycans).
how abundant is collagen
most
abundant protein in vertebrates
what is collagen surrounded by
dense fibrous connective tissue called
perichondrium. It is derived from the mesenchyme
mesenchyme
(the embryonic connective
tissue that gives rise to most connective tissue cells).
bone structure
(living) connective tissue; hard and strong, while elastic and lightweight
functions of bone
support, protection, assistance in body movement, mineral storage, blood cell production, and energy storage in form of adipose cells in marrow
mature bone
woven bone is replaced by lamellar bone. two types are spongy and compact
immature. bone
Woven bone is immature and
weak (first bone to form during development and in fracture repair).
Chondrocytes
in cartilage
fibroblasts
the most common type of cell found in connective
tissue, and are involved in synthesis of ECM. tendons/ligaments/skin
Axial skeleton
basic framework (skull, vertebral column, rib cage)
Appendicular skeleton
bones of appendages, pectoral and pelvic girdles(basically
everything that isn’t axial). Femur is longest bone.
Sutures
immovable joints (holds together bones of skull)
Ligaments
bone-to-bone connectors; strengthen joints
ACL ligament
connects femur to tibia and limits rotational knee
movement
Tendons
dense connective tissue that connects muscle-to-bone; bend
skeleton at moveable joints
joint at the shoulder is
ball and socket joint (movement in all planes),
knee joint is
hinge joint (movement in one plane only)
Origin
point of attachment of muscle to stationary bone
Insertion
– point of attachment of muscle to bone that moves
Extension
straightening of joint
Flexion
bending of joint
osteoarthiritis,
cartilage that covers the bone ends of freely movable joints begins to wear away
(due to aging).
Rheumatoid arthritis is
a degenerative disorder with a genetic basis.
-The foramen is
an opening that allows for the passage of nerves, e.g. the foramen magnum is the skull
cavity that allows passage of the spinal cord.
mandible.
strongest bone in face
TMJ
attaches the upper and lower jaw.
Fibrous joint
connect bones without allowing any movement (Ex: skull, pelvis, spinous process
and vertebrae)
cartilaginous joint
bones attached by cartilage, allow little movement (Ex: spine and ribs)
Synovial joint
allow for much more movement; most common; filled with synovial fluid which
acts as a lubricant (Ex: carpals, wrist, elbow)
Osteoprogenitor/Osteogenic: type of bone
differentiate into osteoblasts [part of the mesenchymal stem cell lineage]
Osteoblasts:
secrete collagen and organic compounds upon which bone is formed. Incapable of
mitosis. As they release matrix materials around themselves enveloped by matrix differentiate into osteocytes (remember, Blast means Build)
Osteocytes:
incapable of mitosis; exchange nutrients and waste material w/ blood
Osteoclasts:
resorb (destroy) bone matrix, releasing minerals back to blood. They have carbonic
anhydrase [recall the rxn it catalyzes]. Develop from WBC’s called monocytes [hematopoietic stem cell
lineage]
Compact bone- structure
- highly organized, dense bone that doesn’t appear to have cavities from outside.
- Constantly remodels: osteoclasts burrow tunnels (Haversian canals)
throughout. - Osteoclasts are followed by osteoblasts, which lay down new matrix onto tunnel walls forming concentric rings (lamellae). Osteocytes trapped between the lamella (in a space called the lacunae) exchange nutrients via small canals
(canaliculi). The Haversian canals contain nerves, blood vessels, and lymph vessels;
they are connected by Volkmann’s canals. The entire system of lamellae + Haversian
canals is called an osteon (Haversian system). Compact bone surrounds the
medullary cavity which is filled with yellow bone marrow that contains adipose cells
for fat storage.
YIKES read notes and look at diagrams for this
**
rank size of bone structure
osteon is big, then haversian xanal, then canaliculi/osteocyte
Spongy (Cancellous) bone-
less dense and consists of an interconnecting lattice of bony spicules (trabeculae); filled with red bone marrow (site of hemopoiesis - RBC development)
Long bone structure
typically has a long shaft (diaphysis), and two ends (each composed of a metaphysis and epiphysis). Sheet of cartilage between the metaphysis and epiphysis called epiphyseal plate. Bone growth occurs at cartilaginous epiphyseal plates that are replaced by bone in adulthood. Bone increases in length but also in diameter
along the diaphysis as well.
bone and calcium levels
In the blood calcium salts only slightly soluble, most is not free ions but bound to proteins or phosphates. Most of the Ca2+ in body is stored in bone matrix as hydroxyapatite (a calcium phosphate mineral) which alongside collagen fibers providing great tensile and compressive strength. Calcium
phosphate (CaHPO4) is the main calcium compound in bone. 99% of calcium in the
body is contained in bones and teeth!
hydroxyapatite mineral
If stress is put on a bone, osteoblasts deposit collagen and release calcium
phosphate to strengthen the bone – the mineral hydroxyapatite is produced.
Bone Formation Endochondral ossification- cartilage
during FETAL stage of development
bone (EX: long bones; limbs, fingers, toes)
Intramembranous ossification
undifferentiated connective tissue replaced by bone
▪ (EX: flat bones; skull, sternum, mandible, clavicles)
Haversian canal
contains bone nerves and blood supply
periosteum membrane,
bone is surrounded y it. has lots of blood vessels. tendons integrate with it
Osteoperosis
causes bone density to decrease, easier to break/fracture. Estrogen can help maintain bone density (but can increase female risk of blood clots, heart disease, and cancer). Prevention of osteoporosis: calcium, vitamin D, and exercise.
