1. Support: structural framework, attachment for tendons and ligaments
2. Portection: protects internal organs
3. Movement: assist in movement
4. Mineral homeostasis: keep blood calciem and phosphate within normal limits by storing and releasing these minerals.
5. Hematopoesis: prodution of blood cells in red bone marrow
6. Fat (energy) storage: triglycerides stored in yellow bone marrow
True or false: Bone is not a type of connective tissue.
false.
Osteogenic cells
a bone stem cell
the precursor to all the other cell types
What are osteoblasts?
they are dividing cells
they are responsible for laying down the components of bone
we can disstinguish them from other cells which all start with "osteo-" by remembering that they are bone building blasts.
What is the funciton of osteocytes?
they maintain bone integrity within spaces inside of bone
Osteoclasts
Bone-chewing
constsnly tunnel through bone, dissolving the bone matrix as they go.
They are followed by osteoblasts
in this way bone is constantly renewed and can sytrengthen when needed.
Both _________ and _________ play an important role in keeping blood ________ and phosphorus within normal limits so they are controlled by _________.
osteoblasts, osteoclasts, calcium, hormones
What are the four cell types found in bone?
osteogenic cell: precursor to other cell types
Osteoblast: forms bone (bone building osteoblasts)
osteocyte: maintains bone tissue
osteoclast: break down bone (bone chewing osteoclast)
osteoblasts and osteoclasts are regulated by hormones
What are the two components of bone?
inorganic and organic
Hydroxapatite
The ionorganic portion of bone
a compound of calcium, phosphate and hydroxyl groups
its chemicla formula is : Ca10(PO4)6(OH)2
This forms the rigid, brittle inorganic matrix of bone.
Bone also has an organic matrix, made up of mostly _______ ____ __.
collagen type I
Bone is natures _________ material. Just like the skin of amodern jet fightyer is composite material of metal and non-metal, ______ depends on the proper mixture of _______ and ________ components.
composite, inorganic, organic
True or False: If bones have to little mineral, it becomes brittle and fractures easily.
False. If bones have to much mineral, it becomes brittle and fractures easily.
- This happens in the disease osteogenesis imperfecta, or "brittle bone disease".
What causes children with rickets and adults with osteomalacia to have soft and pliable bones?
If the bones have to much collagen
Why is it nessesary to have both mineral (inorganic) and collagen (organic) components working together?
Mineral alone is to brittle
-Osteogenesis imperfecta
Organic alone is to flexible
-rickets or osteomalacia
What are the two main types of bone?
Compact bone
-gives bone its strength
Spongy bone
-bone marrow is found amongst cavites of spongy bone
(usualy in centers of a long bonelike the femur
Compact Bones
Hard dense tissue
give structural and support
made up of osteons- also called the Haversian systemsOsteons are cylanders of bone
- concentric lamelae of extracellular matrix
- cyllander runs along the length of bone
-blood and lymphic vessels run in the center of each cylinder
Each osteon consists of a series of concetric rings called ________. In the center of this structrue is a _____ (_____ ___ or ________ ______) that runs the length of the bone, carrying ______ and _______ vessels.
lamellae, canal, central canal, haversian canal
Lacunae
singular lacuna, Latin for "lake"
small spaces betweeen the lamellae
contain osteocytes
Canaliculi
singular canaliculus, Latin, "small canals"
small channels that join adjacent lacunae.
Perforating canals (Volkmann canals)
run radically in long bones to join adjacent central cannals
Spongy bone
found in and forms the marrow cavity of long bones- like the femur & humerus
-this is where fat is stored (yellow marrow)and where blood cells are born in a process called hematopoiesis (in red marrow)
spongy bone is made up of trabeculae
Osteocytes lie in open spaces called lacunae- Latin "lake"
-canaliculi ( "little canals") link the lacunae
Osteoclasts and osteoblasts lie along the suface of each trabeculae
Some bones (e.g. _____) are made up almost entirely of _____ ______ with just a thin shell of _____ bone on the outsitde.
skull, spongy bone, compact
True or False: The structuer of spongy bone is different from that of compact bone since it has a different function.
True.
In spongy bone, there are several ________-organized rings, not as regular as the lamellae of ________, but still with lacunae containing osteocytes and with _________ connedting to the lacunae
loosely, osteons, canaliculi
Sevral of the loosely organized layers, found in spongy bone, form spiky projections called
trabeculaeosteoclasts and osteoblasts are found around the outside of the trabeculae
What are the three types of Cartilage?
Hyaline catilage
Fibrocartilage
Elastic cartilage
True or False: The skeletal system is not all compact bone or spongy bone.
True
Much of the skeleton is made up of catilage
What are the functions of Cartilage?
Forming flexible skeletal structures
Joining bones at synathroses (nearly immovable joints between bones)
Lining joiont surfaces in synovial joints (freely moveable joints)
Forming scaffolding for new bone formation
Hyaline cartilage
Greek - "glassy"
resembles glass: shiny and translucent
has a great deal of ground substance with no apparent structure
the living cells (chondrocytes) that lay down cartilage are found in little spaces (lacunae) here and there amongst the glassy ground substance.
Most cartillage in the body is hyaline cartilage
-
lining joints and forming much of the nose and ribs
Fibrocartilage
More fibrous in appearance and structure
chandrocytes are found in lacunae
The ground substance has collagen fiobers running through it
Found in the disks between vertebrae, in the pubic symphysiswhere the two halves of eh pelvis are joined, and in the meniscus of joints.
Elastic cartilage
has elastin fibers in place of collagen fibers found in fibrocartilage
found in the ear and epiglottis- two structures that need to be flexible and snap back into shape when moved and relased
