Bones
True or False: Lamellae are in osteons
True
True or false: the primary site for intermembraneous ossification is the skull
True
True or False: If you break a bone, it will bleed
True! Bones are highly vascularized. (depends on the break)
True or False: bone remodeling needs osteoclasts
True. Osteoclasts break down old bone tissue to allow for the new shaping of the bone.
What are the functions of bones?
1. Structural support 2. storage of minerals 3. protection of organs 4. production of blood cells 5. mechanical basis for movement
What are the two types of bone ossification?
1. intramembraneous (mesenchymal - direct) 2. inter-cartilagenous (endochondral - indirect)
How do bones get bigger due to mechanical stress (running, weight-lifting)
1. spongy bone forms along lines of compression 2. bony landmarks form at attachment points of large muscles that are pulling
True or False: the endosteum contains osteocytes
False
True or False: In inter-cartilagenous ossification, the bone directly replaces the cartilage
False. The cartilage is disintegrates, and bone cells move into the spaces left behind
what is the central canal of an osteon called?
Haversian canal
What is being replaced at the secondary ossification center of a long bone?
Hyaline cartilage,at the metaphysis
What happens to the blood vessel during appositional bone growth?
It becomes encircled by lamellae, and becomes the Haversian canal at the center of a new osteon
What process is unbalanced in osteoporosis?
Osteoclasts are more active than osteoblasts / osteocytes
what bone disease leads to weak and soft bones due to inadequate calcification?
Osteomalacia (rickets in children)
what bone disease leads to spongy bones (which also makes them soft and weak)?
Paget's disease
What is the primary ossification center of a long bone?
The dyaphysis
What is appositional bone growth?
The growth of bone around an external blood vessel
What is the key feature of Marfan's disease?
abnormal connective tissue structures
What is an immature bone cell called?
an osteoblast
What kind of bone cell breaks down bone?
an osteoclast
What is a mature bone cell called?
an osteocyte
What is the basic functional 'unit' of bone?
an osteon
What is the first cell in the bone cell progression?
an osteoprogenitor
What is a Haversian system?
another name for osteon -- the basic functional 'unit' of bone
What is between the trabeculae in spongy bone?
bone marrow
what bone diseases lead to abnormally short people?
dwarfism ( all bones don't grow) achrodroplasia (abnormal activity at epiphyseal plates)
What is the tissue covering an osteon called?
endosteum
What is another name for the metaphysis?
epiphysial plate
Where is most red bone marrow found?
flat bones, proximal epiphyses of large long bones, irregular bones (vertebral bodies, pelvic bones)
What kind of cartilege is usually found at bone articulating surfaces?
hyaline
What is the metaphysis made of?
hyaline collagen
What is the center of a long bone called?
medullary cavity
What cell is in the lacuna of an osteon?
osteocytes
What is the endosteum made up of (what kinds of cells)?
osteoprogenitors, osteoblasts AND osteoclasts
What is the name of the canals that open between osteons?
perforating canals -- connect haversian canals
What is the tissue covering of bone called?
periosteum
What is the function of an osteoblast?
secretes organic components of the bone matrix
What is the term for the spongy bone inside flat bones?
the Diploe layer
What is the growth plate of a long bone called?
the metaphysis
What are canaliculi?
tiny canals extending within the bony matrix, from osteocytes to (usually) other osteocytes
What is the function of an osteocyte?
to maintain the bone matrix
What are the main supports in spongy bone called?
trabeculae
What is in the medullary cavity?
yellow bone marrow (starts out as red bone marrow)