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)