6-1. Bones and Skeletal Tissue Flashcards
What are the functions of bone?
- SUPPORT (for soft body tissues, gives body shape)
- PROTECTION (of delicate internal organs (eg. brain, heart))
- MOVEMENT (muscles use bones as levers to move body parts)
- MINERAL STORAGE (bones are reservoirs for calcium and phosphate)
- BLOOD CELL PRODUCTION (hematopoiesis; most blood cells are formed in bone marrow)
What tissues make up bones?
cartilage and bone tissue
Bones themselves are ___.
organs
What are the types of cartilage?
hyaline, elastic and fibrocartilege
What are the primary components of cartilage?
chondrocytes
extracellular matrix made of a jelly like ground substance with collagen and/or elastic fibers
no blood vessels or nerves
The embryonic skeleton is initial made of up __ and __, but most is soon replaced by ___.
cartilage and fibrous membranes; bone
Where is cartilage found in the adult skeleton?
regions where more flexibility is required
What are 5 places where hyaline cartilage is found in the adult skeleton?
- articular cartilage - covers ends of bones at movable joints
- costal cartilage - connects ribs to sternum
- laryngeal cartilage - framework of voicebox
- tracheal and bronchial cartilage - keeps airways from collapsing
- nasal cartilage - tip of nose
Where is elastic cartilage found in the adult skeleton?
external ear and epiglottis
Where is fibrocartilage found in the adult skeleton?
intervertebral discs
pubic symphysis
menisci of knee
What are some types of bone cells?
osteoblasts > osteocytes
osteoclasts
osteoblast
bone building cells that secrete matrix around themselves
osteocyte
mature bone cells that maintain bone matrix
osteoclasts
break down bone matrix from areas where it’s deteriorating
What is bone matrix made of?
inorganic parts - mineral salts (primarily calcium phosphate) in tightly packed crystals - make up 65% of bone by weight and give it hardness
organic parts - osteoid - made of ground substance and collagen fibers forming a framework for calcium salts
osteoid
organic part of the bone matrix, made from ground substance and collagen fibers
Why is bone porous?
carry blood vessels and nerves to supply nutrients
make bones lighter
Bone can be classified as either _ or _, based on _.
compact or spongey; the distribution and size of the pores
What are the classifications of bone (by shape)?
long bones
short bones
flat bones
irregular bones
long bones
longer than they are wide, consist of a shaft with two ends (eg. humerous, femur)
short bones
about equal in length and width, roughly cube shaped (eg. carpals)
flat bones
thin flattened but often a bit curved (eg. sternum, cranium)
irregular bones
bones that don’t fit the other categories (eg. vertebrae)
diaphysis
tubular shaft; thick collar of compact bone surrounding central cavity
medullary cavity
hollow cavity running length of diaphysis; filled with adipose in adults (yellow marrow)
epiphysis
enlarged end, filled with spongey bone inside; have a proximal and a distal epiphysis
periosteum
shiny white membrane covering outer surface except at joints
endosteum
membrane lining the internal bone cavities
articular cartilage
hyaline cartilage covering the epiphysis at joints
epiphyseal line
between the diaphysis and each epiphysis of an adult bone. it is what remains of the epiphysial plate
epiphysial plate
a region of bone growth in children
The _ lines the outer surface of bones except at _.
periosteum; joints
The _ lines the internal bone cavities.
endosteum
compact bone
dense tissue containing few spaces - found in the diaphysis of long bones, helping them to resist stress, and covers the surface of all bones
The diaphysis of long bones is made primarily of __.
compact bone
The epiphysis of long bone is filled with __
spongey bone
__ covers the surface of all bones.
compact bone
Haversian System (osteon)
structural unit of adult compact bone; elongated cylinder (“tree trunks”)
Volkmann’s Canals
carry blood vessels and nerves from periosteum to interior (horizontal)
Haversian Canals
rung lengthwise thru center of osteons, carry blood vessels (vertical)
lamellae
concentric rings of hard, calcified matrix around each Haversian Canal
lacunae
small cavities between lamellae where osteocytes are housed
canaliculi
tiny canals that connect osteocytes to each other and to Haversian Canals; provide routes for nutrients
spongy bone
found inside short, flat and irregular bones, and within the epiphyses of long bones
Short bones are made primarily of _.
spongy bone
Flat bones are made primarily of _.
spongy bone
Irregular bones are made primarily of _.
spongy bone
Spongy bone / contain Haversian Systems/osteons.
does not
trabeculae
needle like spikes of bone that form along lines of stress; spaces between are filled with red bone marrow (where blood cells are produced)
Osteocytes lie in lacunae within the trabeculae and are nourished directly by blood from capillaries in the surrounding endosteum
Short, flat and irregular bones all consist of thin plates of ____-covered ____ bone on the outside and ___-covered ____ bone within.
periosteum-covered compact bone
endosteum-covered spongy bone (called diploe)
