skeletal system Flashcards
osteology
study of bone structure and the treatment of bone disorders
6 general functions
support
protection of internal organs
movement
maintains homeostasis between bone and mineral
hemopoiesis
store trigigcerides (fat) in yellow bone marrow
Hemopoiesis
process where red bone marrow produces red blood cells, white blood cells and platelets
Where does hemopoisis occure
pelvis, ribs, sternum, vertebrae, ends of arm and thigh bones, developing bones in the fetus
What 7 tissues make up bone
- blood connective
- bone connective
- adipose connective
- dense connective
- nerve tissue
- cartilage connective
- Epithelial tissue
How are bones classified
by their shape
sesamoid bone
small bones that develop in tendons for protection against wear and tear
example of a sesamoid bone
patella
Long bone
- greater in length than width
- slightly curved for strength
example of long bone
femur, ulna, tibia, fibula, humerus, phalanges, and clavicle
short bones
somewhat cubes shaped nearly equal in length and width
example of short bones
patella, tarsals, carpals
2 functions of flat bones
- protection
- provide surfaces for muscle attachment
irregular bones
don’t fit in other categories
example of flat bones
cranial, sternum, scapula, ribs
example of irregular bones
vertebrae, facial bones, hip bones
macroscopic structures of the long bone
- diaphysis
- epiphyses
- metaphyses
- epiphyseal plate
- articular cartilage
- periosteum
- medullary cavity
- endosteum
epiphyses
distal and prooxmial ends; top and bottom of bone
Diaphysis
bones shaft or body; main portion of the bone
metaphyses
region in mature bone where the diaphysis joints the epiphyses
epiphyseal plate
in growing bone; layer of hylain cartilage CT that allows the diaphysis to grow in length
articular cartilage
thin layer of hylain cartilage CT that covers the part of the epiphyses where the bone form a joint with another
function of articular cartilage
- reduces friction
- absorbs shock
Periosteum
outside of the bone very tough strength of dense irregular CT
function of the periosteum
- protects the bone
- assists in fracture repair
- contains bone forming cells that enable bone to grow in thickness but not in length
- helps nourish bone and tissue
- serves as a attachment for tendons and ligaments
medullary cavity
space in the center of the bone where yellow bone marrow Is formed
endosteum
thin layer that lines the medullary cavity and contains a single layer of bone forming cells
4 cells in microscopic structures
osteogenic cells
osteoblasts
osteoclasts
osteocytes
Osteogenic cells
unspecialized stem cells that form osteoblasts
what microscopic structure cell can divide and into what
osteogenic cells and they divide into osteoblasts
Osteoblasts
bone building cells
synthesize and secrete collagen fiber
osteocytes
maintain bones daily metabolism (exchange of nutrients and waste with blood)
Osteoclasts
huge cells serived from the fusion of as many 50 monocytes
what are monocytes
type of white blood cells found in the endosteum
what do osteoclasts release
powerful lysosomal enzymes and acids that digestive the protein and mineral components of the bone matrix
what is the breakdown of bone extracelluar matrix
resorption
what is another name for bone
osseous tissue
what bone makes up 80%
compact bone
what bone makes up 20%
spongey bone
what % of collagen fiber gives strength and flexibility in the matrix of bone
25%
what % of mineral salts are in the matrix of bone
50%
mineral salts give what is matrix of bone
hardness
what mineral salts are in the bone matrix
calcium phosphate and calcium carbonate
compact bone is what
strongest bone
what is compact bone in units
osteons
central canal
contains blood vessels, nerves, and lymphatic vessels
Concentric lamellae
located around central canal
rings of hardness calcifed extracellular matrix
lacunae (dark lines)
between the concentric lamellae
small spaces which contain osteocytes
canaliculi
- small channels radiating in all directions from lacunae
- contain extracelluar fluid and finger like process or osteosytes
what are the fuctions of canaliculi
- connect the lacunae to one another and with central canal
- provide rout for nutrients and oxygen to reach the osteocytes and also carry away waste
performing canal
means by which blood vessels and nerves from the periosteum penetrate compact bone
periosteum
outside tissue on the bone
what is spongey bone
light make up most of the bone tissue of short flat and irregualr shaped bones forms most of the epiphyses of long bones
where is spongey bone located
narrow rim around the medullary cavity of the diaphysis
what is spongey bone unit
trabeculae
what is trabeculae
irregular lattice structure of thin columns of bone
what does spongey bone not have
osteons
where do you find red bone marrow
in the spaces of the spongey bone
Ossification
process in which bone forms
how many Principle situations where ossification occurs
4
4 principle situations
- initial formation of bones in an embryo
- growth of bones during infancy until adult size is reached
- remolding of bones
- repair of fractures
what does remolding of bones mean
replacement of old bone with new bone throughout life
bone growth in length is related to what
the activity of the Epithelial plate
when bone grows in length new what forms
chondrocytes
chondrocytes from on…
the epiphesial side of the plate while the old chondrocytes on the diaphyseal side of the plate are replaced by bone
what does that allow
the thickness of the Epithelial plate to remain constant but the bone on the diaphyseal size increase length
what happens when adolence ends
the formation of new cells and extra cellular matrix decrease and eventually stops around age 18-25
at this point…
bone replaces all cartilage leaning a bony structure called epipheseal line and bone stops growing in length
epiphyseal plate
a hyaline cartilage plate located in the metaphysis of long bones where new bone growth occurs
Epiphyseal line
a raised ridge on a mature bone that marks the point where an epiphyseal plate has ossified and stopped growing
Bone remodling involves what 2 things
- resorption
- bone depiction
resorption
removal of minerals and collagen fibers from bone by osteoclyasts
deception
addition of mineral salts and collagen fibers to bones by osteoblasts
4 requirements for normal bone matabalism
- minerals
- vitamins
- hormones
- weight boring exercises
what minerals are required for bone matabalism
-flouride
-maganese
-magneisum
-phospherus
-calcium
what % of calcium does bone store
90%
what does calcium do for the bone
- transmission of nerve impulses
-muscle contraction - blood clotting
- cell division
-secretion by glands and nerve cells
-enzyme function
what vitamins are involved
A, K,B12,D,C
weight baring exercises
-walking
-running
-weight lifting
the stimulus will….
be a decrease in blood calcium
step 1
the parathyroid gland cells detect the lower calcium levels causing them to increase their production cyclin AMP
what is the receptor
parathyroid cells
what is the input
cyclic AMP
step 2
the gene for the parathyroid hormone within the nucleus of a parathyroid gland cell detects the increase production of cyclin AMP
what is the control center
gene
step 3
as a result parathyroid hormone synthesis speeds up and more PTH is released into the blood
what is the output
PTH
step 4
the present of higher level of PTH increases the number and activity of osteoclasts which steps up the pase of both resorption
what is the effector
osteoclasts
step 5
the resulting release of calcium from bone (Ca +2) into blood calcium levels to normal and homeostasis is restored
