Bones and the Skeletal System Flashcards
skeletal system is made up of
skeletal bones, cartilage, ligaments, connective tissues
purpose of cartilage
help stabilize bones
purpose of ligaments and connective tissues
stabilize the skeleton
periosteum
CT surrounds each bone, links bones to other joints
functions of skeletal system
provide support, storage of minerals, blood cell production, leverage/movement, protection
provide support
framework for the attachment of other bones/organs
storage of minerals
calcium and phosphate ions
blood cell production
bone marrow produces RBC, WBC, platelets
leverage/movement
muscles pull on bones to produce movement and bones create the lever that they pull on
protection
organs are protects by bones (eg. skull, vertebrae, pelvic bones, ribs
location of hyaline cartilage
found on many joint surfaces and where joints meet each other (ribs, nose, larynx, trachea)
fibrocartilage location
intervertebral discs (dominantly), pubic symphysis, insertion of ligaments and tendons
elastic cartilage location
ears (cartilage in external ear), epiglottis
functions of cartilage
support soft tissues, surface at articulations, precursor models for bone growth
support soft tissues eg
airways, auricle of ear
surface at articulations
provides gliding/stabilizing surfaces
precursor model for bone growth
hyaline cartilage forms model skeleton for ossification
2 types of cartilage growth
interstitial growth, appositional growth
interstitial growth
grows within the cartilage iteself
process of interstitial growth
- chondrocytes within lacunae are stimulates to undergo mitosis
- two cells (chondroblasts) occupy single lacunae
- chondroblasts start to secrete new matrix and begin to push away from each other (each cell is now a chondrocyte)
- cartilage continues to grow in the growth plate
interstitial growth declines as
cartilage matures due to matrix being rigid and unable to expand
appositional growth
growth that occurs along that cartilage outer edge
difference in growth between appositional v interstitial
appositional = width, interstitial = length
process of appositional growth
- undifferentiated stem cells at internal edge of perichondrium begin to undergo mitosis
- new undifferentiated stem cells are produced to replace themselves and develop into chondroblasts which from cartilage matrix
- chondroblasts push apart due to the formation of matrix and then become chondrocytes with each occuping its own lacunae
appositional growth continues on periphery until cartilage is… and growth only occurs when
is mature, injury to cartilage
does appositional growth and interstitial growth occur at the same time?
yes
osteoprogenitor cell location
found on covering of bone, outer most layer, inner most layer of bone
osteoprogenitor cell purpose
involved in repair of bone after break
osteoblast location
inner and outer surface of bone
osteocytes purpose
maintain protein and mineral content of matrix
osteoclast
large multinucleated cells that secrete acids to dissolve bones to release calcium and phosphate ions into blood
osteolysis
taking bone apart and adding minerals back into bloodstream if needed
osteoblast v osteoclast activity
osteoblasts more active in children, osteoclasts more active in elderly
balance between osteoclasts/osteoblasts may be dependent on
diet
why is calcium needed in the blood stream?
regulates pH
makeup of bone
bone cells, collagen fibers, ground substance
calcium phosphate makes up
2/3 of bone mass
hydroxyapatite crystals provides
strength against compression and resistance to weight
2 types of osseous tissue
compact and spongy
what bone surrounds the medullary cavity
spongy bone
types of lamellae
concentric, interstitial, circumferential
concentric lamellae
form circles around central canals
interstitial lamellae
fragments of lamella that fill space between lamella
circumferential lamellae
lamella on bone surface (most superficial)
benefit of trabeculae
create strength to deal with stress from the side and form lightweight nature of bone
purpose of spongy bone
reduce weight of bones, allow for multidirectional force resistance, create space for red bone marrow
7 categories of bones
sutural, irregular, short, pneumatized, flat, long, sesamoid
where can sesamoid bones be found?
possible to develop at the joints where the fingers are in individuals who have gone through pubertal growth
external anatomy of long bones
diaphysis, epiphysis, metaphysis
diaphysis
elongated central part of long bones
epiphysis
enlarged area located on ends
what covers the epiphysis?
articular cartilage - reduces friction and absorbs shock when bones move at joint
metaphysis
thin segment of bone that connect diaphysis and epiphysis
external surface of long bone
periosteum
2 layers of the periosteum
outer fibrous layer, inner osteogenic layer
outer fibrous layer CT
dense irregular CT
outer fibrous layer purpose
protects bone
long bone internal anatomy
endosteum, medullary cavity, epiphysis, diaphysis
wall of diaphysis is made of
compact bone to protect and support
endosteum
thin membrane that lines inside of compact bone (contains osteoblasts, some CT)
medullary cavity
hollow space in the middle of the diaphysis
epiphysis is made of
spongy bone
proximal/distal epiphysis
expanded region closer/father to point of attachment
epiphyseal line
boundary of epiphysis that defines point of growth in bone
what cells are present in periosteum?
osteoprogenitor cells and osteoblasts
what cells are present in endosteum?
osteoprogenitor cells, osteoblasts, osteoclasts
what kind of tissue is the endosteum made of?
epithelial tissue (resides between bone CT and yellow marrow)
4 major sets of blood vessels associated with long bones
nutrient, metaphyseal, epiphyseal, periosteal vessels
larget blood vessel
nurtient vessels
where do nutrient vessels enter into?
medullary cavity/diaphysis
where do nutrient vessels come through?
nutrient foramen - opening in bone
nutrient vessel branches towards
epiphysis (ascending and descending branches)
metaphyseal and epiphyseal vessels
secondary, smaller, feed region of metaphysis and epiphyseal
metaphyseal and epiphyseal purpose
penetrate into bone to deliver oxygen/nutrients
periosteal vessels
travel along the periosteum and penetrate into bone to deliver oxygen/nutrients
