skeletal system p1 Flashcards
Five Primary Functions of the Skeletal System
- Support
- Storage
- Blood Cell Production
- Protection
- Leverage
components of skeletal system
bone, associated cartilage, ligaments, and others CT
other name for bone tissue
osseous tissue
what type of tissue does osseous tissue have?
- dense, supportive CT
- around collagen fiber
what does osseous tissue produce?
Produces solid matrix of calcium salt deposits
organic components of bones
- Cells
- Collagen fibers
- Ground substance
inorganic components of matrix
Primarily hydroxyapatite
-> Calcium phosphate and calcium hydroxide
Cells of Bone
- osteoprogenitor cells
- osteoblasts
- osteocytes
- osteoclasts
Osteoprogenitor cells
Mesenchymal stem cells in endosteum and periosteum
Osteoblasts
secrete osteroid
Osteoclasts
Secrete hydrochloric acid and enzymes that dissolve matrix
compact bone vs spongy bone
compact:
* External surfaces of long and flat bones
spongy:
- trabeculae
- internal surface of bone
what is the basic unit in compact bone?
osteon
Osteocytes are arranged in _________ ___________, around a ________ ________ containing blood vessels
concentric lamellae; central canal
structure of compact bone
- Circumferential Lamellae
- Periosteum
- Perforating fibers
which structure in compact bone is around long bone and bind osteon together?
Circumferential Lamellae
which structure is in the outside of compact bone, except joint capsules?
Periosteum
Perforating fibers
collagen
where can we find perforating fibers?
- bone
- periosteum
- joint capsule
- tendon/ligament
Endosteum
incomplete cellular layer
what structures are include in the endostenum?
- Covers trabeculae of spongy bone
1. Osteoblasts
2. Osteoprogenitor cells
3. Osteoclasts
how are bone classified by?
- Shape
- Internal tissue organization
- Bone markings (surface features; marks)
6 bone shapes
- Sutural bones
- Irregular bones
- Short bones
- Flat bones
- Long bones
- Sesamoid bones
Structure of a Long Bone
- diaphysis
- epiphysis
- metaphysis
which structure of long bone is a compact bone and have medullary cavity?
diaphysis
which structure of the long bone is a spongy bone?
epiphysis
where does diaphysis and epiphysis meet?
metaphysis
what does spongy bone have?
- no osteon
- trabeculae
- red bone marrow
medullary cavity
have yellow marrow
osteogenesis
bone formation
Calcification
process of depositing calcium salts
when does calcification occur?
during bone ossification and in other tissues
ossification
process of replacing other tissues with bone
Two main forms of ossification
- Endochondral ossification
- Intramembranous ossification
Endochondral Ossification
- Ossifies bones that originates as cartilage
- have 6 main steps
Growth in length at epiphyseal plate (from Epiphyseal to Diaphyseal)
- Zone of resting cartilage
- Zone of proliferation
- Zone of hypertrophy
- Zone of calcification
- Ossified bone
Summary of bone development
- Cartilage model forms
- Bone collar forms
- 1° ossification center
- Medullary cavity
- 2° ossification center
- Growth continues
what type of growth thicken and strengthen long bone?
appositional growth
when does bone stop growing?
in your early 20’s
how to determine someone is stop growing through x-ray picture?
Epiphyseal cartilage ossifies -> you cannot see it as epiphyseal line anymore
other name for Intramembranous Ossification
dermal ossification
which structure undergo intramembranous ossification?
Flat bones of the skull
Three main steps intramembranous ossification
- Mesenchymal cells differentiate to osteoblasts
- Osteoblasts begin ossification
- Spongy bone formation – remodeled
3 ways of blood supply of mature bones
- Nutrient Artery and Vein
- Metaphyseal Vessels
- Periosteal Vessels
which pathways supply blood for epiphyseal cartilage?
nutrient arteries and veins
which vessel does bone growth occur?
metaphyseal vessels
which pathways does blood supply to superficial osteons?
periosteal vessels
which pathways is the is the secondary ossification centers during development?
periosteal vessels
which cell types involve in bone remodeling?
-osteoblasts
-osteoclasts
-osteocytes
effect of exercise on bone
- allow bone to acclimate
- Stressed bones become stronger/denser
Bone Degeneration
Up to one third of bone mass
dietary source for bone growth
calcium and phosphate (in milk)
hormone stimulate bone growth
- calcitriol
- growth hormone
- thyroxine
where does calcitriol synthesis in?
in kidneys
what factor required for calcitriol?
vitamin D3
which mineral stimulates osteoblast activity ?
vitamin A
which mineral do the collagen synthesis/stimulation of
osteoblast differentiation ?
vitamin C
which mineral help synthesize bone proteins?
vitamin K and B12
what hormones are responsible for the sex differences in height?
Estrogens and androgens
what hormones responsible for calcium (ion) homeostasis?
Calcitonin and parathyroid hormone
Fractures
Cracks or breaks in bones
Fractures are repaired in four steps
- Formation of clot
- Formation of callus
- Ossification of callus
- Remodeling (to original look)
osteopenia
Bones become thinner and weaker with age (~30-40yrs old)
Osteoporosis
Severe bone loss
when does osteoporosis usually occur?
over age 45 -> usually more in women (during menopause)
