1 Flashcards
Bones are made of
Bone, cartilage, dense connective tissue I adipose) nerves
Skeletal system functions
Support, protection, body movement, mineral homeostasis, hemopoiesis, triglitende storage (yellow marrow)
Bone extracellularmatrix
15% water 30% collagen 55% crystallized mineral salts -calcium phosphate + hydroxyapatite
Mineralization
Calcification/hardenning of tissue novel collagen fibres
Osteoprogenitorcells
Differentiate-able
Osteoblasts
Forms bone extracellular matrix
Osteocytes
Mature bone cells, maintains bone tissue
Osteoclasts
Remodels bones, resorption of trabecular, breaks down extracellutur matrix ) cause calcium release
Compact bone
1 provides protection & support
Spongy bone
Light weight & support
Periosteal arteries penetrate:
Volkman’s canal (side)
Nutrient arteries cred) & nutrients blue) penetrate
Nutrient canal in the diaphysis,
When ? Osteogenesis & osteocalcification
Embryological and fetal development,m growth before adulthood, remodeling bones, heal fractures
- Mesenchyme -> intramembranous bone
Intramembranous bone formation (Flat BONES)
Replacement of membrane with flat bones
- Mesenchyme ->Endochondral ossification
->cartilage model -> calcification ->osteoblasts make bone-> osteoclasts make medullary cavity
Interstitial growth
Cell growth in elastic matrix
LENGTH
Appositional growth
Material is added (cells, matrix)
THICKNESS
Epiphyseal plates!
Also push long bone growth
- Ossification Center develops (osteoblasts secrete extra cellular matrix)
- Calcification, hardening and deposited calcium and salts
- Matrix becomes trabeculae and fuse to make spongy bone
- Mesenchyme makes Periosteum outside
FLAT BONES - intramebranous bone formation (skull, mandible, flat bones)
- Mesenchyme cells become chondroblasts and they make hyaline cartilage model
- Chondrocytes dive, growth of hyaline cartilage model
- Primary ossification Center is made - calcified cartilage is covered by bone
- Osteoclasts resort trabeculae and make medullary cavity
- Secondary ossification
- Form articular cartilage
Enchondral ossification of long bones
Bones are constantly remodelled based on their
Lines of stress
As one ages bone mass is lost from
Bone modelling, as resorption and deposition rates are disproportionate
Osteoporosis
Ostridge girl is white skinny and menopausal, she smokes, drinks, and have history of illness, she is also an athlete with low body fat, estrogen, menstration
She had less bone mass, POROS bones.
She needs to eat better, exercise, and have more estrogen and calcium or else
She will be weak, fragile, less collagen and have wedge shaped vertebrae hunchback
CALCIUM - POCKI
Low levels of calcium ( Calcium homeostasis negative feedback system)
Parathyroid glands secrete parathyroid hormone
Osteoclasts resorb bone
Calcium is released
Kidneys produce calcitrol
Intestines absorb Calcium
