Hyaline Cartilage
stretchy and strong
- mid range, most common
- found in: nose, trachea, ribs, fetal skeleton, end of long bones
Fibrocartilage
strongest
-found in: intervertebral disc‘s, pubic symphysis, knee meniscus
Elastic cartilage
stretchiest
- found in: ear, epiglottis
Axial skeleton
lie along the long axis
- ribs, skull, vertebrae
Appendicular skeleton
limbs
- pectoral girdle, pelvic girdle
Long bones
longer than they are wide
- ex: humorous, tibia, femur
Short bones
cube shaped
- ex: patella, carpals
Flat bones
thin, flat and a bit curved
-ex: ribs, sternum, most of skull
Irregular bones
bones with complicated shapes
-ex: vertebrae, oxcoaxe
Functions of bones
- Support
- framework, cradles soft organs
- Protection
- encloses soft organs (skull, vital organs)
- Movement
- provide levers for muscles
- Mineral storage
- stores calcium and phosphorus
- Blood cell formation
- hematopoiesis (hollow part of bone)
Compact bone
dense outer layer
Spongy bone
honeycomb of trabeculae filled with yellow bone marrow
*trabeculae: little beams
Where is bone marrow?
stored in medulla cavity
What covers the ends of long bones?
articular cartilage
Structure of a flat bone
- Compact bone: outer layer of compact and spongy bone inside
- Spongy bone (diploë): in short, flat and irregular
Location of hemopoietic tissue
In red marrow and makes RBCs, WBCs and platelets
- infants : found medulla cavity and spongy bone
- adults: found in diploë, head of femur and humerus
> anemics can convert yellow to red marrow in need
Osteoclasts
large cells that absorb and
breakdown bone matrix
Osteoblasts
bone forming cells
- when is trapped in matrix it turns into osteocyte
Osteocyte
mature bone cells
Osteoid
unmineralized bone matrix
Lacuna
hollowed out space for osteocyte to live
Canaliculus
tiny canals nutrients diffuse from blood vessel in Haversion canal to osteocyte
Osteon
functional unit of bone
- Haversian system
Lamellae
hard nonliving part (matrix)
Perforating fibers
– AKA Sharpeys fibers
- connects periosteum to bone
blood vessel
continues into medullary cavity containing marrow
Central (Haversian) canal
hollow tube for blood vessel and nerve
- Parallel with long bone
perforating (Volkmanns) canal
Space for blood vessel and nerves
- perpendicular to long bone
What color is the marrow in spongy bone?
Red
Calcification
hardening and crystallization of bone matrix
- adding minerals to osteoid/matrix
Hydroxyapatites
mostly mineral salts like: calcium, phosphate and about 65% bone mass
- gives bone hardness and resistance to compression
Ossification
- Osteogenesis + Ossification: process of bone tissue formation
- leads to: formation of bony skeleton embryos, bone growth until adulthood, bone growth + thickness, remodeling + repair
Intra-membranous ossification
bone develops from fibrous membrane, flat bones in skull and clavicle
Endochondral ossification
bones forms by replacing hyaline cartilage, long bones, fetus formed this way
Lysosomal enzymes
- disgust collagen and organic material
Acid
dissolve bone minerals
Bone remodeling
Bone resorption followed by bone deposit
- osteoclasts > osteoblasts
Bone resorption
Osteoclasts bind to periosteum/endosteum to form a leak proof seal and secretes lysosome enzyme and acids
Bone deposit
Osteoblasts lay down new bone (osteoid)
Calcium
Important to have an adequate amount in bloodstream
Importance of calcium?
More important to keep calcium in bloodstream because of nerves impulses, muscle contractions, mitosis
Wolff’s law
- Bone becomes thicker/stronger to resist forces placed upon it (running and weights)
- Bones becomes thinner/weaker when no forces are acting on it (swimming, astronauts)
Developmental aspects of bone
Embryonic skeleton ossifies in a predictable timetable that allows fetus age to be easily determined
- at birth most bones are well ossified
- at 25 nearly all bones completely ossified and old age bone resorption predominates
Osteomalacia
inadequate bone mineralization caused by lack of calcium and vitamin D
- treated: add calcium and vitamin D in diet
Ricketts
inadequate bone mineralization in children
- treated: add calcium and vitamin D in diet
- can cause: bone deformities (bowed legs)
Osteoporosis
bone resorption outpaces bone deposit. bone turns weak/porous.
- treated: working out + vitamin D
- causes: kyphosis (hunchback)
- Why little old white women?
• Little- less weight on bones
• Old - post menopausal, lack of hormones and estrogen
• White- less vitamin D
• Women – less testosterone
Pagets
excessive bone formation and breakdown
FOP
- fibrous dysplasia ossifigous progressiva
- soft tissue can turn into bone tissues
• no known cure
Hypercalcemia
high levels of blood calcium.
- cause: kidney stones
Club foot
foot turns inward or sole of turns upward
- easily fixed
Carpal tunnel
repetitive finger movement
- treated: lower activity of fingers or surgery
Spina bifida
spine and spinal cord fail to develop properly (neural tube defect)
- caused by: folate deficiency, obesity, diabetes
Osteogenesis Imperfecta
brittle bone disease where bones don’t form properly. bones are weak, shatter easily, sometimes painful, blue sclera, trouble hearing
- Caused by in adequate collagen
- no treatment
Achondroplasia
type of dwarfism where head is normal size
- defective cartilage that interferes growth of long bones
- no cure
Osteosarcoma
bone cancer
-More common in young people because bone is still developing
Osteomyelitis
Bone infection