SKELETAL SYSTEM

• hematopoiesis 


  it is where bone marrow located
• osteoprogenitor cells


  develops into an osteoblast
• osteoblast


  lays down osteiods (collagen scafoid). it repairs the damage/destroyed bone.
• osteiod 


  made up of collagen which helps build up bone
• osteocytes 


  maintain the bones the daily metabolism. it is form from the traped osteoblast in osteiod.
• osteoclast 


  it is knows as bone destroying cells. It resorps the bone with sufficed boarder.
• synarthroses - provides strong connection between the adjacent bones

  amphiarthroses - joint that has limited mobility

  diarthroses - a freely movable joints


  what are the classifications of joints?
• epiphysis 


  it is the head of the long bone
• diaphysis 


  it is the shaft of ng bone
• metaphysis 


  part of bone contain the epiphyseal plate
• epiphyseal plate


  the main site of growth of long bone. when the bone stops growing, the growth plate becomes an epiphyseal line
• compact bone 


  also known as cortical bone, it is made up of osteon found under the periosteum and in the diaphyses of long bone. It provides strength and support.
• trabecular bone 


  spongy, porous material composed of hard and soft tissue components which can be found at the epiphyses and metaphyses. It reduce the bone weight.
• ossification 


  the process of creating bone, that is or transforming cartilage into bone.
• intramembranous ossification


  bones develop via direct osteoblast differentiation within the mesenchyme.
• endochondral ossification 


  occurs within the cartilaginous template and also within the surrounding fibroblastic perichondrial sheath to form the bone collar.
• interstitial growth


  bone growth in length. the process divided in 5 division. resting zone, prolification zone, maturation zone, calcification zone, and ossification zone.
• resting zone


  consist hyaline cartilage and codricytes
• proliferate zone 


  bone cells undergo mitosis
• maturation zone 


  lipids, glycogen, and alkaline phosphate accumulate, causing the cartilaginous matrix to calcify.
• calcification zone


   contain dead chondrocytes
• ossification zone


  osteoblast and vessels fill the empty spaces creating new bone.
• appositional growth 


  the increase in the diameter of bones by the addition of tiny bones by the addition of bone tissue at the surface of bones. Osteoblast at the bone surface secretes bone matrix, and osteoclast on the inner surface break down bone.
• bone remodeling 


  the removal of mineralized bone by osteoclast followed by the formation of bone matrix through the osteoblast that subsequently become mineralized
• kidney, bone, intestines 


  what are the 3 organs present in calcium homeostasis
• parathyroid hormone 


  this hormones is release when the calcium level is to low (hypocalcemia). The parathyroid chief cells release this hormones in response to low level of calcium in blood. In response to kidney, it increase the calcium reabsorption from urine. It stimulates the release of calcium from bones into the bloodstream, in response of bone. While the intestines, stimulates the conversion of vitamin D; calcium absorption from food.
• calcitonin 


  This hormones response in the high level of calcium in blood (hypercalcemia). Its role if to lower the calcium level in blood:

  bone -  this hormones block the activity of osteoclast (destroying bone)

  kidney - it increase the calcium reabsorption, which increase the amount of calcium excreted in urine
• endochondral ossification

  • formation of bone collar in hyaline cartilage model
  • cavitation of the hyaline cartilage
  • invasion of internal cavities (blood) and osteoblast
  • as the osteoblast invasion it will now start to form the medullary cavity (gap in primary center)
  • and last is the ossification of epiphyses leaving only a little hyaline cartilage.
• medullary cavity


  a hallow part of bone that contains bone marrow. In child the gap is filled with red blood cells and for adult it turns into yellow marrow