LO4

• What are the functions of the skeletal system?

  Support, protection, movement, hemopoiesis, storage of mineral and energy reserves 
• How are bones classified based on their shape?

  Long bones, short bones, irregular bones, and flat bones 
• process

  outgrowth of larger body
• Ramus

  arm or branch of a bone
• Trochanter

  protuberance on bone that muscles are attached to
• Tuberosity

  rounded prominence that muscles are attached to
• Tubercle

  small rounded protuberance on surface of bone
• Facet

  smooth area on bone usually covered by articular cartilage
• Fossa

  depression or hollow in bone
• Foramen

  opening in a bone
• Fissure

  groove in a bone
• What are the structural components of a long bone and why are the right proportions of these components important?

  Proximal epiphysis, metaphysis, diaphysis, metaphysis again, and distal epiphysis.

  Diaphysis gives strength and support to the bone. Epiphysis allows attachment of muscles, tendons, and ligaments. Periosteum protects bone growth and repair.
•  Compare and contrast compact bone with spongy bone.

  Compact bone is dense and strong that provides support and protection. Found in shafts of long bones 

  Spongy bone is lighter and less dense compared to compact bone and has a honeycomb like structure.
• What is an osteon, and what are its components?

  Osteon is a unit found in a compact bone that can also be called a haversian system.

  Lamellae, central canal, lacunae, canaliculi, and perforating canals.
• What is the function of red marrow in the bones and how does it differ in adults and infants?

  Red marrow is responsible for making red and white blood cells, and platelets. In infants, red marrow is found in almost all the bones but for adults it’s more limited and concentrated on certain bones.
• Osteoblasts

  secrete the matrix for bone formation and are cells by the osteoprogenitor
• Osteogenesis

  process of bone formation that’s started by osteoblasts
• Osteoid

  contains collagen protein and semi solid ground substance of proteoglycans and glycoprotein and only made up of organic components. Produced by osteoblasts.
• Osteoclasts

  the cells that degrade bone to initiate normal bone remodeling and mediate bone loss in pathologic conditions by increasing their resorptive activity
• Osteolysis

  process where osteoclasts are digesting bone tissue
• How do osteocytes communicate?

  Through canaliculi which are connected through lacunae. Osteocytes can exchange waste products, nutrients, and chemical signals with each other.
• Endochondral ossification

  1. Future bone structure is made up of hyaline cartilage

  2. Blood vessels grow in the tissue and begin to innervate

  3. Mesenchymal cells begin to change to osteoblasts that produce osteoids

  4. Chondrocytes begin to hypertrophy, which produce larger holes in the matrix

  5. Bone collar forms when a layer of osteoid around the calcified cartilage hardens

  6. Perichondrium becomes the periosteum, later chondrocytes continue to become larger, forming the medullary cavity, the primary ossification site

  7. Medullary cavity is further vascularized and innervated
• Endochondral ossification

  The process by which most bones of the skeleton are created
• Endochondral ossification starts in 8-12 weeks of fetal development
•  What is the epiphyseal line?

  Epiphyseal line is a mark on a bone that shows where it used to grow, growth plates help bones grow and get longer and humans get older, it turns into a bony line called epiphyseal line.
• What are the factors affecting bone remodeling?

  Growth, thyroid, sex hormones, glucocorticoids, and serotonin
• Growth of a long bone

  1. Resting cartilage

  2. Proliferating cartilage

  3. Hypertrophic cartilage

  4. Calcified cartilage

  5. Ossification
• Long bone growth

  • Lengthwise growth
  • Widthwise growth
• Growth plate

  Area where lengthwise growth occurs
• Resting cartilage zone

  Inactive chondrocytes secure the bone's end
• Proliferating cartilage zone

  Cells rapidly multiply
• Hypertrophic cartilage zone

  Cells stop multiplying and grow larger
• Calcified cartilage zone

  Minerals harden the cartilage
• Ossification zone

  New bone tissue is laid down on the old cartilage
•  What is the effect of mechanical stress on bone?

  Bones respond to stress but making themselves denser and stronger and they experience micro damage from things like weight lifting. Osteoblasts build new bone tissue to repair and make those areas that were stressed stronger.
•  How do bones respond to mechanical stress?

  The get micro damage from activity but they repair and make those areas stronger + denser 
• Describe the role of vitamins A and C in the formation of bones.

  Vitamin A makes osteocytes that build new bone tissue and osteoclasts that are involved in breaking down old bone tissue. Its role is the balance between bone formation and bone resorption. 

  Vitamin C is for synthesis of collagen and gives a structural framework for bones to help strengthen and give flexibility. Without vitamin C, it leads to weakening of bone structure.
• Which organs are involved in the production of vitamin D?

  Skin, liver, and kidneys
• How do the following hormones affect the bones

  1. Growth hormone

  2. Thyroid hormone

  3. Glucocorticoids

  4. Serotonin
• Growth hormone

  Triggers the growth of cartilage in the epiphyseal plate that leads to long bone growth