Question | Answer |
Types of Cartilage | Hyaline, Fibrocartilage, Elastic |
Hyaline Cartilage | Most abundant type. Provides support through flexibility & resilience. Locations: Trachea, articular cartilage, epiphyseal plate, fetal skeleton. |
Fibrocartilage | Contains thick collagen fibers. Acts as a shock absorber. Locations: Intervertebral discs, menisci of knee, pubic symphysis. |
Elastic Cartilage | Contains highly branched elastic fibers. Provides flexibility. Locations: Auricle of the ear and epiglottis. |
Characteristics of Cartilage | Semirigid, weaker than bone. Flexible & resilient due to elastic fibers & water content. Avascular-receives nutrient supply through diffusion.` |
Functions of cartilage | Support soft tissues. Articular surfaces for joints. Provide a model for endochondral bone formation. |
Endrochondral bone | Bone made from cartilage. |
Structure of cartilage | CHONDROBLASTS produce matrix of cartilage. CHONDROCYTES are mature cartilage cells, reside in lacunae. EXTRACELLULAR MATRIX. PERICHONDRIUM made of dense CT, provides mechanical support & protection. Protective cover. |
Bone | Osseous connective tissue. Calcified extracellular matrix-calcium phosphate. |
Bone marrow | More red in children: building things. More yellow in adults: storing fat. |
Functions of bone | Support and protect: framework, protect vital organs. Movement: attachment sites for muscles. Hemopoiesis: red bone marrow-making blood. Storage of minerals & energy reserves: calcium phosphate, yellow bone marrow. |
Bone classification by structure | long, short, flat, or irregular |
Long bones | Long and skinny column. Diaphysis (shaft) and epiphyses (end). Exs: humerus, radius, ulna, metacarpals, phalanges, femur, tibia, fibula, metatarsals. |
Short bones | Cube shaped. Exs: carpals, tarsals, seamoid bones (patella). |
Flat bones | Sheets. Exs. Skull, scapulae, sternum, ribs. |
Irregular bones | Weird shapes. Exs.vertebrae, sacrum, coccyx, os coxa, ethmoid, sphenoid. |
Sesamoid bone | bone formed within a tendon from friction. Not born with it. Ex: patella |
Structure of Long bones | Compact bone, spongy bone, epiphysis, diaphysis, metaphysis, articular cartilage, medullary cavity, endosteum, periosteum, perforating fibers, nutrient foramen. |
Compact bone | Superficial bone tissue. Tightly bound. |
Spongy bone | Deep bone tissue. Full of stored stuff. Lighter |
Epiphysis | Ends of long bones. Regional term. |
Diaphysis | Shaft. Regional term. |
Metaphysis | Contains the epiphseal plate or line. Middle. Regional term. |
Epiphyseal plate vs. Epiphyseal line | Located in metaphysis. Growth plate. When you are growing in height it is hyaline cartilage. When the cartilage turns to bone, the plate becomes the epiphysial line. Can't grow anymore. |
Articular cartilage. | Hyaline cartilage covering the ends of bones within a joint. Cover top and bottom of long bones. |
Medullary cavity | Contains yellow marrow in adults and red marrow in children. |
Endosteum | Layer of cells lining the spongy bone and medullary cavity. Inside bone. Microscopic layer. |
Periosteum | Dense CT outer covering of bone. |
Perforating fibers | Attach the periosteum to the compact bone. |
Nutrient foramen | contains nutrient artery. hole. |
Cells of bone | Osteoprogenitor cells, osteoblasts, osteocytes, osteoclasts |
Osteoprogenitor cells | Stem cells derived from mesenchyme that become osteoblasts. All other bone cells come from these. |
Osteoblasts | Immature osteocytes that BUILD bone by secreting osteoid (organic part of the bone matrix). Decrease blood calcium levels. Gather calcium. |
Osteocytes | Mature bone cells that maintain bone matrix. Oversee. Reside in lacunae. |
Osteoclasts | Cells that CONSUME bone (bone resorption). Phagocytic cells using HCL & lysosomes. Increase blood calcium levels. |
Classification of bone by histology | Compact bone: AKA cortical bone. Solid, relatively dense, lined by the periosteum. Found in superficial regions. Contains osteons. Spongy bone: AKA cancellous or trabecular bone. Porous. Lined by endosteum. Found in deeper regions. |
Structure of compact bone | Osteon (Haversian system), Central canal (Haversian canal), Concentric lamellae, Osteocytes, Lacunae, Canaliculi, Perforating canals, Volkmann's canals. |
Osteon (Haversian system) | Basic structural and functional unit of bone. |
Central canal (Haversian canal) | Houses arteries, veins, nerves. |
Concentric lamellae | concentric rings of osseous connective tissue that surround the central canal. |
Osteocytes | Mature bone cells. Overseers of other bone cells. |
Lacunae | Cavities which house ostocytes. |
Canaliculi | Connect neighboring lacunae. Allow nutrints, minerals, gases, and wastes to travel between the central canal and osteocytes. Branches from osteocytes. (Compact bone). |
Perforating canals (Volkmann's canals) | Connect blood and nerve supply to central canal. |
Structure of spongy bone | Trabeculae, parrallel lamellae, osteocytes within lacunae, canaliculi. |
Trabeculae | Main structural and functional component. Form crisscrossing bars and plates for strength. |
Canaliculi | Provide nutrients to cells through diffusion. (Spongy bone). |
Osteogenesis | Creation of bone. Either Intramembranous ossification or Endochondral ossification. |
Intramembranous ossification | Bone growth within a membrane (mesenchyme). Forms flat bones of the skull, some facial bones, mandible, and clavicle. |
Endochonral ossification | Bone growth within cartilage. Turns fetal framework of hyaline cartilage into bone. Formation of most bones. Primary ossicfication center in diaphysis, secondary ossification center in epiphysis. Shaft made 1st. Ends after. Growth plate remains. |
Bone Growth | Occurs during childhood and adolescence. Interstitial growth (length) vs. appositional growth (thickness). |
Interstitial growth at the epiphyseal plates | 1. Chondroblasts near epipphyseal plate multiply; epiphysis is pushed away from diaphysis. 2. Chondrocytes enlarge; matrix calcifies. 3. Chondrocytes die & disintegrate. 4. Remodeling by osteoclasts. |
Simple fracture | AKA closed fracture. Bone doesn't pierce the skin. |
Open or compound fracture | Bone pierces the skin. High velocity. |
Stress fracture | Thin break from repetitive loads |
Pathologic fracture | Disease weakens bones. Ex: osteoporosis. |
Fracture Repair Steps | 1. Fracture hematoma (puddle of blood) forms 2. Fibrocartilage (soft) callus forms 3. Hard (bony) callus forms 4. Bone remodeled. Retain signs of injury: thickening. Blood acts as splint on broken bones. |
Osteomalacia (Rickets in children) | Soft bones. Leads to bowed legs. Vit. D deficiency. Calcium dificiency. |
Osteoporosis | Excessive bone resoption. Aged and post-menopause. Holes in bone. Osteoclasts more active than osteoblasts. |
Osteitis Deformans | AKA Paget's disease. Excessive osteoclast and osteoblast function. Bone is unstable and immature. Disorganized. Most common in os coxa, skull, vertebrae, femur, and tibia. Too thick in some areas and to thin in others. |