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Anatomy_Unit2
Question | Answer |
---|---|
Interstitial Growth means | The process of growing LONGER (elongate) |
Apositional Growth means | The process of growing WIDER (widen) |
Irregular shaped bones do this | BOTH Intramembranous and Endochondral Ossification |
Intramembranous Ossification | *Forms mainly FLAT bones of skull *Bone develops BETWEEN layers of fibrous membrane *Can be seen in FONTANELS (baby's soft spots) |
What is the lineage of BONE cells? | Mesenchyme OsteoPROGENITORS OsteoBLASTS OsteoCYTES |
Embryonic Connective Tissue cells change into _______________ to form bone | Osteoblasts |
What are the steps for Intramembranous Ossification? | *Mesenchymal cells differentiate into osteoprogenitors *The osteoPROGENITORS then differentiate into osteoBLASTS *OsteoBLASTS lay down OSTEOID *Osteoid forms SPICULES that then differentiate into TRABECULAE *Trabeculae then form SPONGY bone *ENDOSTEUM then forms around the spongy bone *Spongy Bone then gets remodeled into COMPACT bone PERIOSTEUM forms around compact bone |
Any connective tissue (fluid, supportive, CT proper) starts with what? | Embryonic Connective Tissue or Mesenchyme |
Endochondral Ossification | *Forms mainly LONG BONES of body (especially appendages) * CARTILAGE MODEL formed first (like rubber dog bone) *Bone replaces cartilage over time *Some cartilage remains at EPIPHYSEAL (GROWTH) PLATE (until growth ends) and ends of bone (for life) *DIAPHYSIS is the primary center of ossification |
What are the steps for Endochondral Ossification? | *Mesenchyme cells differentiate into CHONDROBLASTS *Chondroblasts lay down CHONDRIN by infusing cartilage fibers with lots & lots of water until they fuse together *Build more & more chondrin & increase the length & thickness of the hyaline cartilage model (Interstitial). *Chondroblasts get stuck in lacunae and create CHONDROCYTES that will maintain the cartilage matrix *Will lay down so much that you have your bone that is completely made of hyaline cartilage. *Finishing off will form a PERICHONDRIUM |
What is hyaline cartilage like? | A wet, lubricated water balloon that is excellent for shock absorption |
Secondary Center of Ossification is where? | Proximal and distal epiphyses |
Bone growth | Throughout life bone continues to grow in length & width until 15-20 years old but will continue to RE-FORM bone *SPONGY BONE is replaced every 4 years COMPACT BONE is replaced every 10 years |
Appositional growth | *like tree rings *Bone cells lay down new bone tissue along the outside of the bone (deep to the PERIOSTEUM) *Bone cells also break down deep to the ENDOSTEUM |
Interstitial growth | *Bone replaces cartilage, where cartilage cells have died *Occurs along EPIPHYSEAL (growth) plate in both the PRIMARY and SECONDARY growth plates |
Irregular Bone Formation | *Often includes BOTH endochondral and intramembranous ossification *Many bones we view as a single bone in adults actually develop in multiple pieces *Examples of this are: sphenoid, ethmoid, many cranial bones, vertebra, and coxal bones *Vertebrae don't finish their fusions until your mid-20's *Intramembranous ossification happens first, then endochondral ossification |
Osteoporosis | Porous bone |
What occurs in osteoporosis? | *An imbalance of bone cells *Bone broken down faster than bone is formed (OsteoCLASTS break down bone faster than osteoBLASTS lay down bone) *On the INSIDE of the bone *WEIGHT-BEARING bones most commonly affected, such as the femur, tibia, & vertebrae |
Who has the propensity for osteoporosis? | *Anybody, but lately is increasing in YOUNGER women (since the 80's *Usually in ELDERLY women after MENOPAUSE *SMALL, THIN people. WHITE or ASIAN at increased risk *Family history *Cancer patients because cancer cells stimulate OSTEOCLASTS and whether the treatment causes depletion of OSTEOBLASTS (that break down bone) |
How does one prevent osteoporosis? | *Increase strength training *Drink more milk or fortified juice *Eat DARK, LEAFY GREENS (kale, spinach, etc) *Dandelion greens have the optimal ratio for CALCIUM/PHOSPHATE |
FLAT bones | Cranial skull bones, such as PARIETAL |
LONG bones | Bones of appendages, such as FEMUR, HUMERUS, etc |
SHORT bones | CUBE-like bones of wrist; such as CARPALS, TARSALS |
IRREGULAR bones | VARIABLE ("TRASH CAN") shape; such as vertebrae, hips, and coxal *Do both INTRAMEMBRANOUS and ENDOCHONDRAL ossification |
SESAMOID bones | SESAME SEED shape; such as the PATELLA (knee cap) *Develop with soft tissues and within TENDONS of muscles and what they do is help INCREASE the FORCE of that muscle. |
Function of the Skeleton 1 | SUPPORT of the soft tissues of body |
Function of the Skeleton 2 | *MINERAL RESERVOIR (calcium / phosphate) *98% of body's calcium is in bones |
Function of the Skeleton 3 | *ENERGY STORAGE: (Yellow, Older Marrow) *Fat stored in the MEDULLARY CAVITY of the long bones |
Function of the Skeleton 4 | *BLOOD CELL PRODUCTION (Red, Younger Bone Marrow) *Red bone marrow in cavities of SPONGY BONE |
Function of the Skeleton 5 | *Protection of VITAL ORGANS |
Function of the Skeleton 6 | LEVERAGE and MOVEMENT |
Mesenchyme | Embryonic Connective Tissue (looks like CT Proper) |
Mesenchymal Lineage | Mesenchyme begat CT PROPER, SUPPORTING CT, AND FLUID CT; CT Proper begat DENSE REGULAR & ADIPOSE; Dense Regular begat FIBROBLASTS which became FIBROCYTES; Adipose which became ADIPOCYTES; Supporting CT begat CARTILAGE and BONE; Cartilage begat CHONDROBLASTS which became CHONDROCYTES; Bone begat OSTEOBLASTS which became OSTEOCYTES; Fluid CT begat BLOOD |
Cartilage Characteristics 1 | *NO Blood Vessels or Nerves *Gas / Nutrients diffuse to cells from BV surrounding *Chondrocytes adapted to low O2 |
Cartilage Characteristics 2 | *Consists primarily of WATER (60-80 %) *RESISTS compression *Good at shock absorption |
Cartilage Characteristics 3 | *Surrounded by PERICHONDRIUM *Not around fibrocartilage *Like a GIRDLE holding things in place *AVASCULAR; helps in GROWTH & REPAIR *Provides GAS & NUTRIENTS to CARTILAGE CELLS |
More Cartilage Characteristics | *Growth ENDS at 18-20 years of age *Little HEALING in adulthood *Collagen RESISTS tension *POOR at resisting "SHEARING FORCES" (most common type of injury) |
Different Types of Cartilage CELLS | *ChondroBLASTS (Immature cartilage cells) *ChondroCYTES (Mature, dividing cells trapped in lacunae) |
Different Types of Cartilage | *HYALINE *ELASTIC *FIBROCARTILAGE |
Hyaline Cartilage | *Most ABUNDANT *Has FIBERS (too small to see) *LOCATED on end of bone (articular surface), growth plate, and costal cart (ribs) *MAINTAIN cartilage in certain areas in the articular surfaces (for SMOOTHER gliding) |
Elastic Cartilage | *MANY elastic fibers *TOLERATES repeated bending, recoil *Located within EARS, NOSE, EPIGLOTTIS *Looks like hyaline but has many more elastic fibers *Found in structures that need to bend |
Fibrocartilage | *ABUNDANT collagen fibers *RESISTS twisting & compression (REALLY STRONG) *NO perichondrium *LOCATED in Intervertebral discs, menisci *Looks similar to Dense Regular - look for chondrocytes in lacunae (EYEBALLS) *In structures with lots of IMPACT |
Gross Anatomy of OSSEOUS TISSUE (bone) | *Articular Cartilage *Spongy Bone *Proximal Epiphysis *Epiphyseal Line (scar) *Periosteum *Endosteum *Diaphysis (shaft) *Compact Bone *Medullary Cavity (or Marrow Cavity) *Distal Epiphysis |
Trabeculae | Bony projections |
What THREE structures do bones have? | *Blood Vessels *Nerves *Lymphatic Vessels |
What TWO types of OSSEOUS tissue does every bone have? | *Spongy *Compact *They have the SAME matrix and bone cells |
Structures WITHIN Spongy & Compact Bone | *Concentric Lamellae *Interstitial Lamellae *Trabeculae of Spongy Bone *Capillary *Small Vein *Circumferential Lamellae *Osteons *Periosteum *Lacunae with Osteocytes *Artery *Central Canal *Perforating Canal *Canaliculi |
Characteristics of Compact Bone | *Bone forms CONCENTRIC rings of MATRIX (osteon) *Bone cells are TRAPPED within cavities (lacunae) *Organized "NESTED RINGS" in periphery of bone *Replaced EVERY 10 years (like a passport) *Arrangement of collagen fibers are perpendicular to each other (allows for flexibility) |
Canaliculi Transfer | *Mineralized Matrix - NO diffusion through the matrix *Protoplasmic (arm) extension of adjacent cells connect within canaliculi *Waste, nutrients, gasses, etc. diffuse from cell to cell |
Characteristics of Spongy (Cancellous) Bone | *Honeycomb-like network of bone *Form TRABECULAE (beams) to resist directional stresses *Cavities filled with RED BONE MARROW *FOUND in epiphysis & center of bone organ *Lots of empty space and looks porous *REPLACED every 4 years |
Beams of Bone | *Allows COMPRESSION down MEDIAL DIAPHYSIS *Allows TENSION along LATERAL DIAPHYSIS MEDIAL = COMPRESSION LATERAL = TENSION |
Changing from Spongy Bone to Compact Bone | *Bone formation at the surface of the bone produces ridges that parallel a blood vessel *The ridges enlarge and create a deep pocket *The ridges meet and fuse, trapping the vessel inside the bone Compact bone can always change back to spongy bone. |
Micro-Anatomy of Bone | *Bone is a "supporting connective tissue" specialized within a matrix *Bone cells within Osteoid |
Non-Cellular Matrix (Osteoid): ORGANIC COMPOUNDS | *Provides FLEXIBILITY (won't just snap) *Primarily COLLAGEN FIBERS *Resists TWISTING & TENSION |
Non-Cellular Matrix (Osteoid): INORGANIC COMPOUNDS | *Provides DURABILITY & HARDNESS *Calcium & Phosphate thru our eating *98% of calcium is in our bones |
Bone Cells: SPECIALIZED CELLS | *OSTEOBLAST *OSTEOCYTE *OSTEOCLAST *OSTEOPROGENITOR |
osteoBLAST | *Immature bone cells *Secretes new matrix (osteoid) *Comes from MESENCHYMAL stem cells |
osteoCYTE | *Mature bone cells *Trapped cell in lacunae *"Resident" cell *Comes from MESENCHYMAL stem cells |
osteoCLAST | *Aren't part of the "Osteo lineage" and may be derived from WBC's (from leukocytes) *BREAKS down old matrix (osteoid) *RELEASES calcium & phosphate dissolving bony matrix *Do OPPOSITE of osteoblasts |
osteoPROGENITOR | *Will form all new bone cells *Can divide (MITOSIS) *Are part of the lineage *Comes from MESENCHYMAL stem cells |