Skeletal Tissue Flashcards
What is the function of the Skeletal tissue?
Structural support and framework
What is the function of Levers?
Change direction of forces generated by skeletal muscle
What does Skeletal Tissue protect?
Delicate tissues and organs
What does Skeletal Tissue Store?
Minerals/Ca salts and lipids
What does Skeletal tissue do with blood cell production?
Red and White blood cells
What is Cartilage?
Supporting connective tissue
What is the Gelantinous matrix in cartilage?
Ground substance and fibres
What cells are in Cartilage?
Chondrocytes occupy lacunae
What happens with Poorly vascularised cartilage?
Exchange nutrients occurs by diffusion, heals slowly
Where is Cartilage derived from?
Embryonic mesoderm
What does Mesoderm produce?
Mesenchyme which forms cartilage bone and fibrous tissues
What seperates the Cartilage from surrounding tissue?
Perichondrium
What the are the 2 layers of the Perichondrium?
Outer fibrous irregular CT layer, Inner Cellular layer
What are the 3 Major types of Cartilage?
Hyaline, Elastic, Fibrocartilage
What does Hyaline cartilage consist of?
Translucent matrix
most common
What is hyaline cartilage covered by?
Dense perichondrium
What does matrix in hyaline cartilage contain?
closely packed collagen fibres
What does Hyaline cartilage do?
Provides tough but flexible support e.g connects ribs and sternum
What is articular cartilage?
Covers opposing bone surfaces e.g elbow
What does elastic cartilage contain?
Elastic fibres which are resilient and flexible, tolerate distortion and returns to shape
What is an example of elastic cartilage?
Epiglottis, larynx
What is fibrocartilage?
Little ground substance, matrix dominated by large collagen fibres which are densely interwoven
How is Fibrocartilage tough and durable?
Resists compressions, absorbs shocks and prevents damage of bones
What are the 2 mechanisms of cartilage growth?
Interstitial
Appositional
What is interstitial cartilage growth?
Chondrocytes undergo cell division to form additional matrix, enlarges cartilage from within (balloon)
What is Appositional cartilage growth?
New layers added to surface, inner layer of perichondrium undergoes division, increase cartilage by adding to outer surface
What is the appositional cell cycle?
Cells - immature chondrocytes - cartilage matrix - differentiate mature chondrocytes
What is the source of new cartilage cells?
Fibroblasts
What is the Key tissue in growing bones?
Hyaline cartilage - foetus
How do precursor bones develop?
Endochondral ossification
What is Osteogenesis?
Bone formation and growth, 6 weeks after fertilisation
What is Ossification?
Replacement of cartilage and CT by bone
What are 2 Major forms of ossification?
Endochondral
Intramembranous
What is endochondral ossification?
Bone replaces existing cartilage
What are the steps of endochondral ossification?
Begins near middle of shaft 1 centre of ossification, centre of Epiphyses (head) calcify - 2 ossification centre - Epiphyses - filled with spongy bone
What is Intramembranous ossification?
Bone develops from mesenchyme, stem cells within connective tissye differentiate osteoblasts, mesenchymal cells cluster and secrete matrix
What are Osteoblasts?
Calcification of mesenchymal cells
Where does ossification begin?
Ossification centre
What does I ossification first form?
Spongy bone, remodels to compact bones
What are examples of flat bones?
Skull,Clavicle
What does Bone contain?
Support Connective tissue, Specialised cells, extracellular fibres, ground substance, calcium phosphate, collagen, osteocytes
How is blood supplied to the bone?
Nutrient artery, Metaphyseal vessels, Periosteal vessels
What are long bones?
Long and slender - femur
What are short bones?
Small and boxy - carpals
What are irregular bones?
Complex, notches - pelvis
What are sesamoid bones?
Small flat, platella
What are sutural bones?
Flat bones of skull
What is the structure of Long bones?
Central shaft - diaphysis
End - epiphyses
Central - marrow cavity
Adjacent bones - articular cartilage
What are the 2 types of bone?
Compact and spongy
Describe compact bone?
Solid, surface of bone, diaphysis
Describe spongy bone?
Open network, interior, epiphyses
What cells are in a bone?
Osteocytes, mature cant divide - occupy a lacuna
What is a lacuna?
Pocket layers of matrix
What is canaliculi?
Passageways
What does osteocytes do?
Maintain normal function by recycling and repairing bone
What are Osteoblasts?
Precursor cells that make and release proteins and increase concentration of calcium
What are osteoprogenitor cells?
Stem cells that divide to make osteoblasts
What are Osteoclasts?
Giant cells, remove bone matrix, secrete acides and dissolve enzymes (osteolysis)
Regulate CA and Phosphate conc of body
What is functional unit of compact bone?
Osteon
Osteocytes arranged in concentric layers - osteon form cylinders surrounded by periosteum
What is Spongy bone formed from?
Lamellae form rods called trabeculae - frequent branching, nutrients reach by diffusion, red marrow here
What is Osteopenia?
Bones are thinner and weaker
Whatis Osteoporosis?
Function of bone compromised- hormones important