FOUND-HARC-THE SKELETON Flashcards
what are the 4 functions of the skeleton?
- support
- movement
- storage of minerals and ions
- production of blood cells
what are the two bone arrangements?
compact bone
trabecular bone
what are the characteristics of a compact bone?
- more dense
- very strong (compressive and tensile strength)
- only strong in 1 direction
- made up of osteons arranged in concentric circles of collagen fibres around a central canal-Haversian canal -contains blood vessels and nerves
- fibres run in 1 direction so very strong
what are the characteristics of trabecular bone?
- aka spongy bone
- made up of struts
- not as strong
- can take forces in different directions
- important in joints
- contains cross-links
what is a long bone?
bones which are longer than they are wide
what is the ossification?
process of bone formation where other tissues are replaced with bone
what are the 2 forms of ossification?
- endochondral (most common)-bone replaces existing cartilage model
- intramembranous-bone develops directly from mesenchyme or fibrous connecting tissue
what is cartilage and what is it made up of?
- flexible connective tissue
- made up of chondrocytes which produce and maintain the extracellular matrix-mainly collagen and some tissue fluid
what is the process of endochondral ossification?
1-chondrocytes increase in size while matrix calcifies around them-starves and kills chondrocytes
2-blood vessels grow into perichondrium and cells differentiate into osteoblasts-bone forming cells-bone begins to form around cartilage shaft
3-blood vessels and fibroblasts migrate into cartilage-fibroblasts differentiate into osteoblasts
4-wave of ossification spreads towards end of bone
-osteoclasts (bone resorbing cells) absorb bone from centre-leaving marrow cavity
-compact bone forms from periosteum as bone grows forwards and surrounds marrow cavity
5-capillaries and osteoblasts migrate into epiphytes and ossification begins-at secondary ossification centres-timing of this varies
what is an osteoblast?
bone forming cell
what are 2 types of cartilage growth?
- interstitial-growth from within growth plate
- appositional-chondroblasts secrete new matrix along existing surface-causes cartilage to expand and widen
what does an epiphyseal growth plate do?
allows interstitial growth
what is articular cartilage?
- smooth white tissue that covers the ends of bones where they come together to form joints
- cushions between bones and reduces friction-arthiritis
- does not grow bones
what are the types of growth of long bones?
-interstitial-high cartilage growth-results in lengthening of bone
what are 2 ways joints can be classes and explain
- structural-based on intervening tissue
- functional-based on range of motion
what are the types of structural joints?
- fibrous
- cartilaginous-primary-hyaline cartilage
- secondary-fibro cartilage
- synovial-no tissue between 2 bones-synovial fluid
what are the different types of functional joints?
- synarthrosis (syn=together)-fixed
- amphiarthrosis (amphi=both sides)-moves slightly
- diarthrosis (dia=through)-moves freely
what are intra-articular ligaments?
ligaments inside joint
what are intra-articular menisci?
fibrocartilage joint to cushion joint and malleable so moulds to bone to shape joint
what do intra-articular discs allow?
different movements to occur in joint cavity
what are intra-articular labra?
helps deepen joints for stability
what do bursae and fat pads do?
- also surround joints
- bursae-sacks of fluid reducing friction around joint
- fat pad reduces friction
how can you classify synovial joints?
• Number of articulating surfaces
- simple-between 2 bones
- compound-between more than 2 articular bone surfaces
- complex-joints with intervening articular disc or menisci
• Axes of movement
- Uniaxial-1 degree of freedom
- Biaxial-2 degrees of freedom
- multiaxial-3 degrees of freedom
• Shape of articular surfaces
- gliding/planar joints
- hinge joints
- pivot joints
- ellipsoid/condyloid joints
- saddle/sellar joint
- ball and socket
what are examples of fibrous joints?
- —->suture-predominantly in skull
- —->syndesmosis-inferior tibiofibular joint
- —–>gomphosis-tooth in bony socket
what are examples of primary cartilaginous joints?
- —->between diaphysis and epiphysis of bones
- —–>in skull between sphenoid and occipital at base of skull-allows growth
- —–>between 1st rib and sternum
what are examples of secondary cartilaginous joints?
- —–>intervertebral joints between vertebrae
- —->manubriosternal joint between body and sternum
- —–>pubic symphysis-between pubic parts of hip
what do synovial joints contain?
fibrous capsule and synovial membrane which secretes synovial fluid which coats the articular cartilage-reduces friction
what are the characteristics of gliding/planar joints?
- —->flat/slightly curved surfaces
- —–>surfaces slide across each other
- —–>small movement
- ——>rotation possible but often prevented by ligaments
what are the charactersitics of hinge joints?
—–>permits angular motion in a single plane eg elbow or knee
what are the characteristics of pivots?
——>permits rotation eg forearm-proximal radioulnar joint
what are the characteristics of ellipsoid joints?
- —–>oval articular face nestles within a depression in an opposing surface
- ——>angular motion in 2 planes-along or across the length of oval
- allows flexsion/extension/ abduction/adduction
what are the characteristics of saddle joints?
- —->2 surfaces fit like rider and saddle
- —–>concave angular rotation eg circumduction prevents rotation
what are the characteristics of ball and socket joints?
- —->round head sits within cup-shaped depression in another
- —–>all combos of angular and rotational movements including circumduction can be performed
