Connctive Tissue Flashcards

Question

Describe the microstructure of compact bone

Answer 1

• Outer layer is called periosteum • Contains osteons which are parallel tube shaped structures containing blood vessels and nerves (within the central/Haversian canal) ◦ Aligned the same way force is applied to the bone • Each central canal is linked to other canals via perforating canals • Lamellae are located around the osteons • Between adjacent lamellae of the osteon are little cavities called lacunae ◦ Within each lacuna is an osteocyte

Answer 2

• Spongy bone has a less compact structure (resembling honeycomb) • Contains osteocytes within lacunae but not arranged in concentric circles • Consists of trabeculae which are lamellae that are arranged as rods or plates • Spaces in between contain red bone marrow (which produces blood cells)

Answer 3

Rods of cartilage (cartilage models)

Answer 4

Tender models

Answer 5

Membrane models

Answer 6

• Osteoblasts secrete osteoid which gradually replaces the cartilage model • Calcium and phosphate salts are deposited through the cartilaginous osteoid and increasingly calcify the cartilage model • Ossification begins at the ossification centre • At around 8 weeks, you get the development of a bone collar • The blood supply then starts to develop and bone tissue replaces cartilage as the osteoblasts secrete osteoid into the shaft of the long bone • Ossification continues and spreads to the epiphyses, resulting in bone lengthening • At the time of birth, the secondary centres of ossification develop in the epiphyses and the medullary canal/cavity forms by the osteoclasts breaking down bone tissue in the centre of the shaft • The long bones continue to grow during childhood (which occurs at the growth/epiphyseal plate) and the plate produces new cartilage on the surface which is then converted into bone (lengthening the bone) • During puberty, cartilage growth slows down (meaning there’s more bone deposition in the epiphyseal plate) • This causes the whole plate to be gradually converted into bone over time so no more lengthening is possible

Answer 7

Bone density changes in response to the forces placed on the bone

Answer 8

Around 10%

Answer 9

• Synarthroses (immovable e.g. joints between bones in the skull) • Amphiarthroses (slightly moveable e.g. joints between adjacent vertebrae) • Diarthroses (freely moveable e.g. knee joint)

Answer 10

• Uniaxial (movement in one plane) • Biaxial (movement in two planes) • Multiaxial (movement in three planes)

Answer 11

• Fibrous • Cartilaginous • Synovial

Answer 12

• Sutures • Gomphosis • Syndesmosis

Answer 13

• Permits no movement (only found where bones of the skull meet each other) • Bone edges are serrated and are united by a layer of fibrous tissue • Periosteal layers of the bone are continuous

Answer 14

• A peg fits into a socket and is held in place by a fibrous band or ligament • E.g. where roots of teeth are held in their socket by dontal ligaments

Answer 15

• United by a larger amount of fibrous tissue via a ligament or an interosseous membrane (e.g. between radius and ulna) • Movement allowed is due to the flexibility of the membrane or stretching of the ligament • Movement is quite restricted and controlled

Answer 16

• Synchondroses • Symphysis

Answer 17

• Bones are untied by a continuous layer of hyaline cartilage • Temporary • Only example of this joint in adults is the first sternocostal joint • In kids, it can be found at the epiphyseal growth plate

Answer 18

• Articulating surfaces of the bones involved are covered in hyaline cartilage and also have a pad of fibrocartilage between them (e.g. between vertebrae) • Allows a small amount of controlled movement to take place

Answer 19

• Articulating surfaces of the bones are covered in an articular hyaline cartilage (allowing bones to move against one another with minimal friction) • There is a fibrous joint capsule that attaches at or away from the margins at the joint (strengthened by the muscles and ligaments that cross the joint) • Deep surface of the capsule is lined by the synovial membrane (which secretes synovial fluid into the joint cavity)

Answer 20

• Gliding joint (plane joint) • Hinge joint • Pivot joint • Ellipsoid joint • Saddle joint • Ball and socket joint • Condyloid joint

Answer 21

◦ Gliding joint (plane joint) ‣ Joint surfaces are relatively flat and are roughly equal length ‣ Some movement is possible by one bone gliding or twisting against the other ‣ E.g. sternoclavicular joint ◦ Hinge joint ‣ Allows movement about one axis only ‣ Good congruency of the joint surfaces (fit each other nicely) ‣ E.g. elbow joint ◦ Pivot joint ‣ Movement occurs at a single axis with one bone rotating around another within a fibro-osseus ring ‣ E.g. joint at the top of the spine where atlas meets axis (Atlanto-axial joint) ◦ Ellipsoid joint ‣ Similar to ball and socket joint but the surfaces are ellipsoid ‣ Movement is only possible about two perpendicular axes ‣ E.g. radio-carpal joint at the wrist ◦ Saddle joint ‣ Two surfaces are reciprocally concavo-convex ‣ Like a rider sitting on a saddle ‣ Allows movement to occur primarily about two perpendicular axes ‣ Usually allows a small amount of movement about a third axis ‣ E.g. Carpo-metacarpal joint of the thumb ◦ Ball and socket joint ‣ Ball of one bone fits into the socket of another bone ‣ Multiaxial joint (capable of movement in multiple planes and at least three axes) ◦ Condyloid ‣ Modified ball and socket joint ‣ Allows active movement about two perpendicular axes ‣ Passive movement could occur about a third axis ‣ E.g. metacarpal-phalangeal joints

Answer 22

The specific movement of joint surfaces

Answer 23

• Roll, spin and slide/glide