connective tissue 2

Question 1

bone

Answer 1

specialised connective tissue where ECM (osteoid) has become mineralised with calcium phosphate crystals to provide compressive strength

Question 2

compact bone

Answer 2

AKA dense bone
around edge of bone shaft
has support cells - osteocytes in lancunae
other cavities containing bv

Question 3

transport in bone

Answer 3

mineral prevents free diffusion

small channels - canaliculi provide a pathway for diffusion of O2 and nutrients from bv to osteocytes

Question 4

arrangement of bone

Answer 4

in osteons or Haversian systems with central canal containing bv with ECM arranged in concentric layers around the canal
collagen fibres arranged differently in each layer to provide additional strength

Question 5

central part of the bone

Answer 5

spaces between bone tissue
known as spongy/cancellous bone
bony structures are called trabeculae and arranged so they resist mechanincal stresses on the bone
space between trabeculae is filled with bone marrow
may be fat cells

Question 6

bone formation and removal

Answer 6

made by osteoblasts
resorbed by osteoclasts
in balance
deposition can be altered to increase strength or heal wound
net production in growth, net resorbtion because of disuse/osteoporosis
under hormonal control from calcitonin and PTH to maintain conc of Ca and phosphate

Question 7

start of bones

Answer 7

most as cartilage precursors in foetus
converted to bone
endochondrial ossification
in long bones cartilaginous region persists at growth plates between shaft and heads until bone reached adult length

Question 8

cartilage in adult bones

Answer 8

lines the bone surface where it forms part of the joint

Question 9

what lines the bone

Answer 9

dense connective tissue

periosteum

Question 10

action of skeletal muscle

Answer 10

act across a joint to move one bone in relation to another

Question 11

muscle

Answer 11

made of myofibrils - each with nuclei around perimeter

around myofibril is ECM containing collagen fibres -continuous with those of tendons or bones on which the muscle acts

Question 12

formation of muscle

Answer 12

made form large number of precurser cells

fuse to make syncytium - contractile apparatus in cytoplasm becomes continuous

Question 13

cardiac muscle

Answer 13

muscle cells remain separate

connect end to end at intercalated discs

Question 14

smooth muscle

Answer 14

individual cells, 100s um in length
have central nucleus, cigar shape - circle in transverse
not powerful of rapid contraction, but can contract to a smaller fraction of relaxed length and maintain contraction for longer