DHUBS 1 - week 5

Question 1

what are the skeletal matters?

Answer 1

disease/genetics
hormone ablative therapy
spinal cord or nerve injury
surgery and rehabilitation
aging
microgravity
bone structure demand

Question 2

function of bones

Answer 2

structure, support and framework for musculature attachments
protection of internal and vital organs
allows and/or limits movement or rotation
storage of fats in hte yellow bone marrow
site of attachments for tendons and ligaments

Question 3

bones structure

Answer 3

cortical bone
cancellous
medullary canal

Question 4

how do long bones form?

Answer 4

endochondral ossification (6 steps)
1. Cartilage: stem cells – chondrocytes, make cartilage
2. Growth of cartilage: cells in centre burst, triggering calcification
3. Primary ossification centre: nutrients artery penetrates centre of cartilage. Bone mineral matrix covers the calcified cartilage forming spongy bone.
4. Medullary cavity: bone mineral is reshaped and remodelled to from medullary cavity
5. Secondary ossification centre: blood vesicles enter the epiphyses (around time of birth). Cancellous bone is formed but no medullary cavity
6. Formation of cartilage on the joints: cartilage

Question 5

what is the bone made up of

Answer 5

1. Organic collagen matrix – 10% of adult bone mass is collagen, provides flexibility
2. Inorganic mineral – 65% of adult bone mass called hydroxyapatite, an insoluble salt of calcium and phosphorus
3. Water – approximately 25% of adult bone mass
4. Trace amounts of magnesium, sodium and bicarbonate

Question 6

what cells made and remodel bone

Answer 6

osteoblasts
osteoclasts

Question 7

explain osteoblasts

Answer 7

are bone forming cells, found on the
bone surface. they make the collagen chains that will form the mature organic collagen matrix

matrix formation
secretes type 1 collagen
regulates mineralisation
positioned above osteoid matrix
differentiates to become osteocyte

Question 8

explain osteoclasts

Answer 8

digests bone
large multi-nucleated
exhibits ruffled border and clear zone
exhibits polarity with nuclei away from bone surface
high density of golgi stacks, mitochondria and lysosomal vesicles

Question 9

explain bone lining cells

Answer 9

flat, elongated cells
generally inactive
cover surfaces of inactive bone
thouhgt to be precursor cells to osteoblasts

Question 10

joint classification - two ways

Answer 10

according to structure
according to function/movement

Question 11

joint classification - structure

Answer 11

synovial joint (most common): articulating surfaces enclosed within a fluid-filled joint capsule
cartilagious joint (primary and secondary): articulating surfaces connected by catrilage
fibrous joint (suture): articulating surfaces connected by fibrous tissue

Question 12

joint classification - function/movement

Answer 12

diarthrodial joint: lots of movement, freely moveable
amphiarthrodial joint: little bit of movement
synarthrodial joint: almost no movement