Musculoskeletal System

Question 1

Epiphyses

Answer 1

• contains spongy bone

- filled with yellow or red marrow

Question 2

Diaphyses

Answer 2

• contains yellow bone marrow within medullary cavity

- endosteum within medullary cavity

Question 3

Periosteum

Answer 3

• Fibrous membrane covering bone
• contains small BV and osteoblasts → forms inner layer of growing bones
• periosteal fibres penetrate underlying bone → weld structures tgt
• BUT periosteum not firmly attached to underlying bone in kids

Question 4

location of the types of bone in long bones

Answer 4

external compact

internal spongy

Question 5

features of short/fat/irregular bones

Answer 5

• periosteum covers compact bone
• endosteum covers spongy bone inside
• bone marrow b/w trabeculae

Question 6

what consist of the bone tissues

Answer 6

consist of cells, fibres, extracellular matrix

Question 7

bone cells

Answer 7

osteoblasts: builds
osteoclasts: destroy
osteocytes: large inactive mature cells

Question 8

calcification of inorganic extracellular bone matrix

Answer 8

ca, mg, po4 crystals

• contributes to bone hardening/calcification
• effective at resisting stress and mechanical deformation

Question 9

calcification of organic extracellular bone matrix

Answer 9

collagen, mixture of protein/sugar (ground substance)

- adhesion b/w cellular and fibrous components → inc str and resilience of bone

Question 10

microscopic structure of bones

Answer 10

compact bone = 80% mass

• structural units = osteons
• cells cemented → allows delivery of nutrients AND imprisonment of bone cells

spongy bone = 20%

• no haversian system
• but has trabeculae network → inc tensile str
• orientation of network differs according to load and str

Question 11

what structures penetrate through periosteum to bone?

Answer 11

BV and N from periosteum penetrate to bone via Volkmann’s canal → connect with Haversian canal

Question 12

vascularity of cartilage

Answer 12

avascular

- chondrocytes receive nutrients & o2 via diffusion

Question 13

types of cartilage

Answer 13

hyaline: cover articular surfaces
fibrous: greatest # of collagen fibres → greatest tensile str (IV discs)
elastic: elastic and firm (external ear)

Question 14

step 1 bone formation

Answer 14

ossification centre appears in fibrous connective tissue membrane
- mesenchymal cells dev into osteoblasts

Question 15

step 2 bone formation

Answer 15

Bone matrix (osteoid) secreted within fibrous membrane
-  Oblasts → secrete osteoid → mineralised → trapped Oblasts become osteocytes

Question 16

step 3 bone formation

Answer 16

Woven bone and periosteum forms

• Osteoid accumulate b/w embryonic BV → form network of trabeculae
• Vascularised mesenchyme → condense external of network → becomes periosteum

Question 17

step 4 bone formation

Answer 17

Bone collar of compact bone forms + red marrow appears

• Trabeculae deep to periosteum thickens → forms woven bone collar later replaced with mature lamellar bone
• Spongy bone persist internally
• Vascular tissues → become red marrow

Question 18

bone growth

Answer 18

1) Formation of bone collar around hyaline
- With 1o ossification

2) Cavitation of hyaline cartilage (from 1o ossification
3) Invasion of periosteal bud (containing BV…) + spongy bone
4) Medullary cavity formed, 2o oss center appears in epiphysis (childhood)
5) Ossification of epiphyses

Question 19

bone remodelling with osteoclast and blast

Answer 19

• Oclast → enlarge diameter of medullary

- Oblast → Produce new bone around outside of bone

Question 20

fibrous articulations

Answer 20

• fibrous tissue
• no/little movement
• cranium sutures

Question 21

cartilaginous articulation

Answer 21

• hyaline
• slightly movable
• pubic symphysis/iv discs

Question 22

synovial articulation

Answer 22

• has joint capsule, synovial membrane, articular cartilage (hyaline), menisci, ligaments, bursae
• mobile

Question 23

bone and ageing

Answer 23

childhood + adolescence → osteogen > bone reabs (clast BD bones)

young adult → osteogen = bone reabs

Question 24

what 3 structures form the thin filament

Answer 24

actin + troponin + tropomyosin

Question 25

what form of energy is used for contraction

Answer 25

ATP - aerobic/anaerobic

muscle fibres breaking down creatine phosphate

Question 26

length of electrical impulse of cardiac muscle

Answer 26

longer than skeletal muscle

- does not run low on ATP and does not fatigue

Question 27

EC coupling of SM

Answer 27

Ca from outside cell (no sarcomere and SR)

- binds calmodulin → contraction

Question 28

2 types of SM

Answer 28

multiunit
- many independent single cell units → fine control of contraction (i.e. resp airway, arteries)

single unit

• large continuous sheet
• peristalsis
• i.e. GIT walls