MSK

Question 1

Intramembranous ossification?

Answer 1

Mesemchymal -> osteoblasts
Ossification centre forms, osteoblasts secrete osteoid
Osteoblasts trapped in osteoid, osteoid calcifies and hardens
for flat bones

Question 2

Endochondral ossification?

Answer 2

Newly formed osteoblasts form bone collar at diaphysis, cause matrix to calcify.
Periosteal bud (artery, vein, lymphatics and nerves) invades cavity.
Osteoclasts degrade cartilage matrix, diaphysis continues to enlarge.
Mesenchymal -> cartilage -> bone.
in long bones

Question 3

Interstitial growth?

Answer 3

Interstitial - long bones, increased length at physis.
Hyaline cartilage matrix formed at epiphyseal side, calcified and dies at diaphysial side and replaced by bone.

Question 4

Osteogenic cells?

Answer 4

Bone stem cells

Question 5

Osteoblasts?

Answer 5

Bone forming, secretes osteoid.

Question 6

Osteocyte?

Answer 6

Mature bone cell, osteoblast embedded in secretions, sense mechanical strain to direct osteoclast + blast activity.

Question 7

Osteoclasts?

Answer 7

Bone breaking, dissolve + resorb bone by phagocytosis. Derived from bone marrow.

Question 8

Organic vs inorganic bone matrix?

Answer 8

Organic - 40%, type 1 collagen and ground substance.
Inorganic - 60%, calcium hydroxyapatite, osteocalcium phosphate.

Question 9

Immature vs mature bone?

Answer 9

Immature - woven, weak.
Mature - lamellar structure, very strong.

Question 10

Cortical vs cancellous bone?

Answer 10

Cortical - compact, weightbaring.
Cancellous - spongy, honeycomb.

Question 11

Haversian canal?

Answer 11

Contains blood vessels, nerves and lymphatics. Osteons around it.

Question 12

Lacunae?

Answer 12

Small spaces that contain osteocytes.

Question 13

Volkmans canal?

Answer 13

Transverse perforating canal.

Question 14

Structure of bone from top to bottom?

Answer 14

Epiphysis
Physis
Metaphysis
Diaphysis

Question 15

Appositional growth?

Answer 15

Deposition of bone beneath periosteum to increase thickness.
Osteoblasts in endosteum build new concentric lamellar inward.
Osteoblasts in periosteum build new circumferential lamellae.

Question 16

3 types of joints?

Answer 16

Fibrous
Cartilaginous
Synovial

Question 17

Fibrous joints?

Answer 17

Sutures, immovable.

Question 18

Cartilaginous joints?

Answer 18

Semi-moveable, synchondroses (spine) and symphyses (pubic)

Question 19

Synovial joints?

Answer 19

Freely moving.
Plain, hinge, saddle, pivot, ball + socket.
Articular (outer) and synovial (inner).
synovial fluid reduces friction

Question 20

Hand osteoarthritis?

Answer 20

DIP, PIP joints. Followed by base of thumb.
Heberden’s nodes.

Question 21

Skeletal muscle small to big?

Answer 21

Myofilament, myofibril, myofibre, fascicles, muscle.

bone to muscle by tendon

Question 22

Muscles surrounded by?

Answer 22

Muscle fibre - endomysium
Fascicles - perimysium
Muscle - epimysium.

Question 23

Bands during contraction?

Answer 23

I band (actin, light band) - shorter
A band (myosin, dark band)- same length
H zone - narrows