Lecture 1

Question 1

Axial Skeleton Endochondral Derivatives

Answer 1

• Vertebral Column
• Ribs
• Sternum

Question 2

Appendicular Skeleton Endochondral derivatives

Answer 2

• Limbs

Question 3

Mixed endochondral and intramembranous derivatives

Answer 3

• Skull

- Clavicles

Question 4

Endochondral derivatives in Skull

Answer 4

• Cranial base and sensory capsules

- Ear ossicles and laryngeal cartilage

Question 5

Intramembranous derivatives of skull

Answer 5

• Cranial Vault

- Face

Question 6

Intramembranous Bone Growth

Answer 6

Spreading of bone spicules

Question 7

“Soft Spot”

Answer 7

Anterior fontanelle

Question 8

Skull stops growing at what age?

Answer 8

5-7 years

Question 9

Endochondral Bone Formation

Answer 9

• Mesenchyme condenses
• At primary center, Chondrocytes differentiate and form cartilage
• Chondrocytes mineralize
• Osteoblasts follow nutrient artery and bind to mineralized matrix
• Secondary centers start ongoing growth

Question 10

When does the diaphyses ossify?

Answer 10

By birth

Question 11

Formation of interverterbral discs

Answer 11

Sclerotomes and notochord

Question 12

8 cervical nerves and 7 cervical vertebrae

Answer 12

Lose half a sclerotome at skull base and another at T1

Question 13

Myoblasts

Answer 13

• Muscle precursors

- develop from mesoderm

Question 14

Splanchnic mesoderm

Answer 14

Gives rise to smooth muscle

Question 15

Muscle precursors rising from ectoderm

Answer 15

• Iris
• Mammary Glands
• Sweat Glands

Question 16

Paraxial Mesoderm

Answer 16

Gives rise to skeletal muscle

Question 17

Somitomeres

Answer 17

Give rise to muscles in the head

Question 18

Epaxial muscles

Answer 18

Form extensors of the neck and trunk

Question 19

Hypaxial muscles

Answer 19

Form the rest of axial and limb muscles

Question 20

Cervical Hypaxial musculature

Answer 20

• Neck flexors

- Hyoid muscles

Question 21

Thoracic Hypaxial musculature

Answer 21

Flex and bend trunk

Question 22

Lumbar Hypaxial musculature

Answer 22

Hip Flexor

Question 23

Sacrococcygeal Hypaxial musculature

Answer 23

• Pelvic diaphragm

- Striated muscle of perineum

Question 24

Limps Hypaxial musculature

Answer 24

Flexors and extensors

Question 25

FGF-10

Answer 25

- Signal molecule from lateral plate mesoderm | - Begins limb formation at Apical Ectodermal Ridge

Question 26

Segment Separation

Answer 26

- Constrictions at wrist and elbow | - Division of Apical ectodermal ridge and apoptosis in between digits

Question 27

First Wave of innervation

Answer 27

Motor neurons

Question 28

Second wave of innervation

Answer 28

Sensory neurons (Schwann cells)

Question 29

Dorsal Primary Ramus

Answer 29

Only epaxial and skin around back

Question 30

Upper limb rotation

Answer 30

90 degree lateral

Question 31

Lower limb rotation

Answer 31

90 degree medial

Question 32

Somatic lateral plate mesoderm

Answer 32

Bone and Vessels

Question 33

Myotome

Answer 33

Muscle

Question 34

Formation of melanocytes

Answer 34

Neural crest cells

Question 35

Formation of nerves

Answer 35

- Motor - Neural tube | - Sensory - Neural crest