Embryology 3

2. located dorsal to 2nd pharyngeal cleft; 28 days
5. forms from tissues of 1st and 2nd pharyngeal arches; 5th week
7. hollow fluid-filled epithelial ball formed from otic placode
10. ___ of first pharyngeal pouch will line middle ear cavity and eustachian tube
13. mass of mesodermal tissue trapped dorsal to TM contains cartilage masses that will produce the ___
15. hillocks #4,5 that form pinna
16. each pharyngeal arch is a bar of ___ tissue separated from the next by pharyngeal cleft
17. failure of fusion of dorsal part of neural tube in spinal column
18. 2nd pharyngeal arch
19. 25 brain and spinal cord have full complement of neurons
20. lateral surface of 1st pharyngeal groove gives rise to ___ and cells in this area multiply to produce meatal plug
21. hillock #1 that forms pinna
22. pharyngeal pouch ___ will form middle ear cavity and medial surface of TM
23. small brain and bony skull as well as small face
24. present during development but disappear later on

1. on either side of neural plate, superficial ectodermal thickenings appear
3. no brain tissue above brainstem
4. series of bands of tissue lying under early brain that develop into structures of head and neck
6. 1st pharyngeal arch
8. error in separation of cerebrum into 2 hemispheres
9. caudal displacement of cerebellar tissue through foramen magnum
11. olfactory, visual, and auditory sensory organs as well as nerves that correspond to these systems form from regions of thickened ectoderm at anterior end of embryo
12. hillock #6 that forms pinna
14. ___groove ectoderm develops into EAC and lateral layer of TM
20. hillocks #2,3 that form pinna