Chapter 8

Question 1

Pre embryonic stage (conception to day 14)

Answer 1

Fertilization of ovum in the uterine tube
Fertilized ovum begins cell division
Solid sphere of cells forms → cavity opens up in the sphere
outer layer of sphere becomes fetal contribution to placenta
Inner cell mass becomes embryo
Implantation → inner cell mass develops into embryonic disk
Ectoderm, endoderm, mesoderm forms

Question 2

Embryonic stage ( day 15 → end of 8th week)

Answer 2

Organs begin to form
Formation of nervous system begins

Question 3

Ectoderm develops into…

Answer 3

Sensory organs, epidermis, and nervous system

Question 4

Mesoderm develops into…

Answer 4

Dermis, muscles, skeleton, excretory and circulatory systems

Question 5

Endoderm develops into…

Answer 5

Gut, liver, pancreas, respiratory system

Question 6

Fetal stage (end of 8th week → to birth)

Answer 6

Nervous system develops fully
Myelination begins

Question 7

Nervous system phases

Answer 7

1) tissue that will become NS comes together to form a tube running along the back of the embryo
2) when the tube closes, brain formation begins

Question 8

Neural plate

Answer 8

Longitudinal thickening of the ectoderm
Forms on the surface of the embryo, from head to tail region

Question 9

Neural groove

Answer 9

Edges of neural plate fold

Question 10

Neural tube

Answer 10

When folds of neural groove touch (day 21)
Closes first in future cervical spine region

Question 11

Neuropores

Answer 11

When neural groove zips closed, rostraly and causally openings are left

Question 12

Neural crest

Answer 12

Cells adjacent to neural tube separate from tube and remaining ectoderm

Question 13

Soma

Answer 13

Cell body of a neuron

Question 14

Somites

Answer 14

Spherical cell clusters of mesoderm formed parallel to the neural tube

Question 15

Sclerotome

Answer 15

Anteromedial part of somite
Becomes vertebrae and skull

Question 16

Myotome

Answer 16

posteromedial part of somite
Becomes skeletal muscle
AND
After embryonic stage, a group of muscles innervated by a segmental spinal nerve

Question 17

Dermatome

Answer 17

Lateral part of somite
Becomes dermis
AND
after embryonic stage, the dermis innervated by a single spinal nerve

Question 18

Motor plate

Answer 18

Ventral section of neural tube

Question 19

Association plate

Answer 19

Dorsal section of neural tube

Question 20

Ventral horn

Answer 20

Gray matter derived from the motor plate

Question 21

Dorsal horn

Answer 21

Gray matter derived from association plate

Question 22

Primary sensory neurons

Answer 22

Peripheral sensory neurons
Convey information from sensory receptors to association plate

Question 23

Cauda Equina

Answer 23

Collection of lumbosacral nerve roots that extend inferior the the end of the spinal cord (resembles horses tail)

Question 24

Filum terminale

Answer 24

Continuation of the Dura, pia, and glia connecting to the end of the spinal cord with the coccyx

Question 25

Brain formation

Answer 25

Begins day 28

Question 26

Hindbrain

Answer 26

Becomes medulla, pons, and cerebellum

Question 27

Posterior forebrain

Answer 27

Becomes diencephalon

Question 28

Anterior forebrain

Answer 28

Becomes telencephalon