Embryology of Brain

Question 1

What is a blastocyst?

Answer 1

group of cells with cyst in the middle

Question 2

Bilaminar Disk

Answer 2

Outer and Inner cell mass, undifferentiated cells or embryonic stem cells

Question 3

What is an embryonic stem cell?

Answer 3

cells that can become any tissue

Question 4

What is main difference in adult stem cell?

Answer 4

organ specific differentiation

ex.) liver cell likely to become a liver cell

Question 5

Ectodermal Stem cells

Answer 5

makes skin or nervous system cells, depending on hormones

Question 6

Epithelial stem cells

Answer 6

skin cells

Question 7

Neural stem cells

Answer 7

neuroblasts become neurons

spongioblasts become glia

Question 8

When is the trilaminar disk created?

Answer 8

two weeks post fertilization

Question 9

what is the ectoderm?

Answer 9

skin, brain cells and some glands

Question 10

What is endoderm?

Answer 10

becomes inner tubes of gut and vessels

Question 11

What is mesoderm?

Answer 11

connective tissue development and form somites

Question 12

What is the notochord?

Answer 12

architect of embryological development

releasing hormones in embryo at right time (introduction of differentiation)

Question 13

What is the neural plate?

Answer 13

thickening of neural ectoderm

Question 14

What does the neural tube become?

Answer 14

the CNS

Question 15

What does neural crest become?

Answer 15

the PNS (ganglia and nerves), dragged into final location by somites

Question 16

When does neuropores of the neural tube begin to close?

Answer 16

week 4, anterior before posterior

Question 17

What are the somites formed from?

Answer 17

mesoderm

Question 18

What is a somite?

Answer 18

special area in mesoderm which can become vertebrae, muscles, cartilage, tendon and skin

Question 19

What is the alar plate?

Answer 19

dorsal portion of neural tube in cross section, sensory portion

Question 20

What is the basal plate?

Answer 20

ventral portion of neural tube, motor portion

Question 21

What sulcus separates alar and basal plate?

Answer 21

sulcus limitans

Question 22

What are the 3 primary vesicles of embryo?

Answer 22

pro-, mes- and rhombencephalon

Question 23

What are the secondary vesicles of embryo?

Answer 23

1. Pro- becomes Tel- and Diencephalon

2. rhom- becomes Met- and myelencephalon

Question 24

What is the cephalic flexure?

Answer 24

between prosencephalon and mesencephalon

responsible for change of axis

Question 25

What is pontine flexure?

Answer 25

between met and mylen- for cerebellum

happens last

Question 26

What is cervical flexure?

Answer 26

transition to spinal cord

Question 27

What does telencephelon become?

Answer 27

lateral ventricles 1-2 and cerebral hemispheres

Question 28

What does diencephalon become?

Answer 28

third ventricle at its center and thalamus, retina and hypothalamus

Question 29

What does mesencephalon become?

Answer 29

cerebral aqueduct and midbrain

Question 30

What does metencephalon become?

Answer 30

fourth ventricle and pons and cerebellum

Question 31

What does mylencephalon become?

Answer 31

fourth ventricle and central canal and medulla

Question 32

Time points for primary neural defects?

Answer 32

formation of neural tube- 4 weeks

formation of encephalon- 6 weeks

Question 33

Spina Bifida

Answer 33

failure of closing of posterior neuropore before sinking into mesoderm

Question 34

Anencephaly

Answer 34

failure of closing of anterior neuropore before sinking into mesoderm

Question 35

What are causes of spina bifida?

Answer 35

drugs, nutrition, toxins etc.

Question 36

What is the sonic hedgehog hormone?

Answer 36

binds with receptors and alters gene expression

promotes normal development of ectoderm, mesoderm and endoderm

Question 37

What happens with abnormal SHH?

Answer 37

holoprosencephaly- single hemisphere

cerebellar tumors

basal cell carcinoma- skin cancer