embryology

Question 1

what are the two reasons for nervous system organization?

Answer 1

functional and developmental

Question 2

characteristics specific to vertebrates

Answer 2

• bilaterally symmetrical
• have a head and tail
• bodies are segmented
• hollow, dorsal neural tube

Question 3

vertebrates at bilaterally symmetrical

Answer 3

• structures are situated so that they are paired and a mirrored image exists on the opposite side
• this is a developmental characteristic that is seen in some intervertebrates as well

Question 4

all vertebrates have a head and tail

Answer 4

• a zygote is polarized very early on and all systems are set up to reflect this
• alimentary canal starts at the head and ends at the tail
• the senses are all clustered around the start of the digestive canal near where we take in food
• consequently, we get a “swelling” at the front or beginning because we need to deal with all the stimuli there

Question 5

all vertebrates bodies are segmented

Answer 5

• the body is constructed of repetition of segments
• these are situated perpendicular along a long axis
• each segment developmentally produces accompanying organs and systems

Question 6

all vertebrates have a hollow, dorsal neural tube

Answer 6

intervertebrates have a solid rope-like nervous cord

Question 7

mitosis starts within ____________

Answer 7

24 hours

Question 8

in 3-4 days a sphere of cells called the ________ is formed

Answer 8

morula

Question 9

• morula becomes hollow sphere of cells called blastocyst

- enters uterine cavity and implants in all at about 6 day post fertilization

Answer 9

week 1

Question 10

one part of hollow ball starts to fold inward, creating 2 layers or bilaminar embryo

Answer 10

week 2

Question 11

• becoms trilaminar (3 layers called germ layers)

- once layers start to form, called a gastrula

Answer 11

week 3

Question 12

inducing power

Answer 12

notochord

Question 13

neural plate is seen _________

Answer 13

18-19 day PC

Question 14

cell proliferation produces an _____

Answer 14

inward folding

Question 15

inward folding starts ______

Answer 15

21-22 days PC

Question 16

when the inward folding seals it creates the _____

Answer 16

neural cord

Question 17

inward folding sealing happens ____

Answer 17

22-26 days PC

Question 18

what do the growths on both sides of the neural tube become?

Answer 18

neural crest

Question 19

the neural crest eventually becomes the ____

Answer 19

PNS

Question 20

the spot on the neural tube where the closure begins eventually becomes the _____

Answer 20

midbrain

Question 21

anterior end of neural tube

Answer 21

anterior neuropore

Question 22

what happens if the anterior neuropore does not close correctly?

Answer 22

the brain wont develop

Question 23

closure of the anterior neuropore happens ________

Answer 23

24-25 days PC

Question 24

anterior end closes ____ than the opposite end

Answer 24

sooner

Question 25

after closure of the anterior neuropore a bulge of cells form, this bulge eventually becomes the

Answer 25

brain

Question 26

the end opposite to the anterior neuropore is the

Answer 26

posterior neuropore

Question 27

if the posterior neuropore doesn't close correctly

Answer 27

spina bifida

Question 28

closure of the posterior neuropore happens __________

Answer 28

around day 26 PC

Question 29

what do the bulges eventually grow and create? when does this happen?

Answer 29

they create the three vesicle system (primary vesicles) happens by the end of week 4

Question 30

what are the names of the three vesicles?

Answer 30

- prosencephalon - mesencephalon - rhombencephalon

Question 31

what do the three vesicles develop into?

Answer 31

the brain

Question 32

when do the three vesicles turn into five vesicles?

Answer 32

week 5

Question 33

- forebrain - grows fastest - eventually separates into the telencephalon and diencephalon

Answer 33

prosencephalon

Question 34

the midbrain

Answer 34

mesencephalon

Question 35

- hindbrain | - develops into two lobes

Answer 35

rhombencephalon

Question 36

develops into cerebellum and pons

Answer 36

metencephalon

Question 37

develops into medulla

Answer 37

myelencephalon

Question 38

when the two hemispheres of the telencephalon start to pinch what is that the starting formation of?

Answer 38

the corpus callosum

Question 39

- inside remains hollow but begins to fill with CSF

Answer 39

neural tube

Question 40

develop into - most of PNS - sensory receptors in muscles - pigment in skin cells and iris - adrenal medulla

Answer 40

neural crest cells

Question 41

- where epinephrine is produced | - on top of kidneys

Answer 41

adrenal medulla

Question 42

a peptide which causes cell proliferation and development

Answer 42

NGF

Question 43

- area closest to the ventricle - where cells divide - cells are forced outward after genesis forming concentric rings

Answer 43

germinal zone

Question 44

- second connection rings - cells differentiate in morphology - gray matter forms

Answer 44

mantle

Question 45

- outer most layer - myelin produced - produces glial cells

Answer 45

marginal

Question 46

the elongation of circles form the medial horizontal crease called the

Answer 46

sulcus limitans of his

Question 47

- dorsal portion - sensory afferent portion of spinal cord - contains neurons that carry info from PNS to brain

Answer 47

alar

Question 48

- ventral portion - motor efferent - motor neurons from spinal cord to muscles

Answer 48

basal

Question 49

majority of the brain comes from the ______

Answer 49

alar

Question 50

what are the development of head and face induced by

Answer 50

neural crest cells

Question 51

what is thickening called

Answer 51

placodes

Question 52

- occur in the head - each needs neural crest - own set of rules - sends sensory receptors directly to brain - only vertebrates have them

Answer 52

placodes