Week 3- Embryonic period

Question 1

embryonic period

Answer 1

weeks 3-8
all body systems will structurally develop
none are fxnl except the card. sys
shape of the embryo changes (more human)

Question 2

three phases to embryonic devl

Answer 2

growth (cell division)
morphogenesis ( dev. of form and includes mass cell movements- make heart, lungs etc)
differentiation (maturation of physiological processes, give the cells specific functions)

Question 3

trilaminar embryo

Answer 3

dorsal, ectoderm
ventral endoderm
middle- mesoderm
made during gastrulation

Question 4

ectoderm

Answer 4

1. neuroectoderm which gives rise to all CNS (brain and spinal cord) and PNS (all autonomic NS)
2. Epidermal covering (all body and all their derivatives)

Question 5

neural plate

Answer 5

edges fold up and neural groove is formed, notochord underneath

Question 6

neuralation

Answer 6

the formation of the neural tube

Question 7

cranial neuropore and caudal neuropore

Answer 7

openings at ends of neural tube- close on specific days (cranial 25 and caudal 27/8)

Question 8

BMP4

Answer 8

is a ubiquitous neural protein, induces neural plate

Question 9

neural crest cells

Answer 9

super smart and moveable cells that make the connective tissue of the mesoderm, all of the PNS, line up the heart with its arteries, forms portions of your teeth, face, neck, dermis, adrenal medulla, schwann cells in PNS, melanocytes

Question 10

epidermal covering

Answer 10

makes pretty much all other tissue

epidermis, sweat glands, sebaceous glands, mammary etc

Question 11

axial mesoderm

Answer 11

makes notochord, precordal plate, caudal eminence (loss of primitive node)

Question 12

paraxial mesoderm

Answer 12

makes somitomeres in the head, precursor to somites.
in head: they make portions of neuroplate to form neuromeres (first 7 somitomeres)
In body: somitomeres-> somites, move occitpital to caudal, can determine age of the embryo
somites form sclerotome- ribs, vertebrae,base of skull
forms dermatomyotome

Question 13

sclerotome

Answer 13

vertebrea, ribs, base of skull

Question 14

dermatome

Answer 14

dermis of skin

Question 15

myotome

Answer 15

skeletal muscles of the body and limbs

Question 16

intermediate mesoderm

Answer 16

forms most organs, smooth muscles and epithelial linings, both urinary and genital systems

Question 17

embryonic folding

Answer 17

1. cephalocaudal folding- primitive streak and notochord establish a cephalocaudal axis, right side left side and dorsal ventral surface
   - rapid head and tail growth causes the embryo to curl toward the ventral surface (primarily the neural tube causes cephalic folding)

Question 18

lateral plate mesoderm

Answer 18

proliferation of LPM brings the ectoderm to the ventral surface, found in the body not the head
body splits into two arms:
1. somatic- to body wall (skin, muscle, cartilage, connective tissue)
2. splanchnic- goes around the 2* yolk sac (lines all endoderm-lined organs and all tissues of Card.Sys)

Question 19

lateral folding

Answer 19

endoderm becomes folded into a long narrow tube within the embryo
mesoderm continues to separate out ectoderm from endoderm
ectoderm and amniotic cavity completely encircle the embryo, ectoderm forming the outer covering of the embryo

Question 20

intraembryonic cavity

Answer 20

the cavity formed with the LPM closes off the ventral side
it forms the thoracic cavity
it forms the abdominal cavity
have to have somewhere to put our organs!!

Question 21

Extraembryonic mesoderm

Answer 21

mesodermal contribution to the chorion

partially for the maternal fetal circulation, because the fetus is getting bigger

Question 22

endoderm tube

Answer 22

pinched off yolk sac lined internally with endoderm
forms into the specific organs of the GI system
also makes portions of the pharynx and lungs, buds of liver, pancreas, gall bladder