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MCAT - Biology > MCAT Biology Ch5: Embryology Kap > Flashcards

MCAT Biology Ch5: Embryology Kap Flashcards

(96 cards)

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1
Q

cleavage

A

moving from fallopian tube => uterus to implanation => UNDERGOES RAPID MITOTIC CELL DIVISION (rapid)

first one creates an embryo

although several rounds of mitosis, total size of embryo remains unchanged during first few divisions

cells inc. two ratios: nuclear to cytoplasmic and SA to vol. => cells inc. area for gas nutrient diffusion relative to overall volume.

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2
Q

indeterminate

A

results in cells that can still develop into complete organisms.

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3
Q

determinate

A

cells whose fates are determined

differentiating into a certain type of cell

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4
Q

differentiating

A

results in CERTAIN type of cell

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5
Q

two types of cleavage

A

indeterminate or determinate

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6
Q

1st, 2nd, 3rd cleavages occurs

A

32, 60, 72 hours

at this point, 8 celled embryo completed to uterus

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7
Q

morula (cleavage)

A

several division occurs, the embryo becomes a solid mass of cells

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8
Q

blastulation (cleavage)

A

after morula

forms blastula

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9
Q

blastula (cleavage)

A

when implants outside of uterus => ectopic pregnancy (most in fallopian tube) => inviable => if embryo doesn’t spon. abort => tube may rupture => hemorrhaging

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10
Q

blastocoel (cleavage)

A

hollow, fluid-filled inner cavity of blastula

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11
Q

blastocyst (cleavage)

A

mammalian blastula

consists of two noteworthy cell groups: trophoblast and inner cell mass

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12
Q

two cell groups of blastocyst (cleavage)

A

trophoblast and inner cell mass

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13
Q

trophoblast (cleavage)

A

surround blastocoel and give rise to chorion, and later placenta

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14
Q

inner cell mass (cleavage)

A

protrudes into blastocoel and gives rise to organism itself

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15
Q

early developmental stages

A

cleavage, implantation, gastrulation, neurulation

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16
Q

implantation

A

blastocyst in uterine wall => blastocyst implants endometrium

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17
Q

endometrium (implanation)

A

prepared in anticipation, where blastocyst implants here

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18
Q

progesterone (implanation)

A

steroid hormone promote proliferation of (endometrial) mucosal layer to help embryo implact

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19
Q

key step of implanation

A

embryonic cells secrete enzymes that burrow into endometrial lining to allow for implantation => form connection to maternal circulation for nutrient and gas exchange

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20
Q

implantaton like tree

A

seed (embryo) into ground (endometrium) => make sure soil is fertile (progestrone to endometrium)

shovel to plant seed in ground (proteolytic enzyme allow embryo to settle in uterine wall)

tree generate roots (placenta) => gas and nutrient exchange w/ soil (endometrium)

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21
Q

gastrulation

A

generation of 3 distinct cell layers

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22
Q

gastrulation in sea urchins

A

begins w/ small invagination in blastula => cells continue moving toward invagination => elimination of blastocoel => gastrula

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23
Q

gastrula (gastrulation )

A

two-layered cup form after elimination of blastcoel

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24
Q

endoderm (gastrulation)

A

inner cell layer

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25
ectoderm (gastrulation )
outer cell layer cells migrate over the neural tube and crests to cover rudimentary nervous system
26
archenteron (gastrulation )
cavity created by deep invagination later develops into gut
27
blastophore (gastrulation )
opening of archenteron
28
deuterostomes (gastrulation )
in humans, blastopore develops into anus
29
protostomes (gastrulation )
blastopore dvelops into the mouth
30
mesoderm (gastrulation)
eventually some cells also migrate into area between ectoderm and endoderm
31
parts of ectoderm (gastrulation )
attract o derm
32
parts of mesoderm (gastrulation)
"means" o derm, we get from place to place in world
33
part of endoderm (gastrulation)
"endernal" orgams long tubes running from mouth to anus (digestive tract), organs attached to it (accessory organs of digestion) gives rise to the lungs
34
cleavage
single cell zygote => several mitosis occur (total size of embryo same) => several division becomes morula => blastulation
35
embryonic stem cells
derived from portion of very early stage emybryo => entire body (retain pluripotent ability to form any cell type)
36
cell fate
less than a week after human egg fertilized => developing embryo (blastocyst which only an outer cell mass, in preg. becomes placenta, and inner cell mass, which becomes fetus) => in womb, cells multiply
37
making embryonic cells
create by remove inner cell mass from blastocyst ICM on plate containing feeder cells => attaches => few days, new cells grow out of ICM => form colonies
38
two criterias of ES cells
1. display markers 2. undergo several generations of cell division, or passages, => show that they constitute a stable, or immortalized, cell line
39
selective transciption of Somatic cells DNA (gastrulation)
of the genome (only genes for eye are tunred on in the eye. often related to concept of induction => ability of certain group of cells to influence the fate of other nearby =>
40
inducers (gastrulation)
selective transcription process mediated by these chem, substances passed from organizing cells to responsive cells
41
neurlation
once three germ layers => DEVELOPMENT OF NERVOUS SYSTEMS CAN BEGIN
42
nervous system derived from neurulation
cells migrate inward => notochord => induce group of ectodermal cells to slide inward to form neural folds => surround neural grove => grow together one another => neural tube => CNS
43
notochord
rod of mesodermal cells, forms along the long axis of organism induce group of ectodermal cells to slide inward to form neural folds
44
neural folds
induce group of ectodermal cells to slide inward to form surround neural groove
45
neural tube
neural folds grow toward one another until they fuse into this
46
neural crest cells
tip of each neural fold cells migrate outward to form PNS (sensory ganglia, autonomic ganglia, adrenal medulla, Schwann cells
47
fetal respiration
nutrient and gas exchange w/ maternal ciruclation necessary part of fetal development
48
two structures of fetal development
placenta and umbilical cord
49
placenta
primarily formed from chorion organ where nutrient, gas, and waste exchanges occur; simplest way is through diffusion in fetus crucial that no mixing of maternal and fetal blood (may have diff. bloods) => diffusion higher P(oxygen) in maternal blood than in fetal blood waste materials and CO2 move in opposite direction endocrine organ, since produces progesterone, estrogen, and human chorionic gonadotropin, all essential for maintaining pregnancy (266 days)
50
chorion
placenta primarly formed from an extra-embryonic membrane develops from trophoblast cells outermost embryonic layer, completely surrounds the other membrane, providing added level of protection
51
human umbilical cord
and vessels provide attachment to chorion and nutrition for fetus surround by jellylike matrix initial connection of fetus to mother
52
three extra embryonic membranes of fetal respiration
allantois, amnion, yolk sac
53
allantois
surround by amnion
54
amnion
thin, tough membrane filled w/ amniotic fluid
55
amniotic fluid
shock absorber during pregnancy and labor
56
yolk sac
site of blood vessel development
57
chorionic villi
eventually grow into placenta support maternal fetal gas exchange
58
amniocentesis
aspirating amniotic fluid by inserting a thin needle into amniotic sac
59
amniotic fluid
contains fetal cells can be examined for chromosomal abnormalities and sex determination can result in genetic aberrations like Down Syndrome
60
fetal hemoglobin Hb-F
fetal blood cells equipped w/ this, which exhibit greater affinity for oxygen than does maternal (adult) hemoglobin, known as Hb-A
61
Hb-A
maternal (adult) hemoglbin
62
placenta barrier
immune protection foreign particles and bacteria too large to cross by diffusion, however not the case for virus, alcohol, toxins
63
two important organs that are underdeveloped in fetus and rely on placenta
lungs and liver
64
fetus lungs
not able to oxygenate circulating blood are suspended in aq. amniotic fluid => no air to take in oxygen comes from maternal circulation => diffuse through placenta vessel
65
two fetal shunts keep blood away from LUNGS by rerouting blood w/in heart
foramen ovule and ductus arteriosus
66
foramen ovule
connects right and left atria blood entering superior vena cava => right atrium => left atrium => out of aorta into systemic circulation pressure differential: -pressure higher in right atrium since will spon. down pressure gradient gradient reverse in adults => forman ovale shut after birth
67
ductus arteriosus
present to shunt leftover blood from pulmonary artery to aorta works like forman ovale => pressure right fetal heart is higher that that of the left patent ductus arteriosus (PDA) => stays open after birth -direction of blood flow through PDA will be determined by relative resistance of pulmonary and systemic circulation => if cont. => neonate will turn blue since deoxygenate venous blood bypasses lung and mixes w/ oxygenated blood being pump to body through aorta
68
fetal liver
underdeveloped, can't fully able to carry out adult taks in utero since placenta capable of pitching during gestation, blood returning from placenta via umbilical vein is rerouted to inferior vena cava via this even though needs a lot of O2, it prevents from stealing oxygen from designated from rest of the body => liver has own reserves from arteries leaving the heart.
69
umbilical arteries
carry blood away from fetus carry deoxygenated blood
70
umbilical vein
blood toward the fetus carry oxygenated blood
71
human pregnancy
266 days divided into 3 trimesters
72
gestation rule
larger the animal, longer the gestational period, and fewer the offspring
73
first trimester of pregnancy
end of third month: | 1. fetus abou 9 cm long
74
first trimester of pregnancy (first week)
major organs develop 1. heart beats to beat approx. 22 days 2. eyes, gonads, limbs, and liver start to form
75
first trimester of pregnancy (five weeks)
1. embryo is 10 mm length
76
first trimester of pregnancy (six week:)
1. 15 mm length
77
first trimester of pregnancy (seventh week)
1. by this time, cartilaginous skeleton begins to harden into bone
78
first trimester of pregnancy (eight week)
1. most organs have formed 2. brain fully developed 3. embryo = fetus
79
first trimester of pregnancy (3rd month)
fetus about 9 cm long
80
second trimester of pregnancy
fetus undergoes amount of growth begins to move around in amniotic fluid toes and fingers elongate end of sixth month - fetus measures 30 to 36 cm long
81
third trimester of pregnancy
7th and 8th month = cont. rapid growth and further brain development 9th month - antibodies transported by highly selective active transport from mom to fetus for protection against foreign matter, in prep outside of womb growth rate slows and fetus becomes less active since less room to move about
82
vagina childbirth
by rhythmic contractions of uterine smooth muscle, coordinated by prostaglandins and peptide hormone oxytocin
83
3 basic phases to childbirth
1. cervix thin out and amniotic sac ruptures (water breaking) 2. strong uterine contraction => birth of fetus 3. placenta and umb. cord are expelled (afterbirth)
84
monozygotic twins
identical genomes because both originate from indeterminately cleaved cells of same embryo
85
embroyo w/ blasted out cavity
this is blastula
86
adrenal cortex
derived from mesoderm
87
adrenal medulla
derived from ectoderm (since contains some nervous tissue)
88
spinal bifida
failture of neutral tube to close
89
zygote
undergoes several rapid divisions -> determinate cleavage
90
indeterminate cleavage
generation of identical twins
91
gasturalation
neuralation occurs during this
92
fetal respiration
occurs in placenta and not in developing lungs
93
ductus venosus
since placenta capable of pitching during gestation, blood returning from placenta via umbilical vein is rerouted to inferior vena cava via this even though needs a lot of O2, it prevents from stealing oxygen from designated from rest of the body => liver has own reserves from arteries leaving the heart.
94
ductus venosus
fetal shunt of liver
95
fetal circulation contains 3 shunts
ductus venosus, foramen ovale, ductus arteriosus
96
gestation
consists of three trimesters of 3 months each

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