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bio II, spring > development > Flashcards

development Flashcards

1
Q

defining feature gastrulation

A

The primary germ layers (endoderm, mesoderm, and ectoderm) are formed and organized in their proper locations during gastrulation. gastrulation is when you see hensen’s node, invagination, etc

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2
Q

neural crest formation & migration

A

forms along the neural tube; blocks of cells (somites) migrate from the crest and signal nearby cells to begin developing into other parts of the body. secondary induction

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3
Q

describe how and when implantation of the embryo into the uterine wall occurs

A

1 week in, embryo signals its trophoblasts to turn into ST’s, and then uses syctiotrophoblasts to burrow into endometrial lining, fusing with it

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4
Q

some examples of deuterosomes

A

vertebrates + echinoderms (sea urchins)

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5
Q

describe how the zona pellucida reacts when a sperm enters the egg

A

cortical granules prompt it to harden and separate out , creating a firm barrier around the egg

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6
Q

how does birth control work?

A

maintain Estrogen + Progesterone levels , inhibits release of these hormones, so no new ovulation happens

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7
Q

describe the secretory pathway that triggers ovulation, menstruation, etc

A

hypothalamus secretes GnRH to the pituitary gland. P gland then produces LSH, Surge in LH causes ovulation. ovulation and successive events then release estrogen + progesterone back to the pituitary gland in a feedback loop

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8
Q

in what stage (n/2n ) are germ cells?

A

2n

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9
Q

capacitation

A

making sperm more competent to fertilize eggs- do this in IVF by doing a saline wash of fallopian tubes then dumping that into the petri dish

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10
Q

discuss some potential neural tube defects and what causes them

A

neural tube can fail to close at top, middle, or bottom end. an unclosed tube at the top can lead to a child forming wihtout a brain- this pregnancy would terminate. if in lower end, kid could be born with spina bifita .

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11
Q

what happens differently to the corpus luteum if the egg is fertilized?

A

HCG is secreted by the chorion (outer layer of developing embryo) which rescues the corpus luteum. you want the CL around as it secretes estrogen + progesterone, which help to inhibit dilation + contractions

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12
Q

describe the structure of a sperm and what each compartment houses

A

the top houses the ‘acrosomal vesicle’ which contains lysosomes to digest the outer membrane of the egg. the midsection contains the mitochondria. the tail, the flagella, contains microtubules in a 9+2 arrangement

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13
Q

describe features in 3rd trimester

A

3rd trimester, months 7-9: Brain development. Pruning (elliminate unwanted connections) Requires lots of nutrients Most growth happens in first year of life so head wont be too big to come out!

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14
Q

Corona radiata

A

radiating crown of cells around the mature egg. Instead of jelly layer like sea urchins have. its actually a bunch of attached follicle cells

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15
Q

neurulation: description and key features

A

ectoderm (on top) rolls into the neural tube, which is essential to forming the chordate dorsal hollow nerve chord; example of primary induction features: notochord . ectoderm -> neural tube. head/tail regions, gut opens into anus and mouth ends

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16
Q

what causes menstruation?

A

fall off of progesterone

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17
Q

some examples of protosomes

A

worms + mollusks

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18
Q

when would meiosis 2 be completed in oogenesis?

A

when ovum meets sperm in fertilization event

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19
Q

describe what you would have at beginning and end of cleavage

A

start: zona pellucida, blastomere, polar bodies. fertilized egg, not much else. end: inner cell mass, trophoblasts surrounding it, and blastocyst cavity

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20
Q

describe how estrogen and progesterone cycle during the 28 day period

A

estrogen (in form of estradiol) spikes at 14 days, during ovulation, and then rises again around 26 days. progesterone spikes at 21 days, falls the rest of the time

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21
Q

describe the secretory pathway occurring during monthly menstruation

A

Hypothalamus : release GnRH to pituitary gland Pituary: receives GnRH, triggered to release reproduction hormones FSH, LH. (Follicle stimulating hormone + leuteinizing hormone) Feedback mechanisms; high FSH + LH inhbit hypothalamus from producing more stuff.

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22
Q

after how many weeks would you expect to see hensen’s node?

A

2

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23
Q

cleavage/blastulation: description and defining features

A

process of going from __ to blastula. key features are hollow cavity inside called blastocoel. holoblastic + radial in deuterosomes.

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24
Q

describe how marsupials reproduce and what is unique about them

A

embryonic diapause: ability to freeze fertilized egg while they nurse a newborn + toddler. 3 different stages of life all in one mom. very short gestation and long lactation period, differentiated based on age of child.

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25
describe the functions of estrogen and progesterone
estrogen prepares the wall of the uterus through actions like cell division, vascularization progesterone maintains the uterine cell wall thus, when progesterone falls, the wall comes off
26
what do you call a fertilized, single celled , DIPLOID egg?
zygote
27
discuss the 5 stages of development
1) cleavage: 10 rounds - embryo -\> blastula 2) infolding: blastula -\> gastrula 3) neurulation: forms dorsal hollow nerve cord 4) neural crest cell formation 5) organogenesis: forms fetus (9-12 weeks)
28
when does the zona pellucida degenerate?
when the embryo becomes a mature blastula and needs to interact with the uterine wall- allows trophoblasts to burrow. 1 week out.
29
describe what gastrulation does and how you know you are seeing it
turns a bilaminar emrbyo into a trilaminar embryo complete with an ectodern, mesoderm and endoderm. You will see folding of the embryonic disc and formation of extraembryonic spaces
30
describe ovarian cycle vs estrous cycle and then monoestrous or polyestrous
humans use ovarian cycle- once per month, longer cycle, and mestruation. most other mammals use 'estrous cycle' where they do not bleed, Involves shorter luteal cycle . Less endometrial buildup. and a period of heat. monoestrous: cycle occurs 1x per year (deer) polyestrous: cycle occurs multiple times a year (cats)
31
gastrulation: description and key features
movement of cells into cavity to create three primary germ cell layers (and visible primitive streak), which later give rise to the specific tissue types. The endoderm will lead to the gut and the gut-related organs. The mesoderm will lead to muscle, notochord, skeleton, etc. The ectoderm will lead to the skin and neural tube (and therefore brain, spinal chord, and nerves.) key features: 3 primary germ layers, invagination to form archenteron, and dissapearing blastocoel, and notochord
32
what is the antrum?
the cavity within a mature oocyte that is about to be ovulated. causes it to bulge out of the wall of uterus
33
describe how lactation begins and how it is also a positive feedback loop
Once baby delivered, progesterone stops inhibiting lactation. Mom releases prolactin. When baby suckles, nerve endings stimulate hypothalamus -\> release oxytocin -\> oxy interacts with smooth muscle surrounding milk ducts to squeeze out milk. Pos feedback loop- as long as baby continues 2 suckle, milk keeps coming. Material accumulates in breast that has nutrients + antibodies. That’s what baby gets at first. (colustrum) After a couple of days , milk comes in.
34
somites
A somite is a division of the body of an animal or embryo. Somites are bilaterally paired blocks of paraxial mesoderm that form along the head-to-tail axis of the developing embryo in segmented animals.
35
what is the function of the chorion?
Emrbyo's connected to mom via body stalk, which becomes umbilicial cord at one month. chorion connects baby to mom's blood supply, is the precursor to the placenta
36
where does gastrulation happen
fallopian tube
37
what are some of the different ways you could have twins?
fraternal twins: 2 eggs both implant, each embryo develops normally identical twins: one fertilized egg splits. can happen early on or very late (blastula) stage
38
protosomes vs deuterosomes: big difference?
in protosomes, the first opening to develop is the mouth. in deuterosomes, first anus, then mouth
39
key events in cleavage
radial, holoblastic (deuterosomes)
40
describe the process of oogenesis from birth
primary oocytes arrested in prophase 1 until puberty; 20 follicles per month mature into primary follicles, and some into secondary follicles. 1-2 secondary follicles becomes a vesicular follicle . primary oocyte ovulates, completes first meiotic division, becomes secondary oocyte. 23, n. if fertilized, completes secondary meitotic division, becomes ovum, otherwise, degenerates, secreted out
41
describe the Coelom
body cavity that forms in mesodermal layer. forms differently for protosomes and deuterosomes.
42
describe fetus features in 2nd trimester
2nd trimester, months 4-6: 7-8 inches long. Kicking 4-5 months. Body with lanugo-fetal hair; very thin pale layer of hair. Heartbeat detectable with stethoscope. 180 bpm, extrmeley rapid
43
what is the decidua and how does the mom's body ensure that there is enough surface area for gas exchange, nutrient exchange etc?
desidua = maternal layers of placenta ”blood islands” : allows maternal blood to be right next to the villi, to allow better diffusion.mom’s blood has broken down the layers around the blood vessel- removes its endoderm, connective tissue, and blood spills into these little blood islands
44
around how many weeks does gastrulation occur at?
3
45
name 3 features you'd see in blastula
blastocoel/blastocyst cavity, trophoblasts, inner cell mass
46
describe external fertilization, such as that seen in echinoderms
sperm meets egg- acrosomal enzymes begin digesting outer layer. when acrosome breaks open, actin microfilament nose pops out, pushes out bindin molecules, which recognize only bindin receptors of their species. once fusion occurs , sperm has gotten thru vitelline coat, vitellin membrane pops up to stop other sperm from getting thru, and fusion/dna exchange occur
47
what do egg yolks have surrounding them?
vitelline membrane
48
describe the differences in fetal vs newborn circulation
fetus does not have working lungs; cannot oxygenate its own blood. all the oxygen has to come from the placenta. goes to umbilicus vein, right side of heart, left side of heart, to body. has 'foramen ovale' (hole) between chambers of its heart, to allow blood to cross thru atria also has 'ductus arteriosus' : connects pulmonaries to the aorta. newborn: lungs inflate, get blood from right side of heart directly to lungs. blood goes directly to heart, out pulmonary artery, to lungs, foramen ovale closes up
49
name some features you might see in gastrulation
archenteron, blastopore, formation of early mouth/anus
50
discuss indeterminate development and how that plays out for protosomes vs deuterosomes
indeterminate development means that cells are not yet fixed- like a stem cell, can still develop into something else. because of this, you can take 1 cell out of a deuterosome embryo of 8 cells, and a normal embryo will still develop. for protosomes, if you remove a cell, development stops
51
sustentacular cells
support development of sperm. accessory cell
52
describe what u might see in neurulation
Neurulation in vertebrates results in the formation of the neural tube, which gives rise to both the spinal cord and the brain. Neural crest cells are also created during neurulation. Neural crest cells migrate away from the neural tube and give rise to a variety of cell types, including pigment cells and neurons. Neurulation begins with the formation of a neural plate, a thickening of the ectoderm caused when cuboidal epithelial cells become columnar. Changes in cell shape and cell adhesion cause the edges of the plate fold and rise, meeting in the midline to form a tube. The cells at the tips of the neural folds come to lie between the neural tube and the overlying epidermis. These cells become the neural crest cells. Both epidermis and neural plate are capable of giving rise to neural crest cells. What regulates the proper location and formation of the neural tube? The notochord is necessary in order to induce neural plate formation.
53
describe features you would see in neurulation
primitive streak -\> neural groove -\> somites -\> pharyngeal arches
54
describe what all women have in their ovaries at birth and what stage the follicles are in
at time of birth, 500million primary follicles formed and frozen. Prophase I. they are all hanging out in your ovaries
55
when does the zona pellucida go away?
4-5 days. Allows cells of trophoblast layer to interact with walls of uterus and begin implantation zona falls off close to one week, when embryo arrives at uterine cavity. if it didnt fall off, you'd get an ectopic pregnancy
56
what surrounds the mammalian egg as it is ovulated?
layers of follicle cells and a zona pellucide, a clear membrane
57
describe ovarian cycle vs estrous cycle and then monoestrous or polyestrous
humans use ovarian cycle- once per month, longer cycle, and mestruation. most other mammals use 'estrous cycle' where they do not bleed, Involves shorter luteal cycle . Less endometrial buildup. and a period of heat. monoestrous: cycle occurs 1x per year (deer) polyestrous: cycle occurs multiple times a year (cats)
58
leydig cells
produce testosterone. accessory cell
59
does sperm differentiation involve any division?
no
60
describe fertilization in vertebrates
Multiple sperm trying to get in. first guy gets in. has to work thru zona pellucida. sperms digests thru using lysosomes, meets receptors on plasma membrane. Head of sperm fuses with membrane, membrane of egg fuses only back to head of sperm. Mitochondria (in middle) are left out. (This is the reason why mitochondrial inheritance is maternal) Note the cortical granules: these Release chemicals that signal for zona pellucida to become hard and impermeable when a sperm enters. (as opposed to sea urchins, whose VM jumps up) this is how we prevent multispermy; cortical granule reaction prompts hardening of zona pellucida. Note that we don’t have bindin molecules like sea urchins
61
what is the archenteron and how does it form?
The vegetal plate undergoes primary invagination to produce the archenteron (primitive gut).
62
describe the positive feedback loop that allows the birthing process to occur
hormones (prostaglandins) are the initial signal for contraction Contractions force baby down up against cervix Cervix has nerve endings in it- detects the increased pressure- signal hypothalamus -\> pituitary -\> 2 release oxytocin Oxy dumped into blood , causes smooth muscle contractions that are very strong Baby’s head pushed down even more Enter positive feedback loop- more contractions, more pushing, more head on cervix, etc Cervix is going to dilate and efface; we want it to open and thin out
63
Why doesn't Moms immune system see the baby as a foreign invasion?
embryo trophoblast cells do not make cell surface markers. Moms immune system can’t see the baby as a foreign invasion.
64
surge in what hormone causes ovulation?
LH
65
discuss cleavage differences between protosomes and deuterosomes
in protosomes you see spiral cleavage; the cells leave no space between themselves, maintaining max contact at all times. in deuterosomes, the cells have 'radial cleavage' and stay lined up in a neat stack, with space between them
66
what does HCG (Human chorionic gonadotropin) do?
rescues corpus luteum
67
how does the body herd the ovum into the uterus?
fallopian tubes have fimbrae, fingers , which are lined with cilia and push it in
68
describe what leads to placenta formation around 2-3 weeks- what structures lead to this? how is the child connecting to the mothers blood supply?
the synciotrophoblasts have fused with the uterine wall (endometrium) . now, they form a chorion. the chorion connects to uterine blood supply to form proto-placenta
69
what kind of animals have uterine horns?
ones that deliver litters, like dogs
70
what surrounds the placenta?
amnion
71
the placental hormone, \_\_\_\_\_, stimulates development of milk ducts
placental lactogen
72
glut 1, 3 have km's that are high or low?
low- high affinity for glucose in blood and nervous system
73
glut 2 ; epithelial, liver, km
high km, low affinity, only takes up glucose when we really need it or have a ton
74
purpose of blood islands
increase surface area for gas exchange with maternal blood supply
75
name these structures
a) chorion b) amnion c) amniotic cavity d) yolk sac e) chorionic villi f) blood islands
76
how does the mechanism 2 support the wall of uterus change later in pregnancy
placenta takes over, hcg drops
77
the factor that signals for ovulation 2 occur causes one other critical step in ovary to occur; what is it
further development of corpus luteum, increased secretions of progesterone and estrogen
78
holoblastic vs discoid cleavage
holoblastic: all the way thru, no growth. humans discoid: chicks. no dividing on yolk part
79
relaxin
Loosens the ‘fibro cartilage’ in junction between pubic bones. Happens during birth bc action of ‘relaxin’ hormone. From corpus luteum! Allows brith canal to be larger
80
placental lactogen
prepares boobs 2 become milk factories preps milk ducts milk will be made when it receives prolactin signal, and oxytocin causes it 2 be squeezed out
81
name the hormones that: 1) prepare breast to produce milk 2) create the milk 3 ) eject milk
1. placental lactogen (from placenta) 2. prolactin 3. oxytocin
82
primary induction
two germ layers in close contact; one triggers the other to change or form a new structure
83
when (after what event) is egg officially a zygote?
fusion of pronuclei
84
what factor causes creation of corpus luteum?
ovulation. CL is created when the remaining follicle cells that the egg ruptured out of regroup
85
how long is the CL alive before it degrades into corpus albicans
10 days
86
what event initiates gastrulation?
the infolding of the blastopore (recall that in protosomes, mouth forms first)
87
what stage? name all parts
neurulation A. pharyngeal gil slits B. notochord C. neural tube D. ectoderm E. mesoderm
88
why is no HCL secreted if u cut vagus nerve and put food in mouth
G cells + histamaine not activated if vagus nerve intact, stimulates parietal cells to start secreting acid, and ECL cells
89
function of amnion
The amnion is a membranous sac which surrounds and protects the embryo
90
name the 4 extraembryonic membranes and what they do
amnion- protection / cushioning chorion- connect baby to moms blood supply / develop placenta yolk sac- nourishment allantois- waste removal

bio II, spring (12 decks)

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