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KCUMB Embryology > EXAM I > Flashcards

EXAM I Flashcards

1
Q

Following fertilization, when do the primordial germ cells first appear?

A

Endodermal layer of yolk sac

24 hrs after fertilization

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2
Q

Trace the migration route of the primordial germ cells into the developing gonads from the yolk sac

A

Endodermal yolk sac —> hind gut epithelium via dorsal mesentery —> developing gonads

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3
Q

What are the stages of meiosis? List substages of prophase with what occurs at each stage

A

PMAT I

PMAT II

(Little Zebras Play Dirty Deeds)

Leptotene - chrom begin to coil, each chrom = 2 chromatids

Zygotene - homologous chrom pair (synapsis), synaptonemal complex forms

Pachytene - tetrads, start of crossing-over

Diplotene - crossing-over, chiasmata well defined

Diakinesis - finish crossing-over, nuclear membrane disrupted, spindle apparatus

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4
Q

What are the major events in meiosis?

List the major results of meiosis?

A
  • Synapsis (pairing of homo. chrom.), crossing-over, two cell divisions w/ 1 DNA replication cycle (n)
  • Non-identical and haploid daughter cells, increase in cell number
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5
Q

Define aneuploidy and euploidy, what are the types?

A

Euploidy - changes in complete set # of chromosomes

  • Monoploidy, Diploidy (normal), Polyploidy

Aneuploidy - abnormal chrom. number (via nondisjunction)

  • Monosomy, Trisomy
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6
Q

Compare the total number of oocytes that are present early in embryonic development to the number present at birth and prior to puberty.

A

Embryonic midterm - 7 million

Birth - 2 million

Puberty - 400,000 (arrested in diplotene)

Post-puberty - 400

Most become atretic

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7
Q

Describe the structure/layers of the mature follicle

A

external —> internal

Theca externa - produce angiogenesis factor

Theca interna - LH receptors, secrete testosterone

Membrana granulose

Mural granulosa cells - FSH receptors

Antrum

Cumulus/Oophorus cells - facilitates release of ovum at ovulation

Zona pellucida

Oocyte

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8
Q

Describe the meiotic state of the oocyte at puberty and prior to ovulation

A

Until puberty - diplotene of prophase I (primary oocyte)

Pre-Ovulation - metaphase II (until fertilization)

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9
Q

What is the role of LH in ovulation?

A

LH surge occurs causes ovulation; resuming of meiosis to arrest in Metaphase II - shuts down gap junctions b/w granulosa cells and oocyte, reducing [cAMP], allowing MPF activation

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10
Q

What are the factors that lead to meiotic arrest at the diplotene stage of meiosis

A
  1. Hight [cAMP] from oocyte and follicular cells (inactivating MPF)
  2. cGMP from follicular cells that inactivate phosphodiesterase 3A in oocyte (preventing the conversion of cAMP to 5’AMP, maintains high [cAMP]
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11
Q

What are the fates of the follicle after ovulation occurs?

A

Becomes the corpus luteum and secretes progesterone

Eventually degenerates

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12
Q

Define, compare, and contrast spermatogenesis and spermiogenesis

A

Spermatogenesis - Development of mature sperm

Spermiogenesis - maturation of spermatids to motile spermatozoa

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13
Q

List the stages of spermatogenesis (5)

A
  1. Primordial germ cells (2N); developing yolk sac
  2. Spermatogonia (2N); Type A stem cells, Type B
  3. Primary Spermatocytes (2N, 4c); meiosis I
  4. Secondary Spermatocytes (N, 2c); meiosis II
  5. Spermatids (N, 1c); x4 cells
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14
Q

List the two major differences between one cycle of oogenesis and once cycle of spermatogenesis

A

Two secondary spermatocytes (1n, 2c)

1 secondary oocyte + polar body

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15
Q

What is the location and function of the cells of Leydig?

A

Interstitial cells inside the testis

Produce testosterone

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16
Q

List the four stages of spermiogenesis and the major events that occur during each of the four stages

A

GCAM - Girls Call Abnormal Men

  1. Golgi phase - proacrosomal vesicles, acrosomal vesicles
  2. Cap phase - mature acrosome forms a cap over nucleus
  3. Acrosomal phase - sperm rotates so that acrosomal pole faces wall of seminiferous tubule, cytoplasm eliminated from tail for motility
  4. Maturation phase - completion of flagellum and nuclear condensation
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17
Q

Where are sertoli cells located?

A

Seminiferous tubules of the testes

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18
Q

What are the functions of the sertoli cells? (6)

A
  • Physical support and maintenance
  • Maintain and coordinate spermatogenesis
  • Secrete estrogen, inhibin, and anti-Mullerian factor
  • Maintain the blood-testes-barrier
  • Secrete tubular fluid
  • Phagocytize residual bodies of sperm cells
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19
Q

What is the role of testosterone in the blood testes barrier?

A

Stimulates the formation of a new BTB closer to the basal lamina

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20
Q

What is the action of LH on interstitial cells and Sertoli cells in regards to sperm cell production?

A
  • LH - activates LH receptors on interstitial cells of Leydig, causing cholesterol synthesis
  • Sertoli cells receive the testosterone and to secondary sex tissues
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21
Q

Based on your knowledge of paralogous groups, which gene would be expressed most anteriorly in the embryo?

Hoxa-13

Haxc-9

Hoxd-13

Hoxb-1

Hoxb-6

A

Hoxb-1

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22
Q

Which of the following produces testosterone in the testis?

Sertoli

Leydig

Granulose

Spermatogonia

A

Cells of Leydig

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23
Q

What forms the corpus luteum?

Corona radiata

Thecal

Granulosa

Thecal and granulosa

A

Granulosa Cells

Thecal Cells

24
Q

What the the site of fertilization?

Ampulla

Isthmus

25
In mammalian embryo, unlike non-mammalian and invertebrates, most transcription via the embryonic genome as opposed to maternal genome, occurs as early as which... Zygote 4-Cell Stage Blastula Gastrula
4-Cell Stage
26
In drosophila, from which of the following categories are mRNAs derived from maternal genome rather than embryonic? Egg-polarity genes Pair rule genes Homeotic genes Gap genes
Egg-polarity genes
27
Which of the following is a TF FGF Pax TGF Notch Wnt
Pax
28
Zinc fingers or helix loop helix arrangements are characteristic of members of which class of molecules? Proto Oncogenes Signaling Molecules Receptors Transcription factors None of the above
TFs
29
Shh is produced in which signaling centers Notocord Intestinal portals Floor plate of the neural tube Zone of polarizing activity in limb bud All of the above
All of the above
30
The principal energy source for ejaculated spermatozoa is Prostatic acid phosphatase Internal glucose Prostatic citric acid Fructose seminal vesicle fluid
Fructose seminal vesicle fluid
31
Of the barriers to sperm survival and transport within the female reproductive tract, low pH is most important in the: Upper uterine tube Lower uterine tube Uterine cavity Cervix Vagina
Vagina
32
During the menstrual cycle a sharp spike in plasma levels of which of the following levels just before ovulation is responsible for ovulation? FSH LH Estrogen Progesterone Estradiol-17 beta
LH
33
Transcription of which of the following genes is required to permit cleavage to proceed to the 2-cell stage in embryos? Nanog 4-Oct Cdx 2 Sox 2
4-Oct
34
The principal inductor in primary neural induction is the: Hypoblast Primitive streak Extraembryonic mesoderm Notochordal process Embryonic ectoderm
Notochordal process
35
Cells of which germ layer are not present in the oropharyngeal membrane? Ectoderm Mesoderm Endoderm All are present
Mesoderm
36
Brachyury, a deficiency in caudal tissues in the body, is caused by a mutation in what gene? Lim-1 Noggin T Sonic hedgehog Activin
T
37
Hypoblast is a bilaminar, early embryo gives rise to which of the following tissue types? Extraembryonic only Embryonic only Embryonic and extraembryonic Neither
Extraembryonic only
38
In meiosis, pair of homologous chromosomes begins during which of the following stages of prophase I? Letotene Zygotene Pachytene Diplotene
Zygotene
39
Which of the following description best describes the oogonium and the ovary during the early fetal period? Diploid, no follicle Diploid, few follicle cells Haploid, no follicle Haploid, few follicle cells
Diploid, no follicle
40
Inhibin released by the granulose cells during the mammary cycle inhibits secretions of gonadotropins especially FSH. Resulting in which of the following Regression of the corpus luteum
Regression of the corpus luteum
41
Splitting of the blastocyst during early development, results in the two complete blastocyst enclosed within a single trophoblast is the most common mode of twinning. Assuming complete normal identical twins result of what development property is illustrated? Differentiation Determination Regulation Morphogenesis
Regulation
42
During spermatogenesis, histone is replaced by which of the following, to allow better packing of the condensed chromatin in the head of the spermatozoon? Inhibin Prostaglandin E Testosterone Protamine Androgen-binding protein
Protamine
43
Which cell type is located outside the blood testis barrier? Spermatozoon Secondary spermatocyte Spermatid Primary spermatocyte Spermatogonium
Spermatogonium
44
Which of the following cells normally participates in mitotic division? Primary oocyte Oogonium Primary spermatocyte Spermatid Secondary spermatocyte
Oogonium
45
Role of Cdx2 gene
Trophoblast cell differentiation
46
State the role of Oct-4
**Permits cleavage to proceed to 2-Cell stage**
47
State role of Nanog, what produces it?
Maintains ICM integrity Produced by ICM in late morula stage Without nanog = ICM differentiates into endoderm Without Oct-4 = ICM differentiates into trophoblast
48
State the role of Sox2
Helps control regulation of genes involved in differentiation ## Footnote **First expressed in 8-cell stage**
49
Define Bateson's rule
Duplicated structures are joined during critical developmental stages ## Footnote **Mirror Images**
50
Functions of ZP
* **Promotes oocyte & follicle maturation** * **Barrier** * **Initiates acrosomal reaction** * **Prevents polyspermy** * **Acts as a porous filter where certain substances can reach the embryo** * **Immunological barrier b/w mother & embryo** * **Facilitates trophoblast cell differentiation** * **Prevents premature implantation of embryo**
51
What is the most common condition associated with spontaneously aborted embryos? Maternal imprinting Paternal imprinting Ectopic pregnancy Chromosomal abnormalities Lack of X-chromosomeal inactivation
Chromosomal abnormalities
52
What tissue from the implanting embryo directly interfaces with the endometrial connective tissue? Corona radiata Inner cell mass Extraembryonic mesoderm Epiblast Syncytiotrophoblast
Syncytiotrophoblast
53
Which of the following tissues arises from cells passing through the primitive streak? Embryonic endoderm Hypoblast Cytotrophoblast Primary yolk sac Amnion
Embryonic endoderm
54
Identical twinning is made possible by what process or property of the early embryo? Regulation Aneuploidy Paternal imprinting Maternal imprinting X-chromosomal inactivation
Regulation
55
The Zone pellucida: Aids in penetration of the endometrial epithelium Serves as a source of nutrients for the embryo Prevents premature implantation of the cleaving embryo All of the above None of the above
Prevents premature implantation of the cleaving embryo
56
The prechordal plate plays an important role in regionalization of the: Notochord Forebrain Embryonic mesoderm Primitive node Hindbrain
Forebrain

KCUMB Embryology (4 decks)

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