Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Endocrine/Repro > Mature Gametes, Fertilization, and Early Embryonic Development > Flashcards

Mature Gametes, Fertilization, and Early Embryonic Development Flashcards

1
Q

identify key features of mature oocytes and sperm that enable successful fertilization

A

male: viable and functional sperm with genomic integrity (good genetics)

females: viable and functional oocytes with genomic integrity AND hormonal regulation for gamete transport and fertilization, support/promote embryonic development, and maintenance of pregnancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

when does sperm maturation begin? describe

A

begins at puberty in the seminiferous tubules, then is a continuous process throughout life to maintain a self-renewing, spermatogonial stem cell population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is spermiogenesis? what happens here? (4)

A

when spermatids develop into sperm

  1. loss of cell cytoplasm
  2. DNA compaction in nucleus
  3. acrosome vesicle formation on the head
  4. mid-piece and tail formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe sperm structure

A

head: haploid nucleus with highly compact DNA and an acrosomal vesicle

tail: midpiece (neck) contains mitochondria and flagellum (the major motor portion is the axoneme)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe sperm capacitation

A

upon release from testis, sperm are motile but CANNOT bind to and fertilize and egg! they must undergo capacitation WITHIN the female tract, which is just a series of reactions to the head and tail make the sperm able to bind to ZP and undergo acrosome reaction including:

  1. plasma membrane reorganization
  2. ion permeability and reorganization
  3. cholesterol loss
  4. changes in phosphorylation state of many proteins
  5. increased sperm motility (hyperactivation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe acrosome reaction

A

this occurs during fertilization, includes the release of acrosomal enzymes induced by contact with the egg’s outer zona pellucida, where the acrosome digests the zona pellucida to permit sperm entry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

describe block to polyspermy

A

accomplished by cortical granule contents from oocyte (hydrolytic enzymes that alter the zone pellucida to block entry of more sperm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe egg activation

A
  1. during fertilization, a sperm activates the egg by inducing Ca2+ oscillations within the egg cytoplasm via a sperm protein factor
  2. calcium signaling activates (3)
    2a. cortical granule exocytosis, which blocks polyspermy and is done BEFORE anything else
    2b. completion of meiosis in the egg
    2c. cell cycle resumption, by decondensing the sperm and egg chromatic to form a 1 cell zygote with one maternal and one paternal pronuclueus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe egg structure (4)

A
  1. large volume of cytoplasm: contains proteins, nutrients, and energy supply, mRNA to encode proteins for early embryo development, and protective chemicals like DNA repair enzymes
  2. cortical granules: located beneath plasma membrane, promote a block to polyspermy
  3. plasma membrane: site of fusion with sperm membrane, regulates ion flow during fertilization
  4. zona pellicuda: extracellular matrix, regulates sperm recognition and binding, also contributes to prevent polyspermy in response to contents from cortical granules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe the zona pellucida (structure and 4 functions)

A

composed of 3 major sulfated glycoproteinsL ZP1,2,3; synthesized and secreted by growing oocyte to form ZP matrix

functions:
1. sperm and egg binding
2. block to polyspermy
3. maintaining preimplantation embryo structure
4. prevention of premature embryo implantatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

which ZP protein is key for egg recognition and acrosome reaction? what does it do?

A

ZP2!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the 6 key processes in fertilization?

A
  1. sperm and egg transport to the ampulla of the oviduct: sperm have to travel a hella long way
  2. sperm capacitation
  3. contact and recognition between sperm and egg
  4. sperm entry into egg
  5. block to polyspermy
  6. egg activation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the 3 key stages in mammalian fertilization?

A
  1. contact and recognition between sperm and egg: to ensure same species
  2. regulation of sperm entry into egg: only one sperm per egg, block polyspermy
  3. fusion of genetic material from sperm and egg: egg activation and resumption of meiosis, formation of diploid embryo (genetically unique from either parent), and initiation of embryonic development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe the mammalian oviduct/fallopian/uterine tube (3)

A
  1. infundibulum: surface is covered in fibria, which capture the oocyte at ovulation and transport it to the opening of the oviduct (ostium)
  2. ampulla: site of fertilization
  3. isthmus: junction with the uterus is the uterotubal junction

epithelium of oviduct supports movement of oocytes and fertilized zygotes with simple columnar epi, ciliated cells, and peg cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what hormone controls gamete transport to the oviduct? how for sperm? (3) how for oocyte? (1)

A

estradiol!

sperm transport:
1. vagina: decreased pH and increased glycogen promotes sperm motility
2. cervix: decreased mucous viscosity facilitates access to uterine cavity
3. uterus: increased contractions help to propel sperm toward oviducts

oocyte transport:
cilia activity and muscle contraction of fallopian tubes propel ovum toward ampulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why is timing of insemination so so important?

A

sperm have variable viability in the female tract, but the oocyte can’t live as long unfertilized!

17
Q

describe development from 2-cell to the blastocyst stage

A
  1. fertilized zygotes resume mitotic division, which initiates embryonic development
  2. in most mammals, the first cleavage to the 2-cell stage occurs 24-36 hours post fertilization
  3. then divide to the 8-cell stage until compaction of the cells into a morula via increase in tight junction formation between cells, production of adhesion, formation of gap junctions and microvilli
  4. morula develops and 2 distinct cell populations arise: blastomeres on outside will form trophectoderm (fetal membranes and placenta) and blastomeres on inside will form the inner cell mass (fetus)
  5. a fluid filled cavity forms (blastocele) as trophectoderm contains Na+/K+ ATPase pumps to draw water in, cavity pushes ICM to one side and now we are a blastocyst!
18
Q

describe regulation/formation of the tissue that will develop into the placenta and the embryo (2 genes)

A
  1. Oct4 gene expression established pluripotency in ICM cells, which will form the embryo (and 3 primary germ layers: endo, meso, ectoderm); Oct4 prevents the differentiation of cells into trophectoderm
  2. Cdx2 gene is essential for trophectoderm differentiation which forms the placenta and extra-embyronic membranes, Cdx2 represses Oct4 in trophectoderm cells

Endocrine/Repro (31 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions