fertilization

biom 3200

what are mature gametes (examples)

spermatozoon and oocyte

what are mature gonads (examples)

testes and ovaries

male sperm transport: where is infertile spermatozoa transported for spermiation

epididymis

sperm transport in males: duration

4-12 days

sperm transport in males: what secretions does spermatozoa mix with upon ejaculation

fructose and prostaglandins from seminal vesicles, and citric acid, zinc, magnesium ions from prostate gland

sperm transport in female: what does sperm do to vaginal pH

raise it

sperm transport in females: where does sperm transport through and enter

uterus/ uterine horns, enter into oviducts

sperm transport in females: how is sperm passed up through oviducts

flagellar movement and contractions of oviducts

sperm transport in females: what protects spermatozoa from acidity in upper vagina

seminal fluid

sperm transport in females: pH goes from __ to __ in __ seconds

4.3 to 7.2 in 10 seconds

sperm transport in females: what pH is optimal for sperm motility to reach the cervix

6-6.5

2 functions of the cervix for sperm transport

barrier to spermatozoa and sperm reservoir

why is the cervix inhabitable and hostile to sperm

it is viscous and gelatinous

what in the cervix inhibits sperm travel

cervical rings and folds

what does sperm get trapped in in the cervix

crypts

sulfomucin in the cervix

viscous, prevents sperm motility sialo

sialomucin in the cervix

watery, facilitates sperm motility

when is cervical mucous the thickest

menstruation and luteal phase

when is cervical mucous the thinnest

ovulation

sperm transport in female: rapid transport in the cervix

spermatozoa penetrate sialomucin, move through cervical canal by contractions, reach the uterus

sperm transport in female: slow transport in the cervix

spermatozoa swim through mucous, slow release of stored sperm

capacitation of spermatozoa

Structural changes in the sperm cells that occur in the female reproductive tract that prime sperm for fertilization

what does capacitation enable

zona pellucida penetration

what happens when the dominant follicle ruptures

the cumulus oocyte complex is released

what captures the cumulus oocyte complex

fimbria of the infundibulum

what happens to the cumulus oocyte complex once in the oviduct

ciliated epithelium guides it deeper towards the ampulla

what happens to sperm once it reaches the COC in the ampulla

cumulus cells are removed

what mediates the removal of cumulus cells

hyaluronidase (hydrolytic enzyme), and sperm motility (disrupts cloud)

what do zona pellucida proteins prevent

other spermatozoa from entering ovum after fertilization

what does binding to zona pellucida proteins trigger

acrosome reaction

what is the acrosomal reaction

it exposes the inner acrosomal membrane and fusion proteins

sperm oocyte fusion: before membrane fusion steps

after ZP penetration, cortical granules migrate to periphery of oocyte, then oocyte PM fuses with equatorial segment

sperm oocyte fusion: during membrane fusion steps

immediate membrane depolarization and sperm is engulfed, cortical granules released into perivitelline space

sperm oocyte fusion: after membrane fusion steps

sperm nuclear membrane disappears, nucleus decondenses

what is membrane depolarization triggered by

influx of Na+ ions from NaK+ ion pumps

what does membrane depolarization result in

electrical barrier to sperm entry

what enzymes are released in cortical granule reaction

peroxidases, glycosaminoglycans, and proteases

peroxidases function in cortical granule reaction

harden glycoproteins to form impenetrable layer

glycosaminoglycans function in cortical granule reaction

attract water into the perivitelline space (fertilization envelope)

proteases function in cortical granule reaction

destroy sperm binding sites, prevent other sperm from binding to ZP proteins

what do calcium oscillations allow

DNA synthesis to begin and cell cycle to resume

completion of meiosis results in

female pronucleus

what forms the male pronucleus

sperm nucleus decondensing

what draws the two pronuclei together (zygote formation)

sperm centriole forms microtubules that integrate with ovum microtubules

steps of two pronuclei fusion (zygote formation)

cell membranes break, chromatin from both mix before condensing into chromosomes, embryonic development begins

after how much time of unprotected sex is it considered infertility

1 year

what is in vitro fertilization

oocytes harvested and fertilized in lab, embryo transferred to carrier

classic IVF

maturation: oocyte maturation

fertilization: incubate with sperm

cell culture: incubate until hatched blastocyst

intracytoplasmic sperm injection

treats male sterility, assesses sperm quality, injects sperm into secondary oocyte cytoplasm

what forms the early embryo

initial divisions of zygote

what are blastomeres

forms during cleavage stage, rapid mitotic divisions with no growth phases

blastomeres are __ up until 8-cell stage

totipotent (can develop into any type of cell in the body)

when do blastocysts hatch

prior to implantation

epiblast (bilaminar disk of embryonic disk)

maternal portion

hypoblast (bilaminar disk of embryonic disk)

embryonic portion

what does the ectoderm involve

integumentary system and nervous system

what does the mesoderm involve

circulatory system, integumentary system, musculoskeletal system, and urogenital system

what does the endoderm involve

digestive system, glandular system, and respiratory system

germinal period

fertilization until implantation (zygote until embryonic disk)

embryonic period

gastrulation until 8th week of pregnancy

fetal period

9th week of pregnancy until birth

what is necessary to maintain a pregnancy

elevated levels of estrogen and progesterone

embryonic cleavage

corpus luteum synthesizes

P4 and E2 for corpus luteum synthesis

P4 keeps endometrium intact, P4 and E2 inhibits pituitary gland

estriol (E3) for pregnancy maintenance

uterine myometrium receptors, oxytocin receptors, breast ducts development

progesterone (P4) in pregnancy maintenance

suppresses uterine contractions, cervical plug, and milk glands

PTHrP (parathyroid hormone related peptide) in pregnancy maintenance

mobilizes moms bone calcium

CRH (corticotropin releasing hormone) role in maintaining pregnancy

fetal lung maturation