12 reproduction Flashcards
testis
each consists of seminiferous tubules for production of sperm and
(Leydig cells)
sertoli cells; testis contained in scrotum- provides external cavity about 2deg
C lower
than body temp for sperm production.
Leydig cells
produces male sex hormones (testosterone + androgens) secreted in the presence of LH;
sertoli cells
stimulated by FSH surround and nurture sperm (also secrete peptide hormone inhibin, acts on the AP to inhibit FSH release)
- provide nourishment “nursing” to spermatids as they differentiate
into mature spermatozoa (sperm). They complete maturation (gain motility and are stored) in the
epididymis.
when do leydig cells secrete testosterone
beginning at
puberty
Epididymis:
coiled tube, one attached to each testis; site for final maturation and storage of
sperm.
Vas deferens:
transfer sperms from one epididymis to urethra.
Seminal vesicles:
Two glands, during ejaculation secrete into vas deferens: provide mucus
(liquid for sperm), fructose (energy for sperm), and prostaglandins (stimulate uterine contractions that
help sperm move into uterus).
Prostate gland:
secretes milky alkaline fluid into urethra; neutralizes acidity of urine that may
still be in urethra, also vagina acidity. Also neutralizes seminal fluid (too acidic from metabolic waste of
sperm)
Bulbourethral glands (aka Cowper’s):
secrete small amount of thick mucus of unknown function into urethra.
Penis:
transport semen (fluid containing sperm and secretions) into vagina.
Sperm:
see notes for more info
PLZ SEE REPRODUCTION VID NOTES
yes
path of sperm
SEVEnUP: seminiferous tubules
epidydmis
vas deferens
ejaculatory duct
urethra
penis -
pause before the V for maturation!
oogenesis
before birth
- oogonia (fetal cells)
(mitosis) primary oocytes
(meiosis) and remain at Prophase I until puberty (one primary oocyte during each menstrual cycle-28days, stim’d by FSH) continue its development through remainder of meiosis I within follicle (encircling cells that protect and nourish oocyte)
(completion of Meiosis I) secondary oocyte (most of cytoplasm) + polar body (small cytoplasm; may or may not divide but products
disintegrate) formed; secondary oocyte arrested at metaphase of meiosis II until
ovulation
ovulation
secondary oocyte from vesicular follicle (caused by LH surge). If fertilized by
sperm
(finishes meiosis II) ovum/egg (diploid once completely fertilized) + polar body (degenerate)
At puberty, FSH stimulates the growth of granulosa cells around the primary oocyte, which release a
viscious substance (zona pellucida). The structure at this stage is a primary follicle. Next theca cells
differentiate from the interstitial tissue and grow around the follicle to form a secondary follicle. Upon
stimulation by LH, theca cells secret androgen which is converted to estradiol (a type of estrogen) by the
granulosa cells in the presence of FSH and secreted into the blood. Typically estradiol inihibits LH
secretion by AP, but just before ovulation, estradiol levels rise rapidly, causing dramatic increase in LH
secretion.
secondary oocyte goes where
briefly located in the body cavity prior to enter the oviduct.
spermatogenesis
- puberty
- Spermatogonia cells
(mitosis) primary spermatocytes
(meiosis) 2 secondary spermatocytes
(meiosis II) 4 spermatids.
Semen
the combination of spermatozoa and the fluids that leave the penis upon ejaculation
Capacitation
allows egg penetration by sperm. final maturation of sperm. changes in sperm intracellular ion cxn, motility, and metabolism
eggs release what?
progesterone which aids in sperm motility and increases the likelihood of
fertilization.
menstrual cycle
proliferative, secretory and menstruation phases (lining shed)
SEE BIO BOOK
for menstrual
menstrual cycle initiation to development of endometrium
Hypothalamus and anterior pituitary initiate: monitor estrogen and progesterone in blood;
Low level stims hypothalamus secretes GnRH, stims AP to release FSH and LH. Follicle develops. FSH stimulate follicle to secrete estrogen, lots of estrogen (positive feedback on hypothalamus). produces GnRH, AP produces sudden midcycle surge of LH, LH Surge triggers Ovulation (follicle is now corpus luteum- develops and maintained by LH
[which along w/ estrogen begins to decrease after ovulation], secretes estrogen + progesterone)
E+ P secretions stimulate
Development of endometrium (thickens in preparation for implantation of fertilized egg)
no implantation cycle
(negative-feedback on AP from ↑e+p) terminates production of FSH + LH (due to ↓GnRH from
hypothalamus)
Corpus luteum (no longer maintained by LH) disintegrates corpus albicans, no estrogen + progesterone endometrium shed during menstruation’s flow phase.
implantation cycle
If implantation occurs embryo (placenta) secretes chorionic gonadotropin (HCG) maintain corpus luteum. Production of e + p remain high endometrium stays HCG is later replaced by progesterone from placenta.
without chorionic gonadotropin
menstruation would begin and the embryo would abort [embryo ‘maintains’
pregnancy]. Pregnancy tests check presence of HCG in urine.
if fertilized egg implants anywhere other than endometrium of the uterus,
it is an ectopic
pregnancy, usually spontaneously aborts
ovarian cycle
has follicular phase, ovulation, luteal phase
follicular phase ovarian cycle
development of egg and secretion of estrogen from follicle [ends at
ovulation]
ovulation
midcycle release of egg.
luteal phase
period
secretion of estrogen and progesterone from corpus luteum after ovulation
[shedding of the uterine lining lasting approximately 5 days]
Estrogen function
thicken endometrium
Progesterone function
development and maintenance of endometrial wall. Progesterone also inhibits lactation during pregnancy. The fall in progesterone after delivery allows for milk production.
male reproduction cycle
influence Sertoli cells to promote development of sperms (nourish sperm during development spermatogenesis). Hormone and gamete production are constant unlike female. LH stimulates the Leydig cells (in the interstitum between seminiferous tubules)
to release testosterone+androgens that promote spermatogenesis in tubules. Sertoli cells
secrete inhibin that acts on the AP to inhibit FSH secretion.
female contraception
female hormonal contraception – estradiol and/or progesterone spiked
artificially high
negative feedback suppresses LH/FSH surge from happening
no ovulation can
occur
no fertilization
please review the feralis notes in conjuction to embryonic development
!!!!
influence of egg cytoplasm
basically yolk crescent stuff is not even, results in axes such as poles and thus daughter cells have different quality of cytoplasmic substances (cytoplasmic determinants). Unique substances influence subsequent development of each daughter cell.
embryonic induction
influence of one cell/group of cells over neighboring cells; organizers
(controller cells) secrete chemicals that diffuse among neighboring cells, influence their development
(Dorsal lip)
homeotic genes
Hox genes in animals. Control of development by turning on and off other
genes that code for substances that directly affect development (e.g. body segments). Homeobox (unique DNA segment-180 nts) identifies a particular class of genes that control development (encodes homeodomain of protein that can bind DNA). The homeobox sequence is highly preserved even across species. Mutations that affect a process as fundamental as segmentation are embryonic lethals (phenotype causes death at
embryo/larval stage).
apoptosis
cell death like nervous system, immune, webbing between toes and fingers etc. ESSENTIAL!!
Induction of cells
occurs when one cell type affects the direction of differentiation for another cell type, and cytoplasmic
determinants also play a role. In the example of a frog: it takes just 4 days for cell division, differentiation, and morphogenesis (the shaping of an organism – can be traced back to changes in shape, motility, and other characteristics of the cells that make up various parts of the embryo) to transform a fertilized frog egg into a tadpole.
three stages of labour
- Cervix thins out and dilates, amniotic sac ruptures and releases fluids
- Rapid contractions followed by birth
- Uterus contracts and expels umbilical cord and placenta
fraternal twins
more than one egg being fertilized (dizygotic – two separate eggs fertilized
by two separate sperm – not genetically identical, no more related than ordinary siblings)
identital twins
indeterminate cleavage (monozygotic – from the same zygote, genetically identical).
Totipotent stem cells
can give rise to any and all human cells, and even an entire functional organism
(morula stage).
Pluripotent
can give rise to all tissue types, but not an entire organism (blastula stage).
Multipotent
can give rise to limited range of cells within a tissue type.
Unipotent:
just one single cell
type.
please review this chapter as it has extra stuff in notes after embryology video
pls (og 93)
placental ciruclation
occurs across the
villi that extend from the chorionic membrane surrounding the fetus. Oxygen depleted fetal blood travels to the villi through the fetal arteries and returns oxygenated through the fetal veins. Blood flowing from the mother fills in pools that surround the chorionic villi and allow the passage of nutrients and gas between the fetal and maternal circulatory systems. It is important to recognize that maternal and fetal circulatory systems are not continuous (not directly connected).
in vitro (IVF)
in vitro looks at cells/biological molecules outside their normal biological
context (e.g. in a lab). and IVF with microinjection is more effective than regular IVF
in vivo
In vivo is w/in normal bio environment. Natural conception (“in vivo”) has a higher success rate than IVF (normally)
first trimester
and IVF with microinjection is more effective than regular IVF
second trimester
fetus be active and belly be noticeable
3rd trimester
bb grows to 7 lbs
calcium levels and pregnant woman
During pregnancy it is important for the mother to maintain
adequate Calcium levels, or the developing fetus will resorb it from the mother’s skeleton.
