reproduction Flashcards
what prevents polyspermy by destroying the sperm receptors
zips (zonal inhibiting protein)
which stage is the true moment of fertilization
once the chromosomes of the male and female pronuclei are united
what is the definition of cleavage
a period of fairly rapid mitotic divisions of the zygote without intervening growth
how many days after ovulation does the conceptus implant on the uterine wall
six to seven
the corpus luteum is formed at the site of
ovulation
which structures form the placenta
chorionic villi and decidua basalis
when a woman’s water breaks just before delivery it is the —– that ruptures
amnion
glandular organ most likely arise from the —– as they share secretory properties with the gut
endoderm
why is it necessary to send some blood through the pulmonary circuit in a fetus?
the fetal lung tissue requires oxygen for development and growth.
what stimulus triggers parturition?
increased estrogen secretion from the uterus.
increased oxytocin secretion from the mother’s posterior pituitary gland.
increased fetal cortisol secretion.
what stimulates baby to take their first breath?
increased carbon dioxide in the blood.
breast feeding provides several advantages to newborns. for example ———–
breast milk, especially colostrum, is rich in maternal antibodies.
the fat in breast milk is fully absorbed be the infant.
breast milk contains antimicrobial molecules
during development the conceptus is called ————– from fertilization through to week 8 and ———– from week 9 to birth.
embryo
fetus
————– is the process by which sperm become capable of penetrating oocyte.
capacitation
how many sperm are required to break through outer corona radiata of the oocyte for fertilization to occur?
hundreds
trace the path of sperm from spermatogenesis to ejaculation. name the glands and their main products.
testes, epididymis urethra, ductus deferens, prostate gland, seminal vesicle and penis.
outline temperature regulation mechanisms within the scrotum
cremaster muscle - lowers and raises testes inside the abdomen.
Dartos muscle- expands or contracts to wrinkle the scrotal skin.
pampiniform plexus- acts as a heat exchange, cooling blood for adjacent arteries.
explain spermatogenesis? What is spermiogenesis?
the production or development of mature spermatozoa. Spermiogenesis is the final stage of spermatogenesis, which sees the maturation of spermatids into mature, motile spermatozoa.
when do the testes descend?
Testes descend in 7th month. testosterone promotes descent and remains high in infants for 1 month after birth. part of the peritoneum travels down into the scrotal sac and separates from the peritoneum. this forms tunica vaginalis. The tough fibrous cord called the gubernaculum attaches to testes and guides scrotum down. gubernaculum doesn’t change length but guides testes together through the inguinal canal.
outline the HPG axis with respect to the regulation of spermatogenesis. What hormones are involved?
interactions between hypothalamus, anterior pituitary and the testes.
Brain- testicular axis
1. GnRH stimulates the release of GSH and LH commencing at puberty.
2. FSH and LH released.
3. FSH stimulates spermatogenesis by indirectly stimulating ABP (androgen binding protein) release from sustenticular cells or Sertoli Cells allowing testosterone to bind and maintain high concentrations int he seminiferous lumen.
4. LH acts on the interstitial cells of Leydig to produce testosterone.
5. testosterone released into blood. concentrated in testes for spermatogenesis. (essential for meiosis and mitosis and FSH needed for spermatid remodeling.
Stages of male sexual response. What nervous system is dominating?
The sexual response cycle has four phases: excitement, plateau, orgasm, and resolution. autonomic nervous system.
Describe the phases of the ovarian cycle
20 to 45 days in length (typically 28 days) follicular stage: before ovulation stage 1 to 6 follicular phase, stage 7 ovulation, stage 8 luteal phase (luteal phase is after ovulation and always constant)
describe follicular phase
primordial follicle becomes primary follicle when surrounding cell become cuboidal in shape when more than 1 layer forms around the oocyte the follicle is referred to as granulosa cell. connective tissue called theca folliculi forms around the granulosa later together these cell layers produce estrogen zona pellucida production by granulosa cells signals increasing maturity of the follicle becomes late secondary follicle Antrum (clear fluid) bulges. oocyte completes meiosis 1 and becomes a secondary oocyte arrested in meta phase 2.
describe ovulation
bulging follicle ruptures releasing the secondary oocyte into the peritoneal cavity. The oocyte is quickly swept into the Fallopian tubes where fertilization may or may not take place the rise in LH has several effects: signals primary oocyte to complete meiosis 1 to from a secondary oocyte arrested in metaphase 2. Releases enzymes that weakens he ovarian wall near the bulging follicle.
phases of the Menstrual cycle
menstrual phase: proliferative phase : The proliferative phase is the second phase of the uterine cycle when estrogen causes the lining of the uterus to grow, or proliferate, secretory phaseThe next phase of the menstrual cycle is the luteal or secretory phase. This phase always occurs from day 14 to day 28 of the cycle. Progesterone stimulated by LH is the dominant hormone during this phase to prepare the corpus luteum and the endometrium for possible fertilized ovum implantation.
- The order of the ducts through which sperm must travel during ejaculation:
a) Seminiferous tubules, epididymis, ductus deferens, urethra
b) Seminal vesicles, ductus deferens, epididymis, urethra
c) Scrotal sac, epididymis, seminal vesicles, prostate, urethra
d) Seminiferous tubules, ductus deferens, epididymis, urethra
a) Seminiferous tubules, epididymis, ductus deferens, urethra
- The skeletal muscle layer that can alter the position of the scrotal sac is called______
a) Dartos muscle
b) Tunica albuginea
c) Cremaster muscle
d) Both a) and c) are correct
c) Cremaster muscle
- In the male sexual response, erection is controlled by _____________
a) Branches of the sympathetic nervous system which cause vasodilation of
arterioles
b) Somatic nervous system which cause vasodilation of veins
c) Branches of the parasympathetic nervous system which cause vasodilation
arterioles
d) Branches of the sympathetic nervous system which case vasoconstriction of
arterioles
c) Branches of the parasympathetic nervous system which cause vasodilation
arterioles
- In spermatogenesis, which cells of the testes produce androgen-binding protein?
a) Sustentacular cell (sustentocytes)
b) Interstitial endocrine cells of Leydig
c) Spermatogonia
d) Spermatocytes
a) Sustentacular cell (sustentocytes)
28. In a typical negative feedback loop, testosterone produced by the testes inhibits the release of which hormone(s)? a) Gonadotropin releasing hormone (GnRH) b) Follicle stimulating hormone c) Luteinizing hormone d) All of the above
d) All of the above
