concept 3b reproduction Flashcards
SRY gene
sex-determining region Y
on the Y chromosome
codes for the transcription factor that initiates testis differentiation–> formation of male gonads
male reproductive structures
testis seminiferous tubules epididymis vas deferens seminal vesicle ejaculatory duct prostate gland bulbourethral gland urethra penis
testes
have 2 functional components: seminiferous tubules and interstitial cells (of Leydig)
seminiferous tubules produce sperm, they are highly coiled and nourished by Sertoli cells
cells of Leydig secrete testosterone and other male sex hormones (androgens)
testes located in the scrotum and hang below the penis
ejaculation
sperm travel through the vas deferens to the ejaculatory duct at the posterior edge of the prostate gland
2 ejaculatory ducts fuse and form the urethra which carries sperm through the penis
seminal fluid
mixes with sperm as it passes through reproductive tract
produced by seminal vesicles, prostate gland, and bulbourethral gland
combination of this and sperm is known as semen
seminal vesicles
contribute fructose to nourish sperm
give fluid mildly alkaline properties to sperm so they are able to survive acidic conditions of female reproductive system
prostate gland
give fluid mildly alkaline properties to sperm so they are able to survive acidic conditions of female reproductive system
bulbourethral glands
produce clear viscous fluid that cleans out any remnants of urine
lubricates the urethra during sexual arousal
pre cum
spermatogenesis
formation of haploid sperm through meiosis
occurs in seminiferous tubules
spermatogonia–> primary spermatocytes –> secondary spermatocytes–> spermatids–> spermatozoa (mature sperm)
sperm
when matured they are very compact
consists of a head, that contains genetic material
mid piece which generates ATP from fructose (filled with mitochondria)
flagellum for motility
head is covered by acrosome and is necessary to penetrate the ovum
female reproductive structures
ovaries fallopian tube uterus cervix vagina
ovaries
produce estrogen and progesterone
consists of thousands of follicles, multilayered sacs that nourish and protect immature eggs
oogenesis
production of female eggs
all oogonia is produced during fetal development
at birth oogonia have gone through DNA replication and called primary oocytes, they stay in this phase until puberty
after this one primary oocyte per month will complete meiosis I producing secondary oocyte, where it is then arrested in metaphase II until fertilization occurs
oocytes
have 2 layers: zona pellucida and corona radiata
zona pellucida surround oocyte and contains compounds for sperm cell binding
corona radiata is outside the zone pellucida and adhere to oocyte during ovulation
fertilization occurs when sperm penetrates these 2 layers
hormone control on sexual development
before puberty hypothalamus inhibits production of gonadotropin-releasing hormone
at start of puberty this hormone is released and triggers anterior pituitary gland to synthesize and release follicle-stimulating hormone and luteinizing hormone
these hormone trigger sex hormone that develop and maintain reproductive systems
male sex hormones
androgens assist in male sexual differentiation
during childhood androgens are low
testosterone is produced by testes and increases during puberty and sperm production
FSH stimulates Sertoli cells and sperm maturation
LH stimulates interstitial cells to produce testosterone
testosterone
develops and maintains the male reproductive system
role in development of secondary sexual characteristics, hair, deep voice, growth pattern
production remains high through adulthood and declines w/ age
has negative feedback w/ hypothalamus and anterior pituitary to limit production
estrogens
secreted in response to FSH
development and maintenance of female reproductive system and secondary characteristics, breasts, hip widening
in embryo, develops reproductive tract
in adults, leads to thickening of uterus in preparation for implantation of zygote
progesterone
secreted by the corpus luteum in response to LH
development and maintenance of endometrium, not thickening (role of estrogen)
by end of first trimester of pregnancy it is supplied by the placenta, corpus luteum atrophies
menstrual cycle
follicular phase
ovulation
luteal phase
menstruation
follicular phase
begins when the menstrual flow, shedding the uterine lining
decreased levels of estrogen and progesterone
increased FSH and LH
these hormones work to develop ovarian follicles
day 1-14
estrogen begins to regrow uterine line
ovulation
estrogen reaches threshold which causes pink in LH and FSH
surge in LH induces ovulation
ovulation is the release of the ovum from the ovary into the abdominal cavity (and into the fallopian tube)
day 14-15
luteal phase
LH causes ruptured follicle to form corpus luteum which secretes progesterone
progesterone rises and estrogen stays high
progesterone maintains uterine lining for implantation
day 17-28
menstruation
implantation does not occur corpus luteum loses stimulation from LH progesterone levels decline uterine lining is shed decrease in estrogen and progesterone stimulates GnRH to begin next cycle
pregnancy
fertilization has occurred
resulting zygote develops to blastocyst and is implanted in uterine lining
secrete human chorionic gonadotropin (hCG)
menopause
as woman age ovaries are less sensitive to FSH and LH
this results in ovarian atrophy
estrogne and progesterone levels drop, endometrium atrophies and menstruation stops
physical and physiological changes occur, flushing, hot flashes, bloating, headache, and irritability
usually at age 45-55
