Reproduction Flashcards
Humans have how many homologous chromosomes?
46
What is the gene found in the Y chromosome that induces teste formation?
SRY (sex-determining region Y)
For how many days of gestation are gonads of both sexes similar?
40 days
If SRY is present, what happens to the gonads around day 45 of development?
Seminiferous tubule formation
These cells (in addition to germ cells) comprise the seminiferous tubules in early development
Sertoli (sustenacular) cells
These cells begin appearing around day 65 in the presence of the SRY gene; secrete testosterone
Interstitial Leydig cells
This term describes the lack of testicular descent
Cryptorchidism
What are some reasons why testicular descent occurs in males?
To keep temp low enough for spermatogenesis (~35C)
The testes secrete what hormone?
Testosterone
The ovaries secrete what hormones?
Estrogen and progesterone
This hormone is secreted by Serotoli cells to induce the degeneration of the structure that would form the uterus
MIF (Mullerian inhibition factor)
Without the presence of MIF in a fetus, what will occur>
Uterus and uterine tube formation
Testosterone induces the change of Mesospheric (wolffian) duct into what structures?
Epididymides, ductus deferens, ejaculatory ducts
Without the presence of testosterone, what happens to the Mesonephric (wolffian) duct?
Degenerates
This is the site of spermatogenesis; upon exiting the testicle, they form the epididymis
Seminiferous tubules
These occur between the lobules of the seminiferous tubules and actively produce testosterone
Interstitial cells of Leydig
When the seminiferous cells exit the testicle, they form into this structure; nourishes sperm during final maturation
Epididymis
What is the time period of the final maturation of sperm in the epididymis?
1-2 weeks
This structure originates from the epididymis and is joined by the seminal vesicle prior to the prostate; transfers matured sperm from testicle
Vas deferens
This structure produces an alkaline secretion to neutralize the low vaginal pH
Seminal vesicle
The seminal vesicle produces about what percentage of semen volume?
60%
This is a gland below the base of the bladder that surround the urethra to add secretions to semen
Prostate gland
The prostate gland secretions consist of what percentage of the final semen volume>
30%
This structure also produces an alkaline secretion that behaves as a urethral lubricant
Bulbourethral glanda
The bulbourethral glands produce what percentage of the final semen volume
5%
This hormone is secreted by the hypothalamus to regulate the pituitary release of FSH and LH
GnRH (gonadotropin releasing hormone)
GnRH regulates the pituitary release of what hormones
Follicle stimulating hormone (FSH) and luteinizing hormone (LH)
GnRH secretion increases significantly during what phase?
Puberty
This hormone stimulates the release of testosterone from the interstitial cells
LH (leuteinizing hormone)
Rising testosterone levels in response to LH hormone secretion results in what? (3)
Spermatogenesis, systemic virializing effects, inhibition of FSH/LH
This hormone increases the rate of spermatogenesis
FSH (follicle stimulating hormone)
What are the outcomes of increases FSH release in males (not including spermatogenesis)
ABP production (via Sertoli cells)
Testosterone hording
Inhibin production
This Sertoli cell secretion hoards testosterone around spermatogenic cells in response to elevated FSH
ABP (androgen binding protein)
This hormone is produced by sertoli cells in response to high sperm count to shut down FSH
Inhibin
What are the names of the cell produced during spermatogenesis
Spermatogonia —> spermatocytes —> spermatids —> spermatozoa
These are premeiosis sperm cells
Spermatogonia
These are cells that will immediately undergo meosis 1 but havent yet
Primary Spematocytes
These are sperm cells that hae undergone meiosis 2
Spermatids
These are spermcells that hae ungergons maturation after meiosis 2
Spermatozoa
At what stage do sperm cells stop at before elevated testosterone levels in puberty
Meosis 2
What receptors do the sertoli, sperm cells, and epididymis have
E2 receptors
This is an important paractine regulator of spermatogensis; can be manufactured from testosterone
E2 / estrogen
What is lost from sperm cells by the time they mature into sperm?
Cytoplasm and most unneeded organelles
Amout how many sperm are in ejaculate
10^8 / mL
This prt of a sperm contains digestive enzymes to penetrate egg
Acrosome
This part of a sperm cell contains the nucleus
Head
This parto f the sperm contains the mitochondria
Midpieces
This part of the sperm contains nmicrotubular flagellum
Tail
Metaphase 2 of oogenesis will only complet under what conditiona
Fertilization
What are the cell names of egg cells during oogenesis
Oogonium —> primary oocyte —> secondary oocyte —> zygote (fertilization)
Awhat happens to the poar body of the first mieotic division of oogenesi
Degenerates
How many ooctes at birth
2 million
how many oocytes by puberty
400,000
How many oocytes ovulate
400
At what stage do oocytes arrest in until oogenesis
Prophase 1
These cells surroud each oocyte to form primary follicles
Granulosa cells
FSH in females does what to the granulosa cells
Stimulates proliferation in some to become secondary follicles
This is the name of a follicle that has ungergone much FSH stimulation and contains a lare fluid filled space
Graafian follicle
This is the large fluid filled space of the graafian follicle
Antrum
This is the name of the layer of granuola cells that surroune the oocyte in a graafian follicle
Corona radiata
This is the small atttachment of the oocyte between the granulosa cells and the corona radiata
Cumulus oophorus
This is a layer of protein and polysaccharides that prevent penetration by sperm; requires digestion
Zona pellucida
By day 14 of the menstrual cycle (1 day of period) this is the key concept progression
Graafian follicle becomes progressively larger —> creates more granulosa cells —> produces more E2
a spike in E2 at around day 12 releases a huge surge of what hormone>
LH (leutinizing hormone)
A surge of LH around day 12 results in what event in the ovary?
Ovulation
The released oocyte is captured by what structure?
Fimbria
For about how many days does the corpus luteum grow
10 days
This is a result of LH stimulation of granulosa cells; secretes increasing amounts of hormones to prepare for implantation
Corpus luteum
This is what the corpus luteum becomes after it scars from not recieveing a fertilized egg
Corpus albicans
3 phases of menstrual cyle
Menstrual
Proliferative
Secretory
How long is the menstrual cycle
28 days
A peak in FSH results in the stimulation of the ovarian folicles and granulosa to do what
Grow and produce estrogen
A large surge of estrogen (then LH 12-24 hours later) induces what?
Ovulation
Body temp increases by what during ovulation?
0.8C
When fertilization does not occur, what happens to hormones?
Progesterone levels fall
What is the response to falling progesterone levels after failed implantation of fertilizaed egg?
Menstruation 3 days later
This is the phase of the menstrual cycle where the endometrial lining of the uterus grows (due to increased E2 and progesterone)
Secretory phase
How long are sperm viable after intercourse?
Several days
What is the time frame that fertiliztion must occur after ovulation
Within 24 hours
Sperm entry into the egg results in what
Calcification of the membrane to prevent additional sperm entry + induce meiosis of egg cell
The blastocyst releases this hormone after successful implantation occurs
hCG (human chorionic gonadotropin)
Estrogen and progesterone are continuously produced after implantation for wht reason?
To prevent menses