MCAT Biology Reproductive System Part 2 Flashcards
The primary androgen (male sex steroid) produced and secreted by the interstitial cells of the testes. It triggers development of secondary male sex characteristics during puberty (including spermatogenesis) and maintains those characteristics during adulthood
Testosterone
A layer of cells surrounding the granulosa cells of the follicles in an ovary.
Thecal cells
__ help produce the estrogen secreted from the follicle during the first phase of the ovarian cycle
Thecal cells
The outer ring of cells of a blastocysts. The __ takes part in the formation of a placenta
Trophoblast
The __ contains fetal arteries (carry blood toward the placenta) and veins (carry blood away from the placenta). The __ derives from the allantois, a structure that develops from the embryonic gut
Umbilical cord
The tubes that carry urine from the kidneys to the bladder
Ureters
The shedding of the old endometrium and preparation of a new endometrium for potential pregnancy
Uterine cycle
These tubes extend laterally from either side of the uterus and serve as a passageway for the oocyte to travel from the ovary to the uterus. This is also the normal site of fertilization. Severing of this results in sterility of females
Uterine tubes
The muscular female organ in which a baby develops during pregnancy
Uterus
The birth canal; the stretchy, muscular passageway through which a baby exits the uterus during childbirth
Vagina
Paired glands near the posterior of the vaginal opening that secrete an alkaline mucus upon sexual arousal. The mucus helps to reduce the acidity of the vagina (which could be harmful to sperm) and lubricates the vagina to facilitate penetration
Vestibular glands
Early embryonic ducts that can develop into male internal genitalia under the proper stimulation (testosterone)
Wolffian ducts
An embryonic structure particularly important in egg-laying animals because it contains the yolk, the only source of nutrients for the embryo developing inside the egg. In humans the __ is very small and is the site of synthesis of the first red blood cells
Yolk sac
A thick transparent coating rich in glycoproteins that surrounds an oocyte
Zona pellucida
The site of spermatogenesis are ___
seminiferous tubules
Leydig cells are responsible for __
angrogen (testosterone) synthesis
__ is located at the posterior surface of the bladder and secretes about 60% of total semen into the ejaculatory duct
Seminal vesicles
____ secretions give nourishment to semen and allow them to coagulate after ejaculation
Prostate glands
What three compartments in male reproductive system contain erectile tissue?
- corpora cavernosa (two of them)
- corpus spongiosum
Arousal is dependent on ___ and orgasm is dependent on stimulation from__
parasympathetic nervous input
Sympathetic nervous system
___ is the movement of sperm and semen into the urethra; ___ is the movement of semen from the urethra out of the body
Emission is movement into the urethra, ejaculation is movement from urethra out of body
Process by which diploid germ cells undergo division to produce haploid gametes
Gametogenesis
Gametes produced by male are known as___
spermatozoa
Female gametes are known as ___
ova or eggs
Cells that give rise to spermatogonia are known as__
germ cells
___ stimulates the interstitial cells to secrete testosterone
Luteinizing hormone (LH)
___ stimulates the sustenacular cells (SERTOLI CELLS)
Follicle stimulating hormone (FSH)
The hormone __ is secreted by sustenacular cells, its role is to inhibit FSH release
Inhibin
__ can develop into male internal genitalie:
- epididymis
- seminal vesicles
- ductus deferens
Wolffian ducts
___ can develop into female internal genitalia:
- Uterine tubes
- uterus
- vagina
Mullerian ducts
___ is produced by the testes and causes regression of the Mullerian ducts; prevents the development of female internal genitalia
Mullerian inhibiting factor (MIF)
Testosterone that is responsible for the development of male external genitalia enters the systemic circulation and must be converted to __ in target tissues in order to exert its effect
Dihydrotestosteronei
How would an RNA polymerase 2 inhibitor alter the effects of dihydrotestosterone in target cells?
Once its ligand is bound, the steroid receptor activates transcription of specific mRNA. Messenger RNA is transcribed by RNA polymerase 2. Therefore we would expect an inhibition of polymerase 2 to prevent the effects of all steroid hormones
In women, FSH stimulates _____
FSH stimulates granulosa cells to secrete estrogrn
In women, LH stimulates___
formation of the corpus luteum and progesterone secretion
Oogonia not only undergo mitosis in utero but they also enter the first phase of meiosis and are arrested in __ as primary oocytes
Prophase 1
The primary oocyte and granulosa cells make up what is known as __
a follicle
What are the three phases of the ovarian cycle?
Follicular phase (13 days) Ovulatory phase (day 14) Luteal phase (about 14 days
What occurs during the follicular phase of the ovarian cycle?
Primary follicle matures and secretes estrogen. Maturation of the follicle is under the control of follicle stimulating hormone (FSH) from the anterior pituitary gland
What occurs during the ovulatory phase?
Secondary oocyte is released from the ovary, triggered by a surge of leutenizing hormone (LH) from the anterior pituitary. This causes the remnants of the follicle to become the corpus luteum.
What occurs during the luteal phase?
Begins with full formation of the corpus luteum in the ovary. This structure secretes both estrogen and progesterone and has a life span of about 2 weeks.
What are the 3 phases of the Uterine cycel?
Menstruation (first 5 days) Proliferative phase (9 days) Secretory phase (14 days)
__ is triggered by the degeneration of the corpus luteum and subsequent drop in estrogen and progesterone levels, this causes the endometrial lining to slough out of the uterus
Menstruation
During __ of the menstrual cycle, estrogen produced by the follicle induces the proliferation of a new endometrium
Proliferative phase
After ovulation the __ occurs, in which estrogen and progesterone produced by the corpus luteum further increase development of the endometrium, including secretion of glycogen, lipids, and other material. If pregnancy does not occur, death of the corpus luteum and decline in the secretion of estrogen and progesterone trigger menstruation once again.
Secretory phase
When ovulation occurs the endometrium is at the __
proliferative stage, under the influence of ovarian estrogen
Where is the secondary oocyte during the secretory phase?
It is traveling down the uterine tube toward the uterus. If it fails to implant in the uterus, the secretory phase ends and menstruation begins
_____ from the hypothalamus stimulates release of FSH and LH from the anterior pituitary
GnRH
Under the influence of FSH, the granulosa and thecal cells develop during the follicular phase and secrete __
estrogen
The sudden surge in __ causes ovulation
LH
If LH levels remained high, how would this affect the secretion of estrogen and progesterone?
If LH levels remained high, the corpus luteum would not regress, and estrogen and progesterone would also remain high, thus maintaining the endometrium so that menstruation would not occur. This is an effect that happens if an embryo is fertilized and implants, except that the hormone in this case is not LH but hCG
The ___ is the portion of hte placenta that is derived from the zygote, it secretes hCG
Chorion
What are the two components of the cortical reaction?
- swelling of the space between the zona pellucida and the plasma membrane
- Hardening of the zona pellucida
The inner cell mass of the blastocyst gives rise to what four things?
- embryo
- yolk sac
- allantois
- amnion
The ___ develops from the embryonic gut and forms the blood vessels of the umbilical cord which transports blood between embryo and placenta
Allantois
The ___ gives rise to the anus
Blastopore
The entire nervous system pituitary gland( (both lobes) adrenal medulla cornea lens epidermis of skin and derivatives (nails, hair, sweat glands, sensory receptors) -nasal, oral, anal epithelium
Ectoderm
- All muscle, bone, and connective tissue
- entire cardivascular and lymphatic system (including blood)
- urogenital organs (kidneys ureters, gonads, reproductive ducts)
- DERMIS of skin
Mesoderm
- GI tract epithelium (except mouth and anus)
- GI glands (liver pancreas)
- Respiratory epithelium
- Epithelial lining of urogenital organs and ducts
- Urinary Bladder
Endoderm
Primitive cells in the zygote and the morula have the potential to become any cell type in the blastocyts, they are therefore kown as __
totipotent cells
The fetus looks distinctly human during the __
Second trimester
This is the stage of rapid fetal growth, organs become fully functional
Third trimester