Reproductive system

ilm1993's version from 2017-07-26 01:44


Question Answer
Testicular regulation involves three sets of hormonesGnRH, which indirectly stimulates the testes through: (FSH) and Luteinizing hormone (LH)
Gonadotropinswhich directly stimulate the testes
Testicular hormones, whichexert negative feedback controls

Hormonal Regulation of Testicular Function

Question Answer
1The hypothalamus releases gonadotropin-releasing hormone (GnRH)
2GnRH stimulates the anterior pituitary to secrete FSH and LH
3FSH causes sustentacular cells to release androgen-binding protein (ABP)
4LH stimulates interstitial cells to release testosterone
5ABP binding of testosterone enhances spermatogenesis

Testosterone activity

Question Answer
Testosterone is synthesized fromcholesterol
Target cellsProstate (it is converted into dihydrotestosterone (DHT) before it can bind within the nucleus) and Neurons (it is converted into estrogen to bring about stimulatory effects)
Testosterone targetsall accessory organs and its deficiency causes these organs to atrophy


Question Answer
Each follicle consists of an immature egg called anoocyte
Follicle cellsone cell layer thick
Granulosa cellswhen more than one layer is present
Primordial follicleone layer of squamouslike follicle cells surrounds the oocyte
Primary follicletwo or more layers of cuboidal granulosa cells enclose the oocyte
Secondary folliclehas a fluid-filled space between granulosa cells that coalesces to form a central antrum
Graafian folliclesecondary follicle at its most mature stage that bulges from the surface of the ovary
Ovulationejection of the oocyte from the ripening follicle
Corpus luteumruptured follicle after ovulation

Ovarian Cycle

Question Answer
Follicular phaseperiod of follicle growth (days 1–14); Primary follicle becomes a secondary follicle, The secondary follicle becomes a vesicular follicle
Luteal phaseperiod of corpus luteum activity (days 14–28)
Ovulation occursmid cycle
Ovulation occurswhen the ovary wall ruptures and expels the secondary oocyte
Mittelschmerza twinge of pain sometimes felt at ovulation
After ovulation, the ruptured follicle collapses, granulosa cells enlarge, and along with internal thecal cells, form thecorpus lutetium
The corpus luteum secretesprogesterone and estrogen
If pregnancy does not occur, the corpus luteumdegenerates in 10 days, leaving a scar (corpus albicans)
If pregnancy does occur, the corpus luteumproduces hormones until the placenta takes over that role (at about 3 months)

Hormonal Interactions During the Ovarian Cycle

Question Answer
Day 1GnRH stimulates the release of FSH and LH
FSH and LHstimulate follicle growth and maturation, and low-level estrogen release
Rising estrogen levelsInhibit the release of FSH and LH
Estrogen levels increase and high estrogen levelshave a positive feedback effect on the pituitary, causing a sudden surge of LH
The LH spike stimulates theprimary oocyte to complete meiosis I
The secondary oocyte continues on tometaphase II
Day 14LH triggers ovulation
LH transforms the ruptured follicle intocorpus luteum, which produces inhibin, progesterone, and estrogen
Days 26-28decline of the ovarian hormones ; Ends the blockade of FSH and LH

Menstrual Phase

Question Answer
Days 1-5 Menstrual phase – uterus sheds all but the deepest part of the endometrium
Days 6-14 Proliferative (preovulatory) phase – endometrium rebuilds itself
Days 15-28 Secretory (postovulatory) phase – endometrium prepares for implantation of the embryo
If fertilization does not occur progesterone levels fall, depriving the endometrium of hormonal support
EstrogenPromote oogenesis and follicle growth in the ovary


Question Answer
GonorrheaBacterial infection spread by contact with genital, anal, and pharyngeal mucosal surfaces
SyphilisBacterial infection transmitted sexually or contracted congenitally; A painless chancre appears at the site of infection and disappears in a few weeks
ChlamydiaMost common STD in the U.S.; Symptoms include urethritis; penile and vaginal discharges; abdominal, rectal, or testicular pain; painful intercourse; and irregular menses
Genital wartscaused by human papillomaviruses (HPV); infections increase the risk of penile, vaginal, anal, and cervical cancers