Sl 12 Flashcards
What are the main hormones synthesized and secreted by the testes?
Testosterone and sperm
Testosterone is produced primarily by Leydig cells in the testes.
What are the main hormones synthesized and secreted by the ovaries?
Estrogen and progesterone
Estrogen is predominantly estradiol.
What are the effects of testosterone in males?
Promotes spermatogenesis, development of male secondary sexual characteristics, and influences libido.
How are the testes controlled by gonadotropins?
FSH stimulates Sertoli cells for spermatogenesis, and LH stimulates Leydig cells for testosterone secretion.
What is the effect of anabolic steroid use on the control of the testes?
Leads to negative feedback, reducing endogenous testosterone, testicular size, and sperm counts.
What is the average menstrual cycle duration?
28 days
What changes occur in the uterus during the menstrual phase?
Shedding of the endometrial lining due to low estrogen levels.
What hormonal changes occur during the ovarian cycle?
FSH and LH levels rise and fall, leading to follicle maturation, ovulation, and corpus luteum formation.
What happens during the luteal phase of the ovarian cycle?
Corpus luteum secretes estrogen and progesterone; if no fertilization, it degenerates.
What is menopause?
The cessation of menstruation and hormonal changes that affect physiology in females.
What are the roles of LH and FSH in the ovarian cycle?
- FSH promotes granulosa cell proliferation and estrogen production
- LH stimulates theca cell androgen production.
What is the primary estrogen produced by the ovaries?
Estradiol
What occurs during ovulation?
The follicle ruptures, releasing the oocyte.
What are the effects of estrogen on the endometrium during the proliferative phase?
Endometrial lining begins to reform and thickens.
What is the significance of aromatase in the ovaries?
Catalyzes the conversion of androgens to estrogen.
What is the result of fertilization in terms of hormone production?
Cells at the implantation site produce HCG, preventing corpus luteum degeneration.
What are the effects of progesterone during the secretory phase?
Maintains uterine quiescence and prepares endometrium for potential embryo implantation.
What happens to the corpus luteum if fertilization does not occur?
It degenerates into corpus albicans, leading to decreased estrogen and progesterone.
What is the role of granulosa cells in the ovarian cycle?
Secrete estrogen and inhibin, supporting follicle maturation.
What is the effect of testosterone in target tissues like the prostate?
Converted to dihydrotestosterone (DHT), a more potent form.
Fill in the blank: The primary androgen produced in the testes is _______.
testosterone
True or False: Estrogen and testosterone are unique to males and females, respectively.
False
What is the primary function of Sertoli cells?
Facilitate spermatogenesis.
What causes menstrual cramps during menstruation?
Overproduction of prostaglandins.
During which phase do the dominant follicle and atresia occur?
Early and middle follicular phase.
What happens to FSH and LH levels just before ovulation?
Surge in FSH and LH levels.
What is the fate of preantral and early antral follicles during the menstrual cycle?
They develop into larger follicles or undergo atresia.
What phase occurs between ovulation and the menstrual phase?
Secretory Phase
This phase lasts approximately 10 days.
What structure forms during the secretory phase?
Corpus luteum
What hormones are increased during the secretory phase?
Estrogen and progesterone
What does the endometrium secrete during the secretory phase?
Enzymes, glycogen, and factors necessary to maintain an embryo
What maintains uterine quiescence during the secretory phase?
Presence of progesterone
What happens to the corpus luteum at the end of the secretory phase?
It dies
What are two effects of estrogen during puberty?
- Stimulates fat deposition on hips and breasts
- Stimulates bone growth and closure of the epiphyseal plate
How does estrogen protect against osteoporosis?
By stimulating bone growth
What effect does estrogen have on atherosclerosis?
Protects against it by effects on blood vessels, plasma cholesterol, and blood clotting
What does estrogen cause the cervix to secrete around the time of ovulation?
A clear liquid that helps sperm
What is the main hormone synthesized and secreted by the ovaries?
Estrogen
What are the effects of testosterone in males?
Promotes development of male reproductive tissues and secondary sexual characteristics
What controls the testes?
Gonadotropins
What can disrupt the control of the testes?
Anabolic steroid use
What sequence of events occurs during the ovarian cycle?
Follicular phase, ovulation, luteal phase
What hormonal changes influence the ovarian cycle?
Changes in estrogen and progesterone levels
What are the uterine changes during the follicular phase?
Proliferation of the endometrium
What are the uterine changes during the luteal phase?
Secretion of nutrients and preparation for potential embryo implantation
Define menopause
Cessation of menstrual cycle for more than 12 months
What happens to the follicles during menopause?
They disappear through atresia
What happens to the ovaries’ ability to respond to gonadotropins during menopause?
They lose their ability
What is a consequence of the loss of negative feedback from plasma estrogen?
Increased release of gonadotropins
What is the effect of menopause on estrogen levels?
Persistent small plasma estrogen
What is a risk associated with loss of estrogen’s protective effects?
Increased risk of osteoporosis
What is the controversy surrounding estrogen therapy during menopause?
Increased risk of breast and endometrial cancer
What is andropause?
A male counterpart to menopause with less pronounced hormonal changes
What enzyme converts androgens to estrogens?
Aromatase
What are the two main functions of the ovaries?
- Produce ova
- Secrete hormones (estrogen and progesterone)
What hormone controls the gonads?
Gonadotropin-releasing hormone (GnRH)
What hormones from the anterior pituitary control the gonads?
- Luteinizing hormone (LH)
- Follicle-stimulating hormone (FSH)
What effect does exogenous testosterone have on homeostasis in males?
Disrupts normal hormonal balance affecting testes and spermatogenesis
What is the difference between a follicle and an oocyte?
A follicle is a structure containing an oocyte; an oocyte is the female gamete
What is the significance of the corpus luteum?
It forms after ovulation and releases hormones that maintain uterine events
What must occur for ovulation to take place?
Surge of gonadotropins
How does estrogen affect the hypothalamus during the early/middle follicular phase?
Inhibits GnRH release
What change occurs in estrogen’s effect on the hypothalamus during the late follicular phase?
Estrogen stimulates GnRH release
Why are theca cells necessary for estrogen production in granulosa cells?
They produce androgens that are converted to estrogens by granulosa cells
Describe the sequence of events during the menstrual cycle.
- Menstrual phase
- Proliferative phase
- Secretory phase
If fertilization occurs, what happens to the corpus luteum?
It is maintained by human chorionic gonadotropin (hCG)
Describe two physiological effects of menopause.
- Hot flashes
- Vaginal dryness
