Physiology Lecture 25
44 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

The presence of testes promotes the development of female reproductive structures.

False

What do Leydig cells produce that contributes to the development of male genitalia?

Testosterone

In females, the __________ ducts develop into female reproductive structures.

Müllerian

What hormone does Sertoli cells produce to inhibit female reproductive structure development?

<p>Anti-Müllerian hormone (AMH)</p> Signup and view all the answers

Match the following ducts with their outcomes in males and females:

<p>Wolffian ducts = Regress in females Müllerian ducts = Develop into female reproductive structures</p> Signup and view all the answers

Testosterone is converted from progesterone by the enzyme CYP17.

<p>True</p> Signup and view all the answers

What happens to the Müllerian ducts in the presence of testosterone?

<p>They regress</p> Signup and view all the answers

What is the primary function of Leydig cells in the testes?

<p>Release testosterone</p> Signup and view all the answers

The fallopian tubes are responsible for transporting sperm from the ovaries to the uterus.

<p>False</p> Signup and view all the answers

What hormone is primarily involved in the development and maturation of ova in the ovaries?

<p>Estrogen</p> Signup and view all the answers

The __________ is where sperm gain motility after being produced.

<p>epididymis</p> Signup and view all the answers

Match the following male reproductive structures with their functions:

<p>Epididymis = Where sperm gain motility Vas deferens = Conduit for sperm during ejaculation Seminal vesicles = Produce alkaline fluid for sperm nourishment Prostate gland = Contributes enzymes to liquefy semen</p> Signup and view all the answers

What is the role of granulosa cells in the ovaries?

<p>Support egg development and release estrogen</p> Signup and view all the answers

The uterus is a muscular organ where fertilization occurs.

<p>False</p> Signup and view all the answers

Which hormone is secreted by Sertoli cells to support germ cell development?

<p>Inhibin</p> Signup and view all the answers

What is the primary function of estrogen in males?

<p>Spermatogenesis</p> Signup and view all the answers

Estrogen in females is primarily produced by peripheral tissues.

<p>False</p> Signup and view all the answers

Which enzyme is responsible for converting testosterone into estrogen?

<p>Aromatase</p> Signup and view all the answers

In males, circulating estrogen is produced in the __________ tissue.

<p>peripheral</p> Signup and view all the answers

Match the following cells with their functions:

<p>Leydig cells = Produce testosterone and progesterone Sertoli cells = Support germ cell development and produce inhibin Granulosa cells = Convert androgen to estrogen in females Theca cells = Produce androgens in females</p> Signup and view all the answers

What triggers the start of puberty?

<p>Increased levels of gonadotropins</p> Signup and view all the answers

An estrogen deficiency can lead to osteoporosis.

<p>True</p> Signup and view all the answers

What hormone do Sertoli cells produce to control FSH release?

<p>Inhibin</p> Signup and view all the answers

What is the typical time duration of GnRH release in each pulse?

<p>5–25 minutes</p> Signup and view all the answers

The pulsatile release of GnRH results in decreased hormone signaling.

<p>False</p> Signup and view all the answers

What hormones are stimulated by GnRH?

<p>FSH and LH</p> Signup and view all the answers

Inhibin, produced by Sertoli cells, specifically reduces ______ secretion from the anterior pituitary.

<p>FSH</p> Signup and view all the answers

What is the effect of estrogen and progesterone on the hypothalamus and anterior pituitary in females?

<p>Negative feedback</p> Signup and view all the answers

Match the hormones with their respective feedback mechanism:

<p>Estrogen = Negative feedback in most circumstances Progesterone = Negative feedback on GnRH Testosterone = Suppresses GnRH and LH secretion High Estrogen = Positive feedback leading to LH surge</p> Signup and view all the answers

Which hormone's secretion best matches the pulsatile pattern of GnRH?

<p>LH</p> Signup and view all the answers

What triggers ovulation in females?

<p>Surge of LH and FSH</p> Signup and view all the answers

What is the main hormone responsible for triggering ovulation?

<p>LH</p> Signup and view all the answers

The luteal phase is dominated by estrogen production.

<p>False</p> Signup and view all the answers

What happens to theca and granulosa cells after ovulation?

<p>They undergo luteinization, transforming into luteal cells.</p> Signup and view all the answers

The ________ phase of the ovarian cycle occurs from Day 1 to 14.

<p>Follicular</p> Signup and view all the answers

Which hormone is primarily responsible for maintaining the endometrium during the luteal phase?

<p>Progesterone</p> Signup and view all the answers

Match the following phases with their corresponding characteristics:

<p>Follicular phase = Dominated by FSH and estrogen Ovulation phase = Triggered by LH surge Luteal phase = Dominated by progesterone Proliferative phase = Endometrium thickening due to estrogen</p> Signup and view all the answers

If fertilization does not occur, progesterone levels decrease, leading to menstruation.

<p>True</p> Signup and view all the answers

Cervical mucus becomes abundant, thin, watery, and ________ during the proliferative phase.

<p>alkaline</p> Signup and view all the answers

What predominates during the secretory phase of the menstrual cycle?

<p>Progesterone</p> Signup and view all the answers

During the menstrual phase, estrogen levels decline, leading to the shedding of the endometrial lining.

<p>True</p> Signup and view all the answers

What effect does progesterone have on cervical mucus during the secretory phase?

<p>It becomes viscous and acidic.</p> Signup and view all the answers

The release of ______ causes vasoconstriction in the uterus during the menstrual phase.

<p>Prostaglandins</p> Signup and view all the answers

Match the phases of the menstrual cycle with their definitions:

<p>Secretory phase = Endometrial lining preparation for implantation Menstrual phase = Shedding of the endometrial lining Follicular phase = Development of follicles in the ovaries Ovulation = Release of an egg from the ovary</p> Signup and view all the answers

Study Notes

Puberty and Reproductive Years

  • Puberty establishes functional and structural maturation through the hypothalamic-pituitary-gonadal axis.
  • Sex hormones control synthesis and mechanisms.
  • Menstrual cycles are a key aspect of this process.

Gonadal Sex: Testes

  • Germ cells produce sperm.
  • Leydig cells release testosterone.
  • Sertoli cells support germ cell development and release inhibin.

Gonadal Sex: Ovaries

  • Germ cells produce eggs (ova).
  • Granulosa cells support egg development and release estrogen.
  • Theca cells produce androgens, precursors to estrogen.

Hormone Function in Testes

  • Supporting sperm maturation, testosterone synthesis, and secretion of anti-Müllerian hormone.

Hormone Function in Ovaries

  • Development and maturation of ova.
  • Synthesis and secretion of estrogen and progesterone.

Male Genitalia

  • The epididymis is where sperm mature and gain motility.
  • The vas deferens propels sperm during ejaculation.

Female Genitalia

  • Fallopian tubes transport ova from ovaries to uterus; site of fertilization.
  • Uterus is a muscular organ where fertilized eggs implant and develop into fetuses.
  • Upper one-third of the vagina is part of the birth canal and involved in sexual reproduction.

Male External Genitalia

  • Penis is involved in sexual intercourse and urination.
  • Scrotum houses and protects testes, regulating temperature for sperm production.

Female External Genitalia

  • Clitoris is a sensitive organ for sexual pleasure.
  • Labia majora are outer folds of skin protecting vaginal opening.
  • Labia minora are inner folds surrounding the vestibule and clitoris.
  • Lower two-thirds of the vagina is the external part, involved in intercourse and childbirth.

Y Chromosome

  • Determines male gonadal and phenotypic sex.
  • Contains the testis-determining gene.
  • Presence of the Y chromosome differentiates male phenotype.

Factors Influencing Sex Differentiation

  • Testes presence drives male phenotype differentiation.

  • Sertoli cells produce AMH, inhibiting development of female reproductive structures.

  • Leydig cells produce testosterone promoting the development of male genitalia.

Female Phenotype Differentiation

  • Independent of ovary presence.
  • Dependent on absence of testes and corresponding hormones.
  • Sex duct system develops differently in females than males.

Sex Hormone Production and Conversion

  • Progesterone is converted into testosterone by CYP17 enzyme (17a-hydroxylase/17,20 lyase).
  • Testosterone is converted into estrogen by aromatase.
  • Testosterone is converted into DHT by 5α-reductase.

Male vs. Female Estrogen

  • In males, testicular aromatase-induced estrogen is primarily involved in spermatogenesis.
  • In females, estrogen is primarily released from the ovaries.

Aromatase Enzyme

  • Found in gonads, skin, adipose tissue, blood vessels, and muscles.
  • Converts testosterone into the potent estrogen 17β-estradiol (E2).

Androgenic Effects

  • Circulating estrogen affects males and females.
  • Influences peripheral tissues in males and ovaries in females.
  • Important role in skeletal health, with estrogen promoting osteoblast survival and inhibiting osteoclasts.

Testosterone Physiological Functions

  • Responsible for male phenotype, spermatogenesis, and all androgenic responses during fetal development.

Sertoli Cell Functions

  • Produces anti-Müllerian hormone for male phenotype development in the embryo.

GnRH (Gonadotropin-Releasing Hormone)

  • Initiates puberty, predominantly released in pulsatile manner during sleep.
  • Its release pattern (5–25 minutes every 60–90 minutes) is crucial for receptor replenishment and effective hormone signaling.
  • Stimulates FSH (follicle-stimulating hormone) and LH (luteinizing hormone) secretion.

LH (Luteinizing Hormone)

  • Secretion best matches pulsatile pattern of GnRH.
  • Plays key role during puberty in stimulating sex hormone production and secretion.

Sex Hormone Regulation: Feedback

  • Testosterone reaches desired levels, suppressing GnRH secretion and anterior pituitary LH release.
  • Negative feedback mechanisms regulate hormone production and secretion.

Inhibin and LH Receptors

  • Inhibin produced by Sertoli cells reduces anterior pituitary FSH secretion.
  • Theca and granulosa cells contain LH receptors.

Progesterone and Androgen Production

  • Androgens from Theca cells diffuse to Granulosa cells.

  • FSH stimulates aromatase conversion into estrogens.

  • Released into bloodstream in both males and females.

Negative Feedback in Females

  • Progesterone and estrogen provide negative feedback on hypothalamus and anterior pituitary.

Female Positive Feedback

  • High estrogen levels activate positive feedback on hypothalamus and anterior pituitary, surge of LH and FSH.
  • Granulosa cells release activin to enhance FSH production, triggering ovulation.

Ovarian Cycle Phases

  • Follicular Phase (Days 1-14): FSH and estrogen dominate, follicle growth, and endometrium preparation.
  • Ovulation (Day 14): Surge in LH triggers oocyte release.
  • Luteal Phase (Days 14-28): Progesterone dominates, preparing for possible implantation.

LH Surge and Ovulation

  • LH surge is necessary for ovulation.
  • Estrogen feedback, initially negative, becomes positive before ovulation.

Post-Ovulation Changes in Theca and Granulosa Cells

  • Theca and granulosa cells luteinize, converting to luteal cells.
  • Corpus luteum formation secretes progesterone and estrogen.

Luteal Phase Estrogen/Progesterone Difference

  • Lack of CYP17 enzyme for converting progesterone to estrogen.
  • Increased inhibin, limiting FSH and estrogen stimulation, leads to higher progesterone relative to estrogen during the luteal phase.

No Fertilization

  • If no fertilization, progesterone and estrogen decline.
  • Negative feedback is lifted, increasing FSH and LH, stimulating new follicle development.
  • Endometrium sheds (menstruation).

Uterus Cycle Phases

  • Proliferative Phase: Estrogen causes endometrial thickening, favorable environment for sperm.
  • Secretory Phase: Progesterone thickens endometrial lining preparation for possible implantation.

Additional factors

  • Cervical mucus becomes viscous and acidic, creating less favorable environment for sperm.
  • Prostaglandins (PGs) are released, initiate shedding of the endometrium, and cause vasodilation during menstruation.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Physiology Lecture 25 PDF

Description

This quiz explores key concepts related to male and female reproductive systems. Questions cover the functions of various reproductive organs, hormones, and processes involved in sexual development and reproduction. Test your knowledge on the roles of Leydig and Sertoli cells, as well as the development of reproductive structures.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser