Lecture Finals pt.1

Male Reproductive System

• The male gonads are the testes (singular: testis).

Sperm Production

• Sperm is produced in the seminiferous tubules of the testes.

Spermatogenesis

• Diploid cells in spermatogenesis: Spermatogonia and primary spermatocytes.
• Haploid cells in spermatogenesis: Secondary spermatocytes, spermatids, and mature sperm (spermatozoa).
• The first haploid cells in spermatogenesis are called secondary spermatocytes.

Acrosome

• An acrosome is a cap-like structure on the head of a sperm cell, containing enzymes that help the sperm penetrate the outer layers of the egg (oocyte) during fertilization.

Testosterone

• Leydig cells (interstitial cells) produce testosterone.
• The function of testosterone is to:
  • Stimulate the development of male secondary sexual characteristics.
  • Support spermatogenesis.
  • Influence libido.

Male Reproductive System

• The male gonads are the testes (singular: testis).

Spermatogenesis

• Haploid cells in spermatogenesis include: secondary spermatocytes, spermatids, and mature sperm (spermatozoa).

Sperm Cell Structure

• An acrosome is an enzyme-filled cap-like structure found on the head of a sperm cell.

Testosterone Function

• Testosterone stimulates the development of male secondary sexual characteristics.
• Testosterone supports spermatogenesis.
• Testosterone influences libido.

Male Reproductive System

• Male gonads: Testes
• Male gametes: Sperm

Female Reproductive System

• Female gonads: Ovaries
• Female gametes: Ova (eggs)

Cell Types in the Testes

• Three types of cells found in the testes: Spermatogenic cells, Leydig (interstitial) cells, and Sertoli cells
• Spermatogenic cells: produce sperm
• Leydig (interstitial) cells: produce testosterone
• Sertoli cells: support, nourish, and regulate the spermatogenic cells
• Sertoli cell is often referred to as the "nurse" cell

Reproductive System

• Female gonads are called ovaries.
• Female gametes are called ova (eggs).
• Interstitial cells, also known as Leydig cells, produce testosterone.

Sperm Cell Development

• Spermatogonia develops into primary spermatocyte
• Primary spermatocyte develops into secondary spermatocyte
• Secondary spermatocyte develops into spermatid
• Spermatid develops into mature sperm (spermatozoa)

Processes of Sperm Production

• Mitosis: occurrence of cell division
• Meiosis: reduction of chromosome number from diploid to haploid
• Spermiogenesis: development of spermatid into mature sperm

Sperm Production and Transportation

• Sperm is produced in the seminiferous tubules of the testes
• Sperm is stored and matured in the epididymis
• Sperm is transported through the vas deferens

Seminal Vesicles

• Produce a fluid rich in fructose that nourishes sperm
• Contribute to the formation of a major component of semen

Sperm Transportation and Production

• Sperm is transported through the vas deferens.
• Sperm is produced in the seminiferous tubules of the testes.

Glands and Their Functions

• The prostate gland produces a fluid that helps to activate sperm.
• The bulbourethral glands produce a pre-ejaculate fluid that:
  • Lubricates the urethra for sperm to pass through.
  • Helps to neutralize acidity in the urethra.

Composition of Semen

• Fructose is present in semen and provides energy for sperm motility.

Reproductive Processes

• Prostaglandins in semen help thin the mucus in the cervix, allowing sperm to move into the uterus.
• The parasympathetic branch of the autonomic nervous system is responsible for causing erection.

Ejaculation

• Ejaculation is caused by the sympathetic nervous system's activation, leading to muscular contractions that propel semen through the urethra and out of the body.

Hormone Regulation

• Once the desired level of testosterone is achieved, it sends a negative message back to the hypothalamus and the anterior pituitary gland.
• Testosterone inhibits the production of Luteinizing hormone (LH) and Follicle-stimulating hormone (FSH) through negative feedback.

Female Reproductive System

• The female gonads are the ovaries.

Hormones Produced in Ovaries and Testes

• Ovaries produce estrogen and progesterone
• Testes produce testosterone

Hormonal Regulation of Testes and Ovaries

• The hypothalamus releases GnRH, stimulating the anterior pituitary to release LH and FSH

Hormonal Regulation of Testes (Males)

• LH stimulates testosterone production from Leydig cells
• FSH supports spermatogenesis

Hormonal Regulation of Ovaries (Females)

• LH and FSH regulate the menstrual cycle
• LH triggers ovulation
• FSH stimulates follicular growth

Phases of the Ovarian Cycle

• Follicular phase: characterized by the growth and maturation of ovarian follicles under the influence of FSH
• Ovulation
• Luteal phase

Phases of the Ovarian Cycle

• The ovarian cycle consists of three phases: follicular phase, ovulation, and luteal phase.

Hormonal Regulation of the Testes

• LH (luteinizing hormone) stimulates testosterone production from Leydig cells in the testes.
• FSH (follicle-stimulating hormone) supports spermatogenesis in the testes.

Hormonal Regulation of the Ovaries

• LH and FSH regulate the menstrual cycle in females.
• LH triggers ovulation in females.
• FSH stimulates follicular growth in females.

Hormones Produced in the Testes

• Testes produce testosterone.

Hormonal Regulation of the Testes

• LH (Luteinizing Hormone) stimulates the production of testosterone from Leydig cells in the testes.
• FSH (Follicle-Stimulating Hormone) plays a crucial role in supporting spermatogenesis, the process of sperm cell development.

Ovarian Cycle

• Follicular phase is regulated by Follicle-stimulating hormone (FSH)
• Ovulation occurs on Day 14 of the ovarian cycle, releasing a mature egg from the ovary
• Luteinizing hormone (LH) triggers ovulation

Post-Ovulation

• After ovulation, the ruptured follicle transforms into the corpus luteum
• Corpus luteum secretes progesterone and estrogen to prepare the endometrium for potential pregnancy
• Hormones secreted from the corpus luteum include progesterone and estrogen

Fate of Corpus Luteum

• If fertilization does not occur, the corpus luteum degenerates into the corpus albicans
• Decrease in progesterone and estrogen triggers menstruation
• If fertilization occurs, the corpus luteum continues to produce progesterone and estrogen to support early pregnancy
• The placenta eventually takes over hormone production from the corpus luteum

Corpus Luteum

• If fertilization does not occur, the corpus luteum degenerates into the corpus albicans.
• This degeneration leads to a decrease in progesterone and estrogen levels.

Hormones of Corpus Luteum

• The corpus luteum secretes two main hormones: progesterone and estrogen.

Meiosis

• Meiosis II is completed upon fertilization, resulting in the division of the secondary oocyte into the ovum and a second polar body.
• The product of oogenesis is one ovum (egg) and polar bodies.

Cell Division

• Mitosis occurs during embryonic development, growth, and tissue repair.
• Meiosis occurs during the formation of gametes (sperm in males and eggs in females).

Female Reproductive System

• The uterine tubes transport the ovum from the ovary to the uterus, which is the site of fertilization.
• Fertilization typically occurs in the ampulla of the uterine tube.
• The fimbria sweeps the ovum into the uterine tube following ovulation.

Uterine Cycle

• The uterine cycle consists of the menstrual phase, proliferative phase, and secretory phase, regulated by changes in hormone levels.
• The three layers of the uterus are the perimetrium (outer layer), myometrium (middle muscular layer), and endometrium (inner lining).
• Shedding occurs in the endometrium during menstruation, which is maintained by estrogen and progesterone hormones.

Cell Division and Reproduction

• Mitosis occurs during embryonic development, growth, and tissue repair.
• Meiosis occurs during the formation of gametes (sperm in males and eggs in females).

Female Reproductive System

• The uterine tubes transport the ovum from the ovary to the uterus, where fertilization takes place.
• Meiosis II is completed upon fertilization, resulting in the division of the secondary oocyte into the ovum and a second polar body.

Uterine Cycle

• The uterine cycle consists of three phases: menstrual, proliferative, and secretory.
• The cycle is regulated by changes in hormone levels.
• Shedding occurs in the endometrium during the menstrual phase.

Mitosis Occurrence

• Takes place during embryonic development, a crucial stage where cells multiply and differentiate to form tissues and organs.
• Occurs during growth, allowing the organism to increase in size and complexity.
• Essential for tissue repair, as it enables the replacement of damaged or dead cells with new ones.

Meiosis

• Cross-over and synapses occur during Prophase I of meiosis.

Hormones and Their Functions

GnRH

• Stimulates the anterior pituitary to release FSH and LH.
• Secreted from the hypothalamus.

FSH

• Stimulates the growth of ovarian follicles in females.
• Stimulates spermatogenesis in males.
• Secreted from the anterior pituitary gland.

LH

• Triggers ovulation in females.
• Triggers testosterone production in males.
• Secreted from the anterior pituitary gland.

Hormone Secretion

• FSH (Follicle-Stimulating Hormone) and LH (Luteinizing Hormone) are secreted from the anterior pituitary gland.

Estrogen Function

• Estrogen regulates the menstrual cycle.
• Estrogen promotes the development of female secondary sexual characteristics.
• Estrogen supports pregnancy.

Estrogen Secretion

• Estrogen is secreted mainly by the ovaries.

Oocyte Development

• At birth, primary oocytes are arrested in Prophase I of meiosis.
• During puberty, some primary oocytes complete meiosis I to become secondary oocytes each month.
• After fertilization, the secondary oocyte completes meiosis II to become an ovum.

Oocyte Development

• During puberty, a selection of primary oocytes advances to the next stage of development by completing meiosis I.
• As a result, these primary oocytes transform into secondary oocytes on a monthly basis.
• Following fertilization, the secondary oocyte undergoes further development by completing meiosis II.
• The culmination of meiosis II is the formation of a mature ovum.

Oogenesis

• Meiosis I is the type of cell division that occurs when a primary oocyte divides to become a secondary oocyte.
• During ovulation, a secondary oocyte is released, which is paused in Metaphase II of meiosis.

Completion of Meiosis I

• One secondary oocyte and one polar body are produced at the completion of meiosis I.

Completion of Meiosis II

• One ovum (mature egg) and a second polar body are produced at the completion of meiosis II.

Cell Division and Ovulation

• Meiosis I is the type of cell division that occurs when the primary oocyte divides to become a secondary oocyte.
• After ovulation, the tissue that surrounds the oocyte transforms into the corpus luteum.

Corpus Luteum and Hormones

• The corpus luteum is a temporary endocrine structure that secretes progesterone and estrogen.
• Estrogen is responsible for the thickening of the uterine lining during the proliferative phase.
• Progesterone is responsible for the thickening of the uterine lining during the secretory phase.

Menstrual Cycle Phases

• Menarche is the first menstrual cycle or first menstrual bleeding in female humans.
• Menses refers to the monthly uterine bleeding in the menstrual cycle.
• Menses is the phase of the menstrual cycle where the uterine lining is shed, resulting in menstrual bleeding.
• Menses typically occurs on days 1-5 of the menstrual cycle.

Ovulation and Proliferative Phase

• Rising levels of LH (Luteinizing hormone) stimulate ovulation.
• Ovulation typically occurs on day 14 of a 28-day cycle.
• The proliferative phase occurs approximately on days 6-14 of the menstrual cycle, ending with ovulation.

Cell Division and Ovulation

• Meiosis I is the type of cell division that occurs when the primary oocyte divides to become a secondary oocyte.
• After ovulation, the tissue that surrounds the oocyte transforms into the corpus luteum.

Corpus Luteum and Hormones

• The corpus luteum is a temporary endocrine structure that secretes progesterone and estrogen.
• Estrogen is responsible for the thickening of the uterine lining during the proliferative phase.
• Progesterone is responsible for the thickening of the uterine lining during the secretory phase.

Menstrual Cycle Phases

• Menarche is the first menstrual cycle or first menstrual bleeding in female humans.
• Menses refers to the monthly uterine bleeding in the menstrual cycle.
• Menses is the phase of the menstrual cycle where the uterine lining is shed, resulting in menstrual bleeding.
• Menses typically occurs on days 1-5 of the menstrual cycle.

Ovulation and Proliferative Phase

• Rising levels of LH (Luteinizing hormone) stimulate ovulation.
• Ovulation typically occurs on day 14 of a 28-day cycle.
• The proliferative phase occurs approximately on days 6-14 of the menstrual cycle, ending with ovulation.

Cell Division and Ovulation

• Meiosis I is the type of cell division that occurs when the primary oocyte divides to become a secondary oocyte.
• After ovulation, the tissue that surrounds the oocyte transforms into the corpus luteum.

Corpus Luteum and Hormones

• The corpus luteum is a temporary endocrine structure that secretes progesterone and estrogen.
• Estrogen is responsible for the thickening of the uterine lining during the proliferative phase.
• Progesterone is responsible for the thickening of the uterine lining during the secretory phase.

Menstrual Cycle Phases

• Menarche is the first menstrual cycle or first menstrual bleeding in female humans.
• Menses refers to the monthly uterine bleeding in the menstrual cycle.
• Menses is the phase of the menstrual cycle where the uterine lining is shed, resulting in menstrual bleeding.
• Menses typically occurs on days 1-5 of the menstrual cycle.

Ovulation and Proliferative Phase

• Rising levels of LH (Luteinizing hormone) stimulate ovulation.
• Ovulation typically occurs on day 14 of a 28-day cycle.
• The proliferative phase occurs approximately on days 6-14 of the menstrual cycle, ending with ovulation.