Male Reproductive System

Male Reproductive System

• Testes relate to gonads, as sperm relates to gametes
• Sperm production happens in Seminiferous tubules, located within the testis
• Sperm travel in the epididymis towards the ductus deferens
• The ejaculatory duct travels through the prostate gland
• Serosa is not a region of the male urethra
• Prepuce is also known as the foreskin
• Seminal vesicle is a male accessory sex gland, which produces a yellowish secretion containing fructose, prostaglandins, coagulating proteins, and enzymes.
• The enlargement of the prostate gland cause constriction the ejaculatory duct
• Clotting proteins are compounds allowing semen to temporarily coagulate after ejaculation.
• Semen is expelled from the body during ejaculation
• Contraction of the cremaster muscle pulls the testes closer to the body
• Spermatogenesis involves the development of male gametes or sperm cells
• Spermatogonium is the stem cell that begins spermatogenesis
• Four spermatids result from one spermatogonium
• Spermiogenesis begins with a spermatid and ends with a sperm
• Damage sustained to the sustentacular cells of the testes impairs spermatogenesis
• Maturation in which spermatids elongate and shed excess cytoplasm leads to spermiogenesis
• Testosterone is the main hormone regulating spermatogenesis
• Luteinizing hormone (LH) stimulates interstitial cells of the testes to produce testosterone
• Inhibin decreases the release of follicle-stimulating hormone (FSH) in males
• Excess testosterone inhibits the production of gonadotropin-releasing hormone (GnRH)
• Emission involves movement of sperm, testicular fluids, and secretions from the prostate gland and seminal vesicle into the urethra.
• Erection is under control of the parasympathetic nervous system
• Impotence affects people that are unable to maintain an erection
• Spermatogenesis begins at puberty for males

Effects of Testosterone

• Testosterone does NOT increase libido
• Anabolic effects of testosterone include:
  • Increased number of erythrocytes
  • Increased skeletal muscle mass
  • Increased bone density

Andropause

• Decline in male reproductive functions

Enlarged Prostate

• Can cause difficulty urinating, which can be linked with the enlarged prostate gland.

Ovaries

• Ovaries are the main female gonad
• Ovarian ligament anchors the ovary to the uterus
• Fertilization usually takes place in the ampulla of the uterine tube
• A fertilized ovum should implant in the uterus
• The Cervix is the most inferior portion of the uterus
• The Myometrium portion of the uterus is composed of smooth muscle and contracts rhythmically during orgasm and childbirth.
• Vagina receives the penis during sexual intercourse
• Douching washes away beneficial bacteria and alters the pH balance of the vagina
• Vagina is NOT part of the female's external genitalia in females
• Blockage to the mammary ducts of the mammary gland prevents the passage of milk
• Alveoli are not present in a non-lactating female
• Oogonia are formed before birth in females
• Secondary oocyte can be fertilized
• Vesicular (tertiary) follicle contains a secondary oocyte arrested in metaphase II
• Follicular phase is the first phase of the ovarian cycle
• Ovulation should occur on day 14 of a 28-day ovarian cycle
• Ovaries are the target by Follicle-stimulating hormone(FSH) and luteinizing hormone(LH) in females
• Ovulation is triggered by a surge in luteinizing hormone (LH)
• Women that want to become pregnant should have sexual intercourse after a surge in luteinizing hormone (LH)
• Ovulation is regulated by a positive feedback mechanism in females
• Estrogens are critical for adipose tissue deposits in the breasts, hips, and thighs in females
• Stratum functionalis of the endometrium gets shed during menstruation
• Proliferative (preovulatory) phase will develop stratum functionalis with endometrial glands and spiral arteries and veins
• Menarche occurs during puberty
• Menstruation has ceased for at least one year during the female climacteric, or menopause

Birth Control Methods

• Condoms are an alternative birth control method, if a couple want to have sexual intercourse, and they do not wish to use a behavior method
• Intramuscular injections of the Depo-Provera shot has progesterone only
• Hormonal method is a time of birth controls that prevent pregnancy by manipulating the hormones and interfering with ovulation

STI (Sexually Transmitted Infections)

• Genital herpes is not a bacterial sexually transmitted infection (STI)
• Syphilis is the sexually transmitted infection (STI) a male patient has contracted, with a pink rash all over the body, a fever, joint pain, and some hair loss
• Trichomoniasis is caused by parasite
• Human papillomavirus (HPV) is linked with many cases of cervical cancer
• Trichomoniasis has symptoms that include a greenish-white discharge from the vagina that has a strong odor, itching and burning of the genitals
• Human papillomavirus (HPV) can be prevented with a vaccine

Important Facts

• A cell with 12 pairs of homologous chromosomes is said to be diploid, 2n
• From one original cell, four genetically unique daughter cells, each with 23 nonreplicated chromosomes, are produced at the conclusion of meiosis II of spermatogenesis.
• Testosterone is made by the myoid cells of the male testes - FALSE
• During an erection, blood from the testicular arteries fills the vascular spaces of the corpus spongiosum of the penis - FALSE
• The prostate gland releases clotting proteins into ejaculated semen which cause coagulation and temporarily prevents the sperm from leaking back out of the female reproductive tract- TRUE
• During cold temperatures, the testes are pulled closer to the pelvic floor and the warmth of the body wall, and the scrotum becomes shorter and heavily wrinkled- TRUE
• Spermiogenesis is the process of sperm cell development. It includes all phases of meiosis and spermatogenesis, the cytoplasmic changes required to form a mature sperm cell- FALSE
• High levels of testosterone inhibit gonadotropin-releasing hormone (GnRH) by the hypothalamus- TRUE
• The round ligaments connect each ovary to the uterus and receive an oocyte during ovulation- FALSE
• The uterus is anchored by the broad ligament, suspensory ligament, and the round ligament- FALSE
• During the luteal phase of the uterine (menstrual) cycle, the corpus luteum secretes progesterone and some estrogen- FALSE
• If pregnancy occurs, the secretory phase of the uterine (menstrual) cycle continues and the uterus will continue to develop- TRUE
• The high levels of estrogens during the luteal phase of the ovarian cycle trigger release of more FSH and LH, and their levels peak around day 14, which causes ovulation- FALSE
• Barrier methods of birth control prevent sperm from moving beyond the vagina and include condoms, diaphragms, cervical caps, and the sponge- TRUE
• The common viral sexually transmitted infections (STIs) are chlamydia, gonorrhea, syphilis, and trichomoniasis- FALSE

Organs of the Male Reproductive System

• Epididymis is labeled with G
• Ejaculatory duct is labeled with E
• Ductus deferens is labeled with D
• Prostate gland is labeled B

Organs of the Female Reproductive System

• Round ligament is labeled with D
• Ovary is labeled with C
• Uterine tube is labeled with B

Phases of the Uterine Cycle

• The uterus sheds the stratum functionalis of the endometrium during phase A
• The endometrium prepares for implantation of an embryo by continuing to grow, increasing vasculature, and secreting nutrients into the uterine cavity during phase C
• a surge in luteinizing hormone (LH) occurs during the ovarian cycle and relates to phase B
• Cervical mucus thins on this day to facilitate the passage of sperm into the uterus during phase C

Chromosomes

• Homologous chromosomes are pairs of chromosomes with the same genes, however, the matching genes on the homologous chromosomes may have different variants, or alleles.

Meiosis

• Important points about meiosis I include pairs of homologous chromosomes, each consisting of two sister chromatids that separate to produce haploid (1n) cells with 23 chromosomes.
  • Crossing over and independent assortment randomly "shuffle" the alleles and align the maternal and paternal chromosomes, contributing to genetic diversity of the offspring.
• Important points about meiosis II is the process separates the homologous chromosomes into individual chromatids resulting in four haploid cells

Mitosis vs Meiosis

• Mitosis is needed for tissue growth or repair
  • new cells must be genetically identical to the original cell.
  • Mitosis makes a complete copy of the DNA and dividing each cell into two resulting cells that get one copy of the DNA.
• Meiosis produces sperm and ova for reproduction that need to have half the chromosome number of the original cell to combine to form a new cell, so the chromosome number will not be doubled - Meiosis mixes up the possible combinations of genes that each sperm or egg cell will receive, to produce a genetically unique individual. - Meiosis I reduces the chromosome number and shuffle the alleles - Meiosis II then completes the process to potentially form four daughter cells.

Sperm Pathway

• Sperm are made in the seminiferous tubules of each testis.
  • Seminiferous tubules are surrounded by myoid cells, which contract to push sperm and testicular fluids through the tubules and out of the testes.
  • Seminiferous tubules of each lobule merge into a single straight tubule that moves sperm into the rete testis, which is a network of tubules on the posterior side of the testis.
  • Sperm then pass through efferent ductules and enter the first portion of the duct system, the epididymis.
  • After leaving the epididymis, the sperm continue traveling through a system of ducts, the ductus deferens, ejaculatory duct, urethra (prostatic, membranous and spongy regions) and exit the body through the external urethral orifice.

Sperm Capacitation

• Prevents sperm from fertilizing an immature female gamete.
• Helps sperm become fully motile, which enables them to penetrate and fertilize an immature female gamete.
• Prepares the sperm cell's plasma membrane to fuse with that of the female gamete

Spermatogenesis and Spermiogenesis

• Spermatogenesis is the process of sperm cell development including meiosis and spermiogenesis (maturation of spermatids into motile sperm cells)
• Spermatogenesis occurs in the seminiferous tubules of the testes by spermatogenic cells, where Spermatogonia divide to produce primary spermatocytes, which undergo the first meiotic division to form two secondary spermatocytes.
• Secondary spermatocytes undergo the second meiotic division to produce four total spermatids

Hypothalamic-Pituitary-Gonadal (HPG) Axis

• Hypothalamus releases gonadotropin-releasing hormone (GnRH)
• GnRH stimulates the anterior pituitary to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
• LH stimulates the interstitial cells of the testes to secrete testosterone while FSH stimulates the sustentacular cells to secrete androgen-binding protein (ABP), which helps keep testosterone levels high) and the hormone inhibin

Male Sexual Response and Ejaculation

• Erection is under parasympathetic control.
• Ejaculation is under sympathetic control.
• Sexual arousal triggers a parasympathetic reflex and the release of nitric oxide (NO) from blood vessel endothelial cells.
• Smooth muscle relaxes in the walls of the arterioles of the penis, dilating them, and within the blood sinuses in erectile tissue and allowing large amounts of blood to enter the tissue. The result in increased blood flow and widening blood sinuses causes an erection
• Ejaculation stages include emission and expulsion:
  • Emission is the movement of sperm and testicular fluid, as well as secretions from the prostate gland and seminal vesicle, into the urethra.
  • Rhythmic contractions stem from skeletal muscles at the base of the erectile columns of the penis result in the expulsion of semen from the urethra

Ovaries Functions

• Produce ova
• Secrete: estrogens, progesterone, inhibin, and relaxin

Ovary Support

• Broad ligament: connects the ovaries, uterine tubes, and uterus and connects ovary to the bony pelvis
• Ovarian ligament: connects the medial surface of the ovary to the uterus, near the attachment of the uterine tube
• Suspensory ligament: connects the lateral surface of the ovary to the pelvic wall

Uterus Layers

• Perimetrium: the outermost serous layer of the uterus
• Myometrium: the thick middle layer, composed of bundles of smooth muscle
• Endometrium: the innermost mucous membrane composed of simple columnar epithelium on a layer of connective tissue called the lamina propria

Ooctye Pathway

• From the ovary, the oocyte travels into the uterine tube where the fimbriae sweep the ovarian surface and "catch" the oocyte. -The oocyte moves through the infundibulum, ampulla, and the isthmus of the uterine tube, and then enters the uterus.

Ovarian Cycle Phases

Follicular phase

• Primary follicles (with primary oocytes) begin to mature into secondary follicles.
• One secondary follicle with a primary oocyte develops into a vesicular (tertiary) follicle and the primary oocyte inside becomes a secondary oocyte after the LH surge.

Ovulation

Releases secondary oocyte into peritoneal cavity

Luteal phase

ruptured follicle forms the corpus luteum, which secretes progesterone and estrogens. If fertilization does not occur, the corpus luteum degenerates into the corpus albicans

Progesterone

• With fertility: the corpus luteum inhibits the release of gonadotropins
• Without fertility: the corpus luteum degenerates into the corpus albicans and estrogen, progesterone, and inhibin levels drop and ovarian hormones no longer inhibit secretion of GnRH, so its levels rise the cycle begins again.

Female Sex Characteristics

• Female secondary sex characteristics: changes in bone structure (widening pelvis), increase in adipose tissue (breasts and hips and thighs), hair in the pubic and axillary areas, and development of female libido

Uterine (menstrual) Cycle

• Uterine cycle: cyclic changes in the endometrium in response to fluctuating ovarian hormones. In order:

Menstrual phase

• the uterus sheds the stratum functionalis of the endometrium through the vagina
• Rising Follicle stimulating hormone(FSH) and luteinizing hormone(LH) levels and normal/low levels of estrogens and progesterone

Proliferative phase

• New stratum functionalis grows and thickens as estrogen levels rise
• Ovulation at the end of this phase

Secretory phase

• the endometrium prepares for implantation of an embryo by continuing to grow, increasing vasculature, and secreting nutrients into the uterine cavity.
• Rising Progesterone levels from the corpus luteum stimulate continued growth of the endometrium and inhibit LH release
  • Without pregnancy: the menstrual phase will follow

Birth Control Methods

Behavioral modification eg Abstinence

Barrier methods eg Condoms

Hormonal methods eg Oral contraceptives

Intrauterine methods eg Intrauterine devices (IUDs)

Permanent methods eg Vasectomy, tubal ligation, and tubal implants.

STI (Sexually Transmitted Infections)

• STI (Sexually transmitted infection) is infectious disease through sexual contact which results in:
  • Reproductive disorders
  • Infertility
• Condoms lower the risk of sexually transmitted infections, such as genital warts
• Vasectomy prevents sperm from leaving the body during ejacluation.
  • Sperm are still produced, but they degenerate and are destroyed by phagocytosis
    • Testosterone production is unhampered and has no effect on sexual desire or performance

Testosterone patches

-Increases GnRH (Gonadotropin-releasing hormone)
-secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) will also be inhibited

Male secondary sex characteristics

• Growth of pubic, axillary, and facial hair
• Enhanced hair growth on the chest or other body areas in some men
• Enlarged larynx and thicker vocal chords results in the Adam's apple" and deepening voice
• Thickened skin and increased secretions of sebaceous glands (the oilier skin often results in acne)

Chlamydia

• Scar tissue in her uterine tubes
  • Fertilization occurs in the uterine tubes.
    • Implantation occurs in the uterus: Mrs. Jones has scar tissue and inflammation in the uterine tubes, and the fertilized ovum will have more difficulty making its way from the uterine tube to the uterus, resulting in an ectopic pregnancy

Hormonal birth control

• Contain only progesterone that prevents Gonadotropin's release.

Tubal ligation

- Surgeon makes an insertion into the wall of the body cavity, cuts through the uterine tubes, and either ligates or cauterizes their ends.

• Doesn't affect drive as progesterone and estrogens travel from the ovaries to the blood.