Reproductive System Ch 27

Difference between Meiosis and Mitosis

Meiosis I Interphase Prophase I Metaphase I Anaphase I Telephase I

Meiosis II Prophase II Metaphase II Anaphase II Telephase II

Male Reproductive System

Human reproduction involves intricate anatomy and complex behavior Reproductive Anatomy of the Human Male. External: - penis - scrotum Internal: - gonads - accessory sex glands and ducts.

Male Reproductive System

Testes

Male Reproductive System

Male Reproductive System

External structure of the penis: glans penis prepuce (foreskin) There is no verifiable health benefit to circumcision.

Circumcision foreskin glans penis urethral opening sutures shaft corona

The engorgement of the penis with blood causes an erection. The penis is composed of three layers of spongy erectile tissue. During sexual arousal the erectile tissue fills with blood from arteries. The resultant increased pressure seals off the veins that drain the penis. The engorgement of the penis with blood causes an erection. urethra

Testes are the male gonads. seminiferous tubules- form sperm Leydig cells (interstitial cells)- produce androgens (ex. Testosterone, ABP).

Testes are located in the scrotum, outside the body cavity. This keeps testicular temperature cooler than the body cavity. The testes develop in the body cavity and descend into the scrotum just before birth.

Sperm Pathway Membranous urethra Prostatic urethra

seminal vesicle prostate gland bulbourethral gland Semen Seminal fluid is thick, yellowish, and alkaline. It contains mucus, fructose, a coagulating enzyme, ascorbic acid, and prostaglandins. Accessory glands: seminal vesicle prostate gland bulbourethral gland

Contains fructose, asorbic acid, coagulating enzyme, prostaglandin Seminal vesicle: A pair of glands that secrete a liquid component of semen into the vas deferens. Secretion is alkaline Contains fructose, asorbic acid, coagulating enzyme, prostaglandin Seminal Vesicle

Prostate gland: Location- surrounds and opens into the urethra where it leaves the bladder. Secretion- slightly alkaline fluid that activates the sperm and prevents them from sticking together Prostate problems are common in males over 40. Prostate cancer is one of the most common cancers in men. Prostate

Bulbourethral gland (Cowper’s gland): Location- paired glands that lie beneath the prostate Secretion- a thick, clear alkaline mucous that drains into the membranous urethra. Function- It acts to wash residual urine out of the urethra when ejaculating semen-- raises pH; neutralizes acidity of urine. Bulbourethral gland

Ejaculation Ejaculation propels sperm from the epididymis to the vas deferens. The vas deferens run from the scrotum and behind the urinary bladder. Here each vas deferens joins with a duct from the seminal vesicle to form an ejaculatory duct. The ejaculatory ducts open into the urethra. The urethra drains both the excretory and reproductive systems.

Ejaculate A male usually ejaculates about 2 – 5 mL of semen; each milliliter containing about 50 – 130 million sperm. Bulbourethral fluid also carries some sperm released before ejaculation. This is one of the reasons why the withdrawal method of birth control has a high failure rate.

Spermatogenesis

Mature Spermatozoa acrosome head nucleus tail mitochondria

Seminiferous Tubules

Seminiferous Tubules Spermatids Spermatozoa 1º spermatocyte Sertoli/ sustenacular cell 2º spermatocyte 1º spermatocyte spermatogonium Interstitial cells

Sperm Maturation & Development

Hormones Involved in Spermatogenesis Gonadotropin Releasing Hormone (GnRH) Follicle Stimulating Hormone (FSH) Interstitial Cell Stimulating Hormone (ICSH=LH) Testosterone Inhibin ABP

Hormonal Control of Spermatogenesis Hypothalamus GnRH Anterior Pituitary ICSH FSH

Hormonal Control of Spermatogenesis ICSH Interstitial Cells Testosterone

Hormonal Control of Spermatogenesis FSH Testosterone Sertoli Cells Spermatogenesis Inhibin

Hormonal Control of Spermatogenesis Feedback Inhibition Inhibin Acts on anterior pituitary Inhibits FSH production Testosterone Acts on hypothalamus Inhibits GnRH production

Some Other Effects of Testosterone muscle and bone growth facial and pubic hair growth thickening of vocal cords growth of pharyngeal cartilage hair follicle effects stimulates sebaceous glands Increased BMR

Vasectomy

Female Reproductive System

Female Reproductive System uterine tube Ovary uterus cervix Bladder vagina clitoris urethra l. majora l. minora

Internal reproductive: Vagina Cervix Fallopian tube (uterian tube/oviducts) Fimbrae Ovary Uterus Endometrium Myometrium Perimetrium uterus uterine tube ovary endometrium fimbriae myometrium perimetrium cervix vagina

Fimbrae & Fallopian Tube

Oogenesis in the Ovary

Oogenesis Ovary- contains 400,000 oocytes; release about 500 in a lifetime Ovary- under influence of FSH. The follicles mature every 28 days Primary follicle produces estrogens And primary oocyte completes its 1st division produces 2ndary oocyte and polar body

Oogenesis Aprox 1/2 way through the 28 day cycle the follicle reaches the mature Vesticular or Graffian follicle stage.

Oogenesis Estrogen levels rise and release LH and FSH and triggers ovulation.

Oogenesis The 2ndary oocyte travels down the uterine tube to the uterus. If fertilized by sperm, it will produce a zygote Ovum in uterine tube

Ectopic Pregnancy In most pregnancies, the fertilized egg travels through the fallopian tube to the womb (uterus). Anything that blocks or slows the movement of this egg through these tubes can lead to ectopic pregnancy: Birth defect in the fallopian tubes Scarring after a ruptured appendix Endometriosis Having an ectopic pregnancy before Scarring from past infections or surgery of the female organs The following also increase your risk of an ectopic pregnancy: Age over 35 Getting pregnant while having an intrauterine device (IUD) Had surgery to untie tubes (tubal sterilization) to become pregnant Having had many sexual partners Some infertility treatments  Having your tubes tied (tubal ligation) - more likely 2 or more years after the procedure Had surgery to untie tubes in order to get pregnant Sometimes the cause is unknown. Hormones may play a role. The most common site for an ectopic pregnancy is within one of the two fallopian tubes. In rare cases, ectopic pregnancies can occur in the ovary, abdomen, or cervix. An ectopic pregnancy can occur even if you use birth control.

Ovarian Cyst Cysts are fluid-filled sacs that can form in the ovaries. They are very common. They are particularly common during the childbearing years. There are several different types of ovarian cysts. The most common is a functional cyst. It forms during ovulation. That formation happens when either the egg is not released or the sac -- follicle -- in which the egg forms does not dissolve after the egg is released. Other types of cysts include: Polycystic ovaries. In polycystic ovary syndrome (PCOS), the follicles in which the eggs normally mature fail to open and cysts form. Endometriomas. In women with endometriosis, tissue from the lining of the uterus grows in other areas of the body. This includes the ovaries. It can be very painful and can affect fertility. Cystadenomas. These cysts form out of cells on the surface of the ovary. They are often fluid-filled. Dermoid cysts. This type of cyst contains tissue similar to that in other parts of the body. That includes skin, hair, and teeth.

Endometriosis In some women, endometrial tissue grows outside the uterus. Growths may form on the ovaries, fallopian tubes, bladder, intestines, and other parts of the body. When it's time for your period, these clumps break down, but the tissue has no way to leave the body. While this is rarely dangerous, it can cause pain and produce scar tissue that may make it tough to get pregnant. There are treatments for endometriosis, but there is no cure.

Oogenesis

Hormones Involved in the Female Reproductive Cycle Gonadotropin Releasing Hormone (GnRH) Follicle Stimulating Hormone (FSH) Luteinizing Hormone (LH) Estrogen Progesterone Inhibin Relaxin

Female Hormonal Cycle Hypothalamus GnRH Anterior Pituitary LH FSH

Female Hormonal Cycle FSH LH Follicle Cells Estrogen

The Uterine Cycle

Hormone Fluctuation

Some Other Effects of Estrogen breast development external genitalia growth bone growth fat deposition Increase protein anabolism Decrease blood cholesterol Facilitate calcium uptake Promotes hydration of skin Feminizes brain

Menopause: cessation of ovarian and menstrual cycles. Usually occurs between ages 46 and 54. Due to ovaries decreased responsiveness to gonadotropins. Menopause affects: changes in sexual desire triggers mood swings causes debilitating hot flashes may lead to bone and heart problems short-term memory loss insomnia

Mammary glands. Are present in both males and females. Are not a component of the reproductive system. Contain epithelial tissue that secrete milk. Milk drains into a series of ducts opening at the nipple.

Mammary Gland

Life’s Greatest Miracle http://www.pbs.org/wgbh/nova/miracle/program.html

INQUIRY Where are sperm cells formed within the testes? What portion of the sperm contains 23 chromosomes? What 3 accessory glands produce seminal fluid? What is the term for the primary human sex organs? What structure is formed following ovulation? 6. What hormones are produced from the corpus luteum? 7. List several effective means for preventing conception.