Difference between Meiosis and Mitosis

Meiosis I Interphase Prophase IMetaphase IAnaphase ITelephase I

Meiosis II Prophase IIMetaphase IIAnaphase IITelephase II

Male Reproductive System

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

Male Reproductive System

Testes

Male Reproductive System

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

Circumcision foreskinglans penisurethral opening sutures shaft corona

 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.

 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 Prostatic urethra Membranous urethra

Semen  Seminal fluid is thick, yellowish, and alkaline.  It contains mucus, fructose, a coagulating enzyme, ascorbic acid, and prostaglandins.  Accessory glands: 1.seminal vesicle 2.prostate gland 3.bulbourethral gland

Seminal Vesicle 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

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 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. Ejaculation

 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. Ejaculate

Spermatogenesis

Mature Spermatozoa tail mitochondria nucleus acrosome head

Seminiferous Tubules

spermatogonium 1º spermatocyte 2º spermatocyte spermatids Sertoli cell spermatozoa Seminiferous Tubules

Sperm Maturation & Development

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

HypothalamusHypothalamus Anterior Pituitary GnRH FSHICSH Hormonal Control of Spermatogenesis

Interstitial Cells ICSH Testosterone Hormonal Control of Spermatogenesis

Sertoli Cells Testosterone Spermatogenesis FSH Inhibin Hormonal Control of Spermatogenesis

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

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

cervix vagina fimbriae uterine tube ovary uterus bladder urethra clitoris l. minora l. majora Female Reproductive System

External genitalia: Vulva Labia majora Labia minora Clitoris Mons pubis Vestibule mons pubis clitoris l. minora l. majora

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

Biology 100 Human Biology uterine tube ovary egg uterus cervix vagina endometrium myometrium perimetrium

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 1 st 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. Estrogen levels rise and release LH and FSH and triggers ovulation. The 2ndary oocyte travels down the uterine tube to the uterus. If fertilized by sperm, it will produce a zygote

Oogenesis

Ovum

Hormones Involved in the Female Reproductive Cycle Gonadotropin Releasing Hormone (GnRH) Follicle Stimulating Hormone (FSH) Luteinizing Hormone (LH) EstrogenProgesteroneInhibinRelaxin

HypothalamusHypothalamus Anterior Pituitary GnRH FSHLH Female Hormonal Cycle

Follicle Cells LH Estrogen FSH Female Hormonal Cycle

The Uterine Cycle

Ovarian 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

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INQUIRY 1.Where are sperm cells formed within the testes? 2.What portion of the sperm contains 23 chromosomes? 3.What 3 accessory glands produce seminal fluid? 4.What is the term for the primary human sex organs? 5.What structure is formed following ovulation? 6. What hormones are produced from the corpus luteum? 7. List several effective means for preventing conception.