The Reproductive System Gonads— Duct system— External genitalia—

The Reproductive System Gonads—Testes / Ovaries—produce: gametes (sex cells) and hormones Duct system —delivers gametes External genitalia —for intercourse

Male Reproductive System Overview Testes Duct system —Epididymis / Ductus (vas) deferens / Urethra (Accessory organs --Seminal vesicles / Prostate / Bulbourethral glands) External genitalia —Penis / Scrotum

Male Reproductive System Figure 16.2a

Male Reproductive System Figure 16.2b

Testes Figure 16.1

External Genitalia Three areas of spongy erectile tissue around urethra Erections occur when erectile tissue fills with blood during sexual excitement Nitrogen monoxide (NO) relaxes arterioles More blood enters penis Veins constrict—less blood leaves

Spermatogenesis Figure 16.3 (1 of 2)

Spermatogenesis Figure 16.3 (2 of 2)

Structure of a Sperm Figure 16.5b

Structure of a Sperm Figure 16.5a

Female Reproductive System Ovaries Duct System—Uterine tubes (fallopian tubes) / Uterus / Vagina External genitalia —Labia, clitoris

Female Reproductive System Figure 16.8a

Female Reproductive System Figure 16.8b

External Genitalia (Vulva) Figure 16.9

Ovaries Figure 16.7

Preparing oocytes 0) . .

Preparing oocytes 0) (Before ova begin to mature) . Primary follicle Graafian (vesicular) follicle . Ovulation . Ruptured follicle (The end)

Preparing oocytes 0) Total supply of ova present at birth. Releasing ova begins at puberty Primary follicle —contains immature oocyte Graafian (vesicular) follicle —growing follicle with maturing oocyte Ovulation —when the egg is mature, follicle ruptures; occurs every ~28 days Ruptured follicle  corpus luteum Reproductive ability ends at menopause

Walls of the Uterus Endometrium— Myometrium— Perimetrium (visceral peritoneum)—

Walls of the Uterus Endometrium Inner layer Allows implantation of fertilized egg Sloughs off if no pregnancy occurs (menses) Myometrium —middle layer—smooth muscle Perimetrium (visceral peritoneum)—outermost serous layer of the uterus

Meiosis ♂ ♀ Gamete number ♂ ♀ Gamete size ♂ ♀ Gamete structure

♂ four functional sperm ♀one functional ovum and three polar bodies Meiosis ♂ ♀ Gamete number ♂ four functional sperm ♀one functional ovum and three polar bodies Gamete size ♂ tiny ♀ large Gamete structure ♂ motile, nutrients in seminal fluid ♀ non-motile. nutrient reserves in cytoplasm

Follicle Development in Ovary Oogenesis Meiotic Events Follicle Development in Ovary Before birth Primary oocyte Primary follicle Oocyte Oogonium (stem cell) Mitosis Follicle cells 2n Figure 16.10, step 1

Follicle Development in Ovary Oogenesis Meiotic Events Follicle Development in Ovary Before birth Primary oocyte Primary follicle Oocyte Primary oocyte (arrested in prophase I; present at birth) Oogonium (stem cell) Mitosis Growth Follicle cells 2n Figure 16.10, step 2

Follicle Development in Ovary Oogenesis Meiotic Events Follicle Development in Ovary Before birth Childhood Primary oocyte Primary follicle Oocyte Primary oocyte (arrested in prophase I; present at birth) Oogonium (stem cell) Mitosis Growth Follicle cells (ovary inactive) 2n Figure 16.10, step 3

Follicle Development in Ovary Oogenesis Meiotic Events Follicle Development in Ovary Before birth Childhood Primary oocyte Primary oocyte (still arrested in prophase I) Primary follicle Oocyte Growing follicle Primary oocyte (arrested in prophase I; present at birth) Oogonium (stem cell) Each month from puberty to menopause Mitosis Growth Follicle cells (ovary inactive) 2n Figure 16.10, step 4

Oogenesis Primary oocyte (still arrested in prophase I) Mature vesicular (Graafian) follicle Primary follicle Growing follicle Each month from puberty to menopause 2n Figure 16.10, step 5

Oogenesis Primary oocyte (still arrested in prophase I) Mature vesicular (Graafian) follicle Primary follicle Ovulated secondary oocyte Growing follicle Each month from puberty to menopause Meiosis I (completed by one primary oocyte each month) First polar body Ovulation Secondary oocyte (arrested in metaphase II) 2n n Figure 16.10, step 6

Oogenesis Primary oocyte (still arrested in prophase I) Mature vesicular (Graafian) follicle Primary follicle Ovulated secondary oocyte Growing follicle Each month from puberty to menopause Meiosis I (completed by one primary oocyte each month) First polar body Sperm Ovulation Secondary oocyte (arrested in metaphase II) 2n n Figure 16.10, step 7

Oogenesis Primary oocyte (still arrested in prophase I) Mature vesicular (Graafian) follicle Primary follicle Ovulated secondary oocyte Growing follicle Each month from puberty to menopause Meiosis I (completed by one primary oocyte each month) First polar body Meiosis II of polar body (may or may not occur) Polar bodies (all polar bodies degenerate) Ovum Second polar body Meiosis II completed (only if sperm penetration occurs) Sperm Ovulation Secondary oocyte (arrested in metaphase II) 2n n Figure 16.10, step 8

Follicle Development in Ovary Oogenesis Meiotic Events Follicle Development in Ovary Before birth Childhood Primary oocyte Primary oocyte (still arrested in prophase I) Mature vesicular (Graafian) follicle Primary follicle Oocyte Ovulated secondary oocyte Growing follicle Primary oocyte (arrested in prophase I; present at birth) Oogonium (stem cell) Each month from puberty to menopause Meiosis I (completed by one primary oocyte each month) First polar body Mitosis Growth Meiosis II of polar body (may or may not occur) Polar bodies (all polar bodies degenerate) Ovum Second polar body Meiosis II completed (only if sperm penetration occurs) Sperm Ovulation Secondary oocyte (arrested in metaphase II) Follicle cells (ovary inactive) 2n n Figure 16.10, step 9

Uterine (Menstrual) Cycle Cyclic changes of the endometrium Regulated by estrogens (EST) and progesterone (PRO) FSH and LH regulate the production of estrogens and progesterone ~ 28 days for both cycles Ovulation ~ midway through cycle, ~day 14 FSH & LH Anterior pitutitaryOvaries EST & PRO Ovaries  Anterior pitutitary

Fluctuation of Gonadotropin Levels Figure 16.12a

Fluctuation of Ovarian Hormone Levels Figure 16.12b

Ovarian Cycle Figure 16.12c

Uterine (Menstrual) Cycle Figure 16.12d

Developmental Stages of Ovarian Follicle Figure 16.7

Mechanisms of Fertilization

Mechanisms of Fertilization Sperm reach oocyte, enzymes pierce corona radiata Acrosomal reaction--enzymes pierce oocyte membrane Receptors on oocyte pull head of sperm into cell Ca++ ions harden membrane, blocking other sperm Meiosis II forms ovum and a polar body Fertilization: genetic material of gametes combine to form a zygote

Cleavage Figure 16.15 Fertilization Secondary oocyte Ovulation Uterus Endometrium Uterine tube Blastocyst cavity Inner cell mass Trophoblast Zygote (fertilized egg) Early cleavage 4-cell stage Early blastocyst Late blastocyst (implanting) Morula Ovary (a) (b) (d) (e) (c) Figure 16.15

The Blastocyst (Chorionic Vesicle) Primary germ layers are eventually formed Ectoderm—outside layer Mesoderm—middle layer Endoderm—inside layer The late blastocyst implants in the wall of the uterus (by day 14)

Derivatives of Germ Layers Ectoderm Nervous system Epidermis of the skin Endoderm Mucosae Glands Mesoderm Everything else

Photographs of a Developing Fetus Figure 16.18a

Possible test questions: What do gonads produce? How does gametogenesis differ in males and females? Describe the locations of ovaries and testes. How do FSH, LH, EST and PRO levels change over the course of a menstrual cycle? How and why does the uterine lining change over the course of a menstrual cycle? How does a follicle change over the course of a menstrual cycle?