Bio 1108 Reproductive System Male and Female Anatomy

Figure 16.2a Male reproductive organs. Ureter Urinary bladder Seminal vesicle Prostatic urethra Ampulla of ductus deferens Pubis Membranous urethra Ejaculatory duct Urogenital diaphragm Rectum Erectile tissue of the penis Prostate Bulbourethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce (a) Scrotum External urethral orifice

Male Anatomy The Path of Sperm Testis Epididymis Ductus Deferens Urethra M=Models FP= Fetal Pig Testis-M, FP Epididymus-M Ductus deferens-M, FP Seminal vesicle-M Prostrate-M Urethra –M, FP Penis-M, FP Microscope sperm 3 4 5 6 7 2 1

3 2 Produces sperm 1 Ductus (vas) Spermatic cord Deferens is inside Blood vessels and nerves 3 Seminiferous tubule Rete testis Ductus (vas) deferens Lobule 2 Septum Tunica albuginea Epididymis Produces sperm 1

BLADDER URETHRA PENIS TESTES DUCTUS DEFERENS

URETHRA PENIS TESTES Vas Deferens (model-inside cord)

bladder Testes Vas deferens Urethra Penis BLADDER

Male Reproductive System bladder Testes Vas deferens Urethra Penis BLADDER

VAS DEFERENS BLADDER BLADDER VAS DEFERENS SEMINAL VESICLE PROSTRATE PENIS PENIS EPIDIDYMIS TESTES TESTES

Urinary bladder Ureter Prostate Ampulla of ductus deferens Seminal vesicle Prostatic urethra Ejaculatory Duct Orifices of prostatic ducts Bulbourethral gland Membranous urethra Ductus deferens Root of penis Erectile tissue of penis Epididymis Shaft (body) of penis Testis Spongy urethra Glans penis Prepuce External urethral orifice (b)

Located in the Seminiferous Tubules Spermatogenesis: Sperm Production Starts at Puberty Located in the Seminiferous Tubules Mitosis of Spermatogonium Produces 2 cells One remains for Mitosis The other continues Meiosis I: genetic variation introduced Meiosis II How One cell of 2n (diploid) DNA becomes four cells of n (haploid) DNA Seminiferous tubule Basement membrane Spermatogonium (stem cell) Daughter cell type A (remains at basement membrane as a stem cell) Mitosis Growth Daughter cell type B (moves toward tubule lumen) Enters prophase of meiosis I Primary spermatocyte Meiosis Meiosis I completed Secondary spermatocytes Meiosis II Early spermatids Spermatogenesis Late spermatids Following Meiosis I and II: All spermatids have and half the amount of DNA- n, they are haploid. Spermiogenesis -last stage of sperm development: Sperm develop a flagella Spermiogenesis Sperm Lumen of seminiferous tubule next EPIDIDYMIS

Figure 16.5 Structure of sperm. Plasma membrane Neck Tail Head Midpiece Axial filament of tail Distal centriole Acrosome Nucleus Mitochondria (a) Proximal centriole (b)

Hormonal Control of Sperm Production: Hypothalamus The hypothalamus releases gonadotropin-releasing hormone (GnRH). Hormonal Control of Sperm Production: It begins in the Brain . Hormones are produced released to the blood. Hormones travel by the blood to target tissues. GNRH travels to the pituitary and stimulates the release of LH. The LH travels to the Testis. Testosterone increases in the Seminiferous Tubules. FSH released by the pituitary travels to the Testis. 1 1 GnRH GnRH stimulates the anterior pituitary to release gonadotropins—FSH and LH. Anterior pituitary 2 FSH stimulates spermatogenic cells to produce sperm. 3 5 2 LH stimulates the interstitial cells to release testosterone, which serves as the final trigger for spermatogenesis. Testosterone then enhances spermatogenesis. 4 FSH LH Testosterone 3 4 5 Rising level of testosterone exerts feedback inhibition on the hypothalamus and pituitary. 5 LH stimulates Testosterone production. Testosterone Levels Increase. FSH Stimulates Sperm Production. Number of Sperm increase. For Sperm development to occur the testosterone levels must increase. Testosterone Primary and secondary sex characteristics Seminiferous tubule in testis Supporting cell FSH and testosterone stimulate sperm production Spermatogenic cells Spermatogenesis Negative Feedback when there are too many Sperm. KEY: Stimulates Inhibits

Female Anatomy Suspensory ligament of ovary (part of broad ligament) Infundibulum Uterine tube Ovary Fimbriae Uterus (fundus) Uterosacral ligament Round ligament Urinary bladder Pubic symphysis Rectum Mons pubis Cervix Urethra Vagina Clitoris Anus Hymen Labium minus Greater vestibular gland Labium majus (a)

Female Anatomy THE Path of the Egg Ovary Uterine Tube Uterus Vagina 1 2 3 Microscope follicle 4

OVARY Uterine Tube VAGINA BLADDER URETHRA UTERUS

Figure 16.8b The human female reproductive organs. Suspensory ligament of ovary Uterine (fallopian) tube Ovarian blood vessels Fundus of uterus Lumen (cavity) of uterus Ovary Broad ligament Infundibulum Uterine tube Fimbriae Ovarian ligament Round ligament of uterus Body of uterus Endometrium Myometrium Wall of uterus Perimetrium Ureter Uterine blood vessels Cervical canal Uterosacral ligament Vagina Cervix (b)

OVARY UTERINE HORN VAGINA BLADDER URETHRA OVARY UTERUS VAGINA BLADDER URETHRA

Female reproductive system bladder ovary vagina Urogenital sinus Uterine horns Female reproductive system

vagina Urogenital sinus URETHRA Female Reproductive Organs bladder ovary vagina Urogenital sinus URETHRA Female Reproductive Organs

OVARY UTERINE HORN VAGINA BLADDER URETHRA OVARY UTERUS VAGINA BLADDER URETHRA

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

Oogenesis: Ovum Production Starts in fetal stage Located in the Ovary Mitosis of Oogonium: Produces 2 n cells Meiosis I starts but then stops. Genetic Variation is introduced. 2 million Primary Oocytes All Primary Oocytes are surrounded by cells forming Primary Follicles that will remain in Suspended Animation until Age 10 to 14 years With the onset of Puberty, every 28 Days a few of the Primary Follicles undergo Meiosis I (finish what was started) and Meiosis II (starts but then stops). Primary Oocyte becomes Secondary Oocyte Secondary Oocyte is released by the Ovary. Meiosis II is completed with fertilization by Sperm. Fetus 1 2 Suspended Animation Birth to Puberty 3 Age 10 to 14 years to 50’s 4 4.2 5 5.2 How One cell of 2n DNA becomes One cell of n DNA with 3 Polar Bodies

Growing follicles Primary follicle Degenerating corpus luteum Blood Every 28 Days a few of the Primary Follicles undergo Meiosis I (finish what was started) and Meiosis II (starts but then stops). Primary Oocyte becomes Secondary Oocyte . Secondary Oocyte is released by the Ovary Growing follicles Primary follicle Degenerating corpus luteum Blood vessels Antrum Corona radiata Mature vesicular (Graafian) follicle Germinal epithelium Corpus luteum Developing corpus luteum Ruptured follicle Ovulation Secondary oocyte Figure 16.7 Sagittal view of a human ovary showing the developmental stages of an ovarian follicle.

Figure 16.12a Hormonal interactions of the female cycles. (a) Fluctuation of gonadotropin levels: Fluctuating levels of pituitary gonadotropins (FSH and LH) in the blood regulate the events of the ovarian cycle. LH Plasma hormone level FSH Primary follicle stimulated Day 0 Day 14: Ovulation-release of Secondary OOCYTE from Mature Follicle Day 28

Figure 16.12b Hormonal interactions of the female cycles. Spike in temperature (b) Ovarian cycle: Structural changes in the ovarian follicles during the ovarian cycle are correlated with (d) changes in the endometrium of the uterus during the uterine cycle. Primary follicle Secondary follicle Vesicular follicle Ovulation Corpus luteum Degenerating corpus luteum Follicular phase Ovulation (Day 14) Luteal phase After Ovulation: 24 hour window for fertilization by sperm

Day 14 -15

Day 17 Day 14 (a) Zygote (fertilized egg) Zona pellucida Fertilization Figure 16.16a Cleavage is a rapid series of mitotic divisions that begins with the zygote and ends with the blastocyst. (a) Zygote (fertilized egg) Zona pellucida Fertilization (sperm meets and enters egg) Sperm Uterine tube Ovary Oocyte (egg) Day 17 Uterus Ovulation Endometrium Day 14 Cavity of uterus

Figure 16.12c Hormonal interactions of the female cycles. Preparing the Uterus for the Blastocyst Day 17: Blastocyst arrives at Uterus (c) Fluctuation of ovarian hormone levels: Fluctuating levels of ovarian hormones (estrogens and progesterone) cause the endometrial changes of the uterine cycle. The high estrogen levels are also responsible for the LH/FSH surge in (a). Plasma hormone level Estrogens Progesterone Day 14: Ovulation-release OOCYTE Figure 16.12c Hormonal interactions of the female cycles.

Day 14: Ovulation-release OOCYTE Day 17: Blastocyst arrives at Uterus Menstrual Phase Suspended: No Menses Endometrial glands Blood vessels (d) The three phases of the uterine cycle: Menstrual: Shedding of the functional layer of the endometrium. Proliferative: Rebuilding of the functional layer of the endometrium. Secretory: Begins immediately after ovulation. Enrichment of the blood supply and glandular secretion of nutrients prepare the endometrium to receive an embryo. Functional layer Menstrual flow Basal layer 1 5 10 15 20 25 28 Days Menstrual phase Proliferative phase Secretory phase The menstrual and proliferative phases occur before ovulation, and together correspond to the follicular phase of the ovarian cycle. The secretory phase corresponds in time to the luteal phase of the ovarian cycle. Fertilization of Oocyte by Sperm

Day 14: Ovulation-release OOCYTE Menstrual Phase occurs: Menses No Fertilization Endometrial glands Blood vessels (d) The three phases of the uterine cycle: Menstrual: Shedding of the functional layer of the endometrium. Proliferative: Rebuilding of the functional layer of the endometrium. Secretory: Begins immediately after ovulation. Enrichment of the blood supply and glandular secretion of nutrients prepare the endometrium to receive an embryo. Functional layer Menstrual flow Basal layer 1 5 10 15 20 25 28 Days Menstrual phase Proliferative phase Secretory phase The menstrual and proliferative phases occur before ovulation, and together correspond to the follicular phase of the ovarian cycle. The secretory phase corresponds in time to the luteal phase of the ovarian cycle.