Endocrinology of reproduction Reproductive System

Anatomy of Male Reproductive System Supporting structures Scrotum 2 chambered sac that contains testes Dartos and cremaster muscles help regulate temperature Penis Perineum Diamond-shaped areas between thighs Testes Series of ducts Epididymides Ductus deferentia Urethra Accessory glands Seminal vesicles Prostate gland Bulbourethral glands

Male Pelvis

Testes Glands Descent Compartments divided by septa Cryptorchidism Exocrine Endocrine Compartments divided by septa Seminiferous tubules Empty into rete testis Empties into efferent ductules Interstitial or Leydig cells Descent Pass from abdominal cavity through inguinal canal to scrotum Cryptorchidism Failure of of one or both of testes to descend into scrotum Prevents normal sperm development

Histology of Testis

Descent of Testes

Sperm Cell Development Spermatozoa produced in seminiferous tubules Spermatogonia divide (mitosis) to form primary spermatocytes Primary spermatocytes (first division of meiosis) divide to form secondary spermatocytes Secondary spermatocytes (second division of meiosis) divide to form spermatids Spermatids develop an acrosome and flagellum Sertoli cells nourish sperm cells and form a blood-testis barrier and produce hormones

Spermatogenesis

Meiosis

Ducts Epididymis Ductus deferens or vas deferens Ejaculatory duct Site of sperm cell maturation Ductus deferens or vas deferens Passes from epididymis into abdominal cavity Ejaculatory duct Joining of ductus deferens and seminal vesicle Urethra Extends from urinary bladder to distal end of penis Passageway for urine and male reproductive fluids 3 parts Prostatic urethra Membranous urethra Spongy or penile urethra

Male Reproductive Structures

Penis Three columns of erectile tissue that engorge with blood Corpora cavernosa (2) Corpus spongiosum (1) Glans penis Prepuce or foreskin covers Circumcision: Surgical removal External urethra orifice

Penis

Accessory Glands Bulbourethral glands Secretions Seminal vesicles Contribute about 5% to semen Secretions Semen Composite of sperm cells and secretions Emission Discharge of semen into prostatic urethra Ejaculation Forceful expulsion of semen from urethra Seminal vesicles Empty into ejaculatory duct Produce about 60% of semen Prostate gland Produces about 30% of semen

Regulation of Sex Hormone Secretion Hypothalamus releases GnRH or LHRH which stimulates LH or ICSH to produce testosterone FSH to stimulate sperm cell formation Inhibin inhibits FSH secretion from anterior pituitary

Puberty and Testosterone Age at which individuals become capable of sexual reproduction Before puberty small amounts of testosterone inhibit GnRH release During puberty testosterone does not completely suppress GnRH release, resulting in increased FSH,LH, and testosterone Testosterone Produced by interstitial cells, adrenal cortex and sustentacular cells Causes development of male sex organs in embryo, stimulates descent of testes, causes enlargement of genitals and necessary for sperm cell formation

Male Sexual Behavior and Male Sex Act Testosterone required to initiate and maintain Male sex act Complex series of reflexes that result in erection of penis, secretion of mucus into urethra, emission, ejaculation Sensations result in orgasm associated with ejaculation and then resolution

Neural Control of Erection Stimulation Tactile or psychological Parasympathetic Erection due to vasodilation of blood vessels Sympathetic Causes erection, emission, ejaculation Erectile Dysfunction

Anatomy of Female Reproductive System Female reproductive organs Ovaries Uterine tubes Uterus Vagina External genital organs Mammary glands

Female Pelvis

Uterus, Vagina, Uterine Tubes, Ovaries and Supporting Ligaments

Ovary Histology

Maturation of Follicle and Oocyte

Maturation and Fertilization of Oocyte

Follicle and Oocyte Development Oogenesis is the production of a secondary oocyte in ovaries Oogonia are cells from which oocytes develop Primary oocytes are surround by granulosa cells and called a primordial follicle Primordial follicle becomes a primary follicle when oocyte enlarges and cells change Primary follicle becomes secondary follicle and enlarges to form mature or graafian follicle Usually only one is ovulated, others degenerate Primary oocyte completes first meiotic division to produce secondary oocyte and a polar body Secondary oocyte begins second meiotic division, which stops in metaphase II

Ovulation and Follicle Fate Follicle swells and ruptures, secondary oocyte is released from ovary Second meiotic division completed when secondary oocyte unites with sperm cell to form zygote Fate of the follicle Graafian follicle become corpus luteum If fertilization occurs, corpus luteum persists If no fertilization, becomes corpus albicans

Uterine Tubes and Uterus Uterine or fallopian tubes or oviducts Open directly into peritoneal cavity to receive oocyte from ovary Transport oocyte or zygote from ovary to uterus Uterus Parts: Body, isthmus, cervix Composed of 3 layers Perimetrium: Serous membrane Myometrium: Smooth muscle Endometrium: Mucous membrane

Vagina and Perineum Perineum Vagina Clinical perineum Divided into two triangles Urogenital: Contains the external genitalia Anal triangle Clinical perineum Region between vagina and anus Episiotomy: Incision to prevent tearing during childbirth Vagina Female organ of copulation Allows menstrual flow and childbirth Hymen covers the vaginal opening or orifice

Female External Genitalia Vulva or pudendum or external female genitalia Vestibule: Space Labia minora: Form borders on sides Clitoris: Erectile structure Corpora cavernosa Corpora spongiosa Labia majora Unite to form mons pubis

Female Perineum

Mammary Glands Organs of milk production located within mammae or breasts Consist of glandular lobes and adipose tissue Cooper’s ligaments support the breasts

Puberty and Menstrual Cycle About 28 days long Phases Menses Proliferative phase Secretory phase Amenorrhea: Absence of a menstrual cycle Menopause: Cessation of menstrual cycles Puberty Begins with menarche or first episode of menstrual bleeding Begins when GnRH levels increase

Menstrual Cycle

Hormone Regulation during Menstrual Cycle

Female Sexual Behavior and Sex Act Female sex act Parasympathetic stimulation Blood engorgement in clitoris and around vaginal opening Erect nipples Mucouslike fluid extruded into vagina and through wall Orgasm not necessary for fertilization to occur Female sexual behavior Depends on hormones Androgens and steroids Depends on psychological factors

Female Fertility and Pregnancy Oocyte can be fertilized up to 24 hours after ovulation Sperm cells can be viable for up to 6 days in female tract Ectopic pregnancy: Implantation occurs anywhere other than uterine cavity Female fertility Sperm ejaculated into vagina during copulation and transported through cervix and uterine tubes to ampulla Sperm cells undergo capacitation

Sperm Cell Movement

Changes in Hormones During Pregnancy

Control of Pregnancy Lactation Behavioral methods Chemical methods Oral contraceptives Injections as Depo-Provera Implants Morning-after pills Surgical methods Vasectomy Tubal ligation Abortions Behavioral methods Abstinence Coitus interruptus Rhythm method Barrier methods Condom Male and female Diaphragm Cervical cap Spermicidal agents

Effects of Aging Male Female Decrease in size and weight of testes Decrease in sperm production Prostate gland enlarges and increase in cancer Impotence is age-related Decrease in sexual activity Female Menopause Decrease in size of uterus and vaginal wall thins Age related increase in breast, uterine, ovarian cancer