REPRODUCTIVE SYSTEM

REPRODUCTIVE SYSTEM

REPRODUCTIVE SYSTEM: Design
* Not for Homeostasis; Instead to Perpetuate the Species
* Sexual Reproduction Results in Genetic Variability
* Internal Fertilization & Gestation
* One Offspring per Pregnancy is Typical

REPRODUCTIVE SYSTEM: Functions
* Production & Support of Gametes
* Formation, Transport & Delivery of Sperm
* Formation & Transport of Ova
* Protect & Support Developing Embryo, and Nourish Fetus
* Deliver the Fetus

REPRODUCTIVE SYSTEM: Overview of Anatomy
* Reproductive Organs
* Associated Ducts
* Accessory Glands
* External Genitalia

MALE ANATOMY: TESTES
* From the Greek for “witness” (e.g., testify)
* Essential organs of reproduction in the male (Male Gonad)
* Site of sperm production
* Suspended in scrotum by spermatic cord
* Oval, ~4.5 cm long, 10.5 - 14 gms

MALE ANATOMY: SCROTUM
* Pouch of skin and fascia evaginated from anterior abdominal wall
* Subdivided into two lateral compartments, indicated by Raphe (Ridge)
* Houses testes, keeps them cool (93F)
* Cremaster muscle brings testes closer to body
* Dartos muscle causes wrinkling

MALE ANATOMY: TESTES
* Develop initially in abdominal cavity (retroperitoneally)
* Descend into scrotum
* Seminiferous tubules: Sites of sperm production
* Interstitial Cells: Secrete Testosterone
* Efferent ductules: Carry sperm from testes
* Epididymis:

MALE ANATOMY: SPERMATIC CORD
* Contains structures passing to and from testes
* Coverings derived from abdominal wall
* Contents include:
o Vas deferens
o Spermatic artery and vein
o Spermatic nerve
o Lymph vessel

MALE ANATOMY: VAS (DUCTUS) DEFERENS
* Carries sperm from epididymis to seminal vesicle
* Passes through inguinal canal into body cavity
* Crosses surface of urinary bladder
* Joins with duct of seminal vesicle to form the ejaculatory duct
* Vasectomy

MALE ACCESSORY GLANDS: SEMINAL VESICLES
* Paired structures posterior to urinary bladder
* Secrete ~60% of seminal fluid
* Fluid is sugary, alkaline
* Rich in carbohydrates, Vitamin C

MALE ACCESSORY GLANDS : PROSTATE GLAND
* Located inferior to urinary bladder, anterior to rectum
* Surrounds prostatic urethra
* Secretes ~25% of seminal fluid
* Enzymes to Liquify Semen

MALE ACCESSORY GLANDS : BULBOURETHRAL GLANDS
* Also called Cowper’s glands
* Lateral to membranous urethra
* Secrete a drop of alkaline mucus
o Cleans, lubricates urethra

MALE ANATOMY: PENIS

* Male copulatory organ
* Functions to introduce sperm into female
* Consists of three erectile bodies
o Two corpora cavernosa
o One corpus spongiosum

MALE ANATOMY: PENIS
* Corpus spongiosum
* Corpora cavernosa
* Prepuce (foreskin):

MALE PHYSIOLOGY: SPERMATOGENESIS
o Occurs in seminiferous tubules
o Spermatogonia divide mitotically
o One Spermatocyte eventually gives rise to Four Sperm via meiosis
o Y Sperm are Smaller, Faster, Prefer Alkaline Environment
o X Sperm are Larger, Stronger, Prefer Acidic Environment


MALE SEXUAL RESPONSE
* Erection
o Arteries dilate, increasing blood in spongy tissue
o Constricts veins, causes erection
* Ejaculation (expulsion)
o Semen passes through urethra
o Contractions of urethra & penile musculature


MALE HORMONAL CONTROLS
* Gonadotropic Hormones
* Testosterone (Male Sex Hormone)

FEMALE ANATOMY: OVARY
* Female Gonad
* All ova arrested at prophase I at birth
* Paired, oval, almond sized
* Supported by ligaments

FEMALE ANATOMY: UTERINE (Fallopian) TUBES
* Site of Fertilization
* Paired, ~10 cm long
* Attach to uterus, one on each side
* Transport via Cilia & Peristalsis

FEMALE ANATOMY: UTERUS
* Usually unpaired; hollow, muscular, pear-shaped organ
* Receives uterine tubes, empties into vagina
* Site of Implantation & Development
* Supported by ligaments
* Uterine wall has three layers

FEMALE ANATOMY: UTERUS
* Fundus: Arches above entry of uterine tubes
* Body: Large triangular lumen
* Isthmus: Narrowed region
* Cervix:

FEMALE ANATOMY: VAGINA
* Functions:
* Located between urethra and rectum
* Lined with stratified squamous E.T.
* Acidic environment (Resident Bacteria)
* Fornix: Circular recess around cervix; upper portion of vagina
* Hymen:
* Bartholin’s glands:

FEMALE ANATOMY: VULVA (External Genitalia)
* Mons pubis: Fatty mound
* Labia majora: Outer Folds of skin, Homologous to scrotum
* Labia minora: Inner folds, Encircle clitoris, forming prepuce
* Clitoris: Homologous to penis, corpora cavernosa

FEMALE ANATOMY: CLITORIS
* Foreskin or Prepuce
* Function – Sexual Pleasure
* Orgasm controlled by Sympathetic Division of ANS

FEMALE ANATOMY: BREASTS
* Structurally – Integument
* Functionally – Reproductive

HORMONAL CONTROL: ADULT FEMALE
* Four hormones involved:

THE OVARIAN CYCLE
* Includes:

FOLLICLE DEVELOPMENT
* Up to 20 follicles begin maturation process monthly
* Only one secondary follicle reaches maturity
* Others undergo atresia (degradation)
* Controlled primarily by FSH
* Causes follicle cells to secrete estrogen


OVULATION
* Caused by LH surge
* Day 14 (28-day cycle)
* Expels ovum into abdominal cavity
* Fimbriae on uterine tube sway vigorously, produce a current
* Fimbriae scratch Graafian follicle, rupture it, pull ovum into tube

FORMATION OF CORPUS LUTEUM
* Ruptured Graafian follicle becomes corpus luteum
* Corpus luteum secretes estrogen, progesterone
* Maintains endometrial lining during pregnancy

THE UTERINE CYCLE

* Proliferative phase
o Follows Menstruation
o Estrogen from follicle stimulates proliferation of endometrium
* Secretory phase
o Follows Ovulation
o Progesterone from corpus luteum stimulates secretion by endometrium
* Menstrual phase

REPRODUCTIVE SYSTEM.ppt