Reproductive System

REPRODUCTIVE SYSTEM

I. Introduction to Male Reproductive System

A. Male reproductive organs

1. Testes

a. Location

b. Spermatic cord

c. Descent of the testes and Cryptorchidism

d. Structure

1. Tunica albuginea

2. Seminiferous tubules

aa. Spermatogenesis occurs here

bb. Interstitial cells (of Leydig) - testosterone!!

cc. Sustentacular (Sertoli) cells

3. Rete testis

4. Epididymis

5. Ductus/Vas deferens

2. Spermatogenesis - cell types involved underlined

a. Spermatogonia -

b. Sustentacular (Sertoli) cells - blood-testis barrier

c. Meiosis - draw out the 8 stages on a separate sheet of paper

d. Primary spermatocyte (2N or diploid)

e. Secondary spermatocyte (N or haploid)

f. Spermatid (N or haploid) and spermiogenesis

g. Spermatozoa ("sperm")(N=23)

3. Anatomy of a Spermatozoan

a. Head

1. Acrosomal head with hydrolytic enzymes

2. Nucleus

b. Middle Piece (body) -

c. Tail -

d. Capacitation - event in which the spermatozoa become active, motile and fully functional. Requires contact with secretions from the seminal vesicles and secretions inside the female reproductive tract

B. Male Reproductive Tract

1. Internal structures

a. Epididymis

1. Highly coiled tube

2. Fx:

b. Ductus/Vas deferens

1. Straight, muscular tube

2. Fx:

3. Ampulla - enlarged end of ductus deferens

4. Ejaculatory duct - formed from union of ampulla and seminal vesicle duct

c. Seminal vesicles

1. Convoluted, sac-like gland at posterior base of urinary bladder

2. Fx:

d. Prostate gland

1. Chestnut shaped gland inferior to bladder

2. Fx:

3. Prostatic urethra - cuts through center of prostate

4. Seminalplasmin - antibiotic produced by Prostate

5. Prostatic Hypertrophy

e. Bulbourethral/Cowper's glands

1. Pea-sized glands below prostate

2. Fx:

f. Semen - sperm cells + seminal fluid

2. External structures

a. Scrotum - sac enclosing the testes

b. Penis

1. Root

2. Shaft

3. Glans

4. Prepuce

5. Erectile Tissues

a. Corpora cavernosa (paired)

b. Corpus spongiosum

C. Hormonal Control of Male Reproductive Functions

1. Hypothalamus

a. GnRH - stimulates release of FSH and LH from Anterior Pituitary

2. Adenohypophysis

a. FSH - stimulates Sustentacular cells to release substances that begin the process of spermatogenesis and spermiogenesis (Sustentacular cells also secrete inhibin)

b. LH (ICSH) - stimulates Interstitial cells to release testosterone

3. About the Male Sex Hormones (androgens)

a. Testosterone Functions

1. Maturation of Spermatozoa

2. Maintains Accessory Organs of Male Reproductive Tract

3. Secondary Sex Characteristics (growth of body hair, enlargement of larynx and thickening of vocal cords, thickening of skin, increased muscle mass, thickened and strengthened bones)

b. Regulation of Testosterone Release

c. Negative feedback

1. High testosterone levels inhibit release of GnRH (reduces LH levels)

2. Testosterone levels drop

II. Introduction to Female Reproductive System

A. Female reproductive organs: Primary/essential organs

1. Ovaries

a. Descend from near kidneys during development

b. Ligaments

1. Broad

2. Ovarian - attached to inferior ovary and lateral uterus

c. Structure of the Ovary and the Ovarian Cycle

1. Outer cortex contains follicles with developing oocytes inside:

aa. Primordial follicle - fetus begins with over a million (most undergo atresia prior to and after birth)!!

bb. Primary oocyte (immature "egg") - undergoes Meiosis I (2N=46)

cc. Developing follicles

1. Primary follicle - layers of cuboidal cells; zona pellucida (glycoprotein layer) forms around oocyte

2. Secondary follicle - six-twelve cell layers thick; beginning to form an antrum (fluid-filled cavity)

dd. Graafian ("Tertiary") follicle - mature follicle that secretes mainly estrogen (found in antrum) with secondary oocyte pushed to one side (make a sketch to the side)

ee. Corpus luteum - temporary endocrine organ that secretes mainly progesterone and maintains pregnancy in the first 8 weeks until the placenta is formed

ff. Corpus albicans - scar left by degenerated corpus luteum

2. Inner medulla

aa. CT, blood vessels, lymphatics and nerves

d. Oogenesis - formation of the ovum

1. Primary oocyte (2N=46)

2. Meiosis -

3. Secondary oocyte (N=23)

4. Ovum - mature egg (N=23)

5. Polar bodies - nonfunctional egg cells with very little cytoplasm

6. Zygote - formed from fusion of sperm and ovum (2N=46)

e. Follicle maturation and hormonal effects

1. FSH - stimulates growth of follicle cells

2. Follicle cells - surround the oocyte and secrete female hormones

3. Graafian follicle - undergoes ovulation (release of secondary oocyte from ovary)

B. Hormonal Control of Female Reproductive Functions

1. Hypothalamus

a. GnRH - stimulates release of FSH and LH

2. Adenohypophysis

a. FSH - follicles
b. LH - corpus luteum

3. Ovaries

a. Estrogen - produced mainly by follicle cells
b. Progesterone - produced mainly by corpus luteum

4. Female Reproductive Cycles

a. Ovarian Cycle (3 stages)

1. Follicular phase (FSH dominant)

FSH stimulates follicle development. The Graafian follicle secretes estrogen and smaller amounts of progesterone and contains the secondary oocyte which will be ovulated in the next stage.

2. Ovulation

LH stimulates release of the ovum from the ovary

3. Luteal phase (LH dominant)

LH promote the development of the Corpus luteum which secretes progesterone.

b. Uterine Cycle (ave. 28-day cycle)(3 stages that occur simultaneously with the ovarian cycle)

1. Menses

Decreasing estrogen and progesterone from degenerating corpus luteum promotes sloughing off of the endometrium.

2. Proliferative phase

Rising estrogen levels promote the build-up of the endometrium

3. Secretory phase

Progesterone released from the corpus luteum promotes the development of the glands and b.v.'s of the endometrium, preparing the uterus for implantation of the embryo.

5. Menopause

a. Ovaries unresponsive to FSH and LH
b. Decreased estrogen levels

C. Female reproductive organs: Secondary/accessory organs (please see lab checklist for structures you must be familiar with for lecture and lab)

1. Internal

a. Oviduct (Uterine tubes, Fallopian tubes)

1. Structure

2. Fx:

b. Uterus

1. Structure

Endometrium - inner layer
Myometrium - smooth muscle (bulk of uterus)
Perimetrium - outer layer

Cervix - narrow, inferior portion of uterus

2. Ligaments

Broad
Round
Ovarian

c. Vagina

1. Stratified squamous epithelium, mucous glands
2. Fx: receives sperm from male

d. Mammary Glands

1. Alveoli - location of milk
2. Lactiferous ducts
3. Lactiferous Sinus ("Ampulla") - enlarged area

e. Development of Mammary glands

1. Estrogen - promotes development in female
2. Pregnancy

ii. Estrogen - ductile system
iii. Progesterone - alveoli
iv. Prolactin - milk production

2. External genitalia (vulva) [more Lab stuff!]

a. Labia majora - homologous to scrotum
b. Labia minora
c. Clitoris
d. Vestibule
e. Greater Vestibular (Bartholin's) glands
f. Paraurethral (Skene's) glands
g. Hymen

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Last Updated 06/08/07