BHAP - 4th Quarter - LT

REPRODUCTIVE SYSTEM

                •The reproductive organs of both genders are said to be in “slumber” until puberty sets in.

Developmental Aspects of the Reproductive System

                •The sex of an individual is already determined at the time of fertilization as:

                                FEMALE – XX chromosome combination on the 23^rd pair (SEX CHROMOSOMES)

                                MALE – XY chromosome combination

                •The GONADS (Primary Sex Organ) do not begin to form until about the 8^th week of embryonic development

                                TESTES – Male Gonads

                                OVARY – Female Gonads

•Prior to this time, the embryonic reproductive structures of males & females are IDENTICAL, and are said to be in the INDIFFERENT STAGE.

•After the gonads have formed, development of the accessory organs & external genitalia begins.

•Whether male or female structures will form depends entirely on whether TESTOSTERONE is present or absent.

•The usual case is that, once formed, the embryonic testes produce testosterone and the development of the male duct system & external genitalia follows.

•When testosterone is NOT produced as in the case of the female embryos that form ovaries, the female ducts and external genitalia results.

•Any interference with the normal pattern of sex hormone production in the embryo results in a bizarre abnormalities.

•If the embryonic testes fail to produce testosterone, a genetic male develops the female accessory structures and external genitalia.

•PSEUDOHERMAPHRODITES / mismatched - if a genetic female is exposed to testosterone (if the mother has androgen-producing tumor of her adrenal gland) the embryo has ovaries but develops male accessory ducts and glands.

•TRUE HERMAPHRODITES – rare individuals who possess both ovarian and testicular tissues.

•ABDOMINAL CAVITY – where male testes develops; approximately the same location of the female ovaries.

•The male testes  descend to enter the scrotum about 1 month before birth.

•CRYPTORCHIOISM - condition where testes fails to descend

                                    - sterility might happen if not operated

MALE REPRODUCTIVE SYSTEM

                • Manufacture male gametes (sperm) and deliver them to the woman’s reproductive tract.

Path of Testicles

     Abdominal Cavity

     Inguinal Canal

     Scrotum

Divisions of the Male Reproductive System

MALE GONADS / TESTES	•Primary sex organ of the male •Exocrine Function: sperm-producing •Endocrine Function: testosterone-producing •Approx. 4 cm. long x 2.5 cm wide •TUNICA ALBUGINEA – fibrous connective tissue capsule which surrounds each testis and divides it into 2 tiny lobules 1 lobule = 1 – 4 tightly coiled Seminiferous Tubules •SEMINIFEROUS TUBULES – where sperm cells are actually produced •RETE TESTIS – network of tubules located on the side of the testis carrying sperm from the seminiferous tubules to the epididymis •INTERSTITIAL CELLS OF LEYDIG – lying in the soft tissue surrounding the Seminiferous tubules                                                            -  produces testosterone
DUCT SYSTEM (Transports System)	EPIDIDYMIS	•Provides temporary storage site for immature sperm cells from the seminiferous tubules & rete testis •While the young sperm cells make their way along the epididymis (20 days), they mature, gaining the ability to swim •When a male is sexually stimulated, the wall of the epididymis contract to expel the sperm to the vas deferens
	DUCTUS / VAS DEFERENS	•Propels live sperm from the epididymis into the urethra •Ejaculation – “to shoot forth” •At the moment of ejaculation, the walls create peristaltic waves that squeeze the sperms forward
	EJACULATORY DUCT	•Passes through the prostate gland to merge with the urethra
	URETHRA	•Extends from the bladder to the tip of the penis •Carries both urine & semen, however, they never pass the urethra at the same time •When ejaculation happens, sperm enters the prostatic urethra from the ejaculatory ducts, the urinary bladder spinchter contracts (shuts off) •This event not only prevents the passage of urine into the urethra, but also prevents sperm from entering the urinary bladder
		Prostatic	•surrounded by the prostate gland
		Membranous	•spanning the distance from the prostatic urethra to the penis
		Spongy / Penile	•runs through the length of the penis
ACCESSORY REPRODUCTIVE GLANDS / ORGANS	SEMINAL VESICLE	•Located at the base of a urinary bladder •Contributes 60% of the fluid volume •Thick, yellowish secretion •Nutrients that activates the sperm cell:      sugar (fructose)      Vit. C      Prostaglandin •The duct of the seminal vesicle joins the vas deferens on the same side to form EJACULATORY DUCT
	PROSTATE GLAND	•A single gland about the size of a chestnut •It encircles the upper part of the prostatic urethra just below the J. bladder •The secretion is a milky fluid that plays a role in activating sperm •It is located immediately anterior to the rectum, its size & texture can be palpated by digital examination through the anterior rectal wall
	COWPER’S / BULBOURETHRAL GLAND	•Tiny, pea-sized gland inferior to the prostates •Produce a thick, clear mucus, that strains into the penile urethra •This secretion is the first to pass down the male urethra when a man becomes sexually excited •It cleanses the urethra of traces of acidic urine •Serves a lubricant during copulation
EXTERNAL GENITALS	SCROTUM	•”pouch” •Divided sac of skin that hangs outside the abdominal cavity •Between the legs and at the root of the penis •Provides the testes a temperature which is below body temperature because viable sperm cannot be produced at normal body temperature •Provides a temperature  3˚  lower than the normal body temperature specified to produce healthy sperm
	PENIS	•Designed to deliver sperm into the female birth canal PARTS: 1.        Shaft – skin-covered part which ends in an enlarged tip 2.        Glans penis – represents the enlarged tip 3.        Prepuce / Foreskin – a cuff of skin that folds downward because the skin covering the penis is loose                                 - removed in circumcision 4.        Muscles that forms the penis:      - Corpus cavernosa penis      - Corpus spongiosum penis

SEMEN

                •Relative alkalinity is pH 7.2-7.6 that help neutralize the acid environment of the female vagina which is pH 3.5-4.0

                •The basicity protects the delicate sperm which become sluggish under acidic conditions

                •Contains SEMINALPLASMIN – antibiotic chemical that prevents bacterial multiplication

                •Contain RELAXIN – enhance sperm motility

                •Milky white, sticky mixture of sperm and accessory gland secretions

                •Accessory Gland secretions provide the medium and nutrients

                •The fructose in the seminal vesicle provides essentially the energy fuel of the sperms

                •The amount of semen propelled per ejaculation is relatively small, only 2 – 5 mL or a about a teaspoonful but there are 50 – 150 M/ mL

 

CAUSES OF MALE INFERTILITY:

1.        Obstructions in the duct system

2.        Hormonal imbalances

3.        Excessive alcohol

FACTORS ANALYZED in SEMEN ANALYSIS:

1.        Sperm count (lower than 20M/mL makes pregnancy improbable)

2.        Motility and morphology (shape and maturity)

3.        Semen volume

4.        pH

5.        Fructose content

What is the influence of FSH(Follicle-stimulating hormone) and LH(Luteinizing hormone) of the anterior lobe of the Pituitary Gland to male reproduction?

The hypothalamus secretes gonadotropin-releasing hormone (GnRH), which enters the blood vessels leading to the anterior pituitary gland. In response, the anterior pituitary gland secretes the gonadotropins called luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH, which in males has been referred to as interstitial cell-stimulating hormone (ICSH), promotes development of the interstitial cells of the testes, and they, in turn, secrete male sex hormones. FSH stimulates the sustentacular cells of the seminiferous tubules to proliferate, grow, mature, and respond to the effects of the male sex hormone testosterone. Then, in the presence of FSH and testosterone, these cells stimulate the spermatogenic cells to undergo spermatogenesis, giving rise to sperm cells. The sustentacular cells also secrete a hormone called inhibin, which inhibits the anterior pituitary gland by negative feedback and thus prevents oversecretion of FSH.