THE REPRODUCTIVE SYSTEM D C Mikulecky Faculty Mentoring

THE REPRODUCTIVE SYSTEM D. C. Mikulecky Faculty Mentoring Program Virginia Commonwealth University

ANATOMY OF THE MALE REPRODUCTIVE SYSTEM • • TESTIS SCROTUM PENIS SEMINAL VESSICLES, PROSTATE GLAND, BULBOURETHRAL GLANDS • EPIDIDYMUS, VAS DEFERENS, URETHRA

TESTES • PRIMARY REPRODUCTIVE ORGANS OR GONADS • PRODUCTION OF SPERM • SUSPENDED OUTSIDE THE BODY CAVITY BY SCROTUM

PENIS • DEPOSITS SPERM IN FEMALE • ERECTILE TISSSUE (VASCULAR) • ERECTION RESULTS FROM GORGING TISSUE WITH BLOOD • ERECTION IS A PARASYMPATHETIC SPINAL REFLEX TO TACTILE AND OTHER STIMULATION ENHANCED BY SYMPATHETIC INHIBITION

SEMINAL VESSICLES, PROSTATE GLAND, BULBOURETHRAL GLANDS • PROVIDE THE BULK OF THE SEMEN, A MIXTURE OF SECRETIONS, SPERM AND MUCOUS • FRUCTOSE AND PROSTAGLANDINS FROM SEMINAL VESSICLES • ALKALINITY AND CLOTTING ENZYMES FROM PROSTATE • LUBRICANT FOR INTERCOURSE FROM BULBOURETHRAL GLANDS

EPIDIDYMUS, VAS DEFERENS, URETHRA: EJACULATION • ROUTE OF EXIT OF SPERM • DUCTUS DEFERNS STORES SPERM • DURING EMMISSION PHASE OF EJACULATION SPERM ARE EMPTIED INTO URETHRA BY SYMPATHETICALLY INDUCED CONTRACTIONS • MOTOR NEURON INDUCED CONTRACTIONS OF SKELETAL MUSCLES AT BASE OF PENIS EXPELL THE SEMEN DURING EXPULSION PHASE OF EJACULATION • EJACULATION IS A PART OF ORGASM

ANATOMY OF THE FEMALE REPRODUCTIVE SYSTEM • • VAGINA UTERUS CERVIX CLITORIS LABIA OVARIES OVIDUCTS

VAGINA • ENTRANCE TO UTERUS • PLACE WHERE PENIS INSERTS TO DEPOSIT SPERM • MUSCULAR, EXPANSIBLE TUBE

UTERUS • MAINTAINS FETUS DURING PREGNANCY • MUSCULATURE CONTRACTS TO EXPEL FETUS AT BIRTH

CERVIX • LOWEST PORTION OF THE UTERUS • PROJECTS INTO VAGINA • CERVICAL CANAL SERVES AS PATHWAY FOR SPERM DURING SEXUAL INTERCOURSE • PASSAGWAY FOR DELIVERY OF BABY FROM UTERUS

CLITORIS • ERECTILE TISSUE ANALOGOUS TO PENIS IN MALE • SENSITIVE AND EROTIC • AT FOLD OF LABIA MINORA

LABIA • • SKIN FOLDS MAJORA- OUTER MINORA-INNER AROUND VAGINAL AND URETHRAL OPENINGS

OVARIES • • FEMALE GONADS IN ABDOMEN PRODUCE OVA SECRETE ESTROGEN AND PROGESTERONE

OVIDUCTS • • LINK OVARIES TO UTERUS FALOPIAN OR UTERINE TUBES PICK UP OVA AT OVULATION SITE FOR FERTILIZATION

SEXUAL INTERCOURSE • COITUS OR COPULATION • AT SOME POINT PENIS IS INSERTED INTO VAGINA • SEXUAL RESPONSE CYCLE

THE FOUR PHASES OF SEXUAL CYCLE • • EXCITEMENT PLATEAU ORGASM RESOLUTION

EXCITEMENT • CAN BE INITIATED PHYSICALLY (TACTILE STIMULI)AND/OR PSYCHOLOGICALLY • CLITORIS, SURROUNDING PERINEAL AREA AND PENIS ARE PRIMARY AREAS FOR THIS • OTHER SENSITIVE AREAS MAY CONTRIBUTE IF STIMULATED, BREASTS, TESTICLES, ETC. • ERECTION OF PENIS AND CLITORIS RESULT (CLITORIS IS A HOMOLOGUE OF THE PENIS) • LUBRICATION FROM VAGINAL CAPILLARIES, GLANDS AT OPENING OF VAGINA AND PENIS PREPARE FOR INTERCOURSE

PLATEAU • INTENSIFICATION OF CHANGES DURING EXCITEMENT PHASE • HEART RATE AND BREATHING CHANGES • MUSCLE TENSION INCREASES • VAGINA TIGHTENS AROUND PENIS HEIGHTENING SENSATION • UTERUS RAISES UPWARD CREATING SPACE FOR EJACULATE

MALE ORGASM • RHYTHMIC CONTRACTIONS DURING SEMEN EXPULSION • INVOLUNTARY RHYTHMIC THROBBING OF PELVIC MUSCLES • BREATHING AND HEART RATE INCREASED • EMOTIONAL RESPONSE: RELEASE AND COMPLETE GRATIFICATION • RESOLUTION PHASE INVOLVES SYMPATHETIC VASOCONSTRICTION • A REFRACTORY PERIOD PREVENTS MULTIPLE ORGASMS IN THE MALE

EPIDIDYMUS, VAS DEFERENS, URETHRA: EJACULATION • ROUTE OF EXIT OF SPERM • DUCTUS DEFERNS STORES SPERM • DURING EMMISSION PHASE OF EJACULATION SPERM ARE EMPTIED INTO URETHRA BY SYMPATHETICALLY INDUCED CONTRACTIONS • MOTOR NEURON INDUCED CONTRACTIONS OF SKELETAL MUSCLES AT BASE OF PENIS EXPELL THE SEMEN DURING EXPULSION PHASE OF EJACULATION • EJACULATION IS A PART OF ORGASM

FEMALE ORGASM • PARALLELS THAT IN MALES WITH TWO EXCEPTIONS • NO COUNTERPART TO EJACULATION • NO REFRACTORY PERIOD-MULTIPLE ORGASMS POSSIBLE

SEX DETERMINATION AND DIFFERENTIATION • • SEX CHROMOSOMES X AND Y 22 PAIRS AUTOSOMAL 1 PAIR DETERMINES SEX: XX OR XY FEMALE REPRODUCTIVE TRACT AND EXTERNAL GENETALIA DEVELOP REGARDLESS • TESTOSTERONE PRODUCES MALE CHARACTERISTICS • EVIDENT AFTER 10 TO 12 WEEKS

MALE REPRODUCTIVE PHYSIOLOGY • DEPENDS ON TESTOSTERONE • TESTICULAR LEYDIG CELLS SECRETE TESTOSTERONE • TESTES DESCEND AND PASS OUT OF ABDOMINAL CAVITY

TESTOSTERONE: BEFORE BIRTH • BEFORE BIRTH: MASCULINIZES REPRODUCTIVE TRACT AND EXTERNAL GENETALIA • DESCENT OF TESTES • CEASES AT BIRTH • RETURNS AT PUBERTY

PUBERTY IN THE MALE • USUALLY 10 -14 YEARS OLD • ENDOCRINE, PHYSICAL, AND BEHAVIORAL • LEYDIG CELLS “AWAKE”

TESTOSTERONE: AT PUBERTY • SPERMATOGENESIS • ACCESSORY SEX GLANDS ENLARGE AND BECOME SECRETORY • PENIS AND SCROTUM ENLARGE • LIBIDO

EFFECTS OF TESTOSTERONE ON SECONDARY SEX CHARACTERISTICS • • HAIR GROWTH PATTERN DEEP VOICE THICK SKIN MALE BODY CONFIGURATION

OTHER EFFECTS OF TESTOSTERONE • • BONE GROWTH PROTEIN ANABOLIC EFFECT EVENTUALLY STOPS BONE GROWTH AGGRESSIVE BEHAVIOR(IN ANIMALS) • MALE MENOPAUSE

CONTROL OF TESTICULAR FUNCTION HYPOTHALAMUS GRH + ANTERIOR PITUITARY FSH TESTES SERTOLI CELL LH LEYDIG CELL SPERMATOGENESIS INHIBIN TESTOSTERONE

FEMALE REPRODUCTIVE PHYSIOLOGY • • • CYCLIC OOGENESIS FERTILIZATION PREGNANCY DELIVERY MENOPAUSE

THE OVARIAN CYCLE • • FOLLICULAR PHASE LEUTEAL PHASE ONLY INTERRUPTED BY PREGNANCY ENDS AT MENOPAUSE

FOLLICULAR PHASE • PRIMARY OOCYTE IS IN A PREPARATORY PHASE • FIRST MEIOTIC DIVISION • OVULATION • ESTROGEN SECRETED FROM FOLLICLE

LEUTEAL PHASE • AFTER OVULATION • DEVELOPMENT OF CORPUS LUTEUM • SECRETES PROGESTERONE AND ESTROGEN • DEGENERATES AFTER 2 WEEKS IF NOT FERTILIZED

IF NOT FERTILIZED • CORPUS LEUTEUM DEGENERATES • ESTROGEN AND PROGESTERONE LEVELS FALL • MENSTRUAL PHASE INVOLVES SLOUGHING OF PREPARED ENDOMETRIUM • NEW CYCLE STARTS-NEW FOLLICLES DEVELOP AND BEGIN SECRETING ESTROGEN

CONTROL OF FSH AND LH SECRETION DURING FOLLICULAR PHASE HYPOTHALAMUS GRH + ANTERIOR PITUITARY FSH LH OVARY INHIBIN LOW LEVELS OF ESTROGEN

CONTROL OF LH SURGE AT OVULATION HYPOTHALAMUS GNRH + ANTERIOR PITUITARY FSH LH OVARY MATURE FOLLICLE OVULATION HIGH LEVELS OF ESTROGEN

FEEDBACK CONTROL DURING LUTEAL PHASE HYPOTHALAMUS GNRH + ANTERIOR PITUITARY LH OVARY CORPUS LUTEUM MODERATE LEVELS OF ESTROGEN HIGH LEVELS OF PROGESTERONE

FERTILIZATION • • • IN OVIDUCT SPERM DEPOSITED IN VAGINA AT EJACULATION TRAVEL TO OVIDUCT TAKES A LITTLE OVER 1/2 HOUR CERVICAL CANAL IS OPEN DUE TO ESTROGEN BEING HIGH AND REMAINS OPEN TWO TO THREE DAYS SPERM ENTER UTERUS AND ARE CHURNED AROUND WHEN REACH OVIDUCT, SMOOTH MUSCLE CONTRACTIONS PROPELL THEM ONWARD MATURE EGG RELEASES A CHEMOTACTIC AGENT OUT OF SEVERAL HUNDRED MILLION ONLY A FEW THOUSAND MAKE IT TAIL OF SPERM MANEUVERS IT FOR FINAL PENETRATION

HORMONES OF PREGNANCY • PLACENTA IS ORGAN OF EXCHANGE • PLACENTA SECRETES HUMAN CHORIONIC GONADOTROPIN (HCG)PROLONGS LIFE OF CORPUS LUTEUM • ESTROGEN AND PROGESTERONE LEVELS EVEN HIGHER NOW • AFTER 10 WEEKS PLACENTA TAKES OVER

PARTURITION • • POSITIVE FEEDBACK CERVICAL DILATION DELIVERY OF PLACENTA

LACTATION • MAMMARY GLANDS OR BREASTS • MILK PRODUCING GLANDS AND FAT • ACTION OF ESTROGEN AND PROGESTERONE IS TO PREPARE GLANDS DURING PREGNANCY • ALSO BLOCK PROLACTIN’S STIMULATION • OXYTOCIN-MILK EJECTION • SUCKLING TRIGGERS OXYTOCIN RELEASE