PSYCH 210 - MALE SEXUAL ANATOMY (CHAPTER 5)

ACCESSORY GLANDS: SEMINAL VESICLES

1. SEMINAL VESICLES = DOESNTTT STORE SEMEN , SECRETES A FLUID THAT CONTAINS A FRUCTOSE/SUGAR & PROSTAGLANDINS . FLUID FROM SEMINAL VESICLES MAKE UP 70% OF THE VOLUME OF SEMEN -LOCATION OF SEMINAL VESICLES: DIRECTLY BEHIND BLADDER A. EJACULATORY DUCTS = FORMED BY LEFT AND RIGHT SEMINAL VESICLES THAT COMBINE WITH THE RIGHT AND LEFT VAS DEFERENTIA -INSIDE EJACULATORY DUCTS: SPERM MIX WITH FLUID FROM SEMINAL VESICLES 2. PROSTAGLANDINS = LOCATED IN FLUID SECRETED BY SEMINAL VESICLES , ENABLES THE MOTILITY AND VIABILITY OF THE SPERM , IS A HORMONE!!!!!! THAT ACT AS CHEMICAL MESSENGERS -ALSO NATURALLY PRESENT IN FEMALES: BRINGS UTERINE CONTRACTIONS DURING MENSTRUATION AND CHILDBIRTH -SPERM CONTAINS HIGH CONCENTRATION OF PROSTAGLANDINS: THEREFORE, DOCTORS WILL RECOMMEND SEXUAL INTERCOURSE TO TRIGGER LABOR IN PREGNANT WOMEN

THE TESTICLES

1. THE TESTICLES = THE MALE GONADS (IE: REPRODUCTIVE GLANDS) , 2 KEY REPRODUCTIVE FUNCTIONS OF THE TESTICLES ARE (1) PRODUCE SPERM/SPERMATOZOA (2) PRODUCE SEX STEROIDS WEIGHT OF EACH TESTICLE = 0.4-0.5 OUNCES A. SPERM/SPERMATOZOA = PRODUCED BY TESTICLES B. SPERMATOGENESIS = PROCESS OF SPERM PRODUCTION IN TESTES IN MALES (BEGINS IN SEMINIFEROUS TUBULES, MIGRATE TO LUMEN ONCE MATURED, Although sperm achieve partial motility during this process, it is not until they are combined with other secretions that make up semen that they become fully capable of fertilizing an ovum once inserted into the female body) (UNLIKE FEMALES WHO ARE BORN WITH ENTIRE SUPPLY OF OVA) =MALES CONSTANTLY PRODUCE SPERM THE STEPS OF SPERMATOGENESIS: (1) BEGINS IN SEMINIFEROUS TUBULES (2) MIGRATE TO LUMEN ONCE MATURED, (3) MATURE SPERM MOVE FROM LUMEN TO EPIDIDYMUS (remains in tube located in epididymis for about one week, becomes more concentrated here until it forms a paste-like mass, sperm matures during this period until theyre partially able to move) (4) AFTER 1 WEEK, SPERM MOVES UP INTO BASE OF VAS DEFERENS (where it remains in storage until ejaculation) (ejaculation = consists of a series of muscular contractions will push the sperm up the vas deferens, up through the spermatic cord, up over the bladder in the abdomen, and finally down toward the ejaculatory duct.) (5) In the ejaculatory ducts, sperm mix with fluid from the seminal vesicles. Despite their name, the seminal vesicles do not store semen. Instead, they secrete a fluid that contains fructose (a sugar) as well as prostaglandins, which enable the motility and viability of the sperm. Fluid from the seminal vesicles makes up about 70% of the volume of semen. (6) After mixing with fluid from the seminal vesicles, sperm travel from the two ejaculatory ducts into the urethra where the ejaculatory ducts merge. Here, they mix with fluid from the prostate gland. Prostate fluid comprises about 30% of semen and controls its coagulation to ensure that clots do not form. The fluid is alkaline, which serves to maintain sperm's viability. It also helps to counteract the naturally acidic environments of the urethra and vagina. C. SEMINIFEROUS TUBULES = A VERY FINE/TWISTY NETWORK INSIDE THE TESTICLE -WALLS OF SEMINIFEROUS TUBULES: LOCATION OF WHERE DEVELOPMENT OF SPERM (SPERMATOGENESIS) BEGINS!!!! D. LUMEN = TUBES WHERE MATURE SPERM MIGRATE TO E. TESTOSTERONE = A SEX STEROID!!! , PRODUCED BY INTERSTITIAL CELLS -INTERSTITIAL CELLS: LOCATED IN BETWEEN SEMINIFEROUS TUBULES, RESPONSIBLE FOR MAKING SEX STEROIDS ------------------------------------- PRACTICE QUESTION Which of the following statements about the testicles is false? a Sperm production begins in the cell lining of the seminiferous tubules. b Interstitial cells between the seminiferous tubules produce testosterone. c As sperm mature, they migrate from the seminiferous tubules into the lumen. d Once sperm have matured sufficiently to reach the lumen, they are fully mobile.

DISORDERS OF THE TESTICLES

•DISORDERS OF THE TESTICLES 1. TESTICULAR CANCER = OCCURS WHEN CANCER CELLS BEGIN TO GROW UNCONTROLLABLY INTO A TUMOR IN ONE OR BOTH TESTES =DISEASE OF THE YOUNG!!!!!!!! A. DETECTION = PAINLESS LUMP IN TESTICLES =USUALLY DETECTED BY MALES THEMSELVES OR PARTNERS RATHER THAN MEDICAL EXAMINATION B. SYMPTOMS OF TESTICULAR CANCER: -A LUMP (may or may not be accompanied by painful swelling) -DULL ACHE//HEAVY SENSATION IN LOWER ABDOMEN C. MOST OFTEN AFFECTS MALES BETWEEN 15-35 D. RISK FACTORS OF TESTICULAR CANCER: -TESTICLES THAT DONT INITIALLY DESCEND AT BIRTH -OTHER TESTICULAR ABNORMALITIES -KLINEFELTER SYNDROME E. TREATMENTS OF TESTICULAR CANCER: =HIGHLY TREATABLE IF DETECTED EARLY -SURGICAL REMOVAL OF TESTICLE/TESTES (MOST COMMON) -RADIATION -CHEMOTHERAPY =SINCE TREATMENT INTERFERES W FERTILITY, SOME MEN CONSIDER DEPOSITING SEMEN SAMPLES BEFORE TREATMENT F. LANCE ARMSTRONG =high-profile case of testicular cancer =PROFESSIONAL ROAD CYCLIST =famous for winning the Tour de France seven times between 1999 and 2005. I =Armstrong went on to found LiveStrong, a foundation that raises awareness for cancer and has raised over $500 million to help cancer victims. =Unfortunately, in 2010, Armstrong was accused and later found guilty, of using performance-enhancing drugs and his wins going back to 1998 were all voided ---------------------------------------------- •NON-CANCEROUS DISORDERS OF THE TESTICLES 2. EPIDIDYMITIS = inflammation of the epididymis (the coiled tube at the back of the testicle that stores and carries sperm) due to infection from bacteria, including STI. -Epididymitis and orchitis often co-occur. 3. ORCHITIS = inflammation of the testicle due to infection. -Epididymitis and orchitis often co-occur. -The virus that causes mumps also can cause orchitis. 4. HYDROCELE = usually harmless swelling of the testicle that occurs in reaction to fluid becoming trapped around the testicle membranes. =Hydroceles usually resolve on their own or can be drained by a doctor. 5. VARIOCELE = enlargement of the veins around the testicle, which some males describe as feeling like a "bag of worms." Again, these usually don't need to be treated and will resolve on their own.

LEARNING OBJECTIVES

-Identify the location and function of the male reproductive/sexual structures, including the penis and scrotum. -Identify the location function of the male reproductive accessory glands including the seminal vesicles, prostate, and bulbourethral gland. -Understand the mechanics of ejaculation -Attain an understanding of male sexual health, including types of common cancers and disorders that affect the penis.

ACCESSORY GLANDS

1. ACCESSORY GLAND: VAS DEFERENS A. FUNCTION: RECEIVES SPERM FROM EPIDIDYMUS AFTER ABOUT 1 WEEK > STORES SPERM UNTIL IMMEDIATELY BEFORE EJACULATION ---------------------------------- After about a week, sperm move from the epididymis up into the base of the vas deferens, where they remain in storage until immediately before ejaculation. At this point, a series of muscular contractions will push the sperm up the vas deferens, up through the spermatic cord, up over the bladder in the abdomen, and finally down toward the ejaculatory duct.

BULBOURETHRAL GLANDS//COWPER'S GLANDS

1. BULBOURETHRAL GLANDS//COWPER'S GLANDS = ARE TWO PEA-SIZED GLANDS LOCATED BELOW PROSTATE GLAND + SECRETES A CLEAR, ALKALINE, MUCOUS FLUID INTO URETHRA THATS... =RELEASED SOMETIME BETWEEN ERECTION & EJACULATION, =APPEARS AT TIP OF PENIS AS A CLEAR/SLIPPERY DROP OF LIQUID, =REFERRED TO AS "PRE-CUM"!!!!! GIVEN ITS TIMING A. SECRETIONS FROM BULBOURETHRAL GLANDS = NOTTTTTTTT PART OF SEMEN BUUUUUUT DO PLAY IMPORTANT ROLE IN FERTILIZATION =HELPS NEUTRALIZE THE NATURALLY ACIDIC ENVIRONMENTS OF THE MALES URETHRA AND FEMALES VAGINA (TO ENSURE VIABILITY OF SPERM) B. DOES NOTTTT CONTAIN SPERM BUT EASILY ABSORBS SPERM LEFT IN URETHRA FROM PRIOR EJACULATIONS =Although fluid from the bulbourethral glands does not contain sperm, it easily absorbs sperm left in the urethra from recent prior ejaculations. C. CONSEQUENTLY, ITS SECRETIONS/PRE-CUM CAN STILL CAUSE PREGNANCY!!!!!!!! IF IT COMES INTO CONTACT WITH FEMALE GENITALS OR CERVICAL MUCUS. ------------------------------------------------- PRACTICE QUESTIONS Which of the following is true about fluid from the bulbourethral gland? a It always contains sperm. b It is incapable of causing pregnancy. c It is released immediately after ejaculation. d None of the above are true

EJACULATION//EMISSION

1. EJACULATION//EMISSION = CAUSED BY A SERIES OF CONTRACTIONS OF THE MUSCLES SURROUNDING THE URETHRA AND PELVIC FLOOR 2. PROCESS OF EJACULATION: Sperm travels up from the base of the vas deferens. Sperm are pushed around the top of the bladder. Sperm are mixed with seminal fluid in the ejaculatory ducts. Sperm is mixed with fluid from the prostate gland. Semen is emitted through the urethra and out of the penis. (1) IMMEDIATELY PRIOR TO EMISSION, FLUIDS FROM THE VAS DEFERENS, SEMINAL VESICLES AND PROSTATE GLAND ARE EXPELLED INTO THE URETHRA CREATING SEMEN. (2) THE URETHRAL SPHINCTER AT THE BASE OF THE BLADDER CONSTRICTS, PREVENTING BACKFLOW AND FORCING SEMEN IN ONE DIRECTION—OUT OF THE BODY (3) ONCE EJACULATION BEGINS, IT IS EXPERIENCED AS AN INEVITABLE PULSING SENSATION AT THE BASE OF THE PENIS. (4) EACH PULSE LASTS ABOUT 0.8 SECONDS AND FORCEFULLY PUSHES SEMEN FROM THE URETHRA IN A SERIES OF SPASMS THAT DECREASE IN INTENSITY.

THE EPIDIDYMIS

1. EPIDIDYMUS = A CURVED STRUCTURE THAT ATTACHES TO THE BOTTOM AND TOP SURFACE OF THE TESTICLE , MATURE SPERM MIGRATE FROM LUMEN TO EPIDIDYMUS A. CONTAINS ONE/VERY LONG EXTREMELY CONVOLUTED TUBE =SPERM REMAINS IN THIS TUBE/TUBULE FOR APPROXIMATELY ONE WEEK =BECOMES MORE CONCENTRATED HERE UNTIL THEY FORM A PASTE-LIKE MASS =SPERM MATURES DURING THIS PERIOD UNTIL THEYRE PARTIALLY ABLE TO MOVE

PENILE DISORDERS

1. PENILE DISORDER #1: BALANTIS = INFLAMMATION OF THE GLANS // Swollen glans as a result of infection. A. MOST FREQUENT IN UNCIRCUMCISED MALES B. CAUSE: NOT PROPERLY CLEANING SMEGMA, WHICH CAN CAUSE IRRITATION OR AN INFECTION LIKE BALANTIS -SMEGMA: A MUCUS-LIKE SUBSTANCE SECRETED BY TYSON'S GLANDS (LOCATED BETWEEN FORESKIN & HEAD OF PENIS) =Smegma is easily cleaned by retracting the foreskin during bathing. 2. PENILE DISORDER #2: PHIMOSIS = OCCURS WHEN FORESKIN CANNOT BE PULLED BACK ENOUGH TO EXPOSE THE GLANS // Foreskin cannot be retracted over glans. (OPPOSITE OF PARAPHIMOSIS) A. EXPERIENCED BY MANY BABIES + SOME TEENAGE BOYS B. ONLY SERIOUS MEDICAL PROBLEM IF PREVENTS FLOW OF URINE C. BALANTIS MAY CAUSE PHIMOSIS IN ADULT MALES!!!!!!! =^^^MORE SERIOUS CONDITION (CAN BE PAINFUL + REQUIRES MEDICAL ATTENTION) 3. PENILE DISORDER #3: PARAPHIMOSIS = OCCURS WHEN FORESKIN BECOMES TRAPPED BEHIND THE GLANS, INSTEAD OF BEING IN FRONT OF GLANS // Foreskin is trapped behind corona and cant be pulled back over the glans. (OPPOSITE OF PHIMOSIS) A. IS MOREEEEEE DANGEROUS THAN PHIMOSIS -REASON: CAN LIMIT BLOOD SUPPLY TO GLANS (( WHICH CAN CAUSE TISSUE DEATH )) 4. PENILE DISORDER #4: PEYRONIE'S DISEASE = INVOLVES UNNATURAL CURVATURE OF PENIS, USUALLY CAUSED BY SCAR TISSUE IN CORPUS CAVERNOSA A. THIS SCAR TISSUE.......... =USUALLY RESULT OF TRAUMA =CAN CAUSE PAIN =PREVENT PENETRATIVE SEX (EXTREME CASES) B. REQUIRES SURGICAL REPAIR =Keep in mind though that many males have mild curvature in their penises and that this is completely normal. C. THERE HAVE BEEN RECENT MEDICAL ADVANCES IN TREATMENT OF PEYRONIES

PENIS SIZE

1. PENIS SIZE A. SATISFACTION RATE = ONLY 55% OF MEN ARE SATISFIED WITH THEIR PENIS SIZE =GIVEN PROMINENCE OF PENIS, MANY MEN MAY EXPERIENCE ANXIETY ABOUT ITS SIZE OR GENERAL APPEARANCE B. ROLE OF MEDIA AND MASCULINITY What about men concerned that their penis is smaller than average? Much of this anxiety is triggered by false perceptions put forth once again by the media. -REASON/ROLE #1: SIZE INSECURITY FUELED BY PORN & OTHER MEDIA SOURCES THAT EXAGGERATE ACTUAL SIZE -REASON/ROLE #2: MEDIA SHOWS MANY MESSAGES EQUATING PENIS SIZE WITH POWER & MASCULINITY C. ERECTION SIZE DID NOT DIFFER WITH AGE, RACE OR SEXUAL ORIENTATION According to a 2014 study completed at Indiana University that focused on 1661 sexually active males, the average erect penis length is 5.6 inches The study found that participants' erect penises ranged from 1.6 inches to 10.2 inches and averaged 4.8 inches in circumference. Perhaps unsurprisingly, erection size did not differ with age, race or sexual orientation. D. DIVERSITY EXISTS ACROSS ALL MALES AND EVERY PENIS SIZE = =in their flaccid state, penises come in an extremely wide range of shapes, colors, and sizes. =Dodsworth also gives an interesting account of the incredible anxiety and inadequacy that so many men feel regarding the size of their penis, and how she hopes to help them overcome this by illustrating that there is no one perfect shape or size. E. HUGE DIVERSITY IN HOW MUCH A PENIS GROWS FROM FLACCID TO ERECT STATE =WHERE TERM, "GROWERS" VS. "SHOWERS" COME FROM -GROWERS: PENIS SIZE CHANGES A GREAT DEAL DURING AN ERECTION//WHEN CHANGING FROM FLACCID O ERECT STATE -SHOWERS: PENIS SIZE ONLY CHANGES SMALL AMOUNT DURING AN ERECTION//WHEN CHANGING FROM FLACCID O ERECT STATE =^^^DIFFERENCES DUE TO GENETICS + SKIN ELASTICITY

ACCESSORY GLANDS: PROSTATE GLAND

1. PROSTATE GLAND // PARAURETHRAL GLAND = PRODUCES A FLUID THAT MIX WITH SPERM IN THE URETHRA WHERE THE EJACULATORY DUCTS MERGE -PROSTATE FLUID: COMPRISES ABOUT 30% OF SEMEN & CONTROLS ITS COAGULATION TO ENSURE BLOOD CLOTS DONT FORM >>>> IS ALKALINE (MAINTAINS SPERM'S VIABILITY + COUNTERACTS NATURALLY ACIDIC ENVIRONMENT OF VAGINA/URETHRA) -LOCATION: MIDLINE OF MALE BODY, DIRECTLY BENEATH BLADDER =TYPICALLY SIZE OF WALNUT =IS EQUIVALENT TO SKENE'S GLAND IN FEMALE BODY ------------------------------------------------- 2. PROSTATE CANCER =1 IN 9 MALES DIAGNOSED =MOST COMMON CANCER AMONG MALES =AFFECTS MALES OVER 50 A. TREATMENT = HIGHLY TREATABLE IF DETECTED EARLY =5 YEAR SURVIVAL RATE OF CLOSE TO 99% -SURGICAL REMOVAL OF ENTIRE PROSTATE & NEARBY LYMPH NODES -RADIATION THERAPY -TESTOSTERONE-BLOCKING DRUGS B. SYMPTOMS = DIFFICULTY URINATING, BLOOD IN URINE/SEMEN, PAIN IN LOWER BACK OR HIPS =OFTEN NO SYMPTOMS (BC IT GROWS SO SLOWLY) ------------------------------------------------- 3. PROSTATITIS = NON-CANCEROUS CONDITION THAT CAN BE EITHER CHRONIC OR ACUTE -INVOLVES: INFLAMMATION OF PROSTATE, PAIN DURING EJACULATION OR URINATION, ONGOING PAIN IN LOWER BACK OR PELVIS =FREQUENTLY CAUSED BY URINARY TRACT INFECTION (UTI) ------------------------------------------------- 4. BENIGN PROSTATIC HYPERPLASIA ("ENLARGED PROSTATE") = COMMON CONDITION WHERE PROSTATE CONTINUES TO GROW SLOWLY THROUGHOUT ADULT LIFE =PRIMARILY AFFECTS MALES OVER 60 =CAN EVENTUALLY CONSTRICT URETHRA AS IT PASSES THRU THE PROSTATE CAUSING WEAK URINE FLOW, URGENCY/HIGH FREQUENCY IN URINATION

THE SCROTUM

1. SCROTUM = ANOTHER MALE EXTERNAL GENITALIA (IN ADDITION TO PENIS) , CAN BE VIEWED FROM OUTSIDE OF MALES BODY INSIDE THE SCROTUM = TWO TESTICLES (GIVES SCROTUM SHAPE & CAN BE EASILY FELT WITHIN SCROTAL SAC) -FUNCTION OF THE SCROTUM: the function of the scrotum is to protect the testes from temperature fluctuations + HOLD THE TESTES A SPERMATIC CHORD = A LOOSE BUNDLE OF STRUCTURES!!!!!!! THAT EACH TESTICLE USES TO CONNECT TO IMPORTANT INTERNAL ORGANS B. VAS DEFERENS = LOCATED WITHIN SPERMATIC CORD/INGUINAL CANAL , CARRIES MATURE SPERM UP FROM THE TESTICLES + NOURISHES THE TESTICLES VIA A VAST SUPPLY OF ARTERIES AND VEINS connects up to the body through the spermatic cord, THE VAS DEFERENS & SPERMATIC CORD = PERFORM CRITICAL FUNCTIONS IN REPRODUCTION, YET REMAIN SLIGHTLY VULNERABLE IN THEIR ARRANGEMENT OUTSIDE THE BODY -TESTICULAR TORSION: BECAUSE OF VULNERABLE POSITIONING OF VAS DEFERENS & SPERMATIC CORD OUTSIDE OF BODY, CRUNCHING OR TWISTING OF THIS AREA CAN BE EXTREMELY PAINFUL AND RESULT IN SIGNIFICANT DAMAGE C. INGUINAL CANAL = A TUBE THAT CONNECTS THE SPERMATIC CORD THROUGH THE ABDOMINAL WALL AND INTO THE GROIN D. CREMASTER MUSCLE = WRAPS AROUND THE SPERMATIC CORD , IS POSITIONED LIKE A SLING FOR THE TESTICLES muscle is responsible for lowering and raising the testicles in order to keep them at the right temperature for producing sperm. -PRIMARY FUNCTION OF CREMASTER MUSCLE: KEEP SPERM AT IDEAL TEMPERATURE ((ABOUT 7 DEGREES BELOW THAT OF THE REST OF THE BODY)) -IN RESPONSE TO COLD TEMPERATURES: the cremaster muscle contracts, warming sperm by bringing them in closer to the body. -IN RESPONSE TO WARMER TEMPERATURES: the cremaster muscle relaxes, allowing the testicles to drop away from the body and thereby cooling the sperm.

SEMEN (EJACULATE)

1. SEMEN//EJACULATE = TYPICALLY THICK, CLOUDY, AND OFF-WHITE IN COLOR , A. COMPONENTS THAT MAKE UP SEMEN/EJACULATE: -30% PROSTATIC FLUID -70% SEMINAL FLUIDS -LESS THAN 1% (ABOUT 300 MILLION) SPERM ------------------------------------------------- 2. EACH SPERM CONSISTS OF A SINGLE-CELL THAT IS TADPOLE-LIKE IN APPEARANCE A. THE STRUCTURE OF A SPERM (TADPOLE-LIKE IN APPEARANCE) -HEAD: CONTAINS THE NUCLEUS -FLAGELLUM: THE TAIL!!!!, PROPELS SPERM FORWARD -ACROSOME: SURROUNDS TOP OF HEAD OF SPERM + CONTAINS IMPORTANT RECEPTORS & ENZYMES THAT FACILITATE FERTILIZATION OF AN OVUM -MIDPIECE: LOCATED AT PART OF FLAGELLUM CLOSEST TO HEAD + IS TIGHTLY WOUND WITH MITOCHONDRIA THAT SUPPLY ENERGY FOR THE SPERM ------------------------------------------------- PRACTICE QUESTIONS On its own, seminal fluid contains which of the following? a Fructose b Prostaglandins c Sperm d A and B ( but not C) The prostate gland releases fluid that: a Is released from the ejaculatory ducts. b Contains fructose. c Prevents semen from coagulating. d Contains sperm. Which of the following is false regarding prostatic cancer? a It is the most common type of non-skin cancer in males. b It mostly affects males in their 20s and 30s. c It is recommended that males over 40 receive regular prostate checks so as to enable early detection. d When caught early, it is usually, but not always, curable. Surrounding the top of the head of a sperm is a(n) ________ACROSOME____________, which facilitates fertilization of an ovum by containing various enzymes and receptor sites. The midpiece of the sperm is located at the top of the ___________FLAGELLUM______________, near the head of the sperm.

THE PENILE SHAFT

1. SHAFT = CONTAINS 3 STRUCTURES ALL BOUND TOGETHER BY CONNECTIVE TISSUE -THE 3 STRUCTURES THAT MAKE UP THE SHAFT: CORPORA CAVERNOSA, CORPUS SPONGIOSUM, URETHRA A. CORPORA CAVERNOSA = TWO!!!! OF THESE LIE ON EITHER SIDE OF THE PENIS, HARDENS DURING AROUSAL//STIFFENS DURING ERECTION =CONTROLS THE ANGLE!!!!!!! OF MALE'S ERECTION WHILE ALLOWING FOR PENETRATION B. CORPUS SPONGIOSUM = DESCENDS DOWN THE CENTER OF PENIS & GLANS, ENLARGES DURING ERECTION (CONTRIBUTING TO SIZE) -PENILE BULB: LOCATED AT END OF PENIS (CLOSEST TO MALE'S BODY) + IS A ROUNDED MASS OF ERECTILE TISSUE FORMED BY THE CORPUS SPONGIOSUM -CRURA: LOCATED WITHIN PENILE BULB + TWO CORPORA CAVERNOSA DIVERGE/SEPARATE INTO TWO CRURA!!!! (JUST AS THEY DO IN FEMALE CLITORIS) C. THE PELVIC FLOOR MUSCLES IN MEN ALSO PLAY AN IMPORTANT ROLE IN SEXUAL FUNCTION (SIMILAR TO WOMEN) -ISCHIOCARVERNOSUS: PELVIC FLOOR MUSCLE THAT AFFECTS THE ANGLE OF A MALE'S ERECTION + ALLOWS FOR VOLUNTARY MOVEMENT OF ERECT PENIS -BULBOSPOGIOSUS AND PUBOCOCCYGEUS MUSCLES: PELVIC FLOOR MUSCLES INVOLVED IN THE PROCESS OF ORGASM & EJACULATION // CONTRACTS DURING ORGASM -KEGEL EXERCISES IN MEN: CAN ALSO BE PERFORMED LIKE WOMEN TO STRENGTHEN PELVIC FLOOR MUSCLES ((BENEFITS INCREASED EJACULATORY CONTROL + ORGASM STRENGTH))) D. URETHRA = RUNS THROUGH SHAFT OF PENIS + SERVES THE 2 FUNCTIONS OF (1) DISCHARGING SEMEN!!! AND (2) DISCHARGING URINE!!!! URINE NATURALLY MAKES URETHRA ACIDIC = HELPS CONTROL BACTERIA GROWTH URINE = HARMLESS, STERILE, NO STIs (therefore, can be safely enjoyed by some in sexual play aka "golden showers") =During sexual arousal, however, muscles at the base of the bladder contract in order to close off the passageway from the bladder into the urethra, which prohibits urine from being released during ejaculation. This can often create a confusing situation for males who wake up in the morning with both an erection and the need to urinate, yet lack the ability to urinate.

THE MECHANICS OF AN ERECTION

1. THE MECHANICS OF ERECTION A. GENITAL END-BULBS = A CLASS OF HIGHLY CONCENTRATED SENSORY NERVE ENDINGS (SIMILAR TO CLITORIS) The concentrated nerve endings near the surface of the penis that are highly sensitive to tactile stimulation are called: =ARE ESPECIALLY RESPONSIVE TO TACTILE STIMULATION DURING SEXUAL BEHAVIOR =ARE ESPECIALLY DENSE AROUND THE CORONA AND IN THE FRENULUM (EXPLAINS WHY THOSE AREAS ARE MOST EROTICALLY SENSITIVE PARTS OF PENIS) B. AUTONOMIC NERVOUS SYSTEM = ALL GENITAL RECEPTORS RELEVANT TO ERECTION ARE TRIGGERED BY A SPINAL REFLEX!!!!! + ARE PART OF THE AUTONOMIC NERVOUS SYSTEM!!!! =THEREFORE, MALES WHO HAVE SUFFERED SPINAL INJURIES IN WHICH THEIR SPINAL CORD IS SEVERED FROM BRAIN ARE STILL ABLE TO DEVELOP ERECTIONS ERECTION = NOT POSSIBLE FOR MALES WITH SEVERE SPINAL INJURIES (bc sometimes erections occur as a result of mental imagery/erotic thoughts) C. VASOCONGEST = REFERS TO WHEN BLOOD FLOWS INTO THE PENIS IN ORDER TO GROW ERECT =Within the corpora cavernosa are tiny spaces called sinusoids that fill with blood during erection. -IN FLACCID STATE: ARTERIES LEADING INTO SINUSOIDS REMAIN BLOCKED OFF -DURING ERECTION: ARTERIES OPEN IN ORDER TO POOL BLOOD INTO SINUSOIDS IN CORPUS CAVERNOSA D. PRIAPISM = IS A DANGEROUS CONDITION IN WHICH AN ERECTION IS SUSTAINED WHEN THERE IS NO STIMULATION OR WHEN STIMULATION HAS ENDED. =CAN CAUSE DAMAGE BECAUSE THE TISSUE IN THE PENIS HAS NO BLOOD FLOW E. VIAGRA = A DRUG USED TO TREAT ERECTILE DYSFUNCTION -HOW VIAGRA WORKS: TARGETS NITRIC OXIDE, A NEUROTRANSMITTER THAT CONTROLS THE OPENING AND CLOSING OF VEINS/ARTERIES (blood flow is needed for erection & climax) ----------------------------------------------- 2. WHAT CONTRIBUTES TO ERECTION/THE HYDRAULICS OF AN ERECTION Mechanically, erections involve a fascinating display of hydraulics. Within the corpora cavernosa are tiny spaces called sinusoids that fill with blood during erection. When the penis is In a flaccid state, the arteries leading into the sinusoids remain blocked off. During an erection's formative stage, these arteries open in order to pool blood into the corpora cavernosa. Meanwhile, the veins of the penis that carry blood out close, allowing for the penis to vasocongest and grow erect. As climax approaches, even more blood rushes into the penis, especially the glans. -------------------------------------------------- 3. NOCTURNAL ERECTIONS = REFERS TO PHENOMENON OF MALES EXPERIENCING ERECTIONS AT NIGHT WHEN THEY SLEEP (COMMON) A. WHAT HAPPENS = BLOOD CONTINUOUSLY POOLS IN AND OUT OF PENIS =MAY HELP OXYGENATE PENILE TISSUE + MAINTAIN ELASTICITY B. FREQUENTLY OCCURS DURING REM PHASE OF SLEEP (AKA PHASE WHEN VIVID DREAMS OCCUR) =DREAMS DONTTT NEED TO BE EROTIC FOR ERECTION C. AVERAGE = 3-5 TIMES PER NIGHT D. NOCTURNAL EMISSION = ORGASM AND EJACULATION DURING NOCTURNAL ERECTION =OCCURS ESPECIALLY DURING TEEN YEARS^^^^^^ =4 out of 5 males and 1 out of 4 females will experience an orgasm in their sleep at least once in their lives.

THE PENIS

1. THE PENIS =MORE PROTRUSIVE/NOTICEABLE THAN EXTERNAL FEMALE GENITALIA (makes more males feel insecure/familiar with their penises) = A. GLANS = HEAD OF PENIS, ON TOP OF PENIS SHAFT =SIMILAR TO CLITORIS B. CORONA = ENCIRCLES THE GLANS, IS A RIM OF TISSUE =ONE OF MOST EROTICALLY SENSITIVE AREAS OF PENIS =The corona and frenulum tend to be the most erotically sensitive areas of the penis. C. FRENULUM = ON UNDERSIDE OF PENIS, THE CORONA MOVES IN CLOSER TO THE TIP OF THE PENIS, CREATING A STRIP OF LOOSER SKIN CALLED THE FRENULUM =ONE OF MOST EROTICALLY SENSITIVE AREAS OF PENIS =The corona and frenulum tend to be the most erotically sensitive areas of the penis. D. FORESKIN = A LOOSE FOLD OF SKIN THAT PARTIALLY COVERS THE GLANS IN AN UNCIRCUMCISED PENIS -IN CHILDREN: FORESKIN SOMETIMES EXTENDS WELL PAST TIP OF GLANS & ACTS AS AN EXTENSION OF THE URETHRA ALLOWING URINE TO PASS THROUGH -IN MATURE ADULT MALES: FORESKIN CAN BE EASILY PULLED BACK TO EXPOSE THE GLANS & NATURALLY RETRACTS DURING AN ERECTION E. CIRCUMCISION = SURGICAL REMOVAL OF THE FORESKIN FROM THE PENIS, EXPOSING THE GLANS F. HEALTH BENEFITS OF CIRCUMCISION: -LOWER RATES OF STIs FROM VAGINAL SEX: HIV!! (50%-60%), HPV!! (30%, aka virus that causes cervical cancer), HSV!! (45%) -LOWER RATES OF HERPES -LOWER RATES OF PROSTATE CANCER -LOWER RATES OF URINARY TRACT INFECTIONS (UTIs) + INFANTILE URINARY TRACT INFECTIONS =NO EVIDENCE THAT CIRCUMCISION PROTECTS FEMALES

ACCESSORY SEXUAL STRUCTURES

There are many parts of the male body besides the penis that are related to sexual response but do not play a direct role in reproduction. Similar to females, the anus, perineum and nipples all play an important role in sexual response. -------------------------------- 1. THE ANUS = HAS SAME NERVE SUPPLY AS GENITALS >> DILATES IN RESPONSE TO STIMULATION AND CONTRACTS DURING AN ORGASM -LACKS LUBRICATING RESPONSE: MORE SUSCEPTIBLE TO TEARING + HIGHLY CAPABLE OF TRANSMITTING STIs 2. PERINEUM = LOCATED BETWEEN BASE OF PENUS AND ANUS >> CONSISTS OF FLAT AREA OF SKIN (SIMILAR TO FEMALE) =MANY MALES FIND THIS AREA TO BE EASILY AROUSED BY EROTIC TOUCH 3. NIPPLES = WIDE RANGE OF RESPONSES TO NIPPLE STIMULATION REPORTED (VARIES FROM INDIFFERENCE TO MODERATE PLEASURE TO ORGASM) -MALES OCCASIONALLY HAVE ADDITIONAL NIPPLES: CAN APPEAR ON ARMPIT, CHEST, ABDOMEN A. THIRD NIPPLE = SUPERNUMERARY NIPPLE, HAS NO REAL DEVELOPMENTAL SIGNIFICANCE =LEFTOVER ADAPTATION FROM EVOLUTIONARY ANCESTRY =OCCURS IN 1 IN 18 PEOPLE --------------------------------------- PRACTICE QUESTIONS Place the following components of ejaculation in their proper sequence. Sperm travels up from the base of the vas deferens. Sperm are pushed around the top of the bladder. Sperm are mixed with seminal fluid in the ejaculatory ducts. Sperm is mixed with fluid from the prostate gland. Semen is emitted through the urethra and out of the penis. During ejaculation, a sphincter ________BLADDER____________ in the closes off to prevent the backflow of semen, forcing it to exit the male's body. Which of the following is not considered to be an accessory sexual structure in the male body? a Nipples b Anus c Penis d Perineum