Chapter Four

1
Chapter Four

• Male Sexual Anatomy and Physiology

2
Agenda

• Discuss Male Sexual Reproductive System
• Describe Male Maturation Cycle
• Discuss Male Reproductive and Sexual Health

3
What do you think about the penis?

• On a blank sheet of paper, respond to the
  following
• The penis is
• Do not put your name on the paper, but turn it in.

4
The Male Sexual and Reproductive System

• External Sex Organs
• Internal Sex Organs
• Other Sex Organs

5
External Sex Organs

• Boys are typically more comfortable with their
  genitalia than girls
• Testes are visible (ovaries are internal)
• Penis is typically held during urination
• External sex organs
• Penis
• Scrotum

6
The Penis

• Contains urethra for urine and semen transport
• Becomes erect to better penetrate the vagina and
  deposit sperm near the os
• No bone, little muscle
• Composed of 3 cylinders of erectile tissue
• Corpora cavernosa (2)
• Corpus spongiosum (contains the urethra)

7

• Internal structure of the penis (side view)

8
The Glans Penis

• The conelike end of the penis
• Corona
• Frenulum
• Meatus
• Sensitive to stimulation

9
The Glans Penis

• Foreskin is a fold of skin that can cover part or
  all of the glans retracts over the corona during
  an erection
• Circumcision surgical removal of the foreskin
  most common male surgery in the U.S.
• Religious/cultural ritual
• Health reasons
• Medical value is questionable
• Women report greater sexual satisfaction with
  partners who have not been circumcised (OHara
  OHara, 1999)

10
Class Discussion

• Male Circumcision is the most common male
  surgical procedure in the U.S. but it doesnt
  seem to be medically necessary.
• Why do you think it remains so common?
• Discuss the finding from OHara Hara (1999)
  which reported that women experience greater
  sexual satisfaction with men who have not been
  circumcised.

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The Root of the Penis

• Extends into the body below the pubic bone
• Attached to internal pelvic muscles and can be
  felt in the perineum

12

• The male reproductive organs.

13
Erection

• Any type of stimulation perceived as sexual can
  cause an erection spinal reflex
• Erection also occurs during REM, possibly to keep
  the penis supplied with blood
• Nerve fibers open the arteries of the penis to
  allow blood to flow into the 3 cylinders
• Veins compress to prevent exit of blood
• Flaccid state returns when arteries constrict and
  the veins open to allow blood to flow out

14
The Scrotum

• Loose, wrinkled pouch beneath the penis
  containing the testicles
• Lightly covered with pubic hair
• Functions to keep the testicles 3C cooler than
  the bodys temperature to keep sperm viable
• Contains sweat glands
• Cremaster muscle moves the scrotum closer to or
  farther from the body (protects)

15
Internal Sex Organs

• Testes
• Epididymis
• Vas deferens
• Seminal vesicles
• Prostate gland
• Cowpers glands

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• The male reproductive organs.

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The Testicles

• Two egg-shaped glands in the scrotum
• 2 inches long, 1 inch diameter
• Typically one (usually the left) hangs a bit
  lower to allow sliding past rather than
  compression
• 2 primary functions
• Testosterone production
• Spermatogenesis (a/k/a sperm production)

18
Testosterone Production

• Testosterone is the most important male hormone
• Interstitial, or Leydig, cells in the testicles
  produce testosterone out of cholesterol

19
Spermatogenesis

• Seminiferous tubules produce and store sperm
• Sertoli cells (in the tubules) provide nutrition
  for the development of sperm
• Sperm production takes 72 days, but is constant
  and each male produces about 300 million sperm a
  day

20
The Ejaculatory Pathway

• Ejaculation physiological process where seminal
  fluid is powerfully expelled from the penis
• Pathway organs
• Vas deferens
• Seminal vesicles
• Prostate gland
• Cowpers glands

21
The Ejaculatory Pathway

• Vas deferens 18-inch tube that carries sperm
  from the testicles, combines fluids from other
  glands, and propels the sperm
• Seminal vesicles next to the ampulla of the vas
  deferens secretes a nutritional bath for
  traveling sperm 60-70 of the ejaculate volume
  joins the vas deferens to form the ejaculatory
  duct that passes into the prostate and then forms
  the urethra

22
The Ejaculatory Pathway

• Prostate gland walnut-sized gland beneath the
  bladder secretes a fluid that neutralizes the
  acidity of the vagina that would be lethal to
  sperm 25-30 of the ejaculates volume
• Cowpers (bulbourethral) glands 2 pea-sized
  glands next to the urethra, under the prostate
  contributes fluid that cleans the urethra of
  lethal acidic urine comprises the majority of
  the pre-ejaculatory fluid

23
Ejaculation

• Once the threshold is reached
• Epididymis, seminal vesicles, and prostate empty
  their fluids into the urethral bulb
• A sphincter closes off the bladder
• 5-15 contractions at the base of the penis
  squeeze the urethral bulb
• Ejaculate is expelled
• Orgasm
• Return to flaccid state

24
Ejaculate/Semen

• 2-5 milliliters of fluid
• 50-150 million sperm per milliliter
• Few sperm reach the ovum
• Sperm work together in order to fertilize the egg
• Semen coagulates upon ejaculation this helps it
  remain in the vagina and travel into the uterus
• 5-20 minutes later it thins out

25
Other Sex Organs

• Breasts mostly muscle and no functional
  purpose some men are sexually pleased when the
  nipples are stimulated
• Erogenous zones scrotum, testicles, anus
• Stimulation perceived as sexually exciting can
  determine what is erogenous to each person

26
The Male Maturation Cycle

• Male Puberty
• Andropause

27
Class Discussion

• Do you think most men are concerned with the size
  of their penis? Why or why not?
• Do you think there is a correlation between penis
  size and masculinity?
• If penis enlargement surgery was 100 effective,
  what percentage of men do you think would have
  the surgery?

28
Male Puberty

• Around 10 years of age, the hypothalamus starts
  to release gonadotropin releasing hormone (GnRH)
  which signals the pituitary to release FSH and LH
• At the testes, LH stimulates testosterone
  production the two combined and FSH stimulate
  sperm production (around 12 years)
• Negative feedback loop

29
Male Puberty

• Many organs and glands increase in size
  testicles, penis, epididymis, prostate, seminal
  vesicles, Cowpers glands
• Growth spurt initiated by testosterone levels
• Testosterone and DHT develop the secondary sex
  characteristics larger muscles and bones, pubic
  hair, thick and tough skin, deep voice, facial
  and chest hair, increased sex drive

30
Andropause

• Testosterone levels decrease about 1 per year
  after 40 years of age
• In the 70s and 80s, andropause occurs
• Andropause symptoms decreased spermatogenesis,
  thinner ejaculate, less ejaculatory force, libido
  decreases, fatigue, mood disturbances, decreased
  strength
• Controversy over hormone treatments

31
Male Reproductive and Sexual Health

• Diseases of the male reproductive organs
• Other conditions that affect the male
  reproductive organs
• Cancer of the male reproductive organs

32
Diseases of the Male Reproductive Organs
Cryptorchidism

• Testes do not descend into the scrotum
• Surgery necessary to correct

33

• Although the testicles of a fetus begin high in
  the abdomen, they must descend into the scrotum
  during fetal development. If they do not, the
  male may become infertile.

34
Diseases of the Male Reproductive Organs
Testicular torsion

• testis is twisted on its spermatic cord
• many causes (sex, exercise, sleep)
• symptoms are pain and swelling
• immediate surgery is required to maintain the
  testicle

35

• Testicular torsion can occur after exercise,
  sexual intercourse, and even while sleeping.

36
Diseases of the Male Reproductive Organs Priapism

• persistent, painful erection not related to
  sexual excitement
• blood is trapped in erectile tissue
• common causes are drug use and unknown
• treatment is cessation of drug use and, possibly,
  surgery

37
Diseases of the Male Reproductive Organs
Peyronies Disease

• painful curvature of the penis making penetration
  impossible
• cause is unknown
• may disappear within 2 years, or require drugs or
  surgery

38
Other Conditions that Affect the Male
Reproductive Organs

• Anabolic-androgenic steroid use
• synthetic testosterone can increase muscle mass
  and endurance
• there are also numerous physical, psychological,
  and emotional side effects, including erectile
  problems
• Inguinal hernia
• intestine goes through an abdominal opening into
  the scrotum, creating a bulge
• can be due to heavy lifting and straining
• surgery may be required
• Hydrocele fluid accrues forms a scrotal mass

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Cancer of the Male Reproductive Organs

• Testicular
• Penile
• Prostate

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Testicular Cancer

• Most common cancer in men 15-44 years
• Few early symptoms, early detection important
  testicular self-exam
• Symptoms painless mass or hardness in the
  testes pain or increase in size of the testes,
  lower back pain, gynecomastia, shortness of
  breath, urethral obstruction
• High cure rate radiation, chemotherapy, removal
  of testicle

41
Penile Cancer

• Lesions on the penis may be benign or malignant
  and are usually treatable may also be a STI
• Penile cancer is not common

42
Prostate Cancer

• Prostate glands enlarge with age and this is
  typically unproblematic, other than interfering
  with urination
• Prostate cancer is one of the most common in
  American men, typically in men over 50 years
• Risk factors age, high fat diet, race, genetics
• Symptoms pain in the lower back, pelvis, or
  upper thigh, and urinary abnormalities
• Detected through rectal exam and blood test

43
Prostate Cancer

• Treatments watchful waiting, radical
  prostatectomy, radiation, cryosurgery, drugs that
  attack cancerous cells