The Reproductive System

1. The Reproductive System

2. The Pelvis and Perineum • Pelvic wall is formed by a. Pelvic girdle b. Sacrum c. Os coxae (ilium, ischium, and pubis)

3. The three os coxae bones (innominate bones) come together to form the ACETABULUM (hip socket). • The PELVIC BRIM is a line that separates the FALSE PELVIS (superior to the brim) and the TRUE PELVIS (inferior to the brim).

4. The pelvic inlet is also formed by the PROMONTORY of the sacrum and a line drawn to the pubic symphysis. • The PELVIC OUTLET is formed by a line from the inferior edge of the pubic symphysis to the tip of the coccyx and the plane extends laterally to the two ISCHIAL TUBEROSITIES.

5. The pelvic inlet in females is wider than deep. • The male pelvic inlet is heart shaped. • The outlet of the female is round while on the male it is deeper than it is wide. • In the female, the wide outlet leads to a wide PUBIC ARCH.

6. Gender Differences in the Pelvis

7. There is no barrier that separates the abdominal and pelvic cavities. Therefore, intestines can drop into the pelvis and the bladder and uterus (females) can ascend into the abdomen. • In males: RECTOVESICULAR POUCH • In females: RECTOUTERINE POUCH

8. These pouches are sacs within the posterior portions of the pelvic cavities. Debris can accumulate in these cavities and be a source of infection. • The peritoneal fluids circulate within these pouches. • The bladder and uterus are outside the peritoneum (retroperitoneal)

9. The PELVIC DIAPHRAGM -muscular barrier across the pelvic outlet. -prevents pelvic contents from falling out. -LEVATOR ANI muscle (anterior)-raises the anus -COCCYGEUS muscle is posterior and smaller

10. The EXTERNAL SPHINCTER ANI is voluntary • The INTERNAL SPHINCTER ANI is involuntary and part of the rectum. • There is an opening in the levator ani (urogential diaphragm) for the UROGENITAL TRIANGLE and ARCH. This is where the urogenital organs pass.

14. Reproduction • A species goal is to reproduce. • 2 types: 1. ASEXUAL (without sex) a. 1 partner b. Parent and children are identical 2. SEXUAL a. 2 cells combine (fertilization) b. Children are similar but not identical to parents.

15. Sex cells (sperm and egg) are made by MEIOSIS. This form of cellular reproduction reduces the number of chromosomes by half. 23 chromosomes per egg 23 chromosomes per sperm 46 chromosomes per zygote (fertilized egg)

16. Humans are SEXUALLY DIMORPHIC. There are two distinct forms. The primary sex organs are the TESTES (male) and OVARIES (female). They produce sex cells called gametes. They are also MIXED GLANDS. In females, all meiosis is complete before birth-therefore, all the eggs that will be present are there at birth. They are dormant. In males, meiosis begins at puberty. Therefore, spermatozoa will be produced throughout the males life from puberty to death.

17. The gonads (testes and ovaries) produce hormones. They are endocrine glands. 1. Testosterone in males 2. Estrogen and Progesterone in females

18. Sexual Accessory Organs help get the gametes to where they have to go: Males: tubules, penis Females: vagina, uterus, cervix, oviducts

19. Secondary Sex Characteristics • Due to hormones. • Have nothing to do with reproduction. They include: • Facial and body hair • Voice changes • Mammary glands capable of milk production • Increased musculature • Shoulders, range of motion increase • Increase in adipose tissue (fat) in female hip and buttocks • Aggression increases • Sex drive increases

20. THE MALE • Urine and semen both travel through the same tube (urethra) • There is a cord from the inguinal ligament to the scrotum. This the SPERMATIC CORD which contains blood vessels, nerves, and vas deferens.

22. The URETERS from the kidneys lead to the caudal end of the bladder. The URETHRA passes caudally from the bladder. • A short distance down the urethra you will find the PROSTATE GLAND. Inferior to this gland is the ROOT of the penis.

23. SPERMATIC FASCIA is the covering for the spermatic cord. The spermatic cord ends in a sac that contains the testes. • The testes are oval shaped. Which contain the SEMINIFEROUS TUBULES. • Remember, the testes begin in the abdominal cavity and descend into the scrotum. • As they descend, the inguinal ligament evaginates and the spermatic fascia is formed form the aponeuroses of the inguinal ligament.

24. The peritoneum lining the fascial sac is the TUNICA VAGINALIS. • Within the spermatic cord are muscle fibers from the internal oblique muscle. This forms the CREMASTER MUSCLE. When it contracts, this muscle lifts the testicle. This is important in maintaining an adequate temperature for sperm production.

25. The scrotum is the outer skin and muscle covering the testicles. The muscle within the scrotum is the DARTOS MUSCLE. • This muscle is responsible for wrinkling the skin of the scrotum also helping in keeping a stable, cooler temperature.

26. The EPIDIDYMIS is attached to the testis. It has a head, body, and tail which empties into the vas deferens. • The testicle is covered by a “visceral” layer called the TUNICA ALBUGINEA.

27. Internally, the testis has a network of SEMINIFEROUS TUBULES which combine to form a layer of ducts called the RETE TESTIS. The VAS EFFERENS are another layer that leads to the epididymis. • Sperm is stored in the epididymis

30. Whole Fetal TestisThe human (5 1/2 month fetal) testis is covered by a dense fibrous tunica albuginea which contain developing blood vessels.

31. 1 – seminiferous tubules 2 – sperm 3 – spermatid 4 – spermatocyte 2 5 – spermatocyte 1

32. Sperm finishes its development in the epididymis-gains a tail and its shape is streamlined. • The head of the sperm contain enzymes that dissolve the COROLLA of the ovum. • The vas deferens connects to the SEMINAL VESSICLES via the SEMINAL DUCT. After this the vas deferens is called the EJACULATORY DUCT.

34. Sperm Identify the head, mid-piece, and tail. Notice the light staining acrosome at the tip of the head

39. Penis This cross section of the penis shows the erectile tissues of both the corpus spongiosum (lower right) and one of the corpora cavernosa (upper left).

43. The urethra pass through the prostate gland and has many fenestrations. The prostate dumps materials into the semen through these holes. The ejaculatory duct empties into the PROSTATIC URETHRA. • The prostatic urethra is connected to the BULBOURETHRAL GLANDS or COWPER”S GLAND. Here lubricants are added to the semen. After this gland, the semen enters the PENILE URETHRA from which it leaves the body. • The root of the penis is anchored to the body. The root has a bulb in the enter and two wings (crura) on either side.

44. The penis itself is made of three cylinders of spongy tissue. 1. 2 corpus cavernosum 2. 1 corpus spongisoum The spongiosum contains the penile urethra. The spongy tissue in all three cylinders contain spaces which become engorged with blood during sexual arousal – erection.

45. These three cylinders compose the BODY of the penis. • The body ends in the GLANS. • Erection is an PARASYMPATHETIC response. • Ejaculation is a SYMPATHETIC response.

46. For Your Information….. • There are collagen fibers that run on the outside surface of the erectile tissue. This collagen lies at right angles to the circular fibers in the shaft. This design is to prevent the erect penis from buckling or kinking during intercourse.

47. Identify the Following: Penis bladder Testicle rectum Epididymis sacrum Vas deferens prostate gland Ureter bulbourethral gland Urethra seminal vessicle Corpus spongiosum seminal duct Corpus cavernosum crus of penis Glans Scrotum Pubic symphysis

48. THE FEMALE • In the female cat, cut through the pubic symphysis. You will see a VESTIBULE. The urethra empties into the vagina through the UROGENITAL SINUS. • In humans, the urethra empties into the vestibule with the vagina. • At the end of the vagina, you will see the opening into the uterus. This is the CERVIX.

49. Vaginal mucosa Endocervical opening uterus