Chapter 22 Reproductive Systems. Male Reproductive Organs. Male Reproductive Organs. Specialized to produce, maintain the male sex cells (sperm)

Transcription

1 Chapter 22 Reproductive Systems Male reproductive organs 1 Male Reproductive Organs posterior view 2 Male Reproductive Organs Specialized to produce, maintain the male sex cells (sperm) Transport these cells together with supporting fluids to the female reproductive tract Secrete male sex hormones 3 1

2 Testes Ovoid structure about 5 cm long and 3 cm in diameter Suspended by spermatic cord Contained within the cavity of the scrotum 4 Descent of the Testes During fetal development, each testis develops near a kidney and then descends through an inguinal canal and enters the scrotum completing the journey by the eighth gestational month. 5 Structure of the Testes Tunica albuginea Mediastium testes -septa -lobules Seminiferous Tubules Epididymis 6 2

3 Formation of Sperm Cells 7 Spermatogenesis 8 Crossing Over mixes up genetic traits different colors represent the fact that one homologous chromosome comes from the individual s father and one from the mother 9 3

4 Crossing Over the genetic information in sperm cells and egg cells varies from cell to cell 10 Blood-testis barrier Prevents some substances from reaching the developing sperm Helps maintain favorable environment by isolating sperm from the man s immune system 11 Structure of a Sperm Cell 12 4

5 Male Internal Accessory Organs epididymus ductus deferens seminal vesicles prostate gland bulbourethral glands 13 Epididymus tightly coiled tubes connected to ducts within testis Support stored sperm promote maturation of sperm cells 14 Ductus Deferens muscular tubes about 45 cm each extends from epididymis to ejaculatory duct Ampulla-expanded part of ductus deferens near the end Passes through prostate into urethra 15 5

6 Seminal Vesicles attached to ductus deferens near base of bladder secrete alkaline fluid secrete fructose and prostaglandins contents empty into ejaculatory duct 16 Prostate Gland surrounds proximal portion of urethra ducts of gland open into urethra secretes a thin, milky, alkaline fluid secretion enhances fluid mobility composed of tubular glands in connective tissue also contains smooth muscle 17 Bulbourethral Glands inferior to the prostate gland secrete mucuslike fluid fluid released in response to sexual stimulation 18 6

7 Semen sperm cells secretions of seminal vesicles, prostate gland, and bulbourethral glands slightly alkaline prostaglandins nutrients 120 million sperm cells per milliliter 19 scrotum penis Male External Reproductive Organs 20 Scrotum pouch of skin and subcutaneous tissue dartos muscle smooth muscle in subcutaneous tissue; contracts to cause wrinkling of the scrotum medial septum divides scrotum into two chambers each chamber lines with a serous membrane each chamber houses a testis and epididymis 21 7

8 conveys urine and semen specialized to become erect for insertion into the vagina circumcision Penis 22 Penis 23 Erection, Orgasm, and Ejaculation Erection parasympathetic nerve impulses blood accumulates in erectile tissues Orgasm culmination of sexual stimulation accompanied by emission and ejaculation Ejaculation emission is the movement of semen into urethra ejaculation is the movement of semen out of the urethra largely dependent on sympathetic nerve impulses 24 8

9 Hormonal Control of Male Reproductive Functions hypothalamus controls maturation of sperm cells and development of male secondary sex characteristics negative feedback among the hypothalamus, the anterior lobe of the pituitary gland, and the testes controls the concentration of testosterone 25 Actions of Testosterone In fetus, stimulates formation of male reproductive organs and causes testes to descend increased growth of body hair sometimes decreased growth of scalp hair enlargement of larynx and thickening of vocal cord thickening of skin increased muscular growth thickening and strengthening of the bones increases rate of cellular metabolism and production of rbc s male sex drive 26 Organs of the Female Reproductive System 27 9

10 Organs of the Female Reproductive System Specialized to produce and maintain female sex cells (egg cells or oocytes) Transport sex cells to the site of fertilization Provides a favorable environment for a developing offspring Move the offspring to the outside Produce female sex hormone 28 Ovaries Solid, ovoid structures 3.5 cm long, 2 cm wide and 1 cm thick Held in place by several ligaments Broad ligament-largest Also attahed to uterus and uterine tube Suspensory ligament-upper end Ovarian ligament-attaches ovaries to uters 29 Ovary Structure Medulla-outer part Cotex-inner part Ovarian follicles Tunica albuginea 30 10

11 Primordial Follicles Start meiosis before birth then stop until puberty 31 Oogenesis the process of egg cell formation 32 Follicle Maturation Primordial follicle Mature (Graafian) follicle 33 11

12 Follicle Maturation 34 Ovulation 35 Ovulation 36 12

13 Female Internal Accessory Organs uterine tubes uterus vagina 37 convey eggs toward the uterus Uterine Tubes 38 Uterus hollow muscular organ that receives the embryo that has been fertilized in the uterine tube 39 13

14 Uterine Wall 40 Vagina fibromuscular tube that conveys uterine secretions, receives the penis during intercourse, and provides an open channel for offspring hymen 41 Female External Reproductive Organs labia majora labia minora clitoris vestibule vestibular glands 42 14

15 Labia Majora rounded folds of adipose tissue and skin enclose and protect the other external reproductive parts ends form a rounded elevation over the symphysis pubis 43 Labia Minora flattened, longitudinal folds between the labia majora well supplied with blood vessels 44 Clitoris small projection at the anterior end of the vulva analogous to the male penis composed of two columns of erectile tissue root is attached to the sides of the pubic arch 45 15

16 Vestibule space between the labia minora that encloses the vaginal and urethral openings vestibular glands secrete mucus into the vestibule during sexual stimulation 46 Hormonal Control of Female Reproductive Functions estrogens inhibit LH and FSH during most of the reproductive cycle 47 Effects of Estrogens Stimulates enlargement of accessory organs Stimulates the endometrium to thicken Development and maintenance of female sexual characteristics development of breasts and ductile system of the mammary glands increased adipose tissue in breasts, thighs, and buttocks increases vascularization of skin 48 16

17 Female Reproductive Cycle 49 Female Reproductive Cycle 50 Menopause usually occurs in late 40s or early 50s reproductive cycles stop ovaries no longer produce as much estrogens and progesterone some female secondary sex characteristics may disappear may produce hot flashes and fatigue May lead to osteoporosis May cause migranes, backaches 51 17

18 Mammary Glands specialized to secrete milk following pregnancy composed of lobes lobes contain alveolar glands drained by alveolar ducts which drain into alveolar ducts which drain into lactiferous ducts that leads to the nipple estrogens stimulate breast development in females 52 Sexually Transmitted Diseases silent infections most are bacterial and can be cured herpes, warts, and AIDS are viral and cannot be cured many cause infertility AIDS causes death symptoms of STDs include burning sensation during urination pain in lower abdomen fever or swollen glands discharge from vagina or penis pain, itch, or inflammation in genital or anal area sores, blisters, bumps or rashes itchy runny eyes 53 Clinical Application Prostate Enlargement benign prostatic hypertrophy occurs in most men over 50 BPH causes frequent urination risk factors include a fatty diet, having had a vasectomy, exposure to certain environmental factors, and inheriting a a particular gene that also causes breast cancer treatments include surgical removal, drugs, insertion of balloon into urethra, freezing of tumor, or insertion of a stent between lobes of prostate to relieve pressure on urethra 54 18

19 Male infertility Prostate cancer Testicular cancer Female infertility Cervical cancer Breast cancer Clinical Application 55 19