Reproductive system

Reproduction Reproduction is the process by which an individual produces it’s offspring. Human reproduction employs internal fertilization and depends on the integrated action of hormones, the nervous system and the reproductive system. Gonads are sex organs that produce gametes. Male gonads are testes, which produce sperm and male sex hormones. Female gonads are ovaries, which produce eggs (ova) and female sex hormones.

Importance of reproductive system: 1. To maintain own species in the world. 2. To increase the number of existence.

Male reproductive system

Male sex organ A.Primary sex organ : Testes B. Accessory sex organs: 1. Penis 2. Prostate gland 3. Seminal vesicle 4. Urethra 5. Epididymus 6. Vas deferens 7. Ejaculatory duct 8. Bulbo-urethral gland

Figure: The male reproductive system

The male reproductive system Testes/Testicles: The testes are oval organs, 4 cm long and 2.5 cm wide. They lie in the scrotum (loose pouch like sac hangs behind the penis), secured at either the end by a structure called the spermacit cord. Most man has two testes. They are responsible for making testosterone, the primary male sex hormone and for generating sperm.

Penis Penis is the male organ for sexual intercourse. It has three parts- A.the root- which attaches to the wall of the abdomen, B.the body or the shaft C.the glands- which is the cone-shaped end of the penis. It contains a number of sensitive nerve endings.

Prostate glands: The prostate gland is a walnut-sized structure that is located below the urinary bladder in front of the rectum. This gland contributes additional fluid during ejaculation. Prostate fluids also help to nourish the sperm. The urethra, which carries the ejaculate to be expelled, runs through the center of the prostate gland. Seminal vesicles: The seminal vesicles are sac-like pouches that attach to the vas deferens near the base of the bladder. The seminal vesicles produce sugar-rich fluid (fructose) that provides sperm with a source of energy and helps with sperm’s motility. The fluid of seminal vesicles makes up most of the volume of a man’s ejaculatory fluid, or the ejaculate.

Urethra: The urethra is the tube that carries urine from the bladder to outside the body. In males, it has the additional function of expelling (ejaculating) semen. Epididymis: The epididymis is a long, coiled tube that rests on the backside of each testicle. It has two main functions, transport and storage of sperm cells that are produced in the testes helps in maturation of sperm.

Vas deferens: The vas deferens is a long, muscular tube that travels from the epididymis into the pelvic cavity, to just behind the bladder. The vas deferens transports mature sperm to the urethra in the preparation for ejaculation. Ejaculatory ducts: These are formed by the fusion of the vas deferens and the seminal vesicles. The ejaculatory ducts empty into the urethra.

Bulbo-urethral glands: The bulbo-urethral glands, or Cowper’s glands, are pea-sized structures located on the sides of the urethra just below the prostate gland. These glands produce a clear, slippery fluid that empties directly into the urethra. This fluid serves to lubricate the urethra and to neutralize any acidity that may be present due to residual drops of urine in the urethra.

Spermatogenesis Spermatogenesis is the process by which the male gamates called spermatozoa (sperms) are formed from the primitive germ cells (spermatogonia) in the testes. Throughout the process of spermatogenesis the germ cells have cytoplasmic attachment with Sertoli cells. Sertoli cells supply all the necessary materials for spermatogenesis through the cytoplasmic attachment.

Sperm Sperm is the male reproductive cell, developed in testes. The total count of sperm is about 100 to150 million/ml of semen. Sterility occurs when the sperm count falls below 20 million/ml. The sperm consists of 4 parts, Head ( length: 3 to 5μ; width: up to 3μ ) Neck Body (cylindrical) Tail (long flagellum or filament)

Sperm

Semen  Seminal fluid is thick, yellowish, and alkaline.  It contains mucus, fructose, a coagulating enzyme, ascorbic acid, and prostaglandins.

Male Hormones Androgen Androgen means any steroid hormone having musculinizing effects. The androgens are, Testosterone Dihydrotestosterone Androstenedoine Source: #Testis # Adrenal cortex

Female Reproductive System Female reproductive organs, Primary sex organ: Ovaries Accessory sex organ: 1. Uterus 2. Vagina 3. Uterine tube 4. External genitalia 5. Bartholins gland

Female reproductive system

Ovaries: The ovaries are the female gonads, or glands, and they lie on the lateral walls of the pelvis. Structure: The medulla: This lies in the centre and consists of fibrous tissue, blood vessels and nerves. The cortex: This surrounds the medulla. It has a frame work of connective tissue covered by germinal epithelial cell. Function: Production of egg cells and female sex hormone.

Uterus: Uterus is otherwise known as womb. It has 3 parts, The fundus: Dome shaped structure of the uterus above the openings of the uterine tube The body: It is the main part. It is narrowest inferiorly at the internal wall of cervix where it is continuous with the cervix. The cervix (neck of uterus): This protrudes through the anterior wall of the vagina, opening into it at the external wall of cervix. Function: Protects and sustains the life of the embryo during pregnancy

Uterine tube (Fallopian tubes): It is 10 cm long extends from the sides of the uterus between the body and the fundus. It has 3 layers, Outer covering of peritoneum A middle layer of smooth muscle Inner layer of ciliated columner epithelium Function: i) Conveys the egg cells toward the uterus, the site of fertilization. ii) Conveys the developing embryo to the uterus. iii) Protects and sustains the life of the embryo during pregnancy.

External genitalia: It has three parts; labia majora, labia minora and clitories. Labia majora: Two large folds which form the boundary of the vulva. Composed of skin, fibrous tissue and fat contains large numbers of sebaceous glands. Function: Enclose and protect other external reproductive organs Labia minora: Two smaller folds of skin between the labia majora, containing numerous sebaceous glands. Function: Form the margins of the vestibule Protects openings of the vagina and urethra

Vagina: Fibromuscular tube lined with squamous epithelium, connecting the external and internal organs of reproduction. It has 3 layers~ Outer covering of areolar tissue Middle layer of smooth muscle and Inner layer of stratified squamous epithelium that forms ridges or rogue. Function: Receive the erect penis during sexual intercourse.

Hormones of Female Reproductive System The ovaries of sexually mature females secrete two major hormones, Estrogen and Progesterone Functions of estrogen: Growth and maturation of different reproductive organs in female Development of secondary sexual character Participates in pregnancy if it occurs. Functions of progesterone: It has many effects in the body but the reproductive functions include roles in menstrual cycle and pregnancy.

Hormones Involved in the Female Reproductive Cycle Gonadotropin Releasing Hormone (GnRH) Follicle Stimulating Hormone (FSH) Luteinizing Hormone (LH) Estrogen Progesterone