THE REPRODUCTIVE SYSTEM 4th partial 8th grade

The Male Reproductive System The organs of the male reproductive system are specialized for the following functions: To produce, maintain and transport sperm (the male reproductive cells) and protective fluid (semen) To discharge sperm into the female reproductive tract To produce and secrete male sex hormones The human male reproductive system (or male genital system) consists of a number of sex organs that are a part of the human reproductive process. These sex organs are located outside the body.

The main male sex organs are: the penis and the testes which produce semen and sperm. When there is sexual intercourse it fertilizes an ovum in the female body and the fertilized ovum (zygote) gradually develops into a fetus, which is later born as a child. The male reproductive anatomy includes internal and external structures.

What are the external reproductive structures What are the external reproductive structures? Most of the male reproductive system is located outside of the man’s body : the penis, the scrotum and the testicles. Penis — is the male organ for sexual intercourse. It has three parts: a.Root attached to the wall of the abdomen b.Body, or shaft c.Glans, called the head of the Penis covered with a loose layer of skin called foreskin. (This skin is sometimes removed in a procedure called circumcision.) The opening of the urethra, the tube that transports semen and urine, is at the tip of the glans penis. The penis also contains a number of sensitive nerve endings.

The body of the penis is cylindrical in shape and consists of three internal chambers. These chambers are made up of special, sponge-like erectile tissue. This tissue contains thousands of large spaces that fill with blood when the man is sexually aroused. As the penis fills with blood, it becomes rigid and erect, which allows for penetration during sexual intercourse. The skin of the penis is loose and elastic to accommodate changes in penis size during an erection.

Testicles (testes) — The testes are oval organs about the size of large olives that lie in the scrotum, secured at either end by a structure called the spermatic cord. Most men have two testes. The testes are responsible for making s, the primary male sex hormone, and for generating sperm. Within the testes are coiled masses of tubes called seminiferous tubules. These tubules are responsible for producing the sperm cells through a process called spermatogenesis.

Epididymis — The epididymis is a long, coiled tube that rests on the backside of each testicle. It functions in the transport and storage of the sperm cells that are produced in the testes. It also is the job of the epididymis to bring the sperm to maturity, since the sperm that emerge from the testes are immature and incapable of fertilization. During sexual arousal, contractions force the sperm into the vas deferens.

Vas deferens and Ejaculatory Ducts 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 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.

The urethra is the tube that carries urine from the bladder to outside of the body. In males, it has the additional function of expelling (ejaculating) semen when the man reaches orgasm. When the penis is erect during sex, the flow of urine is blocked from the urethra. Seminal vesicles are sac-like pouches that attach to the vas deferens near the base of the bladder. The seminal vesicles produce a sugar-rich fluid (fructose) that provides sperm with a source of energy and helps with the sperms’ motility (ability to move).

Prostate gland — The prostate gland is a walnut-sized structure that is located below the urinary bladder in front of the rectum. The prostate gland contributes additional fluid to the ejaculate. Prostate fluids also help to nourish the sperm.

How does the male reproductive system function How does the male reproductive system function? The entire male reproductive system is dependent on hormones, which are chemicals that stimulate or regulate the activity of cells or organs. The primary hormones involved in the functioning of the male reproductive system are follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone.

The human female reproductive system (or female genital system) Contains two main parts: the uterus, which hosts the developing fetus, produces vaginal and uterine secretions, and the ovaries, which produce the egg cells. These parts are internal. The vagina meets the external organs at the vulva, which includes the labia, clitoris and urethra. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the Fallopian tubes. At certain intervals, the ovaries release an ovum, which passes through the Fallopian tube into the uterus.

If, in this transit, it meets with sperm, the sperm penetrate and merge with the egg, fertilizing it. The fertilization usually occurs in the oviducts, but can happen in the uterus itself. The zygote then implants itself in the wall of the uterus. When developed enough to survive outside the womb, the cervix dilates and contractions of the uterus propel the fetus through the birth canal, which is the vagina.

Uterus The uterus or womb is the major female reproductive organ of humans. The uterus provides mechanical protection, nutritional support, and waste removal for the developing embryo (weeks 1 to 8) and fetus (from week 9 until the delivery). In addition, contractions in the muscular wall of the uterus are important in pushing out the fetus at the time of birth.

The fertilized ovum becomes an embryo, develops into a fetus and gestates until childbirth. If the egg does not embed in the wall of the uterus, an anatomically female person begins menstruation and the egg is flushed away.

Oviducts The Fallopian tubes or oviducts are two tubes leading from the ovaries into the uterus. On maturity of an ovum, the follicle and the ovary’s wall rupture, allowing the ovum to escape and enter the Fallopian Tubes. There it travels toward the uterus. This trip takes hours or days. If the ovum is fertilized while in the Fallopian tubes, then it normally implants in the uterus, which signals the beginning of pregnancy.

Ovaries The ovaries are small, paired organs that are located near the lateral walls of the pelvic cavity. These organs are responsible for the production of the ova and the secretion of hormones. Ovaries are ova or eggs are produced. The process by which the ovum is released is called ovulation. After ovulation, the ovum is captured by the oviduct, after traveling down the oviduct to the uterus, occasionally being fertilized on its way by an incoming sperm, leading to pregnancy and the eventual birth of a new human being.

In the absence of fertilization, the ovum will eventually traverse the entire reproductive tract from the fallopian tube until exiting the vagina through menstruation.  

Explain the two functions of the urethra. What are the hormones involved in the male reproductive system? What male characteristics does testoterone develop? What is the male foreskin? What is the ovum? What is a zygote? What happens when the ovum comes through the Fallopian tubes and meets with sperm at the uterus’ What happens when the ovum comes through the fallopian tubes and does not meet with sperm? What does uterus provide to the embryo?  

Define the following. penis uterus ovums testoterone glans urethra testes womb epidydimis scrotum foreskin    What is the function of Vas Deferens? What is the function of Seminal Vesicles? What is the function of epididymis?