reproduction Human Reproductive System The reproductive system is

reproduction

Human Reproductive System The reproductive system is the system that allows for the continuation of the human species This system is different in males and females

Human Reproductive System The role of the male’s reproductive system is to manufacture sperm and then to deliver them to the female’s reproductive tract where fertilization may occur

Human Reproductive System The role of the female’s reproductive system is basically the same except that it goes further if the sperm meets an egg. If fertilization occurs the female reproductive system is designed to nurture and care for the cell that will soon grow into a baby

Human Reproductive System n n The sperm is produced in the male testis and then travels through a series of ducts to reach the body exterior The eggs are produced in the ovary of a female. When a egg is to be expelled or ovulated a “blister forms on the exterior of the ovary. When the “blister” bursts the egg may be collected by the ends of the fallopian tubes and travels through the fallopian tubes where it can be fertilized by a single sperm

Human Reproductive System n n n If an egg is fertilized it travels down into the uterus where it embeds in the wall of the uterus. There it divides rapidly and the cells begin to specialize into the different organs of a pregnancy. Some of the cells form the amniotic sac while some form the placenta and the umbilical cord. Only a small number of these cells will eventually form the fetus

male reproductive system The scrotum and penis are the male genitalia. The male gonads, called testis, are tightly coiled tubes surrounded by tissue. Sperms develop in these tubes. The male gonads are located outside of the body since sperm productions can only occur at about two degrees Celsius lower than normal body temperature. After the sperm are produced they mature and are stored in the epididymis.

male reproductive system The male reproductive system also contains three glands that add secretions to the semen. seminal vesicles prostate gland Cowper's glands

seminal vesicles Sixty percent of semen is secreted by the seminal vesicles. They lie behind and below the bladder and empty directly into the ejaculatory duct. The fluid secreted is clear and thick. It contains mucus, amino acids, and fructose. The fructose provides energy for the sperm.

prostate gland Cowper's glands n n The prostate gland surrounds the beginning of the urethra in which it secretes its products. Prostatic fluid is milky, thin, and alkaline in order to balance the acidity of any urine remaining in the urethra and the acidity of vaginal fluids Cowper's glands lie along the urethra below the prostate. Although their specific function is still unknown, they do secrete a viscous fluid before ejaculation

Testoterone n the male reproductive hormone made by the testes which causes the changes of puberty. n This hormone causes secondary sex characteristics, production of sperm. Click here

SEMEN: n a combination of fluid that is produced in the seminal vesicles, prostate gland, and Cowper's gland. This fluid nourishes and helps sperm move through the urethra. Click here

female Reproductive System Ovaries, the female gonads, are located below the digestive system in the abdominal cavity. Inside each ovary are many follicles which consist of a single egg cell and one or more layers of follicle cells. Follicle cells protect and nourish the egg cells. A woman is born with about 400, 000 follicles and cannot produce more.

female Reproductive System Ovulation is the process in which an egg is expelled from a follicle. The egg is expelled directly into the abdominal cavity and is picked up by the fallopian tubes. Inside the fallopian tubes are cilia which sweep the egg toward the uterus. At the neck of the uterus is the cervix followed by the vagina which has very thin walls, much thinner than those of the uterus.

female hormones n n Estrogen is responsible for the secondary sex characteristics. Progesterone builds up the lining of the uterus called the endometrium in preparation for the fertilized ovum n n Click here

fertilization n n Should sperm reach the egg, they cannot immediately fertilize it. As time must pass for their membranes to become capacitated, or weakened. This is facilitated by the cervical mucus, and in the following 6 -8 hours the sperm are gradually capacitated. After capacitation has occurred, the acrosomal reaction follows. This reaction releases enzymes in the area surrounding the egg therefore weakening the intracellural cement that surrounds the egg. Once weakened a single sperm is allowed to penetrate the egg and fertilize it.

fertilization Before fertilization can occur, the sperm must reach the egg. Each egg is only viable for 12 to 48 hours and some sperm can survive for as long as 72 hours, but most can only retain their fertilizing power for 12 to 48 hours. Therefore in order to produce offspring, sex must occur no more than 72 hours before ovulation or no later than 24 hours after.

fertilization n The moment of ejaculation, millions of sperm are released into the female’s reproductive tract. Many are able to swim up through the vagina towards the cervix. Many are killed by the acidity of the vaginal fluids. Here thousands of sperm are killed by phagocytes which recognize them as “non-self. ” Of the millions of sperm that are ejaculated, only a few thousand are able to reach the egg.