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Human Reproductive System

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Presentation on theme: "Human Reproductive System"— Presentation transcript:

1 Human Reproductive System

2 Learning Targets I can describe three functions of the male reproductive system. I can describe three functions of the female reproductive system. I can define the parts of the male and female reproductive system and label the diagrams correctly. I can define pregnancy related terms and male and female secondary sex characteristics. I can understand the menstrual cycle and how (and when) a female may become pregnant.

3 Male Reproductive System
Side View Urinary bladder Vas deferens Urethra Penis Epididymis Seminal vesicle Testis Prostate gland Bulbourethral gland Scrotum

4 Male Reproductive System
Front View Urinary bladder Vas deferens Seminal vesicle Urethra Prostate gland Bulbourethral gland Penis Epididymis Testis

5 Structure and Function
In males, the reproductive cells are called sperm. The functions of the male reproductive system are to produce sex hormones to produce and store sperm to deliver sperm to the female reproductive system There, a sperm cell may join with an egg, in a process called fertilization.

6 Male Reproductive System
Testes: Location where sperm are produced 2. Scrotum: Skin-covered sac that holds the testicles Epididymis: holding area for sperm to mature 4. Vas Deferens: Muscular tubes connecting the left and right epididymis to the ejaculatory ducts in order to move sperm 5. Seminal Vesicle: Glands that produce a white sticky fluid called seminal fluid. When mixed with sperm, called semen Prostate Gland: The main function is to secrete and store clear fluid that is part of semen

7 Male Reproductive System cont.
7. Cowper’s Gland: Glands that secrete a clear fluid known as pre-ejaculate 8. Urethra: Carries urine from the bladder and also carries semen during ejaculation Penis: External male sex organ The sex hormone testosterone affects the production of sperm and signals certain physical changes at puberty. The ejection of semen from the penis is called ejaculation. Several million sperm cells are released during one ejaculation. Ejaculation can occur when the penis is in an erect state.

8 Female Reproductive System
Side View Fallopian tube Ovary Uterus Urinary bladder Cervix Urethra Vagina

9 Female Reproductive System
Fallopian tube Front View Ovary Uterus Cervix Vagina

10 Structure and Function
The reproductive cells in females are called eggs or ova (singular, ovum). The functions of the female reproductive system are to produce sex hormones to produce eggs to provide a nourishing environment in which a fertilized egg can develop into a baby

11 Female Reproductive System
1. Ovary: The two main functions of the ovaries are to secrete hormones and release eggs 2. Fallopian Tube/Oviduct: Tubes leading from the ovary to the uterus. Carry the ovum (egg) from the ovary to the uterus Uterus: The main function of the uterus is to accept a fertilized egg which becomes implanted into the endometrium 4. Cervix: The lower, narrow portion of the uterus, where it joins with the top end of the vagina 5. Vagina: The internal muscular tube that connects the vulva on the outside to the cervix of the uterus on the inside 6. Labia Majora/Vulva: The female external sexual organ, including folds of skin and mucous membranes that cover and protect the opening to the female reproductive system

12 Sexual Development The gonads, testes and ovaries, are endocrine glands that secrete sex hormones. Testosterone in males and estrogen in females. The primary function of the gonads is not to produce hormones, but to produce and store gametes-sperm and eggs. Neither testes or ovaries are capable of producing active reproductive cells (gametes) until puberty. The onset of puberty varies among individuals. It may occur anytime from age 9 to 15.

13 Ovaries The female reproductive glands release sex hormones that regulate egg maturation and control changes in a female’s body at puberty. Testes The male reproductive glands release a sex hormone that regulates sperm production and control changes in a male’s body at puberty.

14 Male Reproductive System
The scrotum contains a muscle that acts as a thermostat. If body temperature rises, the muscles of the scrotum relax, lowering the testes away from the body. If the body temperature drops, the muscles contract, pulling the testes closer to the body. Sperm is the smallest cell in the human body Sperm will be produced for the rest of a male’s life Sperm production will slow with age A constant temperature of 95° is necessary for production of sperm

15 Male Reproductive System cont.
It takes sperm about 4-6 weeks to mature Sperm live about hours once they mature and are absorbed back into the body if not ejaculated A tiny valve at the bottom of the bladder closes, making it impossible for sperm and urine to pass at the same time Testosterone produces a number of secondary sex characteristics that appear in males at puberty-voice deepens, facial hair, and body hair Passageway the Sperm travels: Testicles→ Epididymis→ Vas Deferens→ Seminal Vesicle→ Prostate Gland→ Cowpers Gland→ Urethra

16 The Pathway of Sperm Seminal vesicles add a fluid that provides a source of energy for the active sperm. The bulbourethral glands add a lubricating fluid that aids the passage of sperm through the urethra. Sperm travel through the vas deferens to the seminal vesicles. The prostate gland adds a fluid that protects the sperm. Sperm are produced in the testes. They mature and are stored in the epididymis. Seminal vesicle Vas deferens Prostate gland Urethra Bulbourethral gland Penis Epididymis Testis

17 Female Reproductive System
Ovum (egg) is the largest cell in the body The ovaries usually produce only one egg or ovum per month and will usually alternate from one ovary one month to the other ovary the following month. However, each ovary may produce an ovum or several ova can be released from one ovary. If 2 ova are later fertilized by sperm, fraternal twins will result. Fertilization only occurs in the Fallopian Tubes

18 Female Reproductive System cont.
At the instant of fertilization a membrane grows around the ovum to prevent any other sperm from penetrating it. The fertilized ovum, or zygote, continues moving through the Fallopian Tubes to the Uterus where it attaches to the uterine wall and begins to grow and develop. The ovaries begin to produce estrogen which in turn produce secondary sex characteristics-enlargement of breast and reproductive organs, widening of the hips, and growth of body hair. Passageway the Egg travels: Ovaries→ Fallopian Tubes→ Uterus→ Endometrium


20 The Menstrual Cycle Women usually produce only one mature egg cell each month during a process called the menstrual cycle (MEN stroo ul). During the menstrual cycle, an ovary releases a mature egg. The egg travels to the uterus. If the egg is not fertilized, the uterine lining is shed and a new cycle begins.

21 Factors Affecting the Menstrual Cycle
On average, a woman’s menstrual cycle lasts 28 days. Factors such as diet, stress, exercise, and weight gain or loss also affect the menstrual cycle. The menstrual cycle may be irregular at times, especially during puberty. During menopause, the ovaries slow down their hormone production and no longer release mature eggs.

22 Stages of the Menstrual Cycle
During the first half of the cycle, an egg matures inside one of the ovaries. At about the middle of the cycle ovulation occurs. If the egg has not been fertilized by the time it reaches the uterus, the uterine lining breaks down. The blood and tissue of the thickened lining pass out of the body through the vagina in a process called menstruation.

23 The Menstrual Cycle Days 1–4 The uterine lining is shed during menstruation. Days 5–13 An egg matures in one of the ovaries, and the uterine lining starts to thicken. Egg Maturing Egg Days 14–15 The ovary releases the mature egg during ovulation. Days 16–22 The egg travels through the fallopian tube to the uterus, and the uterine lining continues to thicken. Days 23–28 The unfertilized egg enters the uterus.

24 Menstrual Discomfort Cramps are caused by contractions of the uterus.
Premenstrual syndrome, or PMS, is marked by nervous tension, mood swings, headaches, bloating, and irritability. The dramatic change in hormone levels that occurs before menstruation begins may cause PMS.

25 Complications Ectopic pregnancy In very rare cases of ectopic pregnancy, the blastocyst implants in the fallopian tube or elsewhere in the abdomen, instead of in the uterus. Miscarriage The death of an embryo or fetus in the first 20 weeks of pregnancy is called a miscarriage. Preeclampsia Also called toxemia, preeclampsia (pree ih KLAMP see uh) is characterized by high blood pressure, swelling of the wrists and ankles, and high levels of protein in the urine. Gestational Diabetes Diabetes that develops in pregnant women is called gestational diabetes, and is marked by high blood sugar levels.

26 Complications at Birth
Some complications result in a surgical delivery or premature birth. Low birthweight and the birth of more than one baby also may cause complications. A stillbirth occurs when a fetus dies and is expelled from the body after the twentieth week of pregnancy.

27 Surgical Delivery Sometimes delivery through the cervix and vagina is not possible because of the position of the fetus in the uterus the narrowness of the mother’s hips illness other conditions A cesarean section (suh ZEHR ee un) is a surgical method of birth. First the doctor makes an incision in the lower abdomen into the uterus, then he or she removes the baby and placenta.

28 Review: Learning Targets
I can describe three functions of the male reproductive system. I can describe three functions of the female reproductive system. I can define the parts of the male and female reproductive system and label the diagrams correctly. I can define pregnancy related terms and male and female secondary sex characteristics. I can understand the menstrual cycle and how (and when) a female may become pregnant.

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