Reproductive System

Reproductive hormones Testosterone from testes sperm production & sex characteristics Estrogen from ovaries egg production, preparing uterus for fertilized egg & sex characteristics

Male reproductive system Sperm production over 100 million produced per day! ~2.5 million released per drop!

seminiferous tubule sperm spermatocytes

Male reproductive system Testes & epididymis sperm production & maturation Glands seminal vesicles, prostate, bulbourethal (Cooper’s Gland) produce white seminal fluid-nutrient-rich

Male reproductive system Testicles produces sperm & hormones Scrotum sac that holds testicles outside of body- maintains lower temperature Epididymis where sperm mature- 18 hrs Vas Deferens tubes for sperm to travel from testes to penis Prostate, seminal vesicles, Cowper’s (bulbourethal) glands nutrient rich fluid to feed & protect sperm

Testis and Spermatogenesis

Spermatozoa Head contains nucleus- contains enzymes that help the sperm enter the egg. body and tail allow movement Mitochondria- provides ATP for movement

Female reproductive system

Female reproductive system Ovaries- have 2 produces eggs & hormones- estrogen & progesterone Uterus Site for fetal development, nurtures fetus; lining builds up each month- menstruation- shedding of the lining of the uterus. Fallopian tubes- 2 tubes for eggs to travel from ovaries to uterus Fertilization occurs in the fallopian tubes Cervix (separates vagina from uterus) opening to uterus, dilates 10 cm for birthing baby Vagina birth canal for birthing baby

Female reproductive system

Egg maturation in ovary releases progesterone maintains uterus lining produces estrogen

Menstrual cycle Controlled by interaction of 4 hormones FSH & LH estrogen progesterone FSH ovulation = egg release egg development corpus luteum estrogen progesterone lining of uterus days 7 14 21 28

Female reproductive cycle Feedback Female reproductive cycle egg matures & is released (ovulation) builds up uterus lining estrogen ovary corpus luteum progesterone FSH & LH fertilized egg (zygote) maintains uterus lining HCG yes pituitary gland corpus luteum pregnancy GnRH no progesterone corpus luteum breaks down progesterone drops menstruation maintains uterus lining hypothalamus

Female hormones FSH & LH Estrogen Progesterone stimulates egg development & hormone release peak release = release of egg (ovulation) Estrogen stimulates growth of lining of uterus decreasing levels causes menstruation Progesterone stimulates blood supply to lining of uterus

Fertilization

Fertilization- process where sperm enters and fertilizes egg (ovum)- resulting in the formation of a zygote

Sex Determination in Mammals

Twins Identical Twins- ONE fertilization Zygote splits into two with each being identical to one another

Fraternal Twins- TWO fertilizations Two different zygotes (different egg and sperm)

Siamese Twins- identical twins whose bodies fail to fully separate- and stay joined together

Placenta & umbilical cord Allows for nutrients and gases to be exchanged between mom and child Food & gases diffuse across blood vessels

Human fetal development 4 weeks 7 weeks

Human fetal development 10 weeks

Human fetal development 12 weeks 20 weeks

Human fetal development The fetus just spends much of the 2nd & 3rd trimesters just growing …and doing various flip-turns & kicks inside amniotic fluid Week 20

Human fetal development 24 weeks (6 months; 2nd trimester) fetus is covered with fine, downy hair called lanugo. Its skin is protected by a waxy material called vernix

Human fetal development 30 weeks (7.5 months) umbilical cord

Getting crowded in there!! 32 weeks (8 months) The fetus sleeps 90-95% of the day & sometimes experiences REM sleep, an indication of dreaming

positive feedback Birth

Birth (36 weeks) Intestine Placenta Umbilical cord Wall of uterus Bladder Cervix Vagina

And you think 9 months of Biology is hard! The end of the journey! And you think 9 months of Biology is hard!

Harmful Environmental Factors Embryo’s inherited genes can cause diseases Mutations- changes in DNA (DNA makes up chromosomes) Mother’s exposure to harmful environmental factors such as DRUGS, POOR DIET, ALCOHOL, TOBACCO can cause developmental problems and learning disabilities Sexually Transmitted Diseases (STDs)- diseases passed on from person to person through sexual contact AIDS, Chlamydia, Syphilis

Let’s Practice! 1. Which statement about the gametes represented in the diagram below is correct? They are produced by females. They are fertilized in an ovary. They transport genetic material. They are produced by mitosis.

2. Base your answer on your knowledge of biology and on the diagrams 2. Base your answer on your knowledge of biology and on the diagrams. Testosterone is produced by structure A structure B structure C structure D

3. Base your answer to this question on the diagram below, which represents some stages in the development of an embryo, and on your knowledge of biology. The arrow labeled X represents the process of meiosis recombination differentiation cloning

4. Base your answer on the diagram and your knowledge of biology 4. Base your answer on the diagram and your knowledge of biology. Gamete cells are produced within structures A and J structures E and G structures B and I structures D and H

5. The diagram represents some stages in the development of an embryo 5. The diagram represents some stages in the development of an embryo. Which stage represents a zygote? stage A stage B stage C stage D

6. The primary function of structure X is to produce energy needed for sperm to move provide food for the sperm to carry to the egg produce and store urine form gametes that may be involved in fertilization

7. Although all the body cells in an animal contain the same hereditary information, they do not all look and function the same way.  The cause of this difference is that during differentiation embryonic cells use different portions of their genetic information the number of genes increases as embryonic cells move to new locations embryonic cells delete portions of the chromosomes genes in embryonic cells mutate rapidly

8. Which hormone has the lowest concentration on which day? hormone A on day 4 hormone B on day 2 hormone C on day 12 hormone D on day 20

9. During which five-week period did the fetal mass increase at the greatest rate? weeks 10–15 weeks 15–20 weeks 25–30 weeks 30–35

10. Human egg cells are most similar to human sperm cells in their degree of motility amount of stored food chromosome number shape and size

11. The process of meiosis formed cell 1, only cells 1 and 2 cell 3, only cells 2 and 3

12. Heavy cigarette smoking and the use of alcohol throughout pregnancy usually increase the likelihood of the birth of twins the birth of a male baby a baby being born with a viral infection a baby being born with medical problems

13. A large number of sperm cells are produced by males every day 13. A large number of sperm cells are produced by males every day. This large number of sperm cells increases the chance that at least one sperm cell will be reached when the eggs swim toward the sperm cells in the ovary several sperm cells will unite with an egg so the fertilized egg will develop properly some of the sperm cells will survive to reach the egg enough sperm cells will be present to transport the egg from where it is produced to where it develops into a fetus

14. In 1993, there were only 30 panthers in Florida 14. In 1993, there were only 30 panthers in Florida. They were all closely related and many had reproductive problems. To avoid extinction and restore health to the population, biologists introduced 8 female panthers from Texas. Today, there are more than 80 panthers in Florida and most individuals have healthy reproductive systems. The success of this program was most likely due to the fact that the introduced females produced more reproductive cells than the male panthers in Texas solved the reproductive problems of the species by asexual methods increased the genetic variability of the panther population in Florida mated only with panthers from Texas

15. Exposure to radiation or certain chemicals could alter the genetic information in the gametes that form in structure A B C D

16. Which event would most probably result in the production of fraternal twins? One egg is fertilized by two sperm cells. Two egg cells are fertilized by one sperm cell. Two egg cells are each fertilized by separate sperm cells. Two eggs develop without fertilization.

17. Compared to human cells resulting from mitotic cell division, human cells resulting from meiotic cell division would have twice as many chromosomes the same number of chromosomes one-half the number of chromosomes one-quarter as many chromosomes

18. Which phrase best describes a process represented in the diagram below? a zygote dividing by mitosis a zygote dividing by meiosis a gamete dividing by mitosis a gamete dividing by meiosis

19. A cell with a diploid chromosome number of 12 divided two times, producing four cells with six chromosomes each. The process that produced these four cells was most likely internal fertilization external fertilization mitotic cell division meiotic cell division

20. Which structure is correctly paired with its function? A - releases estrogen and progesterone B - produces and releases the egg C - provides the usual site for fertilization D - nourishes a developing embryo