The Endocrine System & Reproduction

1. The Endocrine System & Reproduction Ch. 16

2. Questions? Completely Anonymous

3. The Endocrine System • Hormones and the Endocrine System • The endocrine system produces chemicals that control many of the body’s daily activities. • Endocrine glands release chemicals directly into the bloodstream • Hormones • Turn on, turn off, speed up, slow down activities of different organs and tissues • Hormone Production • Nerve impulses from the brain • Brain interprets signals, and sends a response in the form of a hormone • Adrenaline! • Hormone Action • Adrenaline lasts until blood returns to a normal level • Target Cells • Muscle cells for adrenaline

4. The Endocrine System • Functions of Endocrine Glands • Hypothalamus • Center of your head • Controls hunger, sleep and other body processes • Major role in homeostasis • Pituitary Gland • Size of a pea • Regulates growth, blood pressure, & water balance

5. The Endocrine System • Negative Feedback • Example: thermostat • When the amount of a particular hormone in the blood reaches a certain level, the endocrine system sends signals that stop the release of that hormone

6. The Male & Female Reproductive Systems

7. Sexual Reproduction Sperm is the male sex cell 23 chromosomes Egg is the female sex cell 23 chromosomes Fertilization, 46 chromosomes Zygote

8. Male Reproductive System The Testes Clusters of tiny coiled tubes, called seminiferous tubules. Immature sperm form on the walls of these tubes until it matures, gains a flagellum and then carried to the epididymis. Located in the scrotum, stays slightly below body temperature. The Path of Sperm Cells As the sperm move the mix with fluids and become semen. This fluid allows for the sperm to swim. It also contains nutrients that the sperm use for energy. Semen travels through the urethra and exits out the penis. Bladder muscles contract as to keep urine from mixing with the semen. Ejaculation, sperm exiting the penis at over 50 million sperm. 5-10 million per drop!

9. Female Reproductive System The Ovaries Produce & store eggs Hormones Ovaries also have endocrine glands that produce estrogen. This hormone causes hips to widen and breasts to develop. The Path of the Egg Cell The fallopian tubes, oviducts, are passage ways for the eggs at they travel to the uterus. The uterus, a muscular organ the size of a pear, is where a fertilized egg will attach and pregnancy begins. If the egg is not fertilized, it starts to break down and exit through the cervix and then finally the vagina or birth canal.

10. The Menstrual Cycle 400,000 undeveloped eggs are in the ovaries. However, only 500 of those eggs will leave the ovaries and reach the uterus. An egg is released once a month, called the menstrual cycle. Stages The maturing egg with its own grouping of cells is called a follicle. At the same time the uterus begins to thicken. Halfway through the cycle the follicle ruptures and the mature egg is released into the fallopian tube, called ovulation. It can now be fertilized for the next few days. If not, it fails to implant and starts to break down. The extra blood and tissue, lining of the uterus, is sloughed off and passed out through the vagina called menstruation.

11. The Menstrual Cycle Endocrine Control Hormones trigger a girl’s first menstruation. Many girls begin between the ages of 10-14, some earlier, some later. Women continue to menstruate until about age 50. Then the production of sex hormones drops and the ovaries stop releasing mature eggs.

12. Pregnancy, Development & Birth • Development Before Birth • From Zygote to Embryo • Zygote moves down fallopian tube toward the uterus • Takes about 4 days • From one to two to four and so on… • Blastula • Differentiation of the Embryo • Process by which cells change and become specialized • Development of the Fetus • From ninth week to birth, the developed human is called a fetus • 3 months • Internal organs • 6 months • heartbeat

13. Fetal Development Month By Month

23. Pregnancy, Development & Birth • Protection & Nourishment • Membranes and other structures that form during development protect and nourish the developing embryo • Amniotic Sac • Cushions and protects embryo • Placenta & Umbilical Cord • Embryos’ blood vessels and is linked to the mother via the umbilical cord • Keeping the Fetus Healthy • This barrier helps keep the embryo healthy, but some viruses can pass. • HIV, alcohol, chemicals in tobacco and other drugs.

24. Pregnancy, Development & Birth • Birth • After 40 weeks… • Labor • Strong muscular contractions cause the cervix to dilate or open • Can last from 2-20 hours! • Delivery • Pushed through the uterus, through the vagina and out the mother’s body • Umbilical cord is clamped and then cut • Afterbirth • The placenta & other membranes • Birth & the Baby • Birth creates a strain on the baby • Pressure decreases baby’s supply of oxygen • Heart rate increases • Within seconds, the baby begins breathing with a cry or cough • Multiple Births • Twins! 1 out of 30 in the U.S. • Identical and Fraternal • Single egg splits = Id. • Two sperm, two eggs = Fr

25. Pregnancy, Development & Birth • Growth & Development • Infancy • Weight can double • Walking at 10-14 months • Simple directions, play • Childhood • Starts at 2 • Bones and muscles increase in size • Skills improve, learn to read and solve problems • Adolescence • Start to think like adults • Bodies undergo physical changes • 9-15 years, puberty • Adulthood • After 30, aging begins • Eyes can lose ability to focus, hair loss and or coloring • Great wisdom!