THE (Highly Dreaded) REPRODUCTIVE SYSTEM Hey, Someone's gotto teach it. Let’s get this chapter over with STAT.

First, let’s look at how the Endocrine and Reproductive system work together. Most systems of the human body such as digestive, nervous, etc are quite similar in both male and female. However, when it comes to the reproductive system, it is very different for men and women. Males and females have structures specialized for their roles in reproduction. Hormones are a key to how human reproduction system functions. Sex hormones are necessary for the development of sexual characteristics, such as breast development in females, and facial hair growth in males. Hormones from the pituitary gland also begin the production of eggs in females and sperm in males. Eggs and sperms transfer hereditary information from one generation to the next through the process of fertilization and pass it on to their respective offspring.

Hormones and the Reproductive System The pituitary gland is located at the base of the brain. It releases female sex hormones that stimulate the production of eggs in the ovaries. It also releases male sex hormones that stimulates the production of sperm in the testes.

MALE REPRODUCTIVE SYSTEM

MALE REPRODUCTIVE SYSTEM The male reproductive System Is made up of both, internal, and external organs. The external organ of the male reproductive system are the penis and scrotum. The scrotum is a sac that contains two organs called the testes. The male sex organ is the testes and the sex cell is the sperm. As males mature, the pituitary gland sends hormonal signals to the testes to begin the production sperm. Testosterone is the male hormone and is responsible for the production of sperm.

SPERMS Sperms have a head and a tail. The head contains hereditary information, and the tail/ flagella is used to move the sperm by whipping back and forth. Because the scrotum is located outside the body cavity, the testes where the sperm are produced are kept at a lower temperature than the rest of the body. Sperm are produced in greater numbers are lower temperature. Based on this information, can you determine on fertility issue in men?

THE FEMALE REPRODUCTIVE SYSTEM

FEMALE REPRODUCTIVE SYSTEM Unlike the male reproductive organ, the female reproductive organ is completely internal. The ovaries are the female sex organ and they are located in the lower part of the body cavity or abdomen. The sex organ of the female reproductive system is the ovaries. The sex cell would be the egg or ovum. Both of the ovaries are approximately the same size and the shape of an almond. As the female matures, the pituitary gland sends hormonal signal to the ovary which stimulates the production and release of an egg.

The EGG (Ovum) When a female is born, she already has all of the cells in her ovaries that will develop into eggs. At puberty, eggs start to develop in the ovaries because of specific hormones. About once per month an egg is released. Eggs are typically released from alternating ovaries. Each month, hormones are released and sent to the target organ, the ovaries. This stimulates the ovaries to release an egg. This rocess is called ovulation.

FERTILZATION. After the egg is released from the ovaries, it goes into the oviduct. If there is sperm in the oviduct, it can fertilize the egg creating a zygote. If not, the egg is not fertilized, and this leads to menstruation. SUMMARY: When egg is released, if a sperm fertilizes it Pregnancy When egg is released, if a sperm DOESN’T fertilize it Period

THE MENSTRUAL CYCLE: (Awkward!) Please read the following article and write a summary in your notebooks. (Due Friday November 14th, 2017). https://www.womenshealth.gov/pregnancy/menstrual-cycle Women are born with approximately 2 million precursor cells that have the potential to develop into an egg. Then, when the pituitary gland sends hormones to the ovaries, it tells the ovaries to start making and releasing an egg for that month. Typically, one egg is released per month. However, there are cases in which more than one egg can be released. When an egg is released, one of two things happen: A. The egg can be fertilized leading to a pregnancy OR B. The egg is not fertilized, resulting in a period.

The Menstrual Cycle Hormones control the entire menstrual cycle. The pituitary gland releases hormones that controls a woman’s menstrual cycle. Hormones from the pituitary gland signals the ovaries to begin maturation of the egg. Hormones then signal the egg to be released from the ovaries and into the fallopian tubes or oviduct. The process of releasing an egg from the ovary is known as OVULATION.

The Menstrual Cycle: After the egg is released: The egg is released from the ovary and into the fallopian tube/oviduct. (Use the image to follow along please). If there happens to be a sperm in the oviduct, it can fertilized the released egg. This leads to the formation of a diploid cell called the zygote. The zygote will then continue moving down the oviduct towards the uterus where it will stick/ attach/ implant itself onto the uterine lining (i.e. a thick layer of blood). The uterus is a muscular organ that has a thick lining of blood that is meant to nourish the zygote and help it develop into a baby. The uterus houses the baby for 9 months.

The Menstrual Cycle: After the egg is released: Now, what happens if there is no sperm in the fallopian tube/oviduct? What happens then? Well, the egg is released from the ovary and into the fallopian tube/oviduct. The egg continues moving down the oviduct and towards the uterus. On its way down, it does NOT meet any sperm. So, it remains an unfertilized egg. It continues moving along the oviduct and towards the uterus. Because it is unfertilized, it cannot implant itself onto the uterine lining. Also, since it is unfertilized, the uterine lining is no longer needed because there is no zygote. Therefore the thick layer of blood isn’t needed to help nourish the zygote into a baby. As a result, the uterine lining is shed or released from the body in the form of a period.

RECAP The function of the reproductive system is to produce sex cells which will then fuse and form a zygote. The zygote then goes on to become a baby. Once the first sperm touches the egg, a chemical reaction occurs that prevents any other sperm from penetrating the egg. This joining or fusion of the nuclei of a sperm and egg creates a fertilized, diploid cell called the zygote. The zygote then undergoes many mitotic divisions, creating many cells that ultimately forms a baby. The uterus is a hollow, pear-shaped, muscular organ. It’s the baby’s home for the next 38-40 weeks.

MOVING ON…

HUMAN LIFE STAGES Fertilization Zygote Embryo Fetus Infancy Childhood Adolescence Adulthood Older Adulthood ( aka. Senescence).

DEVELOPMENT BEFORE BIRTH: After fertilization, the zygote moves along the oviduct/ fallopian tubes towards the uterus. After about 7 days, the zygote attaches to the wall of the uterus. If the attachment is successful, the zygote will develop into a baby in approximately nine months. This period of development from fertilized egg to birth is known as a pregnancy. After the zygote attaches to the wall of the uterus it is now referred to as the embryo. After the first two months of the pregnancy, the developing embryo is called a fetus.

Birthing Process There are 2 way to deliver a baby: 1. Delivery via the birth canal 2. Cesarean Section: the doctor has to cut through the abdominal wall to deliver the baby.

AFTER BIRTH When the baby is born, it is attached to the umbilical cord. The function of the umbilical cord is to pass nutrients and oxygen from mom to the baby and to remove the waste products from the baby. The person assisting with the birthing process clamps the umbilical cord in two place and cut in between. The baby does not feel any pain from this procedure. The scar that forms from where the cord was attached is called the navel.

Other stages after birth: Infancy: Birth- 18 months Childhood: 18 months-12 years Adolescence: 12- 18 years (You might be familiar with this stage. It’s the teenage years, where your hormones are going all crazy and you get grumpy and angry for no reason at all). Adulthood: 18- death.

MULTIPLE BIRTHS

Fraternal Twins (Dizygotic twins) can be: 2 boys 2 girls 1 boy and 1 girl Fraternal twins occur when 2 sperms fertilize 2 eggs resulting in 2 non-identical zygotes.

Identical Twins (Monozygotic twins) can be: 2 boys 2 girls Identical twins result from the fusion of 1 egg and 1 sperm. A single zygote is then formed. If this zygote splits before it is implanted in the uterus, the result is 2 identical zygotes which results in identical twins. What if the zygote started splitting before it is implanted in the uterus, but mid-way through splitting it is implanted in the uterus? The result is conjoined twins.

CONJOINED TWINS #SiameseTwins

Well teaching the reproductive system wasn’t awkward at all Well teaching the reproductive system wasn’t awkward at all. (Said no Science teacher ever!) Let’s pretend like it never happened. Lol.