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“Let’s Talk About Sex, Baby” The Complete Guide to the Human Reproductive System

Table of Contents What Is Reproduction?

Page 3 ​

Meiosis- The Story of A Nucleus P ​age 8 Key Terms About Chromosomal Mutations Page 11 Part of the Male and Female Reproductive Systems ​ Page 13 Puberty ​ Page 15 The Menstrual Cycle ​ Page 18 Fertilization and Childbirth P ​age 19 Birth Control ​ Page 29

What Is Reproduction?

WHAT IS REPRODUCTION? Reproduction is the process by which new organisms are produced. Reproduction also causes genes to be passed down.

WHY IS REPRODUCTION IMPORTANT? Reproduction is important because it causes more organisms to be produced. This allows the population to not become extinct or endangered. In addition, reproduction allows traits to be passed down from parents to their offspring. This passing down of traits also involves mutations, which are changes in the genetic code. Some mutations have positive benefits, while others can have adverse effects. Through mutations being passed down and species changing, evolution occurs.

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WHAT THINGS REPRODUCE? All living things reproduce!

How To Identify Living Things: If something carries out these processes and fits these characteristics, then it's living!

● Movement ● Respiration (Breathing) ● Sensitivity (Responding to change) ● Growth and development ● Excretion (Releasing waste) ● Reproduction ● Nutrition (Eating) ● Made up of cells and has an organization ● Uses energy ● Homeostasis

WHAT IS ASEXUAL REPRODUCTION? Asexual reproduction is when there is only one parent involved in the process of reproduction. All the genes originate from the single parent.

TYPES OF ASEXUAL REPRODUCTION ● Binary Fission:​ This form of reproduction is commonly done by bacteria. In this process, the cell elongates, the DNA is copied, the cell wall and plasma membrane begin to divide, and eventually the parent cell splits into two daughter cells. ● Budding: ​ In this type of asexual reproduction, the bud, or offspring, is a small unit that grows on the body of the parent. As each bud becomes bigger, it procures more qualities of the parent. Eventually, it falls off and becomes an individual, or it may separate from the parent after it has completely developed and grown. An organism that reproduces through budding is a sponge. ● Mitosis:​ Mitosis is the process in which two daughter cells are formed from a parent cell, which are identical. This is commonly known as cell division. Look below to see each step of mitosis and what happens.

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THE PROCESS OF BINARY FISSION

THE PROCESS OF BUDDING

Observe each step of binary fission, along with a drawing stimulating the situation of the cell.

Observe each step of budding of the Hydra, along with pictures of the organism at each step.

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BINARY FISSION FROM AN ELECTRON MICROSCOPE This picture was taken by an electron microscope of a bacteria going through binary fission. Can you guess what stage this is by using your knowledge and other resources on this Smore?

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WHAT IS SEXUAL REPRODUCTION? Sexual reproduction is the process by which an organism is created by two different parent organisms. This means that the genetic information of the offspring is not completely identical to one parent, but is a mix of the two parents.

TYPES OF SEXUAL REPRODUCTION ● Transformation: ​ Organisms, most commonly bacteria, pick up DNA from their surroundings and attempt to use it. This causes the merging of two different sources of genetic material. ● Transduction: ​ The DNA of one bacterial cell is moved to another through a virus. After the virus is released from the host cell and goes to infect another cell, at times, viruses cut out a bit of the host cell's DNA, so as they go around, they carry bacterial DNA, which

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they pass around. In addition, when the bacteria keeps reproducing, and the virus is in a stagnant state, the viral DNA, which is a part of the host DNA, is passed around in the form of bacterial cells.

Meiosis:​ This process is vital for sexual reproduction. It makes gametes, or sex cells, such as the sperm and the egg. The sperm and egg are vital because they carry genetic information of two different organisms, and if the two cells merge to create a zygote, it can form into an embryo. An embryo is an offspring which is still developing.

Conjugation:​ A pilli (a hair that is used for sticking to things, commonly found in bacteria) has a gene that causes it to become a tube. Through the tube, the cell connects itself to another bacterial cell. Then, a copy of genetic material (copy of DNA or a copy of the genes in the plasmid) is sent to the other cell through the tube.

Fertilization:​ Fertilization is the process in which two gametes (sex cells which have only one set of chromosomes) join together, or fuse. This causes the development of a new offspring to begin.

Human Fertilization: ​ Through the process of sex, when the sperm cells of the male, enter the female in the form of semen, find an egg, and fertilizes it, a zygote is created.

The zygote will eventually, if correctly maintained, will form into an embryo, which, after an approximated time of 9 months, will be brought out of the female.

Pollination:​ Since angiosperms, or flowering plants, can't move and reproduce like humans do, they need a pollinator to help transfer the genetic material from the male parts of a plant to the female parts of another plant. Pollen carries the genetic material from the male parts, which is carried from plant to plant by a pollinator. A pollinator is usually a bird, bat, or a bee. Flowers attract the flying animals to come and find nectar.

Nectar is a liquid that is sugary that plants release. When the pollen is left on the other plant, it fertilizes the plant's ovary, and a seed begins to form.

TRANSFORMATION, TRANSDUCTION, AND CONJUGATION Image Courtesy of Boundless

MEIOSIS Image Courtesy of Encyclopedia Britannica

ONE EGG, MULTIPLE SPERM Image Courtesy of Animal­Kid

PROCESS OF POLLINATION

HUMAN FERTILIZATION

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POLLINATION BASICS Image Courtesy of Easy Science for Kids

ASEXUAL REPRODUCTION VS. SEXUAL REPRODUCTION

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MEIOSIS THE PROCESS FROM THE POINT OF VIEW OF THE NUCLEUS

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WHAT IS MEIOSIS?

Meiosis is the process in which gametes (or sex cells) are produced. The purpose of meiosis is to produce haploid gametes. (Haploid means "containing only one set of chromosomes").

OVERVIEW OF MEIOSIS

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Diploid (Cell with two sets of chromosomes) ­> Cell that has replicated its DNA (Tetraploid­ cell with four sets of chromosomes) ­> Cell splits into two diploid cells ­> The two diploid cells split into 4 cells which all have one set of chromosomes.

STEPS OF MEIOSIS IN THE POINT OF VIEW OF THE NUCLEUS Refer to the diagram of meiosis above as you follow along with this narration.

INTERPHASE It's the beginning. This cell is about to be split. I can feel it. It's going through interphase.​ The DNA is getting replicated, and now there are four sets of chromosomes in this cell. ​ As we are getting ready for meiosis, ​ our one centrosome duplicates and becomes two.​ The start of this process has me wondering: where will we end up?

PROPHASE I The ​ four chromosomes are lining up in the middle of the cell, in sets of two, which is called synapsis. ​ This makes it look like there are four sister chromatids lined up in one; this tetrad is going to go through the most intriguing concept I've ever had to understand as a nucleus: crossing over. The DNA is exchanged between the chromatids.​ When I studied about this, it's said to cause genetic variation and new combinations of traits.This is why all of the gametes that the parent cell will form are different. Controlling all of this makes me feel proud. There is

always the potential of a new individual being born, due to my commanding. Along with the crossing over, the ​ centrosomes (they're also called centrioles sometimes) move to the poles of the cell and start to make spindle fibers.

METAPHASE I Here, in this phase, it's fairly calm in the cell. The ​ tetrads are at the equator of the cell and have attached to the spindle fibers made by the centrosomes.​ But as they say, it's always quiet before the storm.

ANAPHASE I This is when it all breaks apart, literally.​ The spindle fibers begin to shorten and pull the sister chromatids (or a singular chromosomes) towards the pole.

TELOPHASE I This is perhaps the first goodbye I will be saying. It does give me great pain to see my cell split, but I know it is for the good of the body. Soon enough, this will help it reach its potential. ​ The sister chromatids reach the poles and the cell divides into two diploid cells.

PROPHASE II It's common to hear that all good and bad things come in sets of three, but for now I believe they come in sets of two, just like meiosis. Prophase II begins the second part of meiosis. ​ The chromatids move to the equator. However, there is no crossing over in this phase.

METAPHASE II Once again, the quiet before the storm settles into place. However, the cells have gotten used to it. ​ The chromatids line up, once again, at the equator and attach to the spindle fibers of the centrosomes.

ANAPHASE II The centromere breaks; the chromatids begin to move towards the poles.​ Now, there is no chromosomes. There are only chromatids.

TELOPHASE II The last meeting. The last time these chromosomes will be in a cell together. Memories are made, but these memories will be forgotten. Only I will have a faint recognition of them. For the last time, the chromatids reach the poles of the cell and the ​ last cell division occurs. Now, there are four haploid cells, meaning there are four cells that all have only one set of chromosomes.

Key Terms About Chromosomal Mutations

Haploid (1N) An organism or cell with one set of chromosomes. EX: Sex cells (Egg and Sperm) Diploid (2N) An organism or cell with two sets of chromosomes. EX: Normal human beings Tetraploid (4N) An organism or cell with four sets of chromosomes. EX: The parent cell in meiosis interphase, when the DNA replicates.

Mutation A change in the nucleotide sequence of DNA Chromosomal Mutation A mutation that produces change in the entire chromosome. It changes the number or structure of chromosomes.

Chromosomal Deletion A gene is deleted. This makes the chromosome shorter.

Chromosomal Duplication An extra copy of all or parts of a chromosome is made and attached. This makes the chromosome longer.

Chromosomal Inversion Specific parts of a chromosome are "flip flopped" or have a change in the order.

Chromosomal Translocation A gene breaks of off one chromosome and attaches to another.

Mutagen A chemical or physical agent in the environment that causes a mutation.

Karyotype A picture of chromosomes.

Normal Amount of Chromosomes 46 chromosomes (22 pairs and 2 sex chromosomes)

Parts of the Male and Female Reproductive Systems

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Male Reproductive System: ● Seminal Vesicles​ are exocrine glands that store, and produce some of the semen. ● Ejaculatory Duct​ opens and releases sperm. Then the sperm travels to the Urethra. ● The ​ Prostate​ is another exocrine gland. It produces most of the liquid fluid in semen. ● Cowper's Glands​ are exocrine glands, which add extra fluid to the semen. They add this fluid, during the ejaculation process. This now thick fluid acts as a lubricant. With a less watery environment, it may be more suitable for sperm survival. ● The ​ Penis'​ main function is to deliver semen into the vagina. This should happen during sexual intercourse.

● The ​ Urethra​ is where the semen exits the body, along with urine. The Urethra is a 8 to 10 inch long muscular tube. ● Testes​ , also referred as testicles, produce sperm and testosterone . The sperm are the male gametes, and the testosterone are the male hormones. ● The ​ epididymis ​ is where the sperm are stored. Sperm produced in the testes move into the epididymis to mature, before being passed through the male reproductive organs. ● The ​ scrotum​ is a combination of muscle and skin that surrounds the testes. These sac­like organ regulates the temperature for the testes.

Female Reproductive System: ● The ​ fallopian tubes ​ are a pair of muscular tubes. The fallopian tubes end in a funnel­shaped structure called the infundibulum, which is covered with small finger­like shapes, called fimbriae. The fimbriae are located just outside of the ovaries to pick up released ova and carry them into the infundibulum. Which then takes the egg into the uterus. Every month during ovulation, a mature ovum(egg) is released. It travels from the ovary to the Fallopian tube where it waits to be fertilized before, reaching the uterus. ● Ovaries ​ produce female sex hormones, such as estrogen, progesterone, and ova.

Ova are commonly called eggs, which are the female gametes. Ova are produced from oocyte cells that slowly mature during a woman's life. They reach maturity after puberty. The ovaries are 2 small glands on both sides of the pelvic. They are lateral to the uterus. ● The​ uterus​ is also known as the womb. It provides support and surrounds the developing fetus, during pregnancy. ● The ​ cervix​ acts as a barrier to protect the uterus from infection. Also, it is the opening of the women when giving birth. ● During sexual intercourse, the ​ vagina​ provides a passageway for the sperm. It carries the sperm through the uterus and to the Fallopian tubes. Aside from this, when menstruating the menstrual cycle flow exits via vagina. ● The ​ vulva​ surrounds the external ends of the urethral opening and the vagina.

Puberty

What is the Puberty?

For both genders, puberty is the time your body starts to mature into an adult. During this transition, you will notice changes in your body.

Puberty prepares your body to be capable of sexual reproduction.

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What is the Science Behind Puberty?

When your body is ready to begin puberty, it sends a message to your pituitary gland to release special hormones. You have different hormones, based on whether you're a girl or boy. Girls have hormones called estrogen, and boys have hormones called testosterone. A little while after the message is sent, your body begins to grow pubic hair.

Pubic hair is hair that grows on your genital areas. Also,during puberty you might notice something red pop up onto your face. That is called a pimple. This happens when your body overproduces oil and it gets stuck in your skin follicle. All of these changes are perfectly normal. In addition, individuals begin to grow taller.

Puberty in Girls

Girls tend to hit puberty earlier than boys, around the age of 8-13. The indication that a girl has hit puberty is when she gets her period. This is a common word for her menstrual cycle. Also, during puberty the girl

starts to grow pubic hair and underarm hair . Lastly, her breasts begin to grow and develop.

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Puberty in Boys

Boys commonly experience puberty at the age of 9-15. Boys go through many changes, during their phase of puberty. To begin with, they grow facial, underarm, pubic, and sometimes, chest hair. Also, you will begin your growth spurt. During puberty, expect your penis and testes to grow. Also, random erections become common. Erections are when a boy gets sexually excited, and blood rushes to his penis. This causes the penis to rise, and release semen.

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Emotional States During Puberty

Boys

Girls

● Emotional Ups and Downs in daily life

● Mood Swings During Menstrual Cycle

● Feeling self conscious

● Irritated easily

● Getting Sexual Feelings

● Getting Sexual Feelings

Both genders experience mood changes, when progressing through puberty. You might feel sad on moment and happy the next. Mood swing are usually minor, if they affect your everyday life and function seek medical help.

What Does One Need To Do When They Hit Puberty?

When you have hit puberty, you will need to start using deodorant. This is because you body will now start to sweat more often, and release toxins.

Picture courtesy of Clip Art If you any further questions about puberty, ask a parent, doctor, or trusted adult.

Menstrual Cycle

What is the menstrual cycle?

It is a series of changes a woman's body goes through, to prepare for pregnancy.

When does it happen?

You get your first period between the ages of 11­14.

How long does a period last?

A regular period last between 4­7 days. The menstrual cycle happens on an average of every month. At the age of 50, you will reach menopause.

What are the phases of the menstrual cycle?

Follicular Phase: This is where the mature egg is waiting to be released.

Ovulation: The mature egg is released into the Fallopian tubes and is waiting to be fertilized.

Luteal Phase: The 13­15 day window for the egg to be fertilized, which allows you to become pregnant.

When an egg is not fertilized, it is released through a blood flow that lasts 4­7 days.

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Fertilization and Childbirth

Fertilization:​ The process in which a sperm joins with an egg.

When the male ejaculates sperm through the penis and into the vagina of the female, thousands of sperm swim into the Fallopian tubes, which is where the egg is present.

The egg has binding sites; the sperm attach to these specific locations. When the sperm is attached, the sperm releases enzymes to break down a specific layer of the egg. Both gametes, or haploid cells, join and form a diploid, or something with two sets of chromosomes.

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Did you know that an egg cell has granules that attach to the surface of the egg to stop other sperms from entering the egg after one already has?

Zygote: ​ A zygote is a fertilized egg.

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Mitosis of the Zygote

When the zygote is still in the Fallopian tubes, it begins to go through mitosis, which is cell division. Each time the cell divides, the total number of cells doubles. By four days, the zygote is called a ​ morula​ , and it has about 64 cells.

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3 Early Stages of Development: ● Implantation: A cavity forms in the center of the morula. This causes the morula to have a blastocyst (inner cavity). This blastocyst attaches itself to the uterus of the mother. The embryo releases enzymes to help with the process. ● Gastrulation: This is the migration of cells, which causes three layers of the blastocyst to be created. The three cell layers are the ectoderm(will eventually become the skin and nervous system), the endoderm (will eventually form the lining of the digestive system

and other digestive organs), and the mesoderm (which will form many internal tissues and organs). ● Neurulation: The development of the nervous system. Slowly, parts of the mesodermal tissue begin to form parts of nervous system, like the spine and brain.

Implantation

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Gastrulation

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Neurulation

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Membranes of the Embryo

The chorionic villi and lining of the uterus create the ​ placenta​ . The placenta is the organ of the embryo that allows it to respire, excrete, and get nourishment through the mother. The placenta is the connection between the mother and the embryo.

Membranes form to protect the developing embryo. The two membranes that form are the ​ amnion ​ and the ​ chorion.​ The chorion, by the end of the third week of development, begins to form chorionic villi. (Villi are small things that stick out from the embryo).

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Fetus

The fetus is the embryo after eight weeks of development. Most of its organs and tissues are formed, its muscular system is almost completely developed, has a mass of an average of 28 grams, and a probable height for the fetus is 8 centimeters long.

The umbilical chord is also formed. It is made up of two arteries and one vein. It connects the fetus to the placenta.

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More Development!

4th­6th months after fertilization: a. Tissues become more specialized and begin to work. b. The heart can be heard with a stethoscope. c. Hair begins to grow on the fetus's skin. d. Bone replaces the cartilage.

6th­9th months after fertilization: a. Lungs and organs go through changes that help prepare them to live outside of the uterus. b. Fetus can control body temperature. c. The central nervous system(brain and spinal cord) and lungs finish developing.

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Childbirth

How does childbirth begin?

The hormone, oxytocin, is released from a gland in the mother's body. This hormone causes labor to occur because it affects the large involuntary muscles of the wall of the uterus.

How does childbirth occur?

The cervix of the mother begins to open so that it is large enough for the baby's head to go through. Then, a sac breaks in the uterus, and fluid begins to come out of the vagina. The baby comes out, usually head first, through the vagina.

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