Unit I Gen Ed 10 PDF

Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION UNIT I...

Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION UNIT I Page | 1 INTRODUCTION Overview Human reproduction involves creating new individuals through the joining of male and female reproductive cells. This starts with the fertilization of an egg by a sperm, forming a zygote. The zygote then goes through various stages of development, including cell division and differentiation, ultimately becoming an embryo and then a fetus. This process is controlled by the complex reproductive systems and hormones in both males and females. Besides the biological aspects, human reproduction includes important social, ethical, and cultural elements. Issues such as family planning, access to reproductive healthcare, and cultural views on reproduction play significant roles. Advances in reproductive technologies, such as in vitro fertilization (IVF) and genetic screening, have introduced new opportunities and challenges. Understanding human reproduction is crucial for improving reproductive health, managing population growth, and navigating the ethical issues that arise from reproductive decisions. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Lesson Proper Page | 2 What is Reproduction? Reproduction is a biological process in which an organism produces offspring that are genetically similar to itself. This process ensures the continuation of species across generations, playing a crucial role in life on Earth. Let's explore reproduction in detail, including its various types and the modes of reproduction found in plants and animals. There are two types of reproduction: 1. Asexual Reproduction Asexual reproduction is a process in which a single parent generates offspring without the need for gametes (sperm and egg cells). The offspring are genetic replicas of the parent, possessing the same set of genes and exhibiting no genetic variation. This form of reproduction is commonly seen in plants, fungi, and certain animals, including bacteria and some invertebrates. It allows for quick population expansion and does not require a mate, which can be beneficial in stable environments. However, the absence of genetic diversity among the offspring can make them more susceptible to diseases and nutrient deficiencies. Methods of Asexual Reproduction: Binary Fission: This is a type of asexual reproduction frequently found in bacteria and single-celled organisms, where a single cell splits into two genetically identical daughter cells. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION An example of binary fission is bacteria like Escherichia coli. In this process, the bacterial cell divides into two identical cells, each with a copy of the original genetic material. Page | 3 Another example is the amoeba, a single-celled organism that reproduces by splitting into two new amoeba. Budding: This reproductive process is found in yeast and some invertebrates, where a new organism develops as an outgrowth from the body of the parent and eventually detaches to become a separate individual. Fragmentation: Common in starfish and certain plants, where a new organism grows from a fragment of the parent. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Sporogenesis: In this type of reproduction, a new organism grows from the spores. These can be created without fertilization and can spread through wind and animals. Page | 4 2. Sexual Reproduction Sexual reproduction is the process of producing offspring through the union of male and female gametes. This can occur between individuals of different sexes or, in some cases, within a single organism. Unlike asexual reproduction, which results in offspring genetically identical to the parent, sexual reproduction generates offspring with diverse genetic traits. This genetic diversity arises because each gamete carries a unique combination of genes, leading to varied genetic outcomes in the offspring. This method of reproduction is generally more complex and time-consuming than asexual reproduction, involving stages such as gamete production, mating, and fertilization. Despite its complexity, sexual reproduction promotes genetic variation, which can aid organisms in adapting to changing environments and enhance their evolutionary success. Many multicellular organisms, including humans, depend on sexual reproduction for the continuation and advancement of their species. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Cell division is a crucial biological process that enables organisms to grow, repair damaged tissues, and reproduce. In this process, a single parent cell splits into two daughter cells, each with a complete set of genetic material. Page | 5 Primary Types of Cell Division Mitosis results in the creation of two daughter cells, each with the same number of chromosomes as the original parent cell. This process is vital for growth, tissue repair, and asexual reproduction. During mitosis, the cell undergoes a single division where chromosomes are duplicated, aligned, and then separated into two identical sets. The stages of mitosis—prophase, metaphase, anaphase, and telophase—ensure accurate replication and distribution of genetic material to the daughter cells. Mitosis occurs in somatic cells, which are responsible for growth, repair, and asexual reproduction. In contrast, meiosis is a specialized cell division process that produces four daughter cells, each containing half the chromosome number of the parent cell. This process is critical for sexual reproduction and involves two sequential divisions: meiosis I and meiosis II. Initially, meiosis separates homologous chromosomes, followed by the division of sister chromatids. Meiosis also promotes genetic diversity through mechanisms like crossing over and independent assortment, which enhance genetic variation in offspring. Meiosis takes place in germ cells, which produce gametes such as sperm and eggs. In summary, mitosis generates cells that are genetically identical to the parent cell, supporting growth and repair, while meiosis produces genetically varied gametes, essential for reproduction and evolutionary processes. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Important Terms in Cell Division Nucleus: The nucleus is a central organelle in cells, housing the DNA and controlling key cellular functions, including growth, metabolism, Page | 6 and reproduction, by regulating gene expression. Chromatin: Chromatin consists of DNA and associated proteins within the nucleus. Its primary role is to compact the DNA into a manageable structure that fits inside the nucleus, while also influencing the accessibility of genes for transcription. Chromosomes: Chromosomes are tightly coiled entities made of DNA and proteins that carry the cell's genetic information. They become visible during cell division and are essential for ensuring the precise allocation of genetic material to daughter cells. Chromatids: Chromatids are the two identical halves of a replicated chromosome, joined together at the centromere. In the process of cell division, these chromatids are divided and become individual chromosomes in the newly formed daughter cells. Centromeres: The centromere is the region on a chromosome where the two sister chromatids are connected. It serves as the attachment point for spindle fibers during cell division, helping to ensure the proper separation of chromatids. Centrioles: Centrioles are tiny, cylindrical structures composed of microtubules. They play a crucial role in organizing the spindle fibers, which are necessary for the proper segregation of chromosomes during cell division. Centrosome: The centrosome is an organelle located near the nucleus that acts as the main organizing center for microtubules in animal cells. It plays a vital role in assembling the spindle apparatus necessary for cell division. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Spindle fibers: Spindle fibers are protein structures that develop during cell division. They connect to chromosomes at the centromeres Page | 7 and are crucial for separating chromatids, thereby ensuring that chromosomes are accurately distributed to each daughter cell. Cytoplasm: The cytoplasm is the semi-fluid substance within the cell membrane, excluding the nucleus. It contains various organelles and is where many cellular activities, including metabolism and protein synthesis, take place. Daughter cells: Daughter cells are the two new cells produced when a single parent cell divides. During mitosis, these daughter cells are genetically identical to each other and to the original parent cell. Germ Cells: Germ cells are cells that create reproductive cells called gametes. Germ cells are located only in the gonads and are called oogonia in females and spermatogonia in males. In females, they are found in the ovaries and in males, in the testes. During oogenesis, germ cells divide to produce ova, or eggs, in females. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Gametes: These are the mature reproductive cells produced from germ cells. Gametes are haploid, which means they have only one set of chromosomes. In males, the gametes are sperm cells, and in females, they are egg cells. Gametes combine during fertilization to form a new organism, carrying genetic information from both parents. Haploid: Refers to a cell that contains a Page | 8 single set of chromosomes, which is half the number found in diploid cells. In humans, haploid cells have 23 chromosomes. These cells are gametes (sperm and egg cells) and are involved in reproduction. Diploid: Refers to a cell that contains two sets of chromosomes, one inherited from each parent. In humans, diploid cells have 46 chromosomes arranged in 23 pairs. Most cells in the body are diploid and participate in normal growth and cellular functions. Mitosis Cells go through different phases that include growth. DNA replication, cell division, and the production of two genetically identical daughter cells. This sequence is known as the cell cycle which has two main phases. Interphase and the mitotic phase, also known as mitosis. Interphase Interphase is the longest phase of the cell cycle, accounting for about 90 percent of the total cycle. During interphase, a cell recovers from the previous division and performs normal functions. It grows in size by forming more organelles and replicating its DNA resulting in the duplication of cells chromosomal matter. Eukaryotic cells that are actively dividing undergo a series of stages called the cell cycle. This cycle includes two gap phases (G1 and G2), a synthesis phase (S phase) where the genetic material is replicated, and a mitotic phase (M phase) during which mitosis divides the genetic material and the cell splits into two daughter cells. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Next, the cell will go through mitosis, which includes the division of the nucleus and then the division of the cytoplasm called cytokinesis. Mitosis also has several stages Prophase, Metaphase, Anaphase, and Telophase which are finally followed by cytokinesis. Page | 9 Prophase During Prophase the chromatin condenses into visible chromosomes and the nuclear membrane disintegrates. The centrosomes move to the opposite pole of the cell as a spindle fiber form. The spindle fibers attach to the centromere of the chromosomes. Metaphase Metaphase is characterized by the alignment of chromosomes at the metaphase plane. An imaginary plane in the middle of the cell. The spindle fibers ensure each chromosome is properly aligned. Anaphase Anaphase begins when a sister chromatid of each chromosome separates in a pole toward opposite poles of the cells by the spindle fibers. Once the chromosomes reach the poles, the cell elongates. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Telophase Page | 10 During telophase, the chromosomes decondensed, and new nuclear membranes form around each set. The spindle fibers are disassembled and the cell prepares for cytokinesis. Cytokinesis, which sometimes begins during telophase, is the cell cycle's final stage. Cytoplasm divides which forms two genetically identical daughter cells. After cytokinesis, the two daughter cells enter interphase and the cell cycle begins again. Meiosis Many organisms transfer their genes to offspring through sexual reproduction, which starts with the fusion of two gametes to create a genetically unique embryo. This embryo develops into an adult, passing genetic information to its progeny. Gametes are produced via meiosis. Germline cells are those that undergo meiosis to form gametes. In diploid organisms, these germline cells contain two copies of each chromosome. Germline cells produce haploid gametes through meiosis, each with a single set of chromosomes. When these haploid gametes combine, they form a diploid embryo that will mature into an adult. Meiosis is a critical part of the germline cell life cycle. Similar to mitosis, germline cells first go through interphase, consisting of the G1, S, and G2 phases. During the S phase, DNA replication occurs, resulting in duplicated chromosomes known as sister chromatids. These chromatids stay joined until the second division of meiosis. Meiosis involves two rounds of cell division: 1. Meiosis I: This division results in two unique daughter cells, each with half the chromosome number of the original germline cell. 2. Meiosis II: This division produces four haploid cells, each containing one copy of each chromosome. These haploid cells are the gametes that participate in sexual reproduction. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Page | 11 Meiosis I begins with Prophase I, where DNA condenses into chromosomes, and duplicated sister chromatids pair up and connect at the centromere. These pairs undergo synapsis, forming a complex of homologous chromosomes. During this phase, crossing over (recombination) occurs, exchanging chromosomal material between chromatids, which contributes to genetic diversity. The nuclear membrane breaks down, centrosomes move to opposite poles, and microtubules attach to chromosomes. In Metaphase I, paired chromosomes align at the cell's equator randomly, leading to various combinations of chromosomes. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION During Anaphase I, homologous chromosomes separate and move to Page | 12 opposite poles of the cell, while sister chromatids remain attached at their centromeres. The final stages, Telophase I and cytokinesis, result in the formation of two daughter cells. Meiosis II resembles mitosis. In Prophase II, chromosomes condense again, the nuclear envelope disintegrates, and spindle fibers form. Unlike Prophase I, there is no synapsis or crossing over in Prophase II. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Page | 13 In Metaphase II, chromosomes align at the cell's equator randomly. During Anaphase II, sister chromatids are separated and pulled to opposite poles, with microtubules assisting in the process. Finally, in Telophase II and cytokinesis, the cell divides into four unique haploid cells. These gametes can then fuse during fertilization to form a diploid embryo, which will develop through numerous mitotic divisions into a new adult. Mitosis vs. Meiosis: A Comparative Table “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Mitosis and meiosis are two fundamental processes of cell division in eukaryotic organisms. While both involve the division of a parent cell into daughter cells, they differ significantly in their outcomes and functions. Here's a table highlighting the key differences between these two processes: Page | 14 Feature Mitosis Meiosis Growth, repair, and asexual Sexual reproduction, genetic Purpose reproduction diversity Cell Type Somatic cells (body cells) Germ cells (sex cells) Number of Divisions One Two Number of Daughter Cells Two Four Haploid (n) - half the Chromosome Number in Diploid (2n) - same as parent number of chromosomes as Daughter Cells cell the parent cell Genetically different from Genetic Identity of Genetically identical to the the parent cell and each Daughter Cells parent cell other Homologous Chromosome Does not occur Occurs during prophase I Pairing Occurs during prophase I, exchanging genetic material Crossing Over Does not occur between homologous chromosomes Centromere Splitting Occurs during anaphase Occurs during anaphase II “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Feature Mitosis Meiosis Occurs during prophase I, forming tetrads (bivalents) Page | 15 are paired homologous chromosomes, consisting of Synapsis Does not occur four chromatids, that form during prophase I of meiosis and are key players in the process of genetic combination. Occurs during prophase I, Tetrad Formation Does not occur consisting of four chromatids Chiasmata or chiasma (singular) are the points where homologous Present during prophase I chromosomes physically Absent and metaphase I, indicating cross over and exchange crossing over genetic material during meiosis. Occurs before meiosis I, but Interphase Occurs before each division not before meiosis II Occurs once before the Occurs once before meiosis DNA Replication division I, but not before meiosis II Duration Relatively shorter Relatively longer Skin cell division, wound Sperm and egg cell Examples healing formation “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Key Takeaways: Mitosis produces two genetically identical daughter cells, maintaining the chromosome number of the parent cell. It is essential for growth, repair, and asexual reproduction. Meiosis produces four genetically diverse daughter cells, each with half the chromosome Page | 16 number of the parent cell. This process is crucial for sexual reproduction and genetic variation. Further Exploration: Explore the specific stages of mitosis and meiosis (prophase, metaphase, anaphase, telophase) to gain a deeper understanding of the mechanisms involved. Investigate the role of meiosis in genetic diversity and its implications for evolution. Research the potential consequences of errors in mitosis and meiosis, such as cancer and aneuploidy. What is Genetics? Genetics is the science that studies genes and how they are inherited from one generation to the next. Genes are responsible for determining various characteristics, such as why one child may have blonde hair like their mother while another has brown hair like their father. This field also explores why certain genetic conditions may appear in families and how sex is determined in offspring. What are Genes? Genes are small segments of DNA (deoxyribonucleic acid) found within every cell. They are so tiny that only a powerful microscope can reveal them. DNA is composed of four chemicals that pair in different ways to form codes for genes. Each individual has around 20,000 genes, which influence traits like eye color, body structure, and sex. DNA (deoxyribonucleic acid) is composed of four chemical bases that pair in specific ways to form the genetic code. These bases are: 1. Adenine (A) “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION 2. Thymine (T) 3. Cytosine (C) 4. Guanine (G) In the structure of DNA, these bases pair in a specific way: Adenine (A) pairs with Thymine (T) Page | 17 Cytosine (C) pairs with Guanine (G) These base pairs form the "rungs" of the DNA double helix, and the sequence of these base pairs creates the genetic code that determines the structure and function of genes. The order of these bases in the DNA sequence is what encodes the instructions for building proteins and other molecules essential for life. What are Alleles? Alleles are different versions or forms of the same gene that exist at the same position, or locus, on a chromosome. Alleles can vary in sequence and function, leading to different traits or characteristics in an organism. For example, a gene responsible for eye color might have different alleles that result in blue, brown, or green eyes. Dominant and Recessive Alleles: Dominant Alleles: These alleles express their traits even if only one copy is present (heterozygous). Dominant alleles are generally denoted by capital letters(e.g., "B"). Recessive Alleles: These alleles express their traits only when two copies are present (homozygous). They are represented by lowercase letters (e.g., "b"). “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION Homozygous and Heterozygous: Homozygous: An individual has two identical alleles for a gene (e.g., BB or bb). Heterozygous: An individual has two Page | 18 different alleles for a gene (e.g., Bb). Genotype and Phenotype Genotype: The genetic makeup of an organism. For example, a plant with a genotype "RR" for flower color will have red flowers, assuming "R" is the dominant allele for red. Phenotype: The observable/physical characteristics of an organism, resulting from the genotype. For instance, a plant with "RR" or "Rr" will show red flowers, while "rr" will produce white flowers. Hormones Hormones are chemical messengers produced by glands in the endocrine system that travel through the bloodstream to tissues and organs, regulating various bodily functions. Hormones are produced by different glands, including the pituitary gland, thyroid gland, adrenal glands, and reproductive organs (ovaries and testes), among others. Key Functions of Hormones: 1. Regulation of Growth and Development: Hormones like growth hormone (GH) are crucial for physical development, including bone growth and muscle development. 2. Metabolism Control: Hormones such as insulin and thyroid hormones regulate how the body uses and stores energy from food. 3. Mood and Emotional Regulation: Hormones like serotonin (Serotonin is a neurotransmitter, often referred to as the "feel-good" chemical, that plays a crucial role in mood regulation and overall mental well-being) and cortisol (Cortisol is a steroid hormone, often called the "stress hormone," produced by the adrenal glands in response to stress and low blood-glucose concentration) influence mood, stress response, and emotional well-being. These two hormones interact in stress response and emotional regulation. Chronic stress and elevated cortisol levels can reduce serotonin levels, potentially leading to mood disorders such as anxiety and depression. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION 4. Homeostasis Maintenance: Hormones help maintain the body’s internal balance, such as regulating blood pressure, blood sugar levels, and fluid balance. 5. Immune System Regulation: Some hormones, like corticosteroids, help regulate immune responses and inflammation. 6. Reproductive Functions: Reproductive hormones such as estrogen, progesterone, and Page | 19 testosterone are essential for sexual development, reproduction, and the menstrual cycle. Reproductive hormones are chemicals produced by glands in the body that regulate various aspects of the reproductive system, including development, sexual function, the menstrual cycle, and pregnancy. Here's an overview of key reproductive hormones, their functions, and where they are produced: Key Reproductive Hormones: 1. Estrogen is a steroid hormone associated with the female reproductive organs and is responsible for developing female sexual characteristics. Estrogen or estradiol is the most common form of estrogen hormone for FDA-approved treatment as hormone replacement therapy (HRT) in managing symptoms associated with menopause. o Location: Mainly produced in the ovaries; smaller amounts are made in the adrenal glands and fat tissue. o Functions: ▪ Regulates the menstrual cycle and helps prepare the uterus for pregnancy. ▪ Aids in the development of female secondary sexual characteristics (e.g., breasts). ▪ Supports the health of reproductive tissues. 2. Progesterone is an endogenous steroid hormone that is commonly produced by the adrenal cortex as well as the gonads, which consist of the ovaries and the testes. Progesterone is also secreted by the ovarian corpus luteum during the first ten weeks of pregnancy, followed by the placenta in the later phase of pregnancy. o Location: Primarily produced by the ovaries and the placenta during pregnancy. o Functions: ▪ Prepares the uterine lining for implantation of a fertilized egg and supports pregnancy. ▪ Works with estrogen to regulate the menstrual cycle. 3. Testosterone is the primary male hormone regulating sex differentiation, producing male sex characteristics, spermatogenesis, and fertility. Testosterone's effects are first seen in the fetus. During the first 6 weeks of development, the reproductive tissues of males and females are identical. o Location: Mainly produced in the testes in males and in smaller amounts by the ovaries and adrenal glands in both sexes. o Functions: ▪ Drives the development of male secondary sexual characteristics, such as increased muscle mass and deeper voice. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION ▪ Essential for sperm production and male libido. 4. Follicle-Stimulating Hormone (FSH) is a hormone your pituitary gland makes and releases that plays a role in sexual development and reproduction. It affects the function of ovaries and testicles. Despite its name, follicle-stimulating hormone doesn't directly Page | 20 affect your hair follicles or hair growth. o Location: Produced by the pituitary gland in the brain. o Functions: ▪ Promotes the growth and development of ovarian follicles in females. ▪ Stimulates the production of sperm in males. 5. Luteinizing Hormone (LH) is a chemical in your body that triggers important processes in your reproductive system. LH spurs ovulation and helps with the hormone production needed to support pregnancy. Your provider may order a test to check your LH levels if you have fertility issues or irregular menstruation. o Location: Also produced by the pituitary gland. o Functions: ▪ Triggers ovulation and the release of an egg from the ovary in females. ▪ Stimulates testosterone production in males. 6. Gonadotropin-Releasing Hormone (GnRH) plays a crucial role in regulating the reproductive system. It is released in a pulsatile manner from the hypothalamus, which then controls the secretion of two key hormones from the pituitary gland: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These gonadotropins are essential for managing the functions of the gonads, including the production of sex hormones and the maturation of gametes, which are the eggs in females and sperm in males. The precise timing and frequency of GnRH pulses are critical for proper reproductive function. o Location: Produced by the hypothalamus in the brain. o Functions: ▪ Regulates the release of FSH and LH from the pituitary gland, which are critical for the reproductive cycle. 7. Human Chorionic Gonadotropin (hCG) is a hormone produced primarily by syncytiotrophoblastic cells of the placenta during pregnancy. The hormone stimulates the corpus luteum to produce progesterone to maintain the pregnancy. Smaller amounts of hCG are also produced in the pituitary gland, the liver, and the colon. o Location: Produced by the placenta during pregnancy. o Functions: ▪ Helps maintain the corpus luteum, which is crucial for producing progesterone in early pregnancy. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph  Republic of the Philippines NUEVA ECIJA UNIVERSITY OF SCIENCE AND TECHNOLOGY San Isidro Campus, San Isidro, Nueva Ecija, Philippines ISO 9001:2015 CERTIFIED COLLEGE OF EDUCATION 8. Prolactin is a polypeptide hormone responsible for lactation, breast development, and hundreds of other actions needed to maintain homeostasis. The chemical structure of prolactin is similar to the structure of growth and placental lactogen hormones. o Location: Secreted by the pituitary gland. o Functions: Page | 21 ▪ Stimulates milk production in women after childbirth. ▪ Involved in reproductive health and regulation. 9. Oxytocin is a natural hormone that manages key aspects of the female and male reproductive systems, including labor and delivery and lactation, as well as aspects of human behavior. Your hypothalamus makes oxytocin, but your posterior pituitary gland stores and releases it into your bloodstream. o Location: Produced by the hypothalamus and released by the pituitary gland. o Functions: ▪ Induces uterine contractions during labor. ▪ Facilitates milk release during breastfeeding and plays a role in social bonding. These hormones are interconnected and work together to regulate the reproductive processes, ensuring proper reproductive health and function in both males and females. “Nourishing the mind, nurturing the heart, leading the Future “ Telefax No. (044) 463-0226 [email protected] www.neust.edu.ph