Reproductive and Endocrine Systems - Science Reviewer PDF

**THE REPRODUCTIVE SYSTEM** The system involved in sexual reproduction is called the reproductive system. There is a striking difference between the male and female reproductive system, although they also share a number of similarities. For example, the reproductive organs of the male and female ar...

**THE REPRODUCTIVE SYSTEM** The system involved in sexual reproduction is called the reproductive system. There is a striking difference between the male and female reproductive system, although they also share a number of similarities. For example, the reproductive organs of the male and female are developed from the same embryological structures, and some hormones are commonly found in both male and female, in varying quantities and produce different responses. The picture shows the main parts of the male reproductive system. The cross-sectional side view of the reproductive system shows that certain parts of the male reproductive system are also part of the excretory system. +-----------------------------------+-----------------------------------+ | Part | Function | +===================================+===================================+ | Testis | Produces sperm cells. | +-----------------------------------+-----------------------------------+ | Scrotum | Sac of skin that holds the | | | testis. | +-----------------------------------+-----------------------------------+ | Penis | Deposits sperm into the vagina | | | during mating. | +-----------------------------------+-----------------------------------+ | Vas deferens (tube) | Carries sperm from testis to | | | urethra. | +-----------------------------------+-----------------------------------+ | Urethra | Carries sperm and urine out of | | | the body. | +-----------------------------------+-----------------------------------+ | Glands | Provide liquid in which sperm can | | | swim. | | a. Seminal vesicle | | | | - Secretes a fluid that makes | | b. Prostate gland | up most of the components of | | | the semen. | | c. Bulbourethral gland | | | | - Secretes a slightly alkaline | | | milky fluid that is | | | discharged as part of the | | | semen. | | | | | | - Secretes a thick and clear | | | mucus that lubricates and | | | neutralizes the any trace of | | | acidic urine in the urethra. | +-----------------------------------+-----------------------------------+ The female reproductive system has the following functions: 1. Produces female sex cells. 2. Receives sperm cell from the male. 3. Nurtures the development of and provides nourishment for the new individual. The picture shows the front view of the female reproductive system. The female reproductive system consists of the ovaries, oviducts (Fallopian tubes), uterus, vagina, and external genitalia. The internal reproductive organs of the female are located within the pelvis, between the urinary bladder and rectum. The uterus and the vagina are in the middle part, with an ovary on each side of the uterus. Part Functions --------- --------------------------------------------------------------------------------------- Ovary Produces egg cells. Oviduct Serves as passageway of eggs from the ovary to the uterus; site of egg fertilization. Uterus Serves as site of egg implantation; is where the fertilized egg develops. Vagina Receives the penis of male during mating. Puberty involves the onset of sexual maturity and the ability to reproduce. When a female reaches puberty, egg cells start to develop in her ovaries that produce the sex cells. It is also the time when the body develops the capacity to conceive. **THE** **ENDOCRINE SYSTEM** The endocrine system is composed of glands that secrete different types of hormones that affect almost every cell, organ, and function of our body. It is essential in regulating growth and development, metabolism, as well as reproductive process and mood. Endocrine glands secrete chemicals known as hormone into the bloodstream, which carries them throughout the body. When a hormone in the blood reaches the target organ, it produces a notable effect. The endocrine system sends signals all over the body, much like the nervous system, but unlike the instant responses activated by the nervous system, the affects can take a few hours or even weeks. **ENDOCRINE GLANDS AND THEIR HORMONES** This endocrine system contains a group of glands that release hormones into the body. The following table list all the major glands in the body, with their functions, locations, and the hormones they release. +-----------------+-----------------+-----------------+-----------------+ | Gland | Location | Hormones | Function | | | | Released | | +=================+=================+=================+=================+ | Pituitary | at the base of | Oxytocin, | Stimulates | | | the brain | | growth, and | | | | Vasopressin, | controls the | | | | | functions of | | | | Growth Hormone, | other glands | | | | Adrenocorticotr | | | | | opic | | | | | Hormone (ACTH), | | | | | | | | | | Prolactin, | | | | | Luteinizing | | | | | Hormone, | | | | | Follicle | | | | | Stimulating | | | | | Hormone (FSH) | | +-----------------+-----------------+-----------------+-----------------+ | Thyroid | below the voice | Thyroxin, | Regulates body | | | box | Calcitonin | metabolism, and | | | | | causes storage | | | | | of calcium in | | | | | bones | +-----------------+-----------------+-----------------+-----------------+ | Parathyroid | in the neck | Parathyromone | Controls the | | | | | calcium levels | | | | | in your body, | | | | | and normalizes | | | | | bone growth | +-----------------+-----------------+-----------------+-----------------+ | Thymus | in front of the | Thymosin | Enables the | | | heart | | body to produce | | | | | certain | | | | | antibodies | +-----------------+-----------------+-----------------+-----------------+ | Adrenal | on top of the | Adrenaline | Prepares the | | | kidneys | | body for | | | | | action, | | | | | controls the | | | | | heart rate and | | | | | breathing in | | | | | times of | | | | | emergency | +-----------------+-----------------+-----------------+-----------------+ | Pancreas | between the | Insulin, | Regulates blood | | | kidneys | Glucagon | sugar levels | +-----------------+-----------------+-----------------+-----------------+ | Reproductive | lower abdomen | Androgen, | Control | | | | Testosterone | maturation and | | - Testes | lower abdomen | | male | | (males) | | Estrogen, | characteristics | | | | Progesterone | | | - Ovaries | | | Influence | | (females) | | | female traits, | | | | | and support | | | | | reproductive | | | | | function | +-----------------+-----------------+-----------------+-----------------+ The endocrine system consists of glands that secrete chemicals called hormones to control various body processes. This control system usually brings about slow changes in the body because chemical messengers move more slowly than the nerve impulses. The major glands in the body are the pituitary, thyroid, parathyroid, thymus, adrenal, pancreas, ovaries, and testes. **EFFECTS OF HORMONES IN THE BODY** Several processes in the body are coordinated by hormones which regulate and balance the working of organs, tissues, and cells. The endocrine system influences how your heart beats, how your bones and tissues develop, and even your capacity to have a baby. It plays an essential role in the occurrence of disorders such as diabetes, thyroid disease, growth disorders, and/or sexual dysfunction. Both men and women produce hormones in the same areas with one exception, the reproductive glands. Additional male hormones are produced in the testes while female hormones are produced in the ovaries. Some hormones have short-term effects while other hormones have long-term effects such as those that control our growth and the changes at the onset of puberty. During puberty, there are many hormonal changes that happen in your body. One moment you laugh, and then suddenly you feel like crying. Sudden mood swings are relatively caused by the increasing amount of hormones in the body at this stage. It is therefore important to maintain a positive outlook in life and remember that these changes are only temporary and will stabilize with time. Hormones act in very small amounts. If the organ and hormones do not produce the regulated amount of chemicals to your body, it may result in an abnormality of your body. This condition is called hormonal imbalance. An increase or decrease in its amount may have a significant effect in the human body. Hormones affect various processes in the body as they regulate and balance the functioning of organs, tissues, and cells. Hormones have great impact on your growth, appearance, emotions, and reproductive functions. These determine whether or not you develop disorders such as diabetes, thyroid disease, growth disorders, or sexual disfunction. Hormones act in very small amounts. An increase or decrease in hormonal levels may result in body disorder due to hormonal imbalance. **HORMONES INVOLVED IN FEMALE AND MALE REPRODUCTIVE SYSTEM** Hypothalamus is the brain regulatory center for maintaining homeostasis receiving nerve signals. It gives direction to the pituitary gland. Gonadropin-releasing hormone (GnRH) -- are hormones that are secreted by the hypothalamus stimulating the pituitary gland to release two hormones namely Luteinizing Hormone (LH) and the Follicle Stimulating Hormone (FSH). LH stimulates gonads to produce sex hormones and the release of the egg cell from the female ovary. FSH stimulates the sex organs to produce gametes or sex cells. Hypothalamus and pituitary gland affect the male and female reproductive system to secrete sex hormones controlling the sex characteristics. Estrogen is the primarily female sex hormone that stimulates sex drive and progesterone hormone released by luteum in the ovary. It plays vital roles in the menstrual cycle and maintaining the stages of pregnancy. It regulates and maintains homeostasis and controls the growth of and release of eggs from the ovaries and helps prepare the uterus so the baby can grow in it. **DNA AND RNA** Component molecules 1. The DNA molecule is composed of three types of component molecules: phosphate group, the sugar deoxyribose, and the bases adenine, thymine, cytosine, guanine (A, T, C, G). Nucleotides 2. There are three molecules that form the basic building block of DNA, the nucleotides. Each nucleotide is composed of one phosphate group, one sugar molecule, and one of the four bases -- in the example. Across the strands of the helix, A always pairs with T, and G with C. Ribonucleic Acid, like DNA, is a nucleic acid. However, RNA structure differs from DNA structure in three ways. First, RNA is single stranded -- whereas DNA is double stranded. Second, the sugar in RNA is ribose; DNA has deoxyribose. Finally, both DNA and RNA contain four nitrogenous bases, but instead of thymine, RNA contains a similar base called uracil (U). The major types of RNA include: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). Basis of Comparison DNA RNA ---------------------- ------------- ------------ Number of strand 2 1 Location in the cell nucleus cytoplasm Type of sugar deoxyribose ribose Nitrogenous bases A, T, C, G A, U, C, G Deoxyribonucleic Acid (DNA) - The molecular blueprint of life. - It contains a vast amount of information that controls the cell's internal functions and dictates the organism's physical characteristics. - The genetic information contained in the DNA is also hereditary and transferable. - It also instructs the creation of protein in the cells. - The information, in the form of genetic codes, inside the DNA are translated to form proteins. Ribonucleic Acid (RNA) - A single strand molecular structural similar to DNA. DNA RNA ------------------------- ----------------------------------------- ---------------------------------------- Sugar (Strand Backbone) deoxyribose ribose Nucleic Base Pair adenine, thymine, cytosine, and guanine adenine, uracil, cytosine, and guanine Three types of RNA: 1. messenger RNA (mRNA) -- brings information from the DNA in the nucleus to the protein manufacturing area, the cytoplasm. In the cytoplasm, the mRNA becomes the template information to make proteins. 2. ribosomal RNA (rRNA) -- ribosomes, made of rRNA and ribosomal proteins hold tightly into the mRNA using its information to assemble the amino acids in correct order. 3. transfer RNA (tRNA) -- supplies amino acids to the ribosome to be assembled as protein. - The sequence of nucleotides in DNA directs the order of nucleotides in messenger RNA in a process called transcription. - DNA directs the production of proteins and determines the formation of mRNA. The order of bases of mRNA determines the protein synthesized. - The process of converting the information in messenger RNA into a sequence of amino acids that make a protein is known as translation. Proteins such as enzymes are mostly amino acids chained together in a certain order. Each group of three nucleotide bases represents a codon stop signal. This code is picked up by the mRNA and is carried from the nucleus to cytoplasm. The codon has its complement anticodon in tRNA. Each amino acid that will form the protein molecule to be synthesized is determined by the triplet code of codon on the mRNA.