A
Acrosome reaction - the reaction by which a sperm cell breaks through the protective layer (zona pellucida) surrounding an egg cell.
Source: Alberts B, Johnson A, Lewis J, Raff M, Roberts K and Walter P. Molecular biology of the cell. 4th ed. Oxford University Press; 2003.
Amniocentesis - an invasive prenatal test in which amniotic fluid (in which the baby floats) is extracted by means of a hollow needle inside the uterus. Read more about prenatal invasive testing here.
Source: Roca P. Amniocentesis. In: Ramus RM, Talavera F (eds.). Medscape. 2018. Available from: https://emedicine.medscape.com/article/1997955-overview [Accessed September 3rd, 2022]
Amnion - the inner membrane of the placenta. This membrane encloses the amniotic sac, which is the space filled with fluid that the baby floats in. The amnion functions as a shock absorber.
Source: Moore KL, Persaud TVN, Torchia MG. The Developing Human. 10th ed. Philadelphia, USA: Elsevier; 2016.
Amniotic fluid – this is the fluid inside the placenta that the embryo or fetus floats in. It helps absorb shocks to protect the baby. It’s also important for the baby’s development, because they breathe in the fluid and swallow it. This helps develop the lungs and the digestive system.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Aneuploidy - abnormal number of chromosomes in a cell. This could be more (e.g. trisomies = 3 chromosomes) or fewer (e.g. monosomy = 1 chromosome only) than the usual two chromosomes, in one or more specific pairs.
Source: O’Connor C. Chromosmal Abnormalities: Aneuploidies. Nature Education. 2008;1(1):172.
Anterior pituitary gland - see Pituitary gland.
Antibody - antibodies are produced by your immune cells in response to antigens to fight off pathogens. They can bind to the antigen and flag it as a foreign substance. The immune system can then recognize all the pathogens that carry this antigen and destroy them. Each antibody is specific for an antigen: the principle is similar to a lock and key. Each key (antibody) only fits one specific lock (antigen).
Source: Ghose T. What are antibodies. Available from: https://www.livescience.com/antibodies.html [Accessed November 30th, 2022]
Antigen - an antigen is a small part of a pathogen that starts the immune response in the body to fight off the pathogen.
Antigens can come from toxins, chemicals, bacteria, viruses and other substances that come from outside of the body. These foreign particles are processed by the body. A specific part of the pathogen (the antigen) is then recognised by the immune system with the help of antibodies. Many pathogens have multiple antigens, so the body often has multiple targets to fight.
Source: National Cancer Institute (NCI). Antibody. Available from: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/antibody [Accessed November 30th, 2022]
Anti-oxidant - this is a substance that prevents the production of so-called “free radicals”, which can damage structures inside cells. They form during complex chemical processes in cells that are important for making energy. They can also form when your cells are damaged, for example due to radiation from the sun. Your body produces its own anti-oxidants, and you can find them in fruits and vegetables as vitamin A, C and E, for example.
Source: Alberts B, Johnson A, Lewis J et al. Molecular Biology of the Cell. 6th ed. New York: Garland Science; 2015.
Apoptosis – this is the process of so-called “programmed cell death”. This means that a cell dies according to a set of rules. The cell is neatly taken apart based on more or less standard steps. Apoptosis is very important during the development of an embryo and fetus, because lots of cells serve a function for only a limited time. It’s also important in many processes in children and adults, for example for removing damaged cells and preventing cancer.
Source: Alberts B, Johnson A, Lewis J et al. Molecular Biology of the Cell. 4th ed. New York: Garland Science; 2002
Autoimmune disorder - a condition where the immune system mistakenly attacks the body's own healthy cells, tissues, or organs, causing inflammation and damage. It can result in a variety of symptoms and often requires treatment to manage symptoms and regulate the immune response.
Source: Richard-Eaglin A, Smallheer BA. Immunosuppressive/Autoimmune Disorders. Nurs Clin North Am. 2018;53(3):319-334. DOI: 10.1016/j.cnur.2018.04.002.
Autosomal chromosomes - all chromosomes which are not sex chromosomes. This means chromosome pairs 1 up to and including 22.
Source: Alberts B, Johnson A, Lewis J et al. Molecular Biology of the Cell. 6th ed. New York: Garland Science; 2015.
B
Biopsy - this is a bit of tissue that a doctor takes from your body, so it can be examined under a microscope to see if anything is wrong with it. This is often done to exclude or confirm cancer.
Source: Biopsy. National Cancer Institute. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/biopsy [Accessed February 12th, 2023]
Blastocyst stage – an early development stage of an embryo. It forms an outer cell mass, which will give rise to the placenta, and an inner cell mass, from which the embryo itself will develop.
Source: Gilbert SF. Developmental Biology. 6th ed. Sunderland, USA: Sinauer Associates; 2000.
C
Capacitation - the preparation and activation of the sperm cells so that they can fertilize an egg cell. The environment of the vagina is very important for this.
Source: Alberts B, Johnson A, Lewis J, Raff M, Roberts K and Walter P. Molecular biology of the cell. 4th ed. Oxford University Press; 2003 and Gupta SK. Role of zona pellucida glycoproteins during fertilization in humans. Journal of Reproductive Immunology. 2015;108:90-7. DOI: 10.1016/j.jri.2014.08.006
Cell division - during the process of cell division, the chromosomes inside the cell are duplicated so that each daughter cell obtains a complete set of chromosomes after the whole process. With high maternal age, there is an increased amount of cell division errors, causing the chromosomes to be not properly divided among the two daughter cells. This can result in monosomy and trisomy.
Source: Alberts B, Johnson A, Lewis J et al. Molecular Biology of the Cell. 6th ed. New York: Garland Science; 2015.
Cell free (fetal) DNA – degraded DNA fragments shed into the bloodstream. Cell-free DNA (cfDNA) refers to different types of circulating DNA building blocks that are freely moving in the circulation, such as circulating tumor DNA, cell-free mitochondrial DNA (which is DNA from the energy-producing part of a cell) and cell-free fetal DNA (cffDNA) from the placenta during pregnancy.
Source: Gravina S, Sedivy JM, Vijg J. The dark side of circulating nucleic acids. Aging Cell. 2016 Jun;15(3):398-9. DOI: 10.1111/acel.12454.
Cervical mucus – these are secretions built up in the cervix to protect the vagina and the uterus from infection. Cervical mucus (slime) is also important for the motility (movement) of sperm cells, which is relevant when you’re trying to get pregnant. The mucus comes out of the vagina as part of vaginal discharge. Around your ovulation, it’s typically clear and runny, like egg whites.
Source: Curlin M, Bursac D. Cervical mucus: from biochemical structure to clinical implications. Front Biosci (Schol Ed). 2013;5(2):507-15. DOI: 10.2741/s386
Cervix - the lower, narrow part of the uterus (womb), connecting the uterus and the vagina. The cervix is also called the birth channel, because the baby exits the womb through this part.
Source: Paulsen F, Waschke J (eds.). Internal Organs. 16th ed. Munich, Germany: Elsevier; 2018.
Chorion - the outer membrane of the placenta. It’s well-vascularized by blood from the mother or pregnant person. The chorion is responsible for making sure the baby receives nutrients and oxygen. It also removes toxic substances and carbon dioxide (CO2) from the baby’s circulation.
Source: Source: Moore KL, Persaud TVN, Torchia MG. The Developing Human. 10th ed. Philadelphia, USA: Elsevier; 2016.
Chorionic villus sampling - an invasive prenatal test in which bits of tissue called villi are removed from the placenta (the chorion part), after which the sample is tested for abnormalities. Read more about invasive prenatal testing here.
Source: Jones TM, Montero FJ. Chorionic Villus Sampling. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2018.
Chromatid - during the process of cell division, your chromosomes are duplicated so that they can be distributed equally over two new cells that contain the exact same genetic information. Until then, the duplicated chromosomes stay attached to the original ones. Both the original chromosome and the duplicated chromosome in a pair are referred to as a chromatid while they are attached.
Source: Wadsworth P, Titus J. Mitosis. In: Lennarz WJ, Lane MD (eds). Encyclopedia of Biological Chemistry. 2nd ed. Philadelphia, USA: Elsevier; 2013. p. 181-184.
Chromosomal abnormalities - any structural or numerical abnormality of one or more chromosomes. This can involve aneuploidy, breakage of the chromosome, chromosomes having lost or exchanged big chunks, polyploidy (in which case a cell contains more than two copies of all chromosomes, for example four or eight copies of every chromosome) and more. These issues can happen in any chromosome, including the sex chromosomes. A person might be born with a chromosomal abnormality, which is referred to as a congenital abnormality. In this case, most of that person’s cells are typically affected. In other cases, a person develops the abnormality at some point in life. This is referred to as an acquired abnormality. In this case, only a small portion of a person’s cells are affected. What the effect of any given abnormality is, depends on which cells are affected, how many of them are affected, and in what way. This varies greatly between cases.
Source: Queremel Milani DA, Tadi P. Genetics, Chromosome Abnormalities. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022.
Chromosome - your entire genetic code is subdivided into several separate DNA molecules, each of which forms one chromosome by becoming very tightly wound and by associating with proteins that help form this dense shape. This saves a lot of space compared to if your DNA was floating in your cells stretched out (in which case it is about two meters or six feet) – and it makes organization within the cell nucleus (where the DNA is) much easier. Each of your cells contains 46 chromosomes arranged in pairs – you inherited one of the pair from your father and one from your mother. Most of your chromosomes (22 pairs) are autosomal chromosomes; the last pair are your sex chromosomes.
Source: Alberts B, Johnson A, Lewis J et al. Molecular Biology of the Cell. 4th ed. New York: Garland Science; 2002. and Queremel Milani DA, Tadi P. Genetics, Chromosome Abnormalities. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022.
Confined placental mosaicism (CPM) - chromosomal abnormalities that are only present in tissue from the placenta, and are not present anywhere in the fetus itself.
Source: Toutain J, Goutte-Gattat D, Horovitz J, Saura R. Confined placental mosaicism revisited: Impact on pregnancy characteristics and outcome. PLoS One. 2018;13(4):e0195905. DOI: 10.1371/journal.pone.0195905.
Corpus luteum - a temporary structure that is important for fertility. It’s made out of the cells of the dominant follicle after ovulation. It produces progesterone to keep the lining of the womb (the endometrium) intact. It is broken down if the egg from ovulation isn’t fertilized.
Source: Hoffman BL, Schorge JO, Halvorson LM, Hamid CA, Corton MM, Schaffer JI (eds.). Williams Gynecology. 4th ed. New York: McGraw-Hill Medical; 2020.
Cystic fibrosis – cystic fibrosis is a genetic disorder that is usually inherited. A mistake in the genetic code causes mucus (slime) to be more thick and sticky. It especially affects the lungs and the bowels. This causes affected people to have trouble breathing, diarrhea and recurring infections.
Source: Rafeeq MM, Murad HAS. Cystic fibrosis: current therapeutic targets and future approaches. Journal of Translational Medicine. 2017;15(1):84. DOI: 10.1186/s12967-017-1193-9
Cytology - the study of cells, typically using a microscope. The cytologist - a scientist doing cytology - looks at the structure of the cells to see if they're healthy. They can also look at how the cells respond to coloring them with a dye. Cytology can be used to diagnose a disease. Sometimes, it's used as a screening test, such as a Pap smear.
Source: Al-Abbadi MA. Basics of cytology. Avicenna Journal of Medicine. 2011;1(1):18-28. DOI: 10.4103/2231-0770.83719
D
Deferens duct – a tube that runs from the testicle to the urethra (the duct that transports urine from the bladder to outside the body). Both testicles have their own deferens duct. The deferens ducts are responsible for bringing sperm into the urethra when you’re sexually aroused. Along the way, several other ducts bring fluids and proteins into the mix to create semen, which is what comes out of the penis when you ejaculate.
Source: Marieb EN. Human Anatomy & Physiology. 5th ed. San Fransisco, USA: Benjamin Cummings; 2001.
Diploid - diploid cells have two sets of chromosomes. This means they contain the complete amount of DNA that is needed for most cells to work well. With the exception of gametes (reproductive cells such as sperm and egg cells), almost all cells in the human body are diploid.
Source: Li Y, Shuai L. A versatile genetic tool: haploid cells. Stem Cell Research & Therapy. 2017;8(1):197. DOI: 10.1186/s13287-017-0657-4
DNA (deoxyribonucleic acid) - the substance in each of our cells that contains our genetic code. Each DNA molecule consists of two long strands, which wind around each other to form a helix-shaped structure. Each strand is mainly composed of four different building blocks (adenine, guanine, cytosine, and thymine), which are called nucleotides. Specific sequences of these building blocks, or nucleotides, tell the cell’s machinery exactly which proteins should be produced. Differences in people’s DNA are due to different sequences of nucleotides – which leads to differences in people’s appearance or how their body functions.
Source: Alberts B, Johnson A, Lewis J et al. Molecular Biology of the Cell. 4th ed. New York: Garland Science; 2002.
E
Embryo - the correct medical term for the growing baby from conception up to and including week 8 (two months) of pregnancy.
Source: Moore KL, Persaud TVN, Torchia MG. The Developing Human. 11th ed. Philadelphia, USA: Elsevier; 2020.
Endocrine tissue - tissue that is responsible for the production and release of hormones. For example, the ovaries are an endocrine tissue, because they produce estrogen and progesterone. Lots of other tissues are endocrine tissue as well, including parts of the brain, the pancreas and liver, and fat tissue.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Endometrial - relating to the endometrium. For example, "endometrial cells" are cells from the endometrium.
Endometriosis - a chronic condition in which tissue similar to the lining of the uterus grows outside the uterus. This misplaced tissue can be found on organs in the pelvic region, such as the ovaries, fallopian tubes, and the lining of the pelvis. It responds to hormonal changes during the menstrual cycle, leading to inflammation, pain, and the formation of scar tissue. Endometriosis is a common cause of pelvic pain and can also result in fertility problems. You can read more about the disease here.
Source: Czyzyk A, Podfigurna A, Szeliga A, Meczekalski B. Update on endometriosis pathogenesis. Minerva Ginecol. 2017;69(5):447-461. DOI: 10.23736/S0026-4784.17.04048-5
Endometrium – the mucous cell layer that lines the uterus. It thickens throughout the menstrual cycle in preparation for embryo implantation, and is shed during menstruation.
Source: Marieb EN. Human Anatomy & Physiology. 5th ed. San Fransisco, USA: Benjamin Cummings; 2001.
Enzyme - enzymes are a special class of proteins that are needed to speed up chemical reactions within living beings. By binding to specific molecules, enzymes can modify them in ways that make it easier to alter their shape, break them apart, or combine them with other molecules.
Source: Dixon M, Webb EC. Enzymes. 1st ed. New York, USA: Academic press; 1960.
Epithelium - the epithelium is a layer of tissue (a group of cells) that covers organs and other structures in the body. For example, your skin is built mainly from epithelium. It’s also found on the inside of lots of organs, including your mouth, throat, lungs and bowels, and sex organs such as the vagina and penis. It can be composed of different cell types, including squamous cells or column-shaped cells.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Estrogen - steroid hormone that is important for the regulation of the female reproductive organs (the ovaries and uterus). It comes in different forms. During the years that you’re fertile (your reproductive years), estradiol is the most common type of estrogen. Estrogen is also present in biological males. It plays a role in how sperm cells mature.
Source: Hoffman BL, Schorge JO, Halvorson LM, Hamid CA, Corton MM, Schaffer JI (eds.). Williams Gynecology. 4th ed. New York: McGraw-Hill Medical; 2020.
Extravillous trophoblast cells - special cells that develop from the placenta, that cause alterations in the structure of certain blood vessels in the uterus.
Source: Moore KL, Persaud TVN, Torchia MG. The Developing Human. 11th ed. Philadelphia, USA: Elsevier; 2020.
F
Fallopian tube - either of two tubes along which the eggs, produced by the ovaries, travel towards the uterus.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Fetus - the correct medical term for the growing baby from the start of week 9 of pregnancy until birth.
Source: Moore KL, Persaud TVN, Torchia MG. The Developing Human. 11th ed. Philadelphia, USA: Elsevier; 2020.
Fibroid - fibroids are non-cancerous (benign) growths that develop in or on the uterus. They are composed of muscle and fibrous tissue. Symptoms may include heavy menstrual bleeding, pelvic pain, and fertility issues, though many people who have them don’t ever have symptoms from them. Treatment options vary depending on symptoms and can include medication or surgery.
Source: Zepiridis LI, Grimbizis GF, Tarlatzis BC. Infertility and uterine fibroids. Best Pract Res Clin Obstet Gynaecol. 2016;34:66-73. DOI: 10.1016/j.bpobgyn.2015.12.001
Follicles – most people who can become pregnant have 300,000 to 400,000 small fluid filled sacs inside their ovaries, containing immature egg cells. A follicle also contains nutrients to support an egg cell's growth and maturation. During a typical menstrual cycle, one follicle releases one mature egg cell, which can then be fertilized.
Source: McGee EA, Hsueh AJW. Initial and Cyclic Recruitment of Ovarian Follicles. Endocrine Reviews. 2000;21(2):200-214. DOI: 10.1210/edrv.21.2.0394
FSH (Follicle stimulating hormone) - a hormone that stimulates the maturation of egg cells and sperm cells. It stimulates follicles in the ovaries to grow and the eggs inside them to mature. This hormone is produced in the pituitary gland in the brain.
Source: Orlowksi M, Sarao MS. Physiology, Follicle Stimulating Hormone. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022
G
Gamete - gametes are the female and male reproductive cells. Most men have sperm cells and most women have egg cells (also known as ova or oocytes).
Source: Alberts B, Johnson A, Lewis J, Raff M, Roberts K and Walter P. Molecular biology of the cell. 4th ed. Oxford University Press; 2003
Gene - genes are segments of DNA that contain the instructions for the body's building blocks. Eye color, skin color and hair texture are all determined by genes, for example. Some traits are determined by a single gene, but most traits are determined by multiple genes working together.
Source: Alberts B, Johnson A, Lewis J, Raff M, Roberts K and Walter P. Molecular biology of the cell. 4th ed. Oxford University Press; 2003
Genetic disorders – genetic disorders are diseases caused by a change in the genetic code of a person. The issue can be in a single gene (monogenic disease), multiple genes, or in your chromosomes. Many are inherited (from your parents). Some are created by chance during fertilization (when you were made).
Source: National Human Genome Research Institute. Genetic Disorders. https://www.genome.gov/For-Patients-and-Families/Genetic-Disorders
Gestation - the age of a fetus counted from the first day of your last menstrual period. See also Gestational age.
Source: Moore KL, Persaud TVN, Torchia MG. The Developing Human. 11th ed. Philadelphia, USA: Elsevier; 2020.
Gestational age – this is the current age of a fetus (baby inside the womb) as measured from the start of your last menstrual period. This age is expressed in weeks and days.
The gestational age is different from the age of conception. This is because conception, which is when the egg cell and sperm cell meet to create a pregnancy, happens around ovulation. Ovulation takes place about two weeks after the start of a menstrual period. The gestational age is therefore two weeks older than the real age of the fetus. However, it’s quite difficult to determine when ovulation takes place within your cycle; it commonly varies a bit between cycles. People do often remember when their last period started. That’s why gestational age is a more common measure of the age of a fetus. But, it’s not a perfect method. In the first and sometimes second trimester, it’s standard in most places to measure gestational age using ultrasound. The sizes of different structures within the fetus are measured, which approximately indicates how old the fetus is.
Source: Mongelli M. Evaluation of Gestation. In: Ramus RM (ed). Medscape. 2021.
Gestational diabetes - this is a form of diabetes that can develop during pregnancy (gestation). Typically, it disappears again after pregnancy. You can read more about it here. In short, it is caused by insulin resistance. Insulin is a hormone that controls your blood sugar levels. When you’re resistant to insulin, your cells can’t take up sugar as easily. Your cells need sugar for energy. The sugar stays in your blood instead, which is toxic for your blood vessels. This condition can increase the risk of complications for a pregnant person and their baby. Some factors give you a higher risk of gestational diabetes. These factors include obesity, a family history of the disorder, and being a bit older when you’re pregnant.
Source: Alfadhli EM. Gestational diabetes mellitus. Saudi Medical Journal. 2015;36(4):399-406. DOI: 10.15537/smj.2015.4.10307
Glandular cells - elongated cells that produce mucus (slime). They form an important part of the lining of many organs. For example, the lining of the bowels.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Gonads - the gonads are the primary reproductive organs. In a person of the biological female sex, these are the ovaries. In a person of the biological male sex, these are the testicles.
Source: Kuiri-Hänninen T, Sankilampi U, Dunkel L. Activation of the hypothalamic-pituitary-gonadal axis in infancy: minipuberty. Hormone Research in Paediatrics. 2014;82(2):73-80. DOI: 10.1159/000362414 and Seppä S, Kuiri-Hänninen T, Holopainen E, Voutilainen R. MANAGEMENT OF ENDOCRINE DISEASE: Diagnosis and management of primary amenorrhea and female delayed puberty. European Journal of Endocrinology. 2021;184(6):R225-R242. DOI: 10.1530/EJE-20-1487
H
Haploid - haploid cells have a single set of chromosomes. This means that they contain half the amount of DNA compared to diploid cells. Examples of haploid cells include sperm cells and egg cells (also known as gametes). These cells are needed for reproduction, because only they can combine their DNA during fertilization. This leads to a single cell called a zygote. The zygote contains two full sets of chromosomes. The zygote can then grow into an embryo and, later, a baby.
Source: Li Y, Shuai L. A versatile genetic tool: haploid cells. Stem Cell Research & Therapy. 2017;8(1):197. DOI: 10.1186/s13287-017-0657-4
Hormone - a molecule used by a body cell to send signals to other, far-away cells via the bloodstream. Hormones exist in different varieties. For example, estrogen and testosterone are fatty hormones made from cholesterol. Those are called steroid hormones. Other hormones, such as adrenaline, are made from the building blocks of proteins (called amino acids). Different hormones can have different effects on different cells, or even on the same cell under different circumstances.
Source: Alberts B, Johnson A, Lewis J et al. Molecular Biology of the Cell. 6th ed. New York: Garland Science; 2015 and Molnar C, Gair J. Concepts of Biology – 1st Canadian Edition. BCcampus; 2015. Available from: https://opentextbc.ca/biology/
Hypertension - hypertension, also known as high blood pressure, is a medical condition in which the force of blood against your arteries’ walls is consistently too high. This puts extra strain on the heart and blood vessels. It can increase the risk of heart disease, stroke, and other health problems.
Source: Oparil S, Acelajado MC, Bakris GL, Berlowitz DR, Cífková R, Dominiczak AF, et al. Hypertension. Nature Reviews Disease Primers. 2018;4:18014. DOI: 10.1038/nrdp.2018.14
Hypothalamus - the hypothalamus is a complex structure in the brain. Among several other functions, it produces hormones that are important for the control and development of the reproductive tract.
Source: Everitt BJ, Hökfelt T. Neuroendocrine anatomy of the hypothalamus. Acta Neurochirurgica Supplementum (Wien). 1990;47:1-15. DOI: 10.1007/978-3-7091-9062-3_1 and Seppä S, Kuiri-Hänninen T, Holopainen E, Voutilainen R. MANAGEMENT OF ENDOCRINE DISEASE: Diagnosis and management of primary amenorrhea and female delayed puberty. European Journal of Endocrinology. 2021;184(6):R225-R242. DOI: 10.1530/EJE-20-1487
Hysteroscopy – during a hysteroscopy, a doctor inserts a very small camera into the uterus through the cervix. This way, they can see inside the uterus to diagnose and sometimes treat diseases or growths. Some examples of issues a hysteroscopy could be useful for include abnormal bleeding, polyps, fibroids, adhesions (tissue sticking together), and fertility problems.
Source: Salazar CA, Isaacson KB. Office Operative Hysteroscopy: An Update. J Minim Invasive Gynecol. 2018;25(2):199-208. DOI: 10.1016/j.jmig.2017.08.009
I
Immune system - this is the complex of interactions and responses that your body uses to defend itself against pathogens. Your body produces special cells (white blood cells) that fight off these pathogens. Some of these cells (B cells) produce antibodies that recognize antigens that come from these pathogens. That way, your body knows there’s an intruder somewhere.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Inflammation - the immune system creates inflammation by doing its job. The cells of the immune system produce all sorts of molecules that are important for healing. But this also often leads to redness, pain, and warm-feeling skin in the affected area. Inflammation is different from infection. When you have an infection, there is a microbe that has invaded your body. Your immune system responds to this invader by producing inflammation. But your body can also trigger the immune system to produce inflammation if there's no invader. For example, surgery or breaking a bone lead to inflammation because your body needs to heal. This is normal.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Intraepithelial - “intra” means inside. So, an intra-epithelial structure can be found inside the epithelium.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
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L
Luteal phase – describes one of the phases of the menstrual cycle, after ovulation but before menstruation. During this phase, the lining of your uterus typically thickens in anticipation of a potential pregnancy. This lining is then shed during menstruation.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Luteinizing hormone – a hormone in the human body, which triggers ovulation when present in high levels, and is important to keep an early pregnancy viable (meaning it prevents menstruation). Often abbreviated as LH.
Source: Marieb EN. Human Anatomy & Physiology. 5th ed. San Fransisco, USA: Benjamin Cummings; 2001.
M
Meiosis – a type of cell division that takes place in sex cells (egg cells and sperm cells), which reduces the number of chromosomes in the resulting cells to half the normal number (23 instead of 46 chromosomes). This is different from mitosis. That is the regular type of cell division in which the resulting cells have the same number of chromosomes as the original cell. The reason why sex cells use meiosis, is because an egg cell and a sperm cell are meant to combine into one cell at fertilization. That means they can’t have a full set of chromosomes each, because the resulting cell (from which an embryo develops) would have two sets of chromosomes (92 instead of 46).
Source: Alberts B, Johnson A, Lewis J et al. Molecular Biology of the Cell. 4th ed. New York: Garland Science; 2002.
Membrane - layer of cells that often separates different types of tissue or different cavities in the body. Examples include: the chorion and amnion (membranes of the placenta), the lining of your gut, and the pleura (a membrane that holds your lung tissue). Your skin is also a membrane.
Note: “membrane” in biology can also refer to, for example, the outer layer of a single cell (the cell membrane).
Source: Merriam-Webster. “membrane”. 2023. https://www.merriam-webster.com/dictionary/membrane [Accessed June 24th, 2023] and Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Menarche - the menarche is the first menstrual period (menstrual bleeding) of a person with female reproductive organs. It is considered to be a late sign of puberty.
Source: Karapanou O, Papadimitriou A. Determinants of menarche. Reproductive Biology and Endocrinology. 2010;8:115. DOI: 10.1186/1477-7827-8-115 and Seppä S, Kuiri-Hänninen T, Holopainen E, Voutilainen R. MANAGEMENT OF ENDOCRINE DISEASE: Diagnosis and management of primary amenorrhea and female delayed puberty. European Journal of Endocrinology. 2021;184(6):R225-R242. DOI: 10.1530/EJE-20-1487
Menses - menses is another word for menstruation. It refers to the regular outflow of blood and tissue from the inner lining of the uterus (the endometrium) through the vagina.
Source: Critchley HOD, Maybin JA, Armstrong GM, Williams ARW. Physiology of the Endometrium and Regulation of Menstruation. Physiological Reviews. 2020;100(3):1149-1179. DOI: 10.1152/physrev.00031.2019
Microbe/pathogen - microbes are living organisms that cannot be seen with our eyes. Microbes include bacteria, viruses and also fungi. While some microbes can make humans sick (then referred to as a pathogen), others are very important for us humans and are in our digestive system, breathing system and on our skin.
Source: American Museum of Natural History. Microbes A-Z: Your Questions answered. Available from: https://www.amnh.org/explore/microbe-facts [Accessed November 30th, 2022]
Monogenic diseases – these are rare diseases that are caused by an error in a single gene, such as cystic fibrosis. This is in contrast to polygenic diseases (most genetic diseases), which involve multiple genes. Monogenic diseases sometimes run in the family, because they can be transferred directly from parent to child when egg and sperm cells are made.
Source: Prakash V, Moore M, Yáñez-Muñoz RJ. Current Progress in Therapeutic Gene Editing for Monogenic Diseases. Mol Ther. 2016;24(3):465-74. DOI: 10.1038/mt.2016.5
Müllerian ducts - in an embryo, the Müllerian ducts are present in both sexes at first. Later, they are broken down under the influence of Anti-Mullerian Hormone (AMH). This hormone is produced by the testicles of the embryo. This stops the development of female reproductive organs in embryos that are biologically male. Without AMH, the ducts develop into the uterus, fallopian tubes, cervix, and the upper third of the vagina.
Source: Wilson D, Bordoni B. Embryology, Mullerian Ducts (Paramesonephric Ducts). In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022
Multiple sclerosis – multiple sclerosis (MS) is an autoimmune disease that damages the protective covering of nerve fibers in the central nervous system (brain and spinal cord). This leads to neurological symptoms such as weakness, numbness, balance problems, and cognitive (thinking) difficulties.
Source: Dobson R, Giovannoni G. Multiple sclerosis - a review. European Journal of Neurology. 2019;26(1):27-40. DOI: 10.1111/ene.13819
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NIPT - NIPT stands for non-invasive prenatal testing. It is a blood test that can be done during pregnancy to test for chromosomal abnormalities without the risk of harm to the baby. The test relies on DNA released from cells in the placenta, which are identical to the baby’s cells in most cases, into the pregnant person’s blood. Read more about NIPT here.
Source: Goldwaser T, Klugman S. Cell-free DNA for the detection of fetal aneuploidy. Fertility and Sterility. 2018;109(2):195-200. DOI: 10.1016/j.fertnstert.2017.12.019
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Ova - plural of ovum; multiple egg cells
Ovaries - the ovaries are organs inside the pelvic cavity of most people with a female reproductive system. Typically, there is one on each side of the uterus. Each is connected to the uterus via a fallopian tube. The ovaries only produce eggs when you’re still a fetus in the womb – which means you’ll have all the eggs you’ll ever have by the time you’re born. These eggs then mature in your ovaries as you age. The ovaries also produce hormones such as estrogen and progesterone, which influence what your body looks like and how it functions.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Ovulation - the process in which a mature egg cell is released from its follicle, under the influence of luteinizing hormone.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Ovum - an ovum, also known as an egg cell, is a female reproductive cell. This cell is required for reproduction (making a baby). It is released by one of the ovaries every month during ovulation.
Source: Holesh JE, Bass AN, Lord M. Physiology, Ovulation. In: StatPearls. StatPearls Publishing, Treasure Island (FL); 2022.
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Pathogen - see Microbe
Pelvis and pelvic wall - the pelvis is the part of the body located between the hips and below the abdomen (belly). It holds the pelvic organs, such as the bladder, the rectum, the ovaries and uterus (in most women), and the prostate (in most men). The walls of the pelvis are composed of muscle and supportive tissue. The pelvic floor is especially important, because it plays a role in continence (being able to hold your pee and poop).
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Pituitary gland - an important gland in the brain that produces hormones. The gland consists of two parts (lobes): an anterior (front) lobe and a posterior (back) lobe.
The anterior pituitary makes lots of different hormones in response to signals from the hypothalamus (another important gland in the brain). These hormones are then secreted into the blood. For example, it produces LH and FSH, which are important hormones for the reproductive system in all sexes. It also makes growth hormone, which stimulates the production of proteins in cells.
The posterior pituitary is also connected to the hypothalamus. Instead of making hormones itself, it stores hormones made by the hypothalamus and releases them when necessary. This only concerns two main hormones: oxytocin (which is important for bonding between people, for childbirth and for breastfeeding) and antidiuretic hormone (which reduces how much you pee).
Source: Ilahi S, Ilahi TB. Anatomy, Adenohypophysis (Pars Anterior, Anterior Pituitary). In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022 and Patel H, Jessu R, Tiwari V. Physiology, Posterior Pituitary. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022
Placenta - the placenta develops between the amniotic sac that holds the baby, and the lining of the uterus. It contains blood vessels that bring nutrients and oxygen to the baby from the circulation of the baby’s carrier and that remove waste from the baby’s circulation. The placenta is typically also delivered by the pregnant person, after delivery of the baby.
Source: Moore KL, Persaud TVN, Torchia MG. The Developing Human. 11th ed. Philadelphia, USA: Elsevier; 2020.
Placenta disorders – describe a number of conditions which relate to diseases, disorders or dysfunction of the placenta during pregnancy. These can lead to pre-eclampsia, preterm delivery, premature rupture of membranes, or placental abruption (in which the placenta separates from the wall of the uterus before birth). Unfortunately, there is no treatment option to date – typically, the baby should be delivered soon.
Source: Parker SE, Werler MM. Epidemiology of ischemic placental disease: a focus on preterm gestations. Semin Perinatol. 2014;38(3):133-138. DOI: 10.1053/j.semperi.2014.03.004. and Kosińska-Kaczyńska K. Placental Syndromes—A New Paradigm in Perinatology. International Journal of Environmental Research and Public Health. 2022; 19(12):7392. DOI: 10.3390/ijerph19127392
Polyps - polyps are abnormal growths that can occur in different parts of the body, including the uterus. In the uterus, they are small, benign growths in the lining (endometrium). They can cause irregular bleeding or fertility issues. Usually, they’re removed through minimally invasive procedures (small surgeries).
Source: Salim S, Won H, Nesbitt-Hawes E, Campbell N, Abbott J. Diagnosis and management of endometrial polyps: a critical review of the literature. J Minim Invasive Gynecol. 2011;18(5):569-81. DOi: 10.1016/j.jmig.2011.05.018
Pre-implantation Genetic Testing (PGT) – the genetic testing and examination of fertilized cells before they are implanted back into the uterus to avoid birth defects of the future child. This is used in assisted reproductive technologies (ART), which you can read more about here.
Source: Sullivan-Pyke C, Dokras A. Preimplantation Genetic Screening and Preimplantation Genetic Diagnosis. Obstetrics and Gynecology Clinics of North America. 2018;45(1):113–125. DOI:10.1016/j.ogc.2017.10.009.
Pre-term labor or pre-term birth - pre-term labor means you’re giving birth before 37 weeks of pregnancy (gestation). Because some organs are still immature, babies who are delivered pre-term are more likely to have a low birth weight, for example. Their lungs might be underdeveloped, which is a risk for respiratory distress syndrome. Pre-term labor can happen for different reasons. Illnesses like infections (chorioamnionitis, for example) can lead to pre-term labor. Twin pregnancies are also more likely to cause pre-term labor.
Source: Romero R, Dey SK, Fisher SJ. Preterm labor: one syndrome, many causes. Science. 2014;345(6198):760-765. DOI: 10.1126/science.1251816 and World Health Organization. Preterm birth. https://www.who.int/news-room/fact-sheets/detail/preterm-birth [Accessed June 24th, 2023]
Progesterone - progesterone is a hormone that is produced naturally by the body. It is important during pregnancy, to make sure the environment in the womb is fit for the embryo. It’s also important in some other body functions, including for the production of sperm cells.
Source: Edwards M, Can AS. Progestin. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022 and Cable JK, Grider MH. Physiology, Progesterone. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022.
Progestin – a progestin is a synthetic (which means made by humans) version of progesterone. Progestins come in different forms, and are used to treat a variety of medical conditions. One important use of progestins is for contraception (birth control), because taking a progestin makes the mucus in the cervix thicker (which makes it hard for sperm cells to swim through), makes the endometrium thinner (which makes implantation of a fertilized egg harder), and suppresses the release of other hormones that lead to ovulation.
Source: Edwards M, Can AS. Progestin. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022 and Cable JK, Grider MH. Physiology, Progesterone. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022.
Prolactin – prolactin is a hormone responsible many things in the male and female body. It is mostly known to be responsible for breast development and making milk during breastfeeding. But it has many more functions in, for example, the brain and the immune system. Additionally, high prolactin levels (hyperprolactinemia) in males are considered to be a cause of male infertility.
Sources: Freeman ME, Kanyicska B, Lerant A, Nagy G. Prolactin: Structure, Function, and Regulation of Secretion. Physiological Reviews. 2000;80(4):1523-631. DOI: 10.1152/physrev.2000.80.4.1523 and Dabbous Z, Atkin SL. Hyperprolactinaemia in male infertility: Clinical case scenarios. Arab Journal of Urology. 2018;16(1):44-52. DOI: 10.1016/j.aju.2017.10.002
Prolapse – a prolapse is when an organ in the pelvic cavity (typically the uterus, the bladder, or the rectum) isn’t held in place properly by the surrounding structures (mostly the muscles of the pelvic floor). It can then come down into the vagina or even outside it. The rectum can also come down into the anus or outside it. A prolapse can be quite uncomfortable, but can be managed through a variety of surgical and non-surgical treatments.
Source: Hacker NF, Gambone JC, Hobel CJ (eds.). Hacker & Moore’s Essentials of Obstetrics & Gynecology. 6th ed. Philadelphia: Elsevier; 2016.
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Respiratory distress syndrome - a disease in which the lungs do not have enough capacity to supply the organs in the human body with enough oxygen. This occurs mainly in babies that were born prematurely, because their lungs are underdeveloped.
Source: Pramanik AK. Respiratory Distress Syndrome. In: Rosenkrantz T (ed.). Medscape. 2020. Available from: https://emedicine.medscape.com/article/976034-overview#a4 [Accessed September 3rd, 2022]
Rhesus - the rhesus factor is a small protein (an antigen) on the surface of red blood cells. It can be present in several variations, but the most important variation in the context of pregnancy is the rhesus D factor, also written as Rh(D). If you have the Rh(D) antigen, you’re said to have a positive blood type. If you don’t, you have a negative blood type. This is indicated by adding a plus or a minus to the blood type. For example, if you have blood type A and you have the Rh(D) factor, you’re said to have blood type A+ (pronounced “A-positive”). Normally, it doesn’t matter whether you do or don’t have this Rh(D) factor. However, if you have a negative blood type and you’re pregnant with a baby that has a positive blood type, your body starts making antibodies against the Rh(D) factor. This is typically not a problem for your first pregnancy with an Rh(D)-positive baby. When you’re pregnant with a second Rh(D)-positive baby, your antibodies can start to attack that baby’s blood cells, which can make them very sick.
Source: Source: Costumbrado J, Mansour T, Ghassemzadeh S. Rh Incompatibility. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2022.
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Scrotum – the scrotum is the external pouch of skin that contains and protects the testicles.
Source: Older RA, Watson LR. Ultrasound anatomy of the normal male reproductive tract. Journal of Clinical Ultrasound. 1996;24(8):389-404. DOI: 10.1002/(SICI)1097-0096(199610)24:8<389::AID-JCU1>3.0.CO;2-G
Semen – the fluid that comes out of the penis during ejaculation. It usually contains sperm cells and fluid that’s produced by different organs in the reproductive tract. Those organs include the prostate and the so-called seminal vesicles, which are beneath the bladder and produce most of the fluid. The bulbourethral glands also produce fluid for semen, and they are at the base of the penis. All these organs are connected to the deferens duct (sperm tube) or, from the bladder on, to the urethra (urine tube). The fluids produced by these organs contain hormones, proteins and lots of nutrients for the sperm cells. If you’ve had a vasectomy (sterilization for people with testicles), your semen doesn’t contain sperm cells, only fluids.
Source: Mason MM, Schuppe K, Weber A, Gurayah A, Muthigi A, Ramasamy R. Ejaculation: the Process and Characteristics From Start to Finish. Current Sexual Health Reports. 2023;15(1):1-9. DOI: 10.1007/s11930-022-00340-z
Sensitivity – sensitivity and specificity are measures of accuracy of a test. Sensitivity measures how many cases of disease a test can detect, out of all the people who actually have the disease who undergo the test. A test with high sensitivity can detect many or nearly all cases of disease (the so-called “true-positive” results, which are those cases in which the test indicates there is disease and there actually is) and only misses a few (the so-called “false-negative” results, which are those cases in which the test indicates there is no disease when there actually is disease). Therefore, highly sensitive tests have a high rate of true positives and a low rate of false negatives. This allows a physician to exclude disease based on a negative test result: if the test says there is no disease, this is highly likely to be true, because the test is so good at detecting when you’re sick. A test with (very) high sensitivity commonly has lower specificity, because it’s difficult for a test to be very good at detecting both sick and healthy people.
Source: Parikh R, Mathai A, Parikh S, Chandra Sekhar G, Thomas R. Understanding and using sensitivity, specificity and predictive values. Indian J Ophthalmol. 2008;56(1):45-50. DOI: 10.4103/0301-4738.37595
Sex chromosomes - the pair of chromosomes that determines your biological sex (usually XX for female and XY for male, but other variations can occur).
Source: Alberts B, Johnson A, Lewis J et al. Molecular Biology of the Cell. 6th ed. New York: Garland Science; 2015.
Sequencing (DNA) - any technique used to determine the sequence of nucleotides in DNA (your genetic code) obtained from a sample of your blood or tissue. This allows the scientist performing the technique to detect abnormalities in your genes, which could be the cause of disease. If your whole genetic code (genome) is looked at, it’s called “whole genome sequencing”.
Source: Heather JM, Chain B. The sequence of sequencers: The history of sequencing DNA. Genomics. 2016;107(1):1-8. DOI: 10.1016/j.ygeno.2015.11.003
Screening - a method of testing for disease or abnormalities that is designed to detect as many cases of this disease or abnormality as possible. However, because of this, screenings will commonly give a positive result (that is, indicate that a person has the disease) even when a person does not have the disease. This is called a false-positive result. This characteristic makes screenings unsuitable for confirming a diagnosis, but they are a great tool for deciding who needs further, often more intensive or invasive testing. In other words, screenings indicate an increased risk of a disease or abnormality, not a definitive diagnosis.
Source: Maxim LD, Niebo R, Utell MJ. Screening tests: a review with examples. Inhalation Toxicology. 2014;26(13):811-828. DOI: 10.3109/08958378.2014.955932
Specificity - sensitivity and specificity are measures of accuracy of a test. Specificity measures how many healthy people a test can detect, out of all the people who are actually healthy who undergo the test. A test with high specificity can detect many or nearly all healthy people (the so-called “true-negative” results, which are those cases in which the test indicates there is no disease and there actually isn’t) and only misses a few (the so-called “false-positive” results, which are those cases in which the test indicates there is disease when there actually isn’t). Therefore, highly specific tests have a high rate of true negatives and a low rate of false positives. This allows a physician to confirm disease based on a positive test result: if the test says there is disease, this is highly likely to be true, because the test is so good at detecting when you’re healthy. A test with (very) high specificity commonly has low sensitivity, because it’s difficult for a test to be very good at detecting both sick and healthy people.
Source: Parikh R, Mathai A, Parikh S, Chandra Sekhar G, Thomas R. Understanding and using sensitivity, specificity and predictive values. Indian J Ophthalmol. 2008;56(1):45-50. DOI: 10.4103/0301-4738.37595
Speculum – the speculum is a metal or plastic device that looks a bit like a duck’s beak, with two wide, blunt blades. It’s used to look at your cervix and walls of your vagina. To do so, your doctor will insert the speculum into the vagina and open the blades to catch the cervix in between these blades. This shouldn’t hurt, but can give some uncomfortable pressure. Speculums come in different sizes, and your doctor will choose one that fits based on whether you’ve had children and your body weight.
Source: Hacker NF, Gambone JC, Hobel CJ (eds.). Hacker & Moore’s Essentials of Obstetrics & Gynecology. 6th ed. Philadelphia: Elsevier; 2016.
Squamous cells - cells arranged like fish scales. They are found in the lining of organs, especially organs that are open to the outside of the body. Examples include the lining of the vagina and the mouth.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Steroid hormones - a group of hormones that are important for many processes in the body. They are made from a fatty substance called cholesterol. The group includes progesterone, estrogen and testosterone. See also: Hormones.
Source: Norman AW, Henry HL. Chapter 2 - Steroid Hormones: Chemistry, Biosynthesis, and Metabolism. In: Norman AW, Henry HL (eds.). Hormones. 3rd ed. San Diego: Academic Press; 2015. p. 27-53.
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Testosterone – testosterone is a steroid hormone that is important for the development of sex characteristics, producing sperm cells, and fertility. It’s the main sex hormone in males, but testosterone also plays an important in female reproductive and non-reproductive health.
Sources: Nassar GN, Leslie SW. Physiology, Testosterone. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2023 and Islam RM, Bell RJ, Green S, Davis SR. Effects of testosterone therapy for women: a systematic review and meta-analysis protocol. Systematic Reviews. 2019;8(1):19. DOI: 10.1186/s13643-019-0941-8
Thrombosis – describes a condition in which blood forms clots and blocks blood vessels. Typical symptoms include pain, swelling, redness, warmth, and numbness in the affected area, commonly the legs. This can happen under all sorts of circumstances, and is also more common in pregnancy. It is important that you contact a medical professional immediately when experiencing these symptoms, because complications of thrombosis can be life-threatening (including difficulty breathing and stroke).
Source: Marieb EN. Human Anatomy & Physiology. 5th ed. San Fransisco, USA: Benjamin Cummings; 2001.
Thyroid - the thyroid is a gland in the neck located beneath the voice box. It produces hormones and is involved in the regulation of growth and metabolism.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Thyroid-stimulating hormone (TSH) - a hormone produced by the pituitary gland in that brain, that regulates the function of the thyroid gland. It stimulates the production of thyroid hormones, which are essential for metabolism and growth.
Source: Babić Leko M, Gunjača I, Pleić N, Zemunik T. Environmental Factors Affecting Thyroid-Stimulating Hormone and Thyroid Hormone Levels. Int J Mol Sci. 2021;22(12):6521. DOI: 10.3390/ijms22126521
Tissue - in your body, cells are organized in specific ways. Similar cells are often grouped together, so that they can work together on some function. This collection of cells (and supportive material in between the cells) is called tissue. Humans have different tissue types: muscle tissue, nervous tissue, epithelial tissue (forming the skin and the lining of structures inside the body, such as the lungs and the bowels) and connective tissue (which support and connect structures in the body).
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
Trimester - a period of around three months, approximately one-third of a normal pregnancy. The first trimester is up to 12 weeks of pregnancy. The second trimester runs from 12 to 27 weeks. The third trimester runs from 28 to 40 weeks. Some authorities go by slightly different week cut-offs.
Source: Moore KL, Persaud TVN, Torchia MG. The Developing Human. 11th ed. Philadelphia, USA: Elsevier; 2020.
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Ultrasound analysis - an examination that uses sound waves and accompanying echoes to visualize the body’s internal structures. A cold-feeling gel is put on the skin beforehand, which helps direct the sound waves and optimizes picture quality.
Source: Morgan MA, Bell DJ. Ultrasound (introduction). Available from: https://radiopaedia.org/articles/32088 [Accessed September 3rd, 2022]
Uterus - an organ in the pelvic cavity of most people with a female reproductive system. This organ is connected to the vagina via its lowest and narrowest portion: the cervix. The uterus has a strong, muscular wall lined on the inside by thinner, slippery layers of cells (the endometrium). Most of the endometrium is shed during menstruation, and is built back up afterwards. The endometrium is also the layer in which a fertilized egg implants after about a week of pregnancy. During pregnancy, the fetus grows inside a fluid-filled sac (the amniotic sac) inside the uterus. The muscular wall of the uterus contracts during menstruation, which can be felt as cramping, and causes the contractions you feel during labor.
Source: Marieb EN, Hoehn K. Human Anatomy & Physiology. 10th ed. Essex, UK: Pearson Education Limited; 2016.
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Varicocele - enlargement of veins in the scrotum, which can lead to infertility.
Source: Fainberg J, Kashanian JA. Recent advances in understanding and managing male infertility. F1000 Research. 2019;8:670. DOI: 10.12688/f1000research.17076.1.
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Wilson’s disease – this is a rare disease in which your body can't get rid of copper due to a genetic defect. As a result, copper starts to build up in the body. This can lead to liver damage and neurological problems. If it’s not recognized in time, the disease can be fatal.
Source: Chaudhry HS, Anilkumar AC. Wilson Disease. In: StatPearls. Treasure Island, USA: StatPearls Publishing; 2018.
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Z
Zona pellucida - the zona pellucida is a protective layer that surrounds an ovum (egg cell). It is composed of specialized proteins that can recognize sperm cells that are ready for fertilizing. It only lets a single sperm cell through to fertilize the egg. That’s why it’s a very important part in the process of fertilization.
Source: Green DP. Three-dimensional structure of the zona pellucida. Reviews of Reproduction. 1997;2:147-56. DOI: 10.1530/revreprod/2.3.147
Zygote - the first cell of an embryo resulting from the fusion of a sperm cell and an egg cell (fertilization).
Source: Alberts B, Johnson A, Lewis J, Raff M, Roberts K and Walter P. Molecular biology of the cell. 4th ed. Oxford University Press; 2003