Category: medicine

Immunology 101: Stages of B-cell Development [Biology, MCAT, USMLE Medicine]

B-Cell Development Stages. stem cell –> early pro-B cell –> late pro-B cell –> large pre-B cell –> [1st checkpoint – selects for functional heavy chains] –> small pre-B cell –> [2nd checkpoint – select for functional light chains] –> Immature B cell (has surface IgM, no surface IgD). Somatic recombination is the process in which different individual gene segments of the H (heavy) chain combine with rearranged gene segments of the L (light) chain. The enzymes responsible for somatic recombination are the recombinase enzymes (RAG-1 and RAG-2) that recognize specific sequences (RSS) or recombination signal sequences. RAG-1 and RAG-2 are only expressed in B or T lymphocytes. These specific sequences recognized by the RAG-1 or RAG-2 enzymes are either a 1) heptamer or 2) nonamer. The heptamer literally contains 7 nucleotides, and the nonamer literally contains 9 nucleotides. There are typically 12 or 23 nucleotides in between the heptamer and nonamer to separate them.

Gastrointestinal System: Pathophysiology of Diseases and Cancers [Biology, MCAT, USMLE]

In this quick and easy guide, learn about Gastrointestinal System: Pathophysiology of Diseases and Cancers [Biology, MCAT, USMLE]. Topics include heptobiliary disease, understanding liver functions and cirrhosis, liver function tests, causes of liver injury, alcoholic hepatitis, NAFLD, NASH, viral hepatitis, autoimmune hepatitis, durg-induced liver injury, hereditary hemochromatosis, Wilson’s disease, Alpha-1 Antitrypsin Deficiency, PSC, PBC, cholelithiasis, cholecystitis, cholangitis, hepatocellular carcinoma, and more.

Cell Biology 101 – Function and Biogenesis of Cellular Membranes: The Endoplasmic Reticulum [Biology, MCAT, USMLE]

In this quick and easy lesson guide, learn about cell biology – the function and biogenesis of cellular membranes. Explain the metabolic and protein biosynthetic functions of the endoplasmic reticulum. Define key metabolic functions of the endoplasmic reticulum.

  • Illustrate the function of the endoplasmic reticulum in the cotranslational translocation of proteins made on membrane bound polysomes and their co- and post-translational modifications. Explain the function of the endoplasmic reticulum in protein folding and discuss the fate of misfolded proteins.
  • Biology 101: Gel Electrophoresis

    In this educational lesson, we learn about the purpose of gel electrophoresis and how gel electrophoresis works. Gel electrophoresis in a method of separating DNA. It can be used to separate the size of DNA, RNA, and protein. You first start with a variety of different fragments of DNA all mixed together. The gel is a porous matrix like a sponge and separates the DNA based on two main things: 1) size and 2) charge. The charge on DNA is what makes it move through the gel. DNA is a negatively charged molecule, so it will move towards a positive charge.

    Chemistry 101: At Home Awesome Chemistry Experiments

    Chemical reactions happen around us all the time. These reactions occur when we cook or bake and even in our bodies, like when we breathe. Everyday objects are able to react and cause incredible reactions. Here are some easy science experiments you can create using things you can find around the house. Make sure you act safely during the experiment and have fun!

    Digoxin: How does Digoxin treat heart failure? Mechanism of Action and Side Effects [USMLE, Biology, MCAT, Medicine]

    Digoxin is a drug that treats heart arrhythmias, left ventricular systolic dysfunction, and heart failure. In this succinct educational lesson, we learn about how digoxin works in treating heart arrhythmias and heart failure, digoxin toxicity and common side effects, and treatment for digoxin toxicity. We also have a mini quiz at the end, so you can test your knowledge on the pharmacology of digoxin.

    Immunology: Treatments for Rheumatoid Arthritis – NSAIDs vs DMARDs vs Glucocorticoids [Biology, Medicine, MCAT, USMLE]

    Rheumatoid arthritis is an autoimmune disease characterized by chronic inflammation in the joints of hands, feet, knees, etc. In this quick and easy lesson, we explain the standard medical treatment for patients with rheumatoid arthritis at the USMLE immunology level, including DMARDS (synthetics and biologics), NSAIDS, and glucocorticoids.

    Biology Unit 5 Study Guide: Evolution

    Biology Unit 5 Study Guide: Evolution. After his visit to the Galapagos Islands, Darwin came up with the theory of evolution.  This theory stated that organisms change over time.  The way that organisms change is through the process of natural selection. With examples, practice questions, and answers to help make evolution respiration easy to learn!

    Psychology and Marketing of Eating: Why Do We Eat the Way We Do?

    The overwhelming amount of commercials, advertisements, and promotional campaigns that Americans are bombarded with is astronomical, to the point it is affecting their dietary habits. As the turn from a nomadic lifestyle switched to one with steady food supplies and surplus, history of mankind derailed and took an entirely different course, one that would later involve corporations utilizing marketing communications to influence their consumers. 

    Biology Study Guide Book Just Published and on Sale! [Free Chapters]

    Hi Everyone! My friend just published a biology study guide book and it’s currently on sale! This book on biology study guides contains practice review questions and answers. Study Guides: Biology Unit Review Practice Questions and Answers . This interactive study guide of worksheets contains questions and answers to help you understand biology. Each unit contains information on key topics to review to further your understanding of biology. The units covered in this book include: ecology, biomolecules and cell biology, energy, photosynthesis, cellular respiration, cell division, mitosis, meiosis, protein synthesis, genetics, and evolution. Award-winning author and teacher Dr. Sam J. Alex created this study guide while inspired by students and teachers. All proceeds donated! Hope you find this book helpful on your journey into the wonderful world of biology and beyond!

    The Life Cycle of a Retrovirus: HIV

    Retroviruses are a class of viruses that not only infect host cells but also integrate their genetic material into the host genome, establishing a permanent infection that cannot be cured. The most common retrovirus is the human immunodeficiency virus or HIV, which targets and destroys helper T-cells.

    What is Maladaptive Daydreaming Disorder?

    Daydreaming is a common human phenomenon, one that we all experience in our daily lives. Studies show that we actually spend around 47% of our waking time in the dream world. We utilize this important tool to think-out different scenarios, re-visit special times in our lives, imagine new ones, or even just to pass time. Daydreaming is vital to the human experience. But one may wonder, what happens when one daydreams a little too much?

    Sleep 101: Brain Activity and Sleep Disorders, Sleep Apnea, Circadium Rhythms, and How to Sleep Better at Night

    Sleep and Brain Activity Sleep disorders affect up to 70 million people and cost around $15.9 billion annually. EEG stands for electroencephalography, which was used to examine human brain waves in the 1950s. Sleep Disorders: Insomnia, OSA, Apnea, Narcolepsy. Regulation of Sleep. Sleep-Wakefulness Cycle: Circadium Rhythm and Homeostatic System. Tips to sleep better at night.

    Primary Essential Hypertension vs Secondary Hypertension: Causes and Health Effects of High Blood Pressure [Biology, MCAT, USMLE]

    In this quick, easy-to-understand lesson, we learn about secondary hypertension for USMLE and medicine. Secondary hypertension is defined as high blood pressure (>140/90 or >130/80) caused by an underlying disease, medical condition, or drugs. While primary essential hypertension comprises of the majority of hypertension cases (90%), only 10% of patient cases is secondary hypertension.

    Direct Hernia vs Indirect Hernia

    Direct vs Indirect Hernia: What is the difference between direct and indirect inguinal hernias? In this easy-to-understand lesson, we explore the differences between direct inguinal hernias and indirect inguinal hernias. Overall, an inguinal hernia is a medical condition, where protrusion or bulge of abdominal contents into the groin area and/or inguinal canal. There are two types of inguinal hernias: 1) direct inguinal hernia and 2) indirect inguinal hernia.

    The Rise of Tech: Tech Trends of the COVID-19 Pandemic

    The recent COVID-19 pandemic has turned our world upside down. From the way we greet each other to the schedule of our daily routines, it’s safe to say that everything that was considered the norm at the beginning of 2020 has completely changed. While most people’s eyes are on health officials, tech giants and start-up companies have been using this time to create new inventions to propel society further – or so they say. Here we will analyze the new products and tech trends that have arisen in the wake of this pandemic, what they do, and if they actually serve to help society.

    Vaccines 101: Vaccination, Immune System, and the COVID-19 Vaccine – Benefits and Side Effects

    The question of how a vaccination would work to combat the current COVID-19 pandemic is a major concern right now. Everybody has their own perspective on the situation, and in some people’s minds, vaccines do not fit into the equation. Therefore, it’s extremely important to understand what a vaccine’s purpose is, how it is supposed to achieve that purpose, how a vaccine is developed, and its benefits versus side effects before coming to a final conclusion on the subject as it relates to the pandemic. To understand a vaccination’s purpose it is necessary to first understand how a pathogen works. A pathogen is essentially any foreign material (foreign in the sense that it is not a part of the human body), that can cause disease or a malfunction of the body. They spread from surface to surface and person to person.

    Biology 101: Microfilaments vs Microtubules in Cell Biology

    Microfilaments and microtubules are both important elements of the cytoskeleton, maintaining the structure and integrity of the cell, but there are several differences between microfilaments and microtubules. In this article, we share this information on microfilaments versus microtubules.

    Microfilament and Microtubulues are made from different individual subunits. Microfilaments are made from ACTIN, while microtubules are made from TUBULIN.

    Cardiology 101 – Atrial Fibrillation (USMLE) : Causes, Symptoms, Diagnosis, and Treatments

    In this quick easy-to-understand lesson, we learn about atrial fibrillation, causes, symptoms, diagnoses, and treatments for USMLE medicine. Atrial fibrillation is the most common type of cardiac arrhythmia. This means the heart beat has an irregularly irregular rhythm. Symptoms can include fatigue, dyspnea (difficulty breathing), and heart palpitations in the chest. You diagnose atrial fibrillation via EKG. It can be treated with medications or surgically.