Tag: medical

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.

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.

    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.

    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.

    Embryogenesis: Definition, Stages, and Development [MCAT]

    Sonic Hedgehog Gene. CNS development and Limb development. In embryology and developmental biology, embryogenesis is the development of an animal or plant embryo, starting with fertilization of an egg cell by a sperm cell. After fertilization, the ovum becomes a diploid zygote. orms forebrain, separates right and left brain, and establishes midline. f there’s a mutation, then we have a whole brain with no separation of right and left, which is bad. This is called holoprosencephaly. Left and right hemispheres fail to separate. There are also facial abnormalities, cleft lip/palate and even severe cyclopia (single eye like a cyclops).

    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.

    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.

    Cardiac Arrhythmias: Definition, Types, Symptoms, and Prevention

    The heart’s function is to consistently move the blood in the body for the blood to spread nutrients to other body parts or to be replenished with oxygen and nutrients from other respective organs. The heartbeat is a way to understand the pace at which the blood is moving and how quick the heart is pumping itself. A heartbeat changes based on its environment. Running and high-intensity movement causes the heart to increase its number of beats whereas resting may lead to a lower heartbeat for the low amount activity that does not require as much oxygen. Depending on the difficulty and intensity of each activity, the heart accommodates via changing its pace to fit the body’s needs. In certain cases, however, a cardiac arrhythmia occurs and can lead to different cardiac issues that may or may not be harmless. Cardiac arrhythmia has affected millions of people in a multitude of forms. This article explains the basics of this condition such as heart block and bradycardia. The article is solely for educational purposes and not to diagnosis. What is a Cardiac Arrhythmia?

    Eyes 101: Top 25 Most Common Eye Problems, Diseases, and Disorders

    Common eye problems, diseases, and disorders – Quick and easy to learn diagram, definitions, and explanations for common eye diseases. In this article, we explore the top 25 most common eye problems, diseases, and disorders, including diagrams,  definitions, and explanations for common eye diseases. The eye is a small but unique organ of the human body with the ability to visualize a lifetime of events. 

    Is COVID-19 Going to Resurge? In the Winter? When Will the COVID-19 Pandemic End?

    The novel COVID-19 is leaving astonishing traces of deaths and illnesses as it rapidly encroaches upon our everyday lives. Schools are closed. Unemployment is surging. People experience dreadful losses of their family and friends. Luckily, however, the exponential curve of COVID-19 seems to have flattened within the past few weeks for many of the countries, and some even seem to have downward-sloping trends. So, should we feel relieved and expect the curve to hit 0 soon?