Earth has experienced at least five Ice Ages: the Huronian, the Cryogenian, the Andean-Saharan, the Karoo, and the Quaternary. The latest of these is the Quaternary Ice Age, which began 2.6 million years ago and is still ongoing. That might sound off given that the popular conception of an ice age is of a world blanketed in snow and roaming with wooly mammoths, but the scientific definition only requires that a substantial ice sheet be present on the Earth’s surface, and Antarctica fits the bill. While their causes vary, ice ages are typified by periods of sustained global cooling and glacial expansion. Going by this, the Little Ice Age qualifies, though it is also an ice age within an ice age, making it a sort of matryoshka doll climate event. The Little Ice Age is not the only lesser ice age, though it is the best known as it occurred the most recently and within recorded history. After having touched on similarities, our next logical step is to examine what makes the Little Ice Age different.
Drugs for TB: What drugs treat tuberculosis TB? In this quick and easy lesson, we will explain the main drugs -rifamycin, isoniazid, pyrazinamide, ethambutol, and streptomycin – that treat Mycobacterium tuberculosis or TB and provide study aid mnemonics to aid in your USMLE learning.
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.
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.
In this quick, easy lesson, we learn about hypertension, also known as high blood pressure, for USMLE and medicine. Hypertension is defined numerically as >140/90 and more recently as >130/80. Primary Hypertension vs Secondary Hypertension. Hypertension Effects. Hypertensive Urgency vs Hypertensive Emergency.
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.
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).
Standardized Tests are Necessary for Learning – True or False? A Look Into the Recent AP Testing Situation
enough, the COVID-19 pandemic has made it necessary for students to take these tests at home – and in only 45 minutes. Outrage over failed submissions and website problems has prompted the media to focus on the CollegeBoard and the real purpose and necessity of standardized testing. Is a test really enough to test a student’s true knowledge of a subject? Here, we will analyze the history of standardized testing, delve into the recent AP test situation, and consider the pros and cons of standardized tests.
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.
Aging occurs in many different ways and is a natural process of life. In this article, we delve into the definition, neurobiology and physiology of the aging process as well as tips for maximizing health and aging well.
When you hear the word “robot”, what image usually comes to mind? Is it a metallic, boxy machine? A sleek android that talks to people? A robot is a machine that is automatically operated and completes tasks in replacement for humans. Some robots are humanoid and have actions that resemble human movement, such as ASIMO (Advanced Step in Innovative Mobility), a robot created by Honda that can walk with two legs (Honda).
Psychology 101 and the Brain: Stress – Definition, Symptoms, and Health Effects of the Fight-or-Flight Response
The “fight or flight” response is in response to impending danger. For example, the stress responses kicks in when seeing a snake slithering towards you or running away from a bear in the woods. Homeostasis is the normal equilibrium of body function, so stress can be induced by belief that homeostasis might be interrupted. In this guide, we share the effects of stress on the human body system, psychology, immune system, and long-term health effects of chronic stress.
In this quick and easy biology final exam study guide, we share our notes and review the circulatory, respiratory, and lymphatic systems in the following 3 sections. From the anatomy of the heart and blood flow in the circulatory system to the breaths we take traveling through the lung and lymphatic flow.
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.
Making up around 75% of all animal species in the world, arthropods are are a vast phylum of the kingdom Animalia. The name comes from the Greek words “arthro”, meaning joint, and “podos”, meaning legs. While they all share segmented bodies with joined legs, members in this phylum vary wildly, from butterflies and millipedes, to scorpions and lobsters. They are also all invertebrates, which means that they do not have backbones. Instead, they use hard exoskeletons to protect themselves, which are made out of chitin. Because these exoskeletons are relatively inflexible, arthropods molt as they grow larger, which means they shed their exoskeletons.
Water quenches thirst, is crucial when taking a bath, and is important when cooking. Yet despite the fact that it is all around us and used in our daily lives, there are many facts and health benefits about water that remain unknown to many people.
Petroleum (or oil) and natural gas are widely used sources of fuel. Around the world many transportation, energy, and heating infrastructures depend in large part on one or both of these hydrocarbon-rich fuels, petrochemical products. While in the past it may have seemed inconceivable that people would have to step away from fossil fuels, climate change increasingly necessitates greener alternatives. It is also hard to imagine life without plastics. For many applications, such as in healthcare, there may be no better materials. A future with zero plastic is neither warranted nor desirable, but the threats to various ecosystems are likely to force the development of greener and more sustainable materials.
Innate vs Adaptive Immunity: What are the differences between innate and adaptive immunity? The human body has two protective immunological systems against pathogens: the innate immunity and the adaptive immunity. In this quick and easy lesson, we will explain the differences between the innate and adaptive immunity. The innate immunity and adaptive immunity differ based on the type of components that are used to protect the human body. For example, the innate immunity consists of neutrophils, dendritic cells, natural killer cells, macrophages, complements, physical barriers. On the other hand, the adaptive immunity contains components such as T cells, B cells, and antibodies to protect us from viruses, bacteria, and other pathogens.
Cougar. Mountain Lion. Puma. What do these animals all have in common? Believe it or not, they are actually all names for the same animal! Because this feline spans such a large area, different areas call it different names. As you might think, this could get confusing if scientists try to discuss the same animal, so what do they do? They use taxonomy.
Taxonomy is the science and process of organizing organisms into categories and naming them. Every species of animal has a unique taxonomic, or scientific, name. A species is a group of organisms that reproduce among itself and produce offspring. The scientific name is used by scientists all over the world for ease of communication. After all, it is very important to be specific in science. For example, the scientific name of the cougar/mountain lion/puma is Puma concolor. The name cougar/mountain lion/puma refers to the animal’s common name. Organisms can have many common names used by the public, but when scientists are referring to them, they use the scientific name. Domain Kingdom Phylum Class Order Family Genus Species
Climate change affects the entirety of the earth’s surface, and nowhere more so than our oceans. While our seas cover about two-thirds of the earth’s surface they absorb over ninety percent of the additional heat attributable to global warming. Both land masses and bodies of water absorb and reflect solar radiation that rebounds off of the greenhouse gases trapped in our atmosphere, but the latter is generally more absorptive and holds on to heat longer due to differences in physical properties. This of course has led to increases in global seawater temperatures, which has and continues to endanger several aquatic species. This article will examine one of those species and go over human efforts to preserve it.
In this lesson, we learn about the 3 shunts of fetal circulation: ductus arteriosus, ductus venosus, and foramen ovale of the fetal heart: functions, medical significance, when they close, medical complications, and remnant ligaments.
Ever wondered how plants grow or survive? In this educational lesson, we learn all about plant hormones, including gibberellin, auxin, cytokinins, ethylene, and abscisic acid.
For the average person, washing their hair every day or every few days is a matter of hygienic preference rather than necessity. Unless their work or pastime brings them in contact with dirt or involves physical exertion, it is unlikely that their hair would go from being clean to truly dirty in the span of twenty-four hours.
So, what is the true science behind our “dirty” hair and the ingredients in our shampoo?