Histology of Epithelial Tissue
Epithelium is one of the four basic tissue types (the other three are muscle tissue, nerve tissue, and connective tissue). It is found throughout the body—covering it; lining organs, vessels, and cavities; and forming glands. It absorbs nutrients, transports electrolytes, secretes hormones, and regulates body temperature by producing sweat. We begin with some general principles…
Read MoreProkaryote Structure and the Gram Stain
What do you know about prokaryote structure and the gram stain? Bacteria are members of a unique taxonomic kingdom consisting of prokaryotic unicellular organisms. Prokaryote is a term from ancient Greek meaning “before the kernel.” The kernel in this case is a nucleus, which prokaryotes lack. Prokaryotes also do not have any membrane-bound organelles. In…
Read MoreIntroduction to Global Health
What Is Global Health? In our increasingly interconnected world, health challenges transcend national boundaries and demand global solutions. Global health is an interdisciplinary field of study and practice that seeks to improve the health and well-being of populations worldwide, focusing on the health challenges that require global and national action in every country. It encompasses…
Read MoreImmunology: Foundations and Frameworks
How do we survive in a complex environment filled with harmful organisms that thrive on colonizing us? Our heroic defender is the immune system, a network of organs and cell lines that exist with the mission of protecting the body from harm. While we often recognize the pathogen-fighting capabilities of the system, we can sometimes…
Read MoreGluconeogenesis
In the fed state, glucose is used by almost all the cells in the body to generate energy. But even when we are not fueling it with food, our bodies still run well, such as during sleep. Gluconeogenesis is the process of synthesizing glucose from noncarbohydrate precursors. The major substrates (substances that enzymes act on)…
Read MorePlasma Composition
When you hear the word blood, what do you picture in your mind? Most likely, your brain conjures up an image of thick, red liquid. But what would blood look like if you removed all the red cells? You’d be left with a murky yellowish liquid that would clear up once you removed the white…
Read MoreHemophilia (Re-release)
Hemophilia is a bleeding disorder resulting from defects in factors of the coagulation cascade. There are two primary types of hemophilia: A and B. Both types of hemophilia are rare, with only a combined frequency of about 1 in 5000 live births. Of the two types, hemophilia A is about four times more common. In…
Read MorePain Mechanisms
Pain is a sensation that warns of potential injury and alerts the person to avoid or treat it. For example, if you touch a hot object, you will feel pain and immediately remove your hand from that object, protecting your hand from further damage. As much as pain can burden and torment, ultimately it is…
Read MoreGastrointestinal Regulatory Substances
As we eat, our gastrointestinal (GI) system releases a host of both local and distant regulators to control the process of digestion. We will begin with the primary hormones, then cover some of the secondary hormones, and lastly discuss how our body senses its intraluminal contents and then subsequently integrates all of the various stimuli…
Read MoreMigraine, Cluster, and Tension Headaches
Headaches are an unavoidable fact of life and often are nothing more than the result of sitting through one too many lectures. However, they can become debilitating and get in the way of daily life, especially when they become recurrent. Although some headaches have symptoms other than head pain, we typically think of headache pain…
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