The Demon in the Freezer

Smallpox Virus

For my literacy glog, I chose The Demon in the Freezer by Richard

Book Cover

Preston. After reading The Hot Zone last year, also by Preston, I heard that he wrote another book about smallpox. I wanted to read it, and it turns out to be on the reading list, a lucky coincidence. The book is about smallpox, its eradication in 1979 and the process that the medical professions went about to exterminate the disease. I can't imagine getting smallpox after reading what some people had to go through, pretty frightening stuff! Living in a time with no vaccines for viruses like smallpox would feel as if there was no hope. Preston discusses a lot of history, which I don't like much, but he makes it really interesting! He tells of only two stores of smallpox that were kept, but other nations have it, and they can easily set it loose as a biological weapon. This is an interesting yet frightening idea. Preston makes the history interesting, involving commentary from the individuals who actually put an end to the spread to the smallpox virus. He includes always intriguing observations, and I'm excited to learn what happens next.

 Smallpox Virus Image From http://catherineryanhoward.com/2010/11/26/what-i-thought-of-the-demon-in-the-freezer-by-richard-preston/
Book Cover Image From http://www.homeshop18.com/demon-freezer/author:richard-preston/isbn:9780345466631/books/science/product:20146140/cid:13683/?it_category=hs18bot&it_action=sameCategoryBooks&it_label=20146140&it_value=2

Skin...Our Personal Bodyguard

Man enjoying the cooling benefits of sweat

Skin is pretty amazing. It is your largest organ and protects you from the outside environment. The skin is designed to protect you from mechanical, chemical and biological damage. The parts that make up the skin are perfectly suited to their jobs. First, the skin is made up of three layers: the Epidermis (outer layer), Dermis (middle layer), and Hypodermis (deepest layer). The Hypodermis isn't actually part of the skin, it just anchors it to the underlying organs, but for now we'll just include it. The outermost layer, the epidermis has an outermost layer of dead cells, so they can be sloughed off without damage to the underlying  layers. Pretty cool right? And even if the damage is deeper than the epidermis and enters the dermis, it's all good. The dermis is made of dense connective tissue, and strong substance designed to protect the organs underneath. Not only does the skin have these three layers, it also has hair and ducts that secrete substances that protect us. The hair increases the sensitivity of the skin, and allows tissue to regenerate in the hair follicles, where it wouldn't be able to regenerate somewhere else. Sebum and sweat are the substances secreted by the skin to protect it. Sebum keeps our skin and hair hydrated and creates an acid barrier that protects us from chemical and biological factors, like bacteria. The skin also regulates the temperature of our body. There are several ways for our body to cool down, including sweating and vasodilation (expansion of vessels). This expansion brings the blood closer to the surface, allowing heat to escape. Vasoconstriction (contraction of vessels) brings blood away from the surface preventing heat loss. Vasocontstriction, along with goosebumps keep the body warm and cozy. Another function of the skin is to protect the body from UV radiation. The skin has these things called melanocytes that produce melanin, which is partly responsible for skin color. Increased exposure to the sun generates more melanin, which darkens the color of the skin (a tan). The darker color actually acts as a barrier to block out some UV rays. So the skin will actually change to protect itself from harmful radiation. Skin is pretty amazing; I don't know what we would do without its protection.

Sweating Man Image From http://en.wikipedia.org/wiki/Perspiration

A Tale of Two Tissues...Form Meets Function

Stratified Squamous Epithelial Tissue

Tissues are one of the most diverse structures in the human body. They can stretch, protect and filter  to fill the needs of the body. The diversifying element in tissues are their form. Different form, different function. For example, simple squamous tissue is a single layer of small cells that are used for absorption, secretion, and exchange of substances. Their small shape allows for quicker diffusion, like in the lungs where gases need to be exchanged efficiently. Stratified Squamous has a similar name but a remarkably different function. Stratified tissue has multiple layers and in this case is used where friction is often found. This way a layer can be removed and the body is not harmed. Stratified Squamous tissue makes up the skin, mouth, and esophagus. Imagine you get scraped by something, and you're down to the muscle? Not a pretty sight, and this is exactly why multiple layers are absolutely essential. These are both types of Epithelial Tissue. Other types include Connective, Muscle, and Nervous Tissue. Each of these three Tissue types has a radically different function, yet they are all tissues. 

Potatoes

Tissues are like potatoes- there are different functions for potatoes (mashed, baked,  or made into a  delicious salad), but in the end they are all potatoes. Getting back to tissues, there are even different shapes they can be. Long, short, or something in between. They can be stretchy, hard, and even pliable.As mentioned in the video, there are many very different functions of silk. It can be made into clothes, but can also filter and be woven into ropes. Concerning tissues, the point of having all these forms, and therefore functions is to create a diversity of capabilities, and support homeostasis. A single type of tissue cannot maintain homeostasis alone. Nervous tissue can sense stimuli and send a signal to muscles to expand or contract. The tissue on the skin (stratified squamous) keeps out foreign invaders and maintains internal temperature. This isn't just a tale of two tissues, it is a tale of many that work together to keep the body in tip top shape. 

Stratified Squamous Tissue Image From http://www.stegen.k12.mo.us/tchrpges/sghs/ksulkowski/TissueSlides.htm
Potatoes Image From
http://www.foodsubs.com/Potatoes.html