Skin cells

When we are talking about skin, there are about 3 different layers, or Sections. They are the Epidermis, Dermis, and Hypodermic. The epidermis is the outermost superficial region Of the skin. The dermis is the middle region, and the Hypodermic is the deepest region of the skin. As shown below...

The epidermis is made up of Keratinized squamous epithelial, that can then be divided into four different cell types (Keratinocytes, Melanocytes, Merkel cells, and Langerhans cells). Keratinocytes produce the fibrous protein keratin. Melanocytes produce the brown pigment melanin. Langerhans' cells produce the Epidermal macrophages that help activate the immune system. Merkel cells act as touch receptors in association with sensory nerve endings. there are a few layers of the Epidermis, including the Basal layer. it is the Deepest layer of the Epidermis and is attached to the Dermis. It consists of a single layer of the youngest keratinocytes, which undergo a rapid division and that alternate its name (stratum germinativum). There is also the Stratum Spinosum (prickly layer), where Melanin granules and Langerhans' cells are running free! Each cell contains a web like system of intermediate filaments attached to the Desmosomes. Next we have the Stratum granulosum (granular layer), which has 3-5 thin cell layers where changes of keratinocyte's appearance occur. An Accumulation of keratohyaline and lamellated Granules happens in the cells of this layer. On to the next layer, formally knows as stratum lucidum (clear layer). This layer is made up of flat rows of dead keratinocytes cells. This layer is a transparent band to the granular layer. The final layer of the epidermis is the stratum cornium (horny layer). This layer is known more commonly as the outside of your skin. This layer accounts for 3/4 of the epidermal thickness. It also helps to waterproof the body, and protects from abrasions and penetrations. It even renders the body relatively insensitive to biological, chemical, and physical assaults on the body. That is it for the Epidermis layer...YAY!! Time for the Dermis...muahahahaha. The Dermis is the 2nd major skin region which contains strong, but flexible connective tissue. The cells in this payer consist of Fibroblasts, macrophages, and a few mast cells and white blood cells. It has 2 main layers, the papillary and reticular. The Papillary layer has Areolar connective tissue with collagen and elastic fibers. It has a superior surface that contains peg like projections called dermal papillae. That dermal papillae contains capillary loops, Meisser's corpuscles, and free nerve endings. Whereas the Reticular Layer accounts for approximately 80% of the thickness of skin, Collagen fibers make this possible because they add strength and resiliency to the skin. Elastic fibers provide the stretch-recoil effect on your skin. Thus ending our nice little chat about the Dermis...The Hypodermis is a Subcutaneous layer deep inside the skin, composed of adipose and areolar connective tissue.

All these skin layers help to define what "race" you are, due to a few things located in the skin. Melanin, which shifts from yellow, to reddish-brown, to black. It is associated with darker skin colors, meaning the darker your skin, the more melanin is located inside you. Freckles and pigmented moles are a result from little melanin "pockets" on your face...or wherever your freckles and pigmented moles are. There's Carotene, which is yellow and orange pigmentation of the skin. Carotene is most seen on the palms of your hands, and the soles of your feet. Now it is Hemoglobin, which turns people red, or gives you the pinkish "blush" color. It doesn't make you blush, it just makes you look pinkish. Blushing comes from a rush of blood to your face when you get embarrassed. Although there may be a differentiation in skin colors, there is one thing that almost all people in the world have in common, and that would be sweat glands. There are different types of sweat glands, such as the eccrine sweat glands, the Apocrine sweat glands, the ceruminous glands, and the mammary glands. The Eccrine sweat glands are located on your palms, soles of your feet, and your forehead. The Apocrine sweat glands are found in axillary and anogenital areas of the body. The Ceruminous gland is like a modified apocrine gland that is located in the external ear canal and secrete cerumen (ear wax). The mammary glands are specially made sweat glands that secrete milk. The Sebaceous glands (didn't mention above) is a simple alveolar gland that is found all over the body, and it soften your skins when it is stimulated by hormones. Occasionally it will secrete an oily substance called Sebum. Those are some somewhat positive things about the skin, and now the sad and depressing one, cancer.

There are 3 major forms of cancer that occur on your skin, Basal cell carcinoma, squamous cell carcinoma, and melanoma. The basal Cell Carcinoma is the least malignant and the most common of skin cancers. It's cells proliferate and invade the dermis and hyposermis, slowly growing and don't really metastasize. This type of cancer is cured via surgery in about 99% of skin cancer cases. The Squamous cell Carcinoma comes from the Keatinocytes of the stratum spinosum, and are most often on the scalp, ears, and lower lips. It will grow rapidly if it isn't removed quickly, and will metasize if not removed. The prognosis is good if treated by radiation therapy, but cutting it out works to. Preferably letting a surgeon cut it out...unless you know what your doing of course. Melanoma is the cancer of melanocytes and is the most dangerous of all the skin cancers. Seeing as how it is highly metastatic and chemotherapy doesn't work on it, it makes it extremely difficult to find some sort of cure. There are ways of identifying this cancer, using the ABCD rule. A: Asymmetry; the 2 sides of the pigmented area do not match. B: Border is irregular and exhibits indentations. C: Color (pigmented area) is black, brown, tan, and sometimes red or blue. D: diameter is larger that 6mm (size of a pencil eraser). Melanoma is normally treated by surgery with a side of immunotherapy, although the chance of survival is poor is the melanoma is over 4mm thick. Those are only 3 of the main cancers.

Time for some of the scariest kinds of injuries of the skin, Burns. There are 3 degrees of being burned, first, second, and third. In a first-degree burn, only the epidermis is damage, although it is accompanied by redness, swelling, and some pain. A second-degree burn on the other hand, damages the epidermis and the upper regions of the dermis. They include the symptoms of a first-degree burn, but they have blisters. In a third-degree burn, the entire thickness of the skin is damaged, and the burned area appears gray-white, cherry red, or black. There is no initial edema or pain, because it had destroyed whatever nerve endings were in the burned area. Doctors use the "rule of nines" in order to estimate the severity of ones burns. If over 25% of the body is covered in second-degree burns, then it is considered critical. If over 10% of the body is covered in third-degree burns, then that is critical. Although if there are third-degree burns on your face, hands, or feet, they automatically consider that critical. http://www.youtube.com/watch?v=CJt7XySKqYI <--This link will take you to a video that explains how to treat a second and third-degree burn. That would be skin, stay tuned for hair!!

Histology

Histology is the study of the Micrscopic anatomy of cells and tissues of plants and animals. You may not know it, but humans count as animals...unfortunately. The visualization of cells is achieved through usage of a light microscope, or an electron microscope. Along with the key usage of thin strips of the samples your going to look at. Histology is extremely big when it comes to Biology and Medicine. There are many classifications of cells. And they are listed below:
Epithelial-Lining of bowels , skin and glands. Along with a some organs.
Endothelium-Lining of blood and lymphatic vessels.
Mesothelium-Lining of pleural and pericardial spaces.
Mesenchyme-Cells filling space between the organs(fat, muscle, bone, etc.)
Blood cells-Red and white blood cells including those found in lymph nodes and spleen.
Neurons- conducting cells of the nervous system.
Germ cells-Reproductive cells.
Placenta- characteristic of true mammals during pregnancy.
Stem cells-Cells that develop new cells.

http://www.histology-world.com/

There is a link that takes you to a "fun and entertaining" website on histology. Although it is very entertaining to play the games, there are many other more...educational things to do on the website.

I took a microscope exam and did a lab about histology, of which I got a smiley face with a top hat...so I got an Abraham Lincoln on it. Which, I think is better than a George Washington, but maybe that's just me. It's the top hat, definitely. In the histology lab, we had to look at different samples and draw them. We looks at bone, epithelial tissue, and a funky connective tissue. We then had to draw the tissues and other cellular items that we looked at. Although the drawings that I do not have, would be a good representation of my horrible drawing ability, that was the lab.

Divisional planes

In a view of your body, there are some "primary" ways of dividing your body. One of which is sagittal, or just dividing the body into left and right parts. So you would cut straight down between the eyes, making two parallel half-people. Then there is frontal, or coronal, which divides the body into Anterior and posterior parts. Meaning this time, your would cut in half from the side, cutting both ears in half...painful. Then there is transverse, which divides your body in half Horizontally, dividing the body into upper and lower sections. There is one that is not mentioned here, and that is the
Oblique section, which divides the body diagonally thoughout the body. There you have it, the division of the body.

http://www.youtube.com/watch?v=J5COfnxIMB8&list=FL8mwj6QXDUtoT6iTJD00EVg&index=1
in this resident evil clip, the laser slices the first guy horizontally through his neck. In other words, that would be a transverse cut, although it is at the neck. The second one that was cut to bits, was cut obliquely to the utmost extreme. most oblique cuts are normally one diagonally cut and not so much as a ton of squares. But, the representation still applies, and lets face it, nobody wants to be cut into little bite sized squares.

Bodily terms

In the body, there are certain terms being used to describe certain parts. I know sounds odd right? Well, let's say that you want to describe what the front of your body looks like, you would use the word like anterior, whereas the back of your body is your posterior. It's really easy to remember because your posterior is behind you, and your anterior is in front of you. This doesn't mean necessarily your complete from of your body, you could say something like your nose is anterior to your eyes, and your eyes are posterior to your nose. Superior is you upper body, and Inferior is your lower body. The same goes for superior and inferior, although we might switch is up, and say something like, your hair is superior to your eyes, unless you have really long hair, then of which something like your hair is superior to you toes. You get the point. Medial, describes a structure towards the body's midline. Lateral is almost the same, only it describes the parts further from the median plane. Intermediate describes a structure in between the medial, and lateral plane. For example, your nose is medial to your ears, your ears are then lateral to your nose. Whereas your cheeks are intermediate of them both. Next, we come to proximal and distal. Both are describing the distance around the "trunk" (torso). Proximal means that something is closer to the torso, and distal means farther. So, we could all agree then that your foot is distal to your knee, and your knee is proximal to your foot. Superficial and deep, pretty obvious when it says deep. Deep, being deeper into your body, or simply away from your skin. And superficial is the opposite of that, being closest to your skin, or just outside of your body. So your heart is deep compared to your ribs, which would than be superficial compared to your heart.

Positive and negative feedback-homeostasis

Homeostasis, by definition is: a relatively stable state of equilibrium or a tendency toward such a state between the different but interdependent elements or groups of elements of an organism, population, or group. So when you do strenuous activities, such as running or sports, then you upset homeostasis, and you body does what it can to "adapt" to the situation. For instance, if you are running, you will overheat unless your body opens some sweat glands in order to cool your skin, and the inside of you body off. This is known as a negative feedback, because you are trying to reverse the process of your body heating. An example positive feedback is really anything that enhances your body, and as bad as it sounds, cancer is a positive feedback because of the growth hormones that it "injects" into your body. I know it sounds absolutely dreadful, but it is true. No, cancer still isn't technically a good thing...

We did a lab about homeostasis, only ours was more along the lines of who can return to homeostasis faster, after being "superheated" and "supercooled." We did only use our hand, but i think that it worked relatively the same.  As you can see from this graph, it really does depend upon who you are. As you can see, Seth and Tim were both slower that Cassidy and Jenna on returning to homeostasis from hot water. Although for cold water Seth was extremely faster in returning to homeostasis that everyone else. Whereas Tim was extremely slow compared to others. The average out of these for people to return to normal in hot water was about 5 minutes. For cold water it was about 20 minutes. which tells us that it is easier to cool down than to warm up. Interesting expirement if i do say so myself.