“Anatomy and Physiology of the Zombie

A Discussion of Why They Cannot Exist”

Chapter 5

Stacy Gill

March 5, 2015

“Anatomy and Physiology of the Zombie

A Discussion of Why They Cannot Exist”

Looking at whether it is feasible or not for the existence of zombies, I look to the integumentary system for any possibility. I will examine the skin, subcutaneous tissue, and the aging process.
The integumentary system is the largest organ in the body, it includes the skin, hair, nails, exocrine glands, sensory receptors, and the subcutaneous tissue. On average, the skin weighs about ten pounds and has an area of about 20 square feet. It serves as a barrier between the human body and the environment. Some environmental dangers are chemicals, ultra violet light, and physical damage.
The first layer of the skin is the epidermis which covers almost the entire body. It is made up of squamous epithelial cells that are stacked up on one another. These cells produce and store keratin which makes it water resistant. Even though the epidermis is very thin it is made up of four layers.
The innermost layer is the stratum germinativum, this is where mitosis takes place. New cells are being produced constantly, while this is happening the older cells are being pushed toward the outer surface of the skin. The new cells produce keratin, in the keratinocytes, and as they move away from the blood supply they die and shed off. Approximately 8% of the epidermis is made up of melanocytes. The melanocytes produce melanin which protects the skin from the harmful UV rays.
The living keratinocytes also synthesize defensins, which play an important role when the epidermis is injured. They act against bacteria, fungi, and viruses by rupturing the membranes of the pathogen.
The epidermis also produces vitamin D. The cells of the epidermis contain cholesterol, that when exposed to the sun changes into vitamin D. Calcium and phosphorus can not be absorbed by the intestines with out the aid of vitamin D. There are other benefits to this vitamin such as bone and muscle strength, regulation of insulin, and protection against certain cancers and the flu.
The outermost layer of the epidermis is the stratum corneum. This layer has two important roles. The first being that it provides a barrier to prevent pathogens from entering the body. One way is by the flaking off of the dead cells and the second is by the secretion of sebum that inhibits growth of bacteria. The second role of this layer is the prevention of water entry and over saturating the cells.
A zombie is a non-living creature that can not exist because its skin does not contain any living cells. A zombie skin cells do not under go mitosis to produce new skin cells that are lost from flaking, the zombies skin does not produce sebum to protect it from pathogens, nor does it produce vitamin D to be used by the body to build strong bones and muscles.
The dermis is the deep layer of the skin underneath the epidermis. It is made of dense irregular connective tissue along with nerve tissue, blood, and blood vessels. The dermis is much thicker than the epidermis and gives the skin its strength and elasticity, and the resistance to wrinkling and sagging. The dermis also has accessory structures which include the hair and nail follicles, sensory receptors, glands, and blood vessels.
At the base of the hair follicle are sensory nerve fibers that surround the root of the hair. When a hair moves or has been removed the nerve ending allows humans to feel this. One of the main functions of hair is to act as a sensory touch receptor. The sebaceous glands are also associated with the hair follicle, they produce an oily secretion to help condition the hair and surrounding skin.
With the dermis we also find the nail follicle. Nails protect the ends of the fingers and toes from injury and give fingers the ability to pick up small objects. Nails consist of highly keratinized modified epidermal cells. The nail arises from the nail bed and forms a lunula. This is where mitosis takes place. The new cells produce keratin and then they die.
The sensory receptors are found in the dermis. They sense touch, pressure, heat, cold, itch, and pain. Their purpose is to inform the brain of the external environment and its effect on the skin which interprets the impulses as a specific sensation.
Exocrine glands are made of epithelial tissue. There are three major types of glands in the human body. The first is the sebaceous glands, open into the hair follicle or onto the skins surface and secretes an oily substance called sebum. The purpose is to inhibit the growth of bacteria and to prevent drying out of the hair and skin. Secondly, is the ceruminous gland which is located in the ear canal. This gland secretes cerumen which keeps the surface of the eardrum pliable and prevents it from drying out. Lastly, is the sweat glands of which there are two types. Apocrine glands are found at the underarm and the genital area and normally are triggered during stressful or emotional situations. Eccrine glands are found all over the body, but may be more abundant on the forehead, upper lip, palms, and soles. These glands are stimulated when the body needs to lower its temperature.
Last, but not least, are the blood vessels called arterioles. The smooth muscle within their walls allows for them to open and close when needed, in order to maintain a normal body temperature. When the body is too warm, the arterioles will dilate to increase the blood flow and allow heat to escape. When the body is cold, the arterioles will constrict to decrease the blood flow to keep the heat within the core of the body.
A zombie can not exist due to the fact that the dermis contains many living cells that under go mitosis and need blood flow in order to function. Zombies do not have an operating circulatory system, therefore the cells can not live. The sensory receptors also can not work because the brain is dead, hence the zombie would not have sensation of touch, cold, heat, pain, and etc. Lastly, the exocrine glands would not be able to function, since they would not be receiving signals from the nerve tissue in order to regulate body temperature.
The subcutaneous layer is the inner fat layer of the skin, which has a few different functions. The first is to provide insulation to help maintain the body's temperature when we are in cold environments. Second, is to anchor the layers of the skin to the muscles beneath the skin. Third, is to protect the muscles, bones and organs from injury. And fourth, is to act as a passageway for the blood vessels and nerves from the dermis to the muscles.
A zombie can not exist. As discussed above the zombie does not have a living nervous system or circulatory system. Both of these systems have to operate in order to regulate body temperature an to supply blood to the muscles and nerves.
As people grow older, the layers of the skin become thinner, repairing of the skin process is slower, and the skin starts to wrinkle and sag. The melanocytes die and the hair becomes gray or white. The sweat glands become less active, the skin is more likely to burn, and the amount of fat normally is less, which makes older people more sensitive to the heat and cold. When all of the processes of the skin cease the body dies.

Works Cited

Scanlon, Valerie C. and Tina Sanders. “Essentials of Anantomy and Physiology.” Philadelphia. FA Davis. 2007. “Integumentary System”. Innerbody. Taylor, Tim. H http://www.innerbody.com/anatomy/integumentary 3. “Integumentary System”. Anatomy and Physiology. San Antonio, TX. 2006. http://www.mybiologyweb.com/FTP 4. “Structure and Function of the Epidermal Barrier”. American Journal of Infection Control. Wickett, R. Randall and Marty O. Visscher. Cincinnati, OH. December 2006. http://www.ajicjournal.org/article/S0196-6553(06)0095 5. “Structure of the Skin: Dermis”. https:// www.boundless.com/physiology/textbooks 6. “Subcutaneous Tissue Layer: Definition & Injections”. http://education- portal.com/academy/lesson/subcutaneous 7. “Hair Follicle Anatomy”. Medline Plus. Bethesda, MD 2013. http://www.nlm.nih.gov/medlineplus 8. “The Integumentary System”. M.J. Farabee. 2001. http://www2.estrellamountain.edu/faculty 9. “Subcutaneous Tissue Layer: Definition”. Crawford, Adrianne. http://www.study.com/academy/lesson/sub