In a Fox News interview Jill Davis described being tormented by her superb memory and the difficulty of remembering things a person would rather forget. We all would like to have a better memory, but would most of us really want an overwhelming flood of memories from age 14 on? Constantly playing in our heads? Good times and bad? … in vivid detail?

Jill Price is diagnosed with hyperthymestic syndrome — a condition of continuous, automatic, autobiographical recall of every day of a person’s life.

Fox News co-anchor asked Jill if she could remember the date of Easter in 1980 and Jill answered, ‘April 6.’ A quick check on Google found this top search result … http://parish.ashtead.org/easterdate.htm

Jill Price was right!

Scientists want to study Jill for Alzheimer research.

Check out her book for this amazing story.

A study of 361 men under 40 who were being evaluated for infertility, excluding men with infertility problems among men with personal or family history, found a strong association between length of time spent on a cellphone and sperm count and quality.

Ashok Agarwal and scientists at the Clevelenad Clinic Fondation andrology lab divided the patients into four groups, based on how long they said they talked on a cellphone each day (A: no use; group B: <2 h/day; group C: 2-4 h/day; and group D: >4 h/day). Those who talked more than four hours a day had lower counts and a greater amount of  poor “swimmers” and abnormally formed sperm.

The study is preliminary and leaves many questions unanswered:

The study concludes that the use of cell phones decrease the semen quality in men by decreasing the sperm count, motility, viability, and normal morphology.

Cellphones emit radiofrequency electromagnetic waves, which scientists say, have potential adverse effects of the waves on the brain, heart, endocrine system and DNA.

SOURCE:
Agarwal A, Deepinder F, Sharma RK, Ranga G, Li J. Effect of cell phone usage on semen analysis in men attending infertility clinic: an observational study. Fertil Steril. 2008 Jan; 89(1):124-8. Epub 2007 May 4.

Three-stage Inspection:
Stand straight in front of a mirror. Know the symmetry of your breasts. Asymmetry you’re born with may be normal, so it is important to know your breast characteristics and then be able to detect any change. Changes might be a sign that something has gone wrong. On visual inspection you are looking for any change in shape, size and outline; puckering or dippling; nipple crustiness; nipple itching; nipple bleeding, nipple inversion.

Repeat inspection with arms raised overhead

Repeat inspection leaning forward.

Two-stage Palpation:
Palpation is easier to perform when skin is wet or damp, so a good time to do a self-breast examination is in the shower or bath.

(1) Use the flat, pad part of your fingers not your fingertips. With circular motion start at the nipple and feel for distinct lumps or swelling. Proceed all the way into the armpits. In the armpits also look for lumps in the armpit region that could be swollen glands.

(2) Also press the whole flat part of the palm to press the breast against the rib cage. Lumps can be detected by the palm of the hand

Self-breast examination demonstration: Look for usual size, shape and color. Look for distortion, swelling, dimpling, puckering and change in nipple shape, such as pushed in or pushed out. Also look for redness or rash.

Sixty percent of breast cancers are found in the outer quarter (doctor points lateral and superior) region of the breast.

See also:
Avon Walk for Breast Cancer
BreastCancer.org
Cancer.gov
MedlinePlus: Breast Cancer
TheFamilyGP.com

Although circumcision does not offer 100% protection, it does provided significant risk reduction of health-related problems related to sexually transmitted disease. Differences exist between hetersosexual sex and homosexual sexual activity. Other risk factors are also important besides circumcision.

Circumcision of males represents a surgical “vaccine” against a wide variety of infections, adverse medical conditions and potentially fatal diseases over their lifetime, and also protects their sexual partners. In experienced hands, this common, inexpensive procedure is very safe, can be pain-free and can be performed at any age. The benefits vastly outweigh risks. The enormous public health benefits include protection from urinary tract infections, sexually transmitted HIV, HPV, syphilis and chancroid, penile and prostate cancer, phimosis (a condition where the foreskin cannot be fully retracted from the head of the penis), thrush (fungal infection affecting the mouth or vagina), and inflammatory dermatoses. In relation to women, circumcision of the male partner provides substantial protection from cervical cancer and chlamydia. Circumcision has socio-sexual benefits and reduces sexual problems with age. It has no adverse effect on penile sensitivity, function, or sensation during sexual arousal. Most women prefer the circumcised penis for appearance, hygiene and sex. Given the convincing epidemiological evidence and biological support, routine circumcision should be highly recommended by all health professionals.

Little scientific evidence of adverse effects on sexual, psychological, or emotional health was found by researchers; but, surgical risks associated with circumcision, such as bleeding, penile injury, and local infection, and the consequences of pain experienced with neonatal circumcision are valid concerns.

Important Findings of Circumcision Related to HIV/AIDS
One African study found no seroconversions (HIV negative to HIV positive status) among 50 circumcised male partners in heterosexual relationships. In the study in rural Uganda, researchers examined the influence of viral load in relation to other risk factors for the heterosexual transmission of human immunodeficiency virus type 1 (HIV-1). In a community-based study of 15,127 persons in a rural district of Uganda, researchers identified 415 couples in which one partner was HIV-1-positive and one was initially HIV-1-negative (a sero-discordant couple) and followed them prospectively for up to 30 months. The incidence of HIV-1 infection per 100 person-years among the initially seronegative partners was examined in relation to behavioral and biologic variables.

The male partner was HIV-1-positive in 228 couples, and the female partner was HIV-1-positive in 187 couples. Ninety of the 415 initially HIV-1-negative partners seroconverted (incidence, 11.8 per 100 person-years). The rate of male-to-female transmission was not significantly different from the rate of female-to-male transmission (12.0 per 100 person-years vs. 11.6 per 100 person-years). The incidence of seroconversion was highest among the partners who were 15 to 19 years of age (15.3 per 100 person-years). The incidence was 16.7 per 100 person-years among 137 uncircumcised male partners, whereas there were no seroconversions among the 50 circumcised male partners (P<0.001). The mean serum HIV-1 RNA level was significantly higher among HIV-1-positive subjects whose partners seroconverted than among those whose partners did not seroconvert (90,254 copies per milliliter vs. 38,029 copies per milliliter, P=0.01). There were no instances of transmission among the 51 subjects with serum HIV-1 RNA levels of less than 1500 copies per milliliter; there was a significant dose-response relation of increased transmission with increasing viral load. In multivariate analyses of log-transformed HIV-1 RNA levels, each log increment in the viral load was associated with a rate ratio of 2.45 for seroconversion (95 percent confidence interval, 1.85 to 3.26).

The researchers concluded that viral load is the chief predictor of the risk of heterosexual transmission of HIV-1, and transmission is rare among persons with levels of less than 1500 copies of HIV-1 RNA per milliliter.

Another study in three U.S. cities of homosexual black and Latino men who have sex with men found no evidence that circumcision offered protection against HIV infection.

There is a biological rationale that the increase surface area of the uncircumcised foreskin increases risk of HIV infection due to the high density of HIV target cells and lack of keratinization of the inner mucosal surface of the foreskin.

One researcher reviewed medical literature to study AIDS and hetersosexual anal intercourse and suggested the following: (1) anal coitus carries a greater risk to women than does vaginal intercourse; (2) it is probable, but unknown whether women having receptive anal intercourse with bisexual men are at a greater risk than those with heterosexual partners; and (3) female-to-male transmission of HIV is not considered as likely in Western countries as is male-to-male transmission.

SOURCES:

Jin F, Prestage GP, Zablotska I, Rawstorne P, Kippax SC, Donovan B, Cunningham PH, Templeton DJ, Kaldor JM, Grulich AE. High rates of sexually transmitted infections in HIV positive homosexual men: data from two community based cohorts. Sex Transm Infect. 2007 Aug;83(5):397-9. Epub 2007 Jun 7.

Quinn TC, Wawer MJ, Sewankambo N, Serwadda D, Li C, Wabwire-Mangen F, Meehan MO, Lutalo T, Gray RH. Viral load and heterosexual transmission of human immunodeficiency virus type 1. Rakai Project Study Group. N Engl J Med. 2000 Mar 30;342(13):921-9.

Millett GA, Ding H, Lauby J, Flores S, Stueve A, Bingham T, Carballo-Dieguez A, Murrill C, Liu KL, Wheeler D, Liau A, Marks G. Circumcision Status and HIV Infection Among Black and Latino Men Who Have Sex With Men in 3 US Cities. J Acquir Immune Defic Syndr. 2007 Dec 15;46(5):643-650.

Morris BJ. Why circumcision is a biomedical imperative for the 21(st) century.  Bioessays. 2007 Nov;29(11):1147-58.

Moses S, Bailey RC, Ronald AR. Male circumcision: assessment of health benefits and risks. Sex Transm Infect. 1998 Oct;74(5):368-73.

Voeller B. AIDS and heterosexual anal intercourse. Arch Sex Behav. 1991 Jun;20(3):233-76.

Weiss HA. Male circumcision as a preventive measure against HIV and other sexually transmitted diseases. Curr Opin Infect Dis. 2007 Feb;20(1):66-72.

Keywords: Sero discordant, AIDS, HIV, homsexual
, gay, circumcized, circumcision, circumcised, curcumcision, curcumcizion, circlecision, curcmcision, circmcision, circmscion, crcmscion, crcmcision, cirumcision, hood

Benjamin Horne, a heart disease researcher from Intermountain Medical Center and the University of Utah in Salt Lake City led a study that found that among behavioral patterns of 515 people surveyed, only fasting made a significant difference in heart disease risks. Fifty-nine percent of periodic meal skippers were diagnosed with heart disease compared to sixty-seven percent heart disease among people who did not periodically fast. Fasting was defined as skipping two consecutive meals.

The factors that were examined included body weight, blood cholesterol levels, blood pressure, diabetes, family history of Coronary Artery Disease (CAD), monthly fasting, avoiding tea, avoiding coffee, avoiding alcohol, religious persuasion, taking a weekly day of rest, going to church, social support metrics and donating time, goods or money to charity. Many of the behaviors were due to subjects being Mormons, but 8 percent of subjects surveyed were not Mormons and were consistent with study results.

Horne declared that this one study does not prove that one day fasting per month reduces heart disease, but it does bring the conclusion that a further look into one-day fasting is worthy of more research. Horne also reminded people that fasting slows down the metabolic rate, which stores more calories when eating resumes [Exercise Reports note: that means people trying to lose weight should be ready to increase exercise immediately after the fast to burn off the extra calories or burn the extra nutrients before they are even stored].

Horne postulated that one day fasting might:

Reports in the 1970’s suggest that Latter-day Saints (LDS, or Mormons) in Utah have lower cardiac mortality compared to other Utahns and the US population.

SOURCE:
Brian S McClure, Heidi T May, Joseph B Muhlestein, Jeffrey L Anderson, Dale G Renlund, Beau M Bailey, and Benjamin D Horne
Abstract 3642: Fasting, a Novel Indicator of Religiosity, may Reduce the Risk of Coronary Artery Disease Circulation, Oct 2007; 116: II_826 – II_827.

The ability to hold and use information in the mind for immediate access is known as “working memory.” Examples are remembering numbers for math calculations or for dialing a telephone number. Working memory also involves holding information while other relevant tasks are performed. Working memory capacity varies from person to person. A recent study by Dr Torkel Klingberg and Fiona McNab at the Stockholm Brain Institut, Karolinska Institutet found that a good working memory capacity may not be attributed to having larger memory storage, but to having a better filter that keeps out irrelevant information.

The study involved functional magnetic resonance imaging (fMRI) of 25 healthy volunteers that performed a computer-based task that focused on visual images with or without irrelevant distractions. A noise alerted test subjects that irrelevant information was about to be presented.

The subject’s brains (specifically the prefrontal cortex and the basal ganglia) responded to the sound ahead of the distractions. The fMRI showed greater activity in the globus pallidus located in the basal ganglia that correlated with less unnecessary storage in the posterior parietal cortex— an area of the brain related to the amount of information held in memory. The preceding frontal and basal ganglia activity was correlated with inter-individual differences in working memory capacity of the test subjects.

The scientists had the intent of investigating attention deficit hyperactivity disorder (ADHD) in children.

SOURCE:
McNab F, Klingberg T. Prefrontal cortex and basal ganglia control access to working memory. Nat Neurosci. 2007 Dec 9; [Epub ahead of print]

BACKGROUND INFORMATION:
Search results: working memory from PubMed.gov

FOX NEWS segment on Nutty Buddy.

Product testing of the Nutty Buddy — A Juggs Baseball Pitching Machine sends a baseball to the groin of Mark Littell. Don’t try this at home!

I’m one mean, tough guy” says Mark Littell. “But I think the Nutty Buddy is tougher.”

Lacy, a high school student from a high school in Helena, Montana drops a ball in the pitching machine.  The baseball makes a direct hit on a protective cup over the underlying penis and testicles of Mark Littell. He doesn’t even flinch and a roar of laughter rises from the surprised audience on the baseball diamond.

Yeah, all the way; … and it works

Right there for you every time!”

— Mark Littell

“A direct blow usually puts you on your knees, but he didn’t even flinch. But there must be something the way it disperses the hit that it doesn’t … uh … that you don’t feel it in the … uh …  testicles.”

— Chris Sabo, former MLB player

Mark Alan Littell (January 17, 1953 in Cape Girardeau, Missouri),  professional baseball player — pitcher in the Major Leagues from 1973-1982. He played for the St. Louis Cardinals and Kansas City Royals. Littell had a lifetime ERA of 3.32 and saved 56 games from 1976 to 1981. His career was cut short by the development of elbow spurs.

More info …
nuttybuddy.com

Left elbow, showing medial and lateral views.

The elbow joint is a ginglymus or hinge joint. Three bones form the elbow joint: the humerus of the upper arm, and the radius and ulna — the main pair of bones of the forearm. The bony prominence at the very tip of the elbow is the olecranon process of the ulna. The radius is positioned laterally to the ulna at the elbow joint.

Two main actions or movements are possible at the elbow:

The combined motion of these joints allows a range of motion from 5-150° of flexion-extension and 75° of pronation to 80° of supination. Remember that the olecranon process of the ulna sits in the humeral olecranon fossa in 20° or less of flexion.

In the anatomical position (with the forearm supine or in supination), the radius and ulna lie parallel to each other. During pronation, the ulna remains fixed, and the radius rolls around it at both the wrist and the elbow joints. In the prone position, the radius and ulna appear crossed.

During exertion, most of the force through the elbow joint is transferred between the humerus and the ulna. Very little force is transmitted between the humerus and the radius. Interestingly — and in contrast — at the wrist joint, most of the force is transferred between the radius and the carpus, with the ulna attenuating little force in the wrist joint.

Muscles, arteries, and nerves

The muscles in relation with the joint are:
Anterior:
Brachialis

Posterior:
Triceps brachii and Anconeus

Lateral:
Supinator, and the common tendon of origin of the forearm Extensor muscles

Medial:
The common tendon of origin of the forearm Flexor muscles, and the Flexor carpi ulnaris.

The arteries supplying the joint are derived from the anastomosis between the profunda and the superior and inferior ulnar collateral branches of the brachial, with the anterior, posterior, and interosseous recurrent branches of the ulnar, and the recurrent branch of the radial. These vessels form a complete anastomotic network around the joint.

The nerves of the joint are a twig from the ulnar, as it passes between the medial condyle and the olecranon; a filament from the musculocutaneous, and two from the median.

Ligaments of the elbow
The trochlea of the humerus is received into the semilunar notch of the ulna, and the capitulum of the humerus articulates with the fovea on the head of the radius. The articular surfaces are connected together by a capsule, which is thickened medially and laterally, and, to a less extent, in front and behind. These thickened portions are usually described as distinct ligaments. The major ligaments are the ulnar collateral ligament, radial collateral ligament, and annular ligament. The ligaments are actually thick extensions of the capsule, rather than true ligaments. Of the 3 medial structures, the anterior medial collateral ligament (AMCL) is the most important, providing approximately 70% of the valgus stability. On the lateral elbow, the lateral ulnar collateral ligament (LUCL) is the strongest of the 4 branches, providing varus support.

X-ray showing a flexed elbow (left), and an extended right elbow (right) that shows the angle of the humerus compared to the radius and ulna.

Carrying Angle
When the arm is extended, with the palm facing forward or up (supination), the upper arm is not in straight alignment with the forearm. The deviation from a straight line (generally on the order of 5-10°) occurs in the direction of the thumb (in supination), and is referred to as the carrying angle (visible in the right half of the picture of x-ray above). In females the carrying angle is usually greater than the carrying angle in males.

The carrying angle can influence how objects are held by individuals and may decrease efficiency of elbow flexion and elbow flexion force production. Increased carrying angle causes increased valgus stress on the medial structures of the elbow.

Hyperextension
Some individuals are also born with elbows that have a larger range of motion with hyperextension. The elbow may be subject to instability and pain and by slightly dysfunctional if it is capable of hyperextended range of motion.

Elbow Injury Risk
Elbows are at risk of overuse injuries and accidental trauma. Structures in the elbow that are subject to injury are bones, ligaments and muscle tendons. Nearby muscles can also be a source of problems. The following conditions are associated with elbow medical issues: biceps tendinosis, biceps tendinopathy, biceps tendonitis, anterior capsule strain, pronator syndrome, median nerve compression syndrome, lateral epicondylitis (tennis elbow), medial epicondylitis (tennis elbow), radial tunnel syndrome, posterior interosseous nerve compression syndrome, triceps tendinosis, triceps tendinopathy, triceps tendinitis, olecranon impingement syndrome, posterior impingement syndrome, hyperextension valgus overload syndrome, boxer’s elbow, olecranon stress fractures, radiocapitellar chondromalacia, and posterolateral rotatory instability.

Activity that causes increased valgus stress on the elbow can cause ulnar nerve injury, posterior impingement syndrome, or olecranon stress fractures.

Fractures
The elbow and forearms in sports are often involved in contact with other players, the floor or ground during falls or catches. Elbows can also be hit by pitches in baseball or hockey pucks in hockey.

Pitchers with excessive innings are more likely to

Tennis Elbow

Triceps tendinitis

Idioms of the elbow
at my elbow
within convenient reach

elbow grease
Performing hard work, especially when you are cleaning or rubbing something

elbow room
1. space to move around. 2. unrestrained thinking for better creativity and politics — the freedom to think what one wants.

give the elbow
to break off a romantic relationship

more power to your elbow
to wish someone good luck

rub elbows
to hang out or get the opportunity to talk with someone who is famous or accomplished in their field

The thumb, unlike other fingers, is opposable, in that it is the only digit on the human hand which is able to oppose or turn back against the other four fingers, and thus enables the hand to refine its grip to hold objects which it would be unable to do otherwise. The opposable thumb has helped the human species develop more accurate fine motor skills. It is also thought to have directly led to the development of tools, not just in humans or their evolutionary ancestors, but other primates as well. The thumb, in conjunction with the other fingers make humans and other species with similar hands some of the most dexterous in the world.

There are four types of grips related to the thumb: Pinch, hold and full grasp.

Pinch involves the tips of the thumb and second finger (forefinger/index finger). An example is holding a pill or pinching skin.

Hold involves the thumb, second finger and third finger (middle finger). An example is holding a pencil.

Full Grasp involves the thumb and all fingers. An example is holding barbell or a dumbbell, suitcase, or high bar for chin-ups or pull-ups.

False Grip involves exercise when an athlete takes the thumb out of opposition to the fingers in the grip. The athlete places the thumb under the bar (e.g., in bench press) or over the bar (e.g., in a triceps pressdown). Use of the false grip changes the co-action of muscles that are used to perform an action or exercise. In other words, slightly different muscle action occurs for the purpose of isolating or focusing action on a certain muscle or alleviating stress and strain on certain muscles or joints. Also known as the “suicide grip” because in the bench press, the bar is essentially balanced on the palm of the hands and can roll of suddenly and quickly and fall on the athlete’s head or chest causing injury or death. A spotter or spotters cannot counter this accident.

Thumb movements are controlled by eight muscles (each with “pollicis” in the name):

Name                       Location    Nerve  
extensor pollicis longus   forearm     posterior interosseous n.
abductor pollicis longus   forearm     posterior interosseous n.
flexor pollicis longus     forearm     anterior interosseous n.
extensor pollicis brevis   forearm     posterior interosseous n.
abductor pollicis brevis   hand        median nerve n.
flexor pollicis brevis     hand        median nerve
opponens pollicis          hand        median nerve
adductor pollicis          hand        ulnar nerve (deep branch)

The extensor pollicis longus tendon and extensor pollicis brevis tendon form what is known as the  anatomical snuff box (an indentation on the lateral aspect of the thumb at its base) The radial artery can be palpated anteriorly at the wrist(not in the snuffbox) In the hand, the abductor pollicis brevis, adductor pollicis, flexor pollicis brevis, and opponens pollicis form the thenar eminence,  the body of muscle on the palm of the human hand just beneath the thumb. The skin overlying the thenar eminence is the area stimulated when trying to elicit a palmomental reflex.

The muscles of the area of the thenar eminence are usually innervated by the recurrent branch of the median nerve, except for the adductor pollicis, which is supplied by the deep branch of the ulnar nerve. They all control movement of the thumb.

Adductor pollicis draws the 1st metacarpal laterally to oppose thumb toward center of palm and rotate it medially.

Abductor pollicis brevis abducts the thumb. This means that if the hand was laid flat so the palm faced upwards, this muscle would point the thumb upwards. This muscle is the most proximal of the thenar group.

Flexor pollicis brevis, which lies next to the abductor, will flex the thumb, curling it up in the palm.
Opponens pollicis lies deep to abductor pollicis brevis. As its name suggests it opposes the thumb, bringing it against the fingers. This is a very important movement, as most of our dexterity comes from this action.

The innervation of these muscles by the median nerve is unusual, as most of the intrinsic muscles on the palm of the hand are supplied by the ulnar nerve. The lateral two lumbrical muscles are the other exception.

Another muscle that controls movement of the thumb is adductor pollicis. It lies deeper and more distal to flexor pollicis brevis. Despite its name, its main action is mainly rotation and opposition. It is not in the thenar group of muscles, so is supplied by the ulnar nerve.

Palmomental reflex
When the thenar eminence is stroked briskly with a thin stick, from proximal (edge of wrist) to distal (base of thumb) using moderate pressure. A positive response is considered if there is a single visible twitch of the ipsilateral mentalis muscle (chin muscle on the same side as the hand tested). The palmomental reflex (PMR) is an example of a primitive reflex — present in infancy, but disappears during maturation of the brain during childhood. The PMR may reappear due to processes that disrupt the normal cortical inhibitory pathways.

Marinesco and Radivici in their seminal paper hypothesize that both the afferent (receptive) and efferent (motor) arms of the reflex are on the same side (ipsilateral) to the hand stimulated; however this hypothesis remains unsubstantiated.

The PMR has been found to be present more frequently in various neurological conditions both localized and diffuse. These include congenital conditions such as Down’s syndrome where it is unclear whether the reflex persists throughout life or disappears and then re-appears in association with the onset of Alzheimer’s disease pathology. The reflex is common in the elderly population and should not be taken as indicative of a dementing process


Expressions and idioms regarding the thumbs

all thumbs
Lacking physical coordination, skill, or grace; clumsy … as if the person doesn’t know how to use all fingers to perform a complex hand action or grasp.

rule of thumb
A general guide for determining behavior, a quick calculation or a custom. May have originated from the use of the thumb to measure something in the absences of a ruler. Often used in re
ference to emergencies when there isn’t enough time to diligently and carefully calculate a response.

thumb (one’s) nose
To express scorn or ridicule by or as if by placing the thumb on the nose and wiggling the fingers.
thumbs down or sometimes to just stick one’s nose in the air in disgust or condescension to another person.

thumbs down
An expression of rejection, refusal, or disapproval. A negative vote. A signal of bad performance.

thumbs up
“Way to go” — An expression of approval, success, or hope.

under (one’s) thumb
Under the control of someone; subordinate to and often refers to excessive domination or manipulation; abuse of power.

‘Your skin is amazing, Vaseline commercial: waterproof barrier, defense against disease, adjusts to surroundings, constantly growing and replacing itself, heals itself, all 800 million cells — do you see skin the way we do?

In zootomy and dermatology, skin is the largest organ of the integumentary system made up of multiple layers of epithelial tissues that guard underlying muscles and organs.  Skin pigmentation (see: human skin color or coloring) varies among populations, and skin type can range from dry skin to oily skin.

The adjective cutaneous literally means “of the skin” (from Latin cutis, skin).
As the interface with the surroundings, skin plays the most important role in protecting (the body) against pathogens. Its other main functions are insulation and temperature regulation, sensation, and synthesis of vitamin D and the protection of vitamin B folate.
Severely damaged skin will try to heal by forming scar tissue, often giving rise to discoloration and depigmentation of the skin.

Skin Layers
Skin is composed of three primary layers: the epidermis, which provides waterproofing and serves as a barrier to infection; the dermis, which serves as a location for the appendages of skin; and the hypodermis (subcutaneous adipose layer).

Epidermis
Epidermis, “epi” coming from the Greek meaning “over” or “upon”, is the outermost layer of the skin. It forms the waterproof, protective wrap over the body’s surface and is made up of stratified squamous epithelium with an underlying basal lamina.

The outermost epidermis consists of stratified squamous epithelium with an underlying connective tissue section, or dermis, and a hypodermis, or basement membrane. The epidermis contains no blood vessels, and cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the dermis. The main type of cells which make up the epidermis are keratinocytes, with melanocytes and Langerhans cells also present. The epidermis can be further subdivided into the following strata (beginning with the outermost layer): corneum, lucidum (only in palms of hands and bottoms of feet), granulosum, spinosum, basale. Cells are formed through mitosis at the basale layer. The daughter cells, (see cell division) move up the strata changing shape and composition as they die due to isolation from their blood source. The cytoplasm is released and the protein keratin is inserted. They eventually reach the corneum and slough off (desquamation). This process is called keratinization and takes place within about 30 days. This keratinized layer of skin is responsible for keeping water in the body and keeping other harmful chemicals and pathogens out, making skin a natural barrier to infection.

Epidermal Components
The epidermis contains no blood vessels, and is nourished by diffusion from the dermis. The main type of cells which make up the epidermis are keratinocytes, melanocytes, Langerhans cells and Merkels cells.

Epidermal Layers
Epidermis is divided into several layers where cells are formed through mitosis at the innermost layers. They move up the strata changing shape and composition as they differentiate and become filled with keratin. They eventually reach the top layer called stratum corneum and become sloughed off, or desquamated. This process is called keratinization and takes place within weeks. The outermost layer of Epidermis consists of 25 to 30 layers of dead cells.

Epidermal Sublayers
Epidermis is divided into the following 5 sublayers or strata:
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum germinativum (also called “stratum basale”)
Mnemonics that are good for remembering the layers of the skin (using “stratum basale” instead of “stratum germinativum”):
“Cher Likes Getting Skin Botoxed” (from superficial to deep)
“Before Signing, Get Legal Counsel” (from deep to superficial)
“Before Sex Get Latex Condoms (from deep to superficial)

Blood capillaries are found beneath the epidermis, and are linked to an arteriole and a venule. Arterial shunt vessels may bypass the network in ears, the nose and fingertips.

Dermis
The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many nerve endings that provide the sense of touch and heat. It contains the hair follicles, sweat glands, sebaceous glands, apocrine glands, lymphatic vessels and blood vessels. The blood vessels in the dermis provide nourishment and waste removal to its own cells as well as the Stratum basale of the epidermis.

Dermal Structure
The dermis is structurally divided into two areas: a superficial area adjacent to the epidermis, called the papillary region, and a deep thicker area known as the reticular region.

Papillary Region
The papillary region is composed of loose areolar connective tissue. It is named for its fingerlike projections called papillae, that extend toward the epidermis. The papillae provide the dermis with a “bumpy” surface that interdigitates with the epidermis, strengthening the connection between the two layers of skin.

In the palms, fingers, soles, and toes, the influence of the papillae projecting into the epidermis forms contours in the skin’s surface. These are called friction ridges, because they help the hand or foot to grasp by increasing friction. Friction ridges occur in patterns (see: fingerprint) that are genetically determined and are therefore unique to the individual, making it possible to use fingerprints or footprints as a means of identification.

The reticular region lies deep in the papillary region and is usually much thicker. It is composed of dense irregular connective tissue, and receives its name from the dense concentration of collagenous, elastic, and reticular fibers that weave throughout it. These protein fibers give the dermis its properties of strength, extensibility, and elasticity.

Also located within the reticular region are the roots of the hair, sebaceous glands, sweat glands, receptors, nails, and blood vessels. Tattoo ink is injected into the dermis. Stretch marks from pregnancy are also located in the dermis.

The hypodermis is not part of the skin, and lies below the dermis. Its purpose is to attach the skin to underlying bone and muscle as well as supplying it with blood vessels and nerves. It consists of loose connective tissue and elastin. The main cell types are fibroblasts, macrophages and adipocytes (the hypodermis contains 50% of body fat). Fat serves as padding and insulation for the body.

Microorganisms like Staphylococcus epidermidis colonize the skin surface. These microorganisms serve as ecoorgan. The density of skin flora depends on region of the skin. The disinfected skin surface gets recolonized from bacteria residing in the deeper areas of the hair follicle, gut and urogenital openings.

Components
The skin is often known as the largest organ of the human body. This applies to exterior surface, as it covers the body, appearing to have the largest surface area of all the organs. Moreover, it applies to weight, as it weighs more than any single internal organ, a
ccounting for about 15 percent of body weight. For the average adult human, the skin has a surface area of between 1.5-2.0 square meters (8-10.8 sq.ft.), most of it is between 2-3 mm (0.10 inch) thick. The average square inch (6 cm