model of the skin structure

8/11/2019 Model of the Skin Structure

1/8

MODEL OF THESKIN STRUCTURE


2/8


3/8

THE INTEGUMENTARY SYSTEM

LATEST UPDATE Skin pigment renders sun's UV radiation harmless using projectiles

Date: September 26, 2014

Source:

Lund University

Summary:

The pigment of the skin protects the body from the suns dangerous UV rays, but researchers have not until recently known how this works. Now theyreport that skin pigment converts the UV radiation into heat through a rapid chemical reaction that shoots protons from the molecules of the pigment.

Share This

Researchers at Lund University in Sweden and other institutions have worked out how the pigment of the skin manages to protect the body from thesun's dangerous UV rays. The skin pigment converts the UV radiation into heat through a rapid chemical reaction that shoots protons from the

molecules of the pigment. In a new study, the team from Lund University, working with colleagues in France and Italy, have studied pigment in the skin and its building blocks.

Pigment in both skin and hair comprises two different types of melanin: eumelanin and pheomelanin. Eumelanin makes us develop a suntan and givescolour to brown and black hair, whereas those with red hair and pale skin instead have high levels of pheomelanin.

"We found that eumelanin converts harmful UV radiation into heat with almost 100 per cent efficiency. The chemical reaction is incredibly quick, takingless that a thousandth of a billionth of a second," said Villy Sundstrm, Professor of Chemistry at Lund University.

What happens in detail in the chemical reaction is that a hydrogen ion -- a proton -- is ejected from the pigment at the same moment the UV lightreaches the pigment molecule. The chain of events could be likened to the melanin getting rid of the energy of the UV light by very quickly shooting aproton projectile. This projectile in turn gives off energy to the surrounding membrane tissue in the form of heat. It has therefore converted dangerousUV energy into harmless heat.

"In this way, the pigment disarms the energy in the UV light and prevents it causing harmful chemical reactions," said Villy Sundstrm.

Eumelanin is considered to be the pigment that protects against UV radiation while pheomelanin is believed to cause skin cancer in some way, whichexplains why people with red hair are more likely to develop malignant melanoma. However, researchers have not previously been aware of what

chemical reactions UV light causes in the pigment. There has therefore also been a lack of knowledge of the pigment processes that lead to protectionagainst or development of cancer.

"By understanding how the body naturally protects itself against UV light, we can develop better sun protection products based on the same principles.This would provide better protection against skin cancer," said Villy Sundstrm.

The idea is also in the long run to find treatment methods and substances that replace natural pigment for those with defective production ofeumelanin. Eumelanin is composed of two similar building blocks, but only one of them produces the protective effect. This shows that the effect is veryspecific -- it is a matter of small differences in the chemical structure of the building blocks. This insight could prove important in the development ofsubstances for treatment and sun protection products.


4/8

VITILIGO TREATMENT HOLDS PROMISE FOR RESTORING

SKIN PIGMENTATION

September 17, 2014

Source:

Henry Ford Health System

Summary:

A treatment regimen is safe and effective for restoring skin pigmentation in vitiligo patients, according to a study. Our findings offer patients with vitiligo worldwide a renewed hope for a brightfuture in the treatment of this disfiguring disease, says the studys lead author. Patients with lesions on their face and arms could have a more rapid response to the combination treatment.

Effects of the combination treatment on skin repigmentation, from top to bottom, at baseline, at 66 days and at 140 days of the study.

Credit: Image courtesy of Henry Ford Health System

[Click to enlarge image]

A treatment regimen is safe and effective for restoring skin pigmentation in vitiligo patients, according to a Henry Ford Hospital study.

"Our findings offer patients with vitiligo worldwide a renewed hope fo r a bright future in the treatment of this disfiguring disease," says Henry Lim, M.D., chair of Dermatology at Henry Ford andthe study's lead author. "Patients with lesions on their face and arms could have a more rapid response to the combination treatment."

Henry Ford dermatologists described the repigmentation results as "superior," and said the treatment combination holds promise as a future therapy for the more than 50 million peopleworldwide living with vitiligo. It affects about one in every 100 people in the United States.

The study will be published online in the Journal of the American Medical Association-Dermatology. In a multi-center study led by Henry Ford, dermatologists sought to evaluate the safety and effectiveness of a treatment combination of afamelanotide, a drug that induces skin pigmentation, and

phototherapy using narrowband ultraviolet-B rays (NB UVB). Phototherapy, or ultraviolet light therapy, is the treatment of choice for many patients with widespread vitiligo. It has been shown tobe effective, though the degree of repigmentation varies.

Dr. Lim, an international vitiligo expert, says afamelanotide "enhances the ability of the UVB to induce repigmentation of the skin."

Patients were randomly divided into two study groups: Group A received the combination therapy; Group B received only NB UVB treatment.

Key findings:

Repigmentation occurred faster in patients who received the combination treatment compared to patients who received NB UVB.

Patients who received the combination treatment achieved appearance of pigment on their face and arms after 40 days compared to 60 days for patients who received NB UVB.

In dark-skinned patients, repigmentation occurred faster in the combination group compared to the NB UVB group.

Afamelanotide is in the process of being submitted for approval fro m the U.S. Food and Drug Administration for use in treating vitiligo.

Vitiligo is a skin disease that causes the skin to lose color and develop white patches that vary in size and location. It develops when cells called melanocytes are killed by the body's immunesystem, causing the area of skin to turn white because the cells no longer make pigment. Vitiligo is more noticeable in individuals with darker skin tones, but it affects all races and ethnicities.

While vitiligo is neither contagious nor life-threatening, there is no cure. However, it causes low self-esteem and depression for those living with the disease.

The Henry Ford study represents its latest research into investigating new treatment options for vitiligo. In a 2012 study published in the Journal of the American Academy of Dermatology, HenryFord dermatologists showed the benefits of skin cell transplant surgery, called melanocyte-keratinocyte transplantation or MKTP. Henry Ford has since performed more than 190 MKTP

procedures on patients from Michigan, 23 other U.S. states and Canada. For this new study, 55 patients were enrolled at four sites -- Henry Ford, Icahn School of Medicine at Mount Sinai in New York and Vitiligo and Pigmentation Institute of Southern California and

University of California Davis' Department of Dermatology.

In the two study groups, 28 patients were enrolled in Group A and 27 patients in Group B. Both groups received phototherapy two to three times a week for six months for a total of 72treatments. In addition to phototherapy, patients in Group A received a dose of 16 mg of afamelanotide in four monthly treatments. Afamelanotide, about the size of a grain of rice, wasimplanted just under the skin.

Two common vitiligo assessment scoring systems -- Vitiligo Area Scoring Index and Vitiligo European Task Force -- were used to evaluate the repigmentation response.

While patients in both groups showed repigmentation, the response in Group A was superior to Group B by the 56th day of treatment and even better by the 168th day of treatment. The mostcommon side effect was redness of the skin.


5/8

MODEL OF THESKELETAL SYSTEMThe human skeleton is the internal framework of the body. It is composed of 270 bones at birth[1][2][3] this total decreases to 206 bones by adulthood after some boneshave fused together. The bone mass in the skeleton reaches maximum density around age 30. The human skeleton can be divided into the axial skeleton and the

appendicular skeleton. The axial skeleton is formed by the vertebral column, the rib cage and the skull. The appendicular skeleton, which is attached to the axial skeleton, isformed by the pectoral girdles, the pelvic girdle and the bones of the upper and lower limbs.

The human skeleton serves six major functions; support, movement, protection, production of blood cells, storage of ions and endocrine regulation.

The human skeleton is not as sexually dimorphic as that of many other primate species, but subtle differences between sexes in the morphology of the skull, dentition, longbones, and pelves exist. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within a given population. The pelvis infemale skeletons is also different from that of males in order to facilitate child birth.


6/8


7/8

Updates on the Skeletal System

Definition

By Mayo Clinic Staff

OsteoporosisInsightOsteoporosis causes bones to become weak and brittle so brittle that a fall or even mild stresses likebending over or coughing can cause a fracture. Osteoporosis-related fractures most commonly occur inthe hip, wrist or spine.

Bone is living tissue, which is constantly being absorbed and replaced. Osteoporosis occurs when thecreation of new bone doesn't keep up with the removal of old bone.

Osteoporosis affects men and women of all races. But white and Asian women especially those whoare past menopause are at highest risk. Medications, healthy diet and weight-bearing exercise canhelp prevent bone loss or strengthen already weak bones.

SYMPTOMS

There typically are no symptoms in the early stages of bone loss. But once bones have been weakenedby osteoporosis, you may have signs and symptoms that include:

Back pain, caused by a fractured or collapsed vertebra

Loss of height over time

A stooped posture

A bone fracture that occurs much more easily than expected

When to see a doctor

You may want to talk to your doctor about osteoporosis if you went through early menopause, tookcorticosteroids for several months at a time or have a family history of hip fractures.


8/8

Causes

By Mayo Clinic Staff

Your bones are in a constant state of renewal

new bone is made and old bone is broken

down. When you're young, your body makes

new bone faster than it breaks down old bone

and your bone mass increases. Most people

reach their peak bone mass by their early 20s.

As people age, bone mass is lost faster than it's

created.

How likely you are to develop osteoporosis

depends partly on how much bone mass you

attained in your youth. The higher your peak

bone mass, the more bone you have "in the

bank" and the less likely you are to developosteoporosis as you age.

model of the skin structure

Documents