Showing posts with label skin. Show all posts
Showing posts with label skin. Show all posts

Wednesday, January 2, 2008

2 - freckle OR ephelid

2 - a flat coloured lesion ( color different from the surrounding skin ) , less than 2 cm in diameter , not raised above the surface of the surrounding skin is called ?

a- macule
b- patch
c- papule
d- nodule

the answer is a- MACULE . a " freckle " or ephelid , is a prototype pigmented macule . other examples of macules are vitiligo and tinea versicolor about which we will know later.

the patch differs from the macule only in size , a patch is a large flat colored lesion ( color different from the surrounding skin ) which is greater than 2 cm in diameter .


the pictures above clearly show u wat freckles are . picture 1 shows Freckled twins. predisposition to freckles is genetic and is related to the presence of the MC1R gene variant.

Freckles are small colored spots of melanin on the exposed skin or membrane of people with complexions fair enough for them to be visible.

Having freckles is genetic and is related to the presence of the melanocortin-1 receptor MC1R gene variant, which is dominant. Freckling can also be triggered by long exposure to sunlight, such as suntanning. When the sun’s rays penetrate the skin, they activate melanocytes which can cause freckles to become darker and more numerous, although the distribution of melanin is not the same. Fair hair such as blonde, or more commonly red hair, are usually common with the genetic factor of freckles, but none so much as fair or pale skin.

Freckles are predominantly found on the face, although they may appear on any skin exposed to the sun. Freckles are rare on infants, and more common on children before puberty; they are less common on adults.

Children who do not produce enough melanin to protect their skin against harmful rays from the sun develop temporary freckles associated with childhood that usually go away upon puberty, once more melanin is produced. People with the fairest skin often do not produce enough melanin, and so freckles are present after puberty and into adulthood, indicating that individual as a genetic carrier for freckles.

Upon exposure to the sun, freckles will reappear if they have been altered with creams or lasers and not protected from the sun, but do however fade with age in some cases. Freckles are not a skin disorder. People with a predisposition to freckles may be especially susceptible to sunburn and skin cancer, and should therefore take extra care to protect themselves in the sun with a daily sunblock of at least SPF 15.
Freckled twins. Predisposition to freckles is genetic and is related to the presence of the MC1R gene variant.
Freckled twins. Predisposition to freckles is genetic and is related to the presence of the MC1R gene variant.

SO WANNA KNOW WAT EPHELIDS ARE ?

Two types of freckles

Ephelides is a genetic trait. It’s used to describe a freckle that is flat, light brown or red, and fades in the winter. Ephelides are more common in those with light complexions and with the regular use of sunblock, can be suppressed.

Liver spots (also known as sun spots) are freckles that do not fade in the winter. Rather, they form after years of exposure to the sun. Lentigines are more common in older people.

1- largest organ in human body

1- which of the following is the largest organ in the human body?

a- liver
b- skin
c- spleen
d- brain

---- answer is b .obviously the answer has to be skin , otherwise y wud i post this question under dermatology . the skin forms approximately 8% of the total body mass . the surface area of the skin in a man weighing 90 kg and with a height of 1.8 m is 2.2 square meters . when we talk about the thickness of the skin it varies depending on the maturation , ageing and regional specifications but generally an average of 1.5 to 4 mm is accepted . gotta accept the values as they are given in GRAY'S ANATOMY 39 TH EDITION - PAGE 157 .

Subscribe Now: Feed

You are visitor number

Visitors currently online