The pigment responsible for skin tanning is?

Appeared in: IGNOU PB Bsc Nsg Entrance-2017

Explanation

Melanin is a brown-black pigment produced by specialized cells called melanocytes located in the basal layer of the epidermis.
Exposure to ultraviolet (UV) radiation from the sun stimulates melanocytes to increase the production and secretion of melanin.
This process, known as melanogenesis, causes the skin to darken (tan) as a protective response to shield cellular DNA from UV damage.
Melanin absorbs the vast majority of UV radiation, preventing it from penetrating deeper into the skin and causing harm.

Option A: Carotene is a yellow-orange pigment obtained from dietary sources like carrots and sweet potatoes. While it can accumulate in the skin and contribute to its overall color, it is not produced in response to sun exposure and does not cause tanning.
Option B: Red blood cells contain hemoglobin, a protein that binds oxygen and gives blood its red color. The presence of blood in dermal capillaries gives the skin a pinkish hue, but it is not a pigment involved in the tanning process.
Option D: Sebum is an oily, waxy substance secreted by sebaceous glands. Its function is to lubricate and waterproof the skin and hair. It is colorless and plays no role in pigmentation or tanning.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Physiology of skin pigmentation and tanning as background academic context rather than a clinical decision trigger.
Understanding that tanning is a sign of skin damage is crucial for patient education. Nurses must advise on sun safety, including the use of broad-spectrum sunscreen, to reduce the risk of skin cancers like melanoma.
A person's ability to tan is related to their skin phototype (e.g., Fitzpatrick scale). Individuals with fair skin have less protective melanin and are at a much higher risk for sunburn and skin cancer.
What if? A patient with albinism has a genetic inability to produce melanin. They cannot tan at all and are extremely susceptible to UV damage. Nursing care for these patients involves strict counseling on sun avoidance and protection.

How to Approach the Question

First, identify the key concepts in the question: 'pigment' and 'skin tanning'.
Recall the definition of tanning: the darkening of the skin as a physiological response to sun (UV) exposure.
Evaluate each option's biological function in the skin.
Carotene is a dietary pigment, not a response to sun.
Red blood cells provide color from blood flow, not tanning.
Sebum is an oil for lubrication, not a pigment.

Concept Tested & Keywords

QZzFYReixQm46bEK5Wd0DU

E6 Pathology-Textbook of PATHOLOGYHarsh Mohan Part 1 (1-214) p. 85-87

E6 Medicine Harrison 22e Part 1 p. 471-473

Practise the full IGNOU PB Bsc Nsg Entrance-2017

Attempt every question from this paper in a timed mock, then review the full solution for each one.