Skin Biology Quiz: Melanin and Epidermis

Eumelanin (brownish black) and pheomelanin (reddish yellow).

In darker-skinned individuals, melanin granules are more spread out throughout the keratinocytes. In lighter-skinned individuals, melanin is clumped near the keratinocyte nucleus.

UV light stimulates melanocytes to secrete melanin, which darkens the skin. This color fades as melanin is degraded and old cells are exfoliated.

<p>Haemoglobin (from red blood cells) and carotene (from egg yolks and yellow/orange vegetables).</p> Signup and view all the answers

<p>Cyanosis is blueness due to oxygen deficiency in the blood. Albinism is pale skin and blue-gray eyes due to a genetic lack of the melanin synthesizing enzyme.</p> Signup and view all the answers

<p>Keratin; it makes the layer tough and resistant to abrasion and water loss.</p> Signup and view all the answers

<p>Stratum spinosum; the preparation process causes the cells to shrink but remain connected at desmosomes.</p> Signup and view all the answers

<p>Stem cells/keratinocytes and melanocytes.</p> Signup and view all the answers

<p>Hypodermis</p> Signup and view all the answers

<p>Keratinized stratified squamous epithelium.</p> Signup and view all the answers

<p>Stratum lucidum</p> Signup and view all the answers

<p>They divide and form keratinocytes that migrate to the skin surface to replace lost cells.</p> Signup and view all the answers

<p>Epidermis, dermis and hypodermis.</p> Signup and view all the answers

<p>Diffusion from the underlying connective tissue in the dermis.</p> Signup and view all the answers

<p>Resists abrasion, penetration, and water loss due to its multiple layers of dead, scaly, keratinized cells.</p> Signup and view all the answers

<p>Tactile cells</p> Signup and view all the answers

<p>Dense irregular connective tissue</p> Signup and view all the answers

<p>Dermal papillae</p> Signup and view all the answers

<p>Ichthyosis</p> Signup and view all the answers

<p>Hypodermis</p> Signup and view all the answers

<p>Melanocytes</p> Signup and view all the answers

<p>Dendritic cells</p> Signup and view all the answers

<p>Striae</p> Signup and view all the answers

<p>Stratum basale</p> Signup and view all the answers

<p>Hypodermis</p> Signup and view all the answers

<p>Bleeding into the cut.</p> Signup and view all the answers

<p>Dilates blood vessels and increases capillary permeability.</p> Signup and view all the answers

<p>Blood plasma carries antibodies and clotting proteins into the wounded area.</p> Signup and view all the answers

<p>Knitting the edges of the cut together, inhibiting pathogen spread and forming a scab.</p> Signup and view all the answers

<p>Temporarily seals the wound and blocks infection.</p> Signup and view all the answers

<p>Macrophages</p> Signup and view all the answers

<p>Mast cells and damaged cells</p> Signup and view all the answers

<p>By inhibiting the spread of pathogens.</p> Signup and view all the answers

<p>Humans sacrifice perfect, scar-free regeneration for speed of healing to prevent infection and wound breakdown.</p> Signup and view all the answers

<p>The ability to achieve complete regeneration of skin tissue without scarring.</p> Signup and view all the answers

<p>Approximately 100 million patients annually, caused by elective operations and trauma.</p> Signup and view all the answers

<p>Approximately 4 million.</p> Signup and view all the answers

<p>Increased pigmentation.</p> Signup and view all the answers

<p>Apocrine sweat glands.</p> Signup and view all the answers

<p>Bromhidrosis.</p> Signup and view all the answers

<p>Inhibiting bacterial growth; the acid mantle.</p> Signup and view all the answers

<p>Proteins.</p> Signup and view all the answers

<p>Insensible perspiration.</p> Signup and view all the answers

<p>Sebum; keeps skin and hair from becoming dry, brittle, and cracked.</p> Signup and view all the answers

<p>Holocrine secretion.</p> Signup and view all the answers

<p>Apocrine sweat glands.</p> Signup and view all the answers

<p>Polythelia.</p> Signup and view all the answers

<p>UV rays from the sun.</p> Signup and view all the answers

<p>Stratum basale.</p> Signup and view all the answers

<p>Keratinocytes of the stratum spinosum.</p> Signup and view all the answers

<p>Thin hair.</p> Signup and view all the answers

<p>Growth zone (mitotic) of stratum basale; at proximal end of nail.</p> Signup and view all the answers

<p>Contract to squeeze perspiration up the duct.</p> Signup and view all the answers

A pigment produced by melanocytes affecting skin color.

A form of melanin that is brownish-black in color.

A type of melanin with a reddish-yellow hue, containing sulfur.

UV light exposure stimulates melanin production, darkening the skin.

A bluish color of the skin due to oxygen deficiency in blood.

The organ system that includes skin, hair, nails, and glands.

The outermost layer of skin, made of stratified squamous epithelium.

The main cell type in the epidermis that produces keratin.

The deepest layer of the epidermis containing stem cells and keratinocytes.

The layer of the epidermis with several keratinocyte layers joined by desmosomes.

A layer of flat keratinocytes containing keratohyalin granules.

A thin, pale layer of the epidermis found only in thick skin.

The outermost layer of skin composed of dead, keratinized cells.

The deep connective tissue layer below the dermis, not part of the skin.

Glands that produce sweat; two types are eccrine and apocrine.

Undifferentiated cells in stratum basale that produce keratinocytes.

Cells in the stratum basale that produce melanin, protecting DNA from UV radiation.

Macrophages originating in bone marrow, guarding against pathogens in skin layers.

Touch receptor cells in the basal layer of the epidermis associated with nerve fibers.

Inherited skin disorder inhibiting cell shedding, leading to a buildup of dead skin.

Chronic inflammatory skin condition characterized by dry, itching, and reddened areas.

Connective tissue layer beneath the epidermis, rich in blood vessels and glands.

Superficial region of dermis made of thin areolar tissue, allowing cell mobility.

The normal outcome of mammalian tissue repair, occurring frequently in humans after injuries or surgeries.

Planned surgeries performed on patients, contributing to the majority of scars acquired annually.

Raised scars that form after an injury, often occurring in individuals with darker skin tones.

The body's quick biological reaction that helps to heal wounds and prevents infections.

Complete healing without scarring seen in animals like salamanders and some invertebrates.

Initial response where severed vessels bleed into the cut, facilitating healing.

Mast cells and damaged cells release histamine to aid in healing.

Histamine causes blood vessels to dilate, increasing blood flow to the wound.

Histamine increases capillary permeability, allowing plasma to seep into the wound.

Blood clot forms at the wound site, helping to knit edges together and block pathogens.

A scab forms to temporarily seal the wound and protect against infection.

Macrophages digest tissue debris, cleaning the wound area.

Blood plasma carries antibodies to fight infection during healing.

Skin protects, regulates temperature, and provides sensation.

Structure in skin from which hair grows; contains living cells.

Hair is divided into bulb, root, and shaft.

Condition of hair thinning or baldness.

A protein that makes up hair and nails, providing strength.

Two types: apocrine and merocrine, each with different functions.

Sweat glands located in armpits and groin, active at puberty.

Most numerous sweat glands, produce watery sweat for cooling.

Glands that secrete oil (sebum) to hydrate skin and hair.

Growth zone of the nail located at the proximal end.

Includes basal cell carcinoma, squamous cell carcinoma, and malignant melanoma.

Most common type of skin cancer, rarely spreads, forms shiny bumps.

Skin cancer from keratinocytes; can metastasize if untreated.