Skin Structure and Function Quiz

An epithelial layer of ectodermal origin, forming the outermost layer of the skin.

A layer of mesodermal connective tissue beneath the epidermis.

The skin is the largest organ, making up 15-20% of body weight and covering 1.5-2 square meters of surface area.

Another name for the skin, meaning "covering".

The skin helps maintain a stable body temperature by insulating the body and assisting with heat loss (like sweating).

Sensory receptors in the skin that allow for physical interactions with surroundings.

The skin consists of the epidermis (ectoderm) and the dermis (mesoderm), with subcutaneous tissue below the dermis.

The skin has mechanoreceptors that help us feel pressure and touch.

A functional unit of the skin composed of one melanocyte transferring melanosomes to surrounding keratinocytes.

The number of melanocyte units per area of skin is relatively constant across individuals.

Individuals with ancestry near the equator produce melanin more rapidly and abundantly due to higher UV exposure.

Individuals with ancestry in regions with less sunlight have lighter skin to optimize vitamin D3 synthesis from limited UV radiation.

A congenital disorder where tyrosinase or another component of the melanin pathway is defective, resulting in hypopigmentation.

An acquired condition where melanocyte loss or decreased activity causes depigmentation, often in patches.

Tanning is a two-step process involving darkening of existing melanin and increased melanin production due to UV exposure.

Solar radiation at wavelengths of 290 to 320 nm is responsible for tanning.

Small, finger-like projections of the dermis that extend into the epidermis, providing a strong connection between the two layers.

The dermis has two sublayers: the papillary layer (thin, loose connective tissue) and the reticular layer (dense, fibrous connective tissue).

In aging, collagen fibers cross-link extensively, and elastic fibers are lost, making the skin less supple and causing wrinkles.

A condition where excessive sun exposure damages elastic fibers, leading to skin thinning and wrinkles.

These disorders involve defective collagen processing, resulting in excessive skin and ligament extensibility.

With age, the epidermis thins and becomes more transparent, making the skin more delicate.

Sensory nerves in the skin have endings attached to various receptors, allowing for the sensation of touch, pressure, temperature, and pain.

Sweat glands and smooth muscle in the skin are innervated by postganglionic sympathetic nerves, while parasympathetic innervation is absent.

Skin has a remarkable capacity to heal itself after injuries, a vital process for this constantly exposed organ.

The repair process involves multiple overlapping stages: blood clotting, inflammation, tissue formation, and remodeling, lasting longer for larger wounds.

When skin is cut, blood vessels bleed, and the leaked blood clots, forming a plug that stops the bleeding and provides a framework for repair.

White blood cells, called leukocytes, clean the wound by engulfing bacteria and debris, preparing for tissue regeneration.

Fibroblasts are cells that create collagen fibers, forming the connective tissue that strengthens and holds the wound together during healing.

Encapsulated, ovoid structures in the skin of the penis and clitoris, sensitive to low-frequency vibrations. They have thin, collagenous capsules penetrated by a sensory fiber.

Collagenous, fusiform capsules in the skin, firmly anchored to connective tissue. They are sensitive to stretching and twisting.

Invaginations in the epidermis where hair grows, forming elongated keratinized structures.

Hair grows in cycles, with periods of growth (anagen) followed by rest (telogen). This growth is not synchronized throughout the body.

All skin has hair, with varying density. Areas like palms, soles, and lips are hairless. The face has the highest, followed by the rest of the body.

These fibers are distributed throughout the dermis, providing elasticity and flexibility to the skin. They are darker stained and run among the collagen bundles.

The uppermost layer of the dermis, containing fine, smaller elastic fibers that connect to the basement membrane.

A specific staining method that highlights elastic fibers in tissue samples, making them appear darker.

The terminal dilation at the base of a growing hair follicle. It contains a dermal papilla with a capillary network that nourishes the follicle.

The layer of cells surrounding the dermal papilla in the hair bulb, responsible for hair growth.

The visible part of the hair that extends beyond the skin surface.

The process where hair cells produce keratin, a tough protein, to form the hair shaft.

A test that measures the ability to distinguish two closely spaced points on the skin.

Small, oval-shaped mechanoreceptors responsible for light touch and pressure.

A connective tissue disorder that causes hardening and tightening of the skin.