Skin Biology Quiz

The largest organ in the human body, responsible for protecting the internal environment and regulating temperature.

The outermost layer of the skin, composed of epithelial cells arranged in multiple layers.

The deeper layer of the skin, located beneath the epidermis, composed of connective tissue with blood vessels, nerves, and glands.

A layer of loose connective tissue and fat located beneath the dermis, providing insulation and cushioning.

The process of regulating body temperature through the use of blood vessels and sweat glands.

The skin acts as a physical and immune barrier, protecting the body from harmful substances, microbes, and ultraviolet radiation.

The ability of the skin to detect pressure, touch, temperature changes, and pain through specialized sensory receptors.

The skin contributes to excretion by releasing sweat and sebum, and it can absorb some substances through the epidermal layers.

The skin can convert a precursor molecule into vitamin D using ultraviolet radiation from sunlight.

A condition that can be caused by aging and other factors, resulting in changes in the skin's appearance and function.

The process by which keratinocytes in the epidermis differentiate and become flattened, filled with keratin, and eventually shed.

A tough fibrous protein found in skin, hair, and nails, providing structural support and protection.

A specific type of keratin found in the stratum granulosum layer of the epidermis, which helps in the formation of keratin fibers.

A protein found in the stratum lucidum layer of thick skin, acting as an intermediate state of keratin.

A fibrous protein found in the dermis, providing elasticity and allowing the skin to stretch and recoil.

A type of cell found in the dermis, responsible for producing collagen, elastin, and other components of the extracellular matrix.

A complex sugar molecule found in the dermis, acting as a humectant and contributing to skin hydration.

A network of collagen fibers in the dermis, providing structural support and strength to the skin.

The most abundant cell type in the epidermis, responsible for producing keratin, a protein that provides strength and protection to the skin.

Specialized cells in the epidermis that produce melanin, a pigment that gives skin its color and protects against harmful UV radiation.

Immune cells found in the epidermis, playing a role in immune responses by presenting antigens to other immune cells.

Sensory cells found in the epidermis that help detect touch and pressure.

The deepest layer of the epidermis, attached to the dermis. It contains stem cells that continuously produce new keratinocytes.

The thickest layer of the epidermis, composed of several layers of polygonal keratinocytes. It provides strength and flexibility to the skin.

A layer of the epidermis where keratinocytes undergo apoptosis (programmed cell death), and keratinization (the process of becoming tough and waterproof) begins.

A thin, translucent layer of the epidermis present only in thick skin (palms and soles). Cells in this layer contain a protein called eleidin, a precursor to keratin.

The outermost layer of the epidermis, composed of dead, flattened keratinocytes. It acts as a protective barrier against external factors.

The uppermost layer of the dermis, characterized by a loose network of collagen and elastic fibers, forming the dermal papillae which increase surface area.

The deepest layer of the dermis, comprising about 80% of the thickness, containing dense, irregular connective tissue, blood vessels, sensory and sympathetic nerves, and various structures like hair follicles and glands.

A method of drug delivery by applying medication directly to the skin.

A method of drug delivery by injecting medication into the subcutaneous layer.

A method of drug delivery by injecting medication into the muscle.

The primary pigment responsible for determining skin color.

Yellow pigments found in the dermis, contributing to skin coloration.

A protein found in red blood cells, also affecting skin color.

A rarer type of melanin, producing a yellow-red hue to the skin.

A more common melanin, contributing to darker skin tones.

A tumor that arises from melanocytes (pigment-producing cells) in the skin, capable of spreading to other parts of the body.

Visible signs of skin damage caused by prolonged exposure to ultraviolet radiation from the sun.

An excessive reaction of the skin to sunlight, often amplified by certain medications or substances.

Damage to skin tissue caused by heat, electricity, radiation, or chemicals. Characterized by protein denaturation and cell death.

A breakdown of skin tissue caused by prolonged pressure on an area of the body, often affecting bedridden individuals.

A skin lesion characterized by asymmetrical shape, irregular borders, inconsistent color variations, and a diameter greater than 6mm.

The process of converting protein collagen into gelatin in the skin through the application of heat.

The release of histamine from injured cells in the skin, leading to increased blood vessel permeability and inflammation.

Apocrine sweat glands are located in areas like the armpits, groin, areola, and genitals. They produce a thicker, milky or yellowish secretion with fats and proteins. These glands release sweat into hair follicles and become active during puberty.

The ceruminous glands are located in the external auditory canal and produce a substance called cerumen (earwax). They are a combination of sebaceous gland and sweat gland secretions. Earwax, along with ear hair, provides a sticky barrier against foreign objects and insects, and protects the ear canal from water and infections.

Nails are hard, keratinized epidermal cells that form a protective plate over the tips of fingers and toes. They consist of the nail body, free edge, and nail root. They help grip and manipulate small objects, providing protection to the fingertips and toes.

The nail growth rate is around 1 millimeter per week, and it is a continuous process, not cyclical. The pinkish color of nails is due to the tiny capillaries under the nail plate.

Healthy nails are assessed based on their shape, color, thickness, surface, and lunula, revealing their overall health condition.

The majority of age-related skin changes occur in the dermis. This process begins in the 20s and 30s, with a gradual reduction in collagen production, resulting in wrinkles. Elasticity of the skin deteriorates, and fibroblasts decrease in number.

Smoking causes various skin damages through chemicals absorbed through the skin and mucous membranes. It reduces blood circulation, leading to dryness and poor wound healing. Smoking also increases free radical formation, damaging cells and increasing cancer risk. It also impacts collagen breakdown and hair follicle function.

Calcitriol, the active form of vitamin D, is produced by the skin through exposure to sunlight. Calcitriol plays a vital role in calcium metabolism and bone health.

The skin produces hormones like vitamin D, stimulating the production of insulin-like growth factor 1 (IGF-1) and transforming growth factor beta (TGF-beta) which have a role in growth and development.

Skin cancer is a serious condition that occurs when abnormal cells grow uncontrollably, forming tumors. It is commonly caused by excessive sun exposure, but other factors like skin type and genetics also play a role. There are three main types: Basal cell carcinoma, Squamous cell carcinoma, and Melanoma.