Integumentary System

What is the primary function of the integument?

To serve as a covering and the first line of defense against the environment and pathogens.

What percentage of body weight does the integument represent?

7% of body weight.

What are the main components of the integumentary system?

Cutaneous membrane (skin), accessory structures (hair, nails, oil glands, sweat glands), blood and lymphatic vessels, sensory receptors.

What is the fatty layer beneath the skin called?

Subcutaneous layer, which is not technically part of the integumentary system.

What type of epithelium makes up the epidermis?

Stratified squamous epithelium.

What are keratinocytes?

Cells that make up 85% of the epithelial cells in the epidermis and produce keratin.

What is the function of melanocytes?

To synthesize the pigment melanin.

What are dendritic (Langerhans) cells responsible for?

Engulfing foreign substances and activating immune responses.

What do tactile epithelial (Merkel) cells detect?

Light touch sensations.

List the layers of the epidermis.

Stratum corneum, stratum lucidium, stratum granulosum, stratum spinosum, stratum basale.

What mnemonic can help remember the layers of the epidermis?

Come, Let's Get Sun Burned.

What is the stratum basale known for?

Being the deepest epidermal layer with a single row of stem cells that continually divide.

What characterizes the stratum spinosum?

It is known as the prickly layer with several layers of keratinocytes containing pre-keratin.

What occurs in the stratum granulosum?

Keratinization begins, and cells fill with keratin while flattening.

What is the role of lamellar granules in the stratum granulosum?

To secrete a water-resistant glycolipid that slows down water loss.

What is the stratum corneum?

The outermost epidermal layer, 20-30 cells thick, where cells are regularly shed.

What happens to cells in the stratum corneum?

They are shed regularly as part of the skin's renewal process.

What is the primary protein produced by keratinocytes?

Keratin, which provides structure and durability to skin cells.

What type of connections do desmosomes provide?

Strength and flexibility between cells.

What is the function of tight junctions in the epidermis?

To hold cells together tightly and provide a water-tight barrier.

What is the significance of the basal cell division in the stratum basale?

One daughter cell is pushed into the layer above to mature, while the other remains to continue producing new keratinocytes.

How does the structure of the stratum granulosum contribute to skin function?

It contains granules that form keratin and glycolipids that help create a water-resistant barrier.

What is dandruff?

Millions of cells slough off every day from the scalp.

What does 'avascular' mean in relation to the epidermis?

It means that the epidermis has no blood vessels and receives nutrients via diffusion from the dermis.

What are the two layers of the dermis?

The papillary layer (superficial) and the reticular layer (deep).

What is the primary function of collagen in the dermis?

Collagen adds strength and assists in hydrating the skin.

What causes striae (stretch marks)?

Loss of elasticity in the dermis due to overstretching, leading to tearing of collagen and elastin fibers.

What are fibroblasts?

Cells in the dermis that secrete extracellular matrix (ECM) and collagen.

What is melanin and its role in skin color?

Melanin is a pigment produced by melanocytes that determines skin color and protects DNA from UV radiation.

What is the function of carotene in the skin?

Carotene is a yellow to orange pigment consumed in foods that accumulates in the stratum corneum.

What is cyanosis?

A bluish color of the skin often due to low oxygenated hemoglobin.

What are the two types of sweat glands?

Eccrine glands (most abundant) and apocrine glands (found in axillary and anogenital regions).

What is the primary function of sebaceous glands?

To secrete sebum, an oily secretion that softens hair and skin and has bactericidal properties.

What are the three types of skin barriers provided by the skin?

Chemical barriers (antibiotics, melanin), physical barriers (keratinized cells), and biological barriers (immune cells).

What is the role of the hypothalamus in thermoregulation?

It acts as the control center for temperature regulation in the body.

What is basal cell carcinoma?

The most common type of skin cancer, originating from keratinocytes, and is least malignant.

What is melanoma?

A rare but highly metastatic skin cancer originating from melanocytes, responsible for most skin cancer deaths.

What are the characteristics of a second-degree burn?

Involves the epidermis and upper dermis, causing redness, swelling, pain, and blisters.

What are the signs of a third-degree burn?

Involves the entire epidermis and dermis, with grey/white, cherry red, or blackened skin, often requiring skin grafting.

What is the function of nails?

To provide a clear protective covering on the dorsal surface of fingers and toes.

What is the average hair growth rate?

Approximately 2 mm per week.

What is the structure of hair?

Composed of three concentric layers: medulla (soft keratin), cortex (flattened cells), and cuticle (overlapping cells).

What is the purpose of arrector pili muscles?

They contract to cause hair to stand up, resulting in goosebumps.

What is the role of macrophages in the dermis?

They act as immune cells that phagocytize pathogens and debris.

What is the function of vitamin D produced by the skin?

It aids in calcium absorption in the intestine and regulates the cell cycle.

What is the A, B, C, D, E rule for melanoma detection?

Asymmetry, Border irregularity, Color variation, Diameter greater than 6 mm, Evolving size, shape, or color.

What is the significance of the nail matrix?

It is responsible for nail growth and is heavily keratinized.

What is the primary component of sweat?

99% water, along with sodium chloride, organic nutrients, peptides, and waste products.