The Integumentary System - CH 5

Flashcards covering key concepts from the Integumentary System lecture notes (CH 5).

Define the protective chemical barrier of the integumentary system.

The chemical barrier consists of low pH secretions (acid mantle) and defensins.

What is the function of the chemical barrier in the integumentary system?

It slows bacterial activity.

Define the protective physical/mechanical barrier of the integumentary system.

The physical/mechanical barrier is constituted by keratin and glycolipids.

What is the function of the physical/mechanical barrier in the integumentary system?

It blocks water and limits penetration by lipid-soluble substances.

Define the protective biological barrier of the integumentary system.

The biological barrier is made up of dendritic cells and macrophages.

What is the function of the biological barrier in the integumentary system?

Dendritic cells and macrophages provide immune defense against pathogens.

How much insensible perspiration occurs daily under normal conditions?

Approximately 500 ml of insensible perspiration occurs daily.

What is the function of insensible perspiration?

It is a continuous, unperceivable loss of water from the skin, contributing to fluid balance and minimal cooling.

What are the physiological responses when body temperature rises?

When temperature rises, there is dilation of dermal vessels and increased sweat gland activity (sensible perspiration).

What is the collective function of these responses when body temperature rises?

These responses work to cool the body down.

What are the sensory modalities detected by the integument?

The integument detects temperature, touch, and pain.

What is the function of the integumentary system regarding sensory modalities?

It serves as a sensory organ, allowing the body to perceive its external environment.

Describe the metabolic function of the skin related to vitamin D.

The skin synthesizes vitamin D (cholecalciferol, vitamin D3) via sunlight acting on 7-dehydrocholesterol.

What is the purpose of the skin's metabolic function in vitamin D synthesis?

It is the initial step in producing active vitamin D, crucial for calcium balance in the body after further conversions in the liver and kidneys.

What is the sequence of vitamin D activation starting from its production in the skin?

The skin produces vitamin D3; the liver converts it to 25-hydroxyvitamin D3; the kidney converts it to 1,25-dihydroxyvitamin D3.

What is the ultimate function of active vitamin D (1,25-dihydroxyvitamin D3) in the body?

Its role is to maintain calcium balance.

Name the three major regions of the skin.

The three major regions are the epidermis, dermis, and hypodermis (subcutaneous layer).

What is the general function of these three major regions of the skin?

They collectively form the protective barrier of the body, providing various functions like sensation, thermoregulation, and metabolic activities, with the hypodermis primarily serving for fat storage and insulation.

What are the two layers that constitute the dermis?

The two layers of the dermis are the papillary layer and the reticular layer.

What is the collective function of the dermis layers?

They provide strength, elasticity, and flexibility to the skin, house accessory structures, and contain blood vessels and nerve endings.

List the epidermal layers from superficial to deep.

The epidermal layers are Stratum corneum, Stratum lucidum (thick skin only), Stratum granulosum, Stratum spinosum, and Stratum basale.

What is the overall function of the epidermal layers?

These layers provide the primary barrier function of the skin, protecting against pathogens, UV radiation, and water loss, while also allowing for sensory perception and housing melanocytes.

Which epidermal layer is the deepest and contains actively mitotic stem cells?

The Stratum basale is the deepest epidermal layer and contains actively mitotic stem cells.

What is the function of the Stratum basale?

It is responsible for generating new keratinocytes, ensuring continuous renewal of the epidermis.

Which epidermal layer contains keratohyalin granules and lamellated granules?

The Stratum granulosum contains keratohyalin granules and lamellated granules.

What is the function of the Stratum granulosum's granules?

Keratohyalin granules help form keratin, and lamellated granules release water-resistant glycolipids, contributing to the skin's barrier function.

Define the stratum corneum.

The stratum corneum is the most superficial layer, consisting of 20–30 layers of dead, keratin-filled cells.

What is the function of the stratum corneum?

It provides a tough, protective, and water-resistant outer barrier for the skin.

What is melanin?

Melanin is a pigment produced by melanocytes.

What is melanin's function in the skin?

It serves as pigment shields for nuclei, protecting them from UV radiation, and is transferred from melanocytes to keratinocytes.

What are the pigments that contribute to skin color?

Melanin, carotene, and hemoglobin are the pigments that contribute to skin color.

What is the overall function of these pigments in skin color?

They collectively determine the wide range of human skin tones and provide protective functions, particularly melanin against UV radiation.

How is melanin transferred between cells in the skin?

Melanosomes are produced in melanocytes, move into melanocyte processes, and keratinocytes phagocytize the tips of these processes to take in melanosomes.

What is the function of this melanin transfer process?

This process ensures that keratinocytes are supplied with melanin to form protective pigment shields for their nuclei against UV radiation.

Identify the two layers of the dermis by location.

The two layers of the dermis are the Papillary layer (superficial) and the Reticular layer (deeper).

What is the general function served by the two layers of the dermis?

Together, they provide the skin with its strength, elasticity, and flexibility, housing blood vessels, nerves, and other accessory structures.