Skin Functions and Burns Effects

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Questions and Answers

What is the primary function of the skin in relation to thermoregulation?

To facilitate evaporative cooling (correct)

To provide sensory perception

To retain body heat

To synthesize vitamin D

Which effect does a full-thickness burn have on fluid loss through the skin?

Fluid loss increases up to five times normal levels (correct)

Fluid loss is halted entirely

Fluid loss decreases significantly

Fluid loss remains normal

What condition is often a leading cause of death in individuals with severe burns?

Hypoxia

Dehydration

Hypothermia

Sepsis (correct)

Which of the following is NOT a function of hair?

Fluid absorption Signup and view all the answers

What change occurs in the skin as a result of aging that affects its protective functions?

Thinning of the epidermis Signup and view all the answers

Which structure of the skin is responsible for sensing danger?

Dermal receptors Signup and view all the answers

Which layer of skin is primarily affected by a burn, resulting in compromised restoration of fluid balance?

Epidermis Signup and view all the answers

Which component of nails is responsible for growth?

Nail root matrix Signup and view all the answers

What primarily composes the reticular layer of the dermis?

Dense irregular connective tissue Signup and view all the answers

Which gland type is primarily involved in thermoregulation?

Eccrine (merocrine) sweat glands Signup and view all the answers

What pigment gives skin its brownish tones and varies among individuals?

Melanin Signup and view all the answers

What can excessive UV light exposure lead to in terms of skin damage?

Solar elastosis Signup and view all the answers

Which type of sweat gland becomes functional at puberty?

Apocrine sweat glands Signup and view all the answers

What is the primary function of sebaceous glands?

Oily secretion to soften hair and skin Signup and view all the answers

What causes the skin of a fair-skinned person to appear red during exercise in hot weather?

Vasodilation of capillaries Signup and view all the answers

What structure in the skin is primarily responsible for appendages such as hair and nails?

Epidermis Signup and view all the answers

What is the primary function of fibroblasts located in the dermis?

Produce collagen and elastin fibers Signup and view all the answers

Which layer of the epidermis contains only dead, flat, keratinized cells?

Stratum corneum Signup and view all the answers

What type of cells are responsible for producing melanin in the skin?

Melanocytes Signup and view all the answers

What is a primary function of sweat glands in the skin?

Regulate temperature by evaporative cooling Signup and view all the answers

How does the stratum basale contribute to skin regeneration?

By containing stem cells that can divide Signup and view all the answers

What layer of skin primarily contains oil and sweat glands?

Reticular layer of the dermis Signup and view all the answers

Which characteristic of the stratum corneum is vital for preventing microbial growth on the skin?

Thickness and keratinization Signup and view all the answers

How does a severe burn affect the skin's barrier function?

Compromises the barrier, increasing infection risk Signup and view all the answers

Study Notes

Skin Functions Affected by Burns

Burns affect fluid and electrolyte balance, with partial-thickness burns hindering barrier function and full-thickness burns increasing fluid loss fivefold.
Thermoregulation is disrupted due to increased evaporative cooling from fluid loss.
Burns compromise protection from infection, with dampness and broken skin promoting bacterial growth.
Sepsis (widespread bacterial infection) is a leading cause of death among burn victims.

Function of the Skin

The skin's primary function is to act as a barrier, protecting the body's internal environment.
It retains body heat and water, repels external threats like water, bacteria, and chemicals.
The skin regulates body temperature, senses danger, protects against force, and synthesizes vitamin D.

Temperature Regulation

Blood vessel dilation delivers warm blood to the body surface for cooling.

Hair Structure

Hair consists of a shaft (superficial portion) and a root (below the surface).
The cuticle forms the outermost layer of hair.
Hair develops within follicles, downward extensions of the epidermis.

Functions of Hair

Hair provides protection, contributes to thermoregulation, serves sensory purposes, and has a minor role in humans.

Growth of Hair

The hair papilla, located at the base of the follicle, contains blood vessels and nerves, nourishing the hair.
The bulb contains the matrix, epithelial cells responsible for hair growth, including melanocytes.

Arrector Pili

This smooth muscle attaches to the hair follicle, raising the hairs.
It responds to fright or cold.
Its function is to create goosebumps.

Nail Structure

Nails consist of the nail body, free edge, and nail root.
The matrix is responsible for nail growth.
The lunula (moon) is the visible part of the nail matrix.

Effects of Aging on the Skin

Aging results in fewer melanocytes, a drier and thinner epidermis, a diminished immune response, a thinner dermis, decreased perspiration, altered hair and fat distribution, fewer active follicles, slower skin repair, and a reduced blood supply.

Dermis

The dermis is the strong, flexible connective tissue beneath the epidermis.
It contains collagen fibers, elastin fibers, fibroblasts, macrophages, mast cells, nerves, blood vessels, lymphatic vessels, and sweat glands.
It is composed of two layers: the papillary layer and the reticular layer.

Papillary Layer

The papillary layer is loose connective tissue with projections called dermal papillae.
It is composed of collagen fibers.
It contains capillaries, touch receptors (Meissner’s corpuscles), and pain receptors.
Dermal ridges (epidermal ridges) create patterns known as fingerprints.

Reticular Layer

The reticular layer is dense irregular connective tissue, composing about 80% of the dermis' thickness.
Collagen fibers provide strength and resilience.
It holds water.
Dermal tearing causes stretch marks.

Skin Color

Skin color is primarily attributed to melanin, hemoglobin, and carotene.
Race is determined by melanin levels, not the number of melanocytes.

Melanocytes and Pigmentation

Melanocytes produce melanin, a pigment that influences skin color.
Local melanin accumulation results in freckles and pigmented moles.
Tyrosinase in melanocytes interacts with melanin production.
UV light stimulates melanin production, but excessive exposure can damage DNA and cause solar elastosis.
Carotene, derived from vitamin A, deposits in the stratum corneum, giving the skin an orange tone.

Appendages of the Skin

These are derivatives of the epidermis, including sweat glands, oil glands, hair follicles, and nails.

Sweat Glands

Eccrine (merocrine) sweat glands, found on palms, soles, and forehead, secrete sweat composed of water, salt, vitamin C, antibodies, dermcidin, and metabolic wastes.
Their ducts connect to pores and function in thermoregulation.
Apocrine sweat glands, located in axillary and anogenital areas, secrete sebum (sweat with fatty substances and protein).
Their ducts connect to hair follicles and become functional during puberty.

Specialized Apocrine Glands

Ceruminous glands, located in the external ear canal, secrete earwax (cerumen).
Mammary glands are specialized apocrine glands.

Sebaceous Glands

Sebaceous glands are widely distributed and develop from hair follicles.
They become active at puberty.
They secrete sebum, an oily holocrine secretion that is bactericidal and softens hair and skin.

Epidermis

The epidermis is the outermost layer of the skin, composed of epithelial cells.
It rests on a basement membrane.
It is composed of five layers: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.

Cells of the Epidermis

Keratinocytes produce keratin, a fibrous protein.
Melanocytes produce melanin and constitute 10-25% of cells in the lower epidermis.
Epidermal dendritic (Langerhans) cells are macrophages that activate the immune system.
Tactile (Merkel) cells are touch receptors.

Stratum Basale (Basal Layer)

The stratum basale rests on the basement membrane and is composed of a single row of stem cells.
It contains melanocytes.

Stratum Spinosum (Prickly Layer)

The stratum spinosum is composed of cuboidal cells joined by desmosomes.
As these cells push to the surface, they acquire keratin and become keratinocytes.

Stratum Granulosum (Granular Layer)

The stratum granulosum contains keratinocytes that produce keratin granules.
It also contains lamellar granules, which release waterproofing glycolipids.

Stratum Lucidum (Clear Layer)

The stratum lucidum is found only in thick skin, like the palms of the hands and soles of the feet.
It is composed of dead keratinocytes.

Stratum Corneum (Horny Layer)

The stratum corneum is composed of 20-30 rows of dead, flat, keratinized squamous cells.
It is waterproof, repels environmental agents, and does not support microbial growth.
It sheds cells, carrying away microbes and hazards.

Structures in the Dermis

The dermis contains fibroblasts, macrophages, dendritic cells, precapillary sphincters, and nerves.

The Anatomy of Skin and Associated Structures

Skin is the largest human organ.
The epidermis is 0.1 mm thick.
Numerous structures are embedded in the skin's tissue layers, including blood vessels, nerves, mechanoreceptors, sweat glands, hair follicles, and oil glands.
Skin is composed of two layers: the epidermis and dermis.

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Description

Explore the critical functions of the skin and how burns can disrupt these essential processes. This quiz highlights the impact of burns on fluid balance, thermoregulation, and infection risk. Test your knowledge on skin structure, temperature regulation, and the protective functions of the skin.