Histology of the Integumentary System

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Questions and Answers

What is the primary function of the integumentary system?

Production of hormones

Protection against environmental insults (correct)

Synthesis of collagen

Regulation of blood pressure

Which layer of the epidermis is primarily responsible for the proliferation of keratinocytes?

Stratum corneum

Stratum basale (correct)

Stratum granulosum

Stratum spinosum

Melanocytes, which produce melanin, are found in which layer of the epidermis?

Stratum basale (correct)

Stratum spinosum

Stratum granulosum

Stratum lucidum

Which characteristic is true of thick skin?

Found on the palmar and plantar surfaces Signup and view all the answers

What type of cells primarily make up the epidermis?

Keratinocytes Signup and view all the answers

What is the role of Langerhans cells in the epidermis?

Function as antigen presenting cells Signup and view all the answers

How does the skin primarily regulate body temperature?

Vasodilation and evaporation of sweat Signup and view all the answers

Which characteristic distinguishes thin skin from thick skin?

Presence of hair follicles Signup and view all the answers

What primarily forms the medulla, cortex, and cuticle of a hair root?

Keratinocytes in the hair bulb Signup and view all the answers

What substance do sebaceous glands secrete onto hair follicles?

Sebum Signup and view all the answers

Which type of sweat gland is responsible for producing sweat that contributes to body cooling?

Eccrine sweat glands Signup and view all the answers

Where are apocrine sweat glands primarily located?

In the axillae and perineum Signup and view all the answers

What is the role of the dermal hair papilla in hair formation?

To supply nutrients and oxygen Signup and view all the answers

What is the primary function of the cutaneous plexus?

To vascularize the hypodermis and deeper portions of the dermis Signup and view all the answers

Which structures contribute to the formation of hair?

Epidermal cells and dermal connective tissue Signup and view all the answers

What is the primary function of Langerhans cells?

Uptake, process, and present antigens to T-lymphocytes Signup and view all the answers

What type of hair is typically present on a fetus?

Lanugo hair Signup and view all the answers

In which layer of the skin are Merkel cells primarily located?

Stratum basale Signup and view all the answers

Where are lymphatic vessels located in relation to the dermal layers?

Below the papillary layer of the dermis Signup and view all the answers

What characterizes the papillary layer of the dermis?

Contains dermal papillae that interdigitate with epidermal pegs Signup and view all the answers

What is the outermost layer of the hair structure called?

Cuticle Signup and view all the answers

Which type of hair replaces lanugo hair after birth?

Vellus hair Signup and view all the answers

Which of the following accurately describes the reticular layer of the dermis?

Predominantly oriented collagen fibers determine skin tension lines Signup and view all the answers

What aspect of the hypodermis is primarily emphasized in its structure?

It functions mainly to insulate and protect deeper structures Signup and view all the answers

What is the role of dermal hair papilla in relation to hair follicles?

It provides nutrients for hair growth Signup and view all the answers

Which of the following statements about skin appendages is true?

All skin appendages are derived from the epidermis. Signup and view all the answers

Why are tattoos considered permanent?

Ink is deposited into the dermis layer Signup and view all the answers

What do dermal papillae primarily contribute to?

Fingerprints and surface texture of the skin Signup and view all the answers

What essential role do macrophages play in the dermis?

Defending against pathogens Signup and view all the answers

What is the primary phase of hair growth during which 90% of hair follicles are active?

Anagen Signup and view all the answers

Which type of sweat gland is characterized by merocrine secretion and is found throughout the body?

Eccrine sweat gland Signup and view all the answers

What is the effect of contraction of arrector pili muscles?

Goosebumps Signup and view all the answers

Which of the following statements about sebaceous glands is true?

They develop from the external root sheath. Signup and view all the answers

In what regions are apocrine sweat glands primarily located?

Axillary and perineal regions Signup and view all the answers

What initiates the functional capability of apocrine sweat glands during puberty?

Hormonal influence Signup and view all the answers

Which phase of hair growth is known for the shedding of hair?

Telogen Signup and view all the answers

What is the role of vasodilation in the skin during heat loss?

Increases sweat production Signup and view all the answers

Study Notes

Overview of the Integumentary System

Composed of skin and derivatives: hairs, sebaceous glands, sweat glands, nails.
Skin consists of two main layers: epidermis and dermis, supported by hypodermis (superficial fascia).
Skin classified as thick (hairless, found on palms and soles) or thin (hairy, covering the rest of the body).
Serves as a protective barrier against UV light, mechanical, chemical, and thermal insults, dehydration, and microorganisms.
Largest sensory organ, equipped with receptors for pain, temperature, touch, and vibration.
Regulates body temperature through sweat evaporation and vasodilation in the dermis.
Vitamin D synthesis occurs in the skin.

Epidermis Structure

A keratinized, stratified squamous epithelium, self-renewing, containing five layers:
- Stratum basale: deepest layer with cuboidal cells, responsible for keratinocyte proliferation; contains melanocytes and Merkel cells.
- Stratum spinosum: several layers of interconnected prickle cells; home to Langerhans cells (APCs).
- Stratum granulosum, Stratum lucidum, Stratum corneum complete the epidermal layers.
Majority of epidermal cells are keratinocytes; non-keratinocytes include melanocytes, Merkel cells, and Langerhans cells.
Lacks blood vessels; nutrients/wastes diffuse from dermis.

Dermis Structure

Composed of dense irregular connective tissue featuring collagen and elastic fibers, divided into:
- Papillary layer: superficial, contains dermal papillae (fingerprint formation) and provides nutrient supply.
- Reticular layer: deeper, orientation of collagen fibers determines skin tension lines (Langer’s lines).

Tattooing Mechanics

Tattoo needles deposit ink into the dermis, specifically within the reticular layer, preventing ink migration.
Deposited ink is encapsulated by immune cells, reducing movement and maintaining tattoo permanence.

Hypodermis Structure

Also known as superficial fascia or subcutis, contains vascular structures.
Houses capillary loops in dermal papillae and cutaneous plexus for dermal and hypodermal vascularization.

Vascularization of Skin

Lymphatic vessels are located below the papillary layer, collecting interstitial fluid and transporting immune cells to lymph nodes.

Hair Structure and Types

Hairs are keratinized structures originating from hair follicles, composed of a central medulla, cortex, and cuticle.
Follicles consist of a bulb (contains dermal papilla) and sheaths derived from epidermis and dermis.
Three hair types: lanugo (fetal hair), vellus (short, fine), and terminal (thicker and darker).
Hair growth has three phases: anagen (growth, 2-7 years), catagen (regression, 2-3 weeks), telogen (resting, 10-12 weeks).

Skin Appendages

Arrector pili muscles: smooth muscles causing hair to stand on end, activated by cold or fear.
Sebaceous glands: secrete sebum for skin and hair protection, associated with hair follicles.
Eccrine sweat glands: secrete watery sweat for thermoregulation, activated by sympathetic fibers.
Apocrine sweat glands: larger glands producing thicker sweat, functional during puberty, localized in axillary and perineal regions.

Summary of Epidermal Appendages

Hair and nails form similarly through keratinocyte proliferation and keratinization.
Sebaceous glands provide sebum; eccrine glands cool the body through sweat evaporation, while apocrine glands contribute to scent and function post-puberty.

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Description

Explore the composition and function of the integumentary system in this quiz. Understand the roles of the skin, hair, nails, and glands, as well as the structure of the epidermis, dermis, and hypodermis. Test your knowledge on how these components work together to protect the body.