Unit 2: Intro to Integumentary system Week 1

Epidermis definition and function

Definition: Outermost layer of the skin, made of keratinized stratified squamous epithelium

Function:

Dermis definition and function

Definition: Inner, thicker layer of skin beneath the epidermis

Function: Provides strength, elasticity, houses blood vessels, nerves, and skin structures

Hypodermis

Definition: Subcutaneous layer of fat and connective tissue

Function: Insulates, cushions, and stores energy

Keratinocyte definition and function

Definition: Main cell type in epidermis; produces keratin

Function: Strengthens and waterproofs the skin

Melanocyte definition and function

Definition: Pigment-producing cell in the epidermis

Function: Produces melanin for UV protection and skin color

Sebaceous gland definition and function

Definition: Oil gland in dermis that secretes sebum

Function: Lubricates and waterproofs skin and hair

Sudoriferous gland definition and function

Definition: Sweat gland (eccrine & apocrine types)

Function: Helps regulate temperature and excrete waste

Hair follicle definition and function

Definition: Tube-like structure in the dermis from which hair grows

Function: Anchors hair and supports growth

Arrector pili muscle definition and function

Definition: Small smooth muscle attached to hair follicle

Function: Contracts to produce “goosebumps”

Stratum corneum definition and function

Definition: Outermost epidermal layer of dead keratinized cells

Function: Forms a tough, protective outer barrier

Dendritic Cell

(aka: Langerhans cells) definition and function

Definition: specialized immune cells that capture pathogens and present them to other immune cells to initiate a protective immune response.

Function: Immune system "sentinels" that act as Antigen-presenting cells

Tactile Epithelial Cells

(AKA Merkel cells) definition and function

Definition: Present at the epidermal-dermal junction.  Each cell is intimately associated with a disclike sensory nerve ending.

Function: Functions as a sensory receptor for touch

Function of integumentary system

protective covering that shields the body from the external environment and helps maintain internal balance

What are the three main layers of the skin?

1. Epidermis

2. Dermis

3. Hypodermis (Subcutaneous Layer)

What cell types does the epidermis contain?

1. Keratinocytes

2. Melanocytes

3. Langerhans cells

4. Merkel cells

Is the epidermis vascular or avascular?

Avascular- no blood vessels.

How does the epidermis renew its self?

by shedding dead cells and replacing them with new ones.

What structures are in the dermis?

1. blood vessels

2. nerve endings

3. sweat glands

4. sebaceous glands

5. hair follicles

What skin layer is responsible for thermoregulation and how?

Dermis (by adjusting blood flow and sweat production)

What layer of the skin is responsible for sensory reception, allowing us to feel touch, pressure, pain, and temperature.

Dermis

What are the accessory structures of the integumentary system?

1. Hair

2. Nails

3. Sweat Glands

4. Sebaceous (oil) Glands

Hair

1. Made of keratin

2. Helps regulate temp, protect against UV

3. provide sensory input

Nails

1. Composed of hardened keratin

2. protect the tips of fingers and toes

3. 
   

Function of Integumentary system

• Protection – Acts as a physical barrier against pathogens, chemicals, and mechanical injury.

• Temperature Regulation – Maintains body temperature through sweating, vasodilation (widening blood vessels to release heat), and vasoconstriction (narrowing vessels to conserve heat).

• Sensation – Contains sensory receptors for touch, pressure, pain, and temperature.

• Excretion – Removes small amounts of waste products, such as salts and urea, through sweat.

• Vitamin D Production – When exposed to sunlight, the skin synthesizes vitamin D, which is necessary for calcium absorption and healthy bones.

• Water Retention – Prevents excessive fluid loss, maintaining hydration and homeostasis.

What are the layers of the epidermis?

1. Stratum corneum

2. stratum lucidum (Thick skin only)

3. stratum granulosum

4. stratum spinosum

5. stratum basale

What layer of the epidermis undergoes mitosis about every 19 days?

stratum basale

what is the dermis responsible for?

allow the skin to remain strong, flexible, nourished, and responsive to the environment.

What type of tissue is the dermis mainly made of?

connective tissue.

What two layers make up the dermis?

1. Papillary dermis

2. Reticular dermis

what layer of the dermis is the thin, superficial portion?

papillary layer

what percent of the dermis does the papillary make up?

approximately 20% of the dermis.

What is the papillary layer mainly compose of?

Loose areolar connective tissue