Topic 3: Integumentary System

Functions of the Integumentary System

• Protection

• Regulation of body temperature

• Excretion

• Provides sensory information

• Synthesis of vitamin D3 and lipid reserves

• Coordinates immune responses of the skin

Divisions of the Integumentary System: Superficial to deepest

• Epidermis

• Dermis

• Hypodermis

What is the surface layer of skin?

Epidermis

Which layer of skin contains blood vessels and nerves?

Dermis

Which layer of the skin contains subcutaneous fat?

Hypodermis

Which layer of the skin contains superficial fascia which separates skin layers from organs?

Hypodermis

Which type of skin contains 5 layers?

• Thick skin

  • Palms of hands

  • Soles of feet

Layers of the skin (Deepest to most superficial)

• Stratum germinativum

• Stratum spinosum

• Stratum granulosum

• Stratum lucidum

• Stratum corneum

Which layer of skin is only found in thick skin?

Stratum lucidum

Which layer of the skin contains stem cells, capable of regeneration?

Stratum germinativum

In what layer of skin are calluses formed? Highly concentrated in protein filaments?

Stratum spinosum

What layer of skin is keratinized?

Stratum granulosum

What layer of skin has 15-30 layers of flat, dead cells?

Stratum corneum

Main cell type in integumentary system

Keratinocyte

What cell type is a keratinocyte?

Stratified squamous epithelium

Accessory Structures of the skin

• Hair follicles

• Sweat glands

• Nails

Melanocytes produce:

Melanin

Function of melanin

Prevent skin damage by absorbing UV radiation

UV exposure causes melanocytes to…

Increase melanin synthesis and transfer

What gives you fingerprints?

• Dermal papilla

• Epidermal ridges

Epidermal ridges extend from the ___ layer into the ____ layer

Dermis into epidermis

What are the 2 layers of the dermis?

• Papillary layer

• Reticular layer

Where is the papillary layer located?

Directly under epidermis

The papillary layer of dermis consists of which type of CT?

Loose CT Proper

The papillary layer of dermis contains?

• Capillaries

• Nerve endings

• Sensory apparatus

Where is the reticular layer located?

Under the papillary layer

The reticular layer of dermis consists of which type of CT?

Dense irregular CT proper

The reticular layer of dermis contains?

• Blood vessels

• Hair follicles

• Nerves

• Sweat glands

• Sebaceous glands

• Collagen fibers

What extends from the reticular layer into the papillary layer to link the two layers?

Collagen fibers

The hypodermis consists of what type of tissue?

Loose CT proper

Functions of the hypodermis

• Store energy using adipose tissue

• Helps stabilize skin position from underlying tissues

Hair follicles extend into what layer(s)?

• Reticular layer of the dermis

• Sometimes the hypodermis

Root hair plexus

• Nerve endings connected to the root of a hair follicle

• Sense movement of har

Arrector pili muscle

What causes hair to stand up

Sebaceous gland

Produces sebum, oil, onto the surface of the skin

Merocrine sweat glands

• Do not extend very deep into dermis

• High concentration in palms and soles of feet

Apocrine sweat glands

• Extend deeper into the dermis than merocrine

• Coiled appearance

• In armpit and groin

Apocrine and merocrine sweat glands are all-or-none. What does this mean?

Once one gland is activated, they are all activated

What is the part of the nail you can see?

Nail body

Lunula

White area at the bottom of the nail body where blood vessels are obscured

What is the impact of fewer melanocytes with age?

• Pale skin

• Reduced tolerance for sun exposure

What is the impact of a thinner epidermis with age?

• Slow repairs

• Decreased vitamin D production

• Fragile skin that can bruise more easily

What is the impact of reduced sweat gland activity with age?

More likely to overheat