BIOS251 Weeks 5-7 Edapt Outline
Week 5 Concepts– Integumentary System
General composition and function of Integumentary System
Structure of Skin
o Epidermis – Keratinized stratified epithelium
o Dermis
o Subcutaneous layer (hypodermis)
Accessory Structures
o Sweat glands
o Oil (sebaceous) glands
o Hair
o Nails
Functions of Skin
1. Protection- against dehydration and infection (includes acid mantle, keratin,
antimicrobial peptides)
2. Synthesis of Vitamin D- contributes to bones
3. Sensation – skin is largest sense organ: tactile, thermal, pain
4. Thermoregulation -regulating body temp in cold and hot environment, sweat
and evaporation
5. Nonverbal communication- expressive faces, general appearance of skin/hair
Gross and microscopic anatomy of integumentary system
, Epidermis- comprised of 5 cell types: Come Let’s Get Sun Burned
1. Keratinized stratified squamous epithelium
2. Keratinocytes – Keratin
3. Melanocytes – Produce melanin
4. Langerhans cells - Immune
5. Merkel cells - Tactile
o Thick Skin – found on the palms of the hands and soles of the feet. Contains
the stratum lucidium. AKA: Hairless skin
o Thin skin – found everywhere else on the body. Does not contain a stratum
lucidium. AKA: Hairy skin
Dermis
, o Cutaneous Membrane – dermis + epidermis
o Composed of collagen, elastic, and reticular fibers
o Blood vessels and nerve endings, cutaneous glands, hair follicles, hair roots
o Dermal papilla - projections from dermis, grooves called epidermal ridges.
Forms fingerprints.
o Papillary Layer – most superficial layer of dermis
Made of areolar tissue
Rich in blood supply
o Reticular Layer – deeper, thicker layer of dermis
Dense irregular tissue, collagen & elastic fibers
Hair follicles, hair roots, nerve endings, cutaneous glands
Meissner corpuscles – respond to touch
Pacinian corpuscles – respond to deep pressure and vibration
Ruffini corpuscles – respond to light pressure
Produces stretch marks (striae) due to collagen fibers tearing
o Blisters – form as result of fluid seeping out of blood vessels, accumulating
between epidermis and dermis.
Subcutaneous Layer (Hypodermis)
o Consists of loose connective tissue (adipose, areolar)
o Well-vascularized
o Connects skin to fascia beneath it
o Provides insulation, stores fat
Roles of specific tissue, layers of skin and the subcutaneous tissue
Functions and cells of the Epidermis
o Keratinocytes
90% of epidermal cells
Produce keratin- toughens and protects skin
Produces granules for water- proofing, prevents entry of pathogens
o Melanocytes
Produce melanin pigment
Stratum basale
Long slender projections connect with keratinocytes, melanin
shuttled there
Form protective shield over nucleus to protect DNA from UV damage
once inside keratinocyte.
o Langerhans Cells
Week 5 Concepts– Integumentary System
General composition and function of Integumentary System
Structure of Skin
o Epidermis – Keratinized stratified epithelium
o Dermis
o Subcutaneous layer (hypodermis)
Accessory Structures
o Sweat glands
o Oil (sebaceous) glands
o Hair
o Nails
Functions of Skin
1. Protection- against dehydration and infection (includes acid mantle, keratin,
antimicrobial peptides)
2. Synthesis of Vitamin D- contributes to bones
3. Sensation – skin is largest sense organ: tactile, thermal, pain
4. Thermoregulation -regulating body temp in cold and hot environment, sweat
and evaporation
5. Nonverbal communication- expressive faces, general appearance of skin/hair
Gross and microscopic anatomy of integumentary system
, Epidermis- comprised of 5 cell types: Come Let’s Get Sun Burned
1. Keratinized stratified squamous epithelium
2. Keratinocytes – Keratin
3. Melanocytes – Produce melanin
4. Langerhans cells - Immune
5. Merkel cells - Tactile
o Thick Skin – found on the palms of the hands and soles of the feet. Contains
the stratum lucidium. AKA: Hairless skin
o Thin skin – found everywhere else on the body. Does not contain a stratum
lucidium. AKA: Hairy skin
Dermis
, o Cutaneous Membrane – dermis + epidermis
o Composed of collagen, elastic, and reticular fibers
o Blood vessels and nerve endings, cutaneous glands, hair follicles, hair roots
o Dermal papilla - projections from dermis, grooves called epidermal ridges.
Forms fingerprints.
o Papillary Layer – most superficial layer of dermis
Made of areolar tissue
Rich in blood supply
o Reticular Layer – deeper, thicker layer of dermis
Dense irregular tissue, collagen & elastic fibers
Hair follicles, hair roots, nerve endings, cutaneous glands
Meissner corpuscles – respond to touch
Pacinian corpuscles – respond to deep pressure and vibration
Ruffini corpuscles – respond to light pressure
Produces stretch marks (striae) due to collagen fibers tearing
o Blisters – form as result of fluid seeping out of blood vessels, accumulating
between epidermis and dermis.
Subcutaneous Layer (Hypodermis)
o Consists of loose connective tissue (adipose, areolar)
o Well-vascularized
o Connects skin to fascia beneath it
o Provides insulation, stores fat
Roles of specific tissue, layers of skin and the subcutaneous tissue
Functions and cells of the Epidermis
o Keratinocytes
90% of epidermal cells
Produce keratin- toughens and protects skin
Produces granules for water- proofing, prevents entry of pathogens
o Melanocytes
Produce melanin pigment
Stratum basale
Long slender projections connect with keratinocytes, melanin
shuttled there
Form protective shield over nucleus to protect DNA from UV damage
once inside keratinocyte.
o Langerhans Cells
