HSCI 101_Chapter 6_Fall 2023

Integumentary
CHAPTER 6 System
INTEGUMENTARY SYSTEM
Skin
Hair
Nails
Sweat glands
Sebaceous (oil) glands

FUNCTIONS OF
INTEGUMENTARY SYSTEM
1. Protection
2. Immunity
3. Sensation
4. Thermoregulation
5. Waterproofing Maintain
homeostasis
6. Secretion and Absorption
7. Vitamin D synthesis
8. Communication
SKIN
STRUCTURE OF THE SKIN
Epidermis Hypodermis
Superficial region Subcutaneous layer
Epithelial tissue What type of CT?
What type of ET?
Avascular
Dermis
Underlies epidermis
Papillary layer
What type of CT??
Reticular layer
What type of CT??
CELLS OF THE EPIDERMIS
Keratinocytes Melanocytes
Major cell of epidermis Produce melanin
Produce keratin Located in stratum
basale and stratum
spinosum
Tactile (Merkel)
Dendritic Cells
(Langerhans) Cells Located in stratum
Patrol the stratum basale epidermis
spinosum Sensory receptors
Activate immune Touch
system
LAYERS OF THE EPIDERMIS
Thin Skin
Thick Skin
superfic
1. Stratum Corneum ial 1. Stratum
2. Stratum Lucidum
Corneum
2. Stratum
3. Stratum Granulosum
Granulosum
4. Stratum Spinosum
3. Stratum
5. Stratum Basale Spinosum

Hands and Feet dee 4. Stratum Basale
p Almost all of your

body
Come, Lets Get
STRATUM BASALE
Deepest epidermal layer
Attached to the dermis
Consists of:
Keratinocyte stem cells
Melanocytes
Tactile (Merkel) cells
STRATUM SPINOSUM
Daughter cells from stratum basale
Consists of:
Spikey-looking keratinocytes
Melanocytes
Dendritic cells
STRATUM GRANULOSUM
Layers of thin keratinocytes
Keratinization begins
Keratinocytes fill with keratin precursors
Nucleus and organelles disintegrate
STRATUM LUCIDUM
Only in thick skin
Thin, translucent band of keratinocytes
Two-three rows
Flat
Dead
Filled with protein, eleidin
STRATUM CORNEUM
Most superficial layer
20-30 rows of keratinized cells
Anucleated
Dead
Sloughed off
Calluses
Provide majority of skin functions
DERMIS
Deep to epidermis Contents
Cells
Two layers Fibroblasts
Papillary WBCs
Reticular Macrophages
Mast cells
Nerves
Blood vessels
Hair follicles
Sebaceous glands
Sweat glands
DERMIS: PAPILLARY LAYER
Superficial layer
Areolar connective tissue
Fingerlike projections into epidermis
Dermal papillae
Friction ridges
Only in thick skin
Dermal and epidermal folds and valleys
Contain sweat pores
Fingerprint
DERMIS: RETICULAR LAYER
Composes ~80% of dermis
Dense irregular connective tissue
Irregularly arranged collagen bundles
Few elastic fibers
TENSION/CLEAVAGE LINES
AND STRIAE
Gaps between
collagen
Striae = stretch
marks
Affect healing
rates and Tearing of
formation of collagen fibers
scars
HYPODERMIS
“Subcutaneous” layer
NOT part of skin
Anchors skin to deeper structures
Composed of:
Areolar CT
Adipose tissue
Abundant blood supply

SKIN PIGMENTATION
Melanin Carotene
Mostly determines skin Yellow-orange
color
Protects keratinocyte DNA
Hemoglobin
Pinkish-red
UV exposure
Variations of
pigmentation
Freckle
Mole/nevus
Albinism
ACCESSORY STRUCTURES OF THE
INTEGUMENT: HAIR, NAILS, AND GLANDS
CUTANEOUS GLANDS
Review Chapter 5!
(Merocrin
e)
MEROCRINE (ECCRINE)
SWEAT GLANDS
Most prevalent type Function
Thermoregulation
Sweat composition
Water Location
Waste products Palms
Electrolytes Soles
Forehead
Release mechanism
Exocytosis
Via sweat pores onto
epidermal surface
APOCRINE SWEAT GLANDS
Sweat composition Function
Viscous milky substance Unknown
Fatty substances
Proteins Regions
Bacteria Axilla
Pubic
Release mechanism Anal
Exocytosis NOT apocrine
secretion
Ducts empty into hair
follicle
Active after puberty
SEBACEOUS GLANDS
Composition Function
Sebum Waterproofing
Waxy Immune
Oily
Cell fragments and debris Location
Bactericidal Everywhere
Release mechanism except palms
Holocrine and soles
Released into hair follicle
Increases after puberty
Influenced by hormones
HAIR
Dead, keratinized cells Functions
Protection
Located everywhere on
Facial expression
the body except:
Heat retention
Palms
Sensory reception
Soles thick
skin Visual identification
Lips
External genitalia
HAIR STRUCTURE
Regions
Shaft
Extends from the scalp
Keratinization is complete
Root
From bulb to surface
Keratinization is complete
Bulb
Swelling at base
Deep in dermis
Keratinization is occurring
S
GOOSEBUMPS
INTERNAL HAIR STRUCTURE
Cuticle
Single layer of keratinocytes
Contains hard keratin
Cortex
Multiple layers of keratinocytes
Contains hard keratin
Medulla
Only found in thick hair
Central core of keratinocytes
Contains soft keratin
HAIR GROWTH Hair Matrix
Actively dividing area
Hair Papilla
Dermal tissue
Contain capillaries
Sensory receptors
HAIR GROWTH AND LOSS
1 – 1.5 cm / month Hirsutism
↑ Hairiness
Begins in hair matrix
Alopecia
Stages Thinning of hair
Growth
Cells divide and push cell
Diffuse hair loss
further from blood supply Hair shed from all parts of scalp
Duration varies Male pattern baldness
Resting Loss of hair first from only crown
Mitosis in matrix ends region of scalp
Hair is pushed out or falls out
HAIR COLOR AND TEXTURE
Texture
Color
Melanin Lanugo
Increase or decreased Thin, nonpigmented hair
production 3rd trimester
Different types
Gray/white  ↓ melanin Vellus
Pale, fine hair
Primarily upper and lower limbs
Terminal
Coarse, thick, pigmented hair
Found on
Scalp, eyebrows, axillary and pubic
regions
NAILS
Composed of stratified
squamous epithelium
Filled with hard keratin
Functions
Protective cover
Tool
NAIL STRUCTURE
Nail plate Lunula
Nail body Nail folds
Nail root Eponychium (cuticle)
Free edge Hyponychium
Nail bed
Nail matrix

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Integumentary

Sebaceous (oil) glands

5. Stratum Basale Spinosum

p Almost all of your

Abundant blood supply

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