Download The Integumentary System

Chapter 6
The Integumentary System
Three Types of Epithelial
Membranes
• Serous Membranes
– Line cavities and cover organs
– Simple squamous epithelium over loose
connective tissue
– Parietal and visceral portions
– Secrete a serous (watery) fluid for
lubrication
Three Types of Epithelial
Membranes
• Mucous membranes
– Line cavities that open to the exterior
– Layer of epithelium over connective tissue;
epithelium varies with location
– Tight junctions and goblet cells
• Cutaneous membrane is the skin
– the major organ of the integumentary system
Integumentery System
A. Parts include • the skin and the organs derived from it
(hair, glands, nails, specialized
receptors)
• One of the largest organs
– 2 square meters; 10-11 lbs.
– Largest sense organ in the body
• The study of the skin is Dermatology.
Integumentary System
B. Considered an organ system
because . . .
• Organs are two or more tissues which
together perform a specialized function.
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
What are some functions
of the integumentary
system?
Brainstorming time!
Functions include:
1. Protection (immunity) - physical barrier to
environment
physical abrasion
dehydration
ultraviolet radiation
2. Sensation/sensory - responds to stimuli
touch
vibration
pain
temperature
Functions include:
3. Regulation of body temperature
– Cellular metabolism produces heat as a waste
product.
– High temperature
• Dilate surface blood vessels
• Sweating
– Low temperature
• Surface vessels constrict
• shivering
Functions include:
4. Excretion of wastes (perspiration)
5. Synthesis of vitamin D
stimulated by ultraviolet light
aids absorption of calcium
6. Prevent water loss - “impermeable”
barrier
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
Layers of the Skin
D. Layers of the Skin include Two main layers Epidermis*
Dermis
Subcutaneous layer or hypodermis
* Determines thickness of skin
Layers of the Skin
E. Epidermis
1. tissue type(s)
2. 4 types of cells
3. Thickness of the skin
4. Layers of the epidermis (bottom to top)
Layers of the Epidermis
• Stratum basale (stratum germinativum)
– Single layer of living cells
– Continuous cell division
– produce keratinocytes
– Melanocytes - # the same for all races
• Melanin produced in melanocytes
Layers of the Epidermis
• Stratum spinosum (spiny)
– 8-10 layers of living cells
– Function is support
– Keratinocytes take in melanin by cytocrine
secretion
Layers of the Epidermis
• Stratum granulosum
– 3-5 layers
– Keratinization begins here
– Cells beginning to die, nuclei still present
Layers of the Epidermis
• Stratum lucidum * (lucid = clear)
– More apparent in thick skin
– 3-5 layers of clear dead cells
– Eleidin
*Only found in palms & soles
Layers of the Epidermis
Stratum corneum (horny layer)
– Dead, flat cells full of keratin
– Keratin is waterproof
– Cells are shed continuously
• Basal cell to surface – about 2-4 weeks
Layers of the Epidermis
Mnemonic devices???
Canadian ladies give superb backrubs.
Can little girls speak German?
Can Lauren get some booty?
The Dermis
F. Dermis
1. Tissue types - Connective tissue with
collagen and elastic fibers,also has
nerves, blood vessels, muscle fibers, hair
follicles and glands
The Dermis
F. Dermis
2. Papillary layer
– Top 1/5 of dermis – loose connective
tissue
– Highly vascular
– Dermal papillae - fingerprint patterns
– Functions of papillae
The Dermis
F. Dermis
3. Dermatoglyphics
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
The Dermis
4. Reticular (net) layer (bottom 4/5)
– Dense irregular connective tissue
– Sebaceous (oil) glands
– Hair follicles
– Ducts of sudoriferous (sweat) glands
– Striae or stretch marks
– Functions
Subcutaneous Layer
(Hypodermis)
G. Subcutaneous layer
1. Tissue types
2. Types of fibers
3. Functions
4. Changes during lifetime
Skin color
• Genetic factors - most important
• Melanin, carotene, & blood vessels
– Everyone has the same number of
melanocytes
– Difference is how much melanin is made
• Environmental factors
– UV light or x-rays
Albinism - albinos
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Skin Color
• Melanin is made in melanocytes
• S. basale and s. spinosum
• Melanin absorbed via cytocrine
secretion/phagocytosis
• Carotene found in s. corneum and fatty
areas of dermis
• Caucasians have less melanin &
carotene in epidermis
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
Accessory Organs
• Hair (pili)
– Dead epidermal cells
– Function in protection
• Scalp hair - sun (UV radiation)
• Eyebrows & eyelashes
• Nose & ear
– Touch
The Strength of Hair
QuickTime™ and a
decompressor
are needed to see this picture.
The Strength of Hair
QuickTime™ and a
decompressor
are needed to see this picture.
Accessory Organs
Hair Structure
Shaft, root, and follicle
3 parts of shaft (outside to middle)
cuticle
cortex*
medulla*
Root has same 3 parts.
* = contains pigment
Accessory Organs
Hair
Hair follicle - tube-like depression at base of
hair
Surrounds root
Downgrowth of epidermis in third
month of fetal development, then hair
grows to surface- inside the follicle
Accessory Organs
Hair
Bulb - enlarged area at bottom of hair;
contains papilla
Papilla - contains capillaries that nourish hair
Accessory Organs
Hair
– Sebaceous glands keep hair from drying out
– Arrector pili muscle (goose bumps)
– Hair growth and replacement have a cyclical
pattern
– ‘male-pattern’ baldness (genetics/inherited)
– Hair color - genes control type and amount of
pigment deposited
Going Gray
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
Alopecia
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
Nails
• Plates of highly packed, keratinized
cells
• Functions - protection, gripping,
grasping & manipulation
• Formed by epidermal cells in nail bed
called the matrix
• 1 mm / week
Nail Growth going to extremes
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
World's Longest Fingernails
Lee Redmond, a 66-year-old great grandmother from Utah,
currently holds the Guinness World Record for longest
fingernails.
Nails
• Parts of a nail:
– Nail body - the nail itself
– Free edge - distal end, white due to no
tissue underneath
– Nail root - nail growth, under the skin
– Nail matrix - responsible for nail formation
– Nail bed - tissue under nail, light pink due
to tissue underneath
Nails
• Parts of a nail:
– Lunula - “half moon” at proximal end of
nail; area of most rapid growth
– Eponychium- thickened stratum corneum
at proximal end of nail; known as the
cuticle
– Hyponychium - thickened stratum corneum
underneath nail
End of Part 1 of the
Integumentary System