- Integument (skin)
- Sweat and oil glands
The Integument (Skin)
Epithelium -Stratified squamous covering tissue on top
Connective tissue- Dense irregular
Connective Tissue- Adipose
Combining Tissue/Structures to Form an Organ and System
Epidermis and Dermis create Cutis. Cutis and Tela Subcutanea or Hypodermis (the layer beneath the cutis) create Integument
Functions of the Integument system
- #1 Protection against infection: barrier resisting microbial invasion.
- #2 Prevention of H2O loss: protective barrier that resists mechanical, chemical, osmotic, thermal and photic damage.
- #3 Temperature regulation: regulates body temperature via control of local blood capillaries and through evaporative cooling from sweating.
- #4 Synthesis of Vitamin D: serves many biochemical functions such as the formation of vitamin D and various growth factors.
- Stratified Squamous epithelium
- Any damage to epidermis will not draw blood
- Has 5 layers (stratum = layer)
5 Layers (Stratum) of the Epidermis
- Stratum CORNEUM
- Stratum Lucidum
- Stratum Granulosum
- Stratum Spinosum
- Stratum BASALE
Stratum Basale (germinativum)
- Cell division takes place (happens)
- Making new skin cells all day
2 Basic Cell Types
Melanocytes and Keratinocytes
- Produces melanin which is a protective protein pigment.
- Melanin shields the cell nuclei from harmful UV rays.
- Most abundant cell in epidermis
- produce keratin which is a protein that TOUGHENS and WATERPROOFS the skin.
- Mitotically active (divide frequently)
- Protective layers of dead, flat keratynocytes
- Ranges from a few cells to over 50 cells in thickness.
- Dense irregular connective tissue (with a small amount of loose CT)
Dermis has 2 layers
- Stratum papillare
- Stratum reticulare
If you are cut and bleed, then the laceration is at least as deep as the dermis.
Dermal papilla:peg-like projection that houses small blood vessels and nerve endings.
Function of Papilla
- Anchor epidermis to dermis
- Improve sensation (nerve endings)
- Friction ridges
- Provides blood supply to epidermis
On thick palmer and plantar skin friction ridges formed are unique fingerprints.
- Dense irregular CT
- Deep 80% of dermis
- made of bundles of collagen fibers called reticular fibers
Stratum reticulare Function
These reticular fibers in the dermis form cleavage lines
- caused by separation or less dense regions between collagen
- Stretch marks "striae"
Subcutaneous Layer or Hypodermis
Tela subcutanea aka superficial fascia
Subcutaneous layer or hypodermis aka tela subcuntanea
Mainly adipose CT some loose CT
Subcutaneous Layer or Hypodermis aka Tela subcutanea has 2 layers
Fatty layer and fibrous layer
- energy storage
Attaches to the deep fascia
rapidly dividing cells push into the deeper layers of the skin
this process accounts for the development of hair follicles and glands of the skin
This is an invagination of the epidermis. The hair follicle is NOT in the dermis.
- long, bag-like structure that houses and produces the hair.
- Epidermal invagination.
- Made of stratified squamous epithelium
Follicle-Relation to Dermal papillae
- The capillaries of a dermal papilla bring nutrients to the base of the hair follicle.
- Hair (pilus) made of dead keratinized cells
- Pathology Hypertrichosis
Deep (muscular) Fascia
- Continuous sheet of fibrous tissue that envelopes the body
- Located between the skin and muscles
Arrector Pili Muscle
- Smooth Muscle
- Raise/Straighten the hair follicle "goose bumps"
- Triggers: Cold, fear, anger
- produces an OILY substance called sebum that lubricates, moisturizes and helps waterproof the skin.
- Has antimicrobial (disease killing) properties.
Eccrine sweat gland -sudoriferous
- produces a clear, ODORLESS, WATERY fluid that cools the body
- Most numerous sweat glands of the body
Apocrine Sweat Gland
- produces an initially odorless fluid that under bacterial action becomes thick, SMELLY SWEAT
- least numerous, but largest sweat glands
- Found in armpits and groin and anal regions, nipples