Integumentary 2 Flashcards
What are the functions of the dermis?
- Gives the strength and elasticity to skin
- Contains many of the epidermal appendages, nerve corpuscles, and glands
- Contains the smooth muscle cells that move the hairs
- Around areole, penis, scrotum and perineum,, smooth muscle cells form a loose plexus in the reticular layer
- This accounts for the puckering of the skin at these sites, particularly in erectile organs
What is the papillary layer of the dermis?
- superficial layer
- loose connective tissue(more cells)
- contains blood vessels
- predominantly type 1 and 3 collagen fibers
- the elastic fibers are threadlike & form an irregular network
- Relatively thin and includes the substance of the dermal papillae and dermal ridges
Contains Meissner’s corpuscles
Describe the reticular layer of the dermis
- considerably thicker than and deep to papillary layer
- dense irregular connective tissue (less cells )
- Characterized by thick irregular bundles of mostly type 1 collagen and courser elastic fubers
What is the physiological basis for fingerprinting?
Areas of increased mechanical stress has deeper epidermal ridges and longer, more closely spaced dermal papillae
Responsible for fingerprinting
What are the associated appendages of the dermis?
- hair follicles and hair
- sweat glands
- sebaceous glands
- nails
- mammary glands
What are epithelial appendages?
All are down growths of the epidermis inti the dermis during embryological development
Modified to perform specific duties
Epithelial appendages include…
Hair follicles and hair
-nails
- glands
- eccrine
- sebaceous
- apocrine
Describe nails as epithelial appendages
Hard plates of epidermal keratinized cells
Present on the dorsal surface on the distal phalanx of the fingers and toes
What are the functions of the nail?
Help with grip
Gives protection
What are the parts of the nail?
Nail plate:
- The visible part of the nail
- rests on the nail bed (epidermis of the skin-hyponychium) and nail matrix
Nail root
- Found proximal to the nail nail plate
- covered with a fold of skin (eponychium)
What is the nail matrix?
Nail matrix- lies deep to (beneath) the nail root
Cells from here proliferate to form the nail itself
-Grows 1 min/week by deposition of hard keratin
What are hair follicles?
- Cylindrical shafts composed of keratin
- extends into the hypodermis
- produced in follicles
- associated with sebaceous gland
- hair follicle plus sebaceous gland and smooth muscle (arrector pili)= pilosebaceous organ/unit
Where is the fair follicle located?
In thin skin only
What does the hair follicle consist of?
- Infundibulum
- Isthmus
- Inferior segment
What does the bulb of the hair follicle consist of?
Bulb contains the matrix cells for hair formation
-melanocytes stem cells are found in the bulb