what is the integumentary system?
the skin and its derivatives (sweat and oil glands, hairs) make up a complex set of organs that serves several functions, mostly protective
which anatomical structures are important for preventing infection and why?
(four answers)
epidermis is protective due to the keratin, which is a thick/dense protein
sweat and secretion include DNAses, RNAses, and antimicrobials
sebum/oil provides a water barrier and allows bugs to wash off the oily skin
dendritic cells, part of the immune system, are APC that will help the adaptive immune system
how is classification of ulcers and burns based on the anatomy of skin? why would a fourth degree burn involve?
ulcers are skin areas that don’t heal well, such as pressure sores or leg ulcers that develop when they’re bed ridden or have diabetes
Burn degrees range from 1-4 and it depends on the deepness of the burn
1) superficial - epidermis
2) dermis (blister)
3) hypodermis
4) burn to muscle or bone
what is a blister and what is the anatomy of a blister?
Blisters develop when:
- papillary layer is rubbed
- damage to subpapillary plexus
- buildup of fluid between epidermis and dermis
- if you pop it- risk infection to dermis
adipose tissue
- makes up the hypodermis layer
- above the fascia
apocrine sweat gland
- confined to the axillary and anogenital areas
- they are merocrine glands, which release their product by exocytosis like the eccrine sweat glands
- these are larger than eccrine glands, apocrine sweat glands lie deeper in the dermis or even in hypodermis and their ducts empty into hair follicles
- these begin functioning at puberty uner influence of androgens
arrector pili muscle
- associated with each hair follicle is a bundle of smooth muscle cells called the arrector pili
- contraction pulls the hair follicle upright to make goose bumps IRT cold temperature
cutaneous plexus (deep plexus)
cutaneous plexus is the network of blood vessels that nourishes the reticular layer in the dermis layer. cutaneous plexus is between the reticular layer and the hypodermis
dermal papillae
- peglike projections from papillary layer
- overlaps with epidermis
- contain capillary loops
- house free nerve endings (pain receptors)
touch receptors (tactile or meissner’s corpuscles)
dermis
- bulk of the skin
- tough, leathery layer composed mostly of fibrous connective tissue
- vascularized
- cells = fibroblasts, macrophages and occasional mast cells and WBC
- two layers - papillary and reticular layers
eccrine (merocrine) sweat gland
- more numerous and are particularly abundant on the palms and soles of feet and forehead
- simple coiled, tubular gland
- secretory part lies coiled in the dermis
- sweat duct extends into a funnel shaped pore at the skin surface
epidermis
- composed of epithelial cells (mostly keratinocyte)
- outermost protective shield of the body
- nutrients reach the epidermis by diffusing through the tissue fluid from blood vessels in the dermis
- four/five layers
- four cell types - keratinocytes, melanocytes, dendritic cells and tactile cells
fascia (superficial and deep)
- layer below the hypodermis
- this layer covers muscles and bones
hair follicle
- folds from the epidermal surface into the dermis
- in scalp - extends hypodermis
hair papilla
- a nipple-like bit of dermal tissue, protrudes into the hair bulb
- contains a know of capillaries that supplies nutrients to the growing hair and signals it to grow
hair root
The root of the hair ends in an enlargement, the hair bulb,
hypodermis (subcutaneous layer of subcutis)
- the subcutaneous tissue just deep to the skin
- consists of mostly adipose tissue
- aka superficial fascia - superficial to the tough connective tissue wrapping (fascia) of skeletal muscles,
- anchors skin to the underlying structures (mostly muscles)
- shock absorber and an insulator (reduce heat lose)
nerve endings and receptors
- at dermal papillae, on dermis layer
- house free nerve endings (pain receptors)
touch receptors (tactile or meissner’s corpuscles)
papillary layer
- connective tissue
- interlacing collagen and elastic fibers form a loosely woven mat that is heavily invested with small blood vessels
- loose connective tissue - allow phagocytes and defensive cells to wader freel
reticular layer
- accounting for 80% of the dermis thickness
- dense fibrous connective tissue
- cutaneous plexus is the network of blood vessels that nourishes this layer. cutaneous plexus is between the reticular layer and the hypodermis
sebaceous gland
- oil glands
- branched alveolar glands that are found all over the body except thick skin
- secrete sebum
- most, but not all sebaceous glands develop as outgrowths of hair follicles and secrete sebum into a hair follicle or to a pore on the skin surface
subpapillary plexus
- network of blood vessels
- supplies blood and nutrients to the dermis layer
sweat duct
aka sweat glands
eccrine and apocrine sweat glands
sweat pore
- sweat duct is coiled in the dermis
- the duct extends to the open in a funnel shaped pore to the outside at the skin surface
