Anatomy of Integumentary System Flashcards
skin contains
- 3 layers
- skin cells that absorb ultraviolet radiation to produce Vitamin D
- sensory organs
- exocrine glands
3 layers of skin
- epidermis
- dermis
- hypodermis (aka subcutaneous)
sensory organs
- merkel’s cells
- meissners corpuscles
- nociceptors
- pacinian corpuscles
- thermoreceptors
merkel’s cells
- mechanoreceptors: detect light touch and vibration
- located in epidermis
meissner’s corpuscles
- mechanoreceptors: detect light touch and vibration
- located in dermis
nociceptors
- detect pain
pacinian corpuscles
- detect pressure applied to skin
- located in dermis
thermoreceptors
- detect hot and cold
exocrine glands
- contain secretions that they release via ducts into epithelial surface/lining
- most = multicellular
types of exocrine glands in skin (2)
- sebaceous glands
2. sweat glands
sebaceous glands
- oil glands
- produce sebum (inhibits growth of harmful organisms keeps hair/skin from drying out)
sweat glands
- sudiferous glands: produce sweat
- secretory portion is located deep in dermis, long duct carries sweat to surface of skin
- allow for thermoregulation of body via perspiration
epidermis - type of epithelium?
- outer layer of skin
- made of stratified squamous epithelium
- avascular, gets blood supply/nutrients from basement membrane (basal lamina)
- 4 distinct layers
stratified
layers
squamous
flat
basal lamina
basement membrane that epidermis is connected to, gives epidermis its blood supply
4 layers of epidermis
- stratum corneum (dead bc so far from blood supply)
- stratum granulosum
- stratum spinosum
- stratum basale (connected to basement membrane)
stratum basale (in depth)
- cells constantly dividing to rebuild skin
- those cells are pushed to the external surface until dead and slough off (via washing or friction)
- takes ~ 30 days for cell to go from stratum basale to external surface of stratum corneum
- then stays at stratum corneum for ~20 days before sloughs off
- forms epidermal ridges (fingerprints)
cells of epidermis (5)
- melanocytes
- langerhans cells
- merkel’s cells
- keratinocytes
- fibroblast cells
langerhans cells
- first line of defense for body
- part of immune system
- identify foreign microorganisms before enter bloodstream
keratinocytes
- produce keratin (protects exposed surfaces of skin)
fibroblasts
- produce collagen –> helps stick epidermis cells together, gives skin elasticity
dermis cells/contents
- sweat/oil glands
- meissner + pacinian corpuscles
- collagen and elastic fibers
dermis
- two regions: papillary (superficial) + reticular (deep)
- higher water content than epidermis
- skin’s main blood supply comes from reticular region of dermis (extensive network of blood vessels that branch off main arteries, supply nerves, hair follicles, and glands within skin)
contusion
- aka bruise
- damage to one of the blood vessels in reticular region of dermis
- color comes from blood leaking into dermis
hypodermis
- made up mostly of adipocytes (fat cells)
- 2 layers: subcutaneous fat + subcutaneous tissue
- helps anchor dermis to layer of fat cells
- thick –> protects deeper tissues and organs from injury
subcutaneous injection
- meds/vaccine given deep to the dermis but superficial to muscle
- absorbed more slowly than if given directly into vein
dermatome
- area of skin innervated by one sensory nerve
innervation of skin
- sensory signals go from skin –> spinal nerve –> spinal cord –> brain
- all skin innervated by a spinal nerve except face (which is innervated by trigeminal branch of CN V)
hair
- 2 parts: root and shaft
- made up of dead epidermal cells converted to keratin
- stronger texture than skin cells
- hair follicles each connected to smooth arrector pili muscle (contracts when body cold or emotional response)
- follicles found throughout surface of skin, sensitive to hormones
root of hair
- located in dermis layer
- begins at hair bulb (which provides blood + nerve supply)
- contains subaceous gland to hydrate hair w/oil
shaft of hair
extends through epidermis to external surface of skin
nails
- dead epidermal cells, converted to keratin at nail root
- then pushed towards external surface in direction of nail body
cuticle
- stratum corneum covering nail root
lunula
- visible portion of nail bed near root
