Anatomy Chapter 5 (integumentary system)

What is the integument/it’s functions?

skin, first line of defense versus invasion by foreign organisms, modulates water loss and body temp

What are the 3 main layers of skin?

epidermis, dermis, and hypodermis

What is the epidermis?

outermost layer of skin, consists of stratified squamous epithelium

What are the 4 cell types of the epidermis?

keratinocyte, melanocyte, and dendrocytes (granstein and langerhans)

What are keratinocytes?

cell of the epidermis, produces keratin protein

What are melanocytes?

cell of epidermis, produces melanin, gives skin color, blocks and absorbs UV

What are dendrocytes?

2 types: langerhans and granstein cells; mediate the immune response, sit above basal keratinocytes

What are langerhans cells?

UV sensitive cells that interact with helper T cells

What are granstein cells?

cells that are less sensitive than langerhans cells, interact with suppressor T cells

What are the 4/5 layers of the epidermis (order from superficial to deep)?

stratum corneum, stratum lucidum (only thick skin), stratum granulosum, stratum spinosum, stratum basale

What is the stratum basale?

deepest epidermis layer, contains stem cells and melanocytes, also contains meissner corpuscle nerves (soft touch nerves)

What is the stratum spinosum?

second deepest epidermal layer, tightly packed cells that contain melanin, 8-10 rows

What is the stratum granulosum?

3rd deepest epidermal layer, 3-5 rows flattened cells that contain keratohylain (cells bulking up on keratin). this is the first stage of keratinization of cells where the cells are in varying stages of degeneration

What is the stratum lucidum?

2nd most superficial layer of epidermis, only found in thick skin, 3-5 rows of flat, dead cells containing eleidin (almost keratin)

What is the stratum corneum?

topmost layer of epidermis, 25-30 rows of keratinized stratified squamous epithelium, continuously shed and replaced

What is the dermis?

2nd deepest skin layer, composed of connective tissue, collage, and elastic fibers; supports numerous blood vessels, nerves, hair follicles, and glands

What are the two regions of the dermis?

papillary and reticular

What is the papillary region?

superficial layer of dermis, projects into epidermis; contains capillaries, nerve endings, has ridges that extend bump-like upward

What is the reticular region?

deep layer of the dermis, thickly invested with connective fibers, provides skin with strength, extensibility, and elasticity; attached to underlying bone/muscle; pacinian corpuscle nerves found here (deep touch)

What are the functions of skin?

regulation of body temp, protection and immunity, reception of stimuli, exertion of small amounts of water, salts, and small organic molecules, UV dependent synthesis of vitamin D

What are the three epidermal derivatives?

hair, glands, and nails

What is hair?

consists of keratinized cells that form a shaft and bulb rooted in the dermis, surrounded by a hair follicle

What are arrector pili?

smooth muscle that is connected to hair follicle, movement of muscle causes goosebumps

What are sebaceous glands?

oil glands, open up into hair follicles to condition hair

What are the functions of hair?

mainly protection, some thought of there being an olfactory role or evolutionary remnant

What are sudoriferous glands?

sweat glands, produce watery secretion, regulate body temp

What are ceruminous glands?

glands that secrete cerumen into external auditory meatus

What are nails?

tightly packed and hardened keratinized cells

What is albinism?

lack of melanin pigment, genetic skin depigmentation

What is vitiligo?

skin depigmentation in which patches of skin lose pigment, uncertain cause but thought to be auto immune, common

What is another cause of skin depigmentation that isn’t genetic or auto-immune?

disease or parasite caused skin depigmentation

What is an eccrine sweat gland?

type of sweat gland that opens directly to the skin surface

What is an apocrine sweat gland?

type of sweat gland that opens to hair follicle