|Functions of the Integumentary System? ||- external body covering.
- keeps water and other molecules in the body.
- insulates and cushions the deeper body organs.
- protects from bumps and cuts, chemical damage, ultraviolet radiation and bacteria.|
|what is on the uppermost layer of the skin, which helps prevent water loss from the body surface? ||- Keratin (tough protein helps to provide a durable overcoat for the body, protects deeper cells from the hostile environment)|
|What plays an important role in regulating heat loss from the body surface? ||- the skin's capillary network and sweat glands (both controlled by the nervous system)|
|what alerts us to bumps and presence of tissue damaging factors as well as to the feel of wind in our hair and caress? ||- Cutaneous Sensory Receptors ( part of the nervous system))
- located in the skin.|
|Epidermis? ||- consists of " keratanized", stratified squamous epithelial cells.
- composed of 5 layers of bed sheets. (stratum basale,spinosum,granulosum,lucidum and corneum)
- Avascular (no blood supply)|
|What type of cells are in the Epidermis? ||- Keratinocytes ( keratin cells) are cells that produce keratin, fibrous protein that makes the epidermis a tough protective layer.|
|Stratum Basale (deepest layer of the Epidermis) ? ||- Stratum Basale, contains epidermal cells that receive nourishment through diffusion of nutrients from the dermis.
- constantly dividing by mitosis.
- contains live cells.
- alternate name " stratum germinativum" means germinating layer.|
|Stratum Spinosum (spiky) ? ||- biggest layer of cells.
- contain intermediate filaments, most cells are dead.
- become flat and keratanized until they die and become the stratum lucidum.|
|Stratum Granulosum? ||- dead cells packed with pigment cells (Melanin)|
|Stratum Lucidum? ||- dead cells
- found in hairless, thick skin (palms of hands and soles of feet)
|Stratum Corneum? ||- top most layer (dead cells)
- 20-30 cell layers thick
- dead cell remnants cornified or corny cells (cornu= horn) are filled with Keratin.
|What is dandruff? What layer is responsible for dandruff? ||- the stratum corneum rubs and flakes slowly which is dandruff.
- average person sheds 40lb of flakes in a lifetime.
- new cells are replaced by the stratum basale in 25 to 45 days.|
|How is Melanin produced? ||- pigment that ranges in color.
- produced by cells called melanocytes, found in the stratum basale.|
|How does tanning occur? ||- when skin is exposed to sunlight this causes the melanocytes to produce melanin which gives the body a tan.|
|Dermis? ||- acts like a bandaid for the skin (protects organs)
- has loose connective tissue and fold dermal papilla act to increase surface area.
- has reticular areas, varies in thickness ( thick in the palms of hands and soles of feet but thin on the eyel|
|papillary layer in the dermis? ||- upper dermal region has projections called dermal papillae.
- contain capillary loops which furnish nutrients to the epidermis.
- house pain receptors ( free nerve endings) and touch receptors ( meissners corpuscles)|
|reticular layer in the dermis? ||- deepest skin layer (contains blood vessels, sweat and oil glands)
- contain deep pressure receptors ( Pacinian Corpuscles)
- Phagocytes are found here which help prevent bacteria from entering the body.
- collagen and elastic fibers are found h|
|What aids in maintaining body temperature in the dermis? ||- blood vessels|
|Hypodermis? ||- mostly fat cells.
- nucleus is pushed to the side.|
|Hair Root Plexus? ||- network of neurons in the hair.|
|Sebaceous Gland (exocrine glands) ? ||- secretes oily substances, contain sebum=grease
- reside in the dermis.
- found all over the skin, except on the palms of the hands and soles of the feet.
- ducts empty into hair follicles.|
|Sebum (substance made by the Sebaceous gland) ? ||- sebum keeps the skin soft and lubricated.
- sebum is a mixture of oily substances and fragmented cells.
- sebum contains chemicals that kill bacteria.|
|Sweat glands? ||- 2 types of sweat glands (Eccrine and Apocrine)
- more than 2.5 million per person.|
|Eccrine glands? ||- sweat gland that releases to the skin through a duct/pore.
- found all over body
- produces sweat, a clear secretion containing (water, salts, vit c, traces of metabolic wastes, and lactic acid)
- sweat is acidic and inhibits growth of bacteria|
|Aprocrine glands? ||- sweat gland, found in the axillary and genital areas.
- larger than eccrine glands, ducts release into hair follicles.
- secretion contains fatty acids and proteins and all substances present in eccrine glands.|
|Arrector Pili Muscle? ||- gives us goosebumps, controlled by ANS.|
|Pacinian Corpuscle? ||- covered with connective tissue, deeper in the body.
- pressure receptor|
|Meissners Corpuscle? ||- superficial in the body
- touch receptor|
|Keratinocytes? ||- packed with protein|
|Langerhans Cells? ||- dendritic cells|
|Melanocytes? ||- cells that make melanin|
|Merkel? ||- sensory and neuron cells|