integumentary system - quiz #3 Flashcards
2 major layers of skin
EPIDERMIS: superficial thinner layer made of epithelial tissue
DERMIS: deeper layer made of thicker CT
(also hypodermis)
HYPODERMIS (subcutaneous layer)
-deep to dermis
-not part of skin
-made of areolar & adipose tissue
-attaches skin to underlying tissues & organs, stores fat as adipose tissue & insulates body
-contains pacinian corpuscles: pressure sensors
EPIDERMIS - function
resists damage & provides protection to underlying tissue
DERMIS - function
provides temperature stability & prevents dehydration
what is the epidermis composed of & 4 distinct cells
composed of keratinized stratified squamous epithelium & 4 distinct cells:
keratinocytes
melanocytes
macrophages
tactile epithelial cells
epidermis - layers
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
keratinization
-new cells from stratum basal slowly pushed to surface of epidermis
-as cells move superficially, they mature & accumulate more keratin
-undergo apoptosis & die
-dead cells continue to move superficially until they reach surface & slough off-
-excessive amount of sloughing off dead keratinocytes from skin / scalp = DANDRUFF
DERMIS
-deeper layer, below epidermis
-dense irregular CT, contains collagen & elastic fibers
-fibers create woven network with tensile strength, can also stretch & recoil
-blood vessels, nerves, glands & hair follicles
-thicker than epidermis – thickness varies (thicker on palm & soles of feet)
-leather = dried & treated dermis of animals
-few cells: fibroblasts, macrophages, adipocytes
fibroblasts (dermis)
makes extracellular matrix & collagen, critical role in wound healing
macrophages (dermis)
phagocytes, clean up crew
adipocytes (dermis)
stores fat
2 layers of dermis
papillary region
reticular region
HAIR ANATOMY
Hair shaft
Hair root
Hair follicle
Epithelial root sheath
Hair bulb
Papilla of hair
Hair matrix
Arrector pili
Hair root complex
skin glands
GLANDS: cluster of epithelial cells that secrete substance
2 main types: EXOCRINE & ENDOCRINE glands
*skin ONLY contains EXOCRINE glands
exocrine glands (skin)
-sebaceous (oil) glands
-sudoriferous (sweat) glands
2 types: eccrine & apocrine
-mammary glands specialized sudoriferous glands that secrete milk
-ceruminous (wax) glands
NAILS
Nail body/ plate
Nail bed
Free edge
Nail root
Nail matrix
Eponychium/ cuticle
Lunula
nail body/ plate
visible portion of nail
nail bed
skin below nail body
free edge
edge that extends out
nail root
portion buried in fold of skin
nail matrix
cells divide mitotically to produce new nail cells & nail growth of approx. 1mm per week
eponychium/ cuticle
secures nail to finger
lunula
white, crescent shaped part at proximal end of nail bed
PAPULE (terminology)
-solid elevation of skin with no visible fluid
-1-10 mm in size, may be brown, purple, pink, red
-may cluster causing papular rash
PUSTULE (terminology)
-small bumps/ blisters on skin that fill with fluid/ pus
-usually appear as white bumps surrounded by red skin
-look like pimples but larger
NODULE (terminology)
-growth of abnormal tissue
-similar to papule, but greater than 5-10 mm in width & depth
-most frequently found in dermis, deeper tissues & internal organs
CYST (terminology)
-enclosed sac like pocket of membranous tissue
-contains fluid, air/ other substances
-can occur anywhere in body & are mostly benign, vary in size
-if filled with pus = sign of infection & may turn into abscess
BULLAE (terminology)
-fluid filled sac/ lesion
-type of blister
-fluid trapped between layers of skin
-larger than 10mm
-seen in bullous impetigo
ABSCESS (boil/ furuncle) - (terminology)
-collection of pus causing redness, pain, warmth & swelling
-mostly caused by infection around hair follicle entering through skin barrier
-most common sites are skin of armpits, base of spine & groin
