Integumentary System (Ch. 5) Flashcards
(46 cards)
function of integumentary system
→ acts as barrier & repels water
→ protects from abrasions, infections, dehydration
→ helps regulate body temp. (sweating, goosebumps)
→ acts as sensory organ
→synthesis of vitamin D
→ absorption/ excretion
thick vs. thin skin
thin skin thick skin
everywhere there palmar surface of hand
isn’t thick skin plantar surface of feet
→hair →NO hair
→oil glands → NO oil glands
→fewer sweat glands → MORE sweat glands
skin layers:
→ epidermis (superficial)
→dermis
→hypodermis
hypodermis
contains mostly adipose tissue with some areolar connective tissue
→anchors skin to underlying tissues, but still allows for some movement capability
NOT part of skin, but is part of integument
provides thermal insulation, storage site for triglycerides, shock absorption
dermis
deepest layer of skin
thick layer of connective tissue that consists mainly of collagen fibers, fibroblasts, and mast cells
→highly vascularized and innervated tissue
contains sensory corpuscles, glands (sebaceous, eccrine), lymphatic vessels
separated into 2 layers: papillary & reticular
papillary region of dermis
superficial-most layer of dermis
→made up of areolar connective tissue with many elastic fibers
→ contains Meissner’s (tactile) corpuscles
sensory receptors for light (sensitive) touch
located in DERMAL PAPILLAE
reticular region of dermis
deepest layer of dermis
→ made up of mostly dense, irregular connective tissue & small amount of areolar connective tissue
→allows for stretching of skin
tears in reticular later = stretch marks
→contains pacinian corpuscles
sensory receptors for deep touch
→contains 5 different types of glands, hair follicles, & associated smooth muscle structures
skin glands found in dermis layer
sweat glands (sudoriferous glands)
→apocrine glands
→eccrine (merocrine) glands
modified apocrine (sweat) glands
→ceruminous glands
→mammary glands
sebaceous glands
eccrine glands
most common type of sudoriferous (sweat) gland
found in large amounts in palms, soles of feet and forehead
secretes “true sweat”*
*mostly water, also salts, vitamin C, antibodies, anti-microbial protein & small traces of metabolic wastes
primary function: release/produce sweat to prevent overheating (thermoregulation)
apocrine glands
only found in axillary & anogenital regions
larger than eccrine glands, begin functioning @ puberty
secretes viscous, milky or yellowish sweat that contains fatty substances & proteins
→body odor is produced when these secretion components are broken down by bacteria on skin
exact function UNKNOWN
ceruminous glands
modified sudoriferous gland
found in external ear canal
secretes EARWAX (CERUMEN)
→deters insects, waterproofs ear canal, helps block entry of foreign material
mammary glands
modified sudoriferous gland
→milk-producing
→develop within a female breast’s during pregnancy & lactation
sebaceous glands
oil glands
found in all thin skin areas
larger on face, neck & upper chest, smaller in size on all other areas of thin skin
→secretes sebum (oil)
→prevents water loss
→softens & lubricates skin & hair
→inhibits bacterial growth
→secretes oil into hair follicle & arrector pili contraction forces it to surface
epidermis
keratinized, stratified squamous epithelium
5 important cells found in epidermal layer
- keratinocytes: synthesize keratin (waterproof & strengthens)
- basal cells: undifferentiated, immature skin stem cells
- dendritic (langerhans) cells: immunity cells
- melanocytes: synthesize melanin
- tactile (merkel) cells: touch receptors
layers of epidermis:
from deep to superficial:
→ stratum basale
→ stratum spinosum
→stratum granulosum
→stratum lucidum (FOUND ONLY IN THICK SKIN)
→ stratum corneum
beautiful skin gets lotion constantly
stratum basale
basal layer
deepest epidermal layer that’s attached to dermis
→ single layer of basal (stem) cells, the deepest layers of keratinocytes & some melanocytes
as cells go through mitosis, they’re pushed closer to surface
stratum spinosum
spiny layer
consists mostly of keratinocytes that are spikey-looking
stratum granulosum
grainy layer
4-6 layers of keratinocytes that are flattened
→ layer where keratinization begins
stratum lucidum
clear layer
thin layer that’s seen ONLY in thick skin
consists of 2-3 rows of dead keratinocytes
stratum corneum
cornified layer
consists of 30+ layers of dead, scaly keratinized cells
accounts for ¾ of epidermis thickness
dead but still helps to protect underlying layers
skin color
melanin produced by melanocytes determines color of skin, hair, & eyes
everyone has approx. same # of melanocytes but variations is due to amount of melanin pigment produced
exposure to sun causes melanocytes to make more melanin*
*blocks & absorbs excess UV LIGHT that cause cancer that may damage DNA of mother cells in basal layer
carotene
yellowish-orange pigment found in plant products
→ accumulates in stratum corneum & fat tissue of hypodermis
converted into vitamin A which is crucial for skin & eye health
erythema
red or pinkish hue under skin
→ caused by increased # of hemoglobin in capillaries of skin due to increased blood flow
can be caused by sunburns, inflammation, embarrassment, medications, allergies, fever, hypertension, etc.
