Integument System Flashcards
T/F the integument system is the largest organ
true
what is the function of the integument system?
- protection
- prevents desiccation
- temperature regulation
- excretion
- vitamin D synthesis
- sensory reception
how does your body temperature regulate?
sweating, vasodilation, hair follicles, erector pilli (goosebumps)
what is the layer of the skin in order?
epidermis, dermis, hypodermis, deep fascia muscle
epidermis
superficial, composed of epithelial tissue, upper layer actively shed
what type of tissue is the epidermis consisted of?
keritanized stratified squamous epithelium
dermis
deeper , composed of fibrous connectiove tissue
what type of tissue is the dermis consisted of?
areolar and dense connective tissue
hypodermis
deepest, subcutaneous layer, often not considered part of the integument system
what kind of tissue os the hypodermis consisted of?
adipose tissue
what cells are found in the epidermis?
keratinocytes, melanocytes, dendritic cells
keratinocytes
arise from the basal layer via mitosis, differentiate as they move towards the surface, become filled with keratin and secrete glycolipids which provides physical and antimicrobial shield and waterproofing
melanocytes
produce melanin pigment from melanosomes for uv radiation protection, passed to keratinocytes
dendritic cells
antigen-presenting immune cells
what are the 5 distinct regions of the epidermis?
- stratum basale
- stratum spinosum
- stratum granulosum
- stratum lucidum
- stratum corneum
stratum basale
basal-most layer, separated from the dermis by thin basement membrane; single row of columnar keratinocytes with rapid mitotic division (also contains tactile epithelial cells and melanocytes)
stratum spinosum
many layers, keratinocytes produce keratin intermediate filaments, cells begin to shrink and become spiny
stratum granulosum
3-5 layers of flattened cells; cells contain lamellar granules and keratohyalin granules
lamellar granules
release glycolipids
keratohyalin granules
crosslinks keratin intermediate filaments together
stratum lucidum
clear layer, few rows of flattened dead keratinocytes (only in thick palm and sole)
stratum corneum
very thick with shingle like dead cells filled with keratin (20-30 layer of dead cells)
what type of tissue is the dermis made of?
superficial areolar and deep irregular dense connective tissue
what cells are found in the dermis?
fibroblasts, dermal dendritic cells, macrophages, mast cells
fibroblasts
produce ground substance and collage for structural support and elastin for flexibility
mast cells
immune and inflammatory responses, release histamine, prostaglandins, leukotrienes, cytokines, and cheekiness
what are the 2 distinct regions of the dermis?
papillary dermis and reticular dermis
papillary dermis
(20%); areolar connective tissue, dermal papillae extend into epidermis for strength and increased surface area; mainly for nutrient and gas exchange between layers
reticular dermis
(80%); dense irregular connective tissue, contains nerves and vasculature
what is the dermal papillae responsible for?
- elevates overlying epidermis forming fingerprints, toe prints etc.
- Aids in gripping surfaces
cleavage lines
- represents separations between large parallel bundles of collagen fibers in the reticular dermis.
- Aligned to resist tensile force.
flexure lines
- Dermal folds positioned near or at joints, reult from dermis being tightly attached to underlying fascia.
- Secure skin during joint movement
striae
stretch marks; result from dermal tearing
what is the hypodermis and what does it do?
consists of areolar and adipose connective tissue, anchors overlying skin with underlying muscle, insulator and fat storage
cutaneous nerves
indicate touch, pain, itch and temerature
touch
taction
pain
nociception
itch
pruritoception
temerature
thermoreception
cutaneous nerves can be mapped onto the body surface as a series of discrete bands called?
dermatomes
what is a nail and what is its function?
- scale like modification of the epidermis consisting of hard keratin
- protects the distal phalanx and enhances delicate movement/ precision in grip
nail plate
- possesses a nail edge and root
- lines in nail bed are the deep layers of epidermis
nail matrix
the region of the bed that produces the nail (thick exposed opaque region forms lunule)
Is the nail a visual indication of a persons health?
yes
what is the function of hair?
sensory (light touch), protection, heat regulation
what 3 layers is the hair shaft composed of?
medulla, cortex, cuticular scales
where does the hair develop?
- developed in the follicles (stratum basale but rooted in the dermis)
- hair matrix is responsible for producing hair shaft (provides nutrients)
why do seniors go grey?
melanocytes stop producing
what does the hair follicle wall consist of?
peripheral connective tissue sheath, glassy membrane, epithelial root sheath
what kind of muscle does the erector pilli use?
smooth muscle; part of the autonomic nervous system
anagen phase
- active growth phase (18 months to 7 years)
- matrix cells rapidly divide producing hair (0.3 mm per day)
catagen phase
- breif regression phase (3 weeks)
- cell division ceases, follicle undergoes involution and shrinks towards the scalp surface
- lower half of the follicle becomes attached to hair shaft forming a club hair
telogen phase
- resting phase (3 months)
- hair is shed after 3 months matrix cells are stimulated to start regrowing and follicle re enters anagen phase
cutaneous glands
- exocrine glands that secrete their products through a duct on the surface of the body
- includes sebaceous glands and sweat glands
sebaceous glands
- simple branched alveolar gland
- throughout the entire body except palms and soles
- sebocytes produce oily sebum via holocrine secretion
- lubricates the skin to protect against friction and pathogens and makes it more impervious to moisture
holocrine secretion
- product is released into the duct by the rupture of the plasma membrane which destroys the cell
- contraction of surrounding myoepithelial cels expels sebum into hair follicle and coats the hair
sweat glands (sudoriferous)
- appendages of the integument
- entire body, produce up to 500 ml sweat per day
what types of sweat glands are there?
eccrine, apocrine and apoeccrine sweat glands
eccrine sweat gland
- simple tubular
- highly concentrated on palms, soles, forehead
- coiled base is deep in the dermis
- duct superficially opens to a pore
- eccrine sweat is primarily a filtrate of blood and resists bacterial growth and aid in thermoregulation
merocrine secretion
product excreted via exocytosis from secretory cells into an epithelial walled duct and onto skin surface
eccrine sweat is produced in?
The glands coil where it is isotonic with the blood plasma
at low sweat rates in eccrine sweat glands salt is _________ and actively ___________ by the glands duct.
conserved, reabsorbed
at high sweat rates leads to ______ salt reabsorption and allows more water to _______ on the skin to increase _________ _________.
less, evaporate, evaporative cooling
contraction of ________ _____ surrounding the gland expels eccrine sweat secretion onto the surface of the skin
myoepithelial cells
what are stimuli for sweating?
thermal, emotional, gustatory
apocrine sweat gland
- simple tubular, associated with hair
- mostly limited to the axilla (armpits) and pelvic areas
- functional at puberty
- produces a thick substance containing lipids and proteins along with true sweat that produces pheromones
what are examples of modified apocrine glands?
- ciliary glands (eyelid secretions)
- ceruminous glads (earwax)
- mammary glands (milk)
what is the process of apocrine secretion?
when a portion of the apocrine sweat gland containing apocrine sweat pinches off and enters the duct. then the contraction of myoepithelial cells surrounding glands expels apocrine sweat secretion into hair follicle onto skin surface
