Group 7 - Integumentary System Flashcards
- Consists of the skin and accessory organs; hair, nails, and cutaneous glands
- Skin Covers 1.5 to 2.0 m2 ; composes 15% of body weight
- The skin is made up of two major tissue layers: the epidermis and the dermis
INTEGUMENTARY SYSTEM
covered by skin
1.5-2.0 m2
% body weight of skin
15%
two major tissue layers of skin
- epidermis
- dermis
integumentary system functions
- protection
- sensation
- vitamin D production
- temperature regulation
- excretion
- mechanical protection against abrasion and puncture
- effective barrier against bacteria
- moisture proofing against fluid loss or gain
- protect underlying cells against UV
- hair on the head act as heat insulator
- eyelashes protect the eyes from foreign objects; eyebrows keeps the sweart out of the eyes
- hair in the nose and ears
protection
- Integument has a variety of sensory receptors that can detect internal and external environmental change such as pain, touch, heat, pressure, etc.
- Sensory receptors in the skin detect stimuli like touch, pressure, temperature, and pain, sending signals to the brain for processing. Different receptors respond to specific stimuli, helping the body interact with its environment.
sensation
sensory receptors
- thermoreceptors
- nociceptors
- mechanoreceptors
how is vitamin D produced
- UV from sun converts cholesterol compound in our skin to vitamin D3
- vitamin D3 is transported to the liver and kidneys
- vitamin D3 is converted into its active form, 1,25- dihydroxyvitamin D
several mechanisms the skin regulates its temperature
- radiation
- convection
- conduction
- perspiration
integumentary system of invertebrates
- plasma membrane
- epidermis
secreted additional layer over the epidermis
cuticle
reflective cells
iridocytes
how are arthropod cuticles be hardened by
- calcification
- sclerotization
deposition of calcium carbonate in the outer layers of the procuticle, a process observed in crustaceans.
calcification
- protein molecules (sclerotin) bond together through stabilizing cross-linkages within and between adjacent lamellae of the procuticle
- process is observed in insects.
sclerotization
skin’s layers
- epidermis
- dermis
- hypodermis
- accesory organs
- made up of keratinized stratified squamous epithelium
- composed of distinct layers called strata
- prevents water loss & abrasion
- cells of the deepest strata perform mitosis
epidermis
- cells of the epidermis
- body’s most abundant epithelial cells
- contains large amounts of keratin
- gives the stratum corneum structural strength
keratinocytes
- deepest cell layer of the epidermis
- consist of cuboidal or columnar cells
- undergo mitotic division about every 19 days
stratum basale
- found right above stratum basale
- 8-10 cell layer thick
- Cells from the stratum basale migrate to stratum spinosum to undergo important changes as they continue to go upward.
startum spinosum
changes in the cells in stratum spinosum
- conversion of cuboidal cells into keratinocytes
- presence of desmosomes that adjoin adjacent cells
- found right above stratum spinosum
- 3-5 cell layer thick
- thin layer of cells in the epidermis
- cells in this layer assume the flattened appearance
- cells start to produce keratin and keratohyalin
- cells in this layer start to die
stratum granulosum
- thin, clear layer of dead cells
- found in areas of the body that are exposed to pressure, such as the palm, soles, and digits
- cells in this layer are dead & flattened
- rich in eleidin, a protein derived from keratohyalin
stratum lucidum
- The most superficial stratum of the epidermis
- thick layer with around 15-30 cell layers
- consists of 25 or more layers of dead squamous cells filled with keratin
- coated and surrounded by lipids
stratum corneum
- made up of dense collagenous connective tissue layer
- contains blood vessels, collagenous fibers, nerves, pigment cells, fat cells, and fibroblasts
- provides support, cushion, and nourishment of the epidermis
dermis
two regions of the dermis
- papillary layer
- reticular layer
- upper dermal region
- uneven and has fingerlike projections
- contains capillary loops
- furnish nutrients to the dermis
- has receptors (nociceptors & touch receptors)
papillary layer
how are dermal papillae in the palms of the hands, soles of the feet, and tips of the digits are arranged
parallel, curving ridges
- deepest skin layer
- contain blood vessels, sweat and oil glands, and deep pressure receptors
- contains immune cells like phagocytes
- made up of dense connective tissue
- main components : collagen and elastic fibers
reticular layer
components of the reticular layer
- collagen
- elastic fibers
- also called subcutaneous tissue
- made up of loose connective tissues, including adipose tissues
- contains about half of the body’s stored lipids
- for padding and insulation
hypodermis
- connects the skin to the underlying muscles & bones
- contains nerves and blood vessels
hypodermis
accessory organs of the skin
- hairs
- glands
- nails
- skin coloration (pigments)
- found everywhere on the skin except on palms, soles, parts of the genitalia, and distal segment of the fingers and toes
- epidermal outgrowths that function for protection
hair
parts of the hair
- medulla
- cortex
- cuticle
innermost layer of the hair shaft
medulla
surrounds the medulla
cortex
outermost part of the hair that covers the cortex
cuticle
- hair that is visible
- made of dead cells, keratin, and binding material
hair shaft
- forms the hair follicle that rests on the hair papilla
- region of the follicle that actively produces hair
hair bulb
- mass of connective tissue, nerve endings, and blood capillaries at the base of the hair follicle
- supplies the dividing hair cells in the hair matrix which enables hair growth
hair papilla
- Smooth muscle cells
- Contraction causes a raised area of the skin
arrector pili
three types of hair
- lanugo
- vellus hair
- terminal hair
fine hair that covers nearly the entire body of embryos
Lanugo
short, fine, “peach fuzz” body hair that grows in most places on the human body in both sexes
Vellus hair
fully developed hair
terminal hair
secrete various products
glands
- usually connected to hair follicles
- secrete sebum
- found all over the body except for the palms and soles of the feet
- sebum protects the skin from drying out, friction, and oxidative damage
sebaceous glands
- also known as sudoriferous glands
- simple, coiled, tubular glands that secret watery fluid called as sweat
- activated by nerves that respond to stimuli
sweat glands
two types of sweat glands
- eccrine
- apocrine
- release sweat by merocrine secretion
- produce diluted sweat
- found in almost all areas of the skin
- for thermoregulation
- play a role in the epithelialization ofhuman wounds
eccrine sweat glands
- cells in this gland release their secretory products by budding off the apical layer ofthe cell
- found in arm pits and near the genitals
- secretion is rich in organic matter
apocrine sweat glands
- found in the outer ear
- secrete cerumen or earwax
- seep out wax to keep the tympanic membrane (eardrum) soft, pliable, and water proof
- protection of the ear canal against physical damage and microbial invasion
ceruminous glands
- found only in mammals
- functional only in females
- produce mixture milk, of a watery fats, carbohydrates, and proteins via apocrine secretion
mammary glands
can differentiate into mammary glands
milk lines
- found mostly in amphibians
- water and temperature regulation
- reproduction
- produce a slimy, protective layer of mucus
mucous glands
- known as preen glands
- only found in birds and are located at the base of the tail behind the pygostyle
- secrete fluids rich in lipid and protein
uropygial glands
- scale-like modification of the epidermis
- made of keratin, a hard, tranluscent material
nails
visible part of the nail, and ismade up of compact onychocytes
nail plate
specialized part of the epidermis where the nail grows and contains blood vessels, nerves, and melanocytes
nail bed
active tissue that produces the cells that become the nail plate
nail matrix
produced by the physical structure of the surface tissue
skin coloration
factors that determine skin color
- pigments in the skin
- blood circulating through the skin
- thickness of the stratum corneum
two primary pigments
- melanin
- carotene
diseases of the integumentary system
- burns
- skin cancer
- bacterial infections
- viral infections
- fungal infections
- allergic reactions
- eczema
