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