Integumentary System

baejuhyeoned's version from 2018-02-06 16:16

Section 1

Question Answer
Integumentary system organ system that protects the body from various kinds of damage, such as loss of water or abrasion from outside.
Integumentary systemcomprises the skin and its appendages (including hair, scales, feathers, hooves, and nails).
Skin is the largest organ of the human body
Skin is several layers deep of tissues and comprised of a number of different type of cells.
(1) epidermis, (2) dermis, and (3) hypodermisThree major layers of skin
Hypodermis is also known as the subcutaneous, or subcutis layer
Epidermis is the outermost layer of the skin
EpidermisIt contains stratified, squamous epithelial cells
Epidermis is avascular; meaning it does not have a blood supply of its own
EpidermisOxygen and nutrients diffuse up from the underlying dermi
EpidermisKeratinized stratified squamous epithelium
(1) Keratinocytes, (2) Melanocytes, (3) Merkel cells, (4) Langerhans cellsFour types of cells (EPIDERMIS(
Keratinocytesdeepest, produce keratin (tough fibrous protein)
Melanocytes make dark skin pigment melanin
Merkel cells associated with sensory nerve endings
Langerhans cellsmacrophage-like dendritic cells


Question Answer
Stratum basale or germinativum single row of cells attached to dermis; youngest cells
Stratum spinosum spinyness is artifactual; tonofilaments (bundles of protein) resist tension
Stratum granulosum layers of flattened keratinocytes producing keratin (hair and nails made of it also)
Stratum lucidum (only on palms and soles)
Stratum corneumhorny layer (cells dead, many layers thick)
Stratum corneumOutermost layer, about 15 to 30 cell layers thick
Stratum corneumNuclei no longer exist in these cells
Stratum corneumCompletely composed of dead cells – this is the furthest layer from the dermal blood supply
Stratum corneumVery flat, compacted cells – gives skin its protective property
Stratum corneumThese cells have been keratinized
Stratum corneumClosest to the surface, cells appear loosely dense, due to their constant shedding
Keratin is responsible for hardening and flattening the cells
Stratum lucidum2nd layer from the skin surface, composed of several layers of flattened, dead cells
Stratum lucidumNuclei are degenerated (broken down); only a few nuclei, if any, can be seen under the microscope
Stratum lucidumThin layer of the epidermis, Extremely difficult to identify in thin skin, almost appears translucent
Stratum lucidumA precursor to keratin can be found in these cells
Stratum granulosum3 rd layer from the skin surface
Stratum granulosumThin layer of the epidermis; A few layers deep in thick skin, one layer in thin skin
Stratum granulosumCells in this layer contain Lamellar granules
Stratum granulosumThese granules release lipids and proteins into the space above, causing the cells above to start losing their nuclei and organelles
Stratum granulosumThese granules also gives rise to a hydrophobic envelope that serves as the skins’ barrier
Stratum spinosum4 th layer from the skin surface
Stratum spinosumThickest layer of living keratinocyte cells
Stratum spinosum• Cells are irregular, polygons in shape
Stratum spinosumCells have tiny spine-like extensions protruding off the cell – giving this layer its name ‘spine’-osum
Stratum spinosumCells here are switching over from mitotic roles (dividing) into keratin production
Stratum spinosumThese are the cells that begin the formation of keratin precursors
Stratum basaleDeepest layer of the epidermis, found closest to the dermal blood supply
Stratum basaleContains a single, continuous layer of cuboidal keratinocyte cells that sit on top of the basement membrane
Stratum basaleServe as the stem cells of the epidermis
Stratum basaleStem cells- early cells that can become other types of cells (called differentiation)
Stratum basaleCells go through mitosis to continually replenish the layers of cells above
Stratum basaleThe further the cells get away from this layer, the sooner they die
(1) Melanocytes, (2) Merkel Cells, (3) Langerhans CellsStratum basale contains
Melanocytes These are cells that create melanin, the protein pigment that gives skin its color
Melanocytes These pigments also serve as protection for DNA from UV rays
Merkel CellsTouch receptors- nervous system
Langerhans CellsHelps against infection
Basement membraneThis is a thin, non-cellular region that separates the epidermis from the dermis
Basement membraneMostly composed of collagen fibers
Basement membraneAnchors the epidermis to the dermis

Section 2

Question Answer
(1) Epithelium, (2) Connective Tissue, (3) Muscle Tissue, (4) Nervous TissueFour basic types of tissue
DermisIs not composed of epithelial tissue, but connective tissue
(1) Dermal Papillary region, (2) Reticular Dermis Dermis is composed of two separate layers
Dermal Papillary regionContains terminal blood capillaries & • Meissener’s corpuscles – receptors of touch
Reticular Dermis Contains collagenous, elastic, and reticular protein fibers
Reticular Dermis • Gives skin its strength, extensibility, and elasticity
Reticular Dermis also contains hair roots, glands, blood vessels
HypodermisAlso known as the subcutaneous tissue
HypodermisDeepest, lowermost layer of the integumentary system
HypodermisAnchors the skin to the deep fascia below it
(1) Fibrous bands, (2) Adipose cells, (3) MacrophagesHypodermis is composed of
Fibrous bandsfor anchoring
Adipose cellsfor fat storing
Macrophagesfor protection
Melanin the most important skin pigment
Carotenefrom carrots and yellow vegies
Hemoglobinthe pink of light skin
Skin appendagesDerived from epidermis but extend into dermis
NailsPlates of stratified, squamous epithelial cells with hard keratin
NailsProtects the distal ends of phalanges- replaces the epidermis of the portion it covers
Lunula (the white crescent part of your nail, visible in the thumb)Nail growth occurs in the
Cuticleis a fold of stratum corneum on the proximal end of nail

Section 2.3

Question Answer
Hair and hair folliclesEverywhere but palms, soles, nipples, parts of genitalia
Hair and hair folliclesDerived from epidermis and dermis
ShaftThe hair that we see is actually the terminal endings of hair, called the
(1) Warmth, (2) Sense light touch of the skin, (3) Protection - scalpFunctions of hair
(1) Root embedded in skin, (2) Shaft projecting above skin surfaceParts of hair
Hard keratinMake up of hair
(1) Medulla (core), (2) Cortex (surrounds medulla), (3) Cuticle (single layers, overlapping)Three concentric layers (HAIR)
Root of the hairis anchored in a tubular invagination of the epidermis
Hair folliclesurrounds the root of the hair and extends down into the dermis, and sometimes the hypodermis
Hair follicleis the only living, growing part of the hair structure
Become keratinized and dieAs the cells divide and push the cells outward (hair growing out) the cells begin to __________
The arrector pili muscleis responsible for making your hair stand up on its end
Sweat glandsEntire skin surface except nipples and part of external genitalia
Sweat glandsPrevent overheating
Sweat glands500 cc to 12 l/day! (is mostly water)
(1) Apocrine, (2) EccrineThere are two different types of sweat glands
Apocrinefound mainly in the skin of the armpits, of the anogenital areas, and of the areola of the breasts. Their secretory portion is located in the dermis or hypodermis. Their ducts open into hair follicles. Their secretion is more viscous than that of the eccrine glands. They start secreting at puberty and may be analogous to the sexual scent glands of other animals (creating pheromones)
Eccrineare more common. Their secretory portion is located in the dermis or hypodermis. They produce sweat, a watery mixture of salts, antibodies and metabolic wastes. Sweat prevents overheating of the body and thus helps regulate body temperature.
Ceruminous glands (or ear wax glands) and mammary glandsare modified apocrine sweat glands.
Sebaceous glandssecrete the sebum (seb = oil) an oily product.
Sebumis usually secreted into a hair follicle.
Sebumhelps hair from becoming brittle
Sebumprevents excessive evaporation of water from the skin
SebumKeeps skin soft
Sebuminhibits the growth of certain bacteria.
Sebaceous glandsare scattered all over the surface of the skin except in the palms, soles and the side of the feet.

Section 2.3

Question Answer
(1) Eccrine or merocrine, (2) Apocrine, (3) Modified apocrine glands3 types of sweat glands
Eccrine or merocrineMost numerous
Eccrine or merocrineTrue sweat: 99% water, some salts, traces of waste
Eccrine or merocrineOpen through pores
ApocrineAxillary, anal and genital areas only
ApocrineDucts open into hair follices
ApocrineThe organic molecules in it decompose with time - odor
Modified apocrine glandsCeruminous – secrete earwax
Modified apocrine glandsMammary – secrete milk

Section 3

Question Answer
Thermoregulationsweat glands are distributed throughout the integumentary system to assist in cooling the body off in homeostasis
Vitamin D Synthesisusing sunlight, the skin is capable of creating Vitamin D for the body
Protectionprovides a barrier to fluid loss from the body; intact skin prevents the entry of microorganisms into the body; melanin absorbs UV, preventing harm to layers below
Absorptionthe skin can absorb topical medications
Sensationworking with the nervous system, skin can sense pain, touch, temperature, vibration, and pressure
Secretionwater, oil, salt, and small amounts of waste can leave via the skin

Section 4

Question Answer
First-degree burnepidermis only; redness
Second-degree burnepidermis and dermis, with blistering
Third-degree burnfull thickness, destroying epidermis, dermis, often part of hypodermis
Third-degree burnOver 10% of the body
Second-degree burn25 % of the body
Aktinic keratosispremalignant
Basal cellcells of stratum basale
Squamous cellkeratinocytes