integumentary system Flashcards
what are the 4 main structures of which the body is composed of?
epithelial, connective, muscle and nerve
what are the subtypes of epithelial structure
- simple
- cuboidal
- columanr
- ciliated
- squamous
- compound
- stratified
- keratinised
- non-keratinised
- transitional
- stratified
what are the subtypes of connective structure
solid
-bone
-cancellous
-compact
-cartilage
-hyaline
-white fibre
-yellow elastic
semisolid
1.loose apeclar
2.white fibre
3. yellow elastic
4.adipose
5. lymphoid
liquid
-blood
-lymphwhat are the muscle subtypes
- smooth
- skeletal
- cardiac
what are the nerve subtypes
nerve
briefly describe the structure of epidermis
a special layer of epithelium
briefly describe the structure of the dermis
(aka. corium) comprised of vascular, dense connective tissue
describe the epidermal layers
stratum corneum stratum lucideum stratum granulosum stratum spinosum stratum basale(aka. stratum germinativum)
what is stratum corneum
comprised of many layers of keratinised dead cells that are flattened and nonnucleated; cornified… only layer that doesnt contain langerhan cells in the epidermis
what is stratum lucideum
thin, clear layer of epidermis that is only found on lips, palms and soles.
what is stratum granulosum
one or more layers of granular cells which contain fibres of keratin and shriveled nuclei
what is stratum spinosum
several layers of cells with centrally located, large, oval nuclei, and spine-like processes ; limited mitosis
what is stratum basale
aka. stratum germinativum. singular layer of cuboidal cells in contact with basement membrane that undergoes mitosis; contains pigment-producing melanocytes
what are two special cells in the epidermis
- langerhan cells
- melanocytes
what are langerhan cells and what do they do?
langerhan cells are specialized dendritic cells, not epithelial cell. they have some characteristics of macrophages
- engulf invading microorganisms - migrate to lymph nodes to present to T-cells
what are melanocytes?
are specialized dendritic cells, not epithelial cells.
- they are found in and slightly below stratum basale and branch into stratum spinosum.
- they DO NOT keratinize
- they contain tyrosinase enzyme, which produces melanin
- distributes melanin to surrounding cells.
the appearance of epidermal layers is a result of….
the movement of epithelial cells from deep to superficial layers, from living to dead layers.
new cells are produced in which layer of the epidermis?
stratum germinativum/ basale(lowest epidermal layer)
what layer does keratinization occur in epidermis?
stratum granulosum(bottom of horny layer, but in middle of epidermis)
what does the nails grow from?
the matrix
deep wrinkles are caused by …
change in structure of collagen fibres
flat scaly epithelial cells are…
squamous epithelial cells
simple cuboidal cells are found…
kidney tubules and ducts of salivary glands
describe epidermal lipids(ceramides, squalene, cholesterol, fatty acids), their origin and how they work in function with the skin barrier.
the sebaceous glands secrete SEBUM which lubricates the skin and hair.
- sebum contains FA’s, cholesterol, and other lipids.
- Sebaceous glands originate in the dermis.
- Sebum plays a role in protection against invasion by microorganisms.
describe the process of keratinization
keratinization is the process where keratin replaces the normal living cytoplasm of the cell until it dies.
what is the function of keratin
keratin is a substance that contains nitrogen, amino acids, and some sulphur.
-its the fundamental substance of the skin and nails as well as the keratinised layers of the skin.
soft keratin occurs…
in the skin
hard keratin occurs…
in hair and nails
describe the structure of the dermis
- Papillary layer which contains sub-papillary plexus(supplies blood to stratum basale)
- reticular layer that is main fibrous bed of the dermis, made of coarse, dense fibres(mainly collagen w/ few intermingeled strands of reticulin and elastic fibres…Collagen fibres comprise 75% of fibres in the dermis.
describe papillary layer
lays in the top of the dermis and contains papillae(finger-like projections) that contain capillary loops, or nerve endings. it composed of a matrix with thin fibres in extensive network of fibres of collagen, reticulin and elastin fibres.
-contains sub-papillary plexus, which supplies epidermis with blood
describe reticular layer
main fibrous bed of the dermis, composed of coarse, dense fibres, that are mainly of collagen with few intermingled reticulin and elastin fibres
describe hypodermis
contains dermal-hypodermal vascular plexus, which supplies blood to the hair follicle
describe the nerves in the dermis
nerve endings reach the stratum basale(stratum Germinativum) and sense pressure and temperature.
- afferent nerves bring signals to CNS
- efferent nerves bring signals from CNS
what are corpuscles
nerve ending clusters that sense touch, pressure, vibration and temperature
what are some appendages in the skin of the dermis
sweat glands, sebaceous glands, hair follicles and erector pili muscles.
list some nerves in the dermis
meissner’s corpuscle, corpuscle of merkle, free nerve endings, pacinian corpuscle, corpuscle of ruffini
order of veins, nerve and artery in hypodermis
vein
artery
nerve
list the 8specialized cells in the dermis
histiocytes mast cells macrophage fibroblasts type I collagen elastin extracellular matrix reticulin
what are fibroblasts
fibroblasts are specialized cells in the dermis that are stimulated by tissue damage, additionally they produce collagen, and play a crucial role in inflammation, due to microbial invasion and wound healing.
what are macrophages?
specialized immune cells in the dermis that engulf invading microorganisms
what are mast cells?
specialized immune cells that secrete histamine, which induces an immune response.
what are chromatophores?
cells in the dermis that have been stained(pigmented)by nearby melanocytes.
what are histiocytes?
specialized immune cells in the dermis that produce reticulin(sub-group of collagen, that forms basement membrane)
-also performs typical functions of macrophages
what is extracellular matrix
semi-liquid substance secreted by fibroblasts. ECM is primarily composed of glycosaminoglycans(GAG’s), such as hyaluronic acid.
what is type 1 collagen
produced by fibroblasts. It functions to support protein that provides tensile strength
what is elastin?
produced by fibroblasts, provides elasticity
what is reticulin
produced by fibroblasts, and is a sub-group of collagen(type 3 collagen), which is more delicate than type 1 collagen.
-It forms the basement membrane and supportive framework for some organs
the apperance of the epidermis is the result of…
the movement of epithelial cells from deep to superficial layers, from living to dead.
what are sweat glands aka
sudoriferous glands
what are the two types of sweat glands
- eccrine
- apocrine
what are apocrine glands
type of Sudoriferous gland that empties into hair follicle
- sebum+sweat= ‘acid mantle’
- active in puberty
- profuse in areas with hair follicles;armpits, groin and scalp
- excrete greater proportions of lipids and waste products.
- skin bacteria act on the sweat to produce body odor
what are eccrine glands
type of sudoriferous gland that empties directly onto skin surface
- profuse in palms and soles
- functions to maintain proper body temperature
- secretes water, electolytes/salts and cellular waste products
describe sebaceous gland
aka. pilo-sebaceous unit.
- contains oily droplets(sebum)which are released into hair follicle as gland breaks down(holocrine secretion)
- lubricates skin and hair
- associated with hair follicles, but also on back, chest and face.
- max activity at puberty
- sebum contains FA’s, cholersterol, and other lipids and plays a role in protection again microbial invasion.
describe hair growth
it is determined by two factors:
- intrinisic(genetics and hormones)
- extrinsic(nutrition, age, drugs, health)
growth phases are:
anagen(active phase;longest phase; when you lose the hair)
catogen(dormant phase, when papilla and matrix seperate)
telogen(when papilla and matrix start to reconnect)
describe the structure of hair
- medulla(innermost)
- cortex(middle)
- Cuticle(outermost)
describe function of hair
to maintain homeostasis, maintain body temperature
how is pilo-sebaceous unit associated with hair
sebaceous glands are constricted from epithelium, their structure is closely related to hair follicle. therefore the hair follicle and sebaceous gland form pilo-sebaceous unit
-list hair types and indicate distribution. Discuss the composition and significance of the acid mantle and the pH of the skin
- *follicle shape determine texture
- straight
- wavy
- curly
- spiral coiled- *follicle size determines thickness
- thick or thin
- *acid mantle is formed from sebum and sweat glands and by the keratinization process… acid mantle(b/w 4.5 and 5.5) functions to prevent against bacteria.
- *follicle size determines thickness
what are the 8 functions of skin
- Sensation
- excretion(ex.sweat)
- secretion(ex. Sebum, vitamin d)
- prevents dessication
- physical barrier
- temperature regulation
- production of vitamin d
- absorption(limited)
list factors that affect skin thickness
- age
- genetic predisposition
- area of the body
- gender
what is telogen effluvium
often caused by serious stress, hair sheds for up to 6 months
anagen effluvium
shedding of hair during anagen phase(wrong phase), the shaft is narrow and breaks easily
androgenic alopecia
more common in men, basically just balding as you age
alopecia areata
loss of hair in circular pattern, surrounding hair is short and less pigmented
hair shaft breakage
caused by over-processing and skin infections
trichotillomania
deliberta twisting and pulling of hair, can lead to permanent hair loss.
describe common hair removal methods
non-permanent at the surface(shaving and depilartories)
non-permanent at the root(waxing, sugaring, tweezing, threading)
permanent at the root(LASER, IPL, electrolysis)
