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Chapter 5 Integument System (5.6 - Mechanism that produce Hair and…
Chapter 5 Integument System
Intro Integumentary
5.1 Epidermis
stratum granulosum
is composed of 3-5 layers of flattened granular cells (
filled with keratin
stratum germinative (basale)
the innermost layer of the epidermis
Directly under the basement membrane
composed of a single row mitosing cuboidal epithelial cells
Composed of melanocytes
stratum corneum
the outermost layer of the epithelial
composed of dead epithelial cells filled with protein keratin
stratum lucidum
translucent layer cells separating stratum corneum from stratum granulosum
extra layer only in thick skin of soles and palms
5.2 Skin Color
Environmental Factors
UV Rays
Chemicals
Drugs
Physiological Factors
Carotene mar accumulate in the s. corneum = orange
Hemoglobin (Hb) in dermal blood vessels = pink
Lack of Hb in dermal blood vessels = blue
Inability to break down Hb = yellow
Genetics
Melanin
DNA determines your race and the shade of your melanocytes
5.4 - Structure and functions of the dermis
Dermis
Inner layer of skin
\
binds epidermis to underlying tissues
Structure
Papillary layer (20%) is below the epidermis
Composed of loose areolar CT
Surface forms dermal papillae (finger light projections into the epidermis) that form fingerprints in thick skin
Meissner's Corpuscles (sensory receptors for light touch
Reticular layer (80%) dense irregular CT
Bundles of collagen fibers
elastic fibers and collagen fibers
Give skin strength and resiliency
Pacinian Corpuscles - sensory receptors for deep pressure
Main function - nourishment of epidermis
5.5 - Structures and functions of the Hypodermis
Subcutaneous layer
Beneath the skin
Structure
adipose tissue
Blood vessels
Function
insulation (temperature regulation)
5.3 - Interation between Vitamin D3 and Sunlight
Liver converts Vitamin D3 into Calcitrial
Vitamin D3 adds in absorption of calcium
weak and flexible bones without Vitamin D3
Skin Cancers
Basal Cell Carcinoma
A most commmon form of skin cancer
Originates in s. germinative
Squamos Cell Carcinoma
more superficial layers
Malignant Melanoma
Dangerous, usually begins as a mole
Metastasize thru the lymphoid system
Prevention
Avoid mid-day sun and wear sunblock
5.6 - Mechanism that produce Hair and Structural basis of Hair texture and color
Hair Follicles
Structure
Hair roots or base in deep dermis
Follicles throughout the dermis
Hair shaft
Cuticle - outer shingle like layer
Cortex - middle layer, flexible soft keratin
inner layer, hard keratin
Growth
grows for 2-5 years / new cycle pushes old hair old
0.3mm per day
2.5 million on body / 500,00 hairs on head
Keratinization
Cell are epithelium
cells in roots = active mitosis
cells in follicles = maturing and accumulating keratin
cells in epidermis = dead epithelial cells; full of keratin = exposed hair or hair shaft
Pigment
melanin decreases with age
genetically determined
white hair/ gray
Lack of melanin and air bubbles
Hair papilla
Peg of CT
nerves and capillaries
Arrector Pili
a bundle of smooth muscle associated with every hair follicle
causes hair to stand on end (goose bumps) when frightened or cold
5.7 - the various kinds of glands in the skin
Sebaceous glands
Merocrine
Structure
Coil in deep dermis
ducts in dermis
pore at surface
Characteristic
Respond to elevate temperature / exercise
No odor in secretion
Function throughout life
not asscoiated with hair follicles
Location
forehead
neck
Back
Secretion
99% water plus
salts
waste (urea and uric acid)
Apocrine
structure
ducts terminate into follicles
characteristic
responds to stress/emotions
odor in secretion
begin to function at puberty and continue through life
associated with hair follicles
location
armpit
groin
secretion
oil
cellular debris
modified endocrine glands
cerumonious glands
external ear
secretion: earwax
ceruman
Mammary Glands
breasts
secrete milk
Sudoriferous glands
Holocrine (simple cuboidal epithelial)
Associated with every hair follicle
secretion (holocrine) = sebum (i. e. oils)
fat
Cellular material
Sebum is secreted into hair follicles
function: sebum keeps hair and skin soft, pliable, and virtually waterproof
Disorders:
acne (hyper-secretion of sebum; ducts clog and inflame)
seborrhea (hyper-production of sebum; oily skin)
5.8 - Anatomical structure of nails
Nails:
Epithelium undergoing keratinization (active mitosis in lunala)
Function:
Manipulation
protection of digit ends
Structure:
nail body covers the nail bed
nail root
nail production by an epithelial fold
lunula: pale crescent near nail roots
cuticle
fold of stratum corneum
5.9 - How skin responds to injury and repairs itself
Temperature regulation, production and loss
Heat production is mostly a by-product of cellular metabolism
Heat Loss
is controlled by regulating dermal blood flow
vasodilation - increases dermal blood flow, which also increases heat loss
Vasoconstriction - decreases derma blood flow which decreases heat loss
Radiation
Most heat loss by this mode
Infrared heat rays move from area of high heat to areas of low heat
Conduction
less heat loss
heat moves by physical contact
the reason the seat you sit in is warm when you stand up
Convection
heat loss to surrounding air
increases our sweating
Healing Wounds and Burns
5.10 - Life span changes
Aging skin exhibits
Skin injuries and infections become more common
the sensitivity of immune system
muscles become weaker; bone density decreases
The skin becomes dry soft and often scaly
Hair thins and changes color
Sagging and wrinkles in the skin occurs
skin repairs slower