Chapter 10 Physiology and Histology of the Skin
Stratum Corneum
horny layer, top layer of skin, 15-20 layers of cells. keratinocytes are squamous and cornified
What is not an element of the skin's acid mantle
blood
What are eccrine glands
sweat glands
What cells identify molecules that have foreign peptides, and help to regulate immune response
t cells
What is glycation
the binding of a protein molecule to a glucose molecule
Keratinocytes
composed of keratin, 95 percent of epidermis
Tyrosinase
enzyme that stimulates melanocytes and thus produces melanin
What are keratinocytes
epidermal cells composed of keratin, lipids, and other proteins
What hormone stimulates cells to reproduce and heal
epidermal growth facor
What does the skins barrier function protect us from, in addition to irritation
intercellular water loss
What glands help regulate the body's temperature?
sudoriferous glands
What are follicles
tubelike openings in the epidermis
What is the dermis
support layer below the epidermis
Stratum Germinativum
Basal Cell layer, 5th layer of epidermis, stem cells (mother cells) undergo mitosis. Melanocytes are here
How does skin get its nourishment?
Blood and Lymph
What are the items in the dermis that respond to touch, pain, cold, heat, and pressure?
sensory nerve endings
What are most abundant in the fingertips, as opposed to other parts of the body
sensory nerve fibers
define afferent nerves
sensory nerve, nerve fibers send messages to central nervous system and brain to react to heat, cold, pain, pressure, and touch
Where in the body is hyaluronic acid found
skin
What does barrier function mean?
skins way of protecting from irritation caused by TEWL
Stratum Spinosum
spiny layer, 4th layer of epidermis lipids, proteins, and desmosomes formed here Langerhans immune cells are here
What function does the enzyme tyrosinase perform
stimulates melanocytes and thus produces melanin
What part of the skin provides a protective cushion and energy storage for the body
subcutaneous layer
What are the glands that excrete perspiration, regulate body temperature, and detoxify the body
sudoriferous
What causes skin cells built in antioxidants to lose their ability to protect cells
sun exposure
Onyx
technical term for nail
Dermis
thickest layer of skin, called derma, corium, cutis, or true skin; support layer of connective tissues below the epidermis
Stratum Granulosum
third layer of epidermis; granular layer; production of keratin and intercellular lipids takes place here enzymes desolve desmosomes form skins waterproofing barrier function
Why does the body perspire
to protect us from overheating
What forms skins waterproofing barrier function?
triglycerides, ceramides, waxes, fatty acids, and intercellular lipids excreted from cells in stratum granulosum
Where in the body are the coiled structures known as apocrine glands found
underarm and genital area
What is the acid mantle
Protective layer of lipids and secretions on the skin's surface
What are the two main glands associated with the skin?
Sebaceous Glands; Produce oil - connected to hair follicles Sudoriferous Glands; excrete sweat...
What are the six main functions of the skin?
1. Protection-outside elements - bacteria 2. Sensation 3. Heat Regulation- sweat glands and blood flow 4. Excretion- sweat glands detoxify 5. Secretion- sebum protects the skin surface 6. Absorption- of ingredients, water, & O2 for skin's health
Name the five layers of the epidermis
1. Stratum Corneum 2. Stratum Lucidum 3. Stratum Granulosum 4. Stratum Spinosum 5. Statum Germinativum
How many times thicker than the epidermis is the dermis, approximatley
25
What is the average internal temperature of the body in degrees fahrenhiet
98.6
What are the two types of sweat glands (sudoriferous)?
Apocrine - attached to hair folicle found in arm pit and genital area Eccrine- found all over body
What causes the body to produce its own vitamin D
Exposure to the sun
What is rue of the reticular layer of the skin
It is the deepest layer of the dermis
What is true of the epidermis
It is the outermost layer of the skin
What are keratinocytes?
Keratin cells that contain protein and lipids. Protect from water loss and dehydration
What are guard cells of the immune system that sense unrecognized foreign invaders, such as bacteria
Langerhans immune cells
Name the two main types of nerves and describe what they do?
Motor; convey impulses from the brain to muscles or glands Sensory; send message to central nervous system to react to heat, cold, pain, pressure, and touch
Name the two layers of the dermis
Papillary and reticular layers
What are the names of two layers in Dermis
Papillary layer Reticular Layer
Two types of melanin
Pheomelanin- red to yellow in color Eumelanin - dark brown to black
Why is the skin elasticity important
The skin has to be elastic so that it can expand and contract, be strong so that it can protect the body and it must be able to repair itself.
Describe the difference between UVA wavelengths and UVB wavelengths
UVA are ageing and long UVB are Burning and short in length...
How does UVA and UVB radiation affect the skin?
UVA cause genetic damage and cell death UVB causes burning of the skin & contributes to synthesis of Vit D
Why is UVB radiation also known as burning rays?
UVB wavelengths cause burning of the skin as well as cancer
Where in the skin is the stratum germinativum located
above the papillary layer of the dermis
What is another name for subcutis tissue
adipose tissue
What is a common term for UVA radiation
aging rays
What function do desmosomes perform
assist in holding cells together
What is the common name of the stratum germiniativum
basal layer
subcutaneous tissue
below reticular layer, loose connective tissue or adipose tissue. protective cushion that gives contour and smoothness to the body, as well as providing a source of energy for body.
What are corneocytes
hardened kertatinocytes
What causes telangiectaisa
capillary damage
What are melanocytes?
cells that produce pigment granules in the basal layer
What are melanocytes
cells that produce skin pigment granules in the basal layer
Where in the face does the chronic condition rosacea primarily appear
cheeks and nose
What are free radicals?
chemically active atoms or molecules with unpaired electrons. Unequal number of electrons and unbalanced charge.
Melanin
complex protein which determines skin, eye, and hair color
What are hair papillae
cone shaped elevations at the base of the follicle
define nerves
cordlike bundles of fibers made of neurons where sensory stimuli and motor impulses pass
telangiectasia
couperose skin, the dilation of capillary walls
What is the common name for the stratum corneum
horny layer
What causes injured skin to restore itself to its normal thickness
hyperproduction of cells
What is another name for the subcutaneous layer of the skin
hypodermis
What are membranes of ridges and grooves that attach to the epidermis
dermal papillae
Where in the skin are lymph vessels located
dermis
What protein fiber is found in the dermis and gives skin its flexibility and firmness
elastin
What causes transepidermal water loss
evaporation
Keratin
fiberous protein provides resiliency and protection to the skin, found in all layers of the skin
What performs the function of stimulating cells, collagen, and amino acids that form proteins
fibroblasts
elastin
fibrous protein that forms elastic tissue and gives skin its elasticity
What is collagen
fibrous tissue made from protein
define extracellular matrix in dermis
fluid matrix in dermis composed of collagen, proteins, and glycosaminoglycans. Maintains water balance, dermal support, and assist cell metablolism, growth and migration.
Merkel Cells, in basal layer
found in stratum germinativum layer; touch receptors (finger tips)
What are ceramides
glycolipid materials
What is the result of the contraction of the arrector pili muscle
goose bumps
What is the commonname of the stratum granulosum
granular layer
What is true of the stratum corneum
it is the outermost layer of the skin
What is true of the papillary layer of the skin
it is the top layer of the dermis
What forms the cells in the stratum granulosum that resemble granules
keratin
What is a fiber protein found in skin, hair, and nails
keratin
Desmosomes
keratin filaments, protein bods that create the junctions between the cells. Strengthen and aid in intercellular communication.
Desquamation
keratinocytes are shed from skin, happens on stratum corneum
squamous cells
keratinocytes on surface of stratum corneum, flat and scaly keratinized cells
define papillary layer of dermis
layer of dermis that connects the dermis to the epidermis, forming the epidermal/dermal junction
define Reticular layer
layer of dermis that is denser and deeper of the dermis, comprised of collagen and elastin
What protein determines hair, eye, and skin color
melanin
cell turnover
process of desquamation and replacement, happens on stratum corneum
define efferent nerves
motor nerve, fibers that convey impulses from brain or spinal cord to muscles or glands
What is true of sun exposure
of all factors, it has the greatest impact on how our skin ages
define sabaceous glands
oil glands, connected to hair follicles and produce oil, protects surface of skin
What is hydrolipidic film
oil water balance that protects the skins surface
What is the other type of melanin the body produces, besides eumelanin
pheomelanin
Melanosomes
pigmanet carrying granules that produce melanin
What are melanosomes
pigment carrying granules that produce melanin
What term do clients commonly use when referring to follicles
pores
Langerhans immune cells, in spiny layer
protect the body from infections by identifying foreign material
What is the acid mantle?
protective barrier of lipids and secretions on the surface of the skin
How does sebum protect the skin?
protective oil that keeps skin soft & protects from outside elements. Slows down TEWL
What is collagen?
protein substance of complex fibers that gives skin its strength & is necessary for wound healing
Collagen
protein substance of complex fibers that gives skin its strength and is necessary for wound dealing produced by fibroblasts
What is not one of the six primary functions of the skin
reflection
What protects the surface of the skin
sebaceous glands
What is not a compound in the body from which free radicals take electrons
sebum
What oil that provides protection for the epidermis from external factors and that lubricates both the skin and hair
sebum
Stratum Lucidum
second layer of epidermis, thin, clear layer of dead skin cells. Translucent layer Keratinocytes contain clear keratin thickest on palms and soles of feet; fingerprints and footprints
What comprises about 50 to 70 percent of the skin
water
Corneocytes
waterproof protective cells, hardened, in stratum corneum
When do free radicals produce more free radicals
while causing oxidation reactions