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What are tissues?
groups of cells with similar structure and functions
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What are the 4 primary types of tissues?
- Epithelium: layers/cells of your skin, inside layers of digestive respiratory and excretory systems
- Connective Tissue: connects epithelium to the organs ex- skin to muscles
- Nervous Tissue: brain and white matter
- Muscle tissue: tissue for muscles (skeletal muscles, cardiac muscles, smooth muscles)
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Where are Epithelial tissues found?
body converings, body linings, glands/glandular tissue
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What are the functions of epithelial tissues?
- protection from different things
- ---> ex- sunlight, invaders (bacteria), acids, bases
- absorption
- ---> small intestine, stomach, and alveoli in lungs
- filtration: epithelium filters out different things such as urine
- secretions
- ---> sweat
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What are epithelium characteristics?
- cells very close together, no space between them
- tissue layer is always exposed to one free surface (ex. alveoli exposed to hollow opening in lungs)
- the lower surface is bound to a basement membrane
- avascular (have no blood supply)
- can regenerate easily if well nourished
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For classification of epithilium, what are the names that determine the number of cell layers?
- simple: one layer
- stratified: more than one layer
- pseudostratefied: fals stratefied layer, looks like many layers but is one
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For classification of epithelium, what are the names that determine the shape of the cell?
- squamous: flattened
- cuboidal: cube shaped
- columner: column like
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Describe single cubodial
- singel layer of cube like cells
- common in glands and their ducts
- forms walls of kidney tubules
- covers the ovaries
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What are the two major parts of the skin?
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What are the 8 functions of the integumentary system?
- 1. It is an impermeable membrane- doesn't allow things in or out, advantage of this is it doesnt let water out, keeping you hydrated
- 2. insulates and cushions the deeper organs
- 3. protects against mechanical damage ( bumps & cuts)
- 4. protects against chemical damage (acids and bases) ( secretions on your skin are slightly acidic so it can neutralize slight bases)
- 5. protects against thermal damage (heat and cold, like frostbite) and ultraviolet rays (like a sunburn)
- 6. excretion (through your sweat you get rid of urea, salt and water)
- 7. manufactures/makes protiens for immunity and vitamin D (sunlight helps this)
- 8. contains nerves that sense pain, touch, pressure, hot and cold (all different receptors)
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What is the Epidermis?
- made up of stratified squamous (many flat layers squished) epethilium
- Divided up into 5 layers
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What are the 5 layers of the epidermis? from outermost to innermost
- Stratum Corneum
- Stratum Lucidum
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
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The first two layers of the epidermis are...
dead cells because the nutrients can't diffuse far enough to keep them alive
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Explain the stratum corneum
- top layer
- made up of 20-30 layers of cells
- 75% of all the layers of your skin is stratum corneum
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Explain Stratum Lucidum
- dead clear cells and can easily be seen in the palms of your hand and soles of your feet (thicker in these areas)
- 2nd layer
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Explain stratum granulosum
- some alive cells, some dead (transition)
- filled with keratin (a protien) that fills up the layers above it (lucidum and corneum)
- keratinocytes die
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Explain Stratum Spinosum
- single layer of cells
- cells are alive
- recieves neutrients to stay alive from stratum basale
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Explain Stratum Basale
- also called germinativum
- stem cells that become the other cells
- only layer that recieves nutrients directly from the blood (those nutrients diffuse into the spinusom and some granulosum which keeps them alive)
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How are all the layers connected?
the cells move up. basale become spinosum which mature into granulosum then die and become lucidum which flake off as corneum
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Do blood vessels touch the epidermis?
yes but only at one point to deliver neutrients
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How many skin cells are produced a day?
- millions
- btween 25 and 45 days ALL of your skin cells are replaced
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What are keratinocytes?
cells in the epidermis that make keratin
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What is keratin?
a protien that protects the dna of the neucleus
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What is melanin?
- a pigment that ranges from yellow to brown to black
- can determine skin color
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What is the dermis?
- below the epidermis
- made up of dense connective tissue
- vascular region
- major skin area where derivatives (hair, nails) reside
- when tanned becomes leather, provides mechanical strength to the skin
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What are the 2 regions of the dermis?
- papillary region
- reticular region
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What is the Papillary Region/Layer?
uneven, fingerlike projections from the superior surface of the dermis
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What does the Papillary Region contain?
- capillaries that bring blood and nutriends to the epidermis
- pain receptors called free nerve endings
- touch receptors called meissner corpuscles
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How does papillae form your fingerprint?
papillae push up epidermis to make your fingerprint, see drawing
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Can two people have the same fingerprint? Twins?
no. not even twins. in the mothers womb, fluid moves around moving one twins fingerprint one way and the others the other way
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What is the Reticular layer? What does it contain?
- the deepest skin layer
- contains: blood vessels, sweat glands, and deep pressure receptors called pacinian corpuscles
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What does the reticular layer also contain?
- collagen fibers
- elastic fibers
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What are collagen fibers?
- make the dermis very tough, not easily broken
- little pieces of protien that hold it together
- it binds to water to keep your skin hydrated
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What are elastic fibers?
allow the skin to stretch and then return to its orignial place
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Thanks to the collagen and elastic fibers, the skin is...
stretchy but strong
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What is a blister?
forms when the dermis and the epidermis separate. they pull apart and the space between where they should meet is filled with fluid
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What is the hypodermis?
- NOT part of the skin
- below the dermis
- layer filled with fat and connects the dermis to the organs underneath
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What controlls skin color?
- 3 pigments
- --->melanin
- --->carotene
- --->hemaglobin
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What is melanin?
- yellow, reddish brown, or black pigment in epidermis
- --->freckles or moles are collections of melanin
- most melanocytes are found in the stratum basale
- most responsible for the color of dark skinned people
- provides a natural sunscrene
- phagocytized by keratinocytes
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What is Carotene?
- orange to yellow pigment in the stratum corneum (1st layer)
- provides an orange cast to skin
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What is Hemoglobin?
- a red to maroon color, depending on the oxygen level
- inside of RBCs in your blood vessels
- most responsible for the skin color of caucasions
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The three pigments.....
combine to make your skin color
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What can influence skin color?
- emotional stimuli
- --->can also indicate illness
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What are the different skin colors that are influenced?
- Redness or Erythema
- Pallor or blanching (turning white)
- Jaundice (yellow)
- Bruises or black-and-blue marks
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Explain Redness or Erythema
this can occure if you're embarrassed, if you have a fever, hypertension (high blood pressure), inflammation, or allergy
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Explain Palor or blanching (turning white)
from fear or anger, anemia (lacking iron and having trouble moving oxygen or bloodflow is restricted to an area)
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Explain Jaundice (yellow)
usually a signal of liver disease, excess bile is absorbed in the blood
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Explain Bruises or black-and-blue marks
where blood has escaped the circulatory system and fills a tissue place called a hematoma (or bruise). can indicate a deficiency of vitamin C if you pruise easily. can also indicate hemophilia
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What are the Appendages of the skin?
- Cutaneous glands
- Hair/Hair Follicles
- Nails
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What are cutaneous glands?
- glands in the skin
- all exocrine (they have a space and a tube or duct leading to the surface)
- two groups
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What are the two groups of cutaneous glands?
- Sebaceous Glands
- Sweat Glands
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What are sebaceous glands?
- secrete oil that covers all parts of the skin escept the souls of your feet and palms of your hands
- keeps skin soft and prevents it from becomming brittle
- produces antibacterial chemicals to fight infection
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What are Sweat Glands?
- produce sweat
- approx 2.5 million glands in the body
- 2 types
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What are the two types of sweat glands?
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What are eccrine glands?
- produce a clear liquid made up of water, salt, vitamin c, and matabolic waste such as urea, uric acid, ammonia and lactic acid
- maintains body temp
- pH between 4 and 6 (acidic) helps burn through membranes of harmful bacteria
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What are apocrine glands?
- found in the axillary area (armpits) and genital areas
- secrete fatty acids and protiens which color it yellow or a clowdy milky white
- sweat is colorless and odorless unless bacteria are living on the secretions (this is B.O.)
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What is the function of Hair?
- protection from bumps
- shields eyes from dust and particles
- keeps out particles from the respiratory sysem (nose hairs)
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What is the structure of hair?
- hair is made up of dead cells
- bottom part is alive until you die
- dead cells build up over time making your hair grow longer
- has 3 layers
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What are the 3 layers of hair?
- medulla: inner layer
- cortex: middle layer
- cuticle: outside, single layer that overlaps and prevents dehydration
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What are the shapes of the shafts of the hair? What do they signify?
- oval shaft: hair will be smooth, silky, and usually wavy
- flat or ribbon like shaft: curly or kinky hair
- round shaft: straight and course
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What are arrector pilli?
muscles that contract to make hairs stand on end (goosebumps)
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What are nails?
scale like epidermal cells
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What do nails have?
a root that is embedded into the skin, also dead cells except for root which is alive
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Why do nails appear pink?
they are colorless but appear pink because of the blood vessels beneath
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What are the Homeostatic imbalances of the skin?
- Athlete's foot
- Boils and carbuncles
- Cold sores
- Contact dermatitis
- Impetigo
- Psoriasis
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What is athlete's foot?
- itchy red impealing skin
- usually between the toes
- fungus
- it would be easier to treat if it was a bacteria b/c fungi cells are similar to your own so you have to kill some of your own cells to get rid of it
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What are Boils or Carbuncles?
- inflammation of the follicles and sebaceous glands
- caused by a bacterial infection, usually staffaureus
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What are Cold Sores?
- also called fever blisters
- itchy and stingy
- fluid filled blisters caused by herpes simplex virus
- activated by uv light, fever, or emotional upset
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What is Contact Dermatitis?
- itchy redness and swelling of the skin that turns into blisters
- caused by exposure to chemicals that cause an allergic reaction (ex- poison ivy)
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What is impetigo?
- pink water filled spaces or cracks that develop a yellow crust on the outside and eventually burst
- caused by staff
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What is Psoriasis?
- chronic red epidermal legions covered by dry slivery scales
- unknown cause
- can be triggered by trauma, infection, hormonal change, stress
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What happens when your body temperature rises?
eccrine glands become active
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What is the least malignent and most common cancer?
basal cell carcinoma
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Accumulations in the sebaceous glands of an infant that appear as small white dots on the skin are
milia
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Squamous cell Carinoma
Skin cancer that appears most often as scaley, reddened papule that gradually form a shallow ulser with a firm raised boarder
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A chronic condition characterized by reddened epidermal leasions is...
Psoriasis
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What is the matrix?
growth zone at the inferior end of a hair follicle
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What is a decubitus ulcer?
medical term for a bedsore
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What is the root?
the part of hair that is enclosed in a follicle
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What is languo?
- downy type hair that covers a fetus during the 5th and 6th months
- is shed at birth
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What is the medulla?
central core of hair
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What is the Dermal sheath?
Outermost covering of hair follicle
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What is the basement membrane between?
epithelial and connective tissue
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What imbalance is caused by a virus?
cold and sores
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If a person has a severe burns, the two most life threatening concerns are...
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What is the function of muscle tissue?
contraction to produce movement
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What is the function of Nervous Tissue?
irritability and conductivity
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What is the function of connective tissue?
- protection
- support
- binds body tissues together
- usually well vacularized and has extensive intercellular matrix
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Function of epithileal tissue?
- protection
- absorption
- filtration
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What else does does keratin do?
prevents the skin from soaking up moisture like a sponge
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What are fingernails?
a modification of the epidermis
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Which layer of the skin insulates deeper tissues from extreme temperature changes that occur outside of the body
subcutaneous (hypodermis) connective tissue
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What is the first threat to life from a third degree burn
dehydration
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What type of tissue is found int hte walls of blood vessels?
smooth muscle tissue
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What is not connective tissue?
Skeletal, smooth, and cardiac muscle tissue
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Where are pain and touch receptors found?
the dermis
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The skin is a...
cutaneous membrane
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What is adipose tissue?
- fat tissue
- forms subcutaneous connective tissue beneath the skin
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What is acne?
inflammation of the sebaceous glands
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Where are interculated disks found?
cardiac muscle tissue
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Where are appocrine glands found?
axillary and genital areas
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Where are melaninocytes found?
stratum basale
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Tanning effect is productive due to
an increased amount of melanin
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Glands such as thyroid, that secrete their products directly into the blood are
endocrine
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What part of the skin has no blood supply of its own?
epidermis
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Which layer has dermal papillae
papillary
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