Exam #2 Chapters 5, 6, and 8 Flashcards
Dermis functions
Gives structural strength.
Connective Tissue with many fibers, fibroblasts, macrophages. Some adipocytes and blood vessels.
Contains nerves, blood vessels, hair follicles, smooth muscles, glands, and lymphatic vessels.
sensory functions of dermis
pain, itch, tickle, temperature, touch, pressure, two-point discrimination
how many layers of dermis. name the layers.
2 layers!
papillary layer
reticular layer
papillary layer of dermis
named for dermal papillae
attaches epidermis to dermis
nourishes the epidermis
consists of areolar tissue
contains: capillaries, lymphatic capillaries, sensory neurons
reticular layer of dermis
meshwork of DENSE IRREGULAR CT
COLLAGEN FIBERS (extend into papillary layer and hypodermis)
Structural strength and support
Elastin fibers
Allows for elasticity and stretch
Contains similar structures as papillary layer BUT ALSO SWEAT GLANDS AND HAIR FOLLICLES
Lines of cleavage, describe.
Formed by arrangement of collagen and elastin fibers in skin.
Significant for SURGERY and WOUND HEALING
Parallel to cleavage: better healing and less scarring Perpendicular to cleavage: remain open and more scarring.
Hypodermis
Separates skin from deeper structures.
Stabilizes skin to underlying tissues.
Allows independent movement.
Dominated by adipose tissue
Storage of energy
In men (accumulation): neck, arms, lower back, buttocks
In women: breasts, buttocks, hips, thighs
Both men/women: few cells on back of hands/surfaces of feet, more in abdominal region
Accessory Structures of Integumentary System
Sensory receptors
monitor external environment
Hair and hair follicles
produce hairs that protect skull
produce hairs that provide delicate touch sensations
Exocrine Sweat Glands
assist in thermoregulation
excrete wastes
lubricate epidermis
Nails
protect and support tips of fingers and toes
ACCESSORY STRUCTURES
sensory receptors (of integumentary) function
monitor external environment
ACCESSORY STRUCTURES
Hair and hair follicles (integumentary) function
produce hairs that protect skull
produce hairs that provide delicate touch sensations
ACCESSORY STRUCTURES
Exocrine Sweat glands (integumentary) function
thermoregulation
excrete waste
lubricate epidermis
ACCESSORY STRUCTURES
Nails (integumentary) function
protect and support fingers and toes
Epidermis
what are the skin sensory receptors located here?
Dermis
what are the skin sensory receptors located here?
EPIDERMIS
merkel cells
tactile discs (monitor epidermis)
free nerve endings
DERMIS
more specialized receptors
tactile corpuscles (in dermal papillae)
lamellate corpuscles (in reticular layer)
Merkel cells found in ________ layers of where?
Merkel cells found in DEEP layers of EPIDERMIS.
(skin sensory receptor)
free nerve endings
(epidermis skin sensory receptor)
extensions for pain and temperature
tactile corpuscles
(skin sensory receptor of dermis)
detect light touch
located in dermal papillae
lamellated corpuscles
(skin sensory receptor of dermis)
deep pressure/vibration
located in reticular layer of dermis
“lamellated” or “layers” - structure
protection… protection against what?
(integumentary system)
against UV light, microorganisms, water loss.
what kind of sensations?
(integumentary system?)
sensory receptors for temperature, touch, pressure, pain.
regulation… regulation of what?
(integumentary system)
temperature regulation
production… production of what?
(integumentary system)
vitamin D production
excretion… excretion of what?
(integumentary system)
very SMALL amount of waste product
Body’s first line of defense against environment?
Integument! (or skin)
2 major components of integumentary system are what?
cutaneous membrane
accessory structures
cutaneous membrane layers
epidermis
stratified squamous epithelium
dermis
papillary layer (areolar CT)
reticular layer (dense irregular CT)
*hypodermis - NOT PART OF SKIN, WHY ITS CALLED HYPODERMIS, IT’S BELOW THE DERMIS, OR SKIN. Not a cutaneous membrane. Not part of integument. I repeat, NOT a part of the integument. Separates integument from deep fascia. Helps hold body together. Areolar loose CT and adipose tissue.
Cutaneous plexus is what
network of blood vessels throughout the dermis
epidermis… vascular or avascular
avascular.. nourished by diffusion from CAPILLARIES OF PAPILLARY LAYER of DERMIS. No direct blood supply.
Epidermis is dominated by these epithelial cells
KERATINOCYTES
Epithelial cells are constantly produced in _________. Are shed at __________.
deepest layers, exposed surface.
Another word for “layers”
“strata”
Most of body covered with how many strata?
4 strata (thin skin)
THICK SKIN HAS 5 (stratum lucidum)
Skin is thickest where?
Palms of hands and soles of feet
Dermal papilla function
Increase the surface area between epidermis/dermis. Why? Attachment and diffusion of nutrients to the AVASCULAR epidermis.
Your fingerprints are what?
Your dermal papilla. NO TWO PEOPLE HAVE THE SAME FINGERPRINTS!!! PERIOD. NOT EVEN IDENTICAL TWINS.
Fingerprints and footprints are your thick skin. They are a representation of your _______.
Dermal papilla.
Increase in number of layers in stratum corneum..
callus. when this occurs over a bony prominence, a CORN forms.
What is the protein that makes cells waterproof?
(integumentary system)
keratin! keratinocytes produce keratin for strength. once a cell is keratinized, it can’t do anything. its waterproof, can’t exchange fluid, ions, waste… it dies.
Epidermal cell type that is part of the immune system
langerhans cells, phagocytic cells that patrol epidermis for pathogen entry.
COME LET’S GRAB SOME BEER!!! (mnemonic)
Corneum, lucidum, granulosum, spinosum, basale
Stratum corneum (means horn)
outermost layer
15-30 layers - keratinized cells filled with keratin
dead cells still attached to desmosomes
stay in stratum corneum - 2 weeks before shed
stratum lucidum (means clear)
absent in thin skin
separates corneum layer from underlying layers
flattened dead cells filled with keratin AND KERATOHYALIN
Stratum granulosum
3-5 layers keratinocytes
living cells stopped dividing, started making keratin and keratohyalin
protein fibers develop, membranes become less permeable
Stratum spinosum
8-10 layers of live keratinocytes bound by desmosomes. In microscope slides, CELLS LOOK SPINY.
Where dendritic cells (immune system cells) ARE FOUND. Defends against pathogens/SUPERFICIAL CANCERS
Stratum basale
actively DIVIDE.
Merkel cells found here.
Dandruff is what layer of strata being shed from the outer layers of skin of the scalp?
stratum corneum
A splinter in the top of the hand penetrates the third layer of skin…. what layer has it penetrated???
SPINOSUM!!! Question says, “top of hand” not “palm of hand” - therefore there are only 4 layers in the top of the hand. No stratum lucidum (palm of hand or sole of foot would have 5 layers).
Presence of pigments of skin are influenced by
melanin and carotene
palms are thick with keratin but have LESS melanin, that’s why…
someone who has dark skin has lighter colored palms as opposed to rest of body…
melanin is manufactured from
amino acid TYROSINE.
Melanocytes are only found in the stratum
BASALE
Melanocytes package up the melanin in a vesicle called a _______, and releases it by ___________.
Keratinocytes take up the ________ by _________.
melanosome, exocytosis.
melanin, ENDOCYTOSIS.
Sunlight damages collagen. Melanin is natural sunscreen. Dark skinned people have more natural sunscreen. That’s why…
Morgan Freeman still looks great at 118 years old…
Melanin uptake and storage by keratinocytes
The melanosome is digested via endocytosis and releases melanin. The melanin do something special, they surround the nuclei of your KERATINOCYTES and shield the nucleus from UV radiation with your melanin, nature’s SPF.
Hair on body found EXCEPT
palms of hands/toes, lips, external genitalia
how many hairs on body
2.5 million (about)
what percentage of hair is on body (not head)
75%
Two types of hair, describe them
- terminal hairs: large coarse, darkly pigmented hairs such as on head, armpits, groin
- vellus hairs (smaller, shorter, delicate on general body surface
A hair follicle is composed of what tissues
epithelial tissue and connective tissue
difference between hair shaft and hair root
hair shaft is the exposed part of the hair to the environment, but it DOES extend beneath the skin. the hair root is the ANCHORING portions where growth occurs.
what is a root hair plexus
a root hair plexus is a network of sensory nerves that surround the BASE of the hair follicle.
talk about the arrector pili muscle
it is a smooth muscle that pulls on the follicle causing the hair to stand erect. Responsible for “goosebumps”
Internal root sheath
(layers of the hair follicle)
surrounds hair root; deepest layer, superficial to cuticle
External root sheath
(layers of hair follicle)
runs the entire length of the follicle
Glassy membrane
(layers of the hair follicle)
thick, clear, basal lamina
connective tissue sheath
(layers of the follicle)
outermost layer
Base of hair follicle is called ____ and has _____?
base has HAIR BULB (epithelial cap) and HAIR PAPILLA (peg of connective tissue with blood vessels and nerves)
layers of the hair shaft
cuticle (outermost layer made of KERATIN)
cortex (middle layer with HARD KERATIN for stiffness)
medulla (core with flexible SOFT KERATIN)
Talk about the “active phase” and “resting phase” of hair growth
ACTIVE PHASE
hair grows 2-5 years at .33mm per day
variation in growth rate/cycle duration varies from person to person
RESTING PHASE
follicle regresses and enters
hair loses attachment tothefollicleand becomes_a CLUB HAIR
CLUB HAIR is shed as follicle reactivates - replacement hair growth begins
What is responsible for hair color?
differences in structure and variation in pigments produced in melanocytes at hair papilla
*different forms of melanin for different hair colors
Pigments produced in melanocytes __________ with age.
DECREASES!
White hair lacks pigment and has air bubbles in medulla.
Sebaceous glands, aka_______. Talk about them.
They are OIL GLANDS.
More specifically, the are holocrine glands that discharge an oily LIPID secretion. Lipids are fats and oil is fat.
They are simple branched alveolar glands that secrete onto one hair follicle.
Contractions of arrector pili muscle cause the release of SEBUM onto the hair follicle and skin surface.
What is sebum? Describe it.
Sebum is a mixture of triglycerides, cholesterol, proteins, and electrolytes.
Sebum LUBRICATES the hair shaft and is ANTIMICROBIAL
Merocrine secretion “mero” means “pure” in LATIN, pure water?
Merocrine glands produce watery secretion. They are sweat glands. Their myoepithelial cells (“myo” meaning muscle) squeeeeeze the gland to discharge secretion..
Their functions to wash the epidermal surface.
There is another type of sweat gland…. can you think of it?
Another type of sweat gland. Not a merocrine sweat gland. What is it called and talk about it.
Apocrine sweat glands!
Not found everywhere! Only in armpits (axillae), groin, and nipples.
They produce a viscous secretion with a COMPLEX composition.
They can communicate olfactory information with their PHEROMONE PRODUCTION.
Strongly influenced by HORMONES.
INCLUDES THE CERUMINOUS GLANDS AND MAMMARY GLANDS
*How to identify? Their DUCT merges with the hair follicle!
Detailed information on ECCRINE/MEROCRINE sweat glands
Found in MOST areas of skin. Not armpits, groin, or nipples!
Produce watery secretions with electrolytes.
Controlled primarily by NERVOUS SYSTEM.
Important in THERMOREGULATION and EXCRETION
SOME*** antibacterial action
Duct opens onto the body surface… we call that a PORE
Detailed info about NAILS. Talk about the nails.
Nails protect the exposed DORSAL surfaces of tips of fingers and toes.
They help limit distortion of digits under physical stress.
Are composed of dead cells packed with keratin.
Can be affected by conditions that alter body METABOLISM.
(If your metabolism gets f’d up, the condition of your nails can be an indication)
EX: diagnostically, if we see nails that are pitted and distorted… it could be that the person has PSORIASIS.
EX: diagnostically, if we see nails that are concave, the person could have a BLOOD DISORDER.
nail structure. what is the main part? talk about it.
The main part of the nail is the NAIL BODY.
It is bordered by LATERAL NAIL GROOVES (depressions) and LATERAL NAIL FOLDS (ridges).
The nail body covers the NAIL BED (the underlying epidermis).
The LUNULA is the pale, proximal part of the nail body.
What is the nail root? Talk about it.
The nail root is the epidermal fold where NAIL PRODUCTION OCCURS.
What is the eponychium? AKA THE ________?
What is the hyponychium?
The “eponychium” (“epi” - over, “onyx” - nail)
the portion of the stratum corneum of the nail root that extends over the nail. AKA THE CUTICLE.
The “hyponychium” is the area of thickened stratum corneum under the free edge.
Getting older… what are the age-related changes in SKIN!!!
Fewer melanocytes.
Thinning, drier epidermis.
Thinning dermis.
Diminished immune response.
Decreased participation.
Reduced blood supply.
Slower skin repair.
Fewer active follicles.
Altered hair and fat distribution.
ratio of melanocytes to basal cells varies by body region. give two ratios
1:4 over most of body
1:20 over palms of hands, soles of feet
The actual NUMBER of melanocytes does not dictate the differences in
SKIN COLOR
malignant melanoma extremely invasive due to extensions of _______. and if they extend into the dermis, you’re in really bad shape.
dendrites; dendritic extensions.
Carotene is what vitamin?
A. Orange VEGETABLES, NOT FRUIT. I REPEAT, NOT FRUIT.
Ingest extra carotene, will invade your fat cells. Accumulates in epidermis and fatty tissues of hypodermis. Vitamin A is a oil-based vitamin. Why you can store them in your body more easily if you have more fat, or adipose tissue. Can reach toxicity.
Why you look orange.
More hemoglobin in your red blood cells =
Skin looks more pinkish. Hemoglobin varies with amount of oxygen binding.
More oxygen binding, bright red. Less oxygen: dark red.
Appears blue (cyanosis) an indicator of poor blood supply. Can be seen in thin skinned areas.
Dilation or constriction of dermal blood vessels can affect
blushing… observed skin coloration. Or if you turn very pale, constriction.
UV Radiation stimulates
Stimulates melanocytes to produce more melanin
skin cancers start in the
epidermis. if they metastisize, they spread into the dermis.
constant sun exposure can increase your risk.
Basal cell carcinoma
most common skin cancer. Most people survive, due to UV radiation. Virtually no metastasis.
Second most common type of skin cancer
Squamous cell carcinoma
Deadly if untreated
Malignant melanoma
cancerous melanocytes, metastasize through lymphatic system. Detected early, 5-year survival rate. If caught late, survival rate 5-10%.
conditions affecting skin color
albinism - genetic mutation causes lack of melanin production or melanin that is extremely light in color.
vitiligo - loss of melanocytes usually due to an autoimmune response those areas of no melanocytes are unprotected from UV radiation.
alopecia - loss of hair.
name two pigments contained in the epidermis
hemoglobin and melanin
why does the skin of a fair-skinned person appear red during exercise in hot weather?
vasodilation
what condition would occur if a person did not produce melanin?
vitiligo, albinism, gray or white hair
Marfin’s syndrome
Disorder of body’s production of collagen fibers and elastic fibers. Your skin just “hangs” on you. You have a weak aorta, your joints are abnormally long. Affects the structure of your entire body.
Merkel cells are what type of touch?
fine touch
tactile corpuscles
go up in to the dermal papillae!!! (epidermis)
… but they are anchored from down in the dermis
(SO BOTH EPIDERMIS AND DERMIS)
vellus hair
think “velvet”, soft finer hairs as opposed to the much coarser, thicker, terminal hairs.
in a hair follicle the epidermis (stratum basale) is actually dipping down into the
DERMIS, where it extends down with the hair bulb, because the root of the hair is alive. The rest of the hair is dead. So, the follicle is alive, everything else is dead.
What coordinates integumentary system function with OTHER systems?
(Endocrine functions - integumentary system)
HORMONES
Glucocorticoids are another name for
Steroid hormones