The Integumentary System Flashcards
Topmost layer of skin
Epidermis
What kind of tissue makes the epidermis?
Epithelial tissue.
Epithelial tissues are avascular.
It is a protective layer
Basement membrane
Barrier between epidermis and dermis.
Dermis
Underneath epidermis
Holds blood vessels because epidermis is epithelial and avascular
Holds hair follicles.
Hypodermis
Below the dermis
Region underneath the skin that provides cushioning, thermoregulation and some storage for adipose tissue. Adipose tissue provides cushioning.
Parts of cutaneous membrane
Epidermis and dermis
Cutaneous membrane=skin
Parts of dermis
- Superficial 20% called papillary dermis. Made of mostly loose areolar connective tissue.holds things that help protect if dermis is breached.
-mast cells: initiate inflammatory response. Helps bring WBCs. Release histamine release heparin. Help mediate inflammation response.
-Macrophages
-fibroblasts:help lay down collagen, elastic fibers, new reticular fibers. Help hold damaged area together. - Bottom 80% of dermis:
Very strong. Made of mostly dense irregular connective tissue. Fibers overlap in multiple directions. Called reticular dermis .
Creates tension lines (tension lines are general direction that collagen fibers go) if cut is parallel to tension lines, then the wound will close up reapproximate. If you cut perpendicular to tension lines, the wound gapes.
Surgeons try to cut parallel to tension lines.
Top of dermis has
Dermal papillae: holds sensory nerve endings. Has loose areolar connective tissue
Epidermal derivatives
-hair follicles
-sebaceous glands
-sweat glands
-nails
When dermis and epidermis is damaged
The progenitor stem cells can divide and regrow epidermis
Third degree burn
Below follicles. Burns all the way through dermis below follicles. No more progenitor stem cells left. Situation where you could need a skin graft
Arrector pili muscles
Involuntary muscle, cause goosebumps, causes hair to stand on end
Activated by sympathetic nervous system.
Might help pump sebum onto skin
Sebaceous glands
Attached to hair follicles,
Holocrine glands. (Glandular cells inside are constantly dividing) Glandular cells inside form sebum
Sebum
Lipid protein rich substance. Keeps epidermis and hair healthy.
Sensory nerve endings
Feel temperature and pain
Hair follicle plexus
Innervated structure that connects to hair follicle.
When you pull hair out, it hurts.
Assists skin with perception of touch. When hair glides across a surface, you feel that as perception of touch.
Tactile sensors
Receptors for light touch. In papillary dermis.
Meissner’s corpuscules
Receptors for light touch
Small specialized sensory receptors.
Let you sense textural differences.
Sit in dermal papillae
Lamellar or pacinian corpuscules
Sense deep vibration in skin and various organs like pancreas and urinary bladder.
Ruffini corpuscule
Senses skin stretching movement and finger position.
Merkel cells
In epidermis, modified epidermal cells. Receive touch info.
Eccrine glands
Merocrine glands
Merely secrete.
None of the cell breaks down and becomes part of the secretion. Mostly water. Active during sweating. Water, electrolytes, vitamin c and bit of nitrogenous waste. Important in homeostasis of body temperature.
What mechanism controls body temperature
Negative feedback loop.
Hypothalamus senses that you’re too warm, sweat glands are activated. Sweat evaporates from skin releasing heat.
What kind of blood vessels are in dermal papillae
Fine capillaries
Larger blood vessels in
Dermis
Largest blood vessels in
Hypodermis beneath the skin.
Subcutaneous layer aka
Hypodermis of skin
Apocrine sweat gland
A little bit of cell breaks down during secretion. Become active in axillary and groin areas. Gives BO
Modified apocrine sweat glands
Ex: cerumenous glands in external acoustic meatus.
Also mammary glands
Stratified squamous epithelium
On surface of epidermis, keratinized. Lose about 50,000 skin cells per minute.
Cells at base are
Mitotically active. Just above basement membrane.
Keratinocytes
Keratinized cells
Keratin
Highly abundant structural protein in body. Protective. Prevents water from leaving through skin. Think of it like armor.
As you go up on epidermis
Build up of keratin, see if we need addition of melanin to help protect nuclei of rapidly dividing cells from uv radiation.
In outermost layer: dead cells filled with keratin.
Where to find non keratinized stratified squamous epithelium
Vagina, esophagus,
Layers of epidermis
Corneum
Lucidum
Granulosum
Spinosum
Basale (has melanocytes and mitotically active keratinocytes)
What is under basement membrane
Loose areolar connective tissue
Blood vessels capillaries
Mast cells
Macrophages
Fibroblasts
Stratum basale
Mitotically active
Lots of cells division in conjunction with cytokinesis
Mitosis+cytokinesis= cell division
Melanocytes (octopus-like nature: deliver melanosomes filled with melanin to recently divided cells..help protect recently divided cells from uv radiation)
-merkel cells
Melanin concentrates where?
On top of nucleus
In response to UV radiation. Protects DNA from mutation. Think like umbrella.
Squamous cells carcinoma
Cancer in flatter cells
Basal cell carcinoma
Cancer in a basal cells
Least likely to metastisize
Melanoma
Mutations occuring in DNA of a melanocyte. Has the ability to produce cytoplasmic extensions.
Melanomas are only 5-10 of all skin cancers. Represent 85-90% of all skin cancer deaths. Keep eye on
Stratum spinosum
Has pointy ends
Artifact of early histology
Stratum granulosum
Granules are vesicles that have keratin
Stratum corneum
Dead keratinized cells
Dead cells sloughing off
Stratum lucidum
Only on palms and soles of feet. Only in really thick skin
What makes epidermis waterproof
Glycoprotein between cells.
Lots of protein with sugary content.
Get sticky when comes into contact with water.
Desmosomes(anchoring junctions) prevent epidermis from shearing.
Epidermal layer
Relatively thin. Can sometimes get diagnostic info from skin color
Yellowish skin+ yellowish eyes
Jaundice, liver issue
Overheated
Reddish pinkish skin.
Caused by dilation of blood vessels in papillary dermis. Try to turn skin into radiator to dissipate heat
Pale grey blue skin
Cold
Superficial blood vessels in skin already cold, possibly closer to hypothermia.
Constricted blood vessels trying to keep body heat deep around organs, causing them to look pale.
Where do cells look more cuboidal/columnar?
Stratum basale
Pneumonic for layers of skin
Californians
Like
Girls
String
Bikinis
Papillary dermis
Made of loose areolar connective tissue
Reticular dermis
Looks like marbled meat
Collagen fibers go in all different directions
Everyone has same number of
Melanocytes. Only type and amount of melanin that varies producing different skin tones.
Trade off s in both directions
Eumelanin
Brown, black type
Pheomelanin
Orange type of melanin
Someone with darker skin has
Delivery of Lots of melanosomes into keratinocytes in stratum spinosum. Continuing up
What happened in lighter skin
Less melanin is deposited from those melanosomes
Darker skin
More resistant to UV radiation. Less likely to get cancer. Need more sunlight for vitamin D needs
If you’re fair skinned
Need less sunlight to meet vitamin D needs
Mole
Benign growth of melanocytes. Typically benign
Vitiligo
Can happen to anyone.
Patches of no pigmentation.
Is autoimmune disorder where immune system incorrectly attacks melanocytes.
80% of all autoimmune cases are in women
Hair bulb
Hair bulge
Bulge: hold progenitor stem cells around where arrector pilli muscle attaches.
Hair bulb: holds hair
Connects basement membrane of the epidermis to hair follicle
Arrector pili muscle
Helps move sebum, causes goosebumps
Hair papilla
Have capillary bed there
Hair is made of keratin. Rapidly dividing keratinocytes
Hair follicles originate from
Epidermis
Sebaceous glands attached to
hair follicle
Holocrine gland
Produces sebum
Cradle cap
Overactive sebaceous glands cause scaly, dried sebum ball all over the head
Base of hair follicles is often in
Subcutaneous layer. Can tell it’s subcutaneous because of adipocytes
Hair shaft
Emerges of skin
Dense irregular connective tissue
Makes reticular dermis. Reason why dermis is so strong
Alopecia androgenetica
Male pattern baldness
Alopecia areata
Autoimmune disorder
Attacks hair follicles
Patches without hair.
Antigen presenting cell
Macrophage
Takes bits of digested substances outside.
When t lymphocytes has matching antigen, tells t lymphocytes to start immune response
Also called dendritic cells when they have long cytoplasmic extensions
Dendro-
Branching
Dendritic cells
In epidermis can patrol for pathogens
Skin is a bit acidic
Helps fight off pathogenic activity
Soaps are alkaline
Can sometimes disrupt skin ph barrier when very excessive
Hair bulge
In middle of hair follicle
Exocrine glands
All over body
Secrete substances to surface of skin
Secrete to a surface
Pancreas has exocrine glands
Types of exocrine glands
1.Merocrine gland:
-none of cell cytoplasm breaks down to form secretion goes out through duct
(Eccrine sweat gland)
2.Apocrine glands: small fragments of cell breaks off and becomes part of secretion.(Axillary and groin BO, cerumenous and mammary)
3.Holocrine glands: entire cell breaks down and becomes part of the secretion. (Sebaceous glands) Double stacked cells because cells are destroyed
Root hair plexus
Can determine if follicle is moving. Help it contribute to sense of touch
Free nerve endings
Sense pain
Meissner’s corpuscules
Found in dermal papillae
Light touch
Pacinian corpuscules
Detect deep vibration in lower end of dermis and in some organs of body
Ruffini endings
Heat
Merkel discs
Plugged into epidermis with sensory neurons connected to them
Pressure receptors
Thermoregulation
Capillaries of dermal papillae constrict to keep organs warm. Blood circulation avoids surface to retain heat
Capillaries dilate when hot, more blood circulates uses surface of skin like radiator to cool off. Causes surface of skin to heat up, blood circulates to surface of skin to dispel heat.
Shivering
If too cold, cause shivering, skeletal muscles involuntarily contract. Leads to additional waste heat production from ATP working so hard
Aging of skin
Lose adipose tissue in subcutaneous layer.
Develop age spots (lipofuscin granules).
Skin irregularities more common over time. Hair might grey. Melanocytes aren’t producing melanin
Actinic keratosis
Mass of keratinized cells running down to stratum basale. Abnormal. Not cancerous but could turn into cancer. Think as precancerous benign situation
Squamous cell carcinoma
Breaks through basal layer of epidermis
Doesn’t have basement membrane cap.
Least likely to break through stratum basale and get into dermis
Basal cell carcinoma
Rarely escape because they have built in ability to make fibers and proteins tend to seal themselves off
Why is it bad for epidermal cells to get into dermis
Cancer cell lines lose their stickiness, lose positional information. Grow out of control and can break off and enter blood stream . Usually an outpatient thing to get removed
Melanoma
Already have ability to produce cytoplasmic extensions. Quick to invade to other tissues.
Neoplasm
New growth
ABCDE
Asymmetrical
Border(irregular border)
Color( 2 or more colors)
Diameter (is diameter greater than pencil eraser head)
Evolution (is it rapidly changing?) or elevation (is it growing upward?)
Decubitus ulcer
Pressure sores
Skin breakdown
In bony processes.
If person isn’t rotated and moved can get skin breakdown.
Stage 1
Skin is unbroken but inflamed red
Stage 2 decubitus ulcer
Skin is broken down to epidermis or dermis
Stage 3
Ulcer extends to subcutaneous fat layer. Gets down pretty deep. Infections can spread easily.
Stage 4
Spreads down to muscle or bone
Acne
Sebaceous glands are very active to androgens
Caused by burst of sex hormones. Caused by plugged follicles. Sebaceous glands pump out sebum. If bacteria gets trapped in sealed off plugged follicle, it can divide rapidly. Uses sebum as food source. Can get infected.
Whitehead
Sebum is sealed off from air
Blackhead
Air gets inside and you get oxidation. Turns color a bit darker.
First degree burn
Only surface of epidermis
Heals back normally
Second degree burn
Deeper injury causes blistering
Damage into dermis
Blisters caused by inflammation. Capillaries swell and plasma centers area around capillary beds. Helps push cellular debris and bacteria into lymphatic system so it can get screened out and you can defend yourself from potential infections
Can recover from damage
Has hair follicles left, can grow back epidermal layer
Third degree burn
Involves all layers of skin
No hair follicles left. Requires skin grafting
Fourth degree burn
Burns extend into the muscle and bone
So many nerves are destroyed, it may not be as painful as second degree burn
Harder to treat, make sure not infected or dehydrated,
Autograph
Skin graft from self to cover up and replace
Rule of nines
Judge what percentage of body was burned and what portion of body is left for grafting
