Integumentary System Flashcards
4 types of tissues
- Epithelial
- Connective
- Nervous
- Muscle
What are the two different types of intercellular attachment categories and junctions in each category?
- Communicating junctions (gap)
- Adhering junctions (tight, desmosome, plasmodesmata???)
What are the functions of the integumentary system?
- Protects the body
- Communication (blushing, coloring, warning)
- Vitamin D synthesis
What does the integumentary system protect the body from?
pathogens, abrasions, uv radiation, desiccation
What do gap junctions do?
Allow rapid communication - link cytoplasm of one cell to another with connexin channel proteins (found in heart)
What do tight junctions do?
Limit transportation - proteins fuse plasma membranes together, intercellular space sealed shut - like pants pockets/seam (found in blood-brain barrier and intestinal/bladder cells)
What do desmosomes do?
Relates to the cytoskeleton which keeps structure of the cell - form strong cohesive tissue from falling apart - strongest of all attachments (skin) (gutter rivet)
Define desiccation
drying out
Do fish have a keratinized epidermis? Why or why not?
Fish lack a keratinized epidermis because they live in the water
What are the 2 types of unicellular epithelial glands in fish?
- Club cells - secrete alarm chemicals (a school of fish one is eaten the others hide)
- Goblet/mucus cells - secrete mucin (reacts with water to make mucous)
What are the two types of fish scales?
- dermal bony scales (Actinopterygii)
- placoid scales (Chondrichthyes)
Compare and contrast types of fish scales
Dermal bony: scale does not pierce epidermis - scales are completely covered by tissue - none is exposed to outside environments in Actinopterygii
Placoid scales: scales and teeth form from the dermis - scales pierce epidermis - (sharks and Chondrichthyes
Is the keratinized epidermis the same across species?
No. Fish do not have a keratinized epidermis and the thickness will fluctuate through species (amphibians have thinner)
What 3 parts make up the cytoskeleton?
- microtubules
- actin
- intermediate filaments
What is a hemidesmosome and where is it located?
Located on the basement membrane - it attaches to cytoskeleton of epidermis but connective tissue on basement membrane
What is the benefit of the mucous cuticle?
- hydrodynamics (maneuver through water)
- pathogens (protective keep out bacteria)
- repugnant chemicals
What gives the shark the ability to move without wrinkling and not taut skin?
helical cross-fibering of collagen
What are the two layers of shark skin?
- stratum laxum (little collagen)
- stratum compactum (packed dense compact collagen)
What is the amount of glands and keratinization in amphibians?
- low keratinization to the epidermis
- glandular secretions to keep skin moist
- no dermal scales
How does Eastern newt skin vary?
Aquatic larvae - active mucus glands - no keratinization
Terrestrial juvenile - moderate keratinization (turn red)
Aquatic adult - weak keratinization - active mucus glands
What organisms (fish/amphibians) have unicellular glands and what have multicellular?
fish = unicellular (goblet)
amphibian = multicellular (poison)
What are the 2 layers of amphibian epidermis?
- stratum corneum (thin)
- stratum basale (layer of epidermis that does mitosis)
What is a xeric habitat?
dry habitat
What is ecdysis and what triggers it?
shedding of reptile skin all at once triggered by ecdysone (hormone)
What are the steps of ecdysis:
- stratum basale grows a new epidermis
- lysosomes trigger autolysis - sep old layer from new
- new layer is now exposed
(all triggered by ecdysone)
Rest -> Renewal -> Shed -> Repeat
What is an example of a reptile integumentary gland?
femoral scent glands of lizards (fence lizards)
Layers of bird epidermis:
- stratum corneum (weak)
- transitional layer
- stratum basale
Compare and contrast body/wing of chicken/bird vs. legs
The body of a bird is weakly cornified (any area covered with feathers) vs. the increased cornified epidermal scales on the legs
What are the 2 types of bird glands?
- uropygial gland
- salt glands
Uropygial gland
oil gland right above tail feathers - used in preening - move lipid wax all over feathers which causes water to roll off back
Salt glands
are found in marine birds - excretes excess salt - located by eye
What are the 2 mechanisms of bird coloration?
- pigment with chromatophores
- structural coloration ( light reflectance)
Where are the chromatophores located?
stratum basale & dermis
List the 4 types of pigments of birds and their chromatophores and color:
- carotenoids - erythrophores - red
- carotenoids - xanthophore - yellow
- phaeomelanin - melanophore - brown
- eumelanin - melanophore - black
What causes a flamingo to turn pink?
flamingos are born white, but they receive dietary carotenoids from the food they eat which get embedded in feathers
What are some birds that use structural coloration?
hummingbird, peacock, starling
How is a bird white?
they do not have chromatophores - all light is reflected
What makes birds blue?
There is no blue pigment - it is structural coloration - feathers are actually brown - blue wavelengths are reflected through light
Structural formation of blue feather structure
- keratin cortex
- spongy layer (big air space)
- black melanin layer
Layers of mammal integument skin
- epidermis
- dermis
- hypodermis (subcutaneous level)
What does the hypodermis consist of?
- adipose cells (insulation)
- arteries & veins (run along boundary of dermis)
- sensory nerve fibers
- areolar connective tissue
Areolar connective tissue
“packing tissue” of body - holds material in place
What does transdermal mean and what is an example of this?
across the dermis - nicotine patches (quit smoking)
What are the 2 layers of the mammal dermis and what is the thickness of each?
- papillary layer (thin)
- reticular layer (thick)
What is the total thickness of the average dermis?
1-2 mm thick
What is in the papillary layer?
areolar connective tissue, sensory neurons, capillaries
What is in the reticular layer?
mesh of collagen (gives structure)
elastin (gives flexibility)
What is the role of papillary capillaries?
blushing, cooling off (thermoregulation) - sends blood close to the surface to expel heat
What kind of immune activity is in the dermis?
macrophages destroy pathogens
Where is the attachment of dermis & epidermis?
basement membrane
How many layers is the basement membrane and what are they?
2 - basal lamina (top) & reticular lamina (bottom)
What are the layers of the epidermis?
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum germinativum/basale
What epidermal layer is in mammal thick skin only?
stratum lucidum (most likely not actual layer)
Which epidermal layer in mammals is mitotically active?
stratum germinativum/basale
What are the cells found w/in the mammal epidermis?
- Keratinocytes
- Melanocytes
- Langerhans cells
- Merkel cells
Stratum germinativum
runs up and down papillae (1 cell thick - makes new cells predominately keratinocytes - also melanocytes and Merkel cells
Stratum spinosum
primarily keratinocytes - there are some melanocyte processes and Langerhans cells - it is spiny because stain causes cells to desiccate and shrink
Stratum granulosum
- cells are starting to die
- organelles diseintegrate
- plasma membrane thickens
- cells flatten
- secrete lipids
grainy look comes from keratohyalin granules that link keratin protein fibers by cross-linkage
Stratum corneum
- dead keratinocytes full of keratin fibers
- dry surface unsuitable for many bacteria
- limits transepidermal water loss
- what we see
What are three accessory structures in the integument?
- hair
- sebaceous glands
- sweat glands
What are all the sweat gland types:
- apocrine (2 types: ceruminous & mammary)
- eccrine (aka merocrine)
Sebaceous gland
moisturizes hair with oily secretion of sebum goes to hair shaft
- holocrine secretion
- arrector pili contraction squeezes gland and sebum secreted onto hair & skin
- keeps hair from being brittle
- inhibits bacterial growth
Which type of secretion do apocrine & eccrine glands use?
apocrine & eccrine
Which type of secretion do sebaceous glands use?
holocrine
What two glands are on the hair shaft?
sebaceous & apocrine
Eccrine/Merocrine sweat glnds
cause sweating - highly dense lots on hand sand feet which is beneficial for grip.
- merocrine secretion using myoepithelial cells
- watery secretion released onto skin
What are two examples of myoepithelial contraction in glands?
- mouth when eating something sour (lemon)
- milk letdown
Apocrine sweat glands
- used for communication
- dense on genitalia, belly button, breast, armpits
- merocrine secretion using myoepithelial cells
- viscose, lipid-rich flid
- release onto hair shaft
- onset at puberty
Two examples of apocrine sweat glands
- ceruminous glands
- mammary glands
Ceruminous glands
- only in external auditory canal
- secretions with sebum to form cerumen
Functions of cerumen:
Ear wax
1. antibiotic & antifungal properties
2. traps dirt, dust, debris
Functions of arrector pili muscle:
- communication (goose bumps, hair standing up when scared to look threatening)
- conserve heat when cold ( arrected hairs trap air and body heat warm up)
What is epidermal invagination
the epidermis is pushed way down deep into dermis (hair matrix - as mitosis occurs cells continue to be pushed upwards)
What are the “composite-like” components of a hair?
- cuticle (flattened cells full of keratin - outer)
- cortex - cells with stiff keratin fibers
- medulla - cells with soft, flexible keratin fibers
What are split-ends?
The cuticle wears away and the rods of the medulla frizz out (like a broken frayed wire)
What causes different hair colors?
melanocytes in cortex
What are the different melanocytes and what colors do they form in hair?
- phaeomelanin (red, yellow)
- eumelanin (brown, black)
Compare albinism & melanism:
albinism- highly reduced melanin production
melanism - increased melanin production (black squirrels)
Melanosome transfer contrasts in different skin colors (layers)
- light-skinned (stratum spinosum, stratum basale)
- dark-skinned (stratum granulosum, stratum spinosum, stratum basale)
What is different about dark-skinned melanocytes?
larger and more active not more in quantity
What is the vitamin D-folate hypothesis?
Too little - vitamin d synthesis - rickets
Too much - folic acid destruction - male sterility
What are 4 things that happen to aging skin?
- less active stratum basale (epidermis thins, prone to infections)
- eccrine sweat glands less active (reduced thermoregulation)
- melanocyte activity declines (pale skin, hair turns white/gray)
- reduced subQ fat & blood thinners (facilitate easy bruising)
