Wk 5 Integumentary System Flashcards
Skin is called?
Cutaneous
Largest organ
Cutaneous has 2 main regions
°Epidermis
°Dermis
Epidermis is made from what type of tissue?
Keratinized stratified Squamous Epithelial (waterproof & protection)
Dermis is made from what type of tissue?
Loose CT & dense irregular CT
Skin structure
(6 things)
° accessory structures
° sensory receptors
° arrector pili muscle
° epidermis
° dermis
° hypodermis
Skin structure
Accessory structures:
° sweat glands
° sebaceous glands
° hairs
° nails
Skin structure
Sensory receptors:
detects heat, cold, pain, and pressure
Skin structure
Arrector pili muscle:
Small bands of SMC (smooth muscles) associate with hair
Skin structure
Epidermis:
°avascular (no blood flow)
° transport of O2 and nutrients by diffusion
Skin structure
Dermis:
° vascular (has blood vessels)
Skin structure
Hypodermis:
° superficial fascia/ subcutaneous fat is deep in the dermis
°not part of skin, anchors skin to deeper structures
° loose CT and adipose
° vascular (blood vessels)
Integumentary system
function:
(5 functions)
° Protect
° sensation
° thermoregulation
° excretion
° synthesis
Integumentary system
function: protection
°Mechanical trama
° pathogens
° environment
Integumentary system
function: sensation
Preceive changes in the body’s internal / external environment
Integumentary system
function: thermoregulation
Uses negative feedback loops to maintain stable internal temperature
(Muscles and metabolism)
Integumentary system
function: excretion
Process where waste products and toxins are eliminated (sweat)
Integumentary system
function: synthesis
Making Vitmin D and calcitriol by using UV rays (sunlight)
Body temperature above normal:
Stimulus
Body too hot due to weather or sickness
Body temperature above normal:
Receptors
Thermoreceptors detect an increase in body temperature
Body temperature above normal:
Control center
Thermoregulatory center in the brain (hypothalamus) acts as a thermostat
Body temperature above normal:
Effector / response
The control center stimulates sweating and vasodilation (VD) of vessels in dermis
Body temperature above normal:
Homeostasis and negative feedback
° body temperature returns to normal
° thermoregulatory center decreases output to glands and vessels
Body temperature below normal:
Stimulus
Body temperature drops below normal range, too cold
Body temperature below normal:
Receptors
Thermoreceptors detect the drop in temperature and relya the info to the hypothalamus
Body temperature below normal:
Control center
Thermoregulatory center in the brain (hypothalamus) acts as a thermostat
Body temperature below normal:
Effector / response
Blood vessels in dermis vasoconstrict, decrease sweating, increase shivering
Body temperature below normal:
Homeostasis and negative feedback
° body temperature returns to normal
° thermoregulatory center decreases output to vessels and muscles (reduce shivering)
Lose heat:
Sweating and vasodilation
Conserve heat:
Decrease sweating and vasconstrict
Produce heat:
Muscle contraction
Calcitriol
Necessary for absorption of Ca++ by sunlight
Ca++
Necessary for nerve function, muscle contraction, bone
Epidermis
° most superficial layer (surface)
° composed of mostly keratinocytes
° produces keratin (protein)
Epidermis layers:
(There are 5)
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
Epidermis:
Stratum corneum
° Outer most layer
° Mostly dead cells
° made of several layers
Epidermis:
Stratum Lucidum
° thick skin only (palms and soles of feet)
° clear layer (dead keratinocytes)
Epidermis:
Stratum Granulosum
° 3 to 5 layers of cells
° keratin filled cells (water resistance)
Epidermis:
Stratum spinosum
° bit of mitosis
° metabolically active and mitotically active
Epidermis:
Stratum basale
° (stratum germinativum)
° Deepest layer.
° most mitosis
° most metabolically active and mitotically active
Keratinocytes life cycle
° Made by mitosis in the stratum basale layer
° Get pushed up to the stratum corneum as they age and die
° Mitosis happens mostly at night.
Other Cells of the epidermis (3 of them)
° Dendritic (langerhans) cells
° Merkel cells
° melanocytes
Dendritic (langerhans) cells
° Located in stratum spinosum
° Phagocytes of the immune system
° Protect skin and deeper tissues from pathogens.
Merkel cells
° Located in stratum basale
° Sensory receptors detect light touch.
° Fingertips, lips, and at base of hair.
Melanocytes
° Located in stratum basale
° produce melanin (skin pigmentation) (protein)
Thick skin
° All 5 epidermis layers
° Thick stratum corneum
° No hair follicles, many sweat glands
Thin skin.
° Has only 4 layers of epidermis (no stratum lucidum)
° Many hairs, sweat glands, and sebaceous glands.
Callus
Additional layers of stratum corneum form and either thick or thin skin due to repetitive pressure.
Dermis tissue type?
Dense irregular connective tissue.
Highly vascular layer deep to epidermis.
Dermis function:
° Provides.
° Contains
° Anchors epidermis in place.
Dermis made of 2 layer:
° Reticular layer
° Papillary layer
Papillary layer
° Composed of loose connective tissue.
Dermal papillae
° Tiny projections.
° Capillary loops.
° Tactile (Meissner) corpuscles ( Light touch)
Reticular layer
° Deepest thickest layer of the dermis.
° Mostly dense irregular ( collagen and elastic fibers)
° Rich in proteoglycans ( keep skin firm and hydrated)
° Lamellated (pacinian) corpuscles ( pressure and vibration associated with skin)
° Found in the Reticular layer are blood vessels, sweat glands, hair, sebaceous glands, and adipose tissue.
Skin wrinkles.
Due to age-related decreased collagen and elastic fibers, proteoglycans and adipose tissue in the dermis.
Skin wrinkles reduces…
Skin firmness, hydration and recoil ability after stretching.
Skin wrinkles’ appearance can be minimized by:
Botox, fillers, and tropical creams.
Melanin
° Skip color.
° Protein.
° Melanocytes
° Protect keratinocytes DNA from mutations induced by UV rays.
° number of melanocytes is virtually identical among individuals.
° Spectrum of skin tones due to differences in amount of melanin produce.
Carotene
° Ingest yellow orange vegetables.
° Imparts yellowish color to stratum corneum.
Hemoglobin (RBC)
Coloration depends on blood flow to dermis
Erythema
Increase blood flow.
Pallor
Decrease blood flow.
Cyanosis
Low oxygenated blood.
Common variations of pigmentation.
°Freckles
°Moles
°albinism
Freckles
Small area of increased pigmentation. (Melanin production)
Moles or nevus
Area of increased pigmentation due to prolifreation or melanocytes ( not increased Melanin production)
Albinism
Melanocytes fail to manufacture tyrosinase ( enzyme), resulting in a lack of pigmentation
Hair
Known as Pili
Protrude from surface of skin over entire body except thick skin, lips, and parts of external genitalia
Hair(pili)
Cuticle
Outer
Hair(pili)
Cortex
Middle
Hair(pili)
Medulla
Inner
Hair(pili) function
° Protect by preventing substances & organisms entering eyes & nose
° Protect underlying skin of scalp from uv radiation & physical trauma
° Sensory neuron detects change in environment
Hair(pili)
What is it made out of?
Keratinized stratified Squamous Epithelial Tissue
Hair(pili)
Structure
Shaft
Root
Matrix
Regions
Arrector pili muscle
Hair(pili) structure
Shaft
° anything above the skin
° projects from the skin surface
° dead keratinized cells
Hair(pili) structure
Root
° anything below the skin embedded in hair follicle
°embedded in the dermis
° surrounded by sensory neuron
° hair papilla
° hair bulb
°many epithelial cells are alive
Hair(pili) structure Root:
Hair papilla
Projection of blood vessels in indented base
Hair(pili) structure Root:
Hair bulb
Root + hair papilla
Hair(pili) structure
Matrix
Small # of actively diving keratinocytes found at base of root
The 3 regions of hair
° inner medulla
°middle cortex
°outermost cuticle
Region of hair:
Inner medulla
Soft keratin
Region of hair:
Middle cortex
Hard keratin provides strength
Region of hair:
Outermost cuticle
Single layer of over lapping keratinocytes containing hair keratin; provides physical strength
Hair structure:
Arrector pili muscle
Small bands of smooth muscle associated with hair
Goosebumps
(Piloerection)
Hair stands up
Hair growth
Around 1-1.5 cm per month
Hair pigmentation and texture
Hair color determined by melanin
Hair pigmentation and texture:
Blond hair
Has alittle melanin
Hair pigmentation and texture:
Black hair
Contains alot of melanin
Hair pigmentation and texture:
Red hair
Has special reddish pigment containing iron
Hair pigmentation and texture:
Gray or white
Melanocytes produce
Nails
Composed of stratified Squamous Epithelial Tissue filled with hard keratin
Nails parts
° nail plate
° lunula
° eponychium
° hyponychium
Nail plate
Sits on top of nail bed
Lunula
Half moon shaped region of proximal nail plate
Eponychium
Cuticle
Hyponychium
Stratum corneum under free edge of nail
Sweat gland
° sudoriferous
° merocrine secretion
Sweat Gland (Sudoriferous)
eccrine
Widespread, mostly water, waste, electrolytes (everywhere on body)
Sweat Gland (Sudoriferous)
apocrine
Axillary & anal regions, function at puberty
Sweat Gland (Sudoriferous)
Modified: ceruminous
Produces earwax (cerumin) ear canal
Sweat Gland (Sudoriferous)
Modified: mammary
Produces milk (breast)
Sebaceous glands
° Holocrine
° produces sebum (oily)
° think skin only
° hydrophobic barrier
Cancer
Common disease in the world is caused by mutated DNA that loses control of cell cycle
Tumor
Formation of large population of cells
Metastasize
Tumor spreads through blood or lymphatic vessels to other tissues and continues to divide
3 cancers that affect skin
° Basal cell carcinoma
° Squamous cell carcinoma
° malignant melanoma
Basal cell carcinoma
Most common
Arises from keratinocytes in stratum basale (easily treatable)
Squamous cell carcinoma
2nd common
Arise from keratinocytes of stratum spinosum (easily treatable)
Malignant melanoma
Cancer from melanocytes
(Hard to treat can spread)
