ch 5 (copy)

Integumentary System,Skin, hair, nails, & cutaneous glands

Skin,- body's largest organ - 2 layers: 1. epidermis: epithelium of skin 2. dermis: connective tissue of skin

Hypodermis,*not a part of integumentary system - connective tissue just underneath skin Thick Skin vs Thin Skin,

Thin: - covers most of body - hairy, has both sebaceous oil glands & sweat glands - no stratum lucidum

Thick: - palms of hands, front of fingers, soles of feet, bottom of toes - hairless, no sebaceous oil glands, has sweat glands - adaptive for high friction

Skin functions,- resistance to trauma & infection - water retention - synthesis of vitamin D - sensation - thermoregulation - nonverbal communication

Structure of Skin & Hypodermis Tissue, Epidermis - Features,1. keratinized stratified squamous epithelium - Superficial cells are not alive 2. Avascular - nutrients like oxygen move from deeper connective tissue (dermis/hypodermis) via diffusion 3. Sparse nerve endings - most receptors for sensation located in the dermis Avascular,no blood supply

Keratinocytes (epidermis cell),- synthesize the fibrous protein (keratin) - the majority of epidermal cells (in many layers)

Stem cells (epidermis cell),- divide & produce keratinocytes - only in stratum basale Melanocytes (epidermis cell),- make melanin: a brown/black pigment melanin is taken up by keratinocytes & used to protect DNA from UV radiation

Tactile (Merkel) cells - epidermis,touch receptors that join with nerves Dendritic (Langerhans) cells - epidermis,immune surveillance layers of epidermis,Memory Trigger: Come Let's Get Sun Burnt

Stratum basale,*deepest layer** - one cell thick & touches basement membrane - varied cell types present - also called stratum germinativum for its role in the formation of new cells - mostly keratinocyte stem cells (if layer is destroyed, can't regenerate new skin)

Stratum spinosum,- aka. "prickle cells" - several layers of cell - often the thickest layer of epidermis - keratinocytes begin to actively synthesize keratin which builds up in the cells giving them a "prickly" appearance

Stratum granulosum,as cells move through this layer, keratin is replacing their organelles - causing cell apoptosis (death)

Stratum lucidum,**only in thick skin** - few layers of dead, flattened, translucent keratinocytes

Stratum cornenum,**most superficial layer of the epidermis** - lamellar granules in this layer make it water-repellant - these dead cells are shed constantly & being replaced through process of cell apoptosis

The Dermis,- rich in collagen fibers - large blood supply - papillary layer (superficial) & reticular layer (deeper) - contains: cutaneous glands, hair follicles, arrestor pili, and nail roots

Papillary layer (dermis),- superficial, thin layer - Areolar connective tissue* - rich in blood vessels Reticular layer (dermis),- deep, thick layer - dense, irregular connective tissue* - striae (stretch marks): stretching of the dermal collagen

Hypodermis,*not a layer of the skin* - located below dermis - contains adipose (subcutaneous fat) & areolar connective tissue

Hypodermis functions,1. Energy storage 2. Thermal insulation 3. Connection to deeper tissue

Melanin,produced by melanocytes -

Eumelanin: brownish black

pheomelanin: reddish yellow - skin tones vary due to different types & distributions of melanin

Hemoglobin,red pigment of blood

Carotene,- yellow orange - concentrates in stratum corneum

Cyanosis,- blueness - lack of oxygen

Erythema,- redness - increased blood flow

Pallor,- pale or ashen - reduced blood flow Memory Trigger: Pale is in the name.

What is the difference when the skin lacks Oxygen or lacks blood flow?,Lack of O2 is Cyanosis. Reduce blood flow is Pallor.

Albinism,- white (no pigment) - genetic lack of melanin Memory Trigger: Albino Tigers are more White

Jaundice,- yellow - liver & excess bilirubin deposits in skin (This is when alcoholics have liver failure, they turn yellow)

Hematoma,bruise/multiple colors

Friction ridges of fingertip,*skin marking* - aid in sensitivity to texture & ability to grasp - cause fingerprint pattern

Flexion line (creases),*skin marking* - where skin near joint attaches to deeper tissue

Freckles,*skin marking* - flat, melanized patches - vary w/ heredity & UV exposure

Mole (nevus),*skin marking* - elevated patch of melanized skin

Hair,- aka. pilus (singular) or pili (plural) - an accessory organ of the skin (like nails & skin glands) - a filament of keratinized cells - grows from hair follicle

Downy hair (lanugo),fine, downy, unpigmented hair of the fetus

Vellus hair,- fine, unpigmented - 2/3 hair of women - 1/10 hair of men - all hair of children (except eyebrows, eyelashes, & scalp) (Also the hair for peaches :)

Terminal hair,- coarse, pigmented - eyebrows, eyelashes, scalp - after puberty 1. axillary (armpit) 2. pubic 3. male facial hair 4. some hair on trunk & limbs Memory Trigger: Terminal = term, Kids reach a term in life where they grow more hair (Puberty)

Structure of the Hair & Follicle,3 zones along length of hair: bulbs, root, shaft

Bulb,- swelling at base where hair originates in dermis -

dermal papilla: provides nutrition - hair matrix: hair's growth center (mitosis)

Root,- remainder of hair within follicle - dead tissue

Hair shaft,- portion above the skin's surface - dead tissue 3 concentric layers of hair,1. medulla 2. cortex 3. cuticle

List the 3 concentric layers from superficial to deep.,1. Cuticle 2. Cortex 3. Medulla (Medulla like the medullary canal is in the bone, so medulla is inside of the concentric layers) (Cuticle is the most superficial layer, like the nail is on the outside)

Medulla (hair),- internal layer - loosely arranged cells & air spaces

Cortex (hair),- bulk of hair - several layers of long cells

Cuticle (hair),- outer layer - overlapping scaly cells

Hair follicle,- diagonal tube extending in dermis, or even hypodermis - 2 layers: 1. epithelial root sheath (inner layer) 2. connective tissue root sheath (derived from dermis) - hair receptors - arrector muscle (arrector pili) Hair receptors,nerve fibers that respond to a hair's movement looks like tree roots Arrector muscle (arrector pili),smooth muscle that raises hair on end & causes "goose bumps" Nail plate consists of:,Free edge Nail body Nail root Nail fold consists of:,Nail groove Nail bed consists of:,Hyponychium (secures nail to nail bed) Nail matrix Lunule Eponychium (cuticle) Nails,- derivative of stratum corneum - composed of thin, dead, scaly cells with parallel rows of keratin - primates have flat nails for easier manipulation Difference between hyponychium and eponychium,*

hyponychium: secures nail-to-nail bed - under the free edge *

*eponychium: cuticle - the thing nail salons cut off near the lunule Cutaneous glands,

What are the Sweat (Sudoriferous) Glands?,Eccrine and Apocrine - Eccrine is cooling sweat - Apocrine is the stinky stuff on hair

Eccrine (merocrine) glands,- numerous, widespread (esp. abundant on palms, soles, & forehead) - simple ducts lead to pores at skin surface of epidermis - produce watery, salty perspiration to cool body (Soccer activated my eccrine glands, which produces cooling sweat)

Apocrine glands,- found in groin, anal region, axilla, areola, and beard - ducts open into hair follicles - produce sweat with many fat molecules bacterial metabolism of fat causes odor Memory Trigger: Apocrine sounds like an ape. Apes are smelly and hairy.

Sebaceous glands,- produce oily secretion aka. sebum - usually open into hair follicle - keep skin & hair from becoming dry/brittle Memory Trigger: SEBaceous sounds like sebum. Oil on my face makes look like a bum.

Ceruminous glands,found in the auditory canal - secrete cerumen (earwax) -> combination of sebum & dead skin cells -> keeps eardrum pliable, waterproofs canal, kills bacteria, and coats guard hairs Memory Trigger: CERUMinous sounds like cerumen.

Mammary glands,- produce human milk in the breast tissue of females - glands develop during pregnancy & lactation (otherwise small & disfunctiontal) -> breasts exists in male but do not function - are modified apocrine glands

Skin cancer,- induced by UV rays (natural & tanning beds) - most common in : elderly, fair-skinned, immunosupressed 3 types of skin cancer. Rank least to worst.,1. basal cell carcinoma 2. squamous cell carcinoma 3. malignant melanoma

Which is more dangerous: basal cell carcinoma or squamous cell carcinoma?,Basal cell carcinoma is the least dangerous of the 4 types of skin cancer.

basal cell carcinoma,- most common; least dangerous - hardly metastasizes (spread) - arises in stratum basale & invades dermis

squamous cell carcinoma,- arises from keratinocytes of stratum spinosum - can metastasize to lymph nodes - about 20% mortality (death rate)

melanoma,- most deadly, but only 5% are malignant melanoma - arises from melanocytes of an existing mole - metastasizes (spread) quickly (reason why it's most lethal)

Burns,- leading cause of accidental death - death primarily from: 1. fluid loss 2. infection 3. toxic effects of eschar (dead tissue)

first-degreee burn (partial-thickness burn),only epidermis* - usually localized - redness, slight edema, & pain - sunburn

second-degree burn (partial-thickness burn),*epidermis & part of dermis* - red, tan, or white - blistered & painful - may damage hair follicles, nerve endings, & cutaneous glands - severe sunburns & scalds t

hird-degree burn (full-thickness burn),*epidermis & dermis are completely destroyed* - causes contracture (abnormal fibrosis) & figurement ~ may not feel pain due to burned off nerve endings (also for 4th degree burn)

In terms of glands, how are thin and thick skin different?,Thin has everythang. Sebaceous oil glands and sweat glands.

Thick skin has no sebaceous oil glands, but has sweat glands.

What layer are keratinocytes only located in?,Only in the stratum basale

What is the thickest layer of the epidermis?,The Stratum Spinosum Memory Trigger: You have to be thick skinned like dinosour spikes

Which layer of Epidermis does apoptosis occur in?,Stratum granulosum

What layer is only in thick skin?,Stratum Lucidum

Which Epidermis layer is water repellent and sheds constantly?,Stratum corneum

How many layers are there in thin skin? Thick Skin?,4 layers in thin skin,

5 layers in thick skin Memory Trigger: Thick skin : Come, Let's Get Sun Burned Thin skin : Careful, Getting Sun Burned Which skin layer contains collagen?,Dermis Why doesn't the epidermis have a large blood supply compared to the dermis?,It is the most superficial. You don't feel much in this layer and it is composed of dead stuff. Striae,Stretching of the dermal collagen

What dermis layer does dense, irregular connective tissue classify under?,Reticular

What layer does areolar connective tissue classify under?,Papillary Layer

Adipose tissue can be found in what part of the skin?,

Adipose is found in subcutaneous fat,

which is in the hypodermis layer. (The hypodermis layer also contains the areolar connective tissue)

Eumelanin,Brownish Black

Pheomelanin,Reddish yellow Memory Trigger: Phineas has red hair and yellow shirt (red and yellow make orange = phineas shirt)