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Lecture 3
Integumentary System - The Skin & its Appendages
28
Anatomy
Undergraduate 3
09/27/2010

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Cards

Term
what does the integumentary system consist of?
Definition

  • the skin, which is the largest organ of the body; also the larges emunctary (or organ of elimination)
  • its appendages: sweat glands, sebaceous oil glands, hair and nails

Term
integumentary system characteristics
Definition

 

  • waterproof, stretchable, washable, automatically repairs small rips and burns, and is garuneteed to last a lifetime with reasonable care
  • covers the entire body, and is about 7% of the total body weight
  • very complex: (1) more than 500,000 cells (2) varies in thickness - thickest at the palms of the hands and soles of the feet

 

Term
what are the 2 distinct layers of the integumentary system?
Definition
epidermis & dermis
Term
epidermis
Definition
  • superficial layer of thick epithelium (keratinized, stratified, squamous cells)
  • the deep epidermis undergoes contiuous mitosis, pushing cells by the tume they reach the surface, they are dead and filled with keratin
  • brand new skin every 35-45 days; the production balances the loss at the surface of the skin
Term
dermis
Definition
  • deep to epidermis
  • fibrous CT layer that is strong and flexible
  • made up of collagen, elastin and reticular fibers
  • contains a high amount of nerve fibers and blood vessels; can hold up to 5% of blood volume of the body
  • heightens when there is a need for cooling the body
  • lessens when blood is needed elsewhere
Term
hypodermis
Definition
  • the fatty or adipose layer deep to the dermis that shares some of the skin's functions
  • this layer is also known as subcutaneous tissue or superficial fascia
  • functions to isolate the body from cold, softens any impact, and acts as the body's main energy reserve
  • NOT PART OF THE INTEGUMENTARY SYSTEM
Term
sensory receptors found in the skin
Definition
a multitude of sensory receptors are distributed over the entire surface if the skin, although different parts of the body have varying concentrations. they respond to various stimuli and send the relevant information to the nervous sytem to be suitbly interpreted
Term
meissner's corpuscle
Definition

touch receptor

 

part of the dermis

Term
vater-pacini
Definition

receptor for pressure and vibration

 

part of the dermis

Term
ruffini's corpuscle
Definition

heat receptor

 

part of the dermis

Term

krause's corpuscle

 

Definition

receptor for cold

 

part of the epidermis

Term
free nerve ending
Definition

receptor for pain

 

part of epidermis

Term
merkels disks
Definition
light touch superficial pressure
Term
hair follicle receptor
Definition
light touch
Term
functions of the skin
Definition
  • cushions and insulates the deeper body organs, and protects the body from mechanical damage
  • protection from harmful chemicals, thermal damage and invading bacteria
  • waterproof epidermis, preventing unnecessary loss of water across the body surface
Term
skin regulates heat loss through rich capillary networks and sweat glands (______)
Definition
controls body temp
Term
  • the skin acts as a ______ system with the loss of urea, salts, and water through sweating
  • the skin screens harmful UV rays and its epidermal cells; uses these rays also to sinthesize (Vitamin D) -> hormonal control, creation in enzymes helps lower _______
  • contains sense orgns callded sensory receptors that are associated with afferent sensory nerves (they sense _____, _____, _____ and _____
Definition
  • mini-excretory
  • inflamation
  • they sense touch, pressure, temp and pain
Term
injuries and adaptaions
Definition
where skin experiences friction, both cell production and keratin formation are heightened
Term
callus
Definition
thickening in response to persistent friction (adaptive response)
Term
blister
Definition
short-term severe friction that causes separation of the epidermis from the dermis by a fluid-filled pocket
Term
stretch marks
Definition
caused by extreme stretching of the skin, tearing the dermaal layer; produces scars in the dermis that are not elastic
Term
4 skin appendages
Definition
  1. hair and hair follicles (epidermal)
  2. sebaceous glands and follicles (dermal)
  3. sweat glands (dermal)
  4. nails (epidermal)
Term
hair and nale follicles
Definition
  • located in the epidermal layer
  • hair is 3 concentric layers of keratinized cells
  • follicles are tubular invaginations of epidermis from which the hair grows
  • hair color is determined by melanocytes at the base of the follicles
Term

sebaceous glands and follicles

 

Definition
  • found in the dermal layer
  • these are the skin's oil glands (secrete sebum)
  • found everywhere in the body except the palms and soles
  • functions by hormonal stimulation (especially androgens)
  • softens and lubrictes hair and skin
  • helps the slow loss of water across skin
  • has bacteria-killing action
  • when the gland is blocked, acne is produced (whitehead, blackhead, pimple formation)
Term

sweat glands

 

Definition
  • found in the dermal layer
  • everywhere but nipples and part ofthe external genitalia
  • sweating prevents the overheating of the body
  • heat induced sweating gstarts at the forehead and spreads inferiorly
  • emotion induced sweating ("cold sweat") begins on palms, soles and axillae (then spreads to other areas)
  • palms, soles and axillae -> innervated by sympathetic chonlinergic post-synaptic fibers
  • sweat is primarily a filtration of blood, so it is 99%  water with some salts and metabolic wastes
  • sweat is acidic so it is bacteria-static (retards the growth of bacteria on skin)
  • MAIN cooling system & has an anti-bacterial function
Term
nails
Definition
  • found in the epidermal layer
  • modified, hardened version of the epidermis
  • protective mechanism, grasp small delicate objects
  • some examples: clubbing (heavy smoking), spoon nail (nutrient deficiency), and beau's line (lack of iron)

 

Term
diseases of the skin:
Definition
  • psoriasis - inflamatory of the skin (steroid-treatment)
  • auto immune
Term
skin cancer
Definition
  • squamous cell carcinoma: 2nd most common
  • basal cell carcinoma: most common
  • malignant melanoma: very aggressive, rapidly growing (shape, color, diameter evolving)
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