Chapter 5: Integumentary System Flashcards
What does the integumentary system consist of?
Skin
Hair
Nails
Sweat glands
Sebaceous glands
The two distinct regions of the integumentary system
Epidermis
Dermis
(Deep to skin) Hypodermis
superficial region that consists of epithelial tissue and is avascular
Epidermis
underlies epidermis. mostly fibrous connective tissue and is avascular
Dermis
not part of the skin but shares some functions
composed of adipose tissue that absorbs shock and insulates
anchors skin to underlying structures
Hypodermis
What does the epidermis mainly consist of?
keratinized stratified squamous epithelium
What are the 4 cell types found in epidermis?
- keratinocytes
- melanocytes
- dendritic (langerhans) cells
- tactile (merkel) cells
- keratinocytes
- melanocytes
- dendritic cells
- tactile cells
4 cell types found in the epidermis
- millions slough off everyday
- tightly connected by desmosomes
- major cells of the epidermis
- produces fibrous keratin (protein)
Keratinocytes
- produces pigment melanin, which is packaged into _____somes
- spider-shaped cells located in the deepest epidermis
Melanocytes
Melanosomes
________ are transferred into keratinocytes, where they protect nucleus from UV damage
Melanosomes
- start shaped macrophages that patrol deep epidermis
- key activators of the immune system
Dendritic (langerhans) cells
- sensory receptors that sense touch
Tactile (merkel) cells
- consists of a single row of stem cells that actively divide
- also known as stratum germination
- 10-25% composed of melanocytes
Stratum basale
- weblike system of intermediate prekeratin filaments attached to desmosomes (makes it appear spiky)
- allows resistant tension and pulling
- melanin granules + dendritic cells are most abundant in this layer
Stratum spinosum (prickly layer)
- 4-6 cell layers thick, cells are flattened
- cell appearance changes
- cells accumulate keratohyaline granules that help form keratin in the upper layer
- calls also accumulate lamellar granules, a water-resistant glycolipid that slows water loss
Stratum Granulosum
- found only in thick skin
- consists of a thin clear band of 2-3 rows of dead keratinocytes
- superficial to stratum granulosum
Stratum Lucidum (clear leayer)
- -20-30 layers of flat, anucleated keratinized dead cells
- accounts for ¾ of epidermal thickness
- dead cells have protective functions
Stratum Corneum (horny layer)
- strong, flexible connective tissue
- cells include fibroblasts, macrophages, and occasionally white blood cells
- fiber in the matrix binds the body hyde
Dermis
contains epidermal hair follicles, oil glands, and sweat glands
Dermis
The 2 layers of dermis
Papillary
Reticular
What kind of tissue is in the papillary layer?
Areolar connective tissue
- areolar connective tissue consisting of collagen fibers, elastic fibers, blood vessels
- loose fibers allow phagocytes to patrol for microorganisms
Papillary Dermis Layer
- consists of course, dense fibrous connective tissue
- collagen fibers provide strength and resiliency
- ECM contains pockets of adipose cells.
Reticular Dermis Layer
What kind of connective tissue is in the reticular dermis layer?
Corse, dense irregular connective tissue
- superficial region of the dermis with fingerlike projections up into the epidermis
- made up of areolar connective tissue
- interlacing collagen and elastic
- contains: capillary loops, free nerve endings, and touch receptors
Dermal Papillae
network of blood vessels between reticular layer + hypodermis
Cutaneous Plexus
The two types of hair
Vellus hair
Terminal hair
hair thinning after 40
Alopecia
genetically determined condition
True baldness
caused by a follicular response to (dihydrotestosterone)
Male pattern baldness
hard keratin
Nails
Nail
Lanula
thickened portion of bed responsible for nail growth
Nail Matrix
cuticle
Eponychium
the skin just under the free edge of your nail
Hyponychium
bone of fingertip
Phalanx
on all skin surfaces except nipples and parts of genitals contain these
Sweat glands (sudoriferous glands)
2 Types of sweat glands
Eccrine and Apocrine
- ducts connect to pores
- involved in thermoregulation
- abundant on palms, soles, and forehead
- secretion is: 99% water, salts, vit. C, antibodies, dermcidin, metabolic waster
Eccrine (merocrine (exocytosis) glands) sweat glands
- larger than eccrine glands
- also merocrine
- confined to axillary and anogenital areas
- secretes milky/yellowish sweat that contains fatty substances
- begin functioning at puberty
Apocrine sweat glands
- lines the external ear canal
- secretes cerumen (earwax)
Ceraminous glands
secretes milk
Mammary glands
- simple branched alveolar glands
- mostly around hair follicles
- not in this skin
Sebaceous Oil Glands
- oily holocrine secretion
- bactericidal
- softens hair and skin
Sebum
Skin functions
Protection
Body temp regulation
Cutaneous sensations
Metabolic functions
Blood reservoir
Excretion of wastes
unnoticeable sweat, 500 mL/day
Insensible perspiration
noticeable sweat, 12L(3 gal)/day
Sensible perspiration
- part of the nervous system
- exteroceptors respond to stimuli outside the body, such as temperature and touch
- free nerve endings sense painful stimuli
- exteroceptors respond to stimuli outside the body, such as temperature and touch
Cutaneous sensory receptors
caused by overexposure to UV radiation and frequent skin irritation
Skin cancer
3 Major Types of Skin Cancer
Basal cell carcinoma
Squamous cell carcinoma
Melanoma
- stratum basal cells proliferate and slowly invade dermis
- 99% cured by surgical excision
Basal cell carcinoma
- involves keratinocytes of stratum spinosum
- scaly reddened papule on scalp, lower lips, and hands
- good prognosis if treated by radiation or surgical excision
Squamous cell carcinoma
- cancer of melanocytes
- metastasizes+highly resistant to chemotherapy
- treated by wide surgical excision
Melanoma
What happens after a burn?
threatens dehydration and loss of electrolytes
leads to renal shutdown and circulatory shock
epidermal damage only
-localized redness, edema, pain
First degree burns
epidermal and upper dermal damage
-blisters appear
Second degree burns
skin color turns grey, white, cherry red, blackened
-no edema, not painful (nerve endings destroyed)
Third-degree burns
external ear glands that secrete wax
Ceruminous glands
Senses touch
Meissners corpuscle
Senses pressure
Pacinian corpuscle
Senses pain
Nociceptor
Involved in recognizing fine touch
Meissners corpuscle, merkels discs, root hair plexus
Temp and pain
Free nerve endings
