Title: Integument_review2021
URL Source: file://pdf.3f38f5ebd0c9bf2e1cb83903258785cf/
Markdown Content:
# The Integumentary System Review Skin (Integument)
Consists of two distinct regions:
Epidermis superficial region
Dermis underlies epidermis
Mostly fibrous connective tissue
Hypodermis (superficial fascia)
Subcutaneous layer deep to skin
Not part of skin but shares some functions
Mostly adipose tissue that absorbs shock & insulates Epidermis
Keratinized stratified squamous epithelium
Four or five distinct layers
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum lucidum (only in thick skin)
Stratum corneum Epidermis
Four cell types
Keratinocytes
Melanocytes
Dendritic ( langerhans ) cells
Tactile ( merkel ) cells Dermis
Strong , flexible connective tissue
Cells - Fibroblasts , macrophages, and occasionally mast cells and white blood cells
Fibers in matrix bind body together
Contains nerve fibers; blood and lymphatic vessels
Contains epidermal hair follicles; oil and sweat glands
Two layers
Papillary
Reticular Skin Color
Three pigments contribute to skin color
Melanin
> Only pigment made in skin
Carotene
Hemoglobin Appendages of the Skin
Hairs and hair follicles
Nails
Sweat glands
Sebaceous (oil) glands Sweat Glands
Also called sudoriferous glands
All skin surfaces except nipples and parts of external genitalia
~3 million per person
Two main types:
> Eccrine (merocrine) sweat glands
> Apocrine sweat glands
Contract upon nervous system stimulation to force sweat
into ducts Sweat Glands
Eccrine Sweat Glands
Most numerous
Abundant on palms, soles, and forehead
Ducts connect to pores
Function in thermoregulation
Regulated by sympathetic nervous system
Their secretion is sweat
99% water, salts, vitamin c, antibodies, dermcidin (microbe -killing peptide), metabolic wastes
Apocrine Sweat Glands
Confined to axillary and anogenital areas
Sweat + fatty substances + proteins
Viscous; milky or yellowish
Odorless until bacterial interaction body odor
Ducts empty into hair follicles
Begin functioning at puberty
Function unknown but may act as sexual scent gland
Modified apocrine glands
Ceruminous glands lining of external ear canal; secrete cerumen (earwax)
Mammary glands secrete milk Sebaceous (Oil) Glands
Widely distributed
Not in thick skin of palms and soles
Most develop from hair follicles and secrete into hair follicles
Relatively inactive until puberty
Stimulated by hormones, especially androgens
Secrete sebum
Oily holocrine secretion
Bactericidal
Softens hair and skin Functions of the Integumentary System
Protection
Body temperature regulation
Cutaneous sensation
Metabolic functions
Blood reservoir
Excretion Skin Cancer
Most skin tumors are benign (not cancerous) and do not metastasize
(spread)
Risk factors
Overexposure to UV radiation
Frequent irritation of skin
Some skin lotions contain enzymes that can repair damaged DNA
Three major types of skin cancer
Basal cell carcinoma
Squamous cell carcinoma
Melanoma Melanoma
Cancer of melanocytes
Most dangerous
Highly metastatic and resistant to chemotherapy
Treated by wide surgical excision accompanied by immunotherapy
Key to survival is early detection ABCD rule
A: asymmetry; the two sides of the pigmented area do not match
B: border irregularity; exhibits indentations
C: color; contains several (black, brown, tan, sometimes red or blue)
D: diameter; larger than 6 mm (size of pencil eraser) Burns
Tissue damage caused by heat, electricity, radiation, certain chemicals
Denatures proteins
Kills cells
Immediate threat:
Dehydration and electrolyte imbalance
Leads to renal shutdown and circulatory shock
To evaluate burns
Rule of nines
Used to estimate volume of fluid loss Burns Classified by Severity
Partial -thickness burns
First degree
Epidermal damage only
Localized redness, edema (swelling), and pain
Second degree
Epidermal and upper dermal damage
Blisters appear
Full -thickness burns
Third degree
Entire thickness of skin involved
Skin gray -white, cherry red, or blackened
Not painful (nerve endings destroyed) or swollen
Skin grafting usually necessary Treatment includes
Debridement (removal) of burned skin
Antibiotics
Temporary covering
Skin grafts