Chapter 5 - Integumentary System Flashcards
Integumentary system is composed of
Skin, hair, oil glands, sweat glands, nails, sensory receptors
Whats the largest organ of the body?
Skin - cutaneous membrane
Skin consists of 3 parts, what are they
Epidermis - superficial, thin, composed of epitherlial cells
Dermis - deeper layer, composed of connective tissue
Hyperdermis - subcutaneous later, consists of areolar and adipose tissue
Whats the purpose of the subcutaneous layer?
Storage layer for fat and contains large blood vessels that supply the skin
Contains nerve endings called lamellated pacinian corpuscles that are sensitive to pressure
Epidermis is composed of
Keratinized stratified squamous epithelium
Epidermis consists of 4 principal layers of cells:
Keratinocytes
Melanocytes
Intraepithelial macrophages
Tactile epithelial cells
What makes up 90% of epidermal cells
Keratinocytes
4-5 layers
Produce protein keratin
8% of the epiderma cells are
Melanocytes
Produce melanin
Long, slinder processes that extend between the keratinocytes
Melanin is what
a yellow-red or brown - black pigment that contributes skin color and absorbs damaging UV light
Intraepithelial macrophages are also called what and do what
Langerhans cells
Participate in immune responses mounted against microbes that invade the skin
Help recognize an antigen
Tactile epithelial cells
Contact the flattened process of a sensory neuron (nerve cell) - a structure called a tactile disc
These detect touch sensations
Epidermis has what 5 layers
Stratum basale Stratum spinosum Stratum granulosum Startum lucidum Stratum corneum
Stratum basale
Deepest layer
Cubodial or columnar keratinocytes
Stem cells
Stratum spinosum
Lies superficial to stratum basale
8-10 layers of many sided (polyhedral) keratinocytes
Provides strength and flexibility to the skin
Stratum granulosum
Middle part of the epidermis
3-5 layers of flattened keratinocytes that are undergoing apoptosis (programmed cell death)
Presence of keratin and membrane enclosed lamellar granules which release a lipid-rich secretion
This secretion regards loss of body fluids and entry of foreign materials
Stratum lucidum (clear cell layer)
Thick skin ares
Fingertips, palm, sole of foot
3-5 layers of flattened, clear, dead, keratinocytes containing lg amts of keratin
Stratum corneum
25-30 layers of flattened dead keratinocytes
Continuously shed and replaced
Contain mostly keratin
Protect deeper layers from injury and microbial invasion
What happens with constant exposure to friction
Callus
An abnml thickening of the stratum corneum
What is keratinization
As cells move one epithelial layer to the next, they accumulate more and more keratin
Dandurff
Shedding of an excessive amt of keratinized cells form the skin of hte scalp
Dermis is composed of
Connective tissue Collagen Elastic fibers Dermal papillae Blood capilaries Free nerve endings
The surface are of the dermis is increased by
Small fingerlike projections called the dermal papillae
The deeper part of the dermis consists of what
Dense irregular connective tissue
Consists of:
Collagen, elastic fibers, adipose cells, hair follicles, nerves, oil (sebaceous) glands, sweat glands
What does the combination of collagen and elastic fibers in the dermis do
Provide the skin with strength, extensibility, and elasticity
Extreme stretching of the skin can do what?
Produce small tears in the dermis causing striae or stretch marks on the skin surface
3 pigments that allow for skin colors are
Melanin
Hemoglobin
Carotene
Melanin is produced by what
Melanocytes in the epidermis
Stimulated by exposure to UV light
Loss of melanocytes = immune system malfunction where antibodies attack melanocytes
Skin cancer is caused by
Repeated exposure to UV light
Albinism is
The inherited inability of an individual to produce melanin
Vitiligo is
A condition in which partial or complete loss of melanocytes form patches of skin that produce irregular white spots
Freckles
Patches that accumulate melanin
Ages spots
Accumulations of melanin
Mole (nevus)
Round, flat, raised area w/ an outgrowth of melanocytes
Hemoglobin
Oxygen carrying pigment in RBC
Carotene
Yellow-orange pigment
Precursor of vit A
Accumulates in the stratum corneum
Fatty areas of the dermis and subcutaneous area
Tattooing
Permanent coloration of the skin where a foreign pigment is deposited with a needle into the dermis
It deposits the ink in the macrophages of the dermis
Body piercings
Insertion of jewelry through an artificial opening
Accessory structures of the skin develop from
The epidermis of an embryo
Hair, glands, nail
Hair and nails protect the body
Sweat glands help regulate body temperature
Hairs are present where
On skin surfaces except palm, fingers, soles and toes and widely distributed in scalp, eyebrows, and genitalia
What is hair made of
Tread of fused dead keratinized epidermal cells
Shaft and root
Shaft projects above the surface of the skin
Root penetrates the dermis and subcutaneous layer
Hair follicle
Surrounds the root, composed of 2 layers of epidermal cells
External
Internal
Surrounded by a connective tissue sheath
Hair root plexuses
Surround the hair follicle, consists of nerve endings sensitive to touch
Hair bulb
Enlarged base of the hair follicle
Papilla
Contains many blood vessels that provide nourishment for hair
Hair matrix
Region in the hair bulb which produces new hairs by cell division when older hairs are shed
Arrector pili
A bundle of smooth muscle cells associated with hairs that extend from the dermis to the side of the hair follicle
Goose bumps
Color of the hair is dependent upon
Melanin
Grey hair - decline in the synthesis of melanin
White hair - accumulation of air bubbles in the hair shaft
Hirsutism
Excessive body hair
Androgenic - alopecia
Pattern baldness
Glands - name the 3 types that have to do with the skin
Sebaceous
Sudoriferous
Ceruminous
Sebaceous glands are
Oil glands connected to the hair follicles
None found in the palm of the hand or sole of the foot
Secrete sebum - keeps hair from drying out, prevents excessive evaporation of water from the skin, keeps skin soft, inhibits the growth of certain bacteria
Blacades are
Enlarged sebaceous glands on the face d/t accumulation of sebum
How do pimples/boils develop
Sebum is nutritive to certain bacteria
Sudoriferous glands are
2 groups?
Sweat glands, they release sweat or perspiration into hair follicles or onto skin surface through pores (sweat pores)
Eccrine
Apocrine glands
Eccrine sweat glands
Secrete outwardly
Distributed throughout most rgns of the skin except margins of lips, nail beds of fingers/toes, glans penis, glans clitoris, labium minora, and ear drums
Secretory portion of the gland is located deep in the dermis and the excretory duct projects through the dermis and epidermis and ends as a pore (sweat pore) at the surface
Start to function soon after birth
Regulate body temperature through evaporation
Sweat consists of
Water, ions, urea, uric acid, ammonia, amino acids, glucose, lactic acid
Emotional sweating is
Cold sweat - the release of sweat in response to an emotional stress such as fear or embarrassment
Apocrine sweat glands are
Simple, coiled, tubular glands found mainly in the skin of the axilla(armpit), groin, areola of the breast and bearded regions of the face in men
The secretory portion lies in the subcutaneous layer and the excretory duct opens into the hair follicle
The sweat is slightly viscous, odorless, appears milky or yellowish in color
Contains same things as eccrine sweat plus lipids and proteins
Dont function until puberty
Do not regulate temp
Secrete sweat during sex
Ceruminous glands
Present in the external autitory canal (meatus)
Excrete cerumen (ear wax)
Ear wax prevents foreign bodies and water/bacteria/fungi from entering cells
Nails are
Plates of tightly packed hard dead keratinized cells
Nail body - visable, pink because of underlying blood capilaries
Nail bed - thickened area of stratum corneum that attaches the free edge to the fingertip
Free edge -
Nail root - the portion that is not visable
Nail root contains
Lunula - white semilunar area near the nail root
Nail matrix - proximal portion of the epithelium deep to the nail root
Cuticle consists of starum corneum
Functions of the skin
Regulation of body temp Protection Cutaneous sensations Excretion and absorbtion Synthesis of VitD
How does the skin regulate body temp
Sweat
Blood vessles dilate
Increasing heat loss
How does the skin offer protection
Keratin
Melanin
Hair
Nails
Intraepidermal macrophages alert the immune system
Macrophages in the dermis phagocytize baceria/viruses
How does the skin have cutaneous sensations
Tactile sensations (touch, pressure, vibration, tickling)
Thermal sensations (warmpth, coolness, pain)
Tissue damage = pain
How does the skin deal with excretion and absorption
Excretion - elimination of substances from the body
Absorption - passage of materials from the exterior into the body cells
How does the skin deal with synthesis of vit D?
Exposure of the skin to Ultraviolet radiation activates VitD which is converted to an active from by a hormone called calcitriol
When/Where does aging occur
After 40
In the proteins in the dermis
What happens to Collagen fibers, elastic fibers, fibroblasts, and intraepidermal macrophages with aging
Collagen fibers - decrease in number
Elastic fibers - lose their elasticity
Fibroblasts - decrease in number resulting to wrinkles
Intraepidermal macrophages - become less efficient phagocytes decreasing the skins immune response
Sebaceous glands - decrease in size leading to dry skin
Rosacea is a skin condition that
Affects mostly light - skinned adults between ages 30-60
Redness, tiny pimples, noticeable blood vessels
Central area of the face
