Chapter 5 Flashcards
Hypodermis
The skin rests on this, it is like the foundation to a house, the hypodermis attaches to underlying bone and muscle and supplies to nerves and blood vessels
Consisted of loose connective tissue with collagen and elastin fibers
Contains mainly: fibroblasts, macrophages, and adipocytes
💥 hypodermis is not part of the skin, is sometimes called subcutaneous tissue or superficial fascia.
Half the body’s far is in the hypodermis
Dermis
The tissue layer connected to the hypodermis
Responsible for structural strength of the skin
Composed of: fibroblasts, adipose cells, connective tissue, macrophages
Divided into two layers
Epidermis
Is a layer of epithelial tissue that rests on the dermis
5 major functions of the integumentary system
- Protection- against abrasion, ultraviolet light, and prevents entry of microorganisms, prevents dehydration by reducing water loss
- Sensation- can detect heat, cold, touch, pain, pressure
- Temperature regulation- by controlling blood flow and sweat glands
- Vitamin D production- exposure to ultraviolet light makes vitamin D
- Excretion- waste is released through sweat glands
Two layers of the dermis
Reticular layer- deeper layer
Papillary layer- more superficial
Cleavage or tension lines
The elastin or collagen fibers are oriented more in some directions than others
Striae or stretch marks
If the skin is over stretched, the dermis may rupture and leave lines that are visible through the epidermis
Papillae
The papillary layer derives it’s name from projections called papillae that extend toward the epidermis
Keratinocytes
Responsible for structural strength and permeability characteristics of the epidermis.
Most cells in the epidermis are called this because they produce keratin
Melanocytes
Contain melanin and contribute to skin color
Langerhans cells
Are part of the immune system
Merkel’s cells
Specialized epidermal cells associated with nerve endings responsible for detecting light tough and superficial pressure.
Desquamate
As new cells are formed, they push older cells to the surface where they slough off, or desquamate
Keratinization
As cells move towards the surface of the skin to eventually fall off they change shape and chemical composition
Strata
On the basis of these stages the many layers of cells in the epidermis are divided into regions, or strata.
Five strata of the epidermis
Stratum corneum Stratum lucidium Stratum granulosum Stratum spinosum Stratum basale
Stratum basale
Cells divide by mitosis and some newly formed cells become the cells of the more superficial strata
Stratum spinosum
Keratin fibers and lamellar bodies accumulate
Stratum granulosum
Keratohyalin granules accumulate and a hard protein envelope forms beneath the plasma membrane, lamellar bodies release lipids; cells die.
Stratum lucidum
The cells are dead and contain dispersed keratohyalin
Stratum corneum
The dead cells have a hard protein envelope, contain keratin, and are surrounded by lipids.
Lamellar bodies
Additional keratin fibers and lipid-filled, membrane bounded organelles called lamellar bodies are formed inside the keratinocytes
Cornfield cells
Dead cells with hard protein envelope that are filled with protein keratin
Thick skin
Has all five epithelial strata, and the stratum corneum has many layers, thick skin is found areas subject to pressure or friction such as the palms of the hands, the soles of the feet, and fingertips.
Thin skin
Covers the rest of the body and is more flexible than thick skin is
Callus
In skin subjected to friction or pressure, the number of layers in the stratum corneum greatly increases to produce a thickened area called a callus
Corn
The akin over bony prominences may develop a cone-shaped structure called corn.
Melanin
Is the term used to describe a group of pigments responsible for skin, hair, and eye color.
Melanin also provides protection against ultraviolet light from the sun
Melanocytes
Melanin is produced by this,
They are irregularly shaped cells with many long processes that extend between the keratinocytes of the stratum basale and the stratum spinosum
Albinism
Usually is a recessive genetic trait causing an inability to produce tyrosinase
Melanosomes
The Golgi apparatuses of the melanocytes package melanin into vesicles called melanosomes which move into the cell processes of the melanocytes
Cyanosis
A decrease in blood flow such as occurs in shock can make the skin appear pale, and a decrease in the blood oxygen content produces cyanosis, a blueish skin color 💦💦💧🐬🐳🐟🐋☔️🌊😨💙💎🌀🏊📘📫📪📬📭💻🎐🗾🗻🚘🚙💺🚾🚰🅿️♿️🚭🈂Ⓜ️🛂🛄🛅🛃🏧💠➿🔵🔷🔹
Carotene
A yellow pigment found in plants such as carrots and corn, humans inject as a source of vitamin A. Carotene is lipid soluble so when large amounts are ingested excess can accumulate in the stratum corneum turning the skin yellow 🌟💫💛👑😮😬😶😯😑😧😦😟😖😆😏☀️⭐️⚡️🍋🌽🍌🍟✏️📒🚜⚠️🚕🚤🚚🏫🌞🌝🌛🌙🌜🌛🌕🐱🐤🐥
Lanugo
Delicate I pigmented hair that covers a fetus about 5-6 months along
Terminal hairs
Near the time of birth the lanugo falls out 💆💇💁 and terminal hairs grow on the scalp, eyebrows, and eyelids.
Vellum hairs
Replace lanugo and cover the rest of the body where the terminal hairs are not
Hair is divided into
The shaft and root
The hair shaft and root
What we can see above the surface of the skin
The root is under the skin
Hair bulb
At the base of the root
Three concentric layers of hair and their definition
Medulla- central axis of the hair, consisting of two or three layers of cells containing soft keratin
Cortex- forms the bulk of the hair and consists of cells containing hard keratin.
Cuticle- a single layer that forms the hair surface.
The hair follicle consists of two things?
Dermal root sheath and epithelial root sheath
Dermal root sheath
Is the portion of the dermis that surrounds the epithelial root sheath
Epithelial root sheath
Is divided into an external and internal part
Matrix
Inside the hair bulb is a mass of undifferentiated epithelial cells, the matrix, which produces the hair and the internal epithelial root sheath.
Growth stage
Hair is formed by cells of the matrix that differentiate, become keratinized, and die.
The hair becomes longer as cells are added at the base of the hair root
Resting period
Occurs after the growth stage in which growth ceases and when hair falls out and is being replaced
Arrector pili
Extend from the dermal root to the papillary layer of the dermis, normally hair follicles are at oblique angles. When the Arrector pili contracts it pulls the hair straight up. (Goose bumps)
Sebaceous glands
Located in the dermis and are simple or compound alveolar glands that produce sebum.
Two types of sweat or sudoriferous glands
Merocrine (eccrine)- most common type simple coiled tubular glands, responsible for cooling the skin.
Apocrine- responsible for body Oder
Isotonic fluid
Sweat, which contains salt, produced by the sweat glands
Ceremonious glands
Modified Merocrine sweat glands located in the ear canal and produces cerumen (earwax)
Cerumen
Earwax. Along with hairs it Protects the ear canal and eardrum by preventing the dirt of small insects.
Mammary glands
Modified apocrine sweat glands located in the breasts
Nail
Consists of the nail root and the distal nail body
Nail root
Covered by skin and the nail body is the visible potion of the nail.
Nail fold
The lateral and proximal edges of the nail are covered by skin called the nail fold
Nail groove
The sides are held in place by the nail groove, where hang nails form
Eponychium
Or cuticle, where the stratum corneum of the nail fold grows under the nail
Hyponychium
Beneath the free edges of the nail, skin under where nail is trimmed
Nail matrix
Where the nail root extend distally, under the lunula
Lunula
Seen through the nail body at the base of the nails on the thumb
Jaundice
A yellowing if the skin due to the accumulation of excess bile pigments in the blood stream
Impetigo
Usually affects children
Small blisters containing pus that easily rupture and form a thick yellowish crust
Erysipelas
(Streptococcus pyogenes) swollen red patches of the skin
Burns are often affected by what
Pseudomonas aeruginosa, which produces a blue- green puss caused by bacterial pigment
Acne
A disorder of hair follicles and sebaceous glands, the exact cause is unknown though
Well known infections of the skin
Chicken pox
German measles
Cold sores
Warts
Ringworm
A fungal infection that affects the keratinized portion of the skin, hair, and nails, produces patchy scaling and an inflammatory response
Decubitus ulcers
Also known as bed sores, Maggie in million dollar baby
Ischemia
Reduced circulation
Necrosis
Destruction of the hypodermis or deeper tissue which is followed by necrosis of the skin and one that occurs on the skin microorganisms can gain entry and produce ulcers
Bullae
Blisters
Psoriasis
Thicker than normal stratum corneum that sloughs to produce large silvery scales. If the scales are scraped away bleeding occurs from the blood vessels at the top of the dermal papillae
Eczema and dermatitis
General terms used for inflammatory conditions of the skin.
Strawberry brithmarks
A mass of soft elevated tissue that appears bright red to deep purple in color and usually disappear by age 7
Portwine stains
Appears as flat dull red or bluish patches that persist throughout life
Vitiligo
Development of patches of white skin because the melanocytes in the affected area are destroyed
Mole
Elevation of the skin that is variable in size and is often pigmented and hairy
Skin cancer
Most common type of cancer
Basal cell carcinoma
The most frequent skin cancer begins in the stratum basale and extends to the dermis to produce and open ulcer
Squamous cell carcinoma
Developed from stratum spinosum keratinocytes that continue to divide as they produce keratin, typically the result is a nodular, keratinized tumor confined to the epidermis, but it can invade the dermis, metastasize and cause death
Malignant melanoma
Less common form of skin cancer that arises from melanocytes usually in a preexisting mole.
Edema
A swelling of tissues
Debridement
The removal of dead tissue from the burn, helps prevent infection s by cleaning the wound and removing tissue in which infections could develop.
