Integumentary System Flashcards
(19 cards)
Introduction to the Integumentary Sytem
What are the organs of the Integumentary System?
What is Dermatology?
The organs of the integumentary systeminclude the skin
and its accessory structures, which include hair, nails, and
glands, as well as blood vessels, muscles and nerves
Dermatologyis the medical specialty for the diagnosis
and treatment of disorders of the integumentary system.
What are the Functions of skin?
- Thermoregulation
- Blood reservoir
- Protection
- Cutaneous sensations (touch, pressure, temperature, pain)
- Excretion and absorption
- Synthesis of vitamin D
Structure of the skin:
The ____ covers the body and…..
The area is about…
How thick?
The skin (cutaneous membrane) covers the body and is
the largest organ of the body by surface area and weight
Its area is about 22 square feet and 10-11 lb, about 7% of body weight. It is thinnest on the eyelids, thickest on the heels.
Structure of Skin:
What are the two major layers of skin called?
What is beneath the inner, thicker layer (the____)
It consists of two major layers:
- Outer, thinner layer called the epidermis, which consists of epithelial tissue
- Inner, thicker layer called the dermis
Beneath the dermis is a subcutaneous layer, called the hypodermis. It not part of the skin but, among its functions, it attaches the skin to the underlying tissues and organs
The Structure of Epidermis
What is it composed of?
How many major layers?
What are they?
The epidermis is composed of keratinized stratified squamous epithelium which is divided into four or five major layers:
(Deepest to superficial)
* stratum basale, (Deepest layer)
* stratum spinosum,
* stratum granulosum,
* stratum lucidum, (If only 4 layers, this isn’t present)
* stratum corneum (Most superficial layer)
Talk about thin, thick epidermis.
- Thin (hairy) skin covers all body regions except the palms, palmar surfaces of digits, and soles. 4 layers.
- Thick (hairless) skin covers the palms, palmar surfaces of digits, and soles. 5 layers.
How many major types of cells compose the epidermis?
What are they?
The epidermis contains four major types of cells:
Keratinocytes: 90% of the epidermal cells. Produce keratin which is a tough fibrous protein within the cells that provides protection.
Melanocytes: Produce the pigment melanin that protects against damage by ultraviolet radiation.
Langerhans cells: Also called intraepidermal macrophages. Involved in immune responses, arise from red bone marrow.
Merkel cells: Also called tactile epithelial cells. Function in the sensation of touch along with the adjacent tactile discs
Talk about growth/shedding of the epidermis
Growth and shedding of the epidermis:
Keratinization, the accumulation of more and more protective keratin, occurs as cells move from the deepest layer to the surface layer. Cells become less metabolically active and eventually die (apoptosis) as they move to the surface. 4-6 weeks.
Constant friction can stimulate the formation of a callus
Dandruff (flaky scalp) can be caused by too much keritanization in skincells of the scalp.
Structure of the Dermis
The dermis is composed of _________
It contains ____ major layers which are the?
The dermis is composed of connective tissue containing collagen and elastic fibers
It contains two layers :
- Superficial papillary region consists of areolar connective tissue containing thin collagen and elastic fibers, dermal papillae (including capillary loops), corpuscles of touch and free nerve endings
- Deeper reticular region consists of dense irregular connective tissue containing collagen and elastic fibers adipose cells, hair follicles, nerves, sebaceous (oil) glands, and sudoriferous (sweat) glands
Dermis
What is the term for stretch marks, when do they appear?
Term for tension lines? Indicate?
Whar form the basis for fingerprints? Purpose?
Striae or stretch marks can appear if the skin is stretched too much
Lines of cleavage is “tension lines” in the skin indicating the predominant direction of underlying collagen fibers
Epidermal ridges reflect contours of the underlying dermal papillae and form the basis for fingerprints (and footprints); their function is to increase firmness of grip by increasing friction
Structural Basis of skin colour
Variations of skin colour arise from?
Talk about it.
Variations in skin color arise from variations in the amounts of four pigments:
Carotene is a yellow-orange pigment stored in the dead layer
of the epidermis and fatty areas of the dermis and
subcutaneous layer in response to excessive dietary intake.
Hemoglobin is an oxygen-carrying pigment in red blood
cells.
Bilirubin is a yellow byproduct of red blood cell destruction,
and indicates liver disease (jaundice is the symptom) when
in excess.
Melanin, produced by melanocytes, produces a wide
variation in skin colour.
A _____ localized overgrowth of melanocytes is a ____ or ___?
What is Albinism? Vitiligo?
A benign localized overgrowth of melanocytes is a nevus or mole
Albinism is an inherited inability to produce melanin
Vitiligo is a condition in which there is a partial or
complete loss of melanocytes from patches of skin
What are the accessory structures of skin?
Hair, skin glands, nails
Hairs or () have a number of important functions:
Hair is composed of?
Different types of hair?
Hair colour is determined by?
Hairs (pili) have a number of important functions:
* Protection
* Reduction of heat loss
* Sensing light touch
Hair is composed of columns of dead, keratinized epidermal
cells
There are different types of hairs including:
* lanugo
* terminal hairs
* vellus hairs
Hair color is determined by the amount and type of
melanin
Hair consists of?
What type of glands are connected to hair follicles?
Hair consists of:
* Shaft which mostly projects above the surface of the
skin
* Root which penetrates into the dermis
* Hair follicle
* Epithelial root sheath
* Dermal root sheath
Sebaceous (oil) glands are connected to hair follicles.
Arrector pili muscle(smooth muscle) associated with the dermal root sheath
Skin glands:
What are the skin glands and what do they do?
Sebaceous (Oil) glands secrete an oily substance called sebum
which prevents dehydration of hair and skin, and inhibits
growth of certain bacteria. Associated with hairs.
Sudoriferous (Sweat) glands:
* Numerous eccrine (or merocrine) sweat glands helps to cool the body by
evaporating, and also eliminates small amounts of wastes
* Apocrine sweat glands, located mainly in the skin of the
axilla, groin, areolae, and bearded facial regions of
adults, secretory during emotional stress
Ceruminous (Ear wax) glands are modified sweat glands
located in the ear canal producing a waxy secretion called
cerumen which provides a sticky barrier that prevents entry
of foreign bodies into the ear canal
Nails are composed of?
Each nail consists?
Nails are composed of hard, keratinized epidermal cells
located over the dorsal surfaces of the ends of fingers and
toes
Each nail consists of:
* a Free edge
* a Transparent nail body (plate) with a crescent-shaped
whitish lunula at its base
* a Nail root embedded in a fold of skin
Wound healing?
Proccess for epidermal wound healing?
- Epidermal stem cells detach
- They migrate then meet eachother
- contact inhibition-when they meet
- rapid cell growth, cells duplicate until wound is healed
Deep wound healing:
How many steps? What are they?
Four-step process:
1.Inflammation phase (For blood flow/clotting to stop bleeding)
2.Migration phase: migration of epithelial cells, called
epithelialization. (fibroblasts produce collagen which connects ends of wounds, scab is formed, under scab is called granulation tissue
3.Proliferation phase: is the increase of epithelial cells below the scab
4.Maturation (Scab falls off, skin heals until normal)
