Integumentary Flashcards
Major functions of the integumentary system
- Protection
- Sensation
- Vitamin D production
- Temperature regulation
- Excretion
The skin serves as the primary defense against offending microorganisms. It provides a barrier against ultraviolet light and helps maintain fluid inside the body, thus preventing dehydration.
Protection
Receptors in the skin makes it possible for human organism to perceive pain, pressure as well as other sensation like temperature changes.
Sensation
The body needs Vitamin D to help synthesize calcium absorption, made possible by the skin’s sufficient exposure to early sunlight.
Vitamin D production
The amount of blood flow beneath the skin’s surface and the activity of sweat glands in the skin both help regulate body temperature.
Temperature regulation
Small amounts of waste products are lost through the skin and in gland secretions.
Excretion
- The skin is a multilayered organ that consists of two main parts:
- Principal layers
- Epridermis
- Dermis
- made from keratinized stratified squamous epithelium, is the superficial, thinner portion of the skin that prevents water loss and resists abrasion. This is due to the process called “keratinization” , a process where cells undergo changes in shape and chemical composition to replace worn out cells.
- Superfical layer of the skin
- composed of 4-5 layers, depending on its location within the body
- palms and soles have five layers because there areas are exposed to most friction
Epidermis
instead, is the deeper, thicker, and dense connective tissue portion (figure 3.11). According to VanPutte, Regan, & Russo (2016), the dermis is responsible for most of the skin’s structural strength.
Dermis
What are the five layers of Epidermis?
- Stratum Basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
- also called the “stratum germinatum”, is the deepest layer that consists of either columnar or cuboidal cells aligned in a single row. Some cells in this layer are stem cells undergoing cell division to continually produce keratinocytes.
- Composed of single layer of cells in contact with the dermis
Stratum Basale
- 8 to 10 layers of many-sided keratinocytes that t closely together. This layer provides strength and flexibility to the skin. Cells in the more superficial portions of this layer are beginning to flatten.
- Cubodial or slightly flattened cells
- Spiny apprearance due to changed shape of keratinocytes
- With limited mitosis
- This layer plus stratum basale are collectively called Stratum Germinativum
Stratum spinosum
- 3 to 5 layers of flattened keratinocytes that are undergoing “apoptosis”. A distinctive feature of cells in this layer is the presence of the protein “keratin”
and membrane-enclosed lamellar granules. - Cells here appear granular due to the presence of keratohyalin granules
Stratum granulosum
- 4–6 layers of flattened clear, dead keratinocytes that contain large amounts of keratin. This layer is found only in the areas of the body (thick skin) where
exposure to friction is greatest (for example, fingertips, palms, soles, lips). - Nuclei, organelles, and cell membrances are no longer visible so this layed cppears clear
- Contains a transluscent substance called eleidin
Stratum Lucidum (Clear Layer)
- 25 to 30 layers of flattened dead cells from the deeper strata. The interior of the cells contains mostly keratin which aids in its natural strength. Its multiple layers of dead squamous cells filled with keratin help to protect deeper layers from injury and microbial invasion.
- This surface layer is cornified and is the real protective layer of the skin
- Cornification is brought on by keratinization and the hardening, flattening process that takes place as the cells die and are pushed to the surface.
- Friction at the surface of the skin stimulates additional mitotic activity of stratum basale, resulting in the formation of a callus for additional protection.
Stratim corneum
- is composed of dense collagenous connective tissue containing fibroblasts, adipocytes, and macrophages. Nerves, hair follicles, smooth muscles, glands, and lymphatic vessels extend into the dermis.
- Deeper and thicker than the epidermis
- A strong and stretchy envelope that helps to hold the body togather
- With numerous collagenous, elastic and reticular fibers that give support to the skin.
- Highly vascular and glandular
- Contains many nerve endings and hair follicles
Dermis
However, collagen fibers run through different directions making the skin to have tension lines or called?
Cleavage lines
- The uppermost portion of the dermis is called?
- It has a lot of blood vessels that keeps an avenue for providing nutrients, thermoregulation and elimination of wastes.
- in contact with epidermis
- Accounts for about 1/5 of the entire dermis
- With numerous projections called dermal Paplillae that extend from the upper portion of the dermis into the epidermis
- Dermal papillae contain capillary loops, which furnish nutrients to the epidermis.
Dermal papillae / Papillary layer
- The deeper part of the dermis, also known as the?
- attached to the subcutaneous layer, contains bundles of collagen and some coarse elastic fibers interspersed with adipose cells, hair follicles, nerves, oil glands, and sweat glands.
- Many phagocytes are found here; they engulf bacteria that have managed to get through the epidermis.
Reticular region / Reticular dermis
- plays responsible for its pale yellow to reddish brown to black shade produced by melanocytes of stratum basale. As evident, melanin is quite abundant in moles and freckles and in certain areas of the body like the nipples and areola.
- Guard skin against damaging effect of UV rays of sunlight
Melanin
- another pigment, produces a yellowish hue brought about by increase intake of carotene-rich foods such as squash and carrots.
- A yellowish pigment found in epidermal cells & fatty parts of dermis
- Abundant in skin of Asians
- Together with melanin, accounts for the yellowish-tan color of Asian
Carotene
were due to a drop of oxygen saturation in the blood, producing a bluish discoloration of the skin.
Cyanosis
- is an inherited trait that causes individuals to not produce melanin.
- There is a normal number of melanocytes but lacks enzyme tyrosinase, that converts the amino acid tyrosine to melanin.
Albanism
occurs due to melanin accumulation in patches.
Freckles
When the skin has portions that has complete or partial absence of melanocytes, irregular white spots are evident. this condition is termed as?
Vitiligo
- Deep to the dermis, but not part of the skin
- This layer consists of areolar connective tissue and adipose tissue.
subcutaneous layer
Parts of Hair
- Shaft
- Root
- Hair bulb Matrix / Matrix
- protects the skin and other structures of the body.
Hair and Pili
- is the superficial portion that projects bove the surface of the skin.
- The visible but dead portion of hair projecting above surface of the skin
Shaft
- is the portion below the surface that penetrates into the dermis and sometimes into the subcutaneous layer.
- enclosed in the follicle
Root
3 layers of hair in cross section
- Medulla
- Cortex
- Cuticle
- Growth zone; contains melanocytes that give color to hair
Hair bulb matrix / Matrix
A hair has a hard _________(thick middle part), which surrounds a softer center, the ___________ (inner).
Cortex and Medulla
The cortex is covered by the ____________, a single layer of overlapping cells that holds the hair in the hair follicle.
Cuticle
surrounds the root and is composed of epidermal cells.
Hair Follicle
are nerve endings that surround each hair follicle. They are sensitive to touch and are stimulated if a hair shaft is moved.
Hair root plexuses
Two major glands
Sebaceous glands
Sweat glands
- lies in the dermis and opens into hair follicles or directly onto the skin. It secretes “sebum” as an oily substance that contains lipids and cellular debris.
- found all over the skin, except on palms and soles
-Ducts usually empty into a hair follicle but some open directly onto skin surface
Sebaceous glands
- The skin of an adult individual contains 3 to 4 million of this
- as it appears to be the most numerous of the skin glands. During active movements, the body loses about 500ml of insensible perspiration that doesn’t make the skin feel damp.
Sweat glands or Sudoriferous
Glands
There are two types of sweat glands
- Eccrine glands / Merocrine Gland
- Apocrine glands
- produces a transparent, watery fluid called “sweat” that contains small amount of potassium, ammonia, lactic acid, uric acid and other wastes.
- Secretion is mostly water with few salts
Eccrine glands / Merocrine Sweat Gland
- is limited to the axillary and pubic regions and produces a thicker sweat often released during emotional stress.
- Responsible for body odor
Apocrine gland
are plates of tightly packed, hard, dead, keratinized cells of the epidermis. Functionally, it helps us grasp and manipulate small objects, provide protection to the ends of the fingers and toes, and allow us to scratch various parts of the body.
Nails
Parts of nails
- Nail body
- Nail root
- Nail matrix
- Nail bed
- Free edge
6.Hyponychium - Eponychium (cuticle)
- Lunula
is the externally visible portion of the nails
Nail body
- Proximal part of the nail bed
- growth area of the nail
Nail Matrix
is covered and extends to the nail matrix.
Nail root
is stratum corneum that extends onto the nail body.
cuticle or eponychium
- The nail also attaches to the underlying ________, which is located distal to the nail matrix.
- Where nail root and nail body are attached
Nail bed
can be seen through the nail body as a whitish, crescent- shaped area at the base of the nail.
Lunula
- the distal exposed border attached to undersurface of hyponychium
Free edge
Beneath free edge
Hyponychium
Sensation receptor
- mechanoreceptors
- Meissner corpuscles
- Pacinian corpuscles
- thermoreceptors
- nociceptors
Sense of touch
mechanoreceptors
Skin movement and object handling detection
Meissner corpuscles
sensitivity to vibration, and deep pressure.
Pacinian corpuscles
able to detect heat and cold
Thermoreceptors
pain receptors
nociceptors
- Heaviest, largest single organ
- Also called integument, Cutaneous Membrane
- Simply means covering
Skin
SKIN APPENDAGES
A. Sweat Gland
B. Sebaceous Gland
C. Hairs
D. Nails
Functions of Integumentary system
- Keeps water and other precious
- Keeps water out
- Protects the body from external agent
- Insulated and cushions deeper body organs
- Protects body from mechanical, chemical, thermal damage and also bacteria
- Regulates heat loss from body surface
- Acts as mini-exretory system , urea, salt, water are lost when we sweat.
- Manufactures several proteins important to immunity
- Storgae of vitamin D precursor
- Contains cutaneous receptors that serve as sensors for touch, pressure, temperatire and pain.
Stratum Basale 4 types of Cells
A. Keratinocytes
B. Melanocytes
C. Tactile cells (Merkel Cell)
D. Non-Pigmented granular dendrocytes (Langerhan cells)
- Produce keratin which toughens & waterproofs skin
Keratinocytes
- Synthesize the pigment melanin providing a protective barrier to UV radiation in sunlight
Melanocytes
- Aid in tactile (touch) reception
Tactile cells (Merkel cell)
- Protective macrophagic cells that ingest bacteria & other foreign debris
Protective granular dendrocytes (Langerhans cells)
Coloration of skin
Cause by expression of a combination of 3 pigments
3 pigments of skin
- Melanin
- Carotene
- Hemoglobin
- Not a pigment of the skin, rather it is the oxygen-binding pigment found in RBc
- Oxygenated blood flowing through the dermis gives the skin its pinkish tones
Hemoglobin
Congenital Patterns
- Congenital Patterns
- Acquired Lines
- Langer Lines
- Fingerprints or friction ridges
- present on palms and soles
- formed by the pull of elastic fibers within the dermis
- function to prevent slippage when grasping objects
Congenital patterns
- Deep Flexion Creases
- Found on the palms
- Shallow Flexion Lines
- seen on knukles and surface of other joints
Acquired lines
- Lines of tension in the skin produces by the orineation of collgen aand elastic fibers in nonrandom pattern or arrangement.
- Surgical incision shuold be made parallel to this lines to promote better wound healing
Langer Lines
Layers of Dermis
- Papillary Layer
- Reticular Layer
- Found within the breasts
- Specialized sudoriferous or sweat gland that secrete milk during lactation
- Under the stimulus of pituitary gland
Mammary Gland
3 Distinct kinds of hair in human
- Lanugo
- Angora
- Definitive
- Fine, siilky fetal hair that appears during the last trimester of development
- Usually not evident on a baby at birth unless it has been born prematurely
Lanugo
- grows continuously in length, as on scalp and on face of males
Angora
- grows to a certain length and then ceases to grow
- most dominant type of hair (ex: eyelashes, eyebrow, pubic, and axillary hair)
- A sebaceous glands and an arrector pili muscle are attached to the hair follicle
- When the muscle involuntarily contracts due to to themal or psychological stimuli, the hair follicle is pulled into an upright position, causing the hair to “stand on its end” and producing “goosebumps”
Definitive
Fingernails grow at approximately ?
1mm per week
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