Chapter 5: Integumentary System Part 2 Flashcards
Hair production
Begins at the base of the hair follicle, deep in the dermis.
Hair papilla contains capillaries and nerves
Hair bulb and papilla produces a hair matrix.
A layer of dividing cells, produces hair structure and pushes hair out of the skin.
hair matrix
layer of epithelial cells at the base of the hair bulb in contact with the hair papilla
Medulla
Is the center of the hair that contains soft keratin
Cortex
Contain layers of hard keratin (surrounding the medulla)
Cuticle
Thin and tough and contains hard keratin. (surrounding cortex)
External root sheath
Extends from the skin surface to the hair matrix.
New hair growth cycle
The follicle becomes active
Produces new hair
Club hair is shed
Club hair
not growing
Attached to an inactive follicle.
Hair color- where are melanocytes located?
Produced by melanocytes in the HAIR PAPILLA (Hair matrix)
Hair color is determined by genes
Sebaceous Glands
Oil glands
They are holocine glands.
They discharge an oily lipid secretion into hair follicles by the rupture of secretory cells.
Gland cells produce large quantities of sebum (lipids)
Sebum
Oily lipids
Protect and lubricates the epidermis
Inhibits bacteria
How is the secretions of sebum stimulated?
It is stimulated by hormones which are inactive in childhood and activated in puberty.
Seborrhea
Fast growing sebum
Over-active sebaceous glandsW
Whitehead
Sebaceous gland duct blocked by accumulated sebum
Blackhead
Sebum in the whitehead dries up and is oxidized.
Acne
Inflammation of the sebaceous gland
Accompanied by pimples
Secondary to bacterial infection.
exocrine gland
Empty though ducts to the epithelial surface.
Merocrine (eccrine gland)
Clear and watery
Location: Palms, soles, and forehead.
Mode of secretion: Exocytosis, directly onto the skin.
Sensible perspiration
water, salts, and organic compounds.
What are the functions of merocrine glands?
cools skin, excretes water and electrolytes, and flushes microorganisms and harmful chemicals from the skin.
Apocrine Gland
exocrine, secretion directly to the hair follicle.
Location: around the nipples, pubic region, and armpits.
Products accumulate just below the free surface and the apex of the cell pinches off. Secretory granules and a small amount of cytoplasm is released
What do the secretions of apocrine contain?
components of true swear, fat and proteins.
Stinky and cloudy secretions.
Breakdown causes odor.
Surrounded by myoepithelial cells.
In response to hormonal or nervous signals.
Ceruminous Glands
Location
Product
Function
Location: modified apocrine glands in the external ear canal.
Product: cerumen (earwax)
Function: protection of eardrum
Mammary glands
Location
Product
Function
Location: breast
Product: milk
Function: feeding
Autonomic nervous system
controls sebaceous and apocrine glands.
work simultaneously over the entire body.
How are merocrine sweat glands controlled?
controlled independently
sweating occurs locally
Thermoregulation
Main functions of sensible perspiration
works with the cardiovascular system
regulated body temperature.
nails
protective coverings at the ends of fingers and toes that contain hard keratin.
Nail body
epithelial cells containing keratin.
Overlies the surface of the skin called nailbed
Basal cell carcinoma
least malignant
stratum basale cells proliferate and invade the dermis and hypodermis.
Slow growing
can be cured with surgical excision `
Squamous Cells Carcinoma
Arises from keratinocytes of stratum spinosum
scalp, ears, and lower lip.
Grows rapidly
Prognosis is good if treated by radiation therapy or removed surgically.
Melanoma
Most dangerous type of skin.
Asymmetry, Border, Color, diameter
Treated by wide surgical excision accompanied by immunotherapy.
survival is poor if the lesion is over 4mm thick.
1st degree burn
only the epidermis is damaged
Symptoms: localized redness, swelling and pain
2nd degree burns
Epidermis and upper regions of the dermis are damaged
Symptoms: mimic 1st degree but blisters also appear.
3rd degree burns
Involved the entire thickness of the skin
Symptoms: grey-white, cherry red, or black and there is no initial swelling or pain since the nerve endings are destroyed.
Burns are considered critical if
25% of the body has 2nd degree burns
10% of the body has 3rd degree burns
3rd degree burns are on the face, hands, or feet.
Why are burns that cover 20% of the body life threatning?
Fluid and electrolyte balance is compromised
Thermoregulation
Protection from infection
What are the 4 steps of repair of injury on the skin?
*Inflammation Phase
-Bleeding occurs at the site, and mast triggers an inflammatory response.
*Migration Phase
-Scab forms and the stratum basale migrates along the edges of the injury.
*Proliferation Phase
-Scab is undermined by epidermal cells migrating over the collagen fiber meshwork .
*Scarring Phase
-Scab shed and a shallow depression marks the injury site.
Gland
Cell or organ in the body that produces and secretes particular chemical substances (hormones) for use in the body.
Endocrine Gland
DUCTLESS
Secretions are hormones in the blood.
ex: pancreas, thyroid, and adrenal glands
Exocrine Gland
Empty through ducts to the epithelial surface.
ex: sweat, salivary, mammary and sebaceous
Merocrine Secretion
Products are secreted by exocytosis
Only the product gets out
thin
sweat or hormones.
Apocrine Secretion
Products accumulate just below the free surface.
Apex of cell pinches off
Secretory granules and a small amount of cytoplasm is released.
Milk and stinky sweat
Holocrine secretion
Products released by cell bursting, killing gland cells.
Then are replaced by stem cells.
Thick and sticky
Goblet cells.
