Integumentary System Flashcards
superficial layer of stratified keratinized squamous epithelium, avascular–supplied by blood vessels in dermis
epidermis
layer deep to epidermis, made up of areolar and dense irregular collagenous connective tissue, and contains follicles, glands, and blood vessels
dermis
layer deep to dermis, made up of areolar tissue with adipose tissue–often known as subcutaneous fat
hypodermis
produce keratin
keratinocytes
keratin is a protein that makes cells both ___ and ___, to protect skin from abrasion as well as prevent excess loss of body water
hard; waterproof
produce melanin–the pigment responsible for skin, hair, and iris color
melanocytes
dendritic cells that process antigens to present them to lymphocytes
langerhans cells
free nerve endings
unencapsulated sensory receptors
deepest epidermal layer attached to underlying dermis with one row of actively mitotic keratinocytes and melanocytes, Langerhans cells, Merkel cells, and free nerve endings
stratum basale
the stratum basale is made up mostly of ___ (cell type)
keratinocytes
the 2nd to deepest layer of epidermis that is composed of several layers of keratinocytes unified by desmosomes, it also contains melanocyte cell processes between keratinocytes
stratum spinosum
thick bundles of intermediate filaments made of pre-keratin attached to desmosomes are located within keratinocytes in the stratum ____
spinosum
irregular shaped cells found within the stratum basale with long cell processes extending into the stratum spinosum, and they produce a pigment that provides protection against ultraviolet light by absorbing it before it reaches underlying cells
melanocytes
vesicles filled with melanin granules are called ___
melanosomes
keratinocytes phagocytize the tips of melanocyte processes to acquire ____
melanosomes
melanin is regulated by what 3 things?
genetics, exposure to UV light, and hormones
How does exposure to UV light regulate production of melanin?
UV light darkens the melanin that is present and stimulates production of more melanin
How do hormones regulate production of melanin?
During pregnancy, melanin production increases as a result of increased levels of estrogen and melanin-stimulating hormone
Layer of the epidermis with 3-5 layers of cells–within cytoplasm of cells are lamellated granules and keratohyaline granules which are bound to the inner surface of the cells, thickening the plasma membrane and helping resist abrasions
stratum granulosum
granules that contain glycolipids secreted to waterproof the epidermis
lamellated granules
granules that will attach to pre-keratin filaments in order to form keratin
keratohyaline
In the stratum ____, cells die because they are far from the blood vessels in the dermis and are coated by the glycolipids secreted into extracellular space
granulosum
the layer of epidermis only within thick skin on the palms of hands and soles of feet that is 2-3 layers of dead cells that are filled with eleidin
stratum lucidum
a clear protein that is an intermediate form of keratin
eleidin
the outermost layer of the epithelium that is 20-30 layers of dead cells filled with keratin and melanin and surrounded by glycolipids
stratum corneum
the layer of the dermis that is made up of areolar connective tissue that contains blood vessels that supply the epidermis
papillary layer
projections of papillary layer of dermis that extend toward epidermis (no function)
dermal papillae
layer of the dermis that is made up of dense irregular collagenous connective tissue–it contains blood vessels, nerves, hair follicles, smooth muscle, and glands
reticular layer
____ are parallel, curving ridges in the dermis of thick skin that shape the epidermis into fingerprints and footprints
dermal ridges
The majority of collagen fibers in the dermis are oriented in one condition, which creates ____ lines in the skin
cleavage
also called subcutaneous tissue or superficial fascia, it connects dermis to underlying muscle and bone
hypodermis
The hypodermis is made up of ___ and ___ tissue
areolar and adipose
mechanoreceptors respond to
pressure, tension, stretching
chemoreceptors respond to
chemicals (O2, glucose, CO2, pH) and itch
thermoreceptors respond to
temperature
photoreceptors respond to
light
nociceptors respond to
pain
___ sit on top of free nerve endings within the epidermis and dermis
merkel disks
free nerve endings around a follicle are called
hair follicle receptors
Encapsulated cutaneous receptors located in the dermis–3 of them
Meissner’s corpuscles, Ruffini end organs, and Pacinian corpuscles
Free nerve endings have what 4 cutaneous receptors:
thermo, noci, mechano, and chemo
Merkel discs have ___ cutaneous receptors, which detect ___
mechanoreceptors–light touch and pressure
The cell bodies of merkel discs are located in the stratum ___
basale
Hair follicle receptors have ___ cutaneous receptors, which detect ____
mechanoreceptors–bending of hair
proteins within plasma membrane of free nerve endings that open ion channel gates (mostly Na and K) at different temperature ranges
transient receptor potential proteins
Meissner’s corpuscles have ____ cutaneous receptors which detect ___
mechanoreceptors–light touch and pressure and vibration
Pacinian corpuscles have ___ cutaneous receptors which detect ____
mechanoreceptors–deep pressure, stretch, and vibration
Ruffini endings have ___ cutaneous receptors which detect ____
mechanoreceptors–deep pressure and stretch
____ glands secrete onto an epithelial surface
exocrine
Sebaceous and sweat glands are ____ glands
exocrine
_____ are holocrine glands that secrete sebum into a duct that empties into a hair follicle
sebaceous glands
How does a holocrine gland excrete its contents?
the substance builds up in the cell, the cell dies and lyses, and the cell as well as its contents are excreted
The most common type of sweat gland
merocrine//eccrine
____ secrete water with salts (mostly Cl) and small amounts of ammonia, urea, uric acid, and lactic acid into a duct that empties onto the external surface of the epidermis
merocrine sweat glands
How does a merocrine gland secrete?
by exocytosis–the product moves out via a vesicle
___ secrete odorless, organic substances that are metabolized by bacteria to produce body odor into a duct that empties into a hair follicle in the axilla and perineum
apocrine sweat glands
How do apocrine sweat glands secrete?
via exocytosis, like merocrine glands
____ are apocrine glands located in ear canal with ducts that open either directly onto the surface of the external auditory canal or into the ducts of sebaceous glands
ceruminous glands
How do ceruminous glands secrete?
true apocrine secretion–secretions accumulate in cytoplasm, parts of the cell pinch off, pinched off portion is part of the secretion
____ are apocrine glands located in the breasts of female that secrete milk into ducts that empty onto the nipple
mammary glands
___ is a combination of water with antimicrobial proteins and sebaceous gland secretions
cerumen
The ____ of the hair is the most internal layer and contains soft keratin
medulla
The ___ of the hair contains hard keratin
cortex
The ___ of the hair is a single layer of cells on the hair surface
cuticle
The ___ of the hair follicle is a mass of undifferentiated epithelial cells similar to cells in the stratum basale of the epidermis, that becomes the hair and the internal epithelial root sheath
matrix
The ___ is part of the dermis that projects into the hair bulb and contains blood vessels that nourish the cells of the matrix
hair papilla
The most external layer of the hair follicle sheath that contains cells of the dermis is the ____
dermal root sheath
____ is formed by matrix cells that differentiate, become keratinized, and die
hair
Hair grows longer as cells are added to the ___
base
Body hairs normally have a growing stage and a resting stage, and after the resting stage what happens?
a new hair replaces the old hair
Smooth muscle attached to the hair follicle is the ___
arrector pili muscles
When arrector pili muscles are relaxed, hair is in what position?
hair is at an oblique angle to the skin
When arrector pili muscles are contracted, hair is in what position?
hair is pulled so that it is perpendicular to the skin
What causes goose bumps?
contraction of arrector pili muscles, pulling up on hair
Arrector pili muscles are innervated by ____ neurons
sympathetic
Nails are stratum ___ with ___ keratin
corneum; hard
The portion of the nail under the skin
nail root
The portion of the nail that is the external part of the nail
nail body
The part of the nail at the nail root that is epithelial tissue that produces new nail cells
nail matrix
The part of the nail under the nail body that is epithelial tissue that produces new nail cells
nail bed