Integumentary Flashcards
deeper layer of dense irregular connective tissue.
hypodermis
Cell of the epidermis undergo diff erentiation to form stratifi ed squamous kerati-nized epithelium.
keratinocytes (85% of the epidermis)
single layer of small, mitotically active basal cells that are attached by hemidesmosomes to underlying connective tissue and by desmosomes to each other.
stratum basale
Attaches basal cells to underlying connective tissue
Hemidesmosomes
Keratinocytes are attached to each other by
Desmosomes
located at the ends of their cytoplasmic processes containing keratin fi laments
Desmosomes
contains several layers of larger keratino-cytes
stratum spinosum
distinct layer of fl attened kerati-nocytes fi lled with keratohyalin granules
stratum granulosum
contain precursors to fi laggrin,
keratohyalin granules
when secreted, are responsible for the formation of the epidermal water barrier
lamellar bodies containing lipids,
most superfi cial layer of terminally diff erentiated squamous cells (with no nuclei) that are entirely fi lled with keratin fi laments.
stratum corneum
constantly desqua-mating from the skin surface.
terminally diff erentiated squamous cells (with no nuclei)
Total epidermal turnover time takes approximately
47 days.
(5% of cells in epidermis) reside in the stratum basale and have long processes that extend between keratinocytes into the stratum spinosum.
Melanocytes
Melanocytes synthesize and during the process of pigment donation, melanocytes transfer them into adjacent keratinocytes.
melanin pigment in melanosomes
Th e transferred pigment accu-mulates above nuclei of keratinocytes to
protect nuclear DNA from ultraviolet (UV) radiation and damage.
antigen-presenting cells involved in signaling of the immune system
Langerhans’ cells (2% to 5%)
mecha-noreceptor cells associated with sensory nerve endings.
Merkel’s cells (6% to 10%)
Th e dermis is composed of
papillary layer
reticular layer
con-sists of loose connective tissue (collagen I and III) that contains extensive plexus of blood, lymphatic vessels, and sensory nerve endings.
Papillary layer
composed of dense irregular connective tissue contain-ing type I collagen, elastic fi bers, and larger blood vessels.
Reticular layer
contain nerve endings and a network of blood and lymphatic capillaries.
Dermal papillae
The dermal papillae is found in
Th e epidermal–dermal junction
detect fi ne touch, heat, cold, and pain
free nerve endings in the epidermis
Merkel’s corpuscle (Merkel’s cell with a nerve ending) is a
sensitive mechano-receptor.
Encapsulated nerve endings matching type
- Pacinian corpuscles
- Meissner’s corpuscles
- Ruffini’s corpuscles
A. Detect pressure and vibrations
B. Detect light touch
C. Detect skin and torque
Epidermal stem cells responsible for diff erentia-tion into hair-forming matrix cells.
Follicular bulge
Hair is formed by
diff erentiation of matrix cells in the inferior segment to form the medulla, cortex (80% of hair mass), and cuticle of a hair shaft.
surrounded by the internal and external root sheath.
hair shaft
internal root sheath has three layers of cells:
Henle’s layer
Huxley’s layer, and
the internal root sheath cuticle
continuous with the epidermis.
external root sheath
produced by holocrine secretion and is discharged via pilosebaceous canal into the hair follicle.
Sebum
secrete protein-rich sweat into the hair follicles, but they are restricted to specifi c regions of the body
Apocrine sweat glands
Apocrine sweat glands are (anatomical classification)
coiled tubular glands with wide lumen
Their secretory parts contain_______ , the contraction of which is responsible for expression of sweat.
myoepithelial cells
produce sweat that is similar in composition to an ultrafi ltrate of blood in kidney.
Eccrine sweat glands
Eccrine sweat glands are related to hair follicles
T/F
False, not related
Eccrine sweat glands play a major role in
temperature regulation
through the cooling that results from the evaporation of water from sweat on the body surface.
plates of keratinized cells resting on nail bedscontaining hard keratin
Nails
As the nail plate grows, it moves under the nail bed with edges covered by skin folds.
T/F
Flase, over not under
