Pt 3. Integument Flashcards
Sensory Receptors are associated with ___
skin
Classification of sensory receptors by source of
information and ____
stimulus
3 Classifications of sensory receptor by source of information:
exteroceptors
proprioceptors
interoceptors
Source of information for: exteroceptors
(external environment)
Source of information for: proprioceptors
(position and movement of the body)
Source of information for: interoceptors
(internal organs)
Classification of sensory receptors by stimulus:
mechanoreceptors
thermoreceptors
nociceptors
Stimulus for: mechanoreceptors
respond to stretch, vibration, mechanical deformation
Stimulus for: thermoreceptors
- respond to cold or heat
Stimulus for: nociceptors
- respond to pain
most numerous, present in epidermis &
papillary dermis—surround most hair follicles
“free” N endings
“free” N endings lack ____ and are associated with ____
connective tissue capsules .. Schwann cells
What are merkel cells derived from?
Neural Crest
Serve multiple sensory modalities—hot/cold, touch, pain,
movement
Free N endings
What do merkel cells store?
serotonin
Pressure sensitive mechanoreceptors, associated with free
afferent N endings and ____
Merkel discs
–resemble keratinocytes
–found in stratum basale
of specialized areas of
the body such as
fingertips
–associated with the
basal lamina
–irregularly shaped
nucleus with granular
cytoplasm
Merkel cells
Look like melanocytes; located in stratum basale, contain
dense core granules, store serotonin
Merkel Cells
mechanoreceptors connected to a myelinated nerve fiber in
the ___
dermis
mechanoreceptors/ touch
receptors in dermal ridges
of papillary layer
Meissner’s corpuscles
–Especially prominent in
hands, feet, lips, genitalia
► Cylindrical structures ~ 150
m long
► Afferent N fibers associated
with minimally modified
Schwann cells
Meissner’s corpuscles
small
dermal mechanoreceptors,
especially common in soles
of feet
Ruffini corpuscles
mechanoreceptors located in
dermis & hypodermis
Pacinian corpuscles
Large, ovoid structures
(> 1 mm)
► Prominent in fingertips &
around joints—detect
mechanical & vibratory
pressure
► Consist of afferent N fibers
surrounded by highly
modified Schwann cells—
form concentric lamellae
separated by fluid-filled
spaces
Pacinian corpuscles
Hair is produced in ______
association with sebaceous
glands and a smooth muscle
bundle (arrector pili); these
can be called pilosebaceous
follicles or units
follicles
Hair shaft is covered by thin ____ of overlapping ___ plates; preventing matting
cuticle; keratin
a cortex of ____
forms the bulk of the hair
keratin
bundles of smooth Mm
cells (arrector pili M)
attach to hair follicle
sheath & insert on
epidermal ridges
piloerection
goosebumps
piloerection
Caused by ______
stimulation due to
cold/ fear/ aggression
sympathetic
in mammals, the function of
hair and fur is
thermoregulation, particularly
_____
heat conservation.
3 phases of hair growth:
Anagen, Catagen, Telegen (exogen=shedding)
Hair growth phases: a long phase of active growth
Anagen
Hair growth phases: a short phase of involution
catagen
Hair growth phases: and a short inactive involuted phase
telogen
Hair growth phases: Shedding of old hair shaft
exogen
Fine body hair in children
referred to as ____ hair
vellus
At puberty, vellus hair
replaced by coarser ____
terminal
hairs
Hair forms in the ___of epidermis
stratum basale
Hair forms via interaction with a hair germ cell and ______ from a dermal papilla
fibroblasts
A hair follicle is an ____ of epidermis
ingrowth
______ is capable of regenerating hair and sebaceous gland
follicular bulb
hair follicles are associated
with ____ glands and
______muscles
sebaceous gland and arrector pilli muscles
Contains natural pigment (melanin) and moisture
Cortex
The hair shaft is made up of
medulla and cortex
internal root
sheath is formed
by the ___
hair bulb
external root
sheath is formed
by ___
epidermis
Hair growth occurs here
hair bulb (root)
Hair bulb lined by
actively dividing
epithelial cells
homologous to
___
stratum basale
At base of bulb is a
vascular core AKA
dermal papilla
finger-like
invagination of dermis
containing blood
vessels
dermal papilla
As epithelial cells lining hair bulb
mature, fill with hard _____
arranged in parallel bundles
keratin filaments
Melanocytes adjacent to hair follicle
produce ______, becomes
incorporated into cortex => hair color
melanin
Developing hair surrounded &
protected by ___ and ____—line hair follicle
internal & external root
sheath
a modified
basement membrane, separates hair
bulb from surrounding dermis
Glassy membrane
aids in protection &
thermoregulation; absent on thick skin
of palms & soles
hair
The matrix cells in the hair bulb multiply and differentiate into the ___ with medulla cortex and inner and outer root sheaths
hair follicle
Hair follicle rooted in the ___
dermis
most common form of
hair loss, affecting 30-
40% of adults—genetic
and androgen
dependent
► Affected individuals
have high levels of 5-
α-reductase, the
enzyme that converts
testosterone to
dihydroxytestosterone
=> follicular atrophy
Androgenic alopecia
Alopecia: Affected individuals have high levels of _____, the enzyme that converts testosterone to dihydroxytestosterone
=> follicular atrophy
5α-reductase
Cutaneous horn are made of ___
keratin
Nail consists of flattened nail plate—rests on stratified squamous epithelium
of ___ (=hyponichium)
nail bed
Proximal end of nail,
____, extends into
dermis, attaches to
periosteum of distal
phalanx
nail root
Nail roots extends into demris and attaches to ____
periosteum
Nail growth occurs by
proliferation & differentiation
of epithelium at nail root in
germinative zone of ____
nail matrix
white crescent at
base of nail
lunula
lunula, covered by
superficial cuticle, or
___
eponychium
As epithelial cells mature, fill
with keratin & die, forming ____
nail plate
As nail plate ____ it slides over
underlying nail bed epithelium
grows
associated with
hair follicles or
empty directly
onto the skin
sebaceous glands
Glands producing sebum-a lipid-rich oily substance
Sebaceous glands
Sebaceous glands use ____ secretion
holocrine (entire cell breaks apart)
One or more glands assoc with each hair follicle; develop as outgrowths of external root sheath
**
Glands s ecrete oily sebum via
_____
pilosebaceous cana
Used for waterproofing,
moisturizing skin & hair
glands
Also found on non-haired
transitional skin—secrete
directly onto skin surface
glands
Seborrhea
an excessive secretion of sebum
Each hair follicle &
associated arrector pili M &
sebaceous gland =
pilosebaceous unit
coiled tubular glands
◦ long duct with
cuboidal epithelium
that empties into a
sweat pore
◦ merocrine secretion
eccrine/merocine sweat glands
located in specialized
areas and empty into
a hair follicle
Apocrine sweat glands
Types of Glandular secretions:
Holocrine, Merocrine, Apocrine
sweat glands—by
definition, secrete only
product
merocine (=eccrine)
In humans, merocine glands are distributed
over most of body
surface, except ___ and ___
lips &
genitalia
Merocrine glands are Unbranched, coiled, tubular glands with 1-2 layers of cuboidal to columnar epithelium with ___
excretory ducts
by definition, secrete
product along with
some cytoplasm
Apocrine sweat glands
Coiled, tubular glands
with large dilated
lumina
Apocrine Sweat glands
Located in axillae,
groin; develop at
puberty
Apocrine sweat glands
Type of epithelia in apocrine sweat glands
Secretory, cuboidal
epithelium, 2-3 cell
layers thick, surround
large glandular lumen
Discharge thick, viscid secretions into hair follicle—
Contain proteins, carbohydrates, ammonia, lipids, &
organic products
apocrine gland
In mammals, serves as sexual attractant, _______—
used in scent marking, territoriality
pheromone
Secretion in apocrine glands is
adrenergic
____ (wax) glands in external auditory meatus (ear
canal) are modified apocrine glands
Ceruminous
Important in thermoregulation for evaporative cooling
apocrine
