Integumentary System Flashcards
The principle organ of the integumentary system is the
skin
In addition to skin, what other structures would make up the integumentary system?
subcutaneous layer
hair
nails
a few types of glands
several NS receptors associated with the skin
Principle function of the integumentary system
PROTECTION - from trauma, infection
CONTAINMENT - keep other structures within our “shell”
TEMP. CONTROL - perspiration cools the body
CALCITRIOL SYNTHESIS - with sufficient sunlight
RECEIVE STIMULI - numerous receptors are associated with the skin
skin is the largest
organ in both surface and weight
two main parts to the skin
outer epidermis
deeper dermis
Epidermis
composted primarily of cells
made of epithelium
4 types of epidermal cells
keratinocytes
melanocytes
langerhans cells
merkel cells
keratinocytes
secrete keratin - a tough fibrous protein that protects and makes the skin waterproof
melanocytes
produce pigment melanin
langerhans cells
participate in immune responses against invading microbes and also susceptible to damage by UV rays
merkel cells
receive tactile stimuli
Kertinocytes of the epidermis are arranged in
several layers/strata
4 strata of thin skin
SUPERFICIAL TO DEEP:
corneum
granulosum
spinosum
basale
5 strata of thick skin
SUPERFICIAL TO DEEP:
corneum
lucidum
granulosum
spinosum
basale
strata from deepest to most supercial
basale
spinosum
granulosum
lucid (in thick skin only)
corneum
Stratum Basale
the deepest strata
undergoing constant cell division
Stratum Spinosum
8-10 layers of keratinocytes superficial to the basale
Stratum granulosusum
3-5 layers of flattened keratinocytes slowly undergoing apoptosis (pre-programmed cell death)
Stratum lucidum
only found in thick skin
consists of 4-6 layers of flattened, dead keratinocytes with large amounts of keratin
Stratum corneum
most superficial layer
consists of flattened, dead keratinocytes that are constantly shed and replaced by cells from deeper strata
The dermis
deeper portion of skin
consists of connective tissue with relatively few cells
many skin-associated structures (such as blood vessels, nerves, glands, and hair follicles) are embedded in the dermis
2 principal regions of the dermis
superficial papillary region
deeper reticular region
Papillary region of the dermis
Makes up about the upper 20% o the dermis
consists of bumps known as papillae
Some papillae contain ____ _____ and some contain _____
BLOOD CAPILLARIES;
RECEPTORS (meissners corpuscles, free nerve endings…)
The reticular region o the dermis
consists of dense irregular c.t.
anchored to the subcutaneous layer
Deep to the dermis is the. ____ _____ – also known as _____ _____
SUBCUTANEOUS LAYER;
SUPERFICIAL FASCIA
functions of the subcutaneous layer
ATTACH DERMIS/SKIN TO UNDERLYING STRUCTURES
SERVES AS PATHWAY FRO BLOOD VESSELS AND NERVES that extend into the skin
STORE FAT
SEVERAL DIFFERENT FACTORS influence skin color, but usually the most important factor is
MELANIN
two forms of melanin
PHEOMELANIN - yellow-to-red pigment
EUMELANIN - brown-to-black pigment
CAROTENE
a yellow-orange pigment that is a precursor from plants that may be used to make Vitamin A
the oxygen-carrying pigment in _______ in RBC’s can influence skin color in those with small amounts of melanin
HEMOGLOBIN
_____, also known as PILI, are found on most skin except for the….
HAIR;
PALMS, ANTERIOR SURFACE OF THE FINGERS, SOLES AND PLANTAR SURFACES OF THE FEET
components of hair include:
SHAFT - portion above the skin surface
ROOT - deep to the shaft, penetrates the dermis or subcutaneous layer
FOLLICLE - surrounds the root and consists of an external and internal root sheath
BULB - an onion-shaped structure around the base of the follicle
Types of hair
LANUGO HAIR
TERMINAL HAIRS
VELLUS HAIRS
LANUGO HAIR
downy hair on infants that is eventually shed and replaced by terminal or villus hair
TERMINAL HAIRS
long, coarse, heavily pigmented hairs that replace lanugo hairs o the eyebrows, eyelashes, and scalp before birth
VELLUS HAIRS
short, fine hairs that replace lanugo hairs over most of the rest of the body
HAIR COLOR is in great part due to the
AMOUNT AND TYPE OF MELANIN
dark hair = eumelanin
blond and red = variations of pheomelanin
gray hair = contains little melanin
white hair = lack melanin
Hair root plexi
free nerve endings wrapped around hair follicles and receive tactile stimuli when hair shafts are moved
ARRECTOR PILI MUCELS
extent fromt eh superficial dermis to the dermal root sheath at the side of the hair follicle
when contracted, hair shafts are pulled perpendicular to skin
SEBACEOUS GLANDS
exocrine glands that are ALMOST ALWAYS CONNECTED TO HAIR FOLLICLES (though some such as lips, genitals, and eyelids open directly to the skin)
sebaceous glands secrete
SEBUM - an oily substance that prevents skin and hair from drying out
SUDORIFEROUS GLANDS
produce SWEAT
coiled bases in the dermis with ducts that lead to the surface of the skin
two types of sudoriferous glands
eccrine
apocrine
Eccrine Sudoriferous glands
more common
found throughout the skin
main role is thermoregulation
apocrine sudoriferous glands
mainly in the skin of the axilla, groin, areaolaw, and the bearded region in males
can produce a musky odor
thermoregulatory sweating is primarily from
eccrine glands
emotional sweating is from
both eccrine and apocrine glands
sweating associated with sexual activity involves
apocrine glands
what are ceruminous glands
modified sudoriferous glands found in the EXTERNAL EAR CANAL
produce waxy lubricant knowns as CERUMEN
The NAIL BODY
the visible portion of the nail and is like the stratum corneum of the epidermis though the keratin is harder and not shed
LUNULA
the white portion of the nail body that has a thicker layer of epithelium deep to it that masks the blood vessels deep to it
FREE EDGE of nail
the portion that extends beyond the digit and appears white because there are no blood vessels under it
NAIL ROOT
the portion of the nail buried in a fold of skin
CUTANEOUS RECEPTORS
FREE NERVE ENDINGS
MERKEL DISCS
MEISSNERS CORPUSCLES
RUFFINI CORPUSCLES
HAIR ROOT PLEXI
PACINIAN
FREE NERVE ENDINGS
dendrites without any connective tissue capsules around them, and receive stimuli related to the sensations of temperature and pain
MERKEL DISCS
associated with Merkel cells in the stratum basale and have roles in receiving stimuli related to sensation of fine touch
MEISSNERS CORPUSCLES
are in the upper dermis and receive stimuli related to the sensation of fine touch
RUFFINI CORPUSCLES
usually located in the mid-dermis and receive stimuli related to the sensation of crude touch
HAIR ROOT PLEXI
free nerve endings wrapped around hair follicles and are related to the sensation of fine touch
PACINIAN
located deep in the dermis or subcutaneous layer as well as other tissues of the body and have a role in sensing deep pressure
