Chapter 5 Powerpoints Flashcards
what are the overview functions of the integumentary system?
regulation of temperature vitamin D production immunity protections excretion sensation
what are the epidermis, dermis, and subcutaneous?
Epidermis: Superficial layer of epithelial tissue.
Dermis: Deep layer of connective tissue.
Structural strength
Subcutaneous tissue
Not part of skin
Loose connective tissue that connects skin to underlying structures
what are the characteristics of epidermis?
Avascular; nourished by diffusion from capillaries of the papillary layer of the dermis
Composed of cells arranged into layers or strata.
Separated from dermis by basement membrane
Keratinocytes
Keratinocytes: most cells of the epidermis Produce keratin for strength
Langerhans’ cells:
part of the immune system
Merkel’s cells
detect light touch, and superficial pressure
Desquamate
cells of the deeper layers undergo mitosis; as they move toward the surface, older cells slough off
Keratinization
as cells move outward through the layers they fill with keratin, die, and
serve as a layer that resists abrasion and forms permeability layer
thick skin
Has all 5 epithelial strata
Found in areas subject to pressure or friction
Palms of hands, fingertips, soles of feet
Fingerprints and footprints. Papillae of underlying dermis in parallel rows
thin skin
More flexible than thick skin
Covers rest of body
Hair grows here
callus
Increase in number of layers in stratum corneum. When this occurs over a bony prominence, a corn forms
what 3 factors affect skin color?
pigments, blood circulating through the skin, thickness of stratum corneum
what is pigment?
Melanin: provides protection against UV light.
Production determined by genetics, hormones, exposure to light
Chemicals derived from tyrosine (tyrosinase is needed)
Colored brown to black, may be yellowish or reddish
melanocytes
Melanocytes. processes extend between keratinocytes.
albinism
Albinism: deficiency or absence of pigment (tyrosinase-)
Carotene
Carotene: yellow pigment. From vegetables. Accumulates in stratum corneum, in adipose cells of dermis, and in Subcutaneous tissue.
Blood circulating through the skin
Imparts reddish hue and increases during blushing, anger, inflammation
cyanosis
Cyanosis: blue color caused by decrease in blood oxygen content
what are the characteristics of dermis?
Gives structural strength.
C.T. with many fibers, fibroblasts, macrophages. Some adipocytes and blood vessels.
Contains nerves, hair follicles, smooth muscles, glands, and lymphatic vessels.
Sensory functions: pain, itch, tickle, temperature, touch, pressure, two-point discrimination.
stratum corneum
Most superficial and consists of cornified cells
lipids and dead cells
thick and thin skin is based on what layer of the skin?
epidermis
where can calluses and corns develop?
thick and thin skin
melanocytes
irregulary shaped cells with many long processes that extend between the kertainocytes of the stratum basale and stratum spinosum.
melanocytes also produce and package melanin into vesicles called melanosomes.
-contribute to skin color. Melanin produced by these cells then transferred to keratinocytes.
psoriasis
when large parts of epidermal tissue are sloughed off
stratum basale
Deepest portion of epidermis and single layer held by hemidesmosomes. High mitotic activity and cells become keratinized
- melanocytes
- cubodial or columnar cells
- desomosomes hold the keritnocytes together
stratum spinosum
Limited cell division. Desmosomes. Lamellar (lipid) bodies and additional keratin fibers
-shrink expecept where they are attached to desmosomes, so they look spiny
stratum granulosum
Contains keratohyalin in cytoplasm of the cell In superficial layers nucleus and other organelles degenerate and cell dies
-lamellar bodies make it to the cell
stratum lucidum
Thin, clear zone. Found only in palms and soles, thick skin
layers of dead cells
cornified cells
dead cells with a hard protein envelope, filled with keratin
erythema
condition in which the skin turns a reddish hue when the amount of blood flowing through the skin
pacinian corpuscles
deep pressure
meissner corpuscles
detecting simultaneous stimulating at 2 points on the skin
ruffini end organs
sensing continuous touch or pressure
papillary layer
Areolar loose CT with lots of elastic fibers
GRIP
contains blood vessels that give epidermis nutrients and oxygen.
Dermal papillae, capillary beds, Fingerprints. Whorls of ridges.
Touch receptors (Meissner’s), free nerve endings sensing pain
reticular layer
dense irregular CT
main layer of the dermis
irregular fibers that are resistant to stretching
subcutaneous layer main cells
fibroblasts, adiposytes, and macrophages
how much fat is in the subcutaneous layer
half
lanugo
unpigmented hair that covers the fetus
terminal hairs
pugmented hairs that replace the languno on the scalp, eyelids, and eyebrows
vellus hairs
short and fin, usually unpigmened cover the rest of the body
TERMINAL HAIR
REGULAR HAIR , reaplaces much of the vellus
eyelashed, scalp
where is hair produced
matrix
What type of cells does hair consist of
epithelial dead keratinized
what type of keratin does hair have
mostly hard
when does the hair fall out
hair falls out after resting period
most of the nail is produces by the
nail matrix
what conditions increase the amount of melanin?
All of these conditions increase the amount of melanin in the skin EXCEPT: exposure to ultraviolet light. pregnancy. Addison's disease. freckles.
what does the hair folicel contain?
The hair follicle
A) has an epithelial root sheath and a dermal root sheath. B) can provide epithelial cells for skin repair. C) contains only the stratum germinativum at the hair bulb. D) has an arrector pili muscle attached.
