Ch 5 Flashcards
integumentary system
the integumentary system consists of the skin, hair, oil and sweat glands,
nails, and sensory receptors
the integumentary system contributes to homeostasis by protecting the body and helping regulate body temperature. It also allows you to sense pleasurable, painful, and other stimuli in your external environment.
dermatology
is the medical specialty that deals with structures, functions, and disorders of the integumentary system
cutaneous membrane (skin)
largest organ, 7% of total body weight in adult, thickness from 0.5mm- 4.0 mm
epidermis (superficial)
The superficial, thinner portion, which is composed of
epithelial tissue
function of the integumentary system
- Regulates body temperature.
- Stores blood.
- Protects body from external
environment. - Detects cutaneous sensations.
- Excretes and absorbs substances.
- synthesizes vitamin D
dermis (deep)
-deeper, thicker connective tissue portion
-composed of dense irregular connective tissue containing collagen and elastic fibers. It is divided into papillary and reticular regions. The papillary region contains thin collagen and fine elastic fibers, dermal papillae, and corpuscles of touch. The reticular region contains bundles of thick collagen and some coarse elastic fibers, fibroblasts and macrophages, adipose tissue, hair follicles, nerves, sebaceous (oil) glands, and sudoriferous (sweat) glands.
subcutaneous layer (hypodermis)
is deep to the dermis and not part of the skin, it anchors the dermis to underlying tissues and organs, and it contains lamellated corpuscles
hypodermis
consist of areolar and adipose tissues
lamellated corpuscles
The subcutaneous layer serves as a storage depot for fat and contains large blood vessels that supply the skin. lamellated corpuscles are nerve endings in this region, sensitive to pressure
epidermis
-the epidermis consists of keratinized stratified squamous epithelium
-an epidermal wound would not produce any bleeding.
-It contains four principal types of cells: keratinocytes, melanocytes, intraepidermal macrophages, and tactile epithelial cells
keratinocytes
cell in the epidermis 90% they are arranged in 4/5 layers and produce the protein keratin
keratin
tough fibrous protein that helps protect the skin and underlying tissues from abrasions, heat, microbes, and chemicals
intraepidermal macrophages ( langerhans cells)
arise from red bone marrow and migrate to the epidermis, participate in immune responses mounted against microbes that invaded the skin, are easily damaged by UV light
tactile epithelial cells ( merkel cells)
local to the deepest layer of the epidermis, contact the flattened process of a sensory neuron (nerve cell)
tactile disc (merkel disc)
detect touch sensation
thin skin
exposure to friction is greatest, in fingertips, palms, soles
thick skin
melanin
Melanin protects DNA of keratinocytes from the damaging effects
of UV light
stratum basale
the stratum basale is the layer of the epidermis with stem cells that continually undergo cell division
stem cells
stratum granulosum
keratohyalin
lamellar granules
stratum lucidum
stratum corneum
stratum spinosum
callus
keratinization
epidermal growth factor (EGF)
papillary region
dermal papillae
capillary loops
corpuscles of touch (meissner corpusles)
free nerve endings
reticular region
dermis
extensibility
elasticity
epidermal ridges
provide the basis for fingerprints and footprints
fingerprints or foot prints
structural basis of skin color
melanin, hemoglobin and carotene are three pigments that impart a
wide variety of colors to skin.
hair shaft
hair root
hair follicle
epithelial root sheath
dermal root sheath
hair bulb
papilla of the hair
hair matrix
hairs (pili)
are growths of epidermis composed of dead, keratinized epidermal cells
arrector pili
hair root plexus
sebaceous glands
oil glands
sudoriferous glands (sweat glands)
eccrine sweat glands
thermoregulation
thermoregulatory sweating
insensible perspiration
sensible perspiration
emotional sweating
apocrine sweat glands
sebum
cerumen
ceruminous glands
nails
nails are hard because they are composed of tightly packed, hard, keratinized epidermal cells
hyponychium
nail bed
eponychium
hangnail
nail matrix
free edge
nail root
lunula
nail body
functions of the nail
- the protect the distal end of the digits.
- They provide support and counterpressure to the palmar surface of
the fingers to enhance touch perception and manipulation. - They allow us to grasp and manipulate small objects, and they can
be used to scratch and groom the body in various way
Describe the structure of a hair. What causes “goose bumps”
Under physiological or emotional stress, such as cold or fright, autonomic nerve endings stimulate the arrector pili muscles to contract, which pulls the hair shafts perpendicular to the skin surface. This action causes “goose bumps” or “gooseflesh” because the skin around the shaft forms slight elevations
contrast the locations and functions of sebaceous (oil) glands,
sudoriferous (sweat) glands, and ceruminous glands.
what criteria are used to distinguish thin and thick skin
thermoregulation
excretion
absorption
blood reservoir
protection
cutaneous sensations
synthesis of vitamin D
in what two ways does the skin help regulate body temp
how does the skin serve as a protective barrier
what sensations arise from stimulation of neurons in the skin
what types of molecules can penetrate the stratum corneum
