INTEGUMENTARY SYSTEM
Epidermal Derivatives (Skin Appendages)
Hair: Nails: Exocrine glands:
Under normal conditions, some interstitial fluids slowly escape through the epidermis via a process called ______ water loss.
transepidermal
. Dermis
1. Middle layer 2. composed of dense irregular and areolar connective tissues 3. Contains nerve endings, hair follicles, & glands 4. Dermal papillae (projections of the dermis into the epidermis)
. Epidermis: (epi=on, derma=skin)
1. Outer layer 2. composed of keratinized stratified squamous epithelium 3. Avascular 4. Thick skin = 5 layers Thin skin = 4 layers
nails
1. formed from stratum corneum 2. Function: protection and grasping
Stratum Lucidum:
2-3 layers of dead, anucleated, keratinized, clear cells, only found on thick skin.
Stratum Corneum:
20-30 layers of dead, keratinized, anucleated cells (cornified = brittle, hardened); outer cells are constantly shed
. Melanocytes:
2nd most numerous; found in stratum basale w/ processes extending into the stratum spinosum. Produce melanin
Stratum Granulosum:
3-5 layers of flattened cells with visible granules; cells undergo keratinization here (keratinization = the process by which the nucleus shrivels up, cell dies, and cell fills up with the protein keratin)
Tactile Cells:
3rd most numerous; found only in the stratum basale; provide information regarding tactile (light touch) sensation
Epidermal Dendritic Cells:
4th most numerous; found primarily in the stratum spinosum; phagocyte
The integument accounts for about _____% of the body weight.
8
Layers of the Integument
Epidermis and Dermis
Which best describes the differences between sensible and insensible perspirations produced by sweat glands in the skin?
Insensible is in the form of water vapor and cannot be seen while sensible contains water and salts and can be seen. Insensible can be visible while sensible cannot.
Cells of the Epidermis
Keratinocytes, Melanocytes, Tactile Cells, Epidermal Dendritic Cells
A. Hair:
Made by the hair follicle . 3 parts: bulb, root, and shaft 2. Arrector pili muscle 3. Function: protect from sun damage and trauma. Also for heat retention.
Layers of the Dermis
Papillary Layer and Reticular Layer
Exocrine glands:
Sebaceous glands, Sweat (sudoriferous) glands,
Integumentary system =
Skin + Exocrine glands + Hair + Nails + associated nerves + associated blood vessels
Layers of Epidermis
Stratum Basale, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum, Stratum Corneum
Which are functions of the subcutaneous layer? Select all that apply.
Thermal insulation Protection Energy reservoir
Which of the following cells is found only in the stratum basale and is a light touch receptor?
a. Tactile Cell
Sebaceous glands = Oil (= sebum) glands
a. associated with hair follicles b. Functions: soften the skin & bactericidal
2. Mammary glands
a. modified sweat glands b. produce milk
Ceruminous glands (cerumen = earwax)
a. modified sweat glandsb. in external auditory canal c. cerumen can trap foreign particles and small insects, and it helps to keep the eardrum "soft'
The two types of connective tissue in the dermis are ______.
areolar and dense irregular
There are no blood vessels in the epidermis. The term for lack of blood vessels is ______.
avascular
The predominant type of protein fiber found in the dermis is ______.
collagen
Integument =
covering= skin (largest organ of body)
Another name for the skin is the ______ membrane.
cutaneous membrane
Reticular Layer:
deepest; composed of primarily dense irregular C.T., contains blood vessels; sensory receptors (neurons); secretory portions of glands; hair follicles; duct of glands
middle layer
dermis
The dermal papillae interlock with deep projections of the epidermis called ______.
epidermal ridges
outer layer
epidermis
The skin is made up of two distinct layers, the _____ and the _____.
epidermis, dermis
Friction ridges on the tips of fingers are known as ______.
fingerprints
b. Apocrine
i. axillary and pubic regions ii. Secretes onto hair roots iii. Releases odorous secretions called pheromones
a. Merocrine
i. found everywhere ii. releases perspiration (sweat) for thermoregulation. (regulates temp)
Keratinocytes:
most numerous; found in all layers; produce keratin
Subcutaneous layer (= hypodermis; superficial fascia)
not considered part of the integument. · Below dermis · Stores fat and anchors upper layers to other tissues · Composed of areolar CT and adipose CT
The ______ layer of the dermis contains areolar connective tissue and dermal papillae.
papillary
Stratum Spinosum:
several layers of polygonal-shaped cells with spines. Small degree of mitosis here.
Stratum Basale:
single layer of columnar/cuboidal cells resting on the basement membrane; cells are very mitotic
Papillary Layer:
uppermost; composed of areolar C.T. and dermal papillae; contains blood vessels; sensory receptors (neurons); portions of the ducts of glands and hair roots.
