Exercise 7- The Integumentary System
The accessory organs of the skin
1. Cutaneous glands 2. Hair 3. Nails
Two distinct regions of the skin
1. Epidermis 2. Dermis
Two primary regions of hair
1. Hair shaft 2. Hair root
Two dermis regions
1. Papillary layer 2. Reticular layer
Two primary categories of cutaneous glands
1. Sebaceous (oil) glands 2. Sweat (sudoriferous) glands
Five layers of epidermis
1. Stratum Basale 2. Stratum Spinosum 3. Stratum Granulosum 4. Stratum Lucidum 5. Stratum Corneum
Hair bulb
A collection of well-nourished epithelial cells at the base of the hair follicles.
Keratin
A fibrous protein that gives the epidermis its durability and protective capabilities.
Epidermis
A keratinized stratified squamous epithelium consisting of four distinct cell types and four to five distinct layers.
Sebum
A mixture of oily substances and fragmented cells that acts as a lubricant to keep the skin soft and moist and keeps the hair from being brittle.
Stratum Basale (basal layer)
A single row of cells immediately above the dermis. Its cell are constantly undergoing mitosis to form new cells.
Hair Follicle
A structure formed from both epithelial and dermal cells.
Stratum Granulosum (granulosum layer)
A thin layer named for the abundant granules its cells contain.
Acne
Acne is an active infection of the sebaceous glands.
Blackheads
An accumulation of dried sebum bacteria, and melanin from epithelial cells in the oil duct.
(Eccrine/Apocrine) glands are found primarily in the genital and axillary areas
Apocrine
_________ is a yellow-orange pigment found in the stratum corneum and the hypodermic. A. Keratin B. Carotene C. Melanin D. Hemoglobin
B. Carotene
Melanin
Brown-to-black pigment; Provides a protective pigment umbrella over the other layers of the epidermis.
These cells produce a brown-to-black pigment that colors the skin and protects DNA from ultraviolet radiation damage. These cells are: A. Dendritic cells B. Keratinocytes C. Melanocytes D. Tactile cells
C. Melanocytes
The portion of a hair that projects from the scalp surface is known as the: A. Bulb B. Matrix C. Root D. Shaft
D. Shaft
All of the following are functions of the skin except: A. Excretion body wastes B. Insulation C. Protection from mechanical damage D. Site of vitamin A synthesis
D. Site of vitamin A synthesis
The most superficial layer of the epidermis is the: A. Stratum Basale B. Stratum Spinosum C. Stratum Granulosum D. Stratum Corneum
D. Stratum Corneum
Reticular Layer
Deepest layer of skin.
The skin has two distinct regions. The superficial layer is the _____________ and the underlying connective tissue is the ________________.
Epidermis; Dermis
Sweat (sudoriferous) glands
Exocrine glands that are widely distributed all over the skin; Outlet known as pores.
Nail bed
Extension of the stratum basle beneath the nail.
Dermal Papillae
Fingerlike projections from its superior surface which attach to the epidermis layer and produce fingerprints.
Thick skin of the epidermis contains _____ layers.
Five 1. Corneum 2. Lucidum 3. Granulosum 4. Spinosum 5. Basale
Sebaceous (oil) glands
Found nearly all over skin; Their ducts usually empty into a hair follicle, but some open directly on the skin surface; Produce sebum.
Apocrine sweat glands
Found predominantly in the axillary and genital area; Secrete the basic components of eccrine sweat plus proteins and fat-rich substances; Produce B.O.
Eccrine sweat glands
Gland that produce clear perspiration consisting primarily of water, salts, and urea; Heat-regulating apparatus
Nails
Hornlike derivatives of the epidermis.
Hypodermis (superficial fascia)
Immediately deep to the dermis; Not considered part of the skin; Primarily consists of adipose tissue.
Keratinocytes
Keratin cells; Most abundant epidermal cells; Main function is to produce keratin fibrils.
Hair matrix
Layer of actively dividing epithelial cells that is located on tip of the hair papilla.
Tactile (Merkel) cells
Occasionally spiky hemispheres that, in combination with sensory nerve endings, form sensitive touch receptors called Tactile of Merkel discs located at the epidermal-dermal junction.
Skin
Organ that insulates and cushions the underlying body tissues and protects the entire body from abrasion, exposure to harmful chemicals, temperature extremes, and bacterial invasion.
Stratum Lucidum (clear layer)
Present only in thick skin. A very thin transparent band of flattened, dead keratinocytes with indistinct boundaries.
Eponychium
Projection of the thick proximal nail fold commonly called the cuticle.
Hair shaft
Region of the hair projecting from the skin.
Hair root
Region of the hair that is beneath the surface of the skin and is embedded within the hair follicle.
The ducts of (sebaceous/sweat) glands usually empty into a hair follicle but may also open directly on the skin surface.
Sebaceous
Stratum Spinosum (spiny layer)
Several layers of cells that contain thick, weblike bundles of intermediate filaments made of a pre-keratin protein; Cells appear to be spiky
Nail folds
Skin folds that overlap the borders of the nail.
Arrestor pili muscle
Small band of smooth muscle cells connect each hair follicle to the papillary layer of the dermis; Causes goosebumps
Melanocytes
Spidery black cells that produce melanin.
Papillary layer
The more superficial dermal region composed of areolar connective tissue.
Stratum Corneum (horny layer)
The outermost layer consisting of 20-30 layers of dead, scalelike keratinocytes.
Nail root
The part that is embedded in the skin and adheres to an epithelial nail bed.
Free edge
The portion of the nail that grow out away from the body.
Lunule
The proximal region of the thickened nail matrix, which appears as a white crescent moon.
Hyponychium
The region beneath the free edge of the nail
Nail matrix
The thickened part of the nail bed containing germinal cells responsible for nail growth.
Nail body
The visible attached portion.
True/False. Nails originate from the epidermis.
True