Chapter 5 Anatomy Study Set

Integumentary System consists of

- Skin
- Hair
- Nails
- Sweat glands
- Sebaceous (oil) glands

What are two major types of skin

- Thick (hairless) skin
- Thin (hairy) skin

Thick (Hairless) Skin

- Covers the palms, planar surfaces of the digits, and planter surfaces (soles) of the feet

Thin (hairy) skin

- Covers most body regions

Major Functions of the Skin

- Prevents entry of toxic substances/patogens

- Reduces water loss

- Regulation of body temperature

- Contains sensory receptors and immune system cells

- Lipid storage

- Vitamin D synthesis (from cholesterol)

- Waste excretion

Skin consists of which two distinct regions

- Epidermis
- Dermis

Epidermis

- Superficial region
- Consists of epithelial tissue (stratified squamous) and is avascular

Dermis

- Underlies epidermis
- Areolar Connective Tissue is superficial to dense irregular Connective Tissue
- Vascular

Subcutaneous layer (Hypodermis)

- Mostly areolar connective tissue (collagenous & elastic fibers are continuous with those in dermis) & adipose tissue

- Anchors skin to underlying tissues and organs but is not technically part of the skin

Epidermis

- Thickness depends on location

What is the thickness of the epidermis on palms

0.8-1.4 mm

What is the thickness of the epidermis on soles

0.07-0.12 mm

What contains four layers (thin skin) or five layers (thick soles)

Epidermis

Hydrophobic Barrier

Secretion of proteins and lipids results in a tough

What does a loss of surface cells stimulate

Mitosis in cells of basal layer

What does Unusual friction/pressure lead to

Calluses/Corns

How many days does it take for cells to move to the surface

25-45 days

What does the Epidermis consists out of

Mostly keratinized stratified squamous epithelium

What are four types of cells found in the the epidermis

- Keratinocytes
- Melanocytes
- Dendritic (Langerhans) cells
- Tactile (Merkel) cells

Keratinocytes

Are the predominat cell type
- Stratified squamous epithelium
- Produce keratin (Protein) fibers

Melanocytes

Are pigment-producing cells

Epidermal dendritic (Langerhans) cells

Are antigen printing cells of immune system

Tactile (Merkel) cells

Are touch receptors at the base of the epidermis (Example: Finger tips)

What do Melanin (Pigment) produce cells within

Stratum basale

What do cellular extensions transfer pigment granules into

Epidermal cells

Skin color differences result from differences in the rate of?

- Melanin secretion NOT number of melanocytes

Melanocytes prevents damage to biological molecules from what being absorbed?

UV light (Exposure to UV-B stimulates melanogenesis)

Thick Skin

Contains five layers (strata) and is found in high-abrasion areas (hands, feet)

Thin Skin

Contains only four strata

Strata

Means Layers

What are the five layers of skin

- Stratum basale
- Stratum spinosum
- Stratum granulosa
- Stratum lucid (Only in thick skin)
- Stratum corneum

Stratum Basale

Deep, single layer of continuously dividing stem cells

Stratum spinous

Cells with weblike pre keratin filaments attached to desmosomes

Stratum Granulosm

- 3 to 5 layers of flattened cells with lamellated granules (secrete lipids) and keratohyalin granules (promote crosslinking of keratin)

Stratum Lucidum

Several rows of flat, dead cells seen only in thick skin

Stratum Corner

20 to 30 layers of dead, flat keratinized cells protect against abrasion, water loss, infection

What is the average thickness of the Dermis

1.0-2.0 mm

What is the dermis of the eyelids

0.5 mm

what is the dermis of the of the feet

3.0 mm

Papillary Layer is what type of tissue

Aerolar Connective Tissue

What does dermal papillae contain?

Capillary loops

What has free nerve endings

Meissner's corpuscles

Reticular Layer

Is dense irregular connective tissue

Collagenous and elastic fibers

Bind dermis to underlying tissues

What are smooth muscle fibers associated with

- Hair Follicles
- Glands
- Skin of scrotum

What do skeletal fibers anchored to dermis provide for

Voluntary movements (Examples: Facial Expressions)

Innervate dermal muscles & glands

Motor Neurons

Innervate sensory receptors (Examples: Touch, temperature, pain receptors)

Sensory Neurons

Hair (Pili)

- Tube-like structures, extend from the surface into the dermis (actually epidermal)

What do specialized epidermal cells form

- Keratinized
- Pigmented
- Dead epidermal cells

What is genetically determined

Pigment deposition by melanocytes

Arrector Pili

- Contracts
- Causes goose bumps (In response to cold, fear)

What does each follicle have and produce

- Oil producing
- (Sebaceous) glands

What does Epithelial cells of nail bed produce?

- Germinal Matrix
- Scale-like cells with lots of keratin

Nail Plate

- (Hard/translucent part of the nail)
- Is layers of keratin

Sweat (Sudorferous) glands

- Widely distributed
- Specialized epithelial cells secrete sweat
(Ex: H2O with salts and wastes including urea and uric acid)
- Merocrine or apocrine secretion

What are the two kinds of sweat glands

- Eccrine
- Apocrine

Eccrine Sweat Glands

- Most numerous/widely distributed
- Respond to high body temperature, emotional stress

Apocrine Sweat Glands; includes, responds, and breaks down what

- Axillary
- Groin
- Aerola regions
- Responds to emotional stress, sexual arousal
- Bacteria breaking down sweat leads to body odor

Ceruminous Glands

Lining of external ear canal; secrete cerumen (earwax)

Cerumen

Earwax

Mammary Glands

Secrete Milk

Sebaceous Glands

- Associated with hair follicles; specialized epithelial cells produce sebum (fatty material)