Exam 2 Study Guide: Chapters 5-8, Lecture Guide Pages 85-164
Anatomy and Physiology 1
Dr. Surmacz
Date of Exam: October 23, 2017
Chapter 5: The Integumentary System
2 Major Parts
o The skin (cutaneous membrane)
o Accessory structures
Hair, glands, nails, etc.
The Skin
o 2 Distinct Layers
Epidermis
Upper; thinner
Dermis
Deep; thicker
Hypodermis
AKA subcutaneous layer
OR superficial fascia
Not skin
Made of adipose and
areolar tissue
Anchors skin to
underlying organs
The Epidermis
o Stratified squamous epithelium
o Made up of cells called keratinocytes that make keratin
o Thick vs. Thin
Thick
.5 mm thick
5 layers
Found on palms and soles
Thin
.08 mm thick
4 layers
Found everywhere else
o Stratum Corneum
15-30 rows of dead flat cells that are interlocked by
desmosomes
Keratinized or cornification occurs
Water resistant, not waterproof
o Stratum Lucidum
Found in thick skin only
Clear, glassy layer
Flat, densely packed keratinocytes filled with keratin
o Stratum Granulosum
Cells start to die and dehydrate
Darkly stained layer containing 3-5 rows of keratinocytes
that have stopped dividing, cells grow thicker and flatter
, Exam 2 Study Guide 2
Synthesis begins of KERATOHYALIN and KERATIN, the
waterproofing proteins
o Stratum Spinosum
8-10 rows of spiny shaped keratinocytes held together by
desmosomes
Langerhans (dendritic) cells: immune function, defend
against bacteria
Stimulate against microorganisms that manage to
penetrate the superficial layers of the epidermis and
superficial skin cancers
Look like miniature pincushions
Contains cells that are involved in the immune response
o Stratum Germinativum or Basale
Single layer of stem cells capable of cell division
Attached to the
basement membrane (BM)
that separates
epidermis from dermis
Forms epidermal ridges
that extend into
dermis
Interlocks with the
dermis
Forms epidermal ridges
that are adjacent to
dermal projections
called dermal papillae
Has Merkel cells scattered among the basale cells
Contains melanocytes that produce melanin
o Takes about 7-10 days to go from stratum basale to corneum
o Takes a couple weeks for corneum cells to jump off
o Roles of the Epidermal Growth Factor (EGF)
Promoting the divisions of basal cells in the stratum
basale and stratum spinosum
Accelerating the production of keratin in differentiating
keratinocytes
Stimulating epidermal development and epidermal repair
after injury
Stimulating secretory product synthesis and secretion by
epithelial glands
o EGF can be used in tissue culture to stimulate the growth and
division of epidermal cells
The Dermis
o Made of connective tissue
o Contains networks of blood vessels, lymphatic vessels, and nerve
fibers
o Dermatitis is an inflammation of the skin that primarily involves
the papillary layer
o Papillary Layer
, Exam 2 Study Guide 3
Top, thinner
Composed of areolar connective tissue
Contains capillaries and sensory nerves
Contains fingerlike projections called papillae
Gives ridge like pattern to skin; fingerprints
o Reticular Layer
Composed of dense irregular connective tissue (collagen and
elastic fibers)
Contains sensory receptors (touch, temperature, pressure,
vibration, pain) and nerves
Contains blood vessels
Contains nerves
Contains hair follicles and glands
Fiber bundles responsible for lines of cleavage
o Collagen fibers are very strong and resist stretching, but they
are easily bent or twisted
o Elastic fibers permit stretching and then recoil to their
original length
When elastic fibers are overstretched, stretch marks result
o Bundles of fibers can be known as tension lines
Hypodermis
o The boundary between the hypodermis and the dermis is generally
indistinct because of the connective tissue fibers
o Very elastic
o Primarily adipose tissue, 80% of body fat
o Blood reservoir
Why doctors use hypodermic needles to inject drugs
Skin Color
o Due to interaction between: pigments in the epidermis and blood
flow in the dermis
o Melanin
2 kinds
Eumelanin
o Brown-black color
Pheomelanin
o Red-yellow color
The more melanocytes present, the darker the skin color
Is used for UV protection from the sun
o Carotene
Orange-yellow pigment that normally accumulates in
epidermal cells
An overabundance of carotene can give someone’s skin an
orange color
o Cyanosis
When the skin takes on a bluish color
o Disease-related changes in skin color
Jaundice
The liver is unable to excrete bile, so a yellowish
pigment accumulates in body fluids
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