chapter 5 Flashcards
integumentary system
Name 3 external functions of the skin.
Regulating body temperature
Protection
Excretion
Name 4 internal functions of the skin.
Sensation
Immunity
Blood reservoir
vitamin D synthesis
Name the 3 general layers of the skin
Epidermis
Dermis
Hypodermis
Describe the epidermis.
Top layer
Keratinized, stratified squamous
Avascular
Define epidermal growth factor
Protein hormone that stimulates growth and repair.
Name the 4 cells of the epidermis.
Keratinocytes
Melanocytes
Langerhans cells
Merkel cells
What are the layers of the skin (most superficial to most deep).
s. corneum
s. lucidum
s. granulosum
s. spinosum
s. basale
What is the function of keratinocytes?
Make waterproofing keratin protein.
What is the function of melanocytes?
Make melanin pigment protein.
What is the function of Langerhans cells?
Immune system activator
Skin dendritic cells
Migrate from bone marrow
What is the function of Merkel cells (aka: Merkel discs)?
They are also known as:
Where are they located?
Touch/light pressure receptors
Located in deep part of epidermis
Mechanoreceptors and Cutaneous receptors
Describe the s. corneum.
20-30 layers of flat, dead keratinized cells
cells slough off
replaced from below
Describe the s. lucidum.
3-5 layers of clear cells
extra protection on palms and soles of feet.
Describe the s. granulosum.
3-5 layers of cells
state of degeneration
Describe the s. spinosum.
8-10 layers of cells
mostly keratinocytes connected by desmosomes
Describe the s. basale.
“germinativum” layer
ONE single layer of stem cells
active mitosis forms keratinocytes and melanocytes
Describe the dermis.
Below epidermis
Connective tissue w/ collagen and elastic fibers
Blood vessels (vascular)
Nerves, glands, and hair follicles
Cells have an ECM
Name the cells found in the dermis and their functions.
Fibroblasts
Macrophages
Adipocytes
Fibroblasts: Make connective protein fibers
Macrophages: immune function
Adipocytes: fat cells
What are the 2 regions of the dermis?
Papillary dermis
Reticular dermis
What tissue is found in the papillary dermis?
Areolar connective (loose).
What are 2 important features of the papillary dermis?
Dermal papillae
Meissner’s corpuscles
Bumpy “velcro”
Ridges create fingerprints
Dermal papillae
Tactile sensory receptors for touch and pressure
Meissner’s corpuscles
What tissue is found in the reticular dermis?
Dense, irregular connective tissue
Collagen and elastic fibers
What is an important structure found in the reticular dermis?
Pacinian corpuscles
Sensory receptors for deeper pressure
Pacinian corpuscles
Describe the tissue of the hypodermis.
Superficial fascia and adipose tissue
What is the purpose of the hypodermis?
Bind reticular layer to underlying organs.
Brown/Black pigment from tyrosine
Melanin
___ is secreted by melanocytes.
Melanin
What determines color:
amount of pigment or cell number?
Amount of pigment
What is the function of melanin?
To protect against UV rays/decrease UV ray absorption.
Freckles and age spots can be attributed to ___.
melanin
___ is the lack of melanin.
Albinism
They are sensitive to UV light
___ is a pigment found in plants.
Carotene
Yellow, orange pigment.
Carotene
Precursor of vitamin A.
Carotene
What is the main pigment found in blood?
Hemoglobin (Hb)
Hemoglobin gives a “pink” color when exposed in the ___ ___.
dermal capillaires
Blue-ish complexion due to Hb being depleted of O2.
Cyanosis
Yellow-ish complexion due to increased heme recycling and increased bile derivatives.
Jaundice
___ are epidermal derivatives and associated structures.
Appendages
Hair provides __ and decreases ___ ___.
protection
heat loss
Define hair.
Columns of dead keratinized cells
What are the three parts of hair?
Shaft: above surface
Root: below surface, but deep into dermis
3 layers of hair: cuticle (outer), cortex (middle), medulla (inner)
____ surrounds root of hair.
Follicle
What are the four parts of the hair follicle?
Bulb
Papilla
Arrector pili muscle
Hair root plexus
What is the function of the bulb of the hair?
Base of the hair
Houses papilla
Describe the tissue of the hair papilla.
Is there blood supply?
What happens here?
Areolar connective tissue
Blood vessels deliver nutrients
Where hair cells divide
What is the arrector pili muscle?
A smooth muscle bundle that straightens the follicle
Chill bumps
What is the hair root plexus?
Nerve endings to cause sensation.
What is the cause of male pattern baldness?
Genetics
An increase in a variation of testosterone that causes hair blood vessel constriction.
What is a treatment for male pattern baldness?
How does it work?
Rogaine.
Vasodilator of hair blood vessels.
What are the pigments that determine hair color?
Eumelanin and Pheomelanin
What pigment determines blonde/brown/black hair color?
Less eumelanin: blonde
normal eumelanin: brown
more eumelanin: black
Red colored hair is due to ____.
Pheomelanin deposits sulfur into the hair.
Does not protect from UV rays.
What is the cause of gray hair?
Decrease of melanin
What is the cause of white hair?
Air bubbles in between proteins fibers
What are sebaceous glands?
oil glands connected to hair follicles
Where are sebaceous glands located?
Everywhere EXCEPT palms of hands and soles of feet.
What do sebaceous glands make?
Sebum made of fats, cholesterol, proteins, and inorganic salts.
What is the function of sebum?
Moisturize hair
Decrease skin water loss
Decreasing bacterial growth
What are the two types of sudoriferous glands?
Eccrine
Apocrine
What are the general functions of the sudoriferous glands?
Body temperature regulation
Secondary waste elemination/removal
Found throughout the skin (a lot on palms and soles)
Directly open to epidermis
Eccrine sweat glands
