Integumentary System
Unit 2Chapter 5 in Textbook
https://www.youtube.com/watch?v=fXIcwm1oqQw
Integumentary- made up of
• Skin (epidermis, dermis, hypodermis)
• Hair• Nails• Glands(sudoriferous
, sebaceous, ceruminous
https://www.youtube.com/watch?v=AhbPPd-YeiU
8 Main Functions
1. Protection2. Sensation3. Excretion of wastes4. Synthesis of Vitamin D in sunlight5. Temperature regulation6. Coloration7. Waterproof8. Growth and repair
Skin Structure
3 MAIN Layers:1.Epidermis
a.Outer layerb.Stratified squamous tissue
2.Dermisa.Middle layerb.Thickest
3.Hypodermis (subcutaneous)a.Bottom layerb.Adipose tissue
http://science.nationalgeographic.com/science/health-and-human-body/human-body/skin-article/
Epidermis
➢Outermost layer
➢Made of keratinized
stratified squamous
tissue, so it:
● Many flattened
layers (mostly
dead)
● Lacks blood
vessels
Epidermis
➢There are 5 distinct
layers (deepest to
superficial)
● Stratum basale
● Stratum spinosum
● Stratum
granulosum
● Stratum lucidum*
● Stratum corneum
Epidermis
Stratum basaleDeepest layer- directly above the basement
membrane
Cells Types
Merkel Cells- function as touch
receptors in association with
sensory nerve endings
Epidermis
Stratum basaleMelanocytes-
produce the
brown pigment
melanin
Keratinocytes-
produce the
strong protein
keratin.
Simple cuboidal
Cells undergo mitosis here
Epidermis
Stratum spinosumLayers of rounded cells
with large nuclei
Cell types:
Langerhans’ cells-
macrophages that
help activate the
immune system
response
Epidermis
Stratum granulosum3-5 layers of flattened
granular cells
Keratinization process
here→ the process of
cells formed in the
stratum basale moving
up, flattening, dying,
and becoming hard
and waterproof
Epidermis
Stratum lucidum**Translucent layer**Only found in:
palms of hands & soles of feet
Not shown in textbook
Stratum corneumSuperficial layerDead, keratinized cells
Epidermis
Dermis
Dermis
2 Layers:1.Papillary layer-
connects to stratum basale
a.Dermal ridges-
allow us to grip
things
b.Creates
fingerprints & toe
prints
c.Loose areolar
connective tissue
Dermis
2 Layers:2. Reticular layer- connects to hypodermis
a.Sudoriferous & sebaceous glands, arrector pili muscle, nerves, blood vessels, & sensory receptors
b.Contains:i. Collagenous fibers: provide strength
ii.Elastic fibers: provide elasticity
iii.Reticular fibers: provide resilience
Hypodermis
AKA. Subcutaneous (Sub-Q)
Beneath the dermis
Made of adipose tissue
Insulation, protection, cushion
Accessory Organs
Accessory Organs
Hair
● Shaft: visible part of the
hair
○ Medulla: inner core of
the hair
○ Cortex: layer covering
medulla
○ Cuticle: Superficial
portion of hair
● Root: in dermis
Accessory Organs
NailsTightly packed, hardened, keratinized cells
Functions = manipulation and protectionMain parts:
nail plate cuticlelunulanail bed
Accessory Organs
Sudoriferous (sweat) Glands- 2 types
1.Eccrine-
a.most common
b.mainly in forehead, palms, & soles.
c.These function right at birth. -no odor in secretion (water plus salts)
2.Apocrine-
a.Mainly in armpits, groin, ear canals & breasts.
b.Begin to function at puberty.
Cermunious- secrete cerumen (ear wax)
Mammary- secretes milk in lactating females
Accessory Organs
Sudoriferous (sweat) Glands- 2 types
1.Eccrine-
a.most common
b.mainly in forehead, palms, & soles.
c.These function right at birth. -no odor in secretion (water plus salts)
2.Apocrine-
a.Mainly in armpits, groin, ear canals & breasts.
b.Begin to function at puberty.
Cermunious- secrete cerumen (ear wax)
Mammary- secretes milk in lactating females
Accessory Organs
Sebaceous (oil) GlandsConnected to every hair follicleSecrete sebum (oil) (keeps skin and hair
soft)Contains lysozyme-kills bacteria
Accessory Organs
Cutaneous Sensation1. Light touch detection:
a.Meissner’s
Corpuscles-located in
dermal papillae of
dermis
2. Pressure detection:a.Pacinian Corpuscles-
located deep in dermis
and subcutaneous
regions
Skin Color
1.Melanin- brown shadesa.Produced by melanocytesb.Same # in all races- just
darker skin have more active melanocytes
c.Determined by genetics (sun can play a small factor)
d.Albinism- lack enzyme tyrosinase which prevents melanocytes from being active
Freckles & moles – result from local
accumulations of melanin
https://www.youtube.com/watch?v=WwcVvrmALsI
Skin Color
2. Hemoglobin-reddish pigment responsible for the pinkish hue of the skin (protein found on red blood cells)
https://www.youtube.com/watch?v=WwcVvrmALsI
Body Temperature Regulation
Skin regulates temperature through blood vessels & sweating
Cold-muscles shiver and blood vessels constrict to increase body heat
Warm-vessels dilate increasing blood flow to skin which turns into sweating to release heat through evaporation
Wound Healing
1.Hemostasis- stop bleeding with clot
a.clot forms by constricting blood vessels
b.platelets come in to form “white clot”
c.fibrin threads make a spider-web like network to reinforce the area wounded
2.Inflammation-white blood cells remove bacteria and cellular debris
Wound Healing
3. Proliferation-new cells and fibers are deposited, new blood vessels form4. Remodeling-collagen and elastin fibers, cells no longer needed undergo apoptosis
Let’s Review!
What are the layers of the Epidermis from deep to superficial?
What is a burn?
A burn is a damage caused by the
intense heat
Chemical burns
Electricity
Radiation
Severe Burns Cause Immediate threat to life due to:
Dehydration and Electrolyte imbalance.
Can lead to renal shutdown and circulatory shock.
Burns
Concerns with burns:1.Heat loss- no barrier2.Fluid loss- no barrier3.Infection- open wounds
Burns
Evaluated by:1.% of body surface area burned2.Depth of burn
Burns
Estimating % of body surface area burned:
RULE OF 9’s (pg 167)11 areas of 9%=99%Genital is 1%Total area burned is
compared to the diagram to calculate a %
Must memorize
What type of Burns
1st Degree Burns
(typical sunburn)a.reddening of
skinb.may peelc.no blisteringd.“partial-
thickness
2nd Degree Burns
deep epidermis & upper dermis
- damage to sudoriferous & sebaceous glands, and hair follicles
2nd Degree Burns
- blisters, severe pain, & edema
scarring is common“partial-thickness
Third degree burn
Destruction of epidermis & entire dermistissue dies.May involve muscle or boneno pain due to nerves being burned off“full-thickness” burn
3rd degree Burns
Life-span changes of integumentary system
http://www.youbeauty.com/skin/aging-skinFibers lose elasticity-causing wrinklesSome melanocytes stop functioning-causes
gray hairSome melanocytes become more active-
causing liver spotsMitosis of skin cells slows down-healing takes
longerHair & nails take longer to grow due to dehydration