Transcript defensin - FTHS Wiki

Function and Dysfunction
of the Integumentary System
Functions of the Integumentary
System
1. Protection – chemical, physical, and biological
barrier
A. Chemical Barriers:
– Melanin defends against UV
– Skin secretions prevent infection:
• sebum: fatty acids w/ mild antibacterial and antifungal
properties
• defensin and cathelicidins (antibiotics) made by wbc
– Puncture membranes of bacteria
• Low pH (acidic) denature proteins
• High salinity dehydrate pathogens
Functions of the Integumentary
System
1. Protection – chemical, physical, and biological
barrier
B. Physical Barriers:
– Skin continuity
SEM of keratin taken from thumb
– Hardness and thickness of keratin
– Glycolipids made by s. granulosum waterproofs the
skin
Functions of the Integumentary
System
1. Protection – chemical, physical, and biological
barrier
C. Biological Barriers:
– Langerhan’s Cells and Macrophages activate the
immune response
– DNA has ability to absorb UV light and dissipate it into
harmless heat
“auras” captured with specialized
equipment may be due to DNA
vibrating at differing frequencies
(not yet proven)
Can we photograph the human
“soul?”
Functions of the Integumentary
System
2. Body temperature regulation
– Dilation of dermal blood vessels (cool)
– Constriction of vessels (conserves heat)
– Evaporation of sweat cools the body
pore
Functions of the Integumentary
System
3. Cutaneous sensation – receptors detect touch,
pain, and temperature
– Meissner’s corpuscles and Merkel disks: located in papillary
layer of the dermis detect lighter sensations
– Pacinian corpuscles: located in the hypodermis detect deep
pressure
– Ruffini’s corpuscles: detect heat and changes in
mechanics/movement
– Hair follicle receptors: respond to touch as hair bends
– Free nerve endings: sense pain and irritation
Functions of the Integumentary
System
4. Metabolic functions
– makes vitamin D from cholesterol in dermal blood
vessels
– Keratinocytes make enzymes that disarm cancer
causing chemicals that penetrate skin
5. Blood reservoir –skin vessels store up to 5% of
the body’s blood volume, to be used when
needed by organs
6. Excretion – small amounts of Nitrogenous
wastes are eliminated in sweat