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BIO 230
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Stanley Hall and Arthur Allin described a "tickle" as two different types of
phenomena
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This type of tickle, called knismesis,
generally does not produce laughter and is sometimes accompanied by an itching sensation
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Such sensations can be pleasurable or
exciting, but are sometimes considered highly unpleasant, particularly in the case of relentless
heavy tickling
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Vellus hairs
Peach fuzz-everywhere, most common
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2
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Hairs that change distribution (upper and lower limbs)
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Terminal hairs
Heavy, dark, sometimes curly (head, eyebrows, eyelashes)
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Curly hair is determined the style of pore it comes out of, a flat pore produces curly hair
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Hair color
• Based on differences in hair structure and pigment
• Genetically determined
• Influenced by hormones/environment
• Black/brown: density of melanin in cortex
• Red: biochemically distinct form of melanin
• Pigment production decreases with age - gray
• GROWTH
• One hair grows for 2-5 years (1/64th inch per day)
• End of growth cycle occurs as hair gets pushed toward surface by new hair in follicle
• 50 hairs lost a day is normal
• Hair loss
• >100 hairs lost/day may indicate problem
• In males, changes in sex hormones causes terminal hairs to become vellus hairs (male
pattern baldness)
• Stress can cause more hair loss
Glandular epithelia- go home and make chart on white board to memorize
Exocrine
-Exo-outside
-Secrete onto a surface through duct
Endocrine
-hormones

Sebaceous glands

• Secretion:
• Waxy, oily – called sebum
• Target:
• Hair follicles - surface of skin
• Mechanism:
• Arrector pili moves contracts, elevates hair, squeezes gland
• Function:
• Provides lubrication, inhibits bacteria
-Shampooing removes naturally oily coating from hair, excessive washing can make hair stiff and brittle

Sebaceous follicles

• Location: integument of face, neck, back, chest, nipples, and male sex organs
• Sebum is naturally bactericidal (can kill bacteria it comes in contact with)
• Follicles/glands can be invaded by bacteria, producing a local inflammation = FOLLICULITIS,
acne can be
• If gland blocked, abscess forms = FURUNCLE (boil), big inflammation response

Sweat glands-aka Sudoriferous glands
• Sweat glands are also called sudoriforous glands
• Types
1
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MEROCRINE SWEAT GLANDS (aka eccrine)

*Know chart that shows location of both kinds of sweat glands on power point*
*Mostly sweat in hands and feet*
Apocrine
• TARGET
• Hair follicles in axillae, nipples, groin
• STRUCTURE
• Coiled tubular glands
• SECRETION
• Viscous, cloudy, sometime odorous
• May also contain pheromones
Merocrine
• TARGET
• Surface of skin
• STRUCTURE
• Coiled, tubular glands
• Far more numerous than apocrine, most predominant on palms/soles
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▪ Mechanical stress can trigger stem cell divisions resulting in calluses
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▪ The inability to completely heal after severe damage may result in a cellular scar tissue
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▪ Provides a route and a place for attachment for circulatory and nervous supply
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▪ Attaches the bone to the connective tissue network of the deep fascia

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