mammals part v vertebrate zoology (vz lecture33 spring 2012 althoff - reference pjh chapter 21)...
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DERMIS FDVM p60, Fig. 5.2TRANSCRIPT
Mammals – Part V
VERTEBRATE ZOOLOGY (VZ Lecture33 – Spring 2012 Althoff - reference PJH Chapter 21)
Bill Horn
Skin & Glands
Unique Mammalian Characteristics Associated
with the Skin
• HAIR• SWEAT GLANDS• SEBACEOUS GLANDS• SCENT GLANDS• MAMMARY GLANDS
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FDVM p60, Fig. 5.2
Hair• Has its origin in the dermal layer
(dermis)• Consists of dead epidermal cells
strengthened by keratin (a tough, horny tissue made of protein)
• Functions: a) ___________ b) sensory c) camouflage d) defense e) aggression
1
Cells “invaginate”,In the epidermis
= epidermis= dermal = subcutaneous
HAIR DEVELOPMENT
2
“Hair” projectsdownward aswell as grows up
3
Rooted insubcutaneouslayer
Mescenchmalaggregation Mescenchmal
aggregation
Pigmentcells Hair
cone
Papilla
Hairbulb
Sweat Glands
• Has its origin in the dermal layer (dermis)• Functions: ______________
_______________• Two types: a) eccrine--separate duct at
surface; usually well distributed over bodyb) apocrine--duct at exit point (pore)
of hair; armpits, anogenital region, naval, nipples, & ears; in ears: modified to produce wax
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FDVM p60, Fig. 5.2
Eccrine sweat pore
ApocrineSweat duct
Pore
Sweating part ofapocrine sweat gland Secreting part of
eccrine sweat gland
Sweat Glands…con’t• Distribution over body surface varies
a) _____________--all over bodyb) _____________--pads of feetc) _____________--feet and/or venter
d) ____________________ --do not have any e) ____________________ --do not have any
Sebaceous Glands• Associated with _________________• Produce and secrete oils a) positioned by erector
pili muscles b) muscle moves, forces oil aroundshaft of hair
• Functions: a) ____________________ b) ______________________
• Lanolin produced by sheep unique• Hartner’s gland: lub for eyes & nictitating membrane
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FDVM p60, Fig. 5.2
Sebaceous gland
Scent (musk) Glands
• Either modified sweat glands or modified sebaceous glands
• Functions: a) ______________b) ______________ c) ______________ d) ______________
• Distribution varies (chin-to-tail): a) skunk: anal region b) wolves & coyotes: top of tail c) ungulates: pre-orbital area
Mammary Glands
• Also known as ____________• Elaborate , elongated duct system with
hollow sacs at end: a) alveolus--individual sac b) lobules of andular tissue--group of alveoli
• Function: milk production
clavicle
intercostalmuscle
LACTIFEROUS DUCTLACTIFEROUS SINUS
AREOLA
NIPPLE
pleura
pleuralcavity
pectoralismajor
rib
LOBULES of ANDULAR TISSUE
ADIPOSE TISSUE
MAMMARYTISSUEshowingindividual
__________
LOBULEOF
ALVEOLI
LOBULEOF
ALVEOLI
Milk __________ “_________”
Mammary Glands…con’t
• Always on ventral sidea) primates: 2 thoracic mammaeb) perissodactyls: 2 inguinal mammaec) most rodents: 5 pairs on belly
(chest to groin)d) NA opossum: 13 (12 in circle, 1 in
center of circle)e) whales: mammary grooves
Milk Production• ________ is hormone that stimulates milk
production• ________ is hormone that stimulates milk letdown• Milk content varies in protein & fat content a)
__________________b) __________________c) ____________ (in kangaroos)