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Biological Rhythms Skin: Hair & Glands

Mammalogy (Fall 2013 Althoff - reference FDVM Chapters 6 & 8). LEC 07. Biological Rhythms Skin: Hair & Glands. Biological Rhythms. _______ rhythms --a period of 24 hours _________ rhythms--a period of about 1 year _________ rhythms--anything less than 24 hours. Circadian Rhythms.

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Biological Rhythms Skin: Hair & Glands

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  1. Mammalogy (Fall 2013 Althoff - reference FDVM Chapters 6 & 8) LEC 07 Biological Rhythms Skin: Hair & Glands

  2. Biological Rhythms • _______rhythms--a period of 24 hours • _________ rhythms--a period of about 1 year • _________ rhythms--anything less than 24 hours

  3. Circadian Rhythms • __________ patterns--active mostly during the daylight hours • ___________--active peaks during darkness, rests during daylight • __________ activity--dawn & dusk hours are peak activity periods

  4. Circadian Rhythms: Activity Patterns • Influenced by a) __________ pressure b) peak of ________ availability c) ___________ status 1) mating status 2) most mammals give birth during “inactive” period

  5. Activity Patterns…con’t • DAYTIME Advantage: Disadvantage:

  6. Activity Patterns…con’t • NIGHTTIME Advantage: higher ________ enhances olfactory communication reduced ________ stress reduced __________________Disadvantage: vision (color) __________

  7. Circannual • Influences _________________ CYCLE • Influences _________________ PATTERN • Primary cue is probably _______________ by influencing hormone changes which alter: a) physiology b) morphology c) behavior

  8. Photoperiod influence on... • ____________--increased levels of reproduction hormones, influences level of “reproductive” readiness • ____________--change in pelage, enlarged (and scrotal) testes, antler development • ____________--increased aggression, maternal-type responses (nest building, etc.)

  9. Other influences... • ______________: beach mouse uses lower temps as cue to breed • ______________: montane vole reproduction triggered by presence of 6-MBOA (6-methoxybenzoaxazolinone) in fresh plant shoots. Influences number and size of litters (p152, Table 8.1)

  10. 6-MBOA affects reproduction effort (Microtus montanus) Table 8.1 (p153)

  11. Ultradian • ____________: some show 6 to 12 evenly spaced short activity bouts per 24-hour day • Rheus macaques: observed only during daylight (active) period…with bouts lasting 40-45 minutes. • In general…still ________ understood, including their significance to survival.

  12. Movements in meters Activity rhythm of female meadow vole (Microtus pennsyvlanicus) Fig. 8.10 (p154)

  13. Hey...HAIR & GLANDS! Skin: Hair & GlandsReference FDVM Chapter 6

  14. ________ Mammalian Characteristics Associated with the Skin • HAIR • SWEAT GLANDS • SEBACEOUS GLANDS • SCENT GLANDS • MAMMARY GLANDS

  15. FDVM p98, Fig. 6.2 DERMIS

  16. 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) insulation b) sensory c) camouflage d) defense e) aggression

  17. = epidermis = dermal = subcutaneous 1 2 3 Cells “invaginate”, In the epidermis “Hair” projects downward as well as grows up Rooted in subcutaneous layer HAIR DEVELOPMENT Pigment cells Mescenchmal aggregation Hair cone Mescenchmal aggregation Hair bulb Papilla

  18. Sweat Glands • Has its origin in the dermal layer (dermis) • Functions: __________________________________ • Two types: a) eccrine--separate duct at surface; usually well distributed over body b) apocrine--duct at exit point (pore) of hair; armpits, anogenital region, naval, nipples, & ears (in primates); in ears: modified to produce wax

  19. FDVM p98, Fig. 6.2 Eccrine sweat pore DERMIS Apocrine Sweat duct Sweating part of apocrine sweat gland Secreting part of eccrine sweat gland

  20. Sweat Glands…con’t • Distribution over body surface varies—usually where there is less hair a) __________--all over body b) __________--pads of feet c) __________--feet and/or venter d) ______________________ -- do not have any e) ________ on head only f) ______________________________ _______ do not have any

  21. Sebaceous Glands • Associated with ________________ • Produce and secrete oils a) positioned by erector pili muscles b) muscle moves, forces oil around shaft of hair • Functions: a) ________________ b) ________________ • Lanolin produced by sheep unique • Hartner’s gland: lub for eyes & nictitating membrane

  22. FDVM p60, Fig. 5.2 DERMIS Sebaceous gland

  23. Scent (musk) Glands • Either modified ______ glands or modified ____________ glands • Functions: a) ________ b) ______________ c) _______________ d) _______________ • Distribution varies (chin-to-tail): a) skunk: ____________ b) wolves & coyotes: __________ c) ungulates: _____________

  24. 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: _________________

  25. first rib skin cut pectoralis major muscle suspensory ligament adipose tissue lobe areola nipple opening of lactiferous duct pleural cavity lactiferous sinus lactiferous duct _________________ __________________

  26. EUTHERIAN (placentals) human UNGULATE MONOTREME Alveoli • nipples • teats • No nipples • No teats • Milk oozes out • onto skin

  27. MAMMARY TISSUE showing individual _________ LOBULE OF ALVEOLI LOBULE OF ALVEOLI

  28. Mammary Glands…con’t • Always on ventral side a) primates: 2 thoracic mammae b) perissodactyls: 2 inguinal mammae c) 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

  29. Milk Production • __________ is hormone that stimulates milk production • __________ is hormone that stimulates milk letdown • Milk content varies in protein & fat content a) b) c)

  30. Bottlenose Dolphin • Found in warm temperate and tropical oceans and seas worldwide • 150 – 200 kg (330-440 lbs.) • Gestation period just 12 months, then nurses young for 12-18 months in wild, longer in captivity • Diet includes squid, shrimp, eels, and a wide variety of fishes (carnivorous)

  31. _________ in milk fat and milk water over the course of lactation in bottlenose dolphin Milk fat Dolphin K Milk water Milk Constituent % Dolphin P West et al. 2007 Journal of Zoology 273:148-160 (Fig. 1) Month of Lactation

  32. ________ in milk protein and milk sugar over the course of lactation in bottlenose dolphin Dolphin K Milk protein Milk sugar Milk Constituent % Dolphin P West et al. 2007 Journal of Zoology 273:148-160 (Fig. 2) Month of Lactation

  33. Eastern barred bandicoot • Native to Australia (Victoria) & Tasmania • Medium-sized omnivorous marsupial (~1 kg) • Gestation period just 12 days, then nursed for ~55 days before weaned

  34. _________ in milk content over weeks 3-9 of lactation in eastern barred bandicoot Lipids = fat Total solids Protein Carbohydrate Ikonomopoulou et al. 2005 Australian J. of Zoology 53:59-65 (Fig. 1)

  35. MILK CONTENT (%) by Species(selected from FDVM Table 6.1, p103) WaterProteinFatSugarAsh Kangaroo 73.5 9.7 8.1 3.1 1.5 Human 88.0 1.2 3.8 7.0 0.2 Rabbit 71.3 12.3 13.1 1.9 2.3 Rat 72.9 9.2 12.6 3.3 1.4 Harp seal 43.8 11.9 42.8 0.0 0.9 B-n dolphin 44.9 10.6 34.9 0.9 0.5 W.t. deer 65.9 10.4 19.7 2.6 1.4 Giraffe 77.1 5.8 12.5 3.4 0.9 Note: ASH = not water & not organic

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