1. Comparative Anatomy Biology Dept. Misericordia Univ. Dr. Tony Serino
Integument
Comparative Anatomy
Biology Dept.
Misericordia Univ.
Dr. Tony Serino

2. Integumentary System: Skin
Functions:
Protection
Germ and water proof barrier, abrasion resistant, defense
Sensory
Organ in first contact with external environment
Homeostasis
Thermoregulation (excretory), Ca++ balance, respiration in some species
Communication
Muscle attachment
Secretes phermones –for communicating

3. Layers of the Mammalian Skin
Epidermis
Outermost layer, composed of keratinocytes
Dermis
Thickest layer, composed of many connective tissues and is the site for many glands and other epidermal derivatives
Subcutaneous layer (Hypodermis)
Attaches skin to underlying structures

4. Epidermis
Composed of 4-5 layers of keratinocytes which is formed into a stratified squamous epithelium
Main gene product is keratin, a water insoluble protein
Some cells from the dermis invade and reside in the epidermis’ deepest layers including Merkel cells, Langerhans cells, and melanocytes
Epidermis

6. Epidermal Layers
(basale)

7. Dermis
Composed of a mixture of CT, including dense irregular, loose areolar, elastic, and adipose tissues
Divided into 2 regions:
Papillary layer: region of dermal papillae
Reticular layer: thickest layer of skin, provides strength, elasticity and space for glands, hair follicles, etc.

8. Dermal Papillae (friction ridges): arranged into regular patterns in palms and soles

9. Burns
1st
2nd
3rd

10. Skin Cancers
Squamous cell carcinoma
Basal cell carcinoma
Melanoma

11. Papillary Region
Reticular Region
Hypodermis

20. Epidermal Derivatives
Structures which grow from the epidermis but reside mostly in the dermis
Scales (epidermal scales fond only in amniotes)
Nails, claws, hoofs
Hair and Feathers
Horns and antlers
Glands of skin

21. Dermal scales –found in fish
Epidermal scales

23. Hair
Hair shaft
Sebaceous gland
Hair root
Hair Bulb
Hair papilla

24. Hair Follicle X.S.

26. Pterylae

27. Contour
Filoplume
Down

29. Horns and Antlers

31. Nail
Nail Fold
Nail Matrix
Nail Bed

32. Tori (torus, sl.)

33. Baleen
Combs and Beaks

34. Exocrine Glands Secrete product into duct or external surface
Only single cell gland in human is the Goblet cell
All other glands can be classified by structure or type of secretion method used

36. Functional Classification: method of secretion
Merocrine secretion
Secretes by exocytosis using vesicles
Apocrine secretion
Secretes by storing product in cell’s tip (apex), then breaking of entire tip
Holocrine secretion
The entire cell is secreted with its product

37. Merocrine Secretion

38. Apocrine Secretion

39. Holocrine Secretion

40. Structural Classification
Grouped by duct structure
Simple –a single duct leads from secretory unit to surface
Compound –duct branches to connect surface to secretory unit
Grouped by shape of secretory unit
Tubular –tube shaped
Alveolar (Acinar) –flask-like sac

43. Epidermal Glands of Mammals
Sebaceous glands –secretes sebum (an oil) used to maintain skin and hair moisture
Ceruminous glands –secretes cerumen (ear wax), used to keep foreign objects out of ear
Sudoriferous (sweat) glands –secrete sweat (water with some salts), used in heat regulation and in phermone secretion: two types: Apocrine and Eccrine (Merocrine)
Mammary Glands –secrete milk

44. Sweat Glands

46. Milk Line

47. Breast

48. Breast Cancer
Normal
Tumor

49. Mammary gland

51. Epidermal glands in other animals
Skin Mucous Glands –fish, amphibians
Granular (Serous) glands –found in fish, amphibians and some reptiles; can be poisonous, usually secrete pheromones
Photophores –light emitting glands in some fish (flashlight fish)
Uropygial glands –preening oil gland at base of tail in many birds

52. Photophores
Uropygial gland

53. Dermal Pigment (chromatophores)
Melanophores (melanocytes) –secrete melanin
Xanthophores –contain yellow pigment
Erythrophores –contain red pigment
Iridiophores –contain prismatic substance which refracts light
Physiological Color change –due to dispersement or aggregation of pigment granules in the chromatophore
Morphological Color change –due to long term exposure to light and changing season; cells incapable of dispersing or aggregating pigment

54. Melanocytes: produce melanin

55. Dermal bone derivatives

56. Cosmoid Scales only found on extinct Crossopterygians, non-overlapping scales like ganoid