Exercise 14: Animal Integuments andDerivatives

• Integument - outermost covering of the animal which serves many functions such as protection, sensation, and homeostasis
• Integumentary derivatives - most animals possess these external structures that originate from the integument
• Hardened integumentary derivatives form an exoskeleton that functions for the protection of internal structures, and in some animals, attachment of muscles.
• Integumentary derivatives include long-lasting secretions and deposits of what?

  Epithelium
• Integument consists of an epithelial layer called what?

  Epidermis
• In invertebrates, integument derivatives are largely secretions that are laid over epithelium. These include the shell of snails and bivalves, which are mostly calcareous
• The cuticle of the earthworm is collagenous, while its hair-like setae are chitinous in nature.
• The chitinous cuticle of arthropods is segmented into what?


  plates
• The exposed part of the snail which is covered by typical epidermis is called what?

  Foot
• The visceral mass found under the shell is covered by what?

  Mantle
• In an Ascaris lumbricoides, the outermost thick non-cellular layer is what?

  Cuticle
• Inner to the cuticle of the Ascaris lumbricoides is what?

  Epidermis
• What is found immediately beneath the epidermis of the Ascaris lumbricoides?

  longitudinal muscle
• What group of organisms posses a complex integument such as the skin?

  All vertebrates, echinoderms
• What are the outer and inner regions of the skin respectively?

  Epidermis, Dermis
• Stratum corneum - outermost layer of the epidermis that are dead and constantly being shed off. These are often one layer thick and is made up of squamous cells.
• Stratum germinativum - innermost layer of the epidermis which consists of a monolayer of columnar cells that lies over the dermis.
• As columnar cells divide and give rise to new cells that are pushed to the outer layer, when they migrate up, they become more flattened as they differentiate into what cells of the stratum corneum?

  Keratinized cells
• Stratum laxum - Found in the dermis layer of loose connective tissue
• What does the stratum laxum contain within the loose connective tissue?

  cutaneous glands, chromatophores
• Chromatophores - cells that contain pigment granules that are darkly stained and mostly lying beneath the epidermis
• Cutaneous glands - formed by the infolding of the stratum germinativum into the dermis
• Stratum compactum - deeper layer of the dermis which is made of dense, irregular connective tissue in alternating horizontal and vertical strands
• Subcutaneous loose connective tissue - below the stratum compactum which connects the skin with the underlying muscle
• Vertebrates posses derivatives of what?

  Dermis or epidermis
• Derivatives of the dermis include the bony scales of the fish, and antlers (false horns) of the deer.
• Epidermal derivatives include horny scales of reptiles, birds, and mammals; hairs or fur and feathers.
• What are epidermal derivatives found in the digits?

  Nails, claws, hooves
• In certain vertebrates, both dermal and epidermal derivatives may be present in the same exoskeleton such as the turtle shell wherein it's composed of the dorsal caraspace and the ventral plastron
• The outer, darker layers of the caraspace and plastron of the turtle shell originate from what and are termed what?

  Origin: Epidermis Term: scutes
• The inner, lighter layers of the caraspace and plastron originate from what and are termed what?

  Origin: Dermis

  Term: Plates
• Outline the general morphology of a snail.

  A) Shell

  B) Mantle

  
• Outline the integument of Ascaris lumbricoides

  A) Cuticle

  B) Epidermis

  
• Outline the morphoanatomy of the frog skin.

  A) Epidermis

  B) Dermis

  C) Cutaneous gland

  D) Stratum corneum

  E) Stratum germinativum

  F) Stratum laxum

  G) Chromatophores

  H) Stratum compactum

  I) Subcutaneous loose connective tissue

  
• Differentiate between true and false horns.

  A) Epidermis

  B) Dermal

  C) Unbranched

  D) Branched

  E) Hollow

  F) Solid

  G) Permanent

  H) Seasonal

  I) Male and female

  J) Male