Protection and Support

Protection

  • integument: external covering

  • functions?

    • protection

    • temperature regulation

    • excretion

    • vitamin formation

    • reception of stimuli

    • locomotion

    • respiration

    • support

Protozoa

  • plasma membrane (Amoeba)

    • gas exchange VIA diffusion

    • nutrient uptake

  • pellicle (Paramecium)

    • thick protein coat

Multi-Cellular Inverts

  • e.g. Cnidarians, Molluscs, Annelids

  • single layer of columnar epithelial cells

    • “epidermis”

  • rests on basement membrane

    • non-cellular, fibril layer

  • some glandular cells

Flatworms

  • “tegument”

    • helps with internal camouflage

Anthozoans 

  • stony exoskeleton

    • mucous glands in ectoderm secrete CaCO3

    • protecting their soft interior

Arthropods

  • cuticle

    • chitin and protein plates

    • gets shed (“ecdysis”)

      • allows for more growth

      • shed parasites

      • shed injuries

Cartilaginous Fish

  • bony dermis

    • “denticles” 

      • placoid scales

      • contain blood vessels and nerves

        • similar to teeth

Bony Fish

  • scales

    • ctenoid, cycloid, and ganoid

    • made of dermal bone

    • grow continuously

    • can be used to age fish

Amphibians

  • stratified epidermis

    • numerous glands

      • protect from disease

      • support terrestrial and water lifestyle

Reptiles

  • keratinized scales

    • keratinization

    • stratum corneum

      • terrestrial adaptation

    • no glands = dry

    • needs to be shed

Birds

  • derived from stratum corneum

  • dermal smooth muscle controls position of feathers

  • fat deposits in the hypodermis help insulate

    • importance ?

      • allows flight

Mammals

  • skin

    • grows with animal

  • three layers:

    • epidermis

      • stratified, squamous epithelium

        • controls permeability

    • dermis

      • connective

        • collagenous, reticular (net-like layer), and elastic

    • hypodermis

      • loose connective tissue and adipose tissue

      • nerve ending

  • variety of glands

    • sweat glands

      • thermoregulation

    • sebaceous glands (oil)

      • permeability barrier

      • skin conditioner

  • vitamin D production

    • inner layers of epidermis

  • hair 

    • develops from epidermis

    • connected to arrector pili muscles

      • provide insulation