Ecdysozoa protostomes {annelid}| are higher worms.
skin
Epidermis secretes mucus and cuticle, to prevent water loss.
movement
Circular and longitudinal muscles cause movement by stretching and contracting.
digestion
Annelids have schizocoelom. Annelids have mouth, pharynx, esophagus, crop, gizzard, and straight intestine.
blood
The two main blood vessels connect by pairs of muscular tubes acting like hearts. Vessels have capillaries.
nervous system
Head has stimulating ganglion and inhibiting ganglion. Segments have one small ganglion each. Reflex arcs run from sense cells to muscle sets. Neurons have few dendrites, no myelination, few Schwann cells, no oligodendroglia, no astrocytes, no microglia, no nerve tracts, no inhibitory surrounds in receptor fields, no feedback circuits in receptor fields, and no amacrine cells in receptor fields. Neurons have basic neurotransmitters, ion channels, excitability, synaptic potentials, pacemakers, and rhythmic voltage patterns, with frequency twice as high as in vertebrates.
senses
Annelids can have eyes and antenna. Membranes cover visual pits to protect photoreceptor cells.
pigment
Earthworms have pigmented skin cells.
pain
Worms feel no pain.
Biological Sciences>Zoology>Kinds>Annelid
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Date Modified: 2022.0224