Biology Questions and Answers
the tissues to be irrigated. In closed
circulatory systemswithin blood vessels and through the blood circulates only
heart.
- What is the type of
circulatory system present in
annelids?
In beings of the phylum circulatory system is closed, i.e., bloodAnnelida the (^)
circulation takes placspecialized vessels. e only within
- Is there a respiratory
pigment in the annelid blood?
The blood in beings of the phylum
Annelida contains thpigment hemoglobin e respiratory(the same found in (^)
chordates) and other pigments too.
- How can the presence,
localization and function of
muscular tissue in beings of
the phylum Annelida be
explained?
In these beings there are a longitudimuscular layer under the epidermis annald, (^)
internally juxtaposed and perpendicular
to it, amuscularnother circular layer. The circular (radial to t musclehe axis)
layer has the function of elongating the
body while the longitudinal shBy alternating actions both promoteortens it.
movement.
- How can the excretory
system of annelids be
described?
In each segment (mbeing a pair of complete eetamere) xcretoryof the
structures calleThe metanephridium d metanhas an ephridium exists.extremity,
the nephrostoma, which collects
residuals frthem and causinom the coelom, g reabsorption alonfiltering (^) g its
extension (similar to human nephron
tubules). The material to bgoes out through a pore, thee excreted
nephridiopore, which opsurface. ens in the body
- How is the nervous system
characterized in beings of the
phylum Annelida? How can
one compare cephalization in
annelids to cephalization in
nematodes and
platyhelminthes?
Annelids have a nervous system maof two ventral chords and one relativelyde (^)
big nervous cell concanterior portion resembling a primitiveentration in its (^)
brain.
Nematoconnectedes have an anterior nd to two neural chords, aeural ring
ventral anplanarias (platyhelmid a dorsal onnthes) the, while inere are (^)
only two small anterior “cerebral”
ganglia from which neural chords split.Cephalization in annelids thus is more
outstanding than in nematodes or in
flatworms.
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