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endocrine versus neural integration a question that surely comes across your mind is what is the need for two types of integrative mechanisms the
endocrine system the nervous system brings about integration and co-ordination of several activities of the animal the afferent stimuli from several
photoreceptorsphotoreceptors are concerned in absorption of light by photosensitive pigments the chemical change involved produces the impulse
chemoreceptorsthese are receptors included in perception of chemical stimuli you will see that there are three kinds of chemoreceptors among
stretch receptorsstretch receptors able of perception of muscle tension or stretch are distributed in the connective tissue related with muscles of
giant nerve fibres we now know that giant nerve fibres take place in the central nervous system of many polychaetes oligochaetes insects cephalopod
information processing in sensory neuronyou have previously seen that the sensory neuron transmits the information it receives as an action potential
properties of receptorsthe receptors collect information concerning the change in the environment such as temperature illumination etc in lower
motor control in annelids and arthropodsin annelids and arthropods generally individual metameric ganglia of the ventral nerve cord are capable of
advanced nervous systems - general trend in evolution in higher groups of animals you will observe clear trends towards centralisation of the nervous
nervous system of echinodermsprevious to studying the nervous system of echinoderms you have to bear in mind the peculiar organization of these
primitive nervous system - nerve neta nervous system creates its appearance for the first time in the phylogeny among cnidaria in this group the
organisation of nervous system nervous systems are composed of nerve cells or neurons and glial cells in the latter half of the 19th century it was
nerve cell - the basic unit the basic unit of the nervous system is the nerve cell or neuron a neuron is to the nervous system what a brick is to the
nervous system and sense organsthe non-chordates also perform a variety of activities such as feeding digestion locomotion etc for this aim they have
closed type of circulatory systemssome non-chordates like cephalopods octopuses squids earthworms polychactes and all vertebrates have a closed
circulatory systemcoelenterates and platyhelminths nutrients in sponges respiratory gases and waste materials can easily diffuse through the
open and closed type of circulatory systems there are two categories of circulatory system found in higher metazoans in one type the original
chlorocruorins - respiratory pigmentsthese types of respiratory pigments are found in four polychaete families sabellidae serpulidae ampharetidae and
hemerythrins - respiratory pigmentsthe hemerythrins are rather rare they take place in some animals belonging to the minor phyla like the sipunculid
haemocyanin - respiratory pigmentsthis pigment is found in several arthropods and molluscs haemocyanins do not consist of haee groups the metal they
hemoglobins - process of respiration hemoglobins are the very well known of all respiratory pigments the basic molecular unit of hemoglobin contains
process of respiration respiratory and circulator system gaseous exchange that is intake of oxygen and output of carbon dioxide takes place at the
gaseous exchangegaseous exchange is take place on by both mantle and the gills the gills of most bivalves are highly changed for filter feeding they
gills - respiratory organsgills are the specialised respiratory organs of several aquatic animals they are found in mollusis and as well in many