notes for periodic classification of elements
Saturday 28 June 2014
Friday 27 June 2014
EARTH
WORM JIPMER
lampito
mauritii is 8-21cm long and 3-4 mmwide
clitellum
is present in 14-17 segments
dorsal
pores commence from the 10th segment.through these segments the
coelom communicates to exterior
three
pairs of spermathecal openings are situated ventrolaterally b/w 6, 7
7,8 8,9
oviducal
openings are pair on the ventral surfaces of the 14th segment
spermiducal
opening 18th segment
nephridiopores
in the14th segment
cuticle
is secreted by epidermis
epidermis
contain gland cells and receptor cells
muscles
are of 2 types outer circular & inner longitudinal
when
the circular muscles of the body contract body gets thin and
elongates thereafter which results in forward movement
when
the longitudinal muscles contract body becomes thick and shrinks
mouth
occupies segment 1,2
pharynx
occupies segment 3,4 and is surrounded by the pharyngeal glands
oesophagus
lies in 5th segment
gizzard
lies in 6th segment
intestine
starts from 7th segment and upto 14segments it is narrow and the
remaining part is sacculated
the
dorsal wall of intestine is folded into th cavity as the typlosole
the
dorsal longitudinal vessel runs above alimentary canal
while
the ventral longitudinal vessel runs below the alimentary canal
dorsal
b.v. has valves and is contractile in nature wherein blood flows
forwards
the
opposite is the case in ventral b.v.
in
the anterior part of the body the dorsal vessel is connected with the
ventral vessel by 8 commisural vessels or the lateral hearts lying in
6-13 segments. these vessels rum on the lateral sides of the body
wall and
supply
blood from dorsal b.v. to ventral b.v.
the
dorsal vessel recieves blood from various organs and ventral vessel
supplies blood to various organs
excretory
system
excretion in earthworm is through nephridia
a
typical nephridia has an internal funnel like opening called
nephrostome . it is fully ciliated.
nephridia
terminates in nephridiopore
there
are three types of nephridia found in megascolex
viz
meganephridia
, micronephridia , pharyngeal nephridia
besides
nephridia there are specialised cells on the wall of intestine called
chloragogen cells
they
help nephridia in collection of excretory products
the
brain in l.mauritii is formed of sopra pharyngeal ganglia and is
bilobed , situated in the 3rd segment the ganglia found below the
pharynx is sub pharyngeal ganglion ,both are connected through circum
pharyngeal connectives they are situated laterally to pharynx
this
leads in the formation of a nerve
ring
the double solid ventral nerve cord runs backward from the sub
pharyngeal ganglion
in
l.mauritii protandry is seen
male
reproductive
system
two
pairs of testes and apair of vas deferense constitute male
reproductive system
testes
are found in 11-10 segmaents seminal vesicles are found besides
testicular segments as lateral outgrowths
seminnal
funnels are also present which are called as ciliary rosettes found
beside testes
these
ciliated funnels are connectec through vas deferens , the 2 vas
differens run upto 18th segment where they open to the exterior
through male genital opening
male
genital apertures contain pineal setae , prostate glands in 18 &
19 segments prostate opens to the exterior through vas deferens...
the
secretion of prostate help to arrange the sperms into bundles called
spermatophores
female
reproductive system
a
pair of ovaries are seen in 13th segment. there are a pair of
oviducts they open internally into the 13th segment and externally on
the ventral surface of 14th segment
three
pairs of spermathecae are present in 7,8,9 segments
after
copulation the glandular cells of the clitellum secrete a thick fluid
which hardens into a girdle surrounding the clitellum
which
later seperates out from the body in the form of a cocoon
fertilization
and development of the eggs into worms takes place within the cocoon
young
worms come out of the cocoon after complete development
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