Coelenterata Flashcards
what is the cavity present in the coelenterata called
gastro-vascular cavity
what are the different types of gastro-vascular cavity
- with compartments
2. without compartments
which class of animals contains the gastro-vascular cavity with compartments
anthozoa
what are the members of phylum coelenterata called
cniderians/coelenterates
how do the gastro-vascular cavity of some members have compartments
due to the invagination of the body wall into the gasto-vascular cavity
who coined the term coelenterata
who coined the term cnideria
Leukart
Hyman
symmetry of the members of coelenterata
they are radially symmetrical except sea anemone bi
radially symmetrical
why are they called the cniderians
consist of the cnidoblast cells (stinging cells)
what kind of tentacles are found in hydra and obelia
hydra has hollow tentacles while obelia has solid tentacles (h for h)
what is the universal character of all cniderians
cnidoblast cells
what is the habitat of the cniderians (on the basis of the classes)
they are mostly marine and few fresh water (eg Hydra)
hydrozoa - most marine few fresh water
scyphozoa - marine
anthozoa - marine
name the following
sea fur
sea pen
se fan
obelia
pennantula
gorgonia
which of the following is solitary, colonial and free swimming
aurelia
obelia
hydra
hydra - solitary , sessile
obelia - colonial
aurelia - free swimming
what is the grade of organization of the members of coelenterata
they have tissue level of body organization
how many germ layer do the member of coelenterata have
2 they are diploblastic
what is the name of the body wall
epidermis and gastrodermis/endodermis
what is the middle transparent jelly like material called
mesoglea
what is mesoglea composed of
it is composed of mucopolysaccharide which is secreted by both epidermis and gastrodermis
this layer is non cellular
what is the function of the mesoglea
it provides nutrition to both epidermis and gastrodermis
Q. mesoglea in hydra:
a. non-cellular, can be crossed by interstitial cells
b. non-cellular, cannot be crossed by interstitial cells
it is non-cellular which can be crossed by the interstitial cells, during the time of bud formation the interstitial cells or the totipotent cells move from the gastrodermis to the epidermis
what is delamination
the process of conversion of hollow bastula to the solid gastrula by the proliferation of the bastomere cells
how is the gastrovascular cavity formed
gastrovascular cavity is formed by the splitting of the endodermal cells of gastrula
what are the different types of cells found only in epidermis
S(2)INEG(2) Stinging cells/Cnidoblast cells sensory cells Interstitial cells Nerve ells Epithelio-muscular cells Glandulomuscular cells Germ cells/Sex cell
what are the two cells which are only found in the epidermis
CG
Cnidoblast cells
Germ cells
in hydra the pedal disc is covered by
gland cells
in hydra the tentacles have maximum number of
cnidoblast cell
in hydra the origin of cnidoblast is
ectodermal
what is nematocyst
it is the capsular structure around the nematoblast which stores and secrete hypnotoxin which paralyses the prey
what are the different types of cnidoblast cells
penetrants/stenotels
volvents/desmonemes
holotrichors icorhiza/ streptoline glutinant
atrichous icorhiza/stereoline glutinant
smallest nematocyst
largest nematocyst
largest glutinant
smallest glutinant
desmonemes/ volvents
stenotels/penetrants
streptoline glutinant/holotrichous ichrohiza
stereoline glutinant/atrichous ichorhiza
which is the most complex nematocyst
stenotels/penetrants
what are the different functions carried out by different nematoblast
penetrants/stenotels - secrete hypnotoxin and paralyses the prey
desmonemes/volvnet - coiles the paralysed prey
holotrichous ichorhiza/streptoline glutinant- attaches the prey
atrichous ichorhiza/streoline glutinant - helps in the looping movement (leech like movement)
what is the sensory structure of the nematocyst called
what is the opening of the nematocyst called
what is the contractile thread like structure of the nematocyst called
cnidocil(because of the presence of its own sensory structure it is also called the independent effector of hydra, because the information gathered from the body wall has no use on it)
operculum
lasso
what are the stimuli that stimulates the cnidocil
touch or the chemical glutathione (because of which hydra only feed on water flea i:e. daphnia and cyclopes as they secrete glutathione.
what is the mechanism for the discharge of cnidoblast
it occurs by physical mechanism (hydrostatic pressure)
what happens to the cnidoblast cell after it is discharged
the cnidoblast cell can only be discharged (used) once, after it is used it is sent to the gastrovascular cavity where it is digested
what are the different mode of locomotion in hydra and which is most common, fastest and slowest
somersaulting - fastest
walking - cuttle fish like
looping (leech like)- most common
gliding movement (snail like) - slowest
what are the stimuli that stimulates the cnidocil
touch or the chemical glutathione (because of which hydra only feed on water flea i:e. daphnia and cyclopes as they secrete glutathione.
what is the mechanism for the discharge of cnidoblast
it occurs by physical mechanism (hydrostatic pressure)
what happens to the cnidoblast cell after it is discharged
the cnidoblast cell can only be discharged (used) once, after it is used it is sent to the gastrovascular cavity where it is digested
what are the different mode of locomotion in hydra and which is most common, fastest and slowest
somersaulting - fastest
walking - cuttle fish like
looping (leech like)- most common slowest
what is the main function of the interstital cells
generation of further type of cell like the cnidoblast cells, germ cells or sex cells and give coelenterata the power of regeneration
what is the mode of reproduction in hydra
hydra reproduce asexually by the formation of internal bud of gemma in favorable condition and sexually by gamete formation in unfavorable condition
how does the body and tentacles regenerate
the body of hydra regenerate by morphollaxis while the tentacles regenerate by epimorphosis
how is the distribution of testes and ovary in bisexual hydra
there are many testis and single ovary
what is the origin of the gonads
gonads are ectodermal in origin as most of the interstitial cells are ectoderm ally situated
what is the location of testis and ovary in hydra
testis are located towards the distal end while ovary are located towards the proximal end/aboral end
how does the body and tentacles regenerate
the body of hydra regenerate by morphollaxis while the tentacles regenerate by epimorphosis
what kind of cleavage is found in hydra
holoblastic cleavage
what kind of development in found in hydra
direct development(development without the larval stage)
explain the epithelio-muscular cell
- it is tall and uninucleated with epithelial part and muscular part
- the epithelial part has the covering of cuticle on it for protection (located towards the free end)
- just below the cuticle are the mucus body and the cuticle forming granules
- the muscular part is towards the narrower end located towards the mesoglea
what is planula
this is the common larva of all the cniderians specially jellyfish, obelia, sea anemone and sea coral
what is the function of myonemes of the epitheliomuscular cells
they are responsible for the shortening and bending of the body
why does hydra shows movement
hydra shows movement for nutrition and suitable environment but not for locomotion
explain the epithelio-muscular cell
- it is tall and uninucleated with epithelial part and muscular part
- the epithelial part has the covering of cuticle on it for protection
- just below the cuticle are the mucus body and the cuticle forming granules
- the muscular part is towards the narrower end located towards the mesoglea
what do the muscular part of the epithelio-mucular cell contains
it has myonemes or myofibrils made up of actin and myosin
what is the function of myonemes of the epitheliomuscular cells
they are responsible for the shortening and bending of the body
what is the structure of the glandulo-muscular cell and where is it maximum in number
they are the modification of the epithelio-muscular cells located maximum on the pedal disc
what is the function of the glandulo-muscular cell
- gliding movement (by pseudopodia formation and lubricating the surface)
- attachment to the substratum
- sometimes create water bubble for the purpose of floating
