What is the function of Rhopalia?
Rhopalia (singular rhopalium) are the most obvious sensory structures of scyphozoan jellyfish. They include specialized structures for sensing light (eyespots) and movement or direction with respect to gravity (statoliths).
Where are the Rhopalia located?
Rhopalia are club-shaped bodies located around the bell margin in medusae of scyphozoans and cubozoans, with the number typically in multiples of four (Fig. 1c–g; Hyman 1940).
What is meant by rhopalium?
Rhopalia (singular: rhopalium) are small sensory structures of Scyphozoa (typical jellyfish) and Cubozoa (box jellies). Specialized structures to sense light (ocelli) and perceive gravity (statoliths) are usually present. They also control the pace of swimming-muscle contraction.
Are Rhopalia eyes?
Cubozoans have the most intricate visual apparatus within Cnidaria. It comprises four identical sensory structures, the rhopalia, each of which holds six eyes of four morphological types. Two of these eyes are camera-type eyes that are, in many ways, similar to the vertebrate eye.
What is mesoglea made of?
ectoderm of coelenterates is the mesoglea, a gelatinous mass that contains connective fibres of collagen and usually some cells. Both layers contain muscle fibres and a two-dimensional web of nerve cells at the base; the endoderm surrounds a central cavity, which ranges from simple to complex in shape and serves…
What is the anatomy of a jellyfish?
They are composed of three layers: an outer layer, called the epidermis; a middle layer made of a thick, elastic, jelly-like substance called mesoglea; and an inner layer, called the gastrodermis. An elementary nervous system, or nerve net, allows jellyfish to smell, detect light, and respond to other stimuli.
What is the meaning of nematocysts?
: one of the stinging capsular organelles of the tentacle of a cnidarian (such as a box jellyfish or sea anemone) that contains a coiled, hollow, usually barbed, venomous thread which is discharged especially for catching prey and defending against enemies Each nematocyst contains a spiral-coiled thread tipped with a …
What is Mesoglea made of?
What is the function of Cnidocytes?
Cnidocytes (‘stinging cells’) are specialized cells that define the phylum Cnidaria (sea anemones, jellyfish, corals and hydras). They contain an “explosive” organelle called cnidocyst that acts as a 600 million-years-old microscopic injection system and is important for prey capture and anti-predator defense.
What is the importance of mesoglea?
The mesoglea serves as an internal skeleton, supporting the body. Its elastic properties help restore the shape after it is deformed by the contraction of muscles.
What is the meaning Nematocyst?
Nematocyst, minute, elongated, or spherical capsule produced exclusively by members of the phylum Cnidaria (e.g., jellyfish, corals, sea anemones). Several such capsules occur on the body surface.
How many hearts does a jellyfish have?
They don’t have a heart, lungs or a brain either! So how does a jellyfish live without these vital organs? Their skin is so thin that they can absorb oxygen right through it, so they don’t need lungs. They don’t have any blood so they don’t need a heart to pump it.
Where are the rhopalia located in a Scyphozoa?
Rhopalia (singular: rhopalium) are small sensory structures of Scyphozoa (typical jellyfish) and Cubozoa (box jellies). In Aurelia they lie in marginal indententions around the bell and are flanked by rhopalial lappets. Specialized structures to sense light (ocelli) and perceive gravity (statoliths) are usually present.
What kind of structures are found in the rhopalium?
Rhopalium. Specialized structures to sense light ( ocelli) and perceive gravity ( statoliths) are usually present. They also control the pace of swimming-muscle contraction. Cubozoan ocelli are the most complex of Cnidarians, and resemble the image-forming eyes of squids, octopuses and vertebrates .
Where are the rhopalial lappets located in the Aurelia?
Rhopalium. In Aurelia they lie in marginal indententions around the bell and are flanked by rhopalial lappets. Specialized structures to sense light ( ocelli) and perceive gravity ( statoliths) are usually present. They also control the pace of swimming-muscle contraction.
What is the role of the liver in hematology?
The liver is the storage location for fat-soluble vitamins and handles cholesterol homeostasis. It stores iron and copper. It plays a role in hematology with clotting factor and protein synthesis. The liver plays a role in heme breakdown into unconjugated bilirubin and conjugates it.