Organ system of Hirudinaria granulosa.
The digestive system of leech consists of Alimentary canal, Food,feeding, and digestion,Alimentary canal of the leech is a complete, straight tube of varying diameter, extending from mouth to anus. It is differentiated into buccal cavity,pharynx, oesophagus,crop,stomach, intestine and rectum.Hirudinaria has a sanguivorous habit,sucking the blood of cattle and other domestic animals which visit water harbouring them.A leech can suck, at a single meal, several times its own weight of blood, which is enough for the animal for several months or even year.
Summary
The digestive system of leech consists of Alimentary canal, Food,feeding, and digestion,Alimentary canal of the leech is a complete, straight tube of varying diameter, extending from mouth to anus. It is differentiated into buccal cavity,pharynx, oesophagus,crop,stomach, intestine and rectum.Hirudinaria has a sanguivorous habit,sucking the blood of cattle and other domestic animals which visit water harbouring them.A leech can suck, at a single meal, several times its own weight of blood, which is enough for the animal for several months or even year.
Things to Remember
- Digestive system of Hirudinaria
- Alimentary canal,food feeding digestion of Hirudinaria.
- Histology of alimentary canal.
- The respiratory system of Hirudinaria.
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Q1:
What is measles?
Type: Very_short Difficulty: Easy
Q2:
How measles can be caused and list down its signs and symptoms?
Type: Short Difficulty: Easy
<p>The cause of measles is a virus that replicates in the nose and throat of an infected child or adult.</p>
<p>When someone with measles coughs, sneezes or talks, infected droplets spray into the air, where other people can inhale them. The infected droplets may also land on a surface, where they remain active and contagious for several hours.</p>
<p> Measles signs and symptoms appear 10 to 14 days after exposure to the virus. Signs and symptoms of measles typically include:</p>
<p>- Fever</p>
<p>- Dry cough</p>
<p>- Runny nose</p>
<p>- Sore throat</p>
<p>- Inflamed eyes (conjunctivitis)</p>
<p>- A skin rash made up of large, flat blotches that often flow into one another</p>
Q3:
How it can be treated and managed by drugs?
Type: Short Difficulty: Easy
<p>_ Post-exposure vaccination. Nonimmunized people, including infants, may be given the measles vaccination within 72 hours of exposure to the measles virus to provide protection against the disease.</p>
<p>_ Immune serum globulin. Pregnant women, infants and people with weakened immune systems who are exposed to the virus may receive an injection of proteins (antibodies) called immune serum globulin.</p>
<p>_ Medications</p>
<p>-Fever reducers. You or your child may also take over-the-counter medications such as acetaminophen, ibuprofen or naproxen (Aleve) to help relieve the fever that accompanies measles.</p>
<p>-Antibiotics. If a bacterial infection, such as pneumonia or an ear infection, develops while you or your child has measles, your doctor may prescribe an antibiotic.</p>
<p>- Vitamin A. People with low levels of vitamin A are more likely to have a more severe case of measles.</p>
Q4:
What are the risk factor of measles?
Type: Short Difficulty: Easy
<p>_ Traveling internationally. If you travel to developing countries, where measles is more common, you're at higher risk of catching the disease.</p>
<p>- Having a vitamin A deficiency. If you don't have enough vitamin A in your diet, you're more likely to contract measles and to have more-severe symptoms.</p>
Q5:
How measles can be prevented and list down its complication?
Type: Short Difficulty: Easy
<p>_ Administration of measles vaccine within one year of age.</p>
<p>_ Isolation of a patient: strict avoidance of close contact with a patient.</p>
<p>_ Others precautionary .easures are needed as applied to air born infection.</p>
<p>_ Proper disposal of contaminated waste.</p>
<p> </p>
<p>Complications</p>
<p>_ Otitis media</p>
<p>_ Pneumonia</p>
<p>_ Bronchitis</p>
<p>_ Diarrhoea</p>
<p>_ Encephalitis</p>
<p>_ Activation of tuberculosis</p>
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Organ system of Hirudinaria granulosa.
Organ system of Hirudinaria granulosa.
The organ system of Hirudinaria granulosa consists of the Digestive system,Respiration system, Reproductive system, Excretory system.
Digestive system of Hirudinaria:
The digestive system of Hirudinaria consists of Alimentary canal,Food, feeding and digestion,Absorption and egestion.
1. Alimentary canal:
The alimentary canal of leech, is a complete straight tube of varying diameter, extending from mouth to anus. It is differentiated into buccal cavity, pharynx, oesophagus, crop, stomach, intestine, and rectum.Buccal cavity,pharynx, and rectum are lined by ectodermal epithelium covered by cuticle.They form stomodaeum and proctodaeum , respectively, while the rest of gut is lined internally by ectodermal epithelium and form mesenteron. The Greater part of the alimentary canal is concerned with for the storage of un coagulation blood and very small is concerned for the digestion, absorption, and secretion.This modification is strictly in accordance with the sanguivorous habit of leech.
1. Stomodaeum:
It comprises of pre-oral buccal cavity and pharynx.
i. Pre-oral:The preoral chamber is a cup-shaped on the ventral side of the anterior sucker.Its roof is formed by a membrane-like velum bearing a triradiate opening, the mouth, in the centre. One ray or chink of mouth is mediodorsal while the other two are ventrolateral.At the base of the pre-oral chamber lies the tri-radiate mouth guarded by velum, which forms the lip of the mouth.
ii. Buccal cavity:The triradiate mouth leads into a very short chamber, the buccal cavity.In the mucous membrane of a buccal cavity are embedded three crescentic jaws, one mid-dorsal and the other two are a lateral ventral position. Each jaw is laterally compressed cushion, covered with a fine cuticle which is thickened at the free edge to form a dentigerous ridge bearing a row of minute teeth (denticles). The median jaw bears 103 to 128 teeth, while the lateral jaws bear 85 to 115 teeth each.on both the sides of jaws are small button-shaped slavery papillae, each bearing number of opening of salivary glands. The number of papillae is 42 to 45 on each side of the jaw.H
ii,Pharynx:Buccal cavity leads into the thick muscular walled pharynx. It is an oval sac extending from five to eight segments.Its inner surface bears longitudinal folds. The muscle of the pharynx are circular and radial which join the pharyngeal wall to the body wall; radial muscles dilate the pharynx producing a pump- like action for sucking blood. Large masses of unicellular perform salivary gland surround the pharynx which contains a substance called hirudin which prevents the coagulation of blood of the host hen the leech is sucking.
2. Mesenteron:
It consists of oesophagus crop,Intestine, and stomach.
i. Oesophagus:
It is the remarkable short and narrow tube through which pharynx leads into the crop. It has a narrow lumen and a much folded epithelial lining.
ii.
ii.Crop:
It comprises the largest portion of the alimentary canal.It is a thin-walled extensive tube, occupying about two-third of the visceral space and extending from nine segments to eighteen segments. It has ten thin walled chambers, one in each segment and they are connected with one another by more or less circular apertures surrounded by the sphincter. Each chamber consists of a number of a small anterior and broad posterior part which is produced by a pair of lateral outgrowths, the caeca. The chamber and the caeca go on gradually increasing in size towards the posterior side.The last chamber of the crop is the largest and its caeca are prolonged backwards up to the twenty-second segment. The crop and its caeca are greatly extensible and used for sorting blood, one cropful of blood lasts for several months and digested slowly.
iii. Stomach:,
Posteriorly, the last member of crop ends into a funnel-shaped tube.It leads through a sphincter aperture into a small heart-shaped stomach, lying in the 19th segment. The mucous lining of the stomach is thrown into anastomosing transverse folds.
iv. Intestine:
Posteriorly, the stomach leads into the intestine. It is thin walled, straight narrow tube running from the 20th to 22nd segment .Its inner lining is thrown into numerous spiral folds and villi-like processes which increase its absorptive surface.
3. Propodeum:
Propodeum consists of rectum and anus.
.
i.Rectum:
The intestine opens into short, thin-walled somewhat ciliated rectum running from 22nd to 26th segments. It collects undigested food.
ii. AnusThe rectum opens by a dorsal anus in the 26 the segment above the posterior sucker. Undigested food is egested through the anus.
History of alimentary canal:
Alimentary canal consists of a layer of columnar epithelial cells separated by a basement membrane from an outer layer of connective tissue. Columnar epithelium is lined by cuticle in the fore and hind gut . It is also ciliated in the hindgut and contains haemo coelomic capillaries and circular muscle fibre. In the pre-oral chamber,r it contains circular muscle fibres as well as longitudinal muscle fibres, while in the pharynx it contains circular, longitudinal and radial fibres.
Digestive gland of Hirudinaria Granulosa:
The digestive gland includes salivary glands and other isolated gland cells found in the mucous membrane of the gut wall.
A.Salivary gland.
These are unicellular , pyriform, glandular mass of cell situated around and behind the pharynx. Each glandular cells has elongated fine ductile which finally enters the jaws to open in raised salivary papillae. The secretion of this gland contain an anticoagulant substance called hirudin, hirudin prevents coagulation of blood so that the leech can suck blood effectively and for the longer duration to fill up its crop and ceca.
B. Gland cells.These are in the form of goblet cells, found scattered throughout the lining of a crop.These secreted mucus in the crop.
2 Food feeding and digestion:
Since each is sanguivorous in -habit, it feeds on the blood of cattle.In feeding the leech applies its oral sucker to the skin of its victim, the jaw move towards and away from each other, they painlessly puncture the skin. The pump-like action of the pharynx sucks in large quantities of blood to fill the crop;secretion of hirudin prevents coagulation of blood. In the crop, the blood is haemolysed in which corpuscles burst, haemoglobin gets dissolved in the plasma and the blood become dark,red this blood slowly passed through sphincter aperture into the stomach where it turns green and is digested,but the haemoglobin of ingested blood is absorbed directly by the cells of the stomach. Globin of ingested blood is mainly used as food. A cropful of blood taken 10 or 14 months for complete digestion. So digestion process is slow.
Abderhalden and Heise (1909) found a pectolytic ferment which hydrolyses proteins in an alkaline medium.However, digestion has been reported to occur entirely by gut bacteria in Hirudo (Busing at el, 1953).
3. Absorption and egestion:
i. Absorption:
Digested blood is slowly absorbed in stomach and intestine, the walls of which have numerous folds and haemo coelomic branches. Complete digestion and absorption of a full meal may take about a year or even more.
ii. Egestion.
Undigested food is stored temporarily in the rectum.Egestion is accomplished through the anus.
Respiratory system:
There is no special organ of respiration in Hirudinaria. Besides being a protective covering, the skin also serves a respiratory function. Capillaries containing haemo coelomic fluid extend in between the cells of the epidermis, which act as the permeable membrane ,through which exchange of gases takes place by diffusion. Carbon dioxide of haemo coelomic fluid passes out and oxygen dissolve in water goes in. Skin is always kept et by the surrounding water, while mucus secreting by epidermis slime water, also prevent it from drying on exposure.
Reference:
Bibliography
https://en.m.wikipedia.org/wiki/Main_Page
Agrawal Sarita. A Text Book of Biology,New Delhi.: Madhuban Educational Books, 2011.
Bhamrah, H.S., and Kavita, Juneja. A Text Book of Invertebrates, New Delhi: Anmol Publications Pvt Ltd, 2011.
Jordan E.L. and P. S., Verma. Invertebrate Zoology, New Delhi,: S. Chand and Company Pvt. Ltd., 2011.
Kotpal, R. L., Modern Text Book of Zoology: Invertebrates, New Delhi, India: Rastogi Publications,2011.
http://www.biologydiscussion.com/
http://www.parasitesinhumans.org/
https://web.stanford.edu/class/
https://en.m.wikipedia.org/wiki/Main_Page.
Lesson
Annelids
Subject
Zoology
Grade
Bachelor of Science
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