6Nemathelminthes

πŸ“š
NEMATHELMINTHES
β–’ Introduction:
❖ Features:
β—‰ Body Structure:
  1. Triploblastic
  2. Bilaterally symmetrical
  3. Vermiform
  4. Unsegmented cylindrical
  5. True worms
β—‰ Coelom:
β—ˆ Type: Pseudocoelomate
β—ˆ Details: Pseudocoelom or false coelom derived from embryonic blastocoel.
Image 1
Fig.ladder like nervous system of platyhelmenthes
Credit:Rs' Science
Q1.
The space between the body wall and the alimentary canal of Ascaris is known as
πŸ“…MOE 2052
❖ Body Plan:
β—‰ Type: Tube within a tube body plan
β—‰ Details:
  1. Alimentary canals of roundworms have both mouth and anus.
  2. Digestive tract complete.
Q1.
Which of the following statement is true about the alimentary canal of Round worms?
πŸ“…IOM 2003
❖ Body Organization:
β—‰ Grade: Organ-System grade
β—‰ Systems:
β—ˆ Respiratory and Circulatory:
β–  Status: Absent
β–  Details:
  1. Gaseous exchange occurs by general body surface.
  2. So no blood.
β—ˆ Excretory: Unique, comprised of one or two Renette cells (H-shaped cell), a set of collecting tubules (Protonephridia)
β—ˆ Nervous: Circumpharyngeal nerve ring and six longitudinal nerve cords
β—ˆ Reproductive:
  1. Well developed
  2. Dioecious with sexual dimorphism [First unisexual phylum]
  3. Eggs with chitinous shell
  4. Cleavage: Determinate and Spiral
β–’ Body Covering:
❖ Cross Section: Body round in cross section
❖ Cuticle: Covered with transparent cuticle composed of Scleroprotein
❖ Epidermis: Syncytial epidermis present without cilia
❖ Musculature: Body wall has only longitudinal muscles
β–’ Development:
❖ Growth: Auxetic growth – increase in volume of cells, not number
❖ Eutely: Body made up of fixed number of somatic cells
β–’ Cephalization:
❖ Head: No distinct head
❖ Mouth: Surrounded by lips bearing sense organs
❖ Sensory Structures:
β—‰ Papillae: Tangoreceptor
β—‰ Amphid:
β—ˆ Location: Mouth
β—ˆ Function: Olfactoreceptor in Ascaris
β—‰ Phasmid:
β—ˆ Location: Anus
β—ˆ Function: Chemoreceptor and Glandulo-receptor
β–’ Classification:
❖ Classes:
  1. Rotifera
  2. Gastrotricha
  3. Kinorhycha
  4. Nematomorpha
    5. β—ˆ Nematoda:
    β–  Groups:
    1. Aphasmida
    2. Phasmida
1
Phasmid: -
Phasmid: +
2
Tail: Non-glandular
Tail: Glandular
3
β—‰ Examples:
  1. a. Trichinella spiralis (Thread worm)
  2. β€’ Not a blood parasite
β—‰ Examples:
  1. a. Ascaris lumbricoides (Round worm)
  2. b. Ancylostoma duodenale (Hookworm)
  3. c. Wuchreria bancrofti (Filarial worm)
  4. d. Enterobius vermicularis (Pin worm/ Thread worm/ Seat worm)
  5. e. Necator americanus (New world Hookworm)
  6. 1. Blood parasite
  7. β€’ Hookworms are blood sucking parasites
  8. f. Trichuris trichuria (Whip worm)
  9. g. Loa loa (Eye worm)
  10. h. Dracunculus medinensis (Guinea worm)
Q1.
Amphid and phasmid glands are found in:
πŸ“…IOM 1997
πŸ“š
ASCARIS LUMBRICOIDES (ROUND WORM)
β–’ Ascaris:
❖ General Info:
β—‰ Commonality: Most common endoparasite of man
β—‰ Habitat in Man: Small intestine (mostly in Jejunum)
β—‰ Disease Caused: Ascariasis
Q1.
Special modification of Ascaris to its parasitic mode of life Is:
πŸ“…IOM 1998
❖ Body Structure:
β—‰ Shape: Elongated, unsegmented cylindrical with tapering ends
β—‰ Sex: Dioecious with sexual dimorphism
Q1.
The animal in which sexes can be differentiated from external morphology is
πŸ“…IE 2003
β—‰ Surface Features:
  1. Four longitudinal streaks through semitransparent cuticle
  2. 1 mid-dorsal, 1 mid-ventral, 2 laterals
β—‰ Body Wall:
β—ˆ Layers:
β–  Cuticle:
  1. Thick, four-layered
  2. Secreted by underlying epidermis
  3. Protects from mechanical injury and host digestive enzymes
  4. Parasitic adaptation
β–  Epidermis:
  1. Syncytial (Coenocytic)
  2. Forms dorsal, ventral, and lateral cords by invagination
β–  Muscle Layer: Inner longitudinal muscle only (circular muscles absent)
Q1.
The correct matching about body wall of Ascaris is:
πŸ“…BPKIHS -2015
β—‰ Sexual Dimorphism:
S.N.
Male Ascaris
Female Ascaris
1
Smaller
Bigger
2
Curved tail
Straight tail
3
Cloacal aperture present
Cloacal aperture absent; anus present
4
Pineal setae present in cloacal aperture
Absent
5
55 pairs of anal papillae (50 pre-anal, 5 post-anal)
Absent
6
55 pairs of cloacal apertures (50 pre-cloacal, 5 post-cloacal)
Absent
7
3 apertures
4 apertures
❖ Mouth Structure:
β—‰ Type: Terminal, triradiate
β—‰ Lips:
  1. 1 median dorsal lip
  2. 2 ventrolateral lips
β—‰ Lip Details:
S.N.
Medial Dorsal Lip
Ventrolateral Lips
1
2 labial papillae (Tangoreceptor)
1 in each lip
2
Absent
1 simple lateral papilla (Chemoreceptor) in each
3
Amphid absent
Amphid (Chemoreceptor/Olfactoreceptor) in each
Q1.
Amphids present in ventrolateral lips of Ascaris are:
πŸ“…IOM-2013
❖ Digestive System:
β—‰ Alimentary canal:
Image 1
Q1.
Which of the following statement is true about the alimentary canal of Round worms?
πŸ“…IOM 2003
Q2.
Special modification of Ascaris to its parasitic mode of life Is:
πŸ“…IOM 1998
❖ Excretory System:
β—‰ Lateral Lines: Contain excretory duct
β—‰ Excretory Pore: Midventral, slightly behind mouth
β—‰ Excretory Organ: H-shaped Renette cell
β—‰ Excretory Products:
  1. Ammonia
  2. Urea
❖ Anus and Gonopore:
β—‰ Female Anus: Posterior transverse
β—‰ Gonopore: Ventral, 1/3 from anterior end
❖ Nutrition:
β—‰ Type: Holozoic
β—‰ Feeding: Feeds on predigested food of host
β—‰ Digestion: Mainly extracellular
β—‰ Salivary Glands: Absent
β—‰ Reserve Food: Glycogen in syncytial epidermis
❖ Respiration:
β—‰ System: Absent
β—‰ Type: Anaerobic
❖ Circulatory System: Absent
❖ Nervous System:
β—‰ Structure:
  1. Nerve ring around pharynx (circumenteric)
  2. Nine ganglia attached to nerve ring
  3. Includes ganglia and longitudinal nerves
❖ Sense Organs:
  1. Labial papillae
  2. Cervical papillae
  3. Anal papillae
  4. Amphids
  5. Phasmids
❖ Reproduction:
β—‰ Sexuality: Dioecious / Unisexual
β—‰ Male Reproductive Organs:
  1. Unpaired testis (Monorchic, Telogonic)
  2. Only anterior part of testis functional
  3. Vas deferens
  4. Seminal vesicle
  5. Ejaculatory duct
  6. Cloaca
  7. Pineal setae
  8. Sperm: Amoeboid, asymmetrical, no flagella
β—‰ Female Reproductive Organs:
  1. Paired ovaries (Diorchic / Didelphic, Telogonic)
  2. Oviducts
  3. Uteri
  4. Median vagina
❖ Life Cycle:
β—‰ Eggs:
β—ˆ Fertilization: In lower part of uteri
β—ˆ Ejection: Via feces
β—ˆ Type: Monogenetic
β—ˆ Structure:
  1. Mammilated (protein coat with rippled surface)
  2. Oval shaped
  3. Three coverings: outer protein layer, middle chitinous shell, inner glycoside membrane
β—ˆ Development Conditions: External (soil); requires low temperature, oxygen, moisture
β—ˆ Viability: Infective larvae viable in soil for 2+ years
β—‰ Larval Development:
β—ˆ Stages:
  1. Zygote to first-stage juvenile in 10–14 days
  2. First-stage larva (rhabditiform) not infective
  3. Second-stage larva (rhabditiform) is infective after first molt inside egg
  4. Transmission: Contaminated food/water
  5. Viable up to 6 years in environment
β—ˆ Hatching: In duodenum after ingestion
Q1.
The wandering journey of Ascaris takes:
πŸ“…IOM 1996
β—ˆ Migration:
β–  Primary: Intestinal wall β†’ hepatic portal vein β†’ liver β†’ heart β†’ lungs
β–  Secondary: Lungs β†’ trachea β†’ pharynx β†’ intestine
β–  Aberrant: Lungs β†’ spleen/liver/lymph nodes/brain/eyes
β—ˆ Diseases During Migration:
  1. Appendicitis
  2. Pneumonia
  3. Bronchitis
  4. Brain hemorrhage
β—ˆ Journey Duration: 3 weeks (intestine to intestine)
β—‰ Moulting:
Moulting
Location
Larval Stage
1st moulting
Soil
2nd instar / Infective rhabditiform larva
2nd moulting
Lungs
3rd instar larva
3rd moulting
Lungs
4th instar larva
4th moulting
Small intestine
Adult (Sexually mature)
β—ˆ Notes:
  1. Second and third moults occur in lungs
  2. Final moult in intestine is essential for survival and maturation
Q1.
Which one of the following is true for Ascaris?
πŸ“…IOM 1997
Q1.
Which one has no intermediate agent to cause disease?
πŸ“…BPKIHS-2013
πŸ“š
ANCYLOSTOMA DUODENALE (HOOK WORM)
β–’ Hookworm:
❖ General Info:
β—‰ Parasitism: Monogenetic
β—‰ Habitat: Small intestine of human
β—‰ Feeding: Sanguivorous (feeds on blood)
β—‰ Disease Caused: Ancylostomiasis
❖ Infection:
β—‰ Mode: Penetration of soft skin of soles
β—‰ Prevention: Wearing slippers prevents infection
❖ Infective Stage: Filariform larva (3rd stage)
❖ Moulting:
Moulting
Place
Larval Stage (Filariform)
1st moulting
Soil
2nd stage Filariform larva
2nd moulting
Soil
3rd stage Filariform larva (Infective stage)
3rd moulting
Oesophagus
4th stage Filariform larva
4th moulting
Small intestine
Adult
❖ Reproduction:
S.N.
Male Hookworm
Female Hookworm
1
Copulatory bursa with bursal rays present
Absent
2
Cloaca
Anus
❖ Mouth Features:
β—‰ Teeth: 3 pairs total - 2 pairs ventrally and 1 pair dorsally
❖ clinical features: causes iron deficiency anaemia
Q1.
Which of the following parasite causes iron (Fe) deficiency anaemia?
πŸ“…IOM-2013
πŸ“š
WUCHRERIA BANCROFTI (FILARIAL WORM)
β–’ Larva: Microfilaria
β–’ Causes: elephantiasis
β–’ Common site of Elephantiasis: Foot
Q1.
Filaria is a:
πŸ“…IOM 1997
Q2.
Filaria can be eradicated if the population of following is exterminated
πŸ“…BPKIHS 2004
Q3.
Which of the following disease is caused by nematodes?
πŸ“…MOE 2063
Q1.
Which of the following statement is true about the alimentary canal of Round worms?
πŸ“…IOM 2003
Q2.
Special modification of Ascaris to its parasitic mode of life Is:
πŸ“…IOM 1998
Q3.
Filaria is a:
πŸ“…IOM 1997
Q4.
Which one of the following is true for Ascaris?
πŸ“…IOM 1997
Q5.
Amphid and phasmid glands are found in:
πŸ“…IOM 1997
Q6.
The wandering journey of Ascaris takes:
πŸ“…IOM 1996
Q7.
Which of the following disease is caused by nematodes?
πŸ“…MOE 2063
Q8.
The space between the body wall and the alimentary canal of Ascaris is known as
πŸ“…MOE 2052
Q9.
The animal in which sexes can be differentiated from external morphology is
πŸ“…IE 2003
Q10.
Filaria can be eradicated if the population of following is exterminated
πŸ“…BPKIHS 2004
Q11.
Amphids present in ventrolateral lips of Ascaris are:
πŸ“…IOM-2013
Q12.
Which one has no intermediate agent to cause disease?
πŸ“…BPKIHS-2013
Q13.
The correct matching about body wall of Ascaris is:
πŸ“…BPKIHS -2015
Q14.
Which of the following parasite causes iron (Fe) deficiency anaemia?
πŸ“…IOM-2013
Q15.
Which of the following penetrate through human skin?
πŸ“…BPKIHS-2016
Q16.
In hookworm, ingested blood is prevented from clotting by formed secreted by:
πŸ“…IOM-2015
Q17.
The alimentary canal of nematode is:
πŸ“…IOM-2015
Q18.
Hookworm infection causes the deficiency of:
πŸ“…IOM-2016
Q19.
Filariform larva is infective stage of:
πŸ“…IOM
Q20.
The organism which is NOT blood parasite:
πŸ“…IOM
Q21.
After how many moults does a round worm grow into an adult in human intestine?
πŸ“…KU 2014
Q22.
Anemia may be caused by
πŸ“…KU 2012