micro sheet # 2 Dr. 7assan -Ala2

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micro sheet # 2 Dr. 7assan -Ala2

Post by Shadi Jarrar on 28/4/2011, 9:34 pm

بسم الله الرحمن الرحيم


Look to 1st handout while u r studying<<< intoduction to parasite>>>
Parasite ********************************************************
* We talked about classification of primary and intermediate host.
* Intermediate host usually an insect (Vector).
* Transmission of parasite from one primary host to another sometimes it
can take a direct route without an intermediate host but in others they need intermediate host
( depends on the kind of parasite)
*dividing into: - unicellular protozoa
multicellular helminthes
* We can distinguish protozoa from other that they divide by (binary fission) So they can multiply within the host.
* Worms stay statics (they can't divide) but protozoa can, They produce eggs but eggs don't hatch in the host, the eggs produce from export ( export to some other host ) .
* Transmission of Disease in Protozoa
You can have direct transmission from one host to another without an intermediate host (and in that case we need an intermediate stage which is resistance) which is the (cyst).
* Trophozoites do not transmit the disease, so released to transporting to a cyst (cyst is a resistance form of parasite and this pass inside the body and then goes to infect somebody else).
* We said if there is an intermediate host, then we don't need a cyst , we only need a cyst if there is no intermediate host.
*but Malaria don't need an intermediate host they only need a cyst so traphozoites are transmitted from one person to another.
1. Nematodes :-
* Round worms * size range from ( 2 mm – 1m )
* Most of them r luminal nematodes (live inside lumen).
* Few of them are tissue nematodes.
* They have complete GI tract (with anal opening and oral opening).
* No circulatory system.
* They have rudimentary CNS, rudimentary excretory system.
* They have separate sexes (some of them are females with female reproductive system and others are males with male reproductive system).
We need present both sexes to produce fertile eggs.
* the luminal Nematodes ( which are the majority of nematodes) produce Eggs and the eggs pass to feces and then they can pass to other host.
*the tissue Nematodes can live in lymphatic's, circulatory system, subcutaneous tissue, And these can only transmitted through an intermediate host, Intermediate host usually an insect (Mosquitoes) we call it vector.
* Tissue Nematodes don’t produce eggs. (they produce larva's مثل الولادة))) Present in
blood, Musquitoes comes and bites the person then develop in , It then they go to bites somebody else and transmit the disease to That person.
* So we have two route of transmission
1 . By intermediate host ( which is normal by insect ( mosquitoes)).
2 . Through eggs that produce in v large No. (reach 10-15 thousand sometimes).
These will not hatch in the body of primary host, They will pass in feces and then mature in soil and if eaten by somebody else, they hatch in that person.

<<< so it's similar to protozoa (have General route prime of transmission).
Protozoa usually they produce cyst feces infect other
Or a form of trophozoites stick by an intermediate host and
Mosquitoes and goes to transmit somebody else. >>>>>>

* Tissue Nematodes produce larva's and they circulating in blood then transmitted to other people by bites of mosquitoes.
* But majority of them produce eggs and then can fertile.
* So worms can't multiply( the only way to produce their Number is by eating fresh eggs) u need to have a source of eggs .
* Therefore protozoa usually produce more severe disease than worm , Bcz it can divide by binary fission.

2. Trematodes :
* flattened worms * oval shape like a leaf مثل ورقة الشجر)).
* The size varies from ( 2-6 cm) * They have ledges or spines and these help to anchor the warm to lumen, (They usually present in lumen of GI, usually the peristalsis and secretion and passage through, this is attempt to get rid of worms).
* These worms need to have equipment by which to anchored themselves inside lumen, some of them have teeth, others are v.muscular they can keep ,Pushing themselves against the wall of GI tract and by that they can keep attach or pass inside lumen
* so these spines help to anchored inside lumen, in addition to this they Have (suckers)
( (شفاطات that help to stay in position.
* Suckers are 2 in position: (oral suckers) around opening of mouth
( ventral suckers) in front of warms
*suckers together with spines help to keep warms in position.
* have GI tract, it's usually bifurcate (divides into 2 branches ) but they have blind ended of GI (without anal opening). So if anything which indigestive it's actually vegetated to get rid of it..
* They have rudimentary Nervous System (same as Nematode)
* No circulatory system (passage of nutrient through diffusion).
* They have excretory system flame cell. This help to get rid of the waste.
* Reproductive aspect of this warm is ( hermaphotides) .
* hermaphotides it means that warms are both sexes(male and female at the same time).
*trematodes its self fertilized presence of one warm is enough to produce fertile egg. (the sperm comes and fertilized egg in the same warm)
<<< But Nematodes are cross fertilization (separate sex either male or female)>>>>
* Eggs in this case always need an intermediate host ( y3ni u can't have eggs that go outside the body and then eaten by somebody else).
* Eggs will excreted through feces, urine, sputum ----- if eggs expelled
To dry land it will die and will not be able to transmit any disease.
*These eggs have to get access to fresh water Bcz intermediate host is
a fresh water creature which is ( snails) بزاقة\قوقعة .
Morphology of eggs:
large, oval, with an operculumغطاي.
* The eggs mature to an miracidium (miracidiun is a mature creature inside , the operculum egg)
* When the eggs released to water the operculum open and this miracidium (Which is ciliated) comes out of eggs and they can swim in the water.
*If you look on ant. end of miracidium they lack spine, Bcz they swim until find snail and then start to developing inside the tissue of that snail. ( remember that miracidium become spore cyst !!!)
*The net result of the developing through snail is production of thousand of creature known as(crcaria) it has a tail to swim in water
To goes and effect other person, Either by:
1. Ingested by a person Or 2. Penetrated through skin (access to tissue of that person)
(route depend on species).
*if route was by eating ,crcaria will lose its tail and then covered itself by a protective layer known as metacercaria and these will settle on aquatic plant أعشاب مائية or fish, If someone comes and eats this fish or plant without cooking, metacercaria go to G.I tract then will infect lung or ---or --- etc!!!!.

Tremadose in body ----- produce fertilized egg---- pass through either feces ,urine ,sputum ------ Fresh water ------ give rise to mircidium ---- go to snail ----multiply within snail give rise to ( cercania) have tail -----have choice(depend on species) :
1. Infect through skin or 2. They lose its tail and become (metacercaria)
Settling on grass or fish, then they can be eaten by ( next primary host)
Nematodes Trematodes
* Complete G.I with an ( oral and anal opening) * Not Complete G.I
*two separate sexes ( oral without anal opening ( blind ends )
* transmitted with or without intermediate host * both sexes
* more advanced * to transmitted must have intermediate host
*less advanced but more advanced than cytoside
Cestodes (tapeworms) الدودة الشريطية
Tape like, they can be short ( 2 cm) or long ( reach up to 10 meter) *
* Trematodes and Nematodes can't reach v. long bcz they are consist of distinct unit ( one unit)… but cestodes consist of more than one unit (segment)
( these segments similar or diff. from each other).
the general feature of tape warms
* It has head known as (scolex) help to anchored itself to wall of GI tract by sacker ( usually it has 4 sackers).
* Sometimes in addition to sacker we can have a rope or double rope
(hook) and those r known as rostellum.
* ant. end of warm known as scolex, to anchoring warm to intestine and this usually done by 4 sucker and a rope of hooks known as rostellum
, * some warms have hooks but some of other don't ( depend on warms)
( hook can be double rope or one rope depend on species).
* After ( scolex) we have body of warm that made of distinct segments known as
( Proglottid), and these segments start ( from neck region/ after scolex) and continue to bottom of warms
* The No. of proglottid depend on the worms and the length of warms(some have only 3 proglottild other have 1-2 thousand proglettid .. depend on species)
* (Moving distally from neck region these proglottid undergo maturation)
* Immediately after neck --------- we have ------ ( immature proglottid)
They are not v. distinctive and they don’t have special Morphology
*as we go medial to warm --------- we have ------- ( mature proglottid)
Mature Proglottid (has just male and female reproductive system in the same segment).
So eggs are produce from ovaries and fertilized by sperms from testis and once they are fertilized they go into uterus,, then uterus become bigger from these fertilized eggs and by time goes to distal third of warm,we can see a staph uterus.
* in distal third we see just uterus full of fertilized eggs--- Uterus become expand, branched------- we have --------- ( Gravid Proglottid)
* Immature Proglottid ----- immediately after neck
* mature Proglottid ------ middle of warms (has male and female reproductive sys.)
* Gravid Proglottid ------ in the last end of warms (uterus full of fertilized eggs)
* These Proglottid at the end start to separating (one by one, or in number 10 or 12 together)
* They get out by feces; eggs are not released by GI tract.
* With tape worms we always need an intermediate host
Intermediate host usually (cow or pigs) ---- come and eat Proglottid.*
* If somebody eat meat of that cows or pigs become infected.

(Look at hand out: scolex/ sackers, nature Proglottid, Gravid Proglottid)

* The morphology of fertilized eggs ( most of them are usually the same)
From outside have Striated cover…and inside the eggs have (embryo) with 6 hooks
(this embryo called hexacamp …. (spelling!!!))
* if intermediate host eat Gravid Proglottid, these eggs in GI of the intermediate host will disintegrate and release hexacamps.
* hexacamps has 6 kooks that connect to the wall of intestine and then penetrate the wall of small intestine of host and then distribute to blood stream to all tissue of intermediate host.
* when they settle in the tissue , they develop into ------ ( cysticercus)---- ( which is balloon contain clear yellowish fluid, and invaginated from the balloon is sth that resembles scolex ( rudimentary scolex )), so If we eat meat (of intermediate host) without cooking … then the cysticercus will evaginated in small intestine and here it's really a scolex , anchored to wall of intestine and then start to proliferation from neck region to give rise immature , Mature And gravid proglottid and then we have new tapeworm in that person.

Ala2 istanbuli
2nd lec. for dr.7assan 

"من باع حريته لأجل أمنه فإنه لا يستحق أيَاً منهما" بنيامين فرانكلين
اللهم احفظ أردننا

Shadi Jarrar
مشرف عام

عدد المساهمات : 997
النشاط : 12
تاريخ التسجيل : 2009-08-28
العمر : 26
الموقع : Amman-Jordan


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