Ch#14 | Lec #18 | Closed Circulatory system Of Earthworm And Open Circulatory System Of Cockroach

Ch#14 | Lec #18 | Closed Circulatory system Of Earthworm And Open Circulatory System Of Cockroach

Closed circulatory system earthworm.
(Pheretima)
1. Blood always remain in the blood vessels, and does not come in direct contact with other cell of the body.

2. Inter connected system of arteries veins, and capillaries are present.

3. Exchange of nutrients and waste produces between the blood and tissues via tissue fluid occurs through capillaries.

4.The system also transport gases i.e. oxygen and carbon dioxide.

5. Respiratory pigment haemo-globin is dissolved in blood. Nucleated white blood cells are present.

6. This is regarded as the most advanced type, having greater efficiency, maintenance of blood pressure and economy of blood volume.

7. In earthworm there are 4 or 5 pairs of lateral hearts present on the lateral side of esophagus in 7th to 13th segments.

The hearts pumps the blood from the dorsal to the vental vessel.

8. There are three main longitudinally running blood vessels, dorsal, ventral and sub-neural, which are interconnected through capillaries and commissural vessels.

9. The dorsal vessel collects blood from the 14th segment backwards-in the first 13 segments in becomes distributing channel and send its blood to hearts and anterior end of the body ventral vessd is the chief distributing veil with backward flow.

The sub neural vessel is collecting vessel and the flow of blood is backwards.

It communicates with dorsal blood vessel through commissural vessels.

Opening circulatory system e.g. Cockroach:
(Periplaneta)
1. Blood does not remain enclosed in the blood vessels and come in direct contact with other body cells, and bathes them.

2. There are no typical arteries, veins and capillaries and for much of the time the blood called haemolymph flows in the cavities or sinuses of body cavity (Haemocoel) around the viscera (pen visceral sinus) and the nerve cord (perineural sinus).

3. Exchange of nutrients and waste products between the blood and tissue occurs when blood directly bathes the tissues.

4. This system does not transports gases ic. and carbon dioxide (The gases transported tracheal system).

5. No respiratory pigment and blood is colour les which nucleated white blood cell float.

6.This regarded as primitive having lesser efficiency and does not maintain blood pressure.

7. In cockroach the heart is 13- chambered tubular vessel present in the pericardial sinus and placed in mud- dorsal region below terga in abdominal region.

On the side of the heart chambers there are alary muscles helping in the flow of blood. Each heart chambers has a pair of lateral openings, the ostia.

8. The portion of the tubular dorsal vessel, which extends in the Thoracic and head region is called the "aorta". It open anteriorly in the Haemocoel of the head funnel shaped opening.

9.The flow of blood from heart to aorta to haemocoel in head, to pervisceral sinus to per neural sinus to perivisceral sinus to pericardial sinus and to heart through ostia.

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