Page 31 - 11-Bio-14 Transport

14. Transport eLearn.Punjab

Table 14.1 Comparison between closed and open circulatory systems.

Closed circulatory system e.g. Open circulatory system e.g.

Earthworm (Pheretima) cockroach (Periplaneta)

1. Blood always remain in the blood vessels, and 1. Blood does not remain enclosed in the blood

does not come in direct contact with other cells vessels and comes in direct contact with other

of the body. body cells, and bathes them.

2. Inter connected system of arteries , veins, and 2. There are no typical arteries, veins, and

capillaries present. capillaries and for much of the time the blood

called haemolymph flows in the cavities or

sinuses of body cavity (hoemocoel) around the

viscera (perivisceral sinus) and around the nerve

cord (perineural sinus).

3. Exchange of nutrients and waste products 3. Exchange of nutrients and waste products

between the blood and tissues via tissue fluid between the blood and tissues occurs when

occurs through capillaries. blood directly bathes the tissues.

4. The system also transports gases i.e. oxygen 4. This sytem does not transport gases i.e.

and carbon dioxide. oxygen and carbon dioxide (these gases are

transported by tracheal system).

5. Respiratory pigment haemoglobin is dissolved 5. No respiratory pigment and blood is colourless

in blood. Nucleated white blood cells are present. in which nucleated white blood cells float.

6. This is regarded as the most advanced type, 6. This is regarded as primitive having lesser

having greater efficiency, maintaining the blood efficiency and does not maintain blood pressure.

pressure and economy of blood volume.

7. In earthworm there are 4 or 5 pairs of lateral 7. In cockroach the heart is 13-chambered,

hearts present on the lateral side of oesophagus tubular vessel present in the pericardial sinus

in 7th to 13th segments. Hearts pump the blood and placed in mid-dorsal region below terga in

from the dorsal to the ventral blood vessel. abdominal region. On the side of the pericardial

sinus there are alary muscles helping in the

flow of blood. Each heart chamber has a pair of

lateral openings, the ostia.

8. There are three main longitudinally running 8. The portion of the tubular dorsal vessel

blood vessels, dorsal, ventral and sub-neural, which extends in the thoracic and head

which are interconnected through capillaries region is called the “aorta”. It opens

and commissural vessels. anteriorly in the haemocoel of the head by

funnel shaped opening.

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