Circulatory Pathways - 1 (Class IX)

Paramecium is a unicellular organism and shows streaming movement called cyclosis. It helps in intracellular circulation and distribution of materials in the cells.

In hydra, internal circulatory fluid is absent. Thus, it uses external medium (water) as circulatory fluid.

Flatworms transport digested food through parenchyma. They exhibit parenchymal circulation.

Food transport takes place with the help of pseudocoelomic fluid.

The walls of the arteries have smooth muscle fibre that contract and relax under the directions of the sympathetic nervous system. They have very thick walls. These blood vessels help in transporting blood away from heart. Except the pulmonary artery, all arteries carry oxygenated blood.

Pulmonary circulation is the portion of the cardiovascular system which carries deoxygenated blood away from the heart to the lungs and returns oxygenated (oxygen-rich) blood back to the heart.

The heart is not a part of lymphatic system. It belongs to the circulatory system. It is located in the center of the chest.

Blood is sometimes considered to be a fluid connective tissue because of the mesenchymal origin of its cells.

The SA (sinoatrial) node is a section of the nodal tissue that is located in the upper wall of the right atrium. The SA node is also referred to as the pacemaker of the heart.

The stethoscope is an acoustic medical device for auscultation or listening to the internal sounds of an animal or human body. It typically has a small disc-shaped resonator that is placed against the chest and two tubes connected to earpieces. It is often used to listen to the sounds of lungs and heart.

Platelets help in blood clotting.

Sucrose is transferred into the phloem tissue using energy from ATP. This increases the osmotic pressure of the tissue, causing water to move into it. This pressure moves the material in the phloem to tissues which have less pressure.