Tag: Transport

Introduction to the Human Transport System

Introduction to the Human Transport System For simple unicellular organisms only the cell membrane separates the cell from its surroundings.  This means that only diffusion is needed to access the materials they require to support life. When living organisms get more complex, simple diffusion is no longer sufficient and more elaborate ways of transporting oxygen…...

Blood

Blood Blood is a rich red liquid that is transported through the body. The average human has about 5 litres of blood in his/her body. Blood can be considered to be made of 2 parts, plasma and blood cells (red and white blood cells). This may not be noticeable on the first analysis, however after…...

Blood Cells and Platelets

Blood Cells and Platelets There are 3 main types of blood cells- erythrocytes, leucocytes and platelets. Erythrocytes (Red blood cells) These are disc shaped cells with no nucleus, and are produced in the red bone marrow by hematopoietic cells. There are over 5 million of these cells in 1mm3 of blood. These cells are used…...

Functions of blood

Functions of blood Since blood has several components and each of these components have a particular function, then blood serves the collective function of all its sub-units. In other words blood has 3 major functions. 1. Transport and distribution -Transport the material content of the plasma -Transport oxygen and carbon dioxide through the red blood…...

Blood Vessels

Blood Vessels There are 2 types of circulatory systems, closed and open. -Closed circulatory systems: blood stays within the blood vessels. -Open circulatory systems: blood may exit the blood vessels at a point and re-enter at another. Humans have a closed circulatory system, with diffusion occurring across the thin capillary walls to the cells of…...

Circulation in man

Circulation in man Arteries take blood rich in oxygen (oxygenated blood) to the capillary network, which intern feeds the cells in the body. Deoxygenated blood (blood with very little oxygen) is taken back to the heart through veins. It then goes to the lungs where gas exchange occurs so the carbon dioxide can exit the…...

Pumping Mechanism of the Heart

Pumping Mechanism of the Heart The heart muscle has two stages, diastole and systole. Diastole is the state of relaxation and systole is the state of contraction. Blood from the body enters the right atrium through the inferior and superior vena cava. Blood from the lungs enter the left atrium through the pulmonary vein.  The heart…...