Passive Transport
Passive transport is the transport of any molecules which does not require any energy. It can be divided into two categories.
Diffusion: The process where molecules spread out across space naturally. It is when molecules naturally move from an area of high concentration to an area of low concentration, sometimes through simple membranes. This is the most basic form of molecule movement within the body and happens in many areas. .
Osmosis: Slightly different to diffusion as it concentrates on the movement of water across a semi-permeable membrane (such as a cell membrane) to equalise the concentration of water both out of the membrane and within the membrane. Osmosis makes sure that on either side of a membrane, the concentration of water is the same.
Take a look at the video below for a quick revision on diffusion within cell biology.
Diffusion: The process where molecules spread out across space naturally. It is when molecules naturally move from an area of high concentration to an area of low concentration, sometimes through simple membranes. This is the most basic form of molecule movement within the body and happens in many areas. .
Osmosis: Slightly different to diffusion as it concentrates on the movement of water across a semi-permeable membrane (such as a cell membrane) to equalise the concentration of water both out of the membrane and within the membrane. Osmosis makes sure that on either side of a membrane, the concentration of water is the same.
Take a look at the video below for a quick revision on diffusion within cell biology.
Being Passive in the Kidney
Passive transport occurs commonly within the kidney in various parts of its anatomy. This usually occurs within the nephron and is as follows:
Firstly, small soluable molecules can passively diffuse into the liquid in Bowman's Capsule from the Glomerulus. These molecules are usually molecules of glucose, urea, salts and water and diffuse from the capillaries into the solution of plasma without the use of energy. This particular action is known as passive filtration as blood pressure plays a part in forcing the blood into the Glomerulous.
Secondly, in both the proximal convoluted tubule and the loop of Henle, osmosis of water occurs whereby the water moves from the more concentrated environment within the tubules to the less concentrated environment of the capillaries. This therefore creates a balanced concentration of water within and outside the tubules throughout the nephron network. Depending on the release of the hormone ADH, water can diffuse out of the collecting duct into the nearby capillary. This action is used when water needs to be conserved within the body and is because ADH makes the walls of collection duct permeable to water.
Thirdly, salts can passively diffuse out of the thin walled section of the ascending limb of the loop of Henle and into the Medulla.
Firstly, small soluable molecules can passively diffuse into the liquid in Bowman's Capsule from the Glomerulus. These molecules are usually molecules of glucose, urea, salts and water and diffuse from the capillaries into the solution of plasma without the use of energy. This particular action is known as passive filtration as blood pressure plays a part in forcing the blood into the Glomerulous.
Secondly, in both the proximal convoluted tubule and the loop of Henle, osmosis of water occurs whereby the water moves from the more concentrated environment within the tubules to the less concentrated environment of the capillaries. This therefore creates a balanced concentration of water within and outside the tubules throughout the nephron network. Depending on the release of the hormone ADH, water can diffuse out of the collecting duct into the nearby capillary. This action is used when water needs to be conserved within the body and is because ADH makes the walls of collection duct permeable to water.
Thirdly, salts can passively diffuse out of the thin walled section of the ascending limb of the loop of Henle and into the Medulla.