The Importance of the Urinary System Essay

8. What type of membrane does the dialysis tubing represent? Give an example of this type of

In this lab experiment, half our group observed and measured osmosis using dialysis tubes that were represented as the semipermeable membrane. It is permeable to water and other small molecules but is impermeable to larger molecules such as the sucrose solution used in each of the four beakers and tubing. The other half of our group observed the tonicity of sheep blood to determine whether the blood was isotonic, hypotonic, or hypertonic. The 85 g/dL of NaCl solution was the ideal isotonic number in relation to the sheep blood cells as well as a reference to the other observations of the solutions.

We hypothesize that as the solute concentration increases, more water will diffuse into the dialysis tubing (shown by a greater percent increase in mass).

A very carefully regulated process is solute concentration. If there is a sudden increase in water which enters the extracellular fluid, sodium ions will then contribute less to the extracellular solute concentration as the ratio between water and solute has now changed. Osmolality is the amount of solute in a kilogram, hence the osmolality in the extracellular space has also decreased.

Consequently, the efferent arteriole, which filters blood away from the glomerulus, is tinier in diameter than the afferent arteriole, which carries blood into each glomerulus. This puts blood under high pressure in the glomerulus; thus it forces tiny molecules and liquid out of the capillary and into the Bowman’s capsule. Soon afterwards, the tiny and liquid molecules cross the epithelium of the Bowman’s capsule, the basement membrane and capillary wall in order to get into the Bowman’s capsule and to arrive in the nephron tubules. The consequence of this is that the filtrate (the tiny and liquid molecules) pass along the remainder of the nephron and helpful substances are reabsorbed along the route. Last of all, “the filtrate flows through the collecting duct and passes out of the kidney along the ureter” as mentioned by (Parson’s, R: p128).

the kidney nephron. What other substances must be transported from the tubular fluid into the PCT cell

1. What two parameters are responsible for creating the movement (filtration and reabsorption) of fluid across the capillary wall?

This is when the water molecules come from a higher concentration within the body and they then transfer into a region of low concentration, this happens through the partially permeable membranes within the

Formation of urine = in the DCT and collecting ducts, water movement out of the body is regulated by ADH.

Works in conjunction with the blood supply to carry waste products away from the area.

One dialysis tube was submerged in each beaker. Osmosis was allowed to occur for 5 minutes and then all of the tubes were removed from the water. The tubes were dried off and measured on the triple beam scale. The mass was taken and recorded for all three tubes. I then placed the tubes back into their respective solutions. The process was repeated four times for each tube in 5 minute increments, and then the materials were disposed of. The rate of diffusion of water in each solution was

It represents the part of the kidney that acts like a semipermeable membrane, the nephrons. The nephrons are made of membranous tubules that act analogously to the semipermeable dialysis bag. When blood passes through the tubules, particles in the blood leave the tubule by the process of diffusion.

Secondly, osmosis was to be observed to gain a proper understanding of how the principal of dialysis functions.

and other substances that are reabsorbed back into the body. It is also responsible for

Ultra filtration: Ultra filtration results when there is an osmotic gradient or pressure gradient across the membrane. In PD excess fluid is removed by increasing the osmolality of the dialysate with the addition of glucose. In HD , the gradient is created by increasing pressure in the blood compartment(positive pressure)t ore decreasing pressure in the dialysate compartment(negative pressure). Extracellular fluid moves in to the dialysate because of the pressure gradient. The excess fluid is removed by creating a pressure differential between the blood and the dialysate solution.