Mechanism of urine formation, Biology

MECHANISM OF URINE FORMATION -

Production of urine is uripoisis or diuresis. First of all it was explained by Kushney.

Nephron separates acidic urine from basic blood, so maintain acid base balance i.e. Homeostasis (w. cannon).

Process is completed in three stpes -

1.      ULTRAFILTRATION-

  1. Blood along with waste products come in glomerulus by afferent arteriole.
  2. Concentration of urea is more in afferent arteriole. By efferent arterioles only blood moves out.
  3. Diameter of afferent arteriole is more than efferent one. So blood stops in glomerulus for little time.
  4. Here +70 mm Hg GHP (glomerulur hydrostatic pressure) is exerted.
  5. It is balanced by BCOP & CHP.
  6. B.C.O.P. (Blood colloidal osmotic pressure) is due to blood proteins. It is - 30 mm Hg.
  7. CHP (Capsular hydrostatic pressure) is of -20 mm Hg by nephric filtrate of Bowmann's capsule.
  8. So at +20 mm Hg EFP (Effective filtration pressure) such elements having low molecular weight are filtered in glomerulus.
  9. Nephric filtrate is protein less plasma, it is isotonic. Both kidney form 130 ml filtrate / minute.
  10. According to Ludwig process is due to change in pressure.

2.      SELECTIVE REABSORPTION -

  1. In nephric filtrate some essential chemicals are also present as H O, glucose, minerals, A.A.
  2. 90% of nephric filtrate is reabsorbed. These essential chemicals again reach in blood.
  3. Their reabsorption is based on Threshold value. i.e. needed chemicals.
  4. In PCT 80% H2O is reabsorbed by passive transport. It is obligatory absorption.
  5. Rest water is absorbed in DCT under control of ADH. It is facultative absorption.
  6. In PCT glucose, amino acid, minerals are absorbed by diffusion. In PCT solution remains isotonic.
  7. Positive ions are absorbed by active transport.
  8. Negative ions are absorbed by passive transport.
  9. In descending loop H2O is absorbed so solution becomes hypertonic.
  10. In ascending loop NaCl is given out so solution becomes isotonic.
  11. In DCT again NaCl is absorbed so solution becomes hypotonic. It comes in duct of Bellini.

3.      SECRETION -

  1. Richard proved it by experiment. Renal tubule directly discharges heavy waste products in DCT.
  2. It is active process. These chemicals are mainly creatine, pera amino hippuric acid.
Posted Date: 10/2/2012 4:26:34 AM | Location : United States







Related Discussions:- Mechanism of urine formation, Assignment Help, Ask Question on Mechanism of urine formation, Get Answer, Expert's Help, Mechanism of urine formation Discussions

Write discussion on Mechanism of urine formation
Your posts are moderated
Related Questions
Explain Prosthetic device infections Some infectious disease specialists recommend antimicrobial prophylaxis before process in patients with vascular grafts or orthopedic pros

Pathogenesis The mode of intracellular replication of chlamydial agents is investigated morphologically and cytochemically with both light and electron microscope. It is estab

Phase Contrast Microscopy Phase contrast microscope has the resolving power similar to ordinary light microscope. However, it enables us to observe the cellular organelles in liv

Explain the Liver organ? The liver is the largest internal organ in the human body. It lies just below the diaphragm in the upper right area of the abdominal cavity. It is an i

Explain the Acid Fast Staining? Acid fast staining is a type of differential staining used for identification of certain bacteria, e.g. Mycobacteria which cannot be stained rea

DESCRIBE ELECTRON TRANSPORT SYSTEM AND PHOTORESPIRATION

Explain Nelfinavir (NFV, Viracept)  Nelfinavir is a commonly used protease inhibitor because it is well tolerated. It appears to be less potent than lopinavir/ritonavir or efav

Advantages and Disadvantage of using Turbidity Measurement? Advantages 1. It is an easy, rapid and sensitive technique. 2. Turbidity measurement can be done without destr

Q. Define Osseointegration from patients, microscopic and biomechanical points of view. a) From the view of the patient . An implant fixture is osseointegrated if it provid

Q. What do you mean by pollen? Pollen grains are the male gametophytes of the phanerogamic (flowering) plants So within the pollen grains the male gametes of these plants are f