MPSC Excretory System(उत्सर्जन संस्था)-MPSC Biology science notes

Excretory System

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Excretory System(उत्सर्जन संस्था))

Introduction of Excretory System

➤ The Process in which the waste material is removed by the body system is called as human Excretory System.
➤ Our human body is a big experimental vessels and it conduct lots of chemical reaction everyday.
➤ As biochemical Reaction occurs in the human body it produces with a lots of waste materials which is harmful to human body.
➤ If body does not perform a execration process it may causes a very hard effects.
➤ Process of excretion may vary as per the physical structure of living animals.
➤ The skin excretes largest part of a body by sweating.
➤ The lungs are the main organ of the respiratory system.
➤ It balances the proper amounts of water, salts, and nutrients .

✪ Excretion In Living Animals ✪

➤ Generally Animals execrate the nitrogen in large amount.
➤ Following are the main components excretes by the human body.
  1. Ammonia:

    ➤ This is a most poisonous excretion element excreted by body .
    ➤ Required Large Amount of water to execration.
    ➤ It takes 500 ml water to remove 1 Gm of ammonia.
    ➤ This is occur in the group of fish , protozoans, echinoderms, praetorians and crustaceans.

  2. Urea:

    ➤ This is less poisonous excretion element excreted by body as compare to ammonia
    ➤ It takes 50 ml water to remove 1 gram of urea
    ➤ Almost All Mammals and marine fish(salty water fish ) excrete urea.
    ➤ In mammals it produce in liver.

  3. Uric Acid:

    ➤ Least Poisonous Excretion Element.
    ➤ It takes very less amount of water to remove from body.
    ➤ This is produced in liver by Ionosinic Pathway

  4. Guanine:

    ➤This is not produced by human body
    ➤ Generally produces by arachnids (Animals with 8 legs )

✪ Human Excretory Systems ✪

➤ The human Excretory system defend on following factors.
  1. Pair of kidney
  2. Pair of Ureter
  3. Urinary Bladder
  4. Urethra

1.Pair Of Kidney

➤The human body have pair of kidney in the stomach.
➤ Right kidney and left kidney.
➤ the weight of kidney is 125GM to 170 gm in a male body.
➤ It is near about 115Gm to 155 Gm in female body
➤ Right kidney placed little bit down side as compare with left kidney
➤ thee shape of kidney is convex from outsider and concave from inner that inner part is hilus

2. Pair Of Ureter➤ureters are tubes made of smooth muscle that propel urine from the kidneys to the urinary bladder.
➤ human adult, the ureters are usually 25–30 cm (10–12 in) long and around 3–4 mm (0.12–0.16 in) in diameter.
3. Urinary Bladder➤bladder is a muscular sac in the pelvis, just above and behind the pubic bone. When empty, the bladder is about the size and shape of a pear..
➤ Urine is made in the kidneys and travels down two tubes called ureters to the bladder.
➤ bladder stores urine, allowing urination to be infrequent and controlled.
➤ The normal capacity of the bladder is 400-600 mL.

4. Urethra

:➤The urethra is a thin, fibromuscular tube that begins at the lower opening of the bladder and extends through the pelvic and urogenital diaphragms to the outside of the body, called the external urethral
➤ It is approximately 4 cm in length for females, whereas it is about 20 cm in the male body.
➤ The Mains function of the ureter is to allow the passage of urine to outside the body for excretion

Nephron And Its Functions

➤ The structural and functional unit of kidney is called as Nephron.
➤ All Urine produced in a nephron.
Followings are the working units of nephron.
nephron structure

Bowmans Capsule

➤ Sir William Bowman 1892 English surgeon
➤ he filtration structure in the mammalian kidney that generates urine in the process of removing waste and excess substances from the blood.
➤ Blood pressure forces plasma minus its macromolecules (e.g., proteins) from the glomerular capillaries into the Bowman’s capsule.
➤ Bowman’s capsule surrounds the glomerular capillary loops and participates in the filtration of blood from the glomerular capillaries
➤ Bowman’s capsule also has a structural function and creates a urinary space through which filtrate can enter the nephron and pass to the proximal convoluted tubule
➤ The first step of filtration occurs through the endothelial layer of the capillaries, which is composed of fenestrated endothelial cells


➤ The glomerulus is a ball of capillaries surrounded by the Bowman’s capsule into which urine is filtered.
➤ he filtration barrier consists of 3 components: Endothelial cells of glomerular capillaries Glomerular basement membrane Epithelial cells of Bowman’s Capsule (podocytes)
➤ Glomerular filtration is the first step in making urine
➤ The glomerulus in the kidney was so named by the Italian anatomist Marcello Malpighi (1628-1694)
➤ It is literally a "little ball of yarn


It IS a proximal convoluted tubule (PCT)
➤ Those content which are very useful to body is bring back by the Pct
➤ The PCT regulates pH of the filtrates by exchanging hydrogen ions
➤ PCT is responsible for reabsorbing 50–60% of the glomerular ultrafiltrate
➤ he PCT is responsible for reabsorbing most of the glucose, amino acids, and small peptides that enter the ultrafiltrate

Loop Of Henle

➤ long U-shaped portion of the tubule that conducts urine within each nephron of the kidney
➤ The principal function of the loop of Henle is in the recovery of water and sodium chloride from urine
➤ he loop of Henle can be divided into three main segments: the thin descending limb, the thin ascending limb, and the thick ascending limb (sometimes also called the diluting segment).
➤ The liquid entering the loop of Henle is the solution of salt, urea, and other substances passed along by the proximal convoluted tubule, from which most of the dissolved components needed by the body
➤ In a healthy person the reabsorption of salt from the urine exactly maintains the bodily requirement


➤ discrete cosine transform(Dct)
➤ The main function of DCt is to secrete the things which are not required for a body
➤ The DCT, first proposed by Nasir Ahmed in 1972
➤it plays a critical role in a variety of homeostatic processes, including sodium chloride reabsorption, potassium secretion, and calcium and magnesium handling
➤Tubular Secretion Take place at DTC

✪ The Process OF Urine Formation ✪

➤This Process took place in a kidney and it process throw 4 stages
  1. Filtration
  2. :glomerulus filter a blood and conduct all filtered element in a bowman capsule.
  3. reabsorption
  4. :Pct reabsorb the material which require to body like salt,sugar.
  5. Secretion
  6. Dct conduct the process of secrete a element like urea ,uric acid.
  7. Exertion
  8. This is a last process in the excretion and true urine produces here.

Important Facts And Point Of Excretory System

➤ Generally both kidney filter almost 1200 ml blood.
➤ Generally 2000 ml urine produced in human body everyday.
➤Urine Ph is 6.0 it is acidic in nature.
➤ urochrome is the chemical primarily responsible for the yellow color of urine
➤ Each Nephrone has length of 3 cm and diameter of 20-60 micrometer
➤DCT controls the acidity of a body
➤ H+ ion secreted by DCT
➤ Eccrine sweat glands help to maintain homoeostasis, primarily by stabilizing body temperature. Derived from embryonic ectoderm, millions of eccrine glands are distributed across human skin and secrete litres of sweat per day.

Excretory Disease

✪ Uremia-Content of urea became very have in blood i.e almost 0.05%
✪ Hematuria-Presence of blood in a person's urine
✪ Glycosuria- Glycosuria is the excretion of glucose into the urine- High Respiration Rate
✪ Kidney stone- Formation of calcium stone near bladder.
✪ Polyuria-Polyuria is a condition where the body urinates more than usual and passes
✪ Anuria- Anuria is nonpassage of urine.
✪ oliguria- Low urine output can have causes that aren't due to underlying disease
✪ milky urine- a White color urine due to increase in phosphate concentration

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