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Human Excretory System::

Human Excretory System: PRESENTED BY:Sameer D. Devidas Composed of : KIDNEY-Functional unit of a Kidney- Nephron LUNGS (alveoli) SKIN(sweat glands) LIVER

Human excretory system::

Human excretory system: Waste and What its removed by: CARBON DIOXIDE- lungs WATER - skin, kidney , lungs SALTS - skin, kidney AMMONIA - liver UREA - kidney 10/13/2016 SNEHA'S 2

Excretory System::

Excretory System: 10/13/2016 SNEHA'S 3 The kidneys regulate the amount of water, salts and other substances in the blood. The kidneys are fist-sized, bean shaped structures that remove nitrogenous wastes (urine) and excess salts from the blood. The ureters are tubes that carry urine from the pelvis of the kidneys to the urinary bladder. The urinary bladder temporarily stores urine until it is released from the body.


The urethra is the tube that carries urine from the urinary bladder to the outside of the body. The outer end of the urethra is controlled by a circular muscle called a sphincter. 10/13/2016 SNEHA'S 4

Primary organs OF Excretion::

Primary organs OF Excretion: 10/13/2016 SNEHA'S 5


THE KIDNEY : 10/13/2016 SNEHA'S 6 Each kidney is composed of three sections: The outer (renal) cortex, the (renal) medulla (middle part) and the hollow inner (renal) pelvis. The cortex is where the blood is filtered. The medulla contains the collecting ducts which carry filtrate (filtered substances) to the pelvis. The pelvis is a hollow cavity where urine accumulates and drains into the ureter.

Other Organs::

Other Organs: Ureters - long narrow tubes with expanded upper end (renal pelvis) located inside each kidney. Function is to drain the renal pelvis to urinary bladder Urinary bladder - elastic muscular organ capable of great expansion. Function is storage of urine and voiding Urethra – passage of urine from bladder to outside of body. Passage of semen from male body 10/13/2016 SNEHA'S 7

Blood and Urine Flow:

Blood and Urine Flow B lood enters the kidneys via renal arteries, and leaves the kidneys via the renal veins Wastes removed from the blood leave the kidneys by the ureter 10/13/2016 SNEHA'S 8

Formation of Urine::

Formation of Urine : Occurs by a series of three processes that take place in successive parts of the nephron FILTRATION REABSORPTION SECRETION 10/13/2016 SNEHA'S 9

How blood is Filtered::

How blood is Filtered: The filtering units of the kidneys are the nephrons . There are approximately one million nephrons in each kidney. The nephrons are located within the cortex and medulla of each kidney. The tubes of the nephron are surrounded by cells and a network of blood vessels spreads throughout the tissue. Therefore, material that leaves the nephron enters the surrounding cells and returns to the bloodstream by a network of vessels. 10/13/2016 SNEHA'S 10


The NEPHRON: The nephron begins with Bowman's capsules , which surrounds the glomerulus , a ball of capillaries arising from an afferent arteriole of the renal artery.  Leaving the glomerulus is an efferent arteriole, which forms the peritubular capillaries, where reabsorption takes place.  These spread over the nephron to later form a venule that joins others to make up the renal vein. 10/13/2016 SNEHA'S 11

Parts of the Nephron::

Parts of the Nephron: Each nephron consists of the following parts: 1) glomerulus ; 2) Bowman’s capsule ; 3) proximal tubule ; 4) loop of Henle ; 5) distal tubule ; 6) collecting duct. 10/13/2016 SNEHA'S 12

Nephron in Detail::

Nephron in Detail: 10/13/2016 SNEHA'S 13

Bowman’s capsule::

Bowman’s capsule: Items filtered out of the blood into the Bowman's capsule Glucose (but must be returned to the blood by active transport at the loop of Henle) Urea Salts Water Items that remain in the blood are RBCs WBCs Platelets Large chemicals like hormones 10/13/2016 SNEHA'S 14

Function of the Kidney::

Function of the Kidney : The principal function of the kidney is to filter blood in order to remove cellular waste products from the body. At any given time, 20 % of blood is in the kidneys. Humans can function with one kidney. If one ceases to work, the other increases in size to handle the workload. The kidney has other functions but it is usually associated with the excretion of cellular waste such as : 1) urea (a nitrogenous waste produced in the liver from the breakdown of protein. It is the main component of urine) ; 2) uric acid (usually produced from breakdown of DNA or RNA) and 3) creatinine (waste product of muscle action). 10/13/2016 SNEHA'S 15


All of these compounds have nitrogen as a major component. The kidneys are more than excretory organs. They are one of the major homeostatic organs of the body. They control water pH, secrete erythropoietin (a hormone that stimulates red blood cell production) and activate vitamin D production in the skin. That is why a doctor can tell so much from a urine sample . 10/13/2016 SNEHA'S 16

a few disorders of the excretory system: :

a few disorders of the excretory system: Obstructive disorders: kidney stones kidney cancer Renal failure - (kidney failure): UTIs - urinary tract infections, often caused by gram-negative bacteria cystitis- bladder infections urethritis-inflammation of the urethra pyelonephritis- inflammation of the kidneys 10/13/2016 SNEHA'S 17

kidney stones: :

kidney stones: Cause - metabolic disorder involving calcium, proteins and uric acid the build up of these substances into a large deposit (stone) Symptoms - irritation of the urinary tract, bleeding in the urinary tract, in cases with large stones there can be extreme pain as the stone(s) try to pass through the tract Treatments - removal by surgical means, breakdown of stones by either physical (ultrasound) or chemical means, dietary changes to reduce chances of stones   10/13/2016 SNEHA'S 18


THE EXCRETORY SYSTEM SPEAKS…. Roses are red Violets are blue I clean out the systems That's what I do Violets are blue Roses are red Without the excretory system We'd all be dead ! - by John H. 10/13/2016 SNEHA'S 19


THANK YOU ! 10/13/2016 SNEHA'S 20

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