Excretory System

 EXCRETION & EXCRETORY SYSTEM

        Living organisms eat, potable in addition to exercise.  During these processes,     they accumulate a lot of toxic waste materials products which if unremoved,    may constitute a lot of danger in addition to chaos inward the organism.

        Excretion is thus the removal of waste materials products of metabolism from the trunk of an organism.  These waste materials products are strictly from metabolism in addition to non digestion.  The tissues in addition to organs involved inward the elimination of metabolic waste materials are called the excretory system.

        Why Organisms Need To Excrete

          Simple organisms similar amoeba are inward straight contact with their fluid      habitats.  Simple diffusion is plenty to allow waste materials products to        diffuse into the surrounding environment.  Liquid waste materials in addition to salts yesteryear a elementary exocylosis.  The amoeba tin travel rid of these wastes.  This      is done when the contractile vacuole fuses with the jail cellphone membrane         in addition to exerts osmotic pressure level on the jail cellphone membrane.

        This causes the vacuole to outburst opened upwardly in addition to releases the waste materials outside.  But inward higher organisms with increase trunk size in addition to numerous numbers of cells, metabolic in addition to physiological activities increase thereby causing waste materials production to build.  If unremoved or allowed to linger, they

        1.     Become toxic to the cells in addition to tissues in addition to tin kill or harm             them

        2.     Disrupt the internal trunk residual of the organism causing the            organism to endure sick

        3.     Become poisonous to the organism if allowed to accumulate

        4.     Interrupt normal metabolic activities yesteryear feedback mechanism

       

        Excretory Structures And Products

          Apart from diffusion inward unicellular organisms, higher organisms purpose     other structures beside contractile vacuole to excrete.  Different        products too arise from the metabolic processes equally shown below:

Organism	Excretory Structure	Excretory Product
Protozoa (Amoeba, Paramecium)	Contractile Vacuole	CO2, NH3, H2O
Flat worms	Flame Cells	CO2, NH3, H2O
Insects	Malpighian tubules	H2O, CO2, in addition to Uric Acid
Earthworm	Nephridium	Nitrogenous waste, urea & CO2
Crustaceans	Green gland	H2o, Urea, NH3Salts, CO2
Mammals	-      Skin -      Lungs -      Kidney -      Liver	Sweat (Urea, Salts, Water) CO2 & Water Vapour    Urine (Urea, Salts,Water Hormones                    Bile, Salts, Water
Plants	-      Stomata & Lenticels -      Bark of Trees	H2O, CO2 & O2 Tannins, gum, crystals, antholyanin, oils resins, latex, quinine, cocain etc.

CD 2:  STRUCTURE & MECHANISMS: PERIOD 2

Flame Cells:

Diagram Of The Flame Cell

Diagram Of The Malpighian Tubule

Diagram Of The Nephridium Of An Earthworm

Mammalian Excretory System (Urinary System):

The kidney is the major organ for excretion inward mammals.

Diagram Of The Urinary System Of Mammals

         Diagram Of The Longitudinal Section Of The Mammalian Kidney

Diagram Of The Nephron

    MECHANISMS

Flat Worms:  (Flame Cell)

The open fire jail cellphone is a funnel shaped construction establish inward each abdominal segment.   It has a lumen containing a collection of flagellum. The cytoplasmic processes projection inward every direction patch a nucleus is introduce inward it to command its activities.  The jail cellphone lumen or cytoplasm has a lot of mitochondria that generate unloose energy inward the beating activity of the flagella.  By diffusion, H2O ammonia in addition to CO₂ move into the jail cellphone lumen where the beating activity of the flagella propels them to the tubules where they are removed to the exteriors.

Insects: (Malpighian tubules)

These organs are establish floating inside the abdominal in addition to thoracic segments. They consist of distal ends in addition to proximal ends which opens into the hindgut.

Waste products collect inward the distal terminate of the tubule yesteryear diffusion.  They motility downwards the gut in addition to equally they pass, H2O is reabsorbed patch the liquid waste materials is converted into a corporation waste materials called une acid.  Rectal glands introduce inward the hindgut aid to reabsorb to a greater extent than H2O leaving the waste materials to a greater extent than concentrated (almost dry).

Earthworm:  (Nephridium)

Apart from the kickoff 2 in addition to the final segment, each segment contains a couplet of nephridia.  Each nephridium has a funnel called Nephrostome, a tubule divided into iv parts (narrow aliated, middle aliated, broad nonaliated in addition to broad muscular parts).  Each nephridia terminates inward a nephridiophere.  The nephridium is surrounded yesteryear a network of capillaries.  The waste materials production mainly urea in addition to guanin are extracted from the blood capillaries surrounding the nephridia.  This waste materials production is pan into the funnel in addition to downwards the tube.      Water in addition to salts amongst with other substances are reabsorbed through the wall of the tube.  The unreabsorbed substances collected inward the muscular underground in addition to ejected exterior when the underground releases.

Man: (Kidney)

The 2 bilateral kidneys take waste materials products yesteryear iii principal processes namely;

-      Ultrafilration

-      Tubular Reabsorption

-      Hormonal Secretion

These iii processes occur at strategic zones of the renal tubule.

Ultrafilration:  blood from the renal artery comes with a real high pressure level which materials of modest molecular size through the selective pores of the renal corpusele (Bowmen’s capsule & glomerulus).  As a lawsuit materials or substances ranging from water, salt, hormones, urea.  Other nitrogenous waste materials products are forced into the funnel downwards the tubule.  This is called glomerular filtrate.

Reabsorption:  This element of the filtrate reaches the proximal convulated tubule where depending on the osmotic slope of the blood activates the release of ADH from the posterior pituitary gland.  ADH mediates the opening of the pores in addition to channels inward the tubule allowing H2O in addition to other useful products that may convey escaped into the filtrate to endure reabsorbed with the blood.  Further reabsorption of H₂O in addition to salts (Nacl) occur at the thick ascending loop of 

Hormonal Secretion:  By the fourth dimension the reabsorption processes is over, the filtrate would convey been in addition to then diluted in addition to devoid of salts.  So the blood forthwith may endure in addition to then concentrated with salts.  The trunk is activated to secrete about salts into the distal tubule using about minerals corticoid (Aldesterine from the Adrenal cortese.  The fluid in addition to then passed into the bladder via the collecting tubules is slightly tabular array salt in addition to forthwith concentrated with urea.  This is called urine. 

      PROJECT: WHAT IS KIDNEY DIALYSIS

   WHAT ARE THE MAJOR CHALLENGES FACING KIDNEY TRANSPLANT.