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PREPARED
BY:
Peñarubia, Patriz Lenn
Tinonas, Apple Gay
Raboy, Joanna Jane
Mendoza, Claire Anne
ELGA – COMPARATIVE ANATOMY LECTUREMAAM HAZEL TABO
VIDEO PRESENTATION
What is Excretory System?
• a passive biological system that removes nitrogenous wastes products of protein metabolism and many other harmful substances.
• Eliminates controlled amounts of water and salts.
• Maintains the internal environment within homeostasis.
Excretion• Excretion is the removal of the metabolic wastes of an organism. Wastes that are removed include carbon dioxide, water, salt, urea and uric acid. All excreted wastes travel at some time in the blood.
General Characteristics and Function of parts
1. Kidney
- primary adult excretory organs.
- primary function is the elimination of waste from the bloodstream by production of urine.
- are bean shaped organs which are present in each of the sides of the Vertebral column in the
abdominal cavity.
2.Lungs - removal of excess carbon dioxide.
3.Liver - produces urea and uric acid as a by-product of the breakdown of chemicals, poisons and toxin that enters the body.
4.Skin - removal of excess water, salt, urea and uric acid.
5. Large intestine - collects waste from throughout the body. It extracts any remaining usable water and then removes solid waste.
6. Eccrine - Like sweat glands, eccrine glands allow excess water to leave the body. They help the body to maintain temperature control.
Development and Evolution of kidneys
The embryonic mesoderm differentiates into a segmented dorsal epimere,small lateral mesomere, and unsegmentaed ventrolateral hypomere.
* Anterior mesomere -> nephrotomes
* Posterior mesomere ->
nephrogenic cord
At midpoint and posterior levels
* Kidney -> nephric ridge
Small coelomic spaces (nephrocoels) in nephrostomes are joined by peritoneal cavity to the general coelom or splanchocoel.
* Functional peritoneal canal and openings
= Neprostomes are ciliated
* In AMNIOTES, peritoneal canal fail to form
instead nephrocoels are formed within the
cord by cavitation process.
* Nephrocoels -> renal capsules• Nephric tubules -> outgrowths of the walls of
nephrocoels or solid masses of mesenchyme.
* Anterior tubules are first to develop and
its outer ends join to form nephric ducts.
* Nephric Duct extends to cloaca.
Development and Evolution of kidneys
Holonephros: The Ancestral Kidney
• Derived from entire mesomere.• The entire mass of nephrogenic tissue gives rise to this kidney, which is usually of simple form with a single tubule in each segment.
• Found in larvae of Hagfishes and Caecillians.
Pronephros: The Larval Kidney
• small segment of the excretory or renal system in many types of animals that lends itself to development of the kidney.
• is the earliest nephric stage in humans, and constitutes the mature kidney in most primitive vertebrates.
Other vertebrates
Hagfishes and Caecillians
Few nephrostomes about 1-12 pairs
Rarely more than 4 pairs
Nephrostomes
Pronephros: The Larval Kidney
• The first and last pairs of tubules degenerate and a giant corpuscle which is called glomus is formed by a partial or complete fusion.
• Pronephric tubules are simple and may become long and coiled.
Caecillians and Bony Fishes
Amphibians Some reptiles and Birds
Internal √
External √
Intermediate √
• Glomerulus also known as the Malpighian tuft, and is a series of intertwined capillary blood vessels within the nephron structure that is used to remove urine and toxins from the blood. (see table below)
• With ciliated neprostomes and open into anterior splanchnocoel -> pericardial cavity (adult)
• Modified into compacted glomus (head kidney) and remains functional in adult hagfishes and several bony fishes.
• May degenerate in Cartilaginous fishes, most amphibians and birds.
Function of Pronephros in different species:
Amphioxus
(Lancelets)
More advanced animals like
Mammals
Primitive fish such as
certain species of lamprey
Larval stages of other fish
Some
Amphi-
bians
Reptiles Birds
uses the pronephros as their main excretory organ.
vestigial organ that
develops first to aid in the development of
the larger mesonephros
renal organ of the embryo.
Have active pronephores
Have active pronep-hores
Have active pronep-hores
Exists but has
little or no
function
Exists but has little or no func-tion
Opisthonephros:Kidney of Anamiotes
• Anamniotes are an informal group comprising the fishes and the amphibians, the so-called "lower vertebrates", which lay their eggs in water.
• If all or most of mesomere posterior to the pronephores forms one kidney, that kidney is called opisthonephros.
• Typical to late larvae and adult amniotes.• Develops later in time than pronephros.• Opistonephric tubules are more coiled compared to pronephros and bulges more in coelom.
Opisthonephros:Kidney of Anamiotes
Hagfishes Other Vertebrates
Segmented and remains
Unsegmented
Opistonephric tubules are more coiled compared to pronephros and bulges more in coelom.
• Glomerulli are usually external.• Nephrostomes are present but for some retains
like Elasmobrachs, Primitive bony fishes and some amphibians but usually lost in adults.
• The mesonephros (Greek for "middle kidney") is one of three excretory organs that develop in vertebrates. It serves as the main excretory organ of aquatic vertebrates and as a temporary kidney in reptiles, birds, and mammals.
• Development is inversely proportional to the excretory efficiency of placenta.
Opisthonephros:Kidney of Anamiotes
Fishes Amphibians Reptiles Birds Mammals
forms the anterior
portion of the permanent kidneys
forms the anterior
portion of the permanent kidneys
atrophies and for the most
part disappears
rapidly as the permanent kidney
(metanephros) begins to develop
atrophies and for the most
part disappears
rapidly as the permanent kidney
(metanephros) begins to develop
atrophies and for the most
part disappears
rapidly as the permanent kidney
(metanephros) begins to develop
Metanephros:Kidney of Amniotes
• Amniotes are animals which posses amnions- sac like membranes that encases embryo.
• Most posterior and last to develop in both ontogeny and phylogeny.
• Permanent kidney in reptiles, birds, and mammals, developing by the 10th week in human embryos from the lower part of the Wolffian duct, and replacing the embryonic structure called the mesonephros. It consists of a compact, paired organ containing many nephrons; a ureter separate from the Wolffian duct leads from the metanephros to the bladder.
• Nephrons - formed by
successive generations.• Glomerulli – present• Nephrostomes – absent
Metanephros:Kidney of Amniotes
Reptiles Birds Mammals
Metenaphros
varies in shape
and lobulate
d.
Kidneys are fit into
hollow cavity.
Have collecting basin called renal pelvis
Primitive and small mammals
Marine Mammals
Kidneys are bean shaped simple and smooth
Rat lobate kidneys
Urinary System
• Urinary Bladder is a sac like hollow organ which provides temporary storage for urine.
Mammals Fishes Lampreys and
Teleo-costs
Amphi-bians
Reptiles Other Reptiles and Birds
Urine by
absorp-tion or secre-tion
Have small uri-nary blad-ders
Posterior ends of urinary ducts
serves as bladders
Has large
ventral outpoc- keting of the cloaca
Have iden-tical clocal bladder
Have no urinary bladders because they excrete a semisolid urine containing uric
acid.
• Ureters are a pair of tubes that carry urine from the kidneys to the urinary bladder. enters the side of cloaca and joins with fecal materials.
• Urethra is the tube through which urine passes from the bladder to the exterior of the body.
Urinary System
Is Urinary system the same with Excretory system?
• Basically the same thing dealing with different forms of waste material whereas the urinary or renal system removes waste from the blood and expels it via the bladder/urethra, while the excretory system forms the end of the digestive tract through which undigested material is expelled from the body.
REFERENCES• http://en.wikipedia.org/wiki/Excretory_system• https://whyevolutionistrue.wordpress.com/2012/02/08/
evidence-for-evolution-development-of-our-kidneys/• http://www.wisegeek.com/what-is-the-pronephros.htm• http://en.wikipedia.org/wiki/Anamniotes• http://www.embryo.chronolab.com/metanephros.htm• Comparative Anatomy of Vertebrates Compendium
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