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