Excretion in various invertebrates and vertebrates is dealt as per the PG syllabus prescribed by Vijayanagara Sri Krishnadevaraya University Ballari. It is useful for the PG students studying animal physiology as the core subject under zoology. It gives a overall picture of excretion to the teacher who is teaching animal physiology to the collegiate and university levels.
The video lectures of Biology in easy way are available on youtube channel.
https://youtu.be/Qg_SXsAwMmA
Basic Information about Osmoregulation in Animals
Malpighian tubules and Coxal Glands in Arachnidsنوشی نایاب
Malpighian Tubules. Malpighian tubules remove nitrogenous wastes
(uric acid) from the hemocoel. Various ions are actively transported
across the outer membrane of the tubule. Water follows these ions
into the tubule and carries amino acids, sugars, and some nitrogenous
wastes along passively. Some water, ions, and organic compounds are
reabsorbed in the basal portion of the Malpighian tubules and the
hindgut; the rest are reabsorbed in the rectum. Uric acid moves into
the hindgut and is excreted in the feces.
Coxal Glands in Arachnids. ( a ) The gut and excretory systems of a
spider. The stercoral pocket is a diverticulum off the hindgut that stores
waste prior to waste elimination. ( b ) Coxal gland muscles attach to the
thin saccular fi ltration membrane. These muscles promote fi ltration and
fl uid fl ow (black arrows) by contracting and relaxing along the tubular
duct. Water and solutes are reabsorbed along the tubular duct.
Excretion in various invertebrates and vertebrates is dealt as per the PG syllabus prescribed by Vijayanagara Sri Krishnadevaraya University Ballari. It is useful for the PG students studying animal physiology as the core subject under zoology. It gives a overall picture of excretion to the teacher who is teaching animal physiology to the collegiate and university levels.
The video lectures of Biology in easy way are available on youtube channel.
https://youtu.be/Qg_SXsAwMmA
Basic Information about Osmoregulation in Animals
Malpighian tubules and Coxal Glands in Arachnidsنوشی نایاب
Malpighian Tubules. Malpighian tubules remove nitrogenous wastes
(uric acid) from the hemocoel. Various ions are actively transported
across the outer membrane of the tubule. Water follows these ions
into the tubule and carries amino acids, sugars, and some nitrogenous
wastes along passively. Some water, ions, and organic compounds are
reabsorbed in the basal portion of the Malpighian tubules and the
hindgut; the rest are reabsorbed in the rectum. Uric acid moves into
the hindgut and is excreted in the feces.
Coxal Glands in Arachnids. ( a ) The gut and excretory systems of a
spider. The stercoral pocket is a diverticulum off the hindgut that stores
waste prior to waste elimination. ( b ) Coxal gland muscles attach to the
thin saccular fi ltration membrane. These muscles promote fi ltration and
fl uid fl ow (black arrows) by contracting and relaxing along the tubular
duct. Water and solutes are reabsorbed along the tubular duct.
osmoregulation in invertebrates- it is a processes by which any organisms maintains the fluid and salt balance of its body, which is important for proper functioning of organs .
Kidney (STRUCTURE AND FUNCTIONS) (: The Guyton and Hall physiology)Maryam Fida
STRUCTURE AND FUNCTIONS OF KIDNEY
There are two kidneys in body , Rt & Lt, lying on post abdominal wall, outside peritoneal cavity.
There weight is aprx. 150 Gm and size is clenched fist.
On medial side, there is a region called hilum through which pass blood & lymphatic vessels, nerve fibers and ureterKidney is surrounded by a protective fibrous capsule.
Each kidney has two major zones, outer thick known as cortex and part known as medulla.
Medulla is divided into multiple cone shaped tissue masses called renal pyramid.
The base of pyramid begins at junction of cortex & medulla and terminates in papilla which projects into space of renal pelvis.
Renal pelvis is funnel shaped continuation of upper end of ureter.
1- Excretion of metabolic waste products such as urea, creatinine, uric acid, Bilirubin, hormones & drugs.
2-. ELIMINATE HARMFUL FOREIGN COMPOUNDS.
Such as toxins, drugs, heavy metals, pesticides.
3- Regulation of water & electrolyte balance to maintain normal homeostasis of body by re-absorption and adjustment of rate of excretion of various substances.
4- Regulation of Arterial Pressure.
*Long term regulation by excreting variable amounts of water and sodium
and
*short term by secreting vaso-active substance (renin).
1. Chapter 44 ~ Regulating the Internal Environment
• KEY POINT! Homeostasis is the maintenance of a constant internal
environment
I.Regulation of Body Temperature
• A. Thermoregulation-Maintenance of body temperature.
• Ectothermic: body heat obtained from the environment
• Endothermic: high metabolic rate generates high body heat
4 physical processes account for heat gain or loss:
• 1.Conduction~transfer of heat between molecules of body and environment
• 2.Convection~transfer of heat as water/air move across body surface
• 3.Radiation~transfer of heat produced by organisms
• 4.Evaporation~loss of heat from liquid to gas
D.Regulation during environmental extremes
• 1. Torpor~ low activity; decrease in metabolic rate
– a.Hibernation long term or winter torpor (winter cold and food scarcity);
bears, squirrels
– B. Estivation short term or summer torpor (high temperatures and water
scarcity); fish, amphibians, reptiles
• II. Osmoregulation and waste disposal
• A. Osmoregulation is the management of the body’s water content and solute
composition, which is critical to survival and homeostasis.
2. B. Nitrogenous waste management is critical…
• 1.Nitrogenous wastes form from the metabolism of proteins and nucleic acids-very
toxic
– Ammonia: formed and removed by most aquatic animals,fish
– Urea: mammals, most amphibians, sharks, some fish
– Uric acid: allows for little water loss-very concentrated form of liquid
waste found in birds, insects, many reptiles, land snails
• C. Methods of osmoregulation
• 1. Osmoconformer: no active adjustment of internal osmolarity (marine animals);
isoosmotic to environment (same)
• 2. Osmoregulator: adjust internal osmolarity (freshwater, marine, terrestrial)
Freshwater fishes (hyperosmotic)- gains water, loses salt; excretes large amounts
of dilute urine.
3.Water balance is critical on Land
• 1.Dessication is deadly (12% drop for human=death)
• 2.Adaptations to retain water:
– Cuticle, shells, exoskeletons, nocturnal behaviors
III. Excretory Systems
• A.Most excretory systems produce urine in 2 steps:
3. • Filtration (nonselective)
– Reabsorption (secretion of solutes)
• B.The Kidney is our organ of excretion
• 1.Renal artery/vein: kidney • 5.Renal cortex (outer region)
blood flow
• 6.Renal medulla (inner region)
• 2.Ureter: urine excretory duct
• 7.Nephron: functional unit of
• 3.Urinary bladder: urine storage kidney
• 4.Urethra: urine elimination
tube
Nephron Function, I Nephron Function, III
•Proximal tubule: secretion and •Collecting duct: reabsorbs water, salt,
reabsorption some urea
Nephron Function, II
•Loop of Henle: reabsorption of water
and salt
•Distal tubule:secretion and reabsorption
Kidney regulation: hormones
• Antidiuretic hormone (ADH) ~ most important hormone for osmoregulation!)
brings H2O back to body; inhibited by alcohol and coffee
