excreation
the process by which animals rid themselves of waste products and of the
nitrogenous by-products of metabolism. Through excretion organisms
control osmotic pressure—the balance between inorganic ions and water—and
maintain acid-base balance. The process thus promotes homeostasis, the constancy of the organism’s
internal environment.
nitrogenous by-products of metabolism. Through excretion organisms
control osmotic pressure—the balance between inorganic ions and water—and
maintain acid-base balance. The process thus promotes homeostasis, the constancy of the organism’s
internal environment.
protist
Unicellular protist first of all have a very reduced size. This means that
they do not require any special organ of excretion as in multicellular animals.
Therefore excretion is by simple diffusion across the cell membrane. For
example, excretory gases leave the cell via the membrane likewise to other
metabolic waste.
Annelid Worms
One such elaborate system is the excretory system which
consists of small,
coiled tubes with walls that are glandular and richly
supplied with blood
vessels. These coiled tubular excretory structures are
known as nephridia. They
occur in all the segments of the body starting from the third segment downwards.
Based on their location three kinds of
nephridia can be distinguished.
consists of small,
coiled tubes with walls that are glandular and richly
supplied with blood
vessels. These coiled tubular excretory structures are
known as nephridia. They
occur in all the segments of the body starting from the third segment downwards.
Based on their location three kinds of
nephridia can be distinguished.
insects
The diverse excretory systems of insects exhibit several features that appear
unusual when comparisons are made with the mammalian kidney. Secretion by the
Malpighian tubules of a fluid that is unlike the blood in composition,
substitutes for glomerular filtration. Various reabsorptive functions, such as
volume reduction, regulation of individual electrolytes, adjustment of osmotic
concentration and pH regulation, which are associated with distinct renal
segments in the mammalian kidney, all occur simultaneously in the rectum of
terrestrial insects.
unusual when comparisons are made with the mammalian kidney. Secretion by the
Malpighian tubules of a fluid that is unlike the blood in composition,
substitutes for glomerular filtration. Various reabsorptive functions, such as
volume reduction, regulation of individual electrolytes, adjustment of osmotic
concentration and pH regulation, which are associated with distinct renal
segments in the mammalian kidney, all occur simultaneously in the rectum of
terrestrial insects.
Amphibians
Direct evidence for the occurrence of filtration at the glomerulus was
first provided by experiments on the amphibian kidney. Although amphibians are
formally given the status of terrestrial animals, they are poorly adapted to
life on land. They excrete nitrogen in the form of urea and cannot produce urine
more concentrated than the blood.
first provided by experiments on the amphibian kidney. Although amphibians are
formally given the status of terrestrial animals, they are poorly adapted to
life on land. They excrete nitrogen in the form of urea and cannot produce urine
more concentrated than the blood.
mammals
The mammalian kidney is a compact organ with two distinct regions: cortex and medulla. The functional unit of the kidney is the
nephron. Each nephron is a tubular structure
consisting of four regions.
nephron. Each nephron is a tubular structure
consisting of four regions.
nonvascular plants
Non-vascular are plants without a vascular system. Therefore many plants of the
kind possess tissues needed for the internal transport of water. Thus the
excreted nutrients are used as a kind of storage because they can't excrete
waste to the surrounding.
kind possess tissues needed for the internal transport of water. Thus the
excreted nutrients are used as a kind of storage because they can't excrete
waste to the surrounding.
gymnosperm
Gymnosperms are said to excrete waste through photosynthesis. They use
their roots to excrete waste during transport. They release oxygen and other
non-essential elements.
their roots to excrete waste during transport. They release oxygen and other
non-essential elements.
angiosperm
is produced during photosynthesis in such large quantities that most of it
is released to the atmosphere to the benefit of us nonphotosynthetic organisms.
Plant use a little oxygen for respiratory processes just like we do but most of
what they produce is a waste product.
is released to the atmosphere to the benefit of us nonphotosynthetic organisms.
Plant use a little oxygen for respiratory processes just like we do but most of
what they produce is a waste product.