what does the excretory system do?

Answer 1

Nitrogenous Wastes: are by products of the breakdown of proteins. Amino acids must be deaminated if they are not going to be used in protein synthesis. The NH2 end group is removed and a Hydrogen is added to form ammonia. Animals will dilute this with water and excrete it into the environment. Land animals must change it into the substance urea. This change occurs in the liver. Birds, reptiles, and insects change ammonia into uric acid. Uric acid requires a tremendous amount of energy to produce.

Osmoregulation in Different environments:

The removal of nitrogenous waste from body fluids is tied to osmoregulation, the balance between salts and water.

Freshwater Bony fish:
Do not drink water.
Osmotic uptake of water occurs through the gills,
salt is taken up by active transport through the gills,
and they have hypotonic urine.

Marine bony fish:
Drink salt water,
salt output is through the gills using active transport,
ammonia and osmotic water loss also occurs through the gills.
Their urine is isotonic.

Sharks:
Drink no water,
urea retained,
water is lost from the body by osmosis through the gills.

Marine birds:
Salt water is excreted through nasal glands,
they drink salt water,
and rid their body of concentrated urine via cloaca.

Whales: drink water and have concentrated urine.

How do excretory organs work?

a). collects fluids from somewhere in the body.
b). modifies the fluids by reabsorbing substances the body needs.
c). provides a way to expel the excretory product from the body.

These organs expend metabolic energy to carry out these functions. The human kidney makes up .05% of the bodies weight and uses 7.2% of the oxygen it consumes.

The Human Kidney:
Every vertebrate has a pair of kidneys.
Their functional units are called nephrons. The kidney contains more than a million nephrons, which collect fluid from filtered blood.
The renal arteries and renal veins carry blood to and from the kidney.
The collected waste material leaves the kidney via the ureter and is stored in the urinary bladder; it is then expelled from the body through the urethra.
The kidney filters 1600 liters of blood per day, producing 1 liter of urine.



Function of the Nephrons: Let's follow the process of urine formation in a nephron.

The nephron's cup shaped Bowmans Capsule surrounds a knot of blood capillaries called the glomerulus. Much of the bloods fluid filters into the glomerulus due to pressure from the circulatory system. Left behind are large proteins and whole cells, which are too large to fit through. This filtrate is then passed through the nephron tubule, which has 4 main parts ( proximal convoluted tubule, loop of Henle, distal convoluted tubule, and the collecting duct).
In the proximal convoluted tubule, a considerable amount of resorbtion occurs. Small proteins, glucose, and ions are returned to the blood by active transport. Negatively charged ions follow passively, followed by the osmosis of water. About 75% of the filtrate is returned in this section of the nephron.
The loop of Henle, lie in the medulla of the kidney, the other parts of the nephron lie outside of the medulla in the cortex. Salt is actively transported out of the filtrate, and since this area impermeable to water, water cannot follow the ions out here.
The distal convoluted tubule, urine is then passed through here to the collecting duct where it is concentrated due to its permeability to water. It leaves the collecting duct into the pelvis of the kidney, which leads to the ureter and the bladder where it is stored.

Answer 2

Cells produce water and carbon dioxide as by-products of metabolic breakdown of sugars, fats, and proteins. Chemical groups such as nitrogen, sulfur, and phosphorous must be stripped, from the large molecules to which they were formerly attached, as part of preparing them for energy conversion. The continuous production of metabolic wastes establishes a steep concentration gradient across the plasma membrane, causing wastes to diffuse out of cells and into the extracellular fluid.

Single-celled organisms have most of their wastes diffuse out into the outside environment. Multicellular organisms, and animals in particular, must have a specialized organ system to concentrate and remove wastes from the interstitial fluid into the blood capillaries and eventually deposit that material at a collection point for removal entirely from the body.

Excretory systems regulate the chemical composition of body fluids by removing metabolic wastes and retaining the proper amounts of water, salts, and nutrients. Components of this system in vertebrates include the kidneys, liver, lungs, and skin.

Not all animals use the same routes or excrete their wastes the same way humans do. Excretion applies to metabolic waste products that cross a plasma membrane. Elimination is the removal of feces.

Excretory System Functions
1) Collect water and filter body fluids.
2) Remove and concentrate waste products from body fluids and return other substances to body fluids as necessary for homeostasis.
3) Eliminate excretory products from the body

Answer 3

the excretory system processes and gets rid of waste materials from the body

Answer 4

the excretory system excrete waste product from body

Answer 5

getting rid of waste and poisonous substances from the body by:
1 the skin by sweating
2 the kidney by ultra filtration,selective reabsorption and osmo regulation (waste is then sent out of the body as pee)
3 the liver gets rid fo bile bile pigments from haemoglobin of blood cells
4 the lungs get rid of carbondioxide by breathing.
The poisonous substances include urea from protein,carbondioxide from respiration,bile pigments from haemoglobin of blood cells and a whole lot more

Answer 6

It gets rid of the metabolic wastes from the body.

Answer 7

thats poop and pee, why dont you study something, it gets rid of poisons in your body