17 terms

7th Grade Science - Excretory System

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Excretion
Process of getting rid of wastes from the body. If the body did not get rid of wastes, the body would acquire illness much easier. The body eliminates waste by turning into Urea, a chemical that comes from the breakdown of proteins.
Urea
a chemical that comes from the breakdown of proteins.
Kidney
A major organ of the excretory system which removes urea and other wastes from the blood.
Urine
A watery fluid produced by the kidneys, that contains urea and other waters.
Ureter
A narrow tube that carries urine from one of the kidneys to the urinary bladder.
Urinary Bladder
A sack-like muscular organ that stores urine until it is eliminated from the body.
Urethra
A small tube through which urine flows from the body.
Nephron
Small filtering structure found in the kidneys that remove wastes from blood and produces urine.
What does the excretory system do? How does it help your body?
The excretory system helps get rid of wastes in your body. Excretion helps maintain homeostasis and without excretion, harmful toxins would house themselves in your body and cause illness.
Name the structures of the excretory system and their functions?
Four Structures are:
-The Kidney - major organ that removes urea and other wastes from the blood
-The Ureter - a narrow tube that carries urine from one of the kidneys to the urinary bladder
-The Urinary Bladder - a saclike muscular organ that stores urine until it is eliminated from the body
-The Urethra - A small tube through which urine flows from the body
How does the body filter waste?
The nephrons filter waste in stages. First, both wastes and needed materials, such as glucose, are filtered out of the blood. Then, much of the needed material is returned to the blood, and the wastes are eliminated from the body.
How is urine formed?
There are three steps for urine formation: filtration, reabsorption and secretion. The average person filters 43 gallons of water and other chemicals per day, but 99% gets reabsorbed by the body. During reabsorption, substances move from the renal tubes back into the blood capillaries. In the last step, the body converts the waste into urine, which eventually leaves the body
What is the role of excretion in maintaining homeostasis?
Excretion helps maintain Homeostasis by excreting wastes from the body, which eliminates harmful toxins housing themselves in your body, which would increase the chance of getting an illness.
How does the kidney's help maintain homeostasis?
Kidney removes urea and other wastes from the blood
What is excretion through the lungs?
When you exhale, carbon dioxide and some water are removed from the body by the lungs.
What is excretion through the skin?
Sweat glands in the skin also serve an excretory function because water and urea are excreted in perspiration.
What role does the liver play in excretion?
The liver breaks down some large wastes before they can be excreted. For example, urea, which comes from the breakdown of proteins, is produced by the liver. The liver also converts part of the hemoglobin molecule from old blood cells into substances such as bile.