Excretion Flashcards
What is excretion?
The removal of metabolic wastes, toxic substances, and substances in excess.
Give two examples of metabolic waste.
Urea and carbon dioxide (CO₂).
Name a toxic substance excreted by the body.
Alcohol.
Name two substances excreted in excess.
Salts and water.
What are the three main excretory organs?
Lungs, skin, and kidneys.
What do the lungs excrete?
Carbon dioxide (CO₂).
What does the skin excrete?
Sweat (water and salts).
What does the kidney excrete?
Urine (water, salts, and urea).
What is the main function of the urinary system?
To filter blood, remove waste, and regulate water balance.
Which blood vessel supplies the kidney with oxygenated blood>
Renal artery.
Which blood vessel carries filtered blood away from the kidney?
Renal vein.
What tube carries urine from the kidneys to the bladder?
Ureter.
What organ stores urine before excretion?
Bladder.
Through which structure does urine exit the body?
Urethra.
Where are nephrons located in the kidney?
In the cortex of the kidney.
What is the function of nephrons?
They filter blood and form urine.
Where does ultrafiltration occur?
In the glomerulus inside the Bowman’s capsule.
Why does ultrafiltration occur?
Due to high blood pressure in the glomerulus.
What substances are in the filtrate after ultrafiltration?
Water, urea, salts, glucose, and amino acids.
Why don’t plasma proteins and blood cells pass into the filtrate?
They are too large to pass through the filtration membrane.
Where does selective reabsorption take place?
In the proximal convoluted tubule.
What substances are reabsorbed into the blood?
Glucose and amino acids.
By what process are glucose and amino acids reabsorbed?
Active transport using energy.
What is osmoregulation?
The process by which the body controls plasma concentration.
What happens to plasma concentration when a person overheats?
Sweating causes plasma to become more concentrated.
Which organ detects changes in plasma concentration?
The hypothalamus.
What hormone is released to regulate water balance?
ADH (Antidiuretic Hormone).
Which gland releases ADH?
The pituitary gland.
How does ADH affect the kidney?
It increases the permeability of the collecting duct, allowing more water to be reabsorbed.
What happens to urine when ADH levels are high?
The volume of urine decreases, and its concentration increases.
