What is excretion?
The biological process by which organisms remove waste products or harmful substances from their bodies.
Why is excretion important?
It prevents waste accumulation, maintains water and salt balance, and eliminates toxic substances.
Name the main components of the urinary system.
Kidneys, ureters, bladder, and urethra.
What are the two main regions of the kidney?
Cortex and medulla.
What is the function of the renal artery?
It carries blood into the kidney for filtration.
What is a nephron?
The functional unit of the kidney that filters blood and forms urine.
What happens in Bowman’s capsule?
It receives filtered blood from the glomerulus.
What is the role of Henle’s loop?
It aids in water and salt reabsorption.
What controls water reabsorption in the distal tubule?
Antidiuretic hormone (ADH).
What are the three steps in urine formation?
Ultrafiltration, selective reabsorption, and hormonal secretion.
What excretory products are removed by the lungs?
Carbon dioxide and water vapor.
How does the liver contribute to excretion?
It processes toxins and excretes them into bile.
What substances does the skin excrete?
Water, salts, and urea through sweat glands.
How do plants excrete waste?
By releasing oxygen and water through stomata and storing substances like latex or gum.
What is the excretory organ in earthworms?
Nephridia.
How do nephridia in earthworms function?
They collect and process waste from coelomic fluid, expelling it through pores.
What are flame cells?
Specialized cells in flatworms that help in excretion by creating a flickering motion.
How do flatworms eliminate waste?
Through longitudinal canals that end in flame cells and excretory pores.
What is the role of the bladder in the urinary system?
To store urine until it is excreted through the urethra.
How does the medulla contribute to kidney function?
It contains tubules and pyramids that facilitate urine concentration and transport to the pelvis.
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