Excretion in earthworms occurs through a specialized tubular system known as metanephridia, which is present in each segment of their body. Each metanephridium consists of a nephrostome that collects coelomic fluid, which is then filtered as it passes through the tubule. During this process, essential salts and water are reabsorbed into the bloodstream, while nitrogenous wastes are excreted as urine. This efficient system allows earthworms to regulate their internal environment and eliminate toxic substances effectively, contributing to their survival in moist soil habitats
What is the primary excretory structure in earthworms?
The primary excretory structure in earthworms is the metanephridium, which is present in each segment of their body
How does the metanephridium function in earthworms?
Each metanephridium consists of a nephrostome that collects coelomic fluid, which is then filtered as it passes through the tubule, allowing for the reabsorption of essential salts and water while excreting nitrogenous wastes
What type of nitrogenous waste do earthworms primarily excrete?
Earthworms primarily excrete nitrogenous waste in the form of urea, which is less toxic and conserves water compared to ammonia
How do earthworms regulate their internal environment through excretion?
Earthworms regulate their internal environment by filtering coelomic fluid through metanephridia, reabsorbing necessary substances, and excreting waste products, thus maintaining homeostasis
What is the role of the nephrostome in the excretory system of earthworms?
The nephrostome is the ciliated opening of the metanephridium that collects coelomic fluid for filtration and excretion
What is the primary excretory structure in earthworms?
a) Nephron
b) Malpighian tubule
c) Metanephridium
d) Protonephridium
Answer: c) Metanephridium
How many pairs of metanephridia are found in each segment of an earthworm?
a) One
b) Two
c) Three
d) Four
Answer: b) Two
What is the function of the nephrostome in earthworms?
a) To excrete solid waste
b) To collect coelomic fluid
c) To absorb nutrients
d) To filter blood
Answer: b) To collect coelomic fluid
Which nitrogenous waste do earthworms primarily excrete?
a) Ammonia
b) Urea
c) Uric acid
d) Creatinine
Answer: b) Urea
What process occurs as coelomic fluid passes through the metanephridia?
a) Filtration and absorption
b) Digestion
c) Respiration
d) Circulation
Answer: a) Filtration and absorption