Structure and Function of Excretory Organs in Humans Grasshoppers and Worms
The excretory system is pivotal in maintaining the internal environment of an organism by removing metabolic waste. This article delves into the structure and function of excretory organs in humans, grasshoppers, and worms.
1. Humans
a. Kidneys
Structure: Bean-shaped organs located on either side of the spine, filled with nephrons.
Function: Filters blood, removes waste and excess substances, and forms urine.
b. Ureters
Structure: Tubes leading from the kidneys to the urinary bladder.
Function: Transport urine from kidneys to the bladder.
c. Urinary Bladder
Structure: Muscular sac situated in the pelvic region.
Function: Stores urine until it’s expelled.
d. Urethra
Structure: Tube leading from the bladder to the external body.
Function: Discharges urine from the body.
2. Grasshoppers (Belalang)
a. Malpighian Tubules
Structure: Fine, hair-like tubules found at the junction of the midgut and hindgut.
Function: Extract waste from the hemolymph (grasshopper’s blood equivalent) and convert it into uric acid, which is excreted with feces.
b. Hindgut
Structure: The posterior section of the digestive tract.
Function: Reabsorbs water from the waste, forming a semi-solid excrement.
3. Worms (Cacing)
For the purpose of this article, we’ll focus on the common earthworm:
a. Nephridia
Structure: Tubular structures present in almost every segment of the earthworm.
Function: Filters the coelomic fluid, removing metabolic waste. Excretes waste through tiny pores on the worm’s surface.
Conclusion
Though humans, grasshoppers, and earthworms differ significantly in their anatomy and physiology, each has evolved a specialized excretory system tailored to their needs. These systems ensure that metabolic wastes are efficiently removed, allowing these organisms to maintain internal equilibrium and thrive in their respective environments.
QUESTIONS AND ANSWERS
1. Question: What is the primary excretory organ in humans?
Answer: The kidney.
2. Question: How do grasshoppers primarily eliminate waste?
Answer: Through Malpighian tubules, which convert waste into uric acid that’s excreted with feces.
3. Question: Which organ in earthworms performs a similar excretory function as kidneys in humans?
Answer: Nephridia.
4. Question: What substance transports waste in grasshoppers?
Answer: Hemolymph.
5. Question: Where does urine formation take place in humans?
Answer: In the nephrons of the kidneys.
6. Question: What is the role of the urethra in the human excretory system?
Answer: It discharges urine from the body.
7. Question: Which part of the grasshopper’s digestive system is responsible for water reabsorption?
Answer: The hindgut.
8. Question: How do earthworms excrete waste from nephridia?
Answer: Through tiny pores on their surface.
9. Question: What is the function of the urinary bladder in humans?
Answer: To store urine until it’s expelled.
10. Question: Why do grasshoppers produce uric acid as their primary waste product?
Answer: Uric acid is less toxic and conserves water as it is excreted as a semi-solid with feces.
11. Question: What is the structure in earthworms that filters the coelomic fluid?
Answer: Nephridia.
12. Question: How are the ureters related to the excretory function in humans?
Answer: They transport urine from the kidneys to the urinary bladder.
13. Question: Where are Malpighian tubules located in a grasshopper?
Answer: At the junction of the midgut and hindgut.
14. Question: In which segment of the earthworm are nephridia typically found?
Answer: In almost every segment.
15. Question: How do humans primarily excrete nitrogenous waste?
Answer: As urea in urine.
16. Question: Why is the conversion of ammonia to urea crucial in the human excretory process?
Answer: Ammonia is toxic, while urea is less harmful and can be efficiently excreted.
17. Question: What would be the consequence if the hindgut of a grasshopper didn’t reabsorb water efficiently?
Answer: The grasshopper would lose excessive water, leading to dehydration.
18. Question: How do nephridia in earthworms contribute to maintaining their internal environment?
Answer: By filtering and removing metabolic waste from the coelomic fluid.
19. Question: Why are Malpighian tubules essential for the survival of grasshoppers in arid environments?
Answer: They excrete waste in the form of uric acid, conserving water.
20. Question: How do the structures and functions of excretory systems differ between species?
Answer: Excretory systems are tailored to the metabolic needs and environments of each species. For instance, humans use kidneys to filter blood, grasshoppers use Malpighian tubules for hemolymph, and earthworms use nephridia for coelomic fluid.
