Excretory System
Study of Malpighian tubules as the primary excretory organs, along with the roles of fat body, nephrocytes, and uricose glands.
What is Excretory System?
Slender, blind-ended tubes extending from the gut into the haemocoel of insects, serving as the primary excretory organs.
Key points
- Identify the principal excretory organs in a cockroach.
- Describe the structure and function of Malpighian tubules.
- Explain the process of waste filtration and excretion.
- Recognize the roles of accessory excretory structures.
Common exam trap
Confusing the function of Malpighian tubules with digestive functions.
Definitions
- Term
Malpighian tubules
- Meaning
Slender, blind-ended tubes extending from the gut into the haemocoel of insects, serving as the primary excretory organs.
- Term
Haemolymph
- Meaning
The circulatory fluid of arthropods, analogous to blood, which bathes the organs directly.
- Term
Uricotelic
- Meaning
An animal that excretes nitrogenous waste primarily in the form of uric acid.
- Term
Nephrocytes
- Meaning
Specialized cells, often found in the fat body, that phagocytose and store waste products.
Learning objectives
Identify the principal excretory organs in a cockroach.
Describe the structure and function of Malpighian tubules.
Explain the process of waste filtration and excretion.
Recognize the roles of accessory excretory structures.
Understand the significance of uricotelic excretion in cockroaches.
Prerequisites
Basic understanding of insect anatomy.
Knowledge of digestive system of cockroach.
Concept of haemolymph and its composition.
Understanding of osmoregulation.
Common mistakes
Confusing the function of Malpighian tubules with digestive functions.
Overlooking the role of the hindgut in reabsorption.
Not recognizing the accessory roles of the fat body and nephrocytes.
Assuming ammonia is the primary excretory product (like in aquatic animals).
Keywords
Excretory system
Cockroach
Malpighian tubules
Uric acid
Haemolymph
Hindgut
Fat body
Nephrocytes
Uricotelic
Osmo-regulation
Practice preview
What is the role of the rectal pads in the cockroach's excretory system?…
medium
What is the main nitrogenous waste product excreted by cockroaches?…
easy
Where are Malpighian tubules located in the cockroach's digestive system?…
easy