Problem 75 - Objective Biology for NEET

Question

Heamolymph of cockroach consists of (a) Plasma (b) Haemocyte (c) Both (a) and (b) (d) None of these

Step-by-Step Solution

Answer

The hemolymph of cockroach consists of both Plasma and Haemocyte.

Step 1: Understanding Hemolymph

Before diving into the exercise, understand what 'Hemolymph' is. It is the fluid in the circulatory system of some animals including cockroaches.

Step 2: Recognizing Hemolymph Components

Know that the Hemolymph in cockroaches comprises both plasma and haemocytes. Plasma is the liquid part, while haemocytes are the cells similar to our white blood cells.

Step 3: Answering the Exercise

Based on the above information, option (c) , both plasma and haemocytes, is the correct answer. Therefore, hemolymph of cockroach consists of both Plasma and Haemocyte.

Key Concepts

Plasma in Hemolymph

In the fascinating world of cockroaches, hemolymph is the fluid that functions similarly to blood in vertebrates. Within hemolymph, plasma serves as the liquid component. Its essential role is to provide a medium for carrying nutrients, hormones, and waste products throughout the insect's body.
Unlike vertebrate blood, hemolymph plasma doesn't transport oxygen. Instead, it's responsible for distributing nutrients that support the cockroach's basic metabolic processes. Moreover, the plasma in hemolymph contains vital proteins and ions. These include enzymes necessary for various physiological processes. Additionally, plasma helps in the maintenance of the insect's overall immune response.

Haemocytes

Haemocytes are the cellular components of hemolymph, analogous to the white blood cells found in human blood. These cells play a crucial role in defending cockroaches against infections and injuries. In cockroaches, haemocytes fulfill several functions such as:

• Phagocytosis: Engulfing and digesting foreign particles and microorganisms.
• Clot formation: Helping to prevent the loss of hemolymph at wound sites, much like clotting in human blood.
• Encapsulation: Forming layers around larger foreign bodies that can't be quickly consumed or destroyed.

These specialized cells ensure the cockroach's immune system remains effective against diverse challenges.

Insect Circulatory System

The insect circulatory system, including that of cockroaches, is an open system. Unlike humans, insects do not have closed blood vessels. Instead, hemolymph wholly surrounds the internal organs, bathing them directly. Hemolymph is circulated by a structure known as the dorsal vessel. This structure includes a heart situated dorsally in the abdomen.
The dorsal vessel propels the hemolymph through the insect's body cavity, a process that facilitates the distribution of nutrients and removal of waste.
This system's simplicity supports the cockroach's survival in various environments. Because it bathes the organs directly, it allows for efficient nutrient exchange and immune response. The open nature also means that cockroaches can withstand severe damage that might be fatal for creatures with closed circulatory systems. This adaptability is one of their keys to resilience.