Cockroach MCQ Test - Zoology, Class 11 - Class 11 MCQ

Answer:
The completely developed endoskeleton and exoskeleton are present in the thoracic region of a cockroach. Here is a detailed explanation:
1. Introduction:
- Cockroaches are insects that belong to the class Insecta and the order Blattodea.
- They have a segmented body and a hard exoskeleton that provides protection and support.
2. Endoskeleton:
- The endoskeleton is the internal skeleton of an organism.
- In cockroaches, the endoskeleton is made up of a series of interconnected tubes called tracheae, which transport oxygen to the body tissues.
- The tracheae are present throughout the body, including the head, thorax, and abdomen.
3. Exoskeleton:
- The exoskeleton is the external skeleton of an organism.
- In cockroaches, the exoskeleton is made up of a tough, flexible material called chitin.
- The exoskeleton provides protection and support to the insect's body.
- It is present on the head, thorax, and abdomen.
4. Presence of completely developed endoskeleton and exoskeleton:
- While both the endoskeleton and exoskeleton are present in all regions of the cockroach's body, the thoracic region is where they are completely developed.
- The thoracic region is the middle section of the cockroach's body, between the head and the abdomen.
- This region contains the three pairs of legs and the two pairs of wings (in certain species).
- The presence of a completely developed endoskeleton and exoskeleton in the thoracic region allows for efficient movement and flight.
Conclusion:
- The completely developed endoskeleton and exoskeleton are present in the thoracic region of a cockroach.
- This region plays a vital role in the cockroach's movement and flight capabilities.

The body cavity of cockroach is called Haemocoel.

• Explanation:

The body cavity, also known as the coelom, of a cockroach is called Haemocoel.

Haemocoel is a type of body cavity found in many invertebrates, including insects like cockroaches.

It is a large cavity that is filled with a fluid called haemolymph.

The haemolymph circulates throughout the body, bathing the internal organs and tissues.

Unlike the true coelom found in higher animals, the haemocoel does not have a lining of mesodermal cells.

Instead, the haemocoel is formed from the fusion of the blastocoel and the primary body cavity.

It serves as a space for the transport of nutrients, waste products, and hormones.

The haemocoel also plays a role in the immune response, as it contains various types of immune cells.

In cockroaches, the haemocoel is divided into compartments by thin membranes called septa.

Therefore, the correct answer is option D: Haemocoel.

Which cells secrete wax located at the outer surface of the body wall?

The cells that secrete wax located at the outer surface of the body wall are called Oenocytes.

Explanation:

Oenocytes are specialized cells found in insects that secrete wax. They are located in the epidermis, which is the outermost layer of the body wall.

Key Points:

• Oenocytes are cells that secrete wax.


• They are found in the epidermis.


• The wax secreted by oenocytes forms a protective layer on the outer surface of the body wall.

Therefore, the correct answer is Option B: Oenocytes.

The fatbody of cockroach contains:

• Oenocytes: Oenocytes are specialized cells found in the fatbody of cockroaches. They are responsible for the production of cuticular hydrocarbons, which play a role in waterproofing and protection against desiccation.


• Mycetocytes: Mycetocytes are cells found in the fatbody of cockroaches that harbor symbiotic microorganisms. These microorganisms help in the digestion of cellulose and other complex carbohydrates present in the cockroach's diet.


• Trophocytes: Trophocytes are cells found in the fatbody of cockroaches that store and transport nutrients. They play a crucial role in energy storage and distribution throughout the cockroach's body.

Therefore, the correct answer is option D: All of the above. The fatbody of cockroach contains oenocytes, mycetocytes, and trophocytes, each serving different functions in the cockroach's physiology.

Explanation:
The hepatic caeca in cockroaches are derived from the midgut. Here is a detailed explanation:
- Hepatic caeca are blind tubules or outgrowths that are found in the digestive system of cockroaches.
- They are located at the junction of the foregut and midgut.
- The midgut is the region of the digestive system where most of the digestion and absorption of nutrients take place.
- The hepatic caeca play an important role in the digestion and absorption process.
- They secrete digestive enzymes and absorb nutrients from the digested food.
- The hepatic caeca increase the surface area of the midgut, allowing for more efficient digestion and absorption.
- They are involved in the breakdown of complex molecules into simpler forms that can be easily absorbed by the cockroach's body.
- The nutrients absorbed by the hepatic caeca are then transported to the body tissues for energy and growth.
- Therefore, the hepatic caeca in cockroaches are derived from the midgut.
Answer: C. Midgut

Saliva of cockroach contains the enzyme amylase. Here is a detailed explanation:
Enzymes in Saliva of Cockroach:
- Cockroaches have salivary glands that produce saliva, which contains various enzymes.
- One of the enzymes present in the saliva of a cockroach is amylase.
Amylase:
- Amylase is an enzyme that helps in the breakdown of complex carbohydrates into simpler sugars.
- It catalyzes the hydrolysis of starch, glycogen, and other polysaccharides into glucose, maltose, and maltotriose.
- Amylase is classified as an endoamylase, which means it randomly cleaves internal alpha-1,4-glycosidic bonds within the starch molecule.
Functions of Amylase in Cockroach:
- Cockroaches have a diet that primarily consists of complex carbohydrates, such as starch.
- Amylase in their saliva helps in the digestion of these carbohydrates, breaking them down into simpler sugars that can be absorbed and used for energy.
Importance of Understanding Salivary Enzymes:
- Understanding the enzymes present in the saliva of organisms like cockroaches can provide insights into their digestive systems and feeding habits.
- It can also be useful in developing strategies for pest control, as targeting specific enzymes involved in digestion may disrupt their ability to obtain nutrients from their diet.
In conclusion, the saliva of a cockroach contains the enzyme amylase, which plays a crucial role in breaking down complex carbohydrates into simpler sugars for digestion and energy utilization.

Hypopharynx - a tongue-like structure in the floor of the mouth. The salivary glands discharge saliva through it.

The mouthparts of a cockroach are suited for cutting and chewing.
The mouthparts of a cockroach are highly specialized for its feeding habits. They are well-adapted for cutting and chewing solid food. Here is a detailed explanation of how the mouthparts are suited for cutting and chewing:
Labrum: The labrum is the upper lip of the cockroach's mouth. It is a flat, hard structure that helps to protect the mouthparts and guide food into the mouth.
Mandibles: The mandibles are the main cutting and chewing structures of the cockroach. They are strong and toothed, allowing the cockroach to bite and chew through solid food. The mandibles move horizontally, enabling the cockroach to break down food into smaller pieces.
Maxillae: The maxillae are located behind the mandibles and assist in cutting and holding food. They have small, pointed structures called maxillary palps that help the cockroach taste and manipulate its food.
Labium: The labium is the lower lip of the cockroach's mouth. It acts as a protective cover for the other mouthparts and helps in guiding food into the mouth. The labium also has sensory structures called labial palps that aid in taste and food manipulation.
Salivary Glands: The salivary glands of the cockroach produce saliva, which moistens the food and aids in digestion. The saliva contains enzymes that break down the food particles into smaller, more manageable pieces.
Overall, the mouthparts of a cockroach are specialized for cutting and chewing solid food. This adaptation allows the cockroach to efficiently consume a variety of plant and animal matter, making it a successful and adaptable scavenger.

The Cockroach is Omnivorous
- Cockroaches are insects that belong to the order Blattodea. They are known to be highly adaptable and can survive in various environments.
- The diet of a cockroach primarily consists of both plant and animal matter, making them omnivorous.
- They scavenge for food and can consume a wide range of items including fruits, vegetables, grains, meat, decaying matter, and even other insects.
- Cockroaches have powerful jaws that allow them to chew and digest a variety of food sources.
- They are also known to feed on feces, hair, glue, paper, and other organic materials.
- Cockroaches are nocturnal creatures and are most active during the night when they search for food.
- They have the ability to survive for long periods without food and can even resort to cannibalism in extreme situations.
- Cockroaches play an important ecological role by aiding in the decomposition of organic matter.
- Although they are considered pests in human habitats due to their ability to transmit diseases and cause allergies, their omnivorous diet allows them to adapt and thrive in various environments.

Scavenger
Scavengers are organisms that feed on dead or decaying organic matter. In the given scenario, the animal in question feeds on dead insects and its own cast-off cuticle, indicating that it obtains its nutrition from organic material that is no longer alive. Therefore, the correct answer is option B: Scavenger.
Here is a detailed explanation:
- Organic matter: The animal in question feeds on organic matter, which refers to any material derived from living organisms, such as dead plants or animals.
- Dead insects: Dead insects are a source of food for the animal. This suggests that it consumes the remains of insects that have died.
- Own cast-off cuticle: The animal also feeds on its own cast-off cuticle. The cuticle is the outer layer of the animal's exoskeleton, which it sheds periodically as it grows. By consuming its own cuticle, the animal can obtain nutrients from the material it has discarded.
Based on these characteristics, it can be concluded that the animal is a scavenger. Scavengers play an important role in ecosystems by helping to break down and recycle organic matter, contributing to nutrient cycling.

In cockroach, food is crushed in the Gizzard.
The detailed solution is as follows:
1. Introduction:
- Cockroaches are insects that belong to the class Insecta and order Blattodea.
- They have a specialized digestive system to process their food.
2. Anatomy of the cockroach digestive system:
- The digestive system of a cockroach consists of several parts, including the foregut, midgut, and hindgut.
- The foregut is responsible for the initial processing of food.
3. The role of the Gizzard:
- The Gizzard is a part of the foregut in the digestive system of a cockroach.
- It is a muscular organ located between the crop and the midgut.
- The Gizzard is responsible for grinding and crushing the food into smaller particles.
4. Function of the Gizzard:
- When a cockroach ingests food, it first enters the crop, where it is temporarily stored.
- From the crop, the food then moves into the Gizzard.
- The strong muscles in the Gizzard contract and grind the food, breaking it down into smaller pieces.
- This grinding action helps in the mechanical digestion of the food.
5. Passage to the midgut:
- After the food is crushed in the Gizzard, it passes into the midgut.
- The midgut is responsible for the chemical digestion and absorption of nutrients from the food.
6. Conclusion:
- In cockroaches, the Gizzard plays a crucial role in the digestion process.
- It helps in crushing and grinding the food before it moves into the midgut for further digestion and absorption.

Invagination of Cuticle in Cockroach Alimentary Canal
The alimentary canal of a cockroach is a long and tubular structure that is responsible for the digestion and absorption of food. It is divided into three main parts - the foregut, midgut, and hindgut. The invagination of cuticle, also known as the gastric caeca, is found in the anterior and posterior parts of the alimentary canal.
Location of Invagination of Cuticle:
The invagination of cuticle is found in both the anterior and posterior parts of the cockroach alimentary canal.
Functions of Invagination of Cuticle:
The invagination of cuticle in the anterior region of the alimentary canal serves as a storage area for food, while the gastric caeca in the posterior region of the alimentary canal is involved in the digestion and absorption of nutrients.
Significance of Invagination of Cuticle:
1. Storage: The invagination of cuticle in the anterior part of the alimentary canal allows for the storage of food, ensuring a constant supply of nutrients for the cockroach.
2. Digestion and Absorption: The gastric caeca in the posterior part of the alimentary canal increase the surface area for digestion and absorption of nutrients.
3. Adaptation: The presence of gastric caeca in the cockroach's alimentary canal is an adaptation to their omnivorous diet, allowing them to efficiently digest a wide variety of food sources.
In conclusion, the invagination of cuticle in the cockroach's alimentary canal is found in both the anterior and posterior parts. It serves as a storage area for food in the anterior region and aids in digestion and absorption of nutrients in the posterior region.

The inner layer of gizzard of cockroach is covered by cuticle.
The cuticle is the outermost layer of the gizzard and acts as a protective covering. It is composed of a tough, waterproof material called chitin. The cuticle helps to prevent the gizzard from being damaged by the abrasive food particles that pass through it.
Advantages of the cuticle:
- Protection: The cuticle provides a protective barrier for the inner layers of the gizzard, shielding them from mechanical damage caused by the grinding action of the food.
- Waterproofing: The cuticle is impermeable to water, preventing the gizzard from becoming saturated and maintaining its structural integrity.
- Strength: The cuticle is strong and flexible, allowing the gizzard to withstand the repetitive contractions and movements during the grinding process.
- Smooth surface: The cuticle has a smooth surface, which facilitates the smooth passage of food through the gizzard.
In summary, the inner layer of the gizzard of a cockroach is covered by the cuticle, which provides protection, waterproofing, strength, and a smooth surface for the efficient grinding of food particles.

Maximum digestion takes place in the mesenteron of a cockroach.
The mesenteron is the main part of the cockroach's digestive system where the majority of the digestion process occurs. It is also known as the midgut or stomach.
Here are the key points explaining why the mesenteron is the site of maximum digestion in a cockroach:
1. Structure: The mesenteron is a long and coiled tube located in the middle of the cockroach's body. It is lined with a highly folded inner surface, which increases its surface area for efficient digestion and absorption of nutrients.
2. Enzymes: The mesenteron secretes various digestive enzymes, such as proteases, lipases, and carbohydrases. These enzymes break down complex food molecules into simpler forms that can be easily absorbed by the cockroach's body.
3. Absorption: The inner lining of the mesenteron is covered with microvilli, which further increase the surface area for absorption. Nutrients that are broken down by the enzymes are absorbed into the bloodstream through the walls of the mesenteron.
4. Storage: The mesenteron also functions as a storage chamber for food. It can hold a significant amount of ingested food, allowing for continuous digestion and absorption even when the cockroach is not actively feeding.
5. Passage of Undigested Material: After maximum digestion occurs in the mesenteron, the remaining undigested material passes into the hindgut for further processing and elimination from the body.
In conclusion, the mesenteron of a cockroach is the primary site for maximum digestion due to its structural adaptations, secretion of digestive enzymes, efficient absorption capabilities, and storage capacity.

Answer:
The oxygen in cockroaches is carried to the tissues by the trachea. Here's a detailed explanation:
The tracheal system in insects, including cockroaches, is responsible for the exchange of gases. It consists of a network of tubes called tracheae that branch throughout the body to deliver oxygen directly to the tissues.
Advantages of the tracheal system in cockroaches:
1. Efficient oxygen delivery: The tracheal tubes directly supply oxygen to every cell in the cockroach's body, ensuring efficient oxygenation of tissues.
2. No reliance on circulatory system: Unlike in humans and many other animals, cockroaches do not rely solely on a circulatory system to transport oxygen. The tracheal system allows for a more direct and rapid oxygen delivery.
3. Adaptability: The tracheal system can adjust its diameter to regulate the flow of gases, allowing the cockroach to adapt to different environmental conditions.
Other options:
- Skin: While the skin of cockroaches may have some limited gas exchange capabilities, it is not the primary organ responsible for carrying oxygen to the tissues.
- Plasma: Plasma is the liquid component of the blood and does play a role in oxygen transport in some animals, but it is not the primary mechanism in cockroaches.
- Respiratory pigment: Cockroaches do not possess respiratory pigments like hemoglobin, which are responsible for oxygen transport in animals such as humans and many other vertebrates.
Therefore, the correct answer is Option B: Trachea.

Common Features of the Trachea in Rabbit and Cockroach:
There are several similarities between the trachea of a rabbit and a cockroach. These similarities include:
1. Location: Both the trachea of a rabbit and a cockroach are located in the head region of the animals.
2. Structure: The trachea of both animals have a similar structure. They consist of a series of tubes or tubes-like structures that branch out and carry air to different parts of the body.
3. Function: The trachea in both animals is responsible for the transportation of air. It allows the exchange of oxygen and carbon dioxide between the animal's respiratory system and the environment.
4. Strength: The walls of the trachea in both animals are strengthened to prevent collapse. This is important to maintain a clear pathway for air to pass through.
5. Fluid-filled: Both the trachea of a rabbit and a cockroach are not filled with fluid. Instead, they are hollow structures that allow the passage of air.
Therefore, the correct answer is C: The wall in both the trachea of a rabbit and a cockroach is strengthened, which does not allow them to collapse.

Answer:
The Allary muscles in a cockroach are associated or connected with the heart.
The Allary muscles are a set of muscles found in the thoracic region of a cockroach. They are responsible for the movement of the wings during flight. These muscles are connected to the exoskeleton and are used to control the contraction and relaxation of the wing muscles.
The trachea is a system of tubes that transport air to the various parts of the body, including the muscles. While the Allary muscles may be in close proximity to the trachea, they are not directly connected to it.
The legs of a cockroach are used for walking and are controlled by a different set of muscles. The Allary muscles do not have any direct association with the legs.
The alimentary canal is the digestive system of a cockroach, which includes the mouth, esophagus, stomach, and intestines. The Allary muscles do not have any direct connection or association with the alimentary canal.
Therefore, the correct answer is B: heart.

Number of pairs of spiracles in cockroach:
- Spiracles are openings on the body of insects through which they breathe.
- Cockroaches have a total of 10 pairs of spiracles.
- Each pair of spiracles is located on the body segments of the cockroach.
- The spiracles are connected to a network of tubes called tracheae, which deliver oxygen to the cells of the body.
- The spiracles also allow the release of carbon dioxide, which is a waste product of cellular respiration.
Therefore, the correct answer is option D: 10.

Explanation:
To carry oxygen (O₂) to the tissues in cockroaches, the following process occurs:
Tracheal Tubes:
- Oxygen is carried to the tissues by the tracheal tubes.
- Cockroaches have a network of branched tubes called tracheae that deliver oxygen directly to the cells.
- The tracheal tubes transport oxygen from the external environment to the tissues through a system of branching tubes that reach all parts of the body.
In summary, in cockroaches, oxygen is carried to the tissues by the tracheal tubes.
Note: Haemoglobin and haemocyanin are the respiratory pigments found in the blood of other organisms, such as humans and some invertebrates. However, in cockroaches, the main mode of oxygen transport is through the tracheal tubes.

Explanation:
The blood of a cockroach does not contain hemoglobin because it has some other means to carry oxygen directly into the tissues. Here is a detailed explanation:
- Hemoglobin in other organisms: Hemoglobin is a protein found in the red blood cells of most vertebrates and some invertebrates. It is responsible for carrying oxygen from the lungs or gills to the tissues of the body.
- Cockroach respiration: Cockroaches, including the species Periplaneta americana, respire through a system of tubes called tracheae. These tracheae deliver oxygen directly to the tissues, eliminating the need for a specialized oxygen-carrying molecule like hemoglobin.
- Tracheal system: The tracheal system in cockroaches consists of a network of tiny tubes that open to the outside through small respiratory openings called spiracles. Oxygen enters these spiracles and diffuses through the tracheae, reaching every cell in the body. Carbon dioxide, produced as a waste product of metabolism, exits the body through the same system.
- No need for hemoglobin: Since cockroaches have a highly efficient tracheal system that directly delivers oxygen to the tissues, there is no need for hemoglobin or any other oxygen-carrying molecule in their blood. This is why the blood of a cockroach does not contain hemoglobin.
In conclusion, the blood of a cockroach does not contain hemoglobin because it has a specialized tracheal system that directly delivers oxygen to the tissues.

Blood Vessel Arising from First Chamber of Heart in Cockroach:
The blood vessel that arises from the first chamber of the heart in a cockroach is called the anterior aorta. Here is a detailed explanation:
1. Cockroach Heart Structure:
- The heart of a cockroach is a tubular structure divided into several chambers.
- The first chamber is called the pericardial sinus, which is located at the posterior end of the heart.
2. Anterior Aorta:
- The anterior aorta is a blood vessel that arises from the pericardial sinus, the first chamber of the cockroach heart.
- It extends anteriorly (towards the head) from the heart and supplies oxygenated blood to various organs and tissues of the cockroach.
3. Function:
- The anterior aorta acts as the main artery of the cockroach, distributing oxygenated blood to the body.
- It supplies blood to the head, antennae, mouthparts, and other structures located in the anterior region of the cockroach.
4. Circulatory System:
- The circulatory system of a cockroach consists of an open circulatory system.
- In this system, blood flows freely through the body cavity called the hemocoel, bathing the organs directly.
- The blood, called hemolymph, is pumped by the heart and circulated through various vessels, including the anterior aorta.
In conclusion, the blood vessel that arises from the first chamber of the heart in a cockroach is the anterior aorta. It plays a crucial role in supplying oxygenated blood to the anterior regions of the cockroach's body.

The number of chambers in the heart of a cockroach is 13.
Explanation:
- The heart of a cockroach is a tubular structure located along the dorsal side of the body.
- It consists of 13 chambers arranged in a linear fashion.
- These chambers are called ostia and are responsible for pumping hemolymph (the insect equivalent of blood) throughout the body.
- The ostia act as valves, allowing the hemolymph to enter the heart chambers and then contracting to pump it forward.
- The pumping action of the heart helps in the circulation of nutrients, oxygen, and waste products throughout the cockroach's body.
- The number of chambers in the cockroach heart is different from the four-chambered hearts of mammals and the three-chambered hearts of reptiles and amphibians.
- The multi-chambered heart of a cockroach allows for efficient circulation in its body, enabling it to survive and thrive in its environment.

Blood circulation in insects is an open type of circulation. This means that the blood, known as hemolymph, flows freely within the body cavity and comes into direct contact with the organs and tissues. Here is a detailed explanation of blood circulation in insects:
Hemolymph:
- In insects, the blood is called hemolymph. It is a mixture of plasma and hemocytes (similar to white blood cells in vertebrates).
- Hemolymph does not contain red blood corpuscles like in vertebrates.
Open Circulatory System:
- Insects have an open circulatory system, which means that the hemolymph is not enclosed within blood vessels like in vertebrates.
- The hemolymph flows freely through a network of interconnected spaces called sinuses or hemocoels.
- The sinuses are located between the organs and tissues, allowing direct exchange of nutrients, gases, and waste products.
Heart and Arteries:
- Insects have a tubular heart called the dorsal vessel.
- The dorsal vessel runs along the back of the insect's body and pumps the hemolymph forward.
- The hemolymph is propelled through the dorsal vessel by rhythmic contractions of the heart.
- Arteries, also known as aorta, branch out from the dorsal vessel and distribute the hemolymph to various parts of the body.
Openings and Valves:
- The hemolymph enters the sinuses through openings called ostia.
- Valves prevent the backward flow of hemolymph and ensure that it flows in one direction.
Exchange of Gases and Nutrients:
- As the hemolymph flows through the sinuses, it comes into direct contact with the organs and tissues.
- This allows for the exchange of gases, nutrients, and waste products between the hemolymph and the cells.
- Oxygen is absorbed by the hemolymph from the tracheal system, and carbon dioxide is released back into the tracheal system for excretion.
Immune Function:
- Hemocytes present in the hemolymph play a crucial role in the insect's immune response.
- They are responsible for defending against pathogens and foreign invaders, similar to the role of white blood cells in vertebrates.
In conclusion, blood circulation in insects is an open type of circulation where the hemolymph flows freely through sinuses and comes into direct contact with the organs and tissues. This allows for efficient exchange of gases, nutrients, and waste products, as well as the immune response.

Heart of cockroach
The heart of a cockroach is a specialized organ responsible for pumping hemolymph (cockroach's version of blood) throughout its body. Here are the key details about the heart of a cockroach:
Structure:
- The heart of a cockroach is longitudinal and beaded. This means that it is made up of a series of interconnected chambers that run along the length of the cockroach's body.
Number of chambers:
- The heart of a cockroach has four chambers. These chambers are called ostia and are responsible for receiving and pumping hemolymph.
Position:
- The heart is located ventral to the gut. This means that it is situated underneath the cockroach's digestive system.
Function:
- The heart of a cockroach pumps hemolymph, which transports nutrients and oxygen to the cockroach's tissues and organs. It also helps in the removal of waste products from the body.
In summary, the heart of a cockroach is a longitudinal and beaded structure with four chambers. It is located ventral to the gut and is responsible for pumping hemolymph throughout the cockroach's body.

The color of hemolymph in a cockroach is colorless. Below is a detailed explanation:
Hemolymph in Cockroach:
- Hemolymph is the circulatory fluid in insects, including cockroaches.
- It is analogous to blood in vertebrates but does not contain red blood cells or hemoglobin.
- Hemolymph is a clear, colorless fluid that fills the body cavity (hemocoel) of a cockroach.
Function of Hemolymph:
- Hemolymph plays a vital role in the transport of nutrients, waste products, hormones, and immune cells throughout the cockroach's body.
- It also helps in maintaining the osmotic balance, temperature regulation, and protection against pathogens.
Why is Hemolymph Colorless?
- Unlike vertebrates, insects do not have specialized oxygen-carrying cells like red blood cells.
- The absence of pigments, such as hemoglobin, in the hemolymph results in its colorless appearance.
- Instead, gases such as oxygen and carbon dioxide are directly dissolved in the hemolymph.
Conclusion:
The color of the hemolymph in a cockroach is colorless. It serves important functions in the transport of nutrients and waste products, as well as maintaining homeostasis and providing protection against pathogens.

Physiology of the Heart in Cockroach
The heart of a cockroach is a unique organ that exhibits certain physiological characteristics. Here, we will discuss the physiology of the cockroach heart and why it is classified as neurogenic.
Neurogenic Heart
- The term "neurogenic" refers to the fact that the heart's contractions are initiated by nerve impulses.
- In the cockroach, the heart consists of a tubular structure with several chambers, called ostia, which allow the entry and exit of blood.
- The contractions of the heart are controlled by a group of nerve cells called the cardiac ganglion, which is located near the heart.
- Nerve impulses from the cardiac ganglion stimulate the heart muscles to contract, leading to the circulation of hemolymph (the insect equivalent of blood) throughout the body.
Comparison with Myogenic Heart
- In contrast to the cockroach heart, a myogenic heart is one that initiates contractions on its own, without external nerve impulses.
- In mammals, including humans, the heart is myogenic, meaning it has its own pacemaker cells (sinoatrial node) that generate electrical impulses to regulate its contractions.
- The myogenic nature of the mammalian heart allows for more precise control over heart rate and rhythm.
Importance of Neurogenic Heart in Cockroach
- The neurogenic nature of the cockroach heart is suited to its simple circulatory system and basic physiological requirements.
- The nerve impulses from the cardiac ganglion ensure that the heart contracts rhythmically and efficiently, allowing for the distribution of hemolymph to various body tissues.
- While the neurogenic heart may not offer the same level of control as a myogenic heart, it is sufficient for the cockroach's needs.
In conclusion, the heart of a cockroach is classified as neurogenic because its contractions are initiated by nerve impulses from the cardiac ganglion. This neurogenic nature allows for the rhythmic and efficient circulation of hemolymph throughout the cockroach's body.

Main excretory product of cockroach is:
The main excretory product of cockroach is uric acid.
Explanation:
Cockroaches are insects that belong to the class Insecta and the order Blattodea. They have a specialized excretory system that allows them to eliminate waste products from their bodies. The excretory system in cockroaches consists of Malpighian tubules, which are long, slender tubes located in the abdominal region.
Here are the reasons why uric acid is the main excretory product of cockroaches:
- Uric acid is a nitrogenous waste product that is formed from the breakdown of proteins and nucleic acids in the body.
- Unlike mammals, cockroaches do not have a well-developed kidney system to filter and eliminate waste products like urea or ammonia. Instead, they rely on the Malpighian tubules to remove waste from their bodies.
- The Malpighian tubules actively transport uric acid from the surrounding hemolymph (cockroach blood) into the tubules.
- Uric acid is insoluble in water and forms a paste-like substance, making it suitable for excretion in a terrestrial environment.
- By excreting uric acid, cockroaches can conserve water since uric acid requires less water for its excretion compared to other nitrogenous waste products like urea or ammonia.
In conclusion, the main excretory product of cockroaches is uric acid, which is excreted through their Malpighian tubules. This adaptation allows them to efficiently conserve water in their terrestrial habitat.

Function of Malpighian tubules of cockroach:
The Malpighian tubules are long, slender, and thread-like structures present in the digestive system of insects, including cockroaches. These tubules play a vital role in the excretory system of cockroaches. The main functions of the Malpighian tubules are as follows:
1. Excretion: The primary function of the Malpighian tubules is excretion. They help in the removal of waste materials, including nitrogenous compounds like uric acid, from the hemolymph (insect blood). The tubules actively transport these waste products from the hemolymph into the tubules for elimination.
2. Osmoregulation: The Malpighian tubules also play a crucial role in maintaining the osmotic balance in the body of cockroaches. They help in regulating the concentration of ions, salts, and water in the hemolymph. By selectively reabsorbing water and ions, the tubules prevent excessive loss of water and maintain the appropriate fluid balance in the body.
3. Detoxification: In addition to excretion and osmoregulation, the Malpighian tubules also aid in the removal of toxic substances from the body of cockroaches. They help in detoxifying harmful compounds, such as metabolic wastes and toxins, by actively transporting them into the tubules for elimination.
4. Acid-base balance: The Malpighian tubules are involved in maintaining the acid-base balance in the hemolymph of cockroaches. They regulate the pH level by selectively excreting or reabsorbing ions, such as hydrogen and bicarbonate ions, to maintain the appropriate acid-base equilibrium.
Overall, the Malpighian tubules of cockroaches play a crucial role in excretion, osmoregulation, detoxification, and acid-base balance, ensuring the proper functioning of the insect's excretory system.

Excretory Organs of Cockroach
The excretory organs of a cockroach are responsible for the elimination of waste products from its body. These organs help in maintaining the osmotic balance and getting rid of metabolic wastes. The excretory organs of a cockroach are as follows:
1. Malpighian tubules:
- These are the primary excretory organs in a cockroach.
- They are long, slender tubules located in the hind gut.
- The number of malpighian tubules varies from 100 to 150 in a cockroach.
- These tubules are responsible for the removal of nitrogenous waste products, such as uric acid.
- They actively transport waste products from the hemolymph into the hind gut for excretion.
2. Nephridia:
- Nephridia are also present in the cockroach, but they are not the main excretory organs.
- They are tubular structures that act as excretory organs in many invertebrates.
- In the cockroach, nephridia are found in the abdomen segments.
- They help in removing metabolic waste products and maintaining the osmotic balance in the body.
3. Trachea:
- Trachea are the respiratory tubes in insects, including cockroaches.
- While they are primarily involved in respiration, they also play a role in excretion.
- Trachea help in the removal of metabolic waste gases, such as carbon dioxide, from the body.
4. Kidney:
- Unlike in vertebrates, cockroaches do not have true kidneys.
- The excretory functions of the kidney are performed by the malpighian tubules and nephridia in cockroaches.
In conclusion, the excretory organs of a cockroach include malpighian tubules, nephridia, trachea, and they do not have true kidneys. These organs work together to eliminate waste products and maintain osmotic balance in the cockroach's body.

The nerve cord of a cockroach is:
Answer: A: Double, ventral and solid
Explanation:
The nerve cord in a cockroach is a long, tubular structure that runs along the ventral (underside) part of its body. It is composed of a pair of nerve cords that are fused together. Here is a detailed explanation of the nerve cord of a cockroach:
1. Structure:
- The nerve cord is double, meaning it consists of two parallel nerve cords that are closely associated with each other.
- It is located ventrally, which means it is situated on the underside of the body.
- The nerve cord is solid, meaning it does not have a hollow cavity.
2. Function:
- The nerve cord serves as the main pathway for transmitting nerve impulses throughout the cockroach's body.
- It connects the brain to the various segments of the body, allowing for coordinated movement and sensory perception.
3. Segments:
- The nerve cord is segmented, with ganglia (clusters of nerve cell bodies) present in each segment.
- Ganglia act as processing centers for incoming and outgoing nerve signals.
4. Connectivity:
- The nerve cord is connected to the brain at the anterior end and extends posteriorly along the entire length of the body.
- It branches out into smaller nerves, which innervate different parts of the body.
Overall, the double, ventral, and solid nerve cord of the cockroach allows for efficient communication and coordination of nerve signals, enabling the insect to perform various activities and respond to its environment.