Anatomy of Cockroach Questions in English

(C) The mouthparts of a housefly $(Musca \text{ } domestica)$ are of the sponging type.
These mouthparts consist of the labrum, epipharynx, labium, and maxillary palps.
Mandibles are completely absent in the housefly, as they feed on liquid food and do not require biting or chewing structures.

(A) The excretory organs of the cockroach are $Malpighian$ tubules.
These are yellow-colored,thin,filamentous structures.
They are present at the junction of the midgut and the hindgut.
They help in the removal of excretory products from the hemolymph.

(A) In $Cockroach$, the blood (hemolymph) lacks respiratory pigments like hemoglobin.
Therefore, the blood does not play any role in the transport of oxygen.
Instead, oxygen is transported directly to the tissues through a system of air tubes called the tracheal system.
In contrast, $Earthworms$ use hemoglobin dissolved in plasma, $Frogs$ use hemoglobin in red blood cells, and $Beetles$ (though insects) are often compared in broader contexts, but the $Cockroach$ is the classic example of an insect where the tracheal system is the sole respiratory mechanism.

(B) The conglobate gland,also known as the phallic gland,is a characteristic accessory reproductive gland found in the male cockroach. It is an elongated,flat structure located on the right side of the ventral nerve cord. It opens to the exterior through a small pore located close to the male gonopore.

(A) Ecdysone is a steroid hormone that regulates the process of moulting (ecdysis) in insects.
It is synthesized and secreted by the prothoracic glands,which are endocrine glands located in the thorax of the insect.

(D) The correct answer is $D$. If the food material of a housefly is solid,such as a sugar crystal,the fly first pours a little saliva or regurgitates droplets of liquid from its crop to liquefy it. After the sugar is dissolved,the fly sucks the resulting liquid,which enters the tubular pseudo-tracheae through capillary action.

(B) The nervous system of a cockroach consists of a series of fused segmental ganglia joined by paired longitudinal connectives on the ventral side.
There are $3$ pairs of thoracic ganglia and $6$ pairs of abdominal ganglia.
Thus,the correct option is $B$.

(B) The correct answer is $B$.
In cockroaches,the tracheal tubes are lined with spiral thickenings of cuticle known as intima,which prevents the tracheal tubes from collapsing.
Similarly,the trachea of mammals is supported by $C$-shaped cartilaginous rings,which also ensure that the tracheal walls remain non-collapsible,allowing for continuous airflow during respiration.

(B) The development of the cockroach,$Periplaneta$ $americana$,is paurometabolous,which means that development occurs through the nymphal stage.
The nymph grows by moulting about $13$ times to reach the adult form.
The next to last nymphal stage has wing pads but only adult cockroaches have wings.
This entire process of metamorphosis from the nymphal stage to the adult form takes approximately $40-70$ days.

(D) In cockroaches,the blood (hemolymph) does not contain any respiratory pigment like hemoglobin to transport oxygen.
Instead,they possess a specialized network of air tubes called the tracheal system.
Oxygen enters the body through small openings called spiracles and travels directly to the tissues through a network of fine tubes known as tracheoles.
Therefore,oxygen reaches the tissues directly through tracheoles without the need for a blood-based transport system.

(A) The heart of a cockroach is $13$-chambered. Each chamber,except for the last one,possesses a pair of small lateral apertures known as ostia,which open into the pericardial sinus. This is a unique anatomical feature of the cockroach.

(B) In $Cockroach$,the tracheal system opens to the exterior through $10$ pairs of spiracles.
The first pair of spiracles is located on the mesothorax,and the third pair is located on the first abdominal segment.
These specific pairs (first and third) are larger in size and remain open at all times to facilitate continuous gas exchange.

(B) In insects,the $Juvenile$ $Hormone$ $(JH)$ is secreted by the $Corpora$ $allata$. This hormone is responsible for maintaining juvenile characteristics and preventing metamorphosis into the adult stage during the larval or nymphal stages. When the $Corpora$ $allata$ are removed,the level of $JH$ drops significantly. In the absence of $JH$,the insect undergoes premature metamorphosis and develops into an adult.

(C) In a $Cockroach$, the circulatory system is of the open type, meaning the blood $(haemolymph)$ flows through body cavities $(haemocoel)$ and bathes the tissues directly.
Unlike vertebrates, where the circulatory system is responsible for transporting respiratory gases ($O_2$ and $CO_2$), the $Cockroach$ has a separate, highly efficient tracheal system for respiration.
The tracheal system consists of a network of tubes that deliver oxygen directly to the tissues and remove carbon dioxide.
Because the circulatory system is not involved in gas exchange, the lack of closed vessels does not hinder its physiological function.

(C) In female cockroaches,the ootheca is formed by the secretion of the colleterial glands. These glands secrete a proteinaceous substance that hardens to form the egg case (ootheca) around the eggs deposited in the genital pouch.

(C) The Malpighian tubules in a cockroach are thin,filamentous structures that play a crucial role in excretion and osmoregulation.
They are located at the junction of the midgut and hindgut.
The number of these tubules typically ranges from $100$ to $150$.
They are arranged in $6-8$ bundles,which help in the efficient removal of nitrogenous wastes from the hemolymph.

(A) Alary muscles are a pair of triangular,fan-like muscles found in the floor of the pericardial sinus of a cockroach.
These muscles are attached to the heart and help in the circulation of hemolymph.
The contraction of alary muscles and the respiratory movements of the abdomen increase the pumping force of the cockroach's heart,thereby facilitating the circulation of blood.

(C) The correct answer is $C$.
In cockroaches,the mandibles are a pair of heavily sclerotized,triangular structures with jagged teeth-like edges.
These structures are operated by powerful abductor and adductor muscles,which move them in a horizontal plane.
This movement allows the cockroach to effectively cut and chew food particles that are positioned between the mandibles by the first maxillae.

(A) In cockroaches,the salivary glands are paired structures. The ducts from these glands unite to form a common salivary duct. This common salivary duct opens at the base of the hypopharynx,which is a tongue-like structure situated in front of the labium.

(B) The alimentary canal of a cockroach is divided into three regions: foregut,midgut,and hindgut.
The foregut includes the mouth,pharynx,esophagus,crop,and gizzard (also known as the proventriculus).
The gizzard is a thick,muscular organ that helps in grinding food particles.
Therefore,it is a part of the digestive system.

(B) The heart of a cockroach is an elongated,tubular structure located along the mid-dorsal line of the thorax and abdomen.
It consists of $13$ funnel-shaped chambers with ostia on either side.
Blood from the sinuses enters the heart through these ostia and is pumped anteriorly to the sinuses by the contraction of the heart chambers.

(C) Cockroaches are omnivorous insects that feed on a variety of plant and animal materials.
While they consume cellulose-rich plant matter,they do not possess the genetic capability to synthesize the enzyme cellulase themselves.
Instead,they rely on symbiotic microorganisms (bacteria and protozoa) present in their gut to produce cellulase,which helps in the breakdown of cellulose.
Therefore,the correct answer is that the enzyme is synthesized by the symbiotic bacteria residing in the midgut.

(D) In cockroaches,the blood is known as haemolymph.
It consists of colourless plasma and haemocytes.
Unlike vertebrates or some other invertebrates,the haemolymph of a cockroach does not contain any respiratory pigment like haemoglobin or haemocyanin.
Therefore,the blood of a cockroach does not play a role in the transport of respiratory gases (oxygen or carbon dioxide).
Instead,respiration occurs through a network of tracheae that deliver oxygen directly to the tissues.

(C) The trachea of a cockroach is supported by chitinous rings called intima,which prevent the tracheal tubes from collapsing. Similarly,the trachea of a rabbit is supported by incomplete cartilaginous rings that prevent the tracheal walls from collapsing or deforming. Therefore,the similarity is that the walls of both cannot be deformed.

(A) In $Cockroach$, the blood (hemolymph) does not contain any respiratory pigments like hemoglobin.
Oxygen is transported directly to the tissues through a system of air-filled tubes called the tracheal system.
Therefore, the blood does not play a role in the transport of oxygen.

(D) The correct statement is $(d)$. The circulatory system of a cockroach is of the open type. The heart of a cockroach is pulsatile and consists of $13$ inverted funnel-shaped segmental chambers. Each chamber (except the last one) has a pair of lateral apertures called ostia,which allow blood to enter the heart from the pericardial sinus.

(A) The blood of the cockroach $(Periplaneta)$ lacks respiratory pigments like hemoglobin.
Therefore,it does not transport oxygen.
Instead,the respiratory system consists of a network of tracheae (respiratory tubules) that open to the exterior through spiracles,which directly deliver $O_2$ to the tissues.

(D) The excretory organs of a cockroach are the Malpighian tubules.
These tubules are yellow-colored,thin,filamentous structures.
They are present at the junction of the midgut and the hindgut.
They help in the removal of excretory products from the hemolymph.

(A) Malpighian tubules are the main excretory organs in insects like cockroaches.
They are blind-ended tubules attached to the junction of the midgut and hindgut.
These tubules absorb nitrogenous waste products and water from the haemolymph (the body fluid of insects).
These wastes are then converted into uric acid and passed into the alimentary canal to be excreted out through the anus.

(B) The compound eye of insects, such as the house fly, is composed of several independent visual units called "ommatidia".
Each ommatidium acts as a separate photoreceptor unit, allowing the insect to form a mosaic image.
$Pheretima$ (earthworm) has light-sensitive cells but lacks compound eyes.
$Pila$ (snail) and $Sepia$ (cuttlefish) possess camera-type eyes, which are structurally different from the compound eyes of insects.

(B) Pheromones are chemical substances secreted by organisms,specifically by $Exocrine$ glands,which are released into the external environment to influence the behavior or physiology of other individuals of the same species.
In insects,these glands are typically located on the body surface or associated with specific structures to facilitate the release of these signaling molecules into the air or onto surfaces.

(B) The phallic organs (also known as phallomeres) in a male cockroach are chitinous asymmetrical structures that surround the male gonopore.
They are part of the male reproductive system and function as copulatory organs during mating.

(D) In the development of the alimentary canal,the $Stomodaeum$ (foregut) and $Proctodaeum$ (hindgut) are formed by the invagination of the ectoderm.
In contrast,the $Mesodaeum$ (midgut) is derived from the endoderm.
Therefore,both $Stomodaeum$ and $Proctodaeum$ originate from the ectoderm.

(D) The silk glands in silkworms are modified salivary glands. The anterior parts of both silk glands unite to form a common duct. This duct opens through a small pore located on a structure called the spinneret,which is situated on the anterior part of the hypopharynx. The secretion from this gland hardens upon contact with air to form silk threads.

(B) Cockroaches are uricotelic organisms,meaning they excrete nitrogenous waste primarily in the form of uric acid.
This adaptation helps them conserve water,which is essential for their survival in terrestrial environments.
The Malpighian tubules are the primary excretory organs in cockroaches that remove uric acid from the hemolymph.

(A) Alary muscles are specialized fan-shaped muscles found in cockroaches $(Periplaneta \text{ } americana)$.
They are typically $12$ pairs in number.
These muscles are attached to the terga of the abdominal segments and the dorsal diaphragm.
Their primary function is to help in the circulation of haemolymph within the haemocoel of the cockroach by contracting and relaxing, which aids in the pumping action of the heart.

(A) In the cockroach,the circulatory system consists of a tubular heart and a series of vessels. The lateral oesophageal hearts (also known as lateral vessels) are specialized structures that connect the dorsal vessel (dorsal blood vessel) to the ventral vessel (ventral blood vessel). This connection facilitates the circulation of haemolymph throughout the body cavity.

(B) In insects,$Oenocytes$ are specialized cells found in the body cavity or associated with the epidermis. These cells are responsible for the synthesis and secretion of hydrocarbons and wax,which form a protective layer on the outer surface of the body wall (cuticle) to prevent desiccation.

(C) In cockroaches,the respiratory system consists of a network of tubes called the tracheal system.
Air enters the body through small openings called spiracles.
The tracheal tubes branch into finer tubes called tracheoles,which carry oxygen directly to the tissues.
Therefore,the blood of a cockroach does not contain respiratory pigments like hemoglobin to transport oxygen,and the tracheal system is responsible for gaseous exchange.

(B) The digestive system of a cockroach includes salivary glands that secrete saliva.
This saliva contains enzymes,primarily amylase,which helps in the digestion of carbohydrates (starch) present in their food.
Lipase,pepsin,and trypsin are not the primary enzymes found in cockroach saliva; pepsin and trypsin are typically associated with protein digestion in the midgut or other organisms.

(C) The conglobate gland (also known as the phallic gland) is a characteristic accessory reproductive gland found in the male reproductive system of the cockroach $(Periplaneta \text{ } americana)$.
It is located near the ejaculatory duct and its secretion is believed to help in the formation of the spermatophore.

(C) In cockroaches,the Malpighian tubules are the primary excretory organs. They are thin,filamentous structures attached to the junction of the midgut and hindgut. They absorb nitrogenous waste products from the hemolymph and convert them into uric acid,which is then excreted through the hindgut. Thus,their main function is excretion.

(B) In a cockroach,the heart consists of an elongated muscular tube lying along the mid-dorsal line of the thorax and abdomen.
It is differentiated into funnel-shaped chambers with ostia on either side.
Blood from the sinuses enters the heart through these ostia and is pumped anteriorly to the sinuses by the contraction of the heart.
The alary muscles are paired triangular muscles attached to the lateral sides of the heart chambers.
These muscles help in the circulation of blood by expanding the heart chambers.

(D) In cockroaches,the body cavity is not a true coelom. Instead,it is filled with blood and is known as the haemocoel. The internal organs of the cockroach lie in this blood-filled cavity,which is part of the open circulatory system.

(C) The circulatory system of a cockroach is of the open type.
The heart of a cockroach consists of an elongated muscular tube lying along the mid-dorsal line of the thorax and abdomen.
This tube is differentiated into $13$ funnel-shaped chambers with ostia on either side.
Therefore,the correct answer is $13$.

(C) In cockroaches,the characteristic pungent odor is produced by the secretions of the abdominal glands (also known as stink glands). These glands are located in the $6^{th}$ and $7^{th}$ abdominal segments in both sexes. The secretion serves as a defense mechanism against predators.

(C) The heart of a cockroach $(Periplaneta \ americana)$ is an elongated,tubular structure located along the mid-dorsal line of the thorax and abdomen. It consists of $13$ funnel-shaped chambers with ostia on either side. Therefore,the correct description is that it is elongated and tubular.

(D) In cockroaches,the blood (hemolymph) is colorless because it lacks respiratory pigments like hemoglobin.
Instead of using blood to transport oxygen,cockroaches utilize a specialized network of air tubes called the tracheal system.
Air enters the body through small openings called spiracles and travels directly to the tissues via tracheae and tracheoles.
Therefore,oxygen is transported to the tissues directly through this tracheal system,making hemoglobin unnecessary for gas exchange.

(B) In the digestive system of a cockroach,the alimentary canal is divided into three regions: foregut,midgut,and hindgut. The foregut includes the mouth,pharynx,oesophagus,crop,and gizzard. The crop is used for storing food,while the gizzard (also known as proventriculus) has thick,muscular walls and chitinous teeth that help in the grinding of food particles.

(B) In female cockroaches,the colleterial glands are accessory reproductive glands. Their primary function is to secrete a proteinaceous substance that hardens to form the protective capsule known as the $Ootheca$ (egg case) around the eggs. Therefore,they play a crucial role in $Ootheca$ formation.