Test: Cockroach - NEET MCQ

Insects including cockroach excrete nitrogenous waste in the form of soluble potassium urate which is liberated into the haemolymph and taken up by the cells lining the Malpighian tubules. The tubules facilitate the absorption of urate by stirring up the blood. In the cells of the tubule the potassium urate reacts with water and carbon dioxide(from respiration) to form potassium hydrogen carbonate and uric acid. The former is absorbed back into the blood, but the later is excreted.

Mast cells are the large cells with densely granular cytoplasm that is found in connective tissues. Their granules contain histamine which is a vasodilator, heparin which is an anticoagulant and serotonin which acts as a mediator o f inflammation and allergic reactions. Vasopressin is a hormone secreted by posterior pituitary gland. Calcitonin is a hormone secreted by thyroid gland. Melanin is a pigment produced by specialized epidermal cells called melanocytes. Relaxin is a hormone produced by the corpus luteum and placenta during the terminal stages of pregnancy.

The abdomen in a male and female cockroach is made up of 10 segments. The 7th, 8th and 9th sterna form a genital pouch in females. In males, the genital pouch is present at the hind end of the abdomen. The male cockroach has thread-like anal styles, which are missing in the female cockroach.

The heart of the cockroach is elongated, thick, muscular, tubular and 13-chambered. It lies in the pericardial sinus of the hemocoel. Each chamber of the heart receives oxygenated blood from the dorsal sinus through one pair of slit-like openings called ostia. The heart contracts in a posteroanterior direction and the blood also flows posteroanterior. The alary muscles are responsible for the circulation of blood.

Cockroach antennae have been extensively used for studying the multifunctional sensory appendage that generates the olfactory, gustatory, tactile, thermal, and humidity senses. Of the variety of senses, the tactile sense is thought to play a key role for perceiving physical objects.

Periplaneta has open circulatory system i.e. the blood does not flow in blood vessels but flows in a haemocoel (body cavity). The circulatory systems of all vertebrates, as well as of annelids (for example, earthworms) and cephalopods (squid and octopus) are closed, in which the blood never leaves the system of blood vessels consisting of arteries, capillaries and veins.

Statement: The anal styles are absent in females.
Explanation:
The statement is true for cockroaches. Here is a detailed explanation:
1. Anal styles: Anal styles are specialized structures found in the male cockroach. They are located on the posterior end of the abdomen and are used during mating to hold onto the female.
2. Absence in females: Unlike males, female cockroaches do not possess anal styles. This is a distinguishing characteristic between male and female cockroaches.
3. Function: The absence of anal styles in females does not affect their reproductive capabilities. Female cockroaches still have the ability to reproduce and lay eggs.
4. Other reproductive structures: Female cockroaches have other reproductive structures such as ovaries, oviducts, and genital openings, which are responsible for egg production and mating.
In conclusion, the statement "The anal styles are absent in females" is true for cockroaches.

- Anal cerci are a pair of appendages at the end of the abdomen, arising from near the 10th segment of the body of a cockroach. These are present in both males and females. Anal cerci are important sense organs of the organism as they are wind sensitive and detect vibrations.

- The abdomen is broader in female than in the male. In male in addition to cerci, the 9th sternum bears a short unjointed anal stylus, which is absent in females.

Cockroach has separate male and female bodies, hence it is unisexual. Rest all the animals listed are hermaphrodites in which male and female gametes are produced in the same animal body.
So, the correct answer is option A.

 In rat right kidney is sligtly higher than left because all the organs are concentrated towards left, only in human beings left kidney is higher. In earthworm the correct sequence of alimentary canal is pharynx, oesophagus, gizzard, stomach and intestine. In Frog, neck is absent.