Structural Organisation In Animals - Class 11 Medical Biology - Extra Questions

Neuron, also known as nerve cell, is the largest cell in the body and found in nervous system. They help in transmitting the impulse from the effector to the receptor.

Haemocoel:-

Cockroach belongs to phylum Arthropoda. The body is divided into head thorax and abdomen. The abdomen consists of 10 segments. The boat shaped 7$$^{th}$$ segment together with the 8$$^{th}$$ and 9$$^{th}$$sterna forms a brood or genital part. In both sexes, the 10th segment bears of pair of jointed filamentous structures called anal cerci.

• Malpighian tubules are present as a ring of the filamentous structure at the junction of midgut and hindgut.
• The Malpighian tubule system is an excretory and osmoregulatory system found in some insects like cockroaches.

The diagram represents the parts of neuron. 

A neuron is the structural and functional unit of the nervous system. It is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. The neuron consists of three main parts the cell body or soma, dendrites, and axons.

(i) Antennae. It is not the masticating part. The rest three are mouth parts of cockroach. 

Eight

Chewing type.

Three parts, viz., head, thorax and abdomen.

The alimentary canal of cockroach is divided into 3 parts that is foregut midgut and hand cut forget is differentiated into 5 parts buckle chamber pharynx oesophagus crop and gizzard disorders muscular and internally provided with 6 circular teeth that help in crushing the food that is also known as mesenteron and this is short tubular and lined with granular endoderm at interior of Magenta on there are 89 plan to lymphatic CK present their function is secretion of digestive enzymes on the interior this midgard is not 95 cuticle but it is covered by a thin and transparent membrane which is made up of chitin and proteins hindgut comprises of ileum colon and rectum the wall of rectum is provided with six rectify which helps in absorption of water and salt at the junction of the Forgotten midgut get 7 or 8 finger like structure present that are known as hepatic caeca

The gizzard is an organ found in the digestive tract of some animals, including archosaurs (pterosaurs, crocodiles, alligators, and dinosaurs, including birds), earthworms, some gastropods, some fish, and some crustaceans. This specialized stomach constructed of thick muscular walls is used for grinding up food, often aided by particles of stone or grit. In certain insects and molluscs, the gizzard features chitinous plates or teeth.

Haemocoel

Nymph.

Helps in the formation of ootheca.

Myelinated nerve fibres	Unmyelinated nerve fibres
Nerve fibres are covered by a myelin sheath.	Nerve fibres are not covered by a myelin sheath.
It consists of nodes of Ranvier and the speed of transmission of impulses is high.	Does not contain nodes of Ranvier and the speed of impulse transmission is low.
There is no loss of impulse during transmission.	There is a loss of impulse during transmission.

Structure of neuron: Nerve cells or neurons are the structural and functional units of the nervous system. It consists of three major parts namely, Cell body, dendrites, Axon.
Cell Body: It is irregular in shape or polyhedral. It contains cytoplasm and certain granular bodies called Nissles granules which contain a group of ribosomes for protein synthesis.
Dendrites: Dendrites are short fibres which branch repeatedly and protrude out of the cell body. They transmit electrical impulse towards the cyton.
Axon: They are long fibres arising from the cell body with a branched distal end. It terminates in a synaptic knob. It is filled with neurotransmitters.
Parts of Axon:
a. Axoplasm: It is the cytoplasm of an axon.
b. Myelin sheath: It is made up of many layers of Schwann cells.
c. Neurilemma: The outermost layer of Schwann cells.
d. Nodes of Ranvier: These are gaps left by a myelin sheath.

Prostomium	Peristomium
Prostomium is a dorsal lobe which is present on the ventral mouth.	Peristomium is the first segment of earthworm with a ventral mouth.
It overhangs the mouth of an earthworm.	It surrounds the mouth opening.

Septal nephridium	Pharyngeal nephridium
Present on both sides of inter-segmental septa.	They are present as three paired tufts in the fourth, fifth and sixth segments.
They open into the intestine.	They are closed.

• An axon or nerve fibre, is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action potentials away from the nerve cell body.
•  The myelinated nerve fibres contain a myelin sheath, surrounding the axons of the nerve cells. 
• Schwann cells or oligodendrocytes in myelinated nerve fibres produce a myelin sheath. 
• The saltatory conduction in the myelinated nerve fibres increases the speed of conduction of the nerve impulses.

In the pre-oral cavity at the base of the hypopharynx.

They consist of labrum, mandibles, maxillae, labium and hypopharynx.

The digestive system consists of an alimentary canal and digestive glands. The alimentary canal of cockroach is divided into foregut, midgut, and hindgut. the foregut opens into a gap, where undigested food is temporarily stored. the mouth opens into a short tubular pharynx, leading to a narrow tubular passage, the esophagus. The gastric sacks contain bacteria that the cockroach uses to digest its food.