Anatomy — Revision Notes

⚡ 30-Second Revision

Digestive System: — Foregut (Crop: storage, Gizzard: grinding), Midgut (Hepatic caeca: enzymes, absorption), Hindgut (Rectum: water reabsorption).
Circulatory System: — Open type, Haemocoel, Haemolymph (no $ext{O}_2$ transport), Dorsal tubular heart (13 chambers), Ostia, Alary muscles.
Respiratory System: — Tracheal system, 10 pairs Spiracles (2 thoracic, 8 abdominal), Tracheae, Tracheoles (direct $ext{O}_2$ delivery).
Excretory System: — Malpighian tubules (100-150), Uric acid excretion (midgut-hindgut junction).
Nervous System: — Supra-oesophageal ganglion (brain), Sub-oesophageal ganglion, Ventral nerve cord (3 thoracic, 6 abdominal ganglia).
Male Repro: — Testes, Vasa deferentia, Ejaculatory duct, Mushroom gland, Phallic gland, Spermatophore, Phallomeres.
Female Repro: — Ovaries (8 ovarioles each), Oviducts, Vagina, Spermatheca (sperm storage), Collateral glands (Ootheca formation), Genital pouch (14-16 eggs/ootheca).

2-Minute Revision

For a quick revision of cockroach anatomy, focus on the core components and their functions. The digestive system is a complete tube: food is stored in the crop, ground in the gizzard, digested and absorbed in the midgut with help from hepatic caeca, and water is reabsorbed in the hindgut.

The circulatory system is open, meaning haemolymph (which doesn't carry oxygen) fills the body cavity, circulated by a dorsal heart. Respiration is direct via the tracheal system, with air entering through 10 pairs of spiracles and reaching cells via tracheoles.

Excretion is handled by Malpighian tubules, producing uric acid. The nervous system is decentralized, with a brain and ventral nerve cord with segmental ganglia. In reproduction, males have testes and accessory glands (mushroom, phallic) forming a spermatophore, while females have ovaries (8 ovarioles each), spermatheca for sperm storage, and collateral glands that form the protective ootheca, typically containing 14-16 eggs.

Remember the key numbers and unique features like the absence of respiratory pigment in haemolymph and direct oxygen delivery.

5-Minute Revision

Let's consolidate the key aspects of cockroach anatomy for NEET. The digestive system begins with the mouth, leading to the pharynx, oesophagus, and the large crop for food storage. Following this is the muscular gizzard (proventriculus), armed with chitinous teeth for mechanical grinding.

At the midgut's anterior end, 6-8 hepatic caeca secrete digestive enzymes and absorb nutrients. The midgut is the primary site of chemical digestion and absorption. The hindgut, comprising the ileum, colon, and rectum, is crucial for water reabsorption before waste expulsion.

The circulatory system is open, with colourless haemolymph filling the haemocoel. A dorsal, tubular heart with 13 chambers and paired ostia pumps haemolymph anteriorly. Importantly, haemolymph does not transport oxygen. Respiration is via the tracheal system: 10 pairs of spiracles (2 thoracic, 8 abdominal) allow air entry into chitin-lined tracheae, which branch into fine tracheoles that directly supply oxygen to cells.

Excretion is managed by 100-150 fine, yellow Malpighian tubules located at the midgut-hindgut junction. They extract nitrogenous wastes from haemolymph, converting them to uric acid for efficient water conservation. The nervous system includes a supra-oesophageal ganglion (brain), a sub-oesophageal ganglion, and a double ventral nerve cord with three thoracic and six abdominal ganglia, enabling decentralized control.

Reproduction is sexual. Males have a pair of testes, vasa deferentia, an ejaculatory duct, and crucial accessory glands: the mushroom gland (seminal fluid, inner spermatophore layers) and the phallic gland (outer spermatophore layer).

They transfer a spermatophore to the female. Females possess a pair of ovaries, each with 8 ovarioles containing developing eggs. The oviducts lead to a common vagina and the genital pouch.

The spermatheca stores sperm, and collateral glands secrete material to form the protective ootheca, typically housing 14-16 eggs. Remember these specific structures, their numbers, and their precise roles for NEET success.

Prelims Revision Notes

Cockroach Anatomy: NEET Quick Facts

I. Digestive System:

Complete Alimentary Canal: — Mouth to Anus.
Foregut (Stomodaeum): — Lined with cuticle.

* Crop: Large storage sac. * Gizzard (Proventriculus): Muscular, 6 chitinous teeth for grinding.

Midgut (Mesenteron): — Not cuticularized.

* Hepatic Caeca (6-8): At foregut-midgut junction; secrete digestive enzymes (amylase, protease, lipase) and absorb food.

Hindgut (Proctodaeum): — Lined with cuticle.

* Rectum: Reabsorbs water via rectal papillae.

II. Circulatory System:

Type: — Open circulatory system.
Haemocoel: — Body cavity filled with haemolymph.
Haemolymph: — Colourless, contains plasma and haemocytes. **Does NOT transport $ext{O}_2$.** Transports nutrients, hormones, wastes.
Heart: — Dorsal, tubular, 13 funnel-shaped chambers (3 thoracic, 10 abdominal). Each chamber has paired ostia (valved openings).
Alary Muscles (12 pairs): — Help circulate haemolymph.

III. Respiratory System:

Type: — Tracheal system (direct respiration).
Spiracles: — 10 pairs (2 thoracic, 8 abdominal) on lateral sides. Regulate air entry.
Tracheae: — Chitin-lined tubes from spiracles.
Tracheoles: — Finer branches, unlined, directly supply $ext{O}_2$ to cells.

IV. Excretory System:

Main Organs: — Malpighian Tubules (100-150, yellow, filamentous).
Location: — At junction of midgut and hindgut.
Function: — Absorb nitrogenous wastes (potassium urate, uric acid) from haemolymph, convert to uric acid, pass to hindgut. Uricotelic.
Other: — Urate glands (males), fat body, nephrocytes also aid.

V. Nervous System:

Brain: — Supra-oesophageal ganglion (in head, above oesophagus).
Sub-oesophageal Ganglion: — Below oesophagus.
Ventral Nerve Cord: — Double, solid. 3 thoracic ganglia, 6 abdominal ganglia.
Decentralized: — Thoracic ganglia control legs/wings; abdominal ganglia control abdomen/reproduction.

VI. Reproductive System:

Dioecious: — Separate sexes.

* Male: * Testes: Pair, 3-lobed, 4th-6th abdominal segments. * Vasa Deferentia: From testes to ejaculatory duct. * Ejaculatory Duct: Opens via male gonopore. * Mushroom Gland (Utricular Gland): Large, 6th-7th segment. Secretes seminal fluid, forms inner spermatophore layers. * Phallic Gland (Conglobate Gland): Long, club-shaped. Secretes outermost spermatophore layer. * Spermatophore: Sperm packet. * Phallomeres: Chitinous external genitalia.

* Female: * Ovaries: Pair, 2nd-6th abdominal segments. Each with 8 ovarioles (developing ova). * Oviducts: Unite to form common oviduct/vagina. * Spermatheca (Seminal Receptacle): Pair, stores sperm. * Collateral Glands: Pair, secrete material for ootheca. * Genital Pouch (Gynatrium): Contains gonopore, spermathecal pores, collateral gland pores. Ootheca formed here. * Ootheca: Dark brown capsule, 8-10 mm, typically 14-16 eggs.

Vyyuha Quick Recall

To remember the parts of the cockroach digestive system in order: Please Order Crunchy Grilled Hamburgers Made In California Right Away.

Pharynx
Oesophagus
Crop
Gizzard
Hepatic Caeca
Midgut
Ileum
Colon
Rectum
Anus