Biology · ZoologyZOO 02
Structural Organisation in Animals
Epithelial, connective, muscular, neural tissues; cockroach anatomy
Concept Core
Essential theory — everything NCERT tests on Structural Organisation in Animals
ANIMAL TISSUES — EPITHELIAL
Lines body surfaces, cavities, and organs. No blood supply (avascular). Types: squamous (simple/stratified), cuboidal, columnar (with/without microvilli), ciliated, pseudostratified, transitional (urinary bladder).
Functions: protection, secretion, absorption, filtration.
CONNECTIVE TISSUE
Most abundant tissue. Derived from mesoderm. Has cells in extracellular matrix.
Types: Loose CT (areolar — fills spaces), Dense CT (tendons, ligaments), Specialised: cartilage (chondrocytes), bone (osteocytes), blood (fluid CT), lymph.
Cartilage matrix: chondroitin. Bone: calcium phosphate.
MUSCLE & NEURAL TISSUE
Skeletal muscle: striated, voluntary, multinucleated. Cardiac: striated, involuntary, branched, intercalated discs. Smooth: non-striated, involuntary, spindle-shaped.
Neural tissue: Neurons (excitable) + Neuroglia (supporting). Neuron parts: dendrites, cell body (soma/perikaryon), axon.
COCKROACH ANATOMY
Body: head (6 fused segments), thorax (3: pro/meso/metathorax), abdomen (10 segments). Exoskeleton: chitin.
Digestive: mouth → pharynx → oesophagus → crop → gizzard (grinding) → stomach → intestine → rectum.
Circulatory: open system, haemocoel, 13-chambered heart. Excretory: Malpighian tubules.
COCKROACH — NERVOUS & REPRODUCTIVE
Nervous: double ventral nerve cord, 3 thoracic + 6 abdominal ganglia + brain. Compound eyes (mosaic vision). Tympanal organs for sound.
Male: mushroom gland (accessory). Female: 8 ovarioles per ovary. Oothecae = egg cases. Pheromones for mate attraction.
Fact & Formula Vault
High-yield facts, numbers, and formulas
Tissue Types
Epithelial: avascular, covers surfaces
Connective: vascular (except cartilage)
Muscle: contractile
Neural: excitable, conducts impulse
Connective Tissue
Areolar: loose CT, fills spaces
Tendon: muscle→bone (collagen)
Ligament: bone→bone (elastic)
Cartilage: chondrocytes, avascular
Cockroach Key Facts
13-chambered heart (open circulation)
Malpighian tubules: excretion
Chitin: exoskeleton material
Compound eyes: ~2000 facets (ommatidia)
Worked Examples
NEET-style questions solved step-by-step
EASYWhich tissue lines the urinary bladder?▾
Which tissue lines the urinary bladder?
Transitional epithelium (urothelium). It can stretch as the bladder fills. It is stratified and has unique dome-shaped surface cells.
MEDIUMThe excretory organs of cockroach are:▾
The excretory organs of cockroach are:
Malpighian tubules. They absorb nitrogenous wastes (uric acid) from haemocoel and pour them into hindgut. Cockroach is uricotelic.
HARDCockroach heart has how many chambers and what type of circulation?▾
Cockroach heart has how many chambers and what type of circulation?
13 chambers (3 thoracic + 10 abdominal). Open circulatory system — blood (haemolymph) flows into haemocoel (body cavity), not within closed vessels.
Mistake DNA
Common NEET traps for this chapter
⚠ Striated vs non-striated
Cardiac muscle IS striated but involuntary. Students confuse: striated = voluntary — WRONG for cardiac.
✓ Fix: Striated = skeletal (voluntary) + cardiac (involuntary). Non-striated = smooth.
⚠ Cartilage is avascular
Cartilage has NO blood vessels. Nutrition by diffusion through matrix. Slow healing.
✓ Fix: Bone = vascular. Cartilage = avascular.
⚠ Cockroach chambers
The heart has 13 chambers, NOT 10. (3 thoracic + 10 abdominal = 13)
✓ Fix: Always add: 3 thoracic + 10 abdominal = 13
Chapter Intelligence
Exam data and last-minute strategy
NEET Frequency
1–2 Q/year. Tissue types, cockroach heart chambers, Malpighian tubules, and compound eyes are standard NEET questions.
High-Yield
13-chambered heart. Malpighian tubules = excretion. Transitional epithelium = bladder. Cartilage = avascular (chondroitin matrix). Cardiac = striated + involuntary.
Strategy
Draw cockroach organ system table: system → organs → key feature. For tissues, make a 4-row table with type, cell, matrix, function.
🧪 Practice with Full Mock Tests
7 full-length NEET mocks · 180 Qs · +4/−1 · Mock 1 FREE
Open Mock Tests →
