Chapter 7 : Structural organisation in animals Class 11 | Biology Notes PYQ + PDF Download

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Dropping Complete Notes of Ch-7 Structural Organisation in Animals for NEET 2027 Aspirants

Tegmina to Bidder's Canal - Full PYQ Points Included! 

### *1. Animal Tissues* `1Q Pakka`  

*A. Epithelial Tissue* = Protection, Secretion, Absorption, Excretion

**Type** **Structure** **Location** **NEET Point**

**Simple Squamous** Single layer, Flat cells Blood vessels, Alveoli, Bowman's capsule Diffusion, Filtration

**Simple Cuboidal** Single layer, Cube cells Kidney tubules, Glands Secretion, Absorption

**Simple Columnar** Single layer, Tall cells Stomach, Intestine Absorption + Secretion. Microvilli = Brush border in intestine

**Ciliated Columnar** Cilia on free surface Fallopian tube, Bronchioles Movement of particles/mucus

**Glandular** Columnar/Cuboidal Salivary gland, Pancreas Exocrine = Duct, Endocrine = Ductless

**Compound** Multilayered Skin, Pharynx, Buccal cavity Protection. Skin = Dry, Keratinised

*Cell Junctions*: Tight = Stop leakage. Adhering = Desmosomes = Cementing. Gap = Communication.  

*B. Connective Tissue* = Most abundant. Link & support.  

- *Components*: Cells + Fibres + Ground substance = Matrix.  

- *Loose Connective*:  

    1. *Areolar*: Below skin. Fibroblasts, Macrophages, Mast cells. Support + Repair.  

    2. *Adipose*: Fat cells = Adipocytes. Below skin, Around organs. Store fat, Insulator.  

- *Dense Connective*:  

    1. *Dense Regular*: Tendon = Muscle to Bone. Ligament = Bone to Bone. Collagen fibres parallel.  

    2. *Dense Irregular*: Skin dermis. Collagen fibres irregular.  

- *Specialised Connective*:  

    1. *Cartilage*: Chondrocytes in lacunae. Matrix = Chondroitin salts. Flexible. No blood vessels. Ex: Nose, Ear, Trachea, Joints.  

    2. *Bone*: Osteocytes in lacunae. Matrix = Ca + P salts. Hard. Haversian canal system. Volkmann's canal connects.  

    3. *Blood*: Fluid matrix = Plasma. RBC = Erythrocytes, WBC = Leucocytes, Platelets = Thrombocytes. Fluid connective.  

*C. Muscular Tissue* = Movement

**Type** **Structure** **Location** **Control** **NEET Point**

**Skeletal** Striated, Multinucleate, Cylindrical Attached to bones Voluntary 40-50% body weight

**Smooth** Non-striated, Uninucleate, Spindle Wall of organs, Blood vessels Involuntary Visceral muscle

**Cardiac** Striated, Uninucleate, Branched Heart wall Involuntary Intercalated discs = Communication

*D. Neural Tissue* = Excitability, Conductivity  

- *Neuron* = Structural & functional unit. Cyton + Dendrites + Axon.  

- *Neuroglia* = 50% of neural volume. Protect & support neurons.  

- *Types*: Myelinated = Cranial nerves. Non-myelinated = Autonomic nerves.  

### *2. Organ & Organ System*  

- *Tissue* → *Organ* = Group of tissues. Ex: Stomach = Epithelial + Muscular + Connective + Neural.  

- *Organ System* = Group of organs. Ex: Digestive system.  

- *NEET Point*: Complexity increases: Cells → Tissue → Organ → Organ system → Organism.  

### *3. Cockroach = _Periplaneta americana*_ `1-2Q Fix`  

- *Phylum*: Arthropoda. *Class*: Insecta.  

- *Habit*: Nocturnal, Omnivorous, Cursorial = Running. Uricotelic.  

- *Morphology*:  

    1. *Body*: Head + Thorax + Abdomen. Exoskeleton = Chitin.  

    2. *Head*: Triangular, Hypognathous = Mouth downwards. Compound eyes + Antennae + Mouthparts = Biting & Chewing type.  

    3. *Thorax*: Prothorax, Mesothorax, Metathorax. 3 pairs legs + 2 pairs wings. Forewings = Tegmina = Leathery. Hindwings = Membranous = Flight.  

    4. *Abdomen*: 10 segments. 10th segment in both sexes bears anal cerci. Males = Anal styles also in 9th segment.  

- *Anatomy*:  

    1. *Digestive System*: Alimentary canal = Mouth → Pharynx → Oesophagus → Crop = Storage → Gizzard = Proventriculus = Grinding = 6 teeth + Circular muscles → Midgut = Hepatic caecae = 6-8 = Secretion → Hindgut → Malpighian tubules = 100-150 = Excretion → Rectum → Anus.  

    2. *Circulatory System*: Open type. Blood = Haemolymph. Heart = 13 chambered, dorsal. Alary muscles help circulation. Blood without haemoglobin = No respiration role.  

    3. *Respiratory System*: Tracheal system. 10 pairs spiracles = 2 Thoracic + 8 Abdominal. Trachea → Tracheoles → Cells.  

    4. *Excretory System*: Malpighian tubules. Uricotelic = Uric acid. Also fat body, nephrocytes, urecose glands.  

    5. *Nervous System*: Brain = Supra-oesophageal ganglion + Sub-oesophageal ganglion + Double ventral nerve cord + 3 Thoracic + 6 Abdominal ganglia.  

    6. *Sense Organs*: Antennae, Eyes, Maxillary palps, Labial palps, Anal cerci. Compound eye = 2000 ommatidia = Mosaic vision.  

    7. *Reproductive System*:  

          - *Male*: Testes → Vas deferens → Seminal vesicle → Ejaculatory duct. Accessory glands = Mushroom gland + Phallic gland. External genitalia = Male gonapophysis. Spermatophores formed.  

          - *Female*: Ovaries = 2, 8 ovarioles each → Oviduct → Vagina. Spermatheca = Store sperms. Collaterial glands = Form ootheca. External genitalia = Female gonapophysis.  

          - *Fertilization*: Internal. Ootheca = Egg case = 9-10 eggs. 14-16 ootheca in life. Nymph = No wings, Moults 13 times to become adult = Paurometabolous development.  

### *4. Frog = _Rana tigrina*_ `1Q Aata Hai`  

- *Phylum*: Chordata. *Class*: Amphibia.  

- *Habit*: Amphibious, Carnivorous, Poikilothermic = Cold-blooded, Ureotelic, Hibernation + Aestivation.  

- *Morphology*: Head + Trunk. No neck, tail. Moist skin without scales. Tympanum = Ear. Eyes with nictitating membrane. Webbed feet for swimming.  

- *Anatomy*:  

    1. *Digestive System*: Mouth → Buccal cavity → Pharynx → Oesophagus → Stomach → Duodenum = Bile + Pancreatic juice → Ileum → Rectum → Cloaca. Liver + Pancreas present.  

    2. *Respiratory System*: Cutaneous = Skin in water, Buccopharyngeal = On land, Pulmonary = Lungs = 1 pair, poorly developed.  

    3. *Circulatory System*: Closed type. Heart = 3 chambered = 2 Auricles + 1 Ventricle. Sinus venosus + Truncus arteriosus present. RBC = Nucleated.  

    4. *Excretory System*: Kidneys = Mesonephric. Ureters open in cloaca. Urinary bladder present. Ureotelic.  

    5. *Nervous System*: Brain = Forebrain + Midbrain + Hindbrain. 10 pairs cranial nerves.  

    6. *Reproductive System*:  

          - *Male*: Testes = Yellow, adhered to kidneys by mesorchium. Bidder's canal. No copulatory organ.  

          - *Female*: Ovaries + Oviducts open in cloaca.  

          - *Fertilization*: External in water. Development = Indirect. Larva = Tadpole. Metamorphosis by thyroxine.  

### *5. Earthworm = _Pheretima posthuma_ - Extra for NEET*  

- *Phylum*: Annelida. *Habit*: Terrestrial, Nocturnal, Burrowing.  

- *Body*: 100-120 segments. Clitellum = Glandular tissue = 14-16 segments. Prostomium = Sensory.  

- *Setae*: S-shaped, Locomotion. Absent in 1st, last, clitellum.  

- *Digestive*: Typhlosole = Internal fold in intestine = Increase absorption.  

- *Circulatory*: Closed. Blood = Haemoglobin dissolved in plasma. 4 pairs hearts.  

- *Excretory*: Nephridia = 3 types. Septal = Integumentary = Pharyngeal.  

- *Nervous*: Ganglia + Double ventral nerve cord.  

- *Reproductive*: Hermaphrodite but cross-fertilization. Cocoon formation in clitellum.  

### *6. Last 5 Year PYQ One Liners* `Ratta Maar Le`  

1. *Tegmina* = Forewing of cockroach = Leathery = NEET 2024, 2021.  

2. *Malpighian tubules* = Cockroach = Excretion = Uricotelic = NEET 2023, 2020.  

3. *Hepatic caecae* = Cockroach = 6-8 = Secretion = NEET 2022.  

4. *Open circulatory system* = Cockroach = Arthropods = NEET 2021.  

5. *3-chambered heart* = Frog = 2 Auricle + 1 Ventricle = NEET 2020.  

6. *Bidder's canal* = Male frog = Carry sperms = NEET 2019.  

7. *Nictitating membrane* = Frog = Eye protection in water = NEET 2018.  

8. *Anal styles* = Male cockroach only = 9th segment = NEET 2024.  

9. *Compound epithelium* = Skin, Buccal cavity = Protection = NEET 2017.  

10. *Intercalated discs* = Cardiac muscle = Communication = NEET 2023.  

11. *Uricotelic* = Cockroach = Uric acid = NEET 2016.  

12. *Mosaic vision* = Cockroach = Compound eye = NEET 2022.  

13. *Typhlosole* = Earthworm = Increase absorption = NEET 2019.  

14. *Haversian system* = Mammalian bone = NEET 2018.  

*Diagrams for NEET*: Cockroach - Alimentary canal, Male/Female reproductive system. Frog - Digestive system, Heart. Tissue types.