How This Chapter Is Asked in NEET

Structural Organisation in Animals is short, factual and highly predictable. Every question is one of four shapes: name the tissue from its description, name the location or the cell, give the number, or spot the odd one out. Nothing has to be worked out, which means every mark here is decided before you enter the hall.

The traps repeat, and they are always the same six:

  • The two seasons swapped. Aestivation is summer sleep, hibernation is winter sleep.
  • Tendon and ligament swapped. Tendon - muscle to bone. Ligament - bone to bone.
  • The heart vessels swapped. Sinus venosus goes INTO the right atrium. Conus arteriosus comes OUT of the ventricle.
  • The two portal systems swapped. Hepatic - liver and intestine. Renal - kidney and lower body.
  • Cartilage and bone cells swapped. Chondrocytes - cartilage. Osteocytes - bone, in lacunae.
  • Human numbers offered for frog facts. The frog has ten pairs of cranial nerves and three heart chambers; twelve and four are the human answers, put there on purpose.

One more habit that pays here. In a "which is NOT" question, the wrong option is almost never invented - it is a real structure borrowed from a neighbouring system. A bile duct in an excretory list, a tympanum in an endocrine list, an optic lobe in a fore-brain list. Ask "which system does this actually belong to" rather than "have I heard of this".

Before You Start

Give yourself 40 minutes for 40 questions and look nothing up. Mark every question where you were choosing between two options rather than certain - those marked questions, not the wrong ones, are your revision list.

The facts most likely to decide your score:

Levels. Cells - tissues - organs - organ systems. A tissue is a group of cells along with intercellular substances performing one or more functions. Four basic tissue types - epithelial, connective, muscular, neural.

Epithelia. Squamous - flat, blood vessel walls and air sacs, diffusion boundary. Cuboidal - ducts of glands and tubular parts of nephrons, secretion and absorption. Columnar - stomach and intestine lining. Ciliated - moves particles or mucus in one direction. Glandular - unicellular goblet cells or multicellular salivary gland; exocrine through ducts, endocrine ductless, hormones into blood. Compound - many layers, protection, on the dry skin surface, buccal cavity, pharynx and ducts of most glands.

Junctions. Tight - stops leaking. Adhering - cements cells. Gap - rapid transfer of ions and molecules.

Connective. Areolar - beneath the skin, support framework. Adipose - stores fat. Dense regular - tendons and ligaments. Cartilage - chondrocytes. Bone - osteocytes in lacunae. Blood - fluid connective tissue, plasma plus cells.

Muscle. Skeletal - bones, striated, voluntary. Smooth - hollow visceral organs, unstriated, involuntary. Cardiac - heart only, striated, involuntary, intercalated discs.

Neural. Neurons conduct; neuroglia support and are more than half the volume.

The frog. Rana tigrina, Amphibia, poikilotherm. Head and trunk, no neck, no tail. Five hind digits, four fore digits. Never drinks water - absorbs through the skin. Male - vocal sacs and copulatory pad. Short canal because carnivore. Cutaneous and pulmonary respiration. Three-chambered heart, pericardium, sinus venosus, conus arteriosus, hepatic and renal portal systems, nucleated RBCs, lymph lacks a few proteins and RBCs. Kidneys, ureters, cloaca, urinary bladder; nephrons; ureotelic. Ten pairs of cranial nerves; fore-, mid- and hind-brain; foramen magnum. Mesorchium, 10 to 12 vasa efferentia, Bidder's canal, urinogenital duct. Ovaries near kidneys with no functional connection. 2500 to 3000 ova, external fertilisation, tadpole, metamorphosis.