Structural Organisation and Comparative Anatomy
Structural Organisation and Comparative Anatomy tests tissues, organ systems and comparative features of vertebrate and invertebrate body plans.
Core rules
- Epithelial tissues cover and line; simple epithelium is one layer, stratified is multiple layers, and transitional epithelium lines the urinary bladder.
- Connective tissues include loose connective tissue, dense connective tissue, cartilage, bone and blood; cartilage is avascular.
- Muscle tissue is striated skeletal, striated cardiac or non-striated smooth; smooth muscle cells are spindle-shaped and uninucleate.
- Nervous tissue has neurons and glia; neurons conduct impulses.
- Comparative heart chambers: fish two, amphibians three, reptiles three except crocodiles four, birds and mammals four.
Worked example
A tissue line stretches and recoils in the urinary bladder. It is transitional epithelium because it has multiple layers and umbrella cells that flatten when stretched. The reasoning is location plus function: stratified epithelium protects, while transitional epithelium specifically accommodates urine volume changes.
Traps
- Cartilage lacks blood vessels, so it heals slowly.
- Skeletal muscle is multinucleate; cardiac muscle is branched and intercalated discs are present.
- Frog heart has two atria and one ventricle, not four chambers.
- Blood is connective tissue, not epithelial tissue.