Organ Systems and Frogs Quiz

Study Notes

Multicellular animals have specialized groups of cells called tissues.
Tissues work together to form organs.
Organs work together to form organ systems which perform specific functions.
The division of labor in organ systems allows for efficient and coordinated activities in the body.

Frogs are amphibians, belonging to the class Amphibia of the phylum Chordata.
The common Indian frog species is Rana tigrina.
Frogs are poikilotherms, meaning their body temperature changes with the environment.
Frogs exhibit camouflage with protective coloration.
Frogs enter aestivation during summer to escape heat and hibernation during winter to escape cold.

Multicellular organisms have specialized cells that work together to perform specific functions.
These groups of similar cells with intercellular substances are known as tissues.
Four basic tissue types are found in complex animals: Epithelial, Connective, Muscular, and Neural.

Epithelium is a tissue that covers the surface of the body, body cavities, ducts, and tubes.
It provides a covering or a lining for different parts of the body and has a free surface.
Cells are tightly packed with little intercellular matrix.
Simple epithelium is a single cell layer that functions as a lining for body cavities.
Compound epithelium is composed of two or more layers and provides protective functions.
Simple epithelium is further categorized based on cell structure as:
- Squamous epithelium:
  - Single layer of flattened cells with irregular boundaries.
  - Found in blood vessels and air sacs of lungs.
  - Function: diffusion boundary.
- Cuboidal epithelium:
  - Single layer of cube-like cells.
  - Found in ducts of glands and tubular parts of nephrons in kidneys.
  - Function: secretion and absorption.
- Columnar epithelium:
  - Single layer of tall and slender cells with nuclei at the base.
  - Found in the lining of stomach and intestine.
  - Function: secretion and absorption.
Ciliated epithelium:
- Columnar or cuboidal cells with cilia on their free surface.
- Present on the inner surface of hollow organs like bronchioles and fallopian tubes.
- Function: to move particles or mucus in a specific direction.