Chapter 7: Structural Organisation in Animals

Epithelial cells are divided into two broad categories based on structural modification of the cells:

(A) Simple Epithelium and (B) Compound (Stratified) Epithelium

Simple Epithelium: It is the epithelium tissue which has a single layer of the cell. It is further divided into three: Squamous cells, cuboidal cells and columnar epithelium.

Compound (stratified) Epithelium: It is the epithelium tissue which has two or more layers of cells lined together.

Connective tissues have an important role in the binding and connection of different tissues and organs.

They provide structural rigidity support and protection of the body.

They can regenerate

Fibres, cells and matrix are present in connective tissues.

Gamete exchange of earthworms occurs through cross-fertilization and external fertilization.

Two earthworms come closer to each other and they get ventrally attached in the opposite direction.

ii) The copulation process begins and the male genital pore (i.e., papilla) of one earthworm is inserted into the spermathecal pore of the other earthworm.

iii) The earthworm remains mutually close together by the penetration of setae in their bodies.

iv) Sperm and prostatic fluid of the earthworm are exchanged and the spermathecal pore stores the spermathecae.

v. The remains like than for an hour and the sperm and egg passed into cocoon which gets secreted by the clitellar gland present in the 14th to the 16th segment of the earthworm.

Their alimentary canal consists of three parts:

(A) Foregut

(B) Midgut

(C) Hindgut

(A) Foregut: The foregut consists of the mouth in cockroaches. The oesophagus is a narrow tube-like structure which leads to an organ known as a crop. The crop is used to store food materials. It consists of the tongue and hypopharynx

B) Midgut: Midgut is a narrow and short tube-like structure. It has an organ known as gizzard which grinds the food into simpler components.

(C) Hindgut: The hindgut is further divided into three major parts: Ileum, Colon, and Rectum. Malpighian tubules help in the elimination of the nitrogenous wastes and convert them to uric acid.

The anus is the last part of the digestive system of the cockroach.

5. Draw a neat and well-labelled diagram of the male reproductive system of a frog.

We know that for life, certain systems and processes need to function in tandem. Similarly, life has a certain organisational structure, which is dictated by millions of years of evolution.

For instance, a snail and a squid belong to the same phylum – Mollusca. But they evolved and have varied characteristics to adjust to their environment. A squid uses jet propulsion to move around in the ocean. Meanwhile, a snail uses muscular contractions that help it move around slowly. And most land snails have shells that protect them from predators. Squids had shells millions of years ago, but they lost them in favour of features that avoided predators more efficiently.

1. Animal Tissues
   1. Epithelial Tissue
   2. Connective Tissue
   3. Muscle Tissue
   4. Neural Tissue
2. Organ and Organ System
3. Earthworm
   1. Morphology
   2. Anatomy
4. Cockroach
   1. Morphology
   2. Anatomy
5. Frogs
   1. Morphology