Tissues

Definition of a Tissue

A group of cells with a similar structure and function working together.

Definition of an Organ

An aggregation (group) of different tissues working together to perform a specific function.

Epithelial Tissue (Animal)

Covers the surfaces of the body and internal organs (e.g., the lining of the gut).

Glandular Tissue (Animal)

Produces and secretes substances such as enzymes and hormones.

Muscular Tissue (Animal)

Can contract to bring about movement or churn the contents of the stomach.

Epidermal Tissue (Plant)

Covers the surface of the plant for protection; often waxy to reduce water loss.

Palisade Mesophyll (Plant)

Tissue in the leaf packed with chloroplasts for maximum photosynthesis.

Spongy Mesophyll (Plant)

Tissue in the leaf with large air spaces to allow for rapid gas exchange (CO2 and O2).

Xylem Tissue (Plant)

Transports water and mineral ions from the roots to the leaves.

Phloem Tissue (Plant)

Transports dissolved sugars (food) from the leaves to the rest of the plant.

Meristem Tissue (Plant)

Found at the growing tips of roots and shoots; contains stem cells for growth.

Tissues in the Stomach

Muscular (to churn food), Glandular (to produce digestive juices), and Epithelial (to line the stomach).

Translocation

The movement of dissolved sugars through phloem tissue.

Transpiration

The movement of water and minerals through xylem tissue.

Stomata and Guard Cells

Tissue on the underside of the leaf that controls gas exchange and water loss.

Structure of Xylem

Made of dead cells joined end-to-end to form a hollow tube, strengthened by lignin.

Structure of Phloem

Made of living cells with sieve plates to allow the passage of sugar solution.

Why is Spongy Mesophyll 'spongy'?

The air spaces increase the surface area for the diffusion of gases.

Vascular Bundle

The name for the group of tissues (xylem and phloem) that transport substances around the plant.

Organs of a Plant

The leaf, stem, and roots (all made of different tissues working together).