Cell Junctions

anchoring

Types of Cell Junctions

• In plants:– Plasmodesmata

• In animals:ECM (Extra-cellular Matrix)-– Tight Junctions– Anchoring Junctions– Gap Junctions

Extracellular Matrix

• Sticky layer of glycoprotein holding cells together

• The extracellular matrix (ECM) is the largest component of normal skin and gives the skin its unique properties of elasticity, tensile strength and compressibility.

Tight Junction

• Seals adjacent cells in a narrow band just beneath their surface.

• No leaks.

• EX: blood vessels

Cellular Tight

Junction• Biomembrane II:

• Membrane Junctions

(click on review and

Then animate)

Anchoring Junctions

• Rivet cells together with cytoskeleton structures, but still allow materials to pass along the spaces between cells

Where found

• Where you need to handle stress like:–skin

–Heart

–Intestine

–Concept 4 Review:(desmosomes)

Communicating Junctionsor Gap Junctions

• permit small molecules to shuttle from one cell to another and thus directly link the interior of adjacent cells.

Communicating Junctions“Gap Junctions”

• Where found:–cardiac muscle for heartbeat

–Hormonal stimulation

–Nerves in brain release a neurotransmitter

Gap Junctions

• Concept 4 Review: Gap Junctions (click)

Plasmodesmata

• Channels connecting PLANT CELLS

Plasmodesmata

Plasmodesmata

• Allows small molecules and water to pass between plant cells

Can you identify the cell junctions?

Can you identify the cell junctions?

Tight junction

Anchoring junction

Gap junction