Ch.15 The Cytoskeleton

What is the Cytoskeleton?

Network of Proteins that Extends throughout the cytoplasm and the nucleus.

What is the function of the cytoskeleton?

Cell shape and structural integrity, cell movement, cell adhesion, intracellular traffic, force, and cell division.

What are the three types of cytoskeleton?

Microtubules, actin filaments, and intermediate.

What are intermediate filaments?

Are rope-like fibers.

What is the most stable and durable of all cytoskeletal fibers.

Intermediate Filaments

Where do intermediate filaments extend across?

Across cytoplasm and inside the nucleus.

Subunits of intermediate filaments?

A large and diverse family of proteins

Functions of intermediate filaments?

Withstand mechanical, cell adhesion.

What is included in intermediate filaments?

Cytoplasmic keratins and nuclear lamina

What is cytoplasmic keratins?

In connective tissues, muscle cells, glia cells, and neurons.

What is the nuclear lamina:

A network beneath the nuclear envelope.

The keratin filaments in ______________ extends across the cytoplasam and connect cells to each other.

What effect does keratin filaments in epithelial cells have on the stretching capabilities of a sheet of cells?

Can be stretched and remain unharmed.

What happens if no keratin filaments and junctions were present?

The cells would rupture if the epithelium were stretched.

What are desmosomes?

Junctions between the cytoskeletons of epithelial cells.

What do desmosomes connect?

Keratins (intermediate filaments) with cadherins (membrane proteins).

In hemidesmosomes, _________, also membrane proteins, connect the keratin filaments to the ______________, part of the extracellular matrix.

Integrins, basal lamina.