Fenestrae Are Structures That

question 1

Multiple Choice

Fenestrae are structures that:

• A) Allow communication between smooth muscle cells otherwise separated by an elastic lamina in the tunica media
• B) Allow for the diffusion of molecules between the cytoplasm of the endothelium and underlying smooth muscle cells
• C) Anchor the bases of valves to the endothelium of lymphatic vessels
• D) Carry electrical impulses in the endocardium of the heart
• E) Penetrate through the cytoplasm of endothelial cells of capillaries

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Definitions:

Thick Filament

A component of the muscle fiber composed primarily of the protein myosin, involved in muscle contraction by interacting with thin filaments.

Sliding Filament Mechanism

The process by which muscles contract, involving the sliding of actin and myosin filaments past each other.

Crossbridge

A structure formed when myosin heads in muscle fibers attach to actin filaments during muscle contraction.

Sarcoplasm

The cytoplasm of a muscle cell, containing organelles, including the mitochondria and sarcoplasmic reticulum.