20.4 Local Blood Flow

What is local blood flow?

The flow of blood through specific tissues at a given time.

Are all capillaries filled at the same time?

No, local blood flow varies and not all capillaries are filled simultaneously.

How is blood flow measured?

In milliliters per minute (mL/min).

Why must blood flow be maintained at a certain level?

To ensure adequate perfusion of tissues.

What is perfusion?

The delivery of blood to tissues.

What factors does local blood flow depend on?

Degree of tissue vascularity, myogenic response, local regulatory factors, and total blood flow.

What is tissue vascularity?

The number of blood vessels in a tissue.

How does tissue vascularity affect blood flow?

More vessels allow greater blood flow.

What is the myogenic response?

The ability of blood vessels to adjust their diameter in response to pressure changes.

What are local regulatory factors?

Chemical and physical signals that alter blood flow based on tissue needs.

How does total blood flow influence local blood flow?

It determines how much blood is available to distribute to tissues.

Why does local blood flow vary?

Because different tissues have different metabolic needs at different times.