Ch22 L10 Blood Vessels and Circulation

These flashcards cover the main concepts discussed in the lecture about blood vessels and circulation, including their structure, function, and the changes that occur with aging.

What are the three distinct layers of blood vessels called?

Tunica externa (adventicia - areolar loose connective tissue), tunica media (smooth muscle tissue), and tunica intima (simple squamous epithelial).

What is the outermost layer of a blood vessel called?

Tunica adventicia (or tunica externa).

What is the primary function of the tunica media?

It regulates vessel diameter through vessel constriction and dilation.

How do arteries differ from veins in terms of wall thickness?

Arterial walls are much thicker than venous walls.

What is a key structural feature of arteries that enables them to handle higher blood pressure?

A thicker tunica media with more smooth muscle.

What happens to the lumen diameter during vasodilation?

The lumen diameter increases/widens, allowing more blood flow.

What do you observe about the shape of arteries when empty?

Arteries maintain a circular shape.

What distinguishes the endothelial lining of arteries from that of veins?

Arteries have pleated folds in their endothelial lining whereas veins have a flatter lining.

What is the function of the valves found in many veins?

They prevent the backflow of blood.

What are the largest and closest arteries to the heart called?

Elastic arteries.

Which type of artery transitions from elastic to muscular as you move away from the heart?

Muscular arteries.

What role do venules play in the circulatory system?

They collect blood directly from the capillaries.

What is the primary function of capillaries?

They facilitate the exchange of gases, nutrients, and waste between blood and surrounding tissues.

How is blood distributed in the body among veins and arteries?

Approximately 65-70% of total blood volume is found in veins; 30-35% is in arteries.

What significant difference exists between pulmonary and systemic circulation in terms of pressure?

Pulmonary circulation operates at significantly lower pressure than systemic circulation.

Which vessels carry deoxygenated blood to the lungs?

Pulmonary arteries.

How does blood flow into the left atrium?

It returns from the lungs through the left and right pulmonary veins.

What is the function of the Circle of Willis?

It provides collateral circulation to minimize the impact of arterial blockage in the brain.

What does the hepatic portal system do?

It directs blood from the digestive organs to the liver for processing.

What changes occur in the cardiovascular system as a person ages?

Decreased efficiency and elasticity of blood vessels, reduced red blood cell count, and pooling of blood in veins.

What is an aneurysm?

An enlarged blood vessel that balloons outward due to wall weakening.

What happens to the foramen ovale after birth?

It closes and becomes the fossa ovalis.

What key role does the placenta play in fetal circulation?

It provides oxygen and nutrients to the fetus via umbilical arteries and veins.