Chapter 19 Practice for Test!

All capillary beds are continuously perfused with blood.

False

Osmotic pressure is created by the presence in a fluid of small diffusible molecules that easily move through the capillary membrane. T/F

False

The outermost layer of a blood vessel is the tunica intima. T/F

False

The pancreas is an example of an organ with arteries that do not anastomose. T/F

False

The thick-walled arteries close to the heart are called muscular arteries. T/F

False

Vasodilation is a widening of the lumen due to smooth muscle contraction. T/F

False

Veins carry only oxygen deficient blood. T/F

False

Site where the blood pressure is greatest.

Large Arteries

Site where the velocity of blood flow is fastest.

Large Arteries

Site where blood pressure is lowest.

Large Veins

Site where the blood volume is greatest.

Large Veins

why the arterioles are known as resistance vessels?

The contraction and relaxation of the smooth muscle in their walls can change their diameter.

A precapillary sphincter is a cuff of smooth muscle that regulates the flow of blood into the capillaries. T/F

True

An increase in blood viscosity will cause an increase in peripheral resistance. T/F

True

Arteries supplying the same territory are often merged with one another, forming arterial anastomoses. T/F

True

What type of vessel has relatively little smooth muscle or elastin in the tunica media, a large lumen (average of 5.0 mm in diameter), and thin walls (average of 0.5 mm)?

Vein

Which of the following is true about veins? a) Veins have valves; arteries do not. b) Veins carry blood away from the heart, while arteries carry blood to the heart. c) Veins are more muscular than arteries. d) Veins have a smaller diameter lumen than arteries.

a) Veins have valves; arteries do not

Which of the following is the most significant source of blood flow resistance? a) blood vessel diameter b) total blood vessel length c) blood viscosity d) blood vessels type

a) blood vessel diameter

Gas and nutrient exchanges between the blood and tissues take place at the __________.

capillaries

Which capillaries are the most common in the body?

continuous capillaries

The most common type of blood capillary is the ________.

continuous capillary

The arteries that are also called distributing arteries are the ________.

muscular arteries

The influence of blood vessel diameter on peripheral resistance is ________.

significant because resistance is inversely proportional to the fourth power of the vessel radius

Leaky capillaries found in the bone marrow are called __________.

sinusoidal capillaries

Which of the following is not true regarding fenestrated capillaries? a)Fenestrated capillaries in endocrine organs allow hormones rapid entry into the blood. b)Fenestrated capillaries in the small intestine receive nutrients from digested food. c)Fenestrated capillaries are essential for filtration of blood plasma in the kidney. D)Fenestrated capillaries form the blood-brain barrier.

D)Fenestrated capillaries form the blood-brain barrier.

The aorta is an example of a(n) __________.

elastic artery

Which type of vessel contains elastin in all three tunics to allow the vessel to expand and recoil as the heart ejects blood?

elastic artery

What type of tissue is found in the walls of the arteries but not in the walls of capillaries and venules?

elastic tissue

Peripheral resistance ________.

increases as blood viscosity increases

What type of vessel has relatively more smooth muscle and less elastic tissue?

muscular artery

The arteries that directly feed into the capillary beds are called ________.

arterioles

What is the outermost layer of the blood vessel wall for an artery or vein?

tunica externa

Histologically, the ________ is squamous epithelium supported by a sparse connective tissue layer.

tunica intima

Which layer of the typical blood vessel is constructed from simple squamous epithelium?

tunica intima

What layer can change blood vessel diameter by vasodilation and vasoconstriction?

tunica media

Which tunic of an artery is most responsible for maintaining blood pressure and continuous blood circulation?

tunica media

Which statement best describes arteries?

All carry blood away from the heart.

Site that is the major determinant of peripheral resistance.

Arterioles

Site where resistance to blood flow is greatest.

Arterioles

Site where exchanges of food and gases are made.

Capillaries

Site where the velocity of blood flow is slowest.

Capillaries

Select the correct statement about blood flow. a) It is measured in mm Hg. b) Blood flow through the entire vascular system is equivalent to cardiac output. c) It is relatively constant through all body organs. d) It is greatest where resistance is highest.

b) Blood flow through the entire vascular system is equivalent to cardiac output.

Varicose veins seen in the superficial veins of the legs are unsightly and often treated by surgically removing them. However, even without these veins being present, the return of all blood toward the heart from the legs is not diminished primarily because ______.

blood can still return via the deep veins

Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of ________.

capillaries

Which of the following is true about veins? a) Veins have a small lumen in relation to the thickness of the vessel wall. b) Venous valves are formed from the tunica media. c) Up to 35% of total body blood is in venous circulation at any given time. d) Veins are called capacitance vessels or blood reservoirs.

d) Veins are called capacitance vessels or blood reservoirs.

Modified capillaries that are lined with phagocytes are called ________.

sinusoids