Histology-World!

 

 

 

Histology Testbank: Vessels 3a

 

Instructions: For each histology question, pick the one best answer. This histology test bank is also useful for the histology questions on the USMLE (USMLE step 1).

1.
What vessel regulates the amount of blood going into a capillary bed?
a. Capillary
b. Arteriole
c. Venule
d. Elastic artery
e. Muscular artery

Answer: b

Capillaries are very thin walled in order to easily allow the exchange of gases. Gaseous exchange between the blood and tissues occurs at the level of the capillaries.

Arterioles are small branches of arteries with only one or two layers of smooth muscle in the tunica media. Arterioles regulate the amount of blood going into the capillary bed.

Venules are small branches of veins.

Elastic arteries are the arteries leaving the heart and the major branches. The aorta is an elastic artery.

Most of the named arteries are muscular arteries (with the exception of the aorta and the major branches off the aorta). The dividing line between elastic arteries and muscular arteries is not clear cut. However, a pronounced internal elastic membrane and external elastic membrane are distinguishing characteristics of muscular arteries.

Histology hint from Sarah Bellham: Elastic arteries also have an internal elastic membrane. However, there is so much elastic material in the tunica intima of an elastic artery, that a single, discrete internal elastic membrane is not visible.

2.
What is the aorta?
a. Capillary
b. Arteriole
c. Venule
d. Elastic artery
e. Muscular artery

Answer: d

Capillaries are very thin walled in order to easily allow the exchange of gases. Gaseous exchange between the blood and tissues occurs at the level of the capillaries.

Arterioles are small branches of arteries with only one or two layers of smooth muscle in the tunica media. Arterioles regulate the amount of blood going into the capillary bed.

Venules are small branches of veins.

Elastic arteries are the arteries leaving the heart and the major branches. The aorta is an elastic artery.

Most of the named arteries are muscular arteries (with the exception of the aorta and the major branches off the aorta). The dividing line between elastic arteries and muscular arteries is not clear cut. However, a pronounced internal elastic membrane and external elastic membrane are distinguishing characteristics of muscular arteries.

Histology hint from Sarah Bellham: Elastic arteries also have an internal elastic membrane. However, there is so much elastic material in the tunica intima of an elastic artery, that a single, discrete internal elastic membrane is not visible.

3.
What are most of the named arteries in the body?
a. Capillary
b. Arteriole
c. Venule
d. Elastic artery
e. Muscular artery

Answer: e

Capillaries are very thin walled in order to easily allow the exchange of gases. Gaseous exchange between the blood and tissues occurs at the level of the capillaries.

Arterioles are small branches of arteries with only one or two layers of smooth muscle in the tunica media. Arterioles regulate the amount of blood going into the capillary bed.

Venules are small branches of veins.

Elastic arteries are the arteries leaving the heart and the major branches. The aorta is an elastic artery.

Most of the named arteries are muscular arteries (with the exception of the aorta and the major branches off the aorta). The dividing line between elastic arteries and muscular arteries is not clear cut. However, a pronounced internal elastic membrane and external elastic membrane are distinguishing characteristics of muscular arteries.

Histology hint from Sarah Bellham: Elastic arteries also have an internal elastic membrane. However, there is so much elastic material in the tunica intima of an elastic artery, that a single, discrete internal elastic membrane is not visible.

4.
Which structure contains pores?
a. Continuous capillaries
b. Fenestrated capillaries
c. Sinusoidal capillaries
d. AV anastomoses
e. Venous sinus

Answer: b

A characteristic of continuous capillaries is that things are transported across the epithelium via pinocytotic vesicles.

A characteristic of fenestrated capillaries is the presence of pores or fenestrae.

Sinusoidal capillaries (sinusoids) are wide leaky capillaries. They are found in the liver, spleen, and bone marrow.

An arteriovenous anastomoses (AV anastomoses or AV shunt) is a direct route between arteries and veins. It bypasses the capillary bed.

A venous sinus is a venous space lined by endothelium. A venous sinus surrounding the brain exists which is called the dural sinus.

5.
Which one of the following is a pluripotential cell that is prevalent around post capillary venules?
a. Fibroblast
b. Endothelial cell
c. Pericyte
d. Histiocyte
e. Macrophage

A pericyte is a pluripotential cell that is prevalent around post capillary venules.

6.
Which layer in an artery is also called the tunica adventitia?
a. Tunica intima
b. Tunica media
c. Tunica externa
d. All of the above
e. None of the above

Answer: c

The tunica intima is the innermost layer of a blood vessel. It is lined by endothelium

The tunica media is the middle layer of a blood vessel. The tunica media is primarily smooth muscle.

The tunica externa or tunica adventitia is the outer layer of a blood vessel. In large vessels, the tunica adventitia contains vasa vasorum (blood vessels) and nervi vascularis (nerves).

7.
Which layer in an artery is primarily connective tissue?
a. Tunica intima
b. Tunica media
c. Tunica externa
d. All of the above
e. None of the above

Answer: c

The tunica intima is the innermost layer of a blood vessel. It is lined by endothelium

The tunica media is the middle layer of a blood vessel. The tunica media is primarily smooth muscle.

The tunica externa or tunica adventitia is the outer layer of a blood vessel. In large vessels, the tunica adventitia contains vasa vasorum (blood vessels) and nervi vascularis (nerves).

8.
What type of tissue lines blood vessels?
a. Simple squamous epithelium
b. Simple cuboidal epithelium
c. Simple columnar epithelium
d. Stratified squamous epithelium
e. Transitional epithelium

Answer: a

The lining of a blood vessel is simple squamous epithelium. This lining is called endothelium. Epithelium lines body cavities and surfaces. Simple squamous epithelium is "simple" because it is one cell thick. "Squamous" refers to the fact that the cells are flat.

9.
In which of the following is a venous portal system found?
a. Kidney
b. Liver
c. Muscle
d. Skin
e. Stomach

Answer: b

The normal flow of blood is as follows: artery - arteriole - capillary - post capillary venule -vein. However, exceptions to this pattern of blood flow exist.

The phenomenon when a vein is between two capillary beds is called a venous portal system. An example of this is the hepatic portal system. Another example of a venous portal system is seen in the brain between the hypothalamus and pituitary.

The phenomenon when an arteriole is between two capillary beds is called an arterial portal system. This is seen in the kidney.

10.
What are nervi vascularis?
a. Neuropil
b. Neuroglia
c. Pigmented lesion of a vessel
d. Nerves
e. Blood vessels

Answer: d

Nervi vascularis are nerves of the blood vessels. These are the nerves which supply the vessel wall.