Cardiovascular System 2

Question 1

What are the small muscular arteries with 1,2 or 3 layers of smooth muscle?

Answer 1

Arterioles

Question 2

What is the function of an arteriole?

Answer 2

Arterioles are the last small branches of the arterial system and act as control valves through which the flow of blood is regulated into the terminal vascular bed.

Question 3

True of False: In arterioles the internal elastic lamina is absent?

Answer 3

False

In arterioles a small internal elastic lamina (tunica intima level) may be present but the external elastic lamina (tunica media level) is absent.

Question 4

Describe a venule

Answer 4

Characterized by a relatively indistinct tunica media and adventitia. Often have a bigger lumen compared to their wall thickness and are irregularly shaped

Question 5

True or False: Venules collect blood from the terminal vascular bed and gradually coalesce into progressively larger veins?

Answer 5

True

Question 6

True or False: Arterioles are small muscular arteries that most often are found by themselves?

Answer 6

False

Like other larger vessels, you will often see arterioles and venules together side by side or in very close proximity.

Question 7

What is responsible for shunting blood from arterioles to venules without passing through a capillary bed?

Answer 7

Arteriovenous (A-V) anastomoses

Question 8

What are the main characteristics of arteriovenous anastomoses?

Answer 8

1. Smooth muscle adjacent to the tunica intima which is oriented longitudinally and has an epithelioid appearance
2. Remainder of the tunica media is comprised of circularly arranged smooth muscle
3. Can open or close to regulate blood flow to certain capillary beds

Question 9

List three locations where arteriovenous anastomoses are found and three functions they might perform.

Answer 9

Skin, Digestive tract, and erectile tissue of male reproductive tract

Function in regulation of blood pressure, thermoregulation, and erection

Question 10

What is a pericyte and where is it found?

Answer 10

Pericytes are pluripotent cells capable of differentiating into fibroblasts, smooth muscle cells and mast cells. They are associated with vessels of the terminal vascular bed and located within the vessel’s basement membrane.

Question 11

What is the term for the last little artery comprised of a single layer of smooth muscle?

Answer 11

Terminal arteriole

Question 12

In a terminal arteriole a ____ is present while the ____ is absent.

Answer 12

tunica media is present (composed of a single layer of smooth muscle) but the tunica adventitia is absent.

Question 13

What are the simplest members of the vascular system that provide the means by which metabolites gain access to and waste products leave the connective tissue.

Answer 13

Capillaries

Question 14

Capillaries are usually big enough to let ____ red blood cells pass.

Answer 14

Only 1 red blood cell at a time can pass through a capillary

Question 15

What are the 4 types of capillaries?

Answer 15

1. Continuous (non-fenestrated)
2. Fenestrated
3. Discontinuous
4. Lymph

Question 16

What type of capillary matches each description:

1. Pores scattered throughout the walls of the endothelium
2. Resemble blood capillaries but carry lymph
3. Wall is fenestrated and the basal lamina is discontinuous or missing
4. No interruptions in the continuity of their endothelial cells

Answer 16

1. Fenestrated capillary
2. Lymph capillary
3. Discontinuous capillary-sinusoids
4. Continuous capillary

Question 17

In a continuous capillary the wall is _____ and _____ juntions are present. In muscle _____ vessicles are present and aid in transport of materials across the wall.

Answer 17

uniform in thickness

tight juctions

pinocytotic

Question 18

A type of continuous capillary that forms the blood brain barrier and lacks pinocytotic vesicles

Answer 18

Neural capillary

Question 19

In a fenestrated capillary the wall is _____ where _____ is absent and _____ are present for movement of materials.

Answer 19

Wall is attenuated where cytoplasm is absent and pores or fenestrae are present for moving materials.

Question 20

What type of tissues are fenestrated capillaries associated with?

Answer 20

Metabolically active tissues such as kidney and intestine.

Question 21

What common characteristic do continuous and fenestrated capillaries share?

Answer 21

Intact basement membrane

Question 22

True or False: A discontinuous capillary will have a small lumen (only one RBC at a time can pass) and thick walls?

Answer 22

False-the lumens are large enough to allow passage of several RBCs at a time and the vessels are thin walled

Question 23

Where would you find discontinuous capillaries?

Answer 23

Endocrine glands and organs that have phagocytic cells associated with the endothelium, such as the liver.

Question 24

What are two primary differences between lymph capillaries and blood capillaries?

Answer 24

1. Lymph capillaries lack a basal lamina and pericytes
2. Lymph capillaries end blindly whereas blood capillaries have an arteriole and venous end

Question 25

Where would lymph capillaries predominate and what function to they have?

Answer 25

Prominent in the gut where they collect fatty acids and glycerol for transport to the blood.

Question 26

What is the most permeable part of the terminal vascular bed and the site of an inflammatory response?

Answer 26

Postcapillary venule

Question 27

True or False: Postcapillary venules can have associated pericytes?

Answer 27

True

Question 28

What is the main difference between a capillary and a postcapillary venule?

Answer 28

The structure is similar but the lumen of a postcapillary venule can accomodate 2 to 3 red blood cells.

Question 29

What are blood sinuses and where are they located?

Answer 29

Blood sinuses are large, round to irregularly shaped vessels that usually lack smooth muscle. They occur in erectile tissue and are for pooling of blood.

Question 30

What is the venous portal system and give an example of one?

Answer 30

The venous portal system is a capillary bed situated between two veins. The portal vein is the venous drainage for the GI tract which supplies the hepatic capillary bed and sinusoids. These empty into the hepatic veins.

Question 31

What is the arterial portal system and give an example?

Answer 31

The arterial portal system is a capillary bed situated between two arterioles. In the kidney the afferent arteriole supplies the renal capillary bed which empties into the efferent arteriole.

Question 32

Arrange from largest to smallest:

Capillary

Artery

Arteriole

Answer 32

Artery is largest

Arteriole is a small artery