1.1.2 Cell Biology and Histology of the Vascular System

Question 1

Name the major vessels in the order in which they occur starting from the left ventricle.

Answer 1

Large (elastic) artery, medium (muscular) artery, small (ateriole) artery, capillary, venule, medium/large veins

Question 2

What are the three types of capillaries?

Answer 2

Continuous: (pericytes [modified smooth muscle cells] can occur b/t endothelium and basement membrance)

Fenestrated: pores or fenestrae in endothelium

Discontinuous: gaps b/t endothelial cells

Question 3

What are the 3 major layers of the walls of arteries?

Answer 3

1. Tunica intima (innermost)
2. Tunica media (middle)
3. Tunica externa or adventitia (outermost)

Question 4

How many tunics do veins have?

Answer 4

three tunics

Distinction b/t t. media and t. adventitia often unclear and a distinct internal elastic lamina is usually absent. T. media is thinner than that found in arteries of same diameter.

Question 5

What protein aids in the transcytosis across a continuous capillary?

Answer 5

Caveloin; caveolae and vesicles transport substances through the cytoplasm in a bidirectional pathway

Question 6

Answer 6

When you spend too much time making/studying flashcards and lose all of your gains….

Question 7

Answer 7

Question 8

Answer 8

Question 9

Describe the tunica media.

Answer 9

Concentric layers of smooth muscle, collagen fibers, discontinuous plates of elastic sheaths (external elastic lamina)

Question 10

Answer 10

Question 11

Answer 11

Question 12

What is required for both vasculogenesis and angiogenesis?

Answer 12

Vascular Endothelial Growth Factor (VEGF), VEGF receptors, and angiopoietins (Ang 1 and 2) and its receptor (Tie2)

Question 13

What are some risk factors for atherosclerosis?

Answer 13

LDL levels, diabetes, HTN, age

Question 14

Answer 14

Question 15

Loss of pericytes will have what effect on the BBB?

Answer 15

Increases permeability of BBB in CNS. Pericytes are involved w/ tight junction formation

Question 16

Oxidative stress leads to dysfunction of what type of cells and reduced bioavailability of what molecule?

Answer 16

Endothelial cells and reduced NO bioavailability

Question 17

What is another term from large (elastic) arteries?

Answer 17

Conducting arteries, b/c they conduct blood from heart to the medium-sized ateries

Question 18

What type of capillary is each of these? What are the arrows pointing at?

Answer 18

Question 19

What is another term for arterioles?

Answer 19

Resistance vessels, regulate the distribution of blood to different capillary beds by vasoconstriction and vasodilation (vascular tone)

Question 20

What happens to the walls of large (elastic) arteries during systole? diastole?

Answer 20

systole: walls distend
diastole: recoil

Question 21

Where are each of the types of capillaries found?

Answer 21

Continuous: muscle, brain, thymus, lung

Fenestrated: sites of fluid transport (intestine and kidney)

Discontinuous “sinusoidal”: liver, spleen, BM

Question 22

What are some of the things found in lymphatic system?

Answer 22

Leukocytes, albumin, other proteins, and tissue fluid

Question 23

What are the steps in the formation of an atheroma?

Answer 23

1. Damage of endothelium of an artery, LDL infiltrate
2. Lipids taken up by macrophages in the tunica intima and fibroblasts of the subendothelial space proliferate
3. Macrophages release lipids in the subendothelial space and macrophage-derived cytokines stimulate the production of collagen by proliferating smooth muscle cells
4. Ulceration of the atheroma provides a surface for thrombosis. This condition has catastrophic consequences in coronary atherosclerosis b/c it causes luminal obstruction, leading to infarction and sudden cardiac death

Question 24

What is upregulated by cells in response to hypoxia?

Answer 24

HIF-1 (hypoxia inducible factor)

Question 25

Descibe the cytoplasm and basement membrane of the three types of capillary.

Answer 25

Continuous: both basement membrane and endothelial cells are continuous Fenestrated: continous basement membrane. The endothelial cell has fenestrae w/ or w/o diaphragm. Discontinuous: basement membrane and endothelial cell discontinuous

Question 27

What type of capillary is this? What do the letters represent?

Answer 27

Continuous E: endothelial cells BM: Basement membrane P: nucleus of pericyte F: fibroblast M: tight junction

Question 28

What are some of the factors that lead to oxidative stress?

Answer 28

Diabetes, smoking, HTN, dyslipidemia, obesity, and aging

Question 29

What is the difference b/t vasculogenesis and angiogenesis?

Answer 29

Vasculogenesis: new vascular network Angiogenesis: sprouting from an existing network

Question 30

What stain is this? It allows observer to see wavy and fenestrated elastic lamellae span through the tunica media.

Answer 30

Verhoeff's Stain

Question 31

Describe the tunica intima.

Answer 31

Lining of endothelial cells, subendothelial basement membrane and loose connective tissue, dense layer of elastic fibers (internal elastic lamina)

Question 32

Describe the blood pressure as it passes from the aorta through the vena cava. Also describe the lumen diameter and wall thickness of the aorta, arteries, arterioles, capillaries, venules, veins, and vena cava.

Answer 32

Question 33

What are present in veins to prevent reflux of blood?

Answer 33

Valves

Question 34

What type of capillary?

Answer 34

Fenestrated w/ diaphragm in lower left. Fenestrated w/o diaphragm on right.

Question 35

What are some of the genes/proteins upregulated by HIF-1?

Answer 35

EPO, VEGF, EPO/IGF2, GLUT/glycolytic enzymes

Question 36

Answer 36

Question 37

Answer 37

Question 38

How does the postcapillary venule differ from the capillary?

Answer 38

Resembles continuous capillary but with wider lumen

Question 39

Answer 39

Another term for the small blood vessels is vaso vasorum

Question 40

What is the name for the transport vesicle used in transcytosis?

Answer 40

Caveolae

Question 41

What is another term for medium-sized, muscular arteries?

Answer 41

Distributing ateries, allowing selective distribution of blood to different organs in response to functional needs

Question 42

What is the diameter of a capilliary? Describe how RBCs must pass through capillary.

Answer 42

~ 5-10 um, permitting the passage of ~one RBC at a time

Question 43

Describe the conduction of blood in the arteries.

Answer 43

From the heart to capillaries.

Question 44

Describe the tunica externa (adventitia).

Answer 44

Connective tissue (large vesssels have vasa vasorum, neural tissue [nervi vasorum])

Question 45

Answer 45

Question 46

What is atherosclerosis?

Answer 46

Deposition of fatty material in the wall of the vessel to form a lesion called an atheroma, usually involves large (elastic) arteries

Question 47

How many concentric layers of vascular smooth muscle surround arterioles?

Answer 47

2-5