Histology: Circulatory System

Front 1

What are the three layers of an artery?

Back 1

1. Tunica intima
2. Tunica media
3. Tunica adventitia

Front 2

What is in the Tunica Intima?

Back 2

1. Endothelium
2. Basal lamina
3. Subendothelial connective tissue
4. Internal elastic lamina

Front 3

What is in the Tunica Media?

Back 3

1. Smooth muscle layer
2. External elastic lamina

Front 4

What is in the Tunica Adventitia?

Back 4

1. Loose connective tissue

Front 5

What vessels feed blood vessels?

Back 5

Vasa vasorum

Front 6

What cell type forms the elastic fibers in the tunica media?

Back 6

Smooth muscle fibers (not fibroblasts!)

Front 7

On a histological slide, what are some visual differences between arteries and veins?

Back 7

Artery is thicker and will appear round.
Vein will appear irregular.
Blood will more often be found in the vein rather than the artery.

Front 8

What are the layers of a capillary?

Back 8

Only endothelium.

Front 9

What type of epithelium is the endothelium of capillaries, arteries, and veins?

Back 9

Simple squamous epithelium.

Front 10

What is the diameter of a capillary?

Back 10

One cell thick, roughly 10uM.

Front 11

Name the types of arteries

Back 11

1. Elastic arteries
2. Muscular arteries
3. Arterioles

Front 12

Name an elastic artery

Back 12

1. Aorta and major branches
2. Iliacs

Front 13

What are the largest arteries in the body?

Back 13

Elastic arteries

Front 14

What is the most prominent feature of elastic arteries?

Back 14

Thick elastic tunica media that does not show internal or external elastic lamina layers.

Front 15

What propels blood through an elastic artery?

Back 15

Contraction action after expansion.

Front 16

What is Marfan's syndrome?

Back 16

A defect in the fibrillin gene. Prone to aneurism and dissection of elastic arteries.

Front 17

What are some prominent features of muscular arteries?

Back 17

1. Thick tunica media (Smooth muscle layer)
2. Distinct internal and external elastic lamina

Front 18

Describe an arteriole

Back 18

1. If you can see the whole structure on a histological slide, it is an arteriole.
2. Tunica adventitia is only a few layers thick.

Front 19

Name the artery that feeds into the capillary bed

Back 19

Metarteriole

Front 20

Name the different types of capillaries

Back 20

1. Continuous
2. Fenestrated
3. Sinusoidal

Front 21

Name the characteristic of a continuous capillary

Back 21

Tight junctions between cells

Front 22

Where are continuous capillaries found?

Back 22

1. nerves
2. muscles
3. connective tissue

Front 23

Name the characteristic of a fenestrated capillary

Back 23

Have small windows with diaphragms.

Front 24

Where are fenestrated capillaries found?

Back 24

In the pancreas and endocrine glands, intestines, and glomerulus

Front 25

Name the identifying characteristic of sinusoidal capillaries and where they are found.

Back 25

They have large holes and are the largest capillaries (30uM) and are found in the spleen, liver, and bone marrow.

Front 26

Describe the innervation of blood vessels.

Back 26

Parasympathetic and sympathetic innervation. Nerves stimulate the outmost layer and the gap junctions allow communication of the signal throughout the vessel (tunica media). Epinephrine is the NT.

Front 27

What is arteriovenous anastomosis?

Back 27

Artery goes directly to the vein, or through a venous plexus to the vein. Capillaries are bypassed. Heat conserved.

Front 28

What do metarterioles do?

Back 28

Regulates amount of blood going into the true capillaries, where heat is lost.

Front 29

How does blood get to veins?

Back 29

1. Through capillaries
2. Through AV anastomosis

Front 30

Name the layers of a vein

Back 30

1. Tunica intima
2. Tunica media
3. Tunica adventitia

Front 31

What is in the tunica intima layer in a vein?

Back 31

1. Endothelium
2. Basal lamina
3. Subendothelial connective tissue
4. Internal elastic lamina

Front 32

What is in in the tunica media layer of a vein?

Back 32

1. smooth muscle
2. fibroelastic connective tissue

This is a very thin layer.

Front 33

What is in the tunica advantitia layer of a vein?

Back 33

1. Collagenous, connective tissue
2. Fibroblasts
3. Elastic fibers
4. Smooth muscle
5. Vasa vasorum.

Front 34

What are the layers of the heart?

Back 34

1. Endocardium
2. Myocardium
3. Epicardium (or visceral pericardium)

Front 35

What is the function of lymphatic ducts in peripheral tissue?

Back 35

Cells and membranes are leaky. Fluid goes into the interstitial fluid. Lymphatic ducts have a blind cap with open valves (flaplike).

Front 36

What is lymphadema?

Back 36

Blockage of lymph ducts that prevent drainage. Causes swelling

Front 37

What are the characteristics of lymph vessels?

Back 37

1. Thin walled
2. Will have white blood cells
3. Larger than a capillary
4. Only have a single cell layer

Front 38

What is a pericyte?

Back 38

AKA Rouget cell or mural cell.
Is a mesenchymal-like cell, associated with the walls of small blood vessels. Undifferentiated cell, it serves to support these vessels, but it can differentiate into fibroblasts, smooth muscle cells, or macrophages.

Front 39

Identify the structures in this image

Back 39

Vein and Arteriole

Front 40

Identify the structure

Back 40

Muscular artery

Front 41

Identify the structure

Back 41

Capillary

Front 42

Identify the vessel

Back 42

Elastic artery

Front 43

Identify the structure

Back 43

Lymph Vessel

Front 44

Identify the cell type and where they would be found

Back 44

Pericyte, associated with the walls of small vessels

Front 45

Identify the cell type and tissue where it can be found

Back 45

Purkinje fibers/cell, found in the myocardium of the heart.

Front 46

Where Weibel-Palade bodies are found?

Back 46

Weibel-Palade bodies are organelles in the endothelial cells.

Front 47

What do Weibel-Palade bodies do?

Back 47

1. von Willebrand factor (vWF), a multimeric protein involved in blood coagulation.

2. P-selectin, which binds to passing leukocytes. This allows leukocytes to bind to the cells lining the blood vessels in a series of steps called the leukocyte adhesion cascade.

Leukocytes transmigrate across the endothelium and enter the surrounding tissue where they can migrate to the site of infection.

Front 48

Explain why the tunica media of large arteries is nourished by the vasa vasorum only during diastole.

Back 48

During systole, the walls of the vessel are under pressure, not allowing blood flow.

Front 49

Explain why the vasa vasorum is more prolific in large veins.

Back 49

Partial oxygen pressure and osmotic pressure is lower than in arteries. More vasa vasorum needed to supply the vessels sufficiently.