11/24/2014 Microscopic Anatomy Blood Vessels II Thomas Poole

Question 1

What is the average diameter of a capillary

Answer 1

5-10 microns

Question 2

What is the average length of a capillary?

Answer 2

0.05 - 1 mm depending on the organ

Question 3

Name the intermediate filaments that provide structural support to endothelial cells.

Answer 3

Desmin

Vimentin

Question 4

What kinds of junctions to endothelial cells make?

Answer 4

Tight junctions or gap junctions, depending on the organ

Question 5

What “stuff” do endothelial cells produce?

Answer 5

Collagens, is types I, II, IV and V
Fibronectin
Laminin
Coagulants
Anticoagulants

Question 6

What cells share the basal lamina with the endothelial cells?

Answer 6

Pericytes

Question 7

Pericytes are what shape?

Answer 7

Stellate

Question 8

Pericytes can serve what function after injury?

Answer 8

They can be stem cells for endothelial cells and smooth muscle cells.

Question 9

What capillaries have tight junctions?

Answer 9

Continuous capillaries (muscle, nervous, connective tissue, exocrine pancreas)

Question 10

Where are fenestrated capillaries located?

Answer 10

Pancreas, intestine, endocrine glands

Question 11

A special type of fenestrated capillaries with no diaphragm is located where?

Answer 11

Renal glomerulus

Question 12

What is a diaphragm of the capillary?

Answer 12

In fenestrated capillaries, except in the renal glomerulus, the windows in the capillaries have little caps.

Question 13

About how big is a capillary fenestra?

Answer 13

60-80nm in diameter

Question 14

What kind of capillaries are found in endocrine glands, liver, bone marrow and spleen?

Answer 14

Sinusoidal capillaries:
Discontinuous in liver and bone marrow;
Venous sinusoids in spleen

Question 15

What is the difference between fenestrated and sinusoidal capillaries?

Answer 15

In sinusoidal capillaries, the diaphragms are much larger, as to be leaky.

Question 16

What are the three main methods of transport across a capillary wall?

Answer 16

1. Fenestrations
2. Pinocytosis
3. Trans-Golgi network vesicles
   * *2 and 3 are examples of transcytosis

Question 17

There are two distinct pore systems in endothelial cells: small (9-11nm) and large (50-70nm). The small system is through to be gaps that allow for what kind of transport?

Answer 17

Water and small hydrophilic vesicles

Question 18

T/F: Arteries are more numerous in the body then veins.

Answer 18

False. Veins are both larger and more numerous in the body, carrying up to 70% of the body’s blood at any given time.

Question 19

Why do veins have more extensive vasa vasorum and lymphatics?

Answer 19

Because they see less oxygenated blood and need another way to receive nutrients.

Question 20

__1__ contain more collagen and less elastic substance and smooth muscle than __2__.

Answer 20

1. Veins

2. Arteries

Question 21

Veins owe most of their thickness to what outermost layer of their structure?

Answer 21

Adventitia

Question 22

What forms the small valves in certain small and medium veins?

Answer 22

Intima infolding, with an elastic tissue core.

Question 23

In large veins, what structural tissue element is often missing or incomplete?

Answer 23

Media (between intima and adventitia)

Question 24

Large veins contain a continuous endothelium and basal lamina, but no ____

Answer 24

internal elastic lamina

Question 25

Large vein adventitia contains what important structures?

Answer 25

1. Vasa vasorum
2. Lymphatics
3. Collagen and elastic fibers
4. Smooth muscle, longitudinally-oriented

Question 26

In arteries, which section is largest, the intima, media or adventitia?

Answer 26

Media

Question 27

In small and medium veins, in what direction does smooth muscle arrange itself? What layer is smooth muscle found in?

Answer 27

Smooth muscle is found in the media in small and medium veins, and runs circumferentially.

Question 28

What types of vessel are the preferred location for leukocyte emigration?

Answer 28

Venules

Question 29

What are the two types of venules?

Answer 29

1. Pericytic venules

2. Muscular venules

Question 30

Where are pericytic venules found?

Answer 30

Post capillary venules that resemble large capillaries, about 10-15 microns in diameter.

Question 31

Muscular venules received blood from:

Answer 31

pericytic venules and accompanying arterioles

Question 32

Do muscular venules have smooth muscle?

Answer 32

Yes, 1-2 circular layers of smooth muscle in the media.

Question 33

What is a portal system?

Answer 33

A portal system carries blood from one capillary bed to another, ie. hepatic portal system.

Question 34

Arteriovenous anastomoses are direct connections between arterioles and venules. Smooth muscle cells form a ___ that regulates blood flow and allows a bypass of the capillary bed.

Answer 34

sphincter

Question 35

Large lumens, thin walls, irregular shape, extensive branching. These are all characteristics of?

Answer 35

The lymphatic vessels

Question 36

How are lymphatic capillaries similar to regular capillaries?

Answer 36

They aren’t, really. They have a discontinuous basal lamina, and are held open by elastic anchoring filaments.

Question 37

What is a Weibel-Palade body?

Answer 37

Weibel–Palade bodies are the storage granules of endothelial cells, the cells that form the inner lining of the blood vessels and heart. They store and release two principal molecules, von Willebrand factor and P-selectin, and thus play a dual role in hemostasis and inflammation.