Cardiovascular System

Front 1

What are the three layers of the tunica intima?

Back 1

Endothelium: Deep
Subendothelial layer: Middle
Internal Elastic lamina: Superficial

Front 2

What are the three layers of blood vessels deep to superficial?

Back 2

Tunica Intima --> Tunica Media --> Tunica Adventitia

Front 3

What are the characteristics of the Tunica media?

Back 3

Smooth muscle cells
elastic reticular collagenous fibers
external elastic lamina

Front 4

What are the characteristics of the Tunica Adventitia?

Back 4

Collagenous and elastic tissue
vasa vasorum

Front 5

What separates the Tunica Intima from the tunica media?
What separates the Tunica media from the Tunica Adventitia?

Back 5

Internal elastic membrane
External elastic membrane

Front 6

Smooth muscle cells produce all components of _____.

Back 6

tunica media

Front 7

The various types of vessels distinguished on the basis of what?

Back 7

1) thickness of the vascular wall.
2) differences in composition of layers.

Front 8

What are examples of Elastic Arteries?

Back 8

Aorta, pulmonary, common carotid, brachiocephalic, subclavian, common iliac

Front 9

What is the role of elastic arteries?

Back 9

Distend and recoil to facilitate pumping of blood

Front 10

What are the characteristics of elastic arteries?

Back 10

Thick Intima
Media:
-->Lamellae of elastin
-->Smooth muscle
Thin adventitia
Vasa vasorum:
-->Capillaries penetrate into media

Front 11

What are the characteristics of Muscular arteries compared to elastic arteries?

Back 11

Thinner intima
-->Prominent internal elastic lamina
Media:
-->More smooth muscle
(3 - 40 layers)
-->Less elastin
-->External elastic lamina
Thicker adventitia

Front 12

What is the role of Muscular arteries?

Back 12

Contraction helps to maintain BP and movement of blood

Front 13

What is the role of arterioles?

Back 13

Major site of peripheral resistance to blood flow.

Front 14

What are the characteristics of arteriorles?

Back 14

- 40 to 200 microns in diameter.
- Thin, fenestrated internal elastic lamina.
- 1-2 layers of smooth muscle in tunica media.
- Adventitia is thin and ill-defined.

Front 15

What is the component of microcirculation called?

Back 15

Arterioveous anastomoses

Front 16

What do arterioveous anastomoses do?

Back 16

Allow blood to bypass capillaries by providing direct routes between arteries and veins.

Front 17

Where are arterioveous anastomoses commonly found?

Back 17

Commonly found in skin of fingertips, nose, lips, and erectile tissue

Front 18

What opens or closes to regulate the flow of blood across the capillary beds?

Back 18

Pre-capillary sphincters

Front 19

What are innervated by the sympathetic nervous system? What does this allow them to do?

Back 19

Small Arterioles use sympathetic mediated constriction to help slow the flow of blood to the capillary bed.

Front 20

A Preferential or _____ enables _____ blood flow from the arteriole to the post capillary venule

Back 20

Thoroughfare channel, continuous

Front 21

What is a metarteriole?

Back 21

Serves as thoroughfare channel to postcapillary venules
- Bypasses capillary bed
Also as conduit to supply capillary bed
--> The wall is encircled with discontinuous smooth muscle

Front 22

Blood flow through the true capillaries can be _____.

Back 22

Intermittent

Front 23

What are the characteristics of the capillaries?

Back 23

50,000 miles in human body
Consist primarily of thin endothelial cells
Major sites of exchange of gases and metabolites
Average diameter of 9-12 microns

Front 24

Where are Pericytes found?
What do they appear to do?

Back 24

Enclosed in basal lamina of endothelial cells
Appear to be contractile cells

Front 25

What are the three types of capillaries?

Back 25

Continuous
Fenestrated
Discontinuous (sinusoids)

Front 26

What are the characteristics of continuous capillaries?

Back 26

Material traverse endothelia cell via pinocytotic vesicles

Front 27

What are characteristics of Fenestrated capillaries?

Back 27

Perforations (fenestrations) 80-100 nm provide channels across capillary wall
Have pinocytotic vesicles
May have a nonmembranous diaphragm across openings (remnant of glycocalyx)

Front 28

What are the characteristics of discontinuous capillaries?

Back 28

Large lumen (30 - 40 Microns)
Irregular shapes
Possess numerous fenestrea
Basal lamina incomplete or absent
Lack pinocytotic vesicles

Front 29

What are valves?

Back 29

Semilunar flaps consisting of a thin CT core covered by endothelial cells.

Front 30

What are the characteristics of veins?

Back 30

- Carry blood from capillaries to heart.
- Increase in size as they get closer to heart.
- Some contain valves.
- Some large veins have longitudinally-oriented smooth muscle in adventitia.

Front 31

What are the comparisons of veins to arteries?

Back 31

- Walls are thinner and less elastic than arteries, and layers less distinct.
- Lumens larger than arteries.

Front 32

What are the characteristics of Venules (muscular)?

Back 32

0.2-1.0 mm in diameter
0-3 layers smooth muscle

Front 33

What are the characteristics of Postcapillary venules?

Back 33

About 15-20 microns in diameter.
No tunica media.
Site of emigration of white blood cells into CT in inflammation.

Front 34

What do lymphatic capillaries do and what are they similar to?

Back 34

Transport lymphatic fluid from tissues to circulation.
Similar in structure to veins.
Contain valves to prevent backflow of lymph.
More permeable than blood capillaries.
Effective in removing protein-rich fluid from tissues.

Front 35

What do Lymphatic capillaries begin as?

Back 35

“blind-ended” tubes

Front 36

Where are lymphatic capillaries found?

Back 36

Found in all tissues except: CNS, cartilage, bone and bone marrow, thymus, teeth, and placenta.

Front 37

What are only cellular elements in lymph?

Back 37

Lymphocytes

Front 38

What do Lymphatic capillaries lack?

Back 38

A continuous basal lamina.

Front 39

How many heart chambers are there?

Back 39

4
2 atria
2 ventricular

Front 40

What separates right and left sides of the heart?

Back 40

Interatrial and interventricular septums

Front 41

What are Heart valves composed of?

Back 41

Dense irregular CT covered by endothelium

Front 42

What composes the “Fibrous Skeleton” of the heart?

Back 42

Four fibrous rings of dense CT
Fibrous ring of Aorta, pilmonary trunk, mital valve, and tricuspid valve

Front 43

What are the characteristics of the fibrous skeleton of the heart?

Back 43

- Fibrous central region provides for attachment of cardiac muscle and valves.
- Composed of dense CT.
- AV bundle passes through opening.
- Acts as electrical insulator by preventing flow of impulses between atria and ventricles.

Front 44

What are the three layers of the heart and what are they continuous with in blood vessels?

Back 44

Endocardium
Myocardium
Epicardium
--> Tunica intima, tunica media, and tunica adventitia

Front 45

What are the characteristics of the endocardium of the heart?

Back 45

Lined with endothelium.
Underlying subendocardial dense CT.
Middle layer of CT and smooth muscle
Deeper layer of CT: subendocardial layer

Front 46

What is the Impulse conduction system of the heart?

Back 46

- SA node initiates contraction that spreads along cardiac muscle fibers of atria.
- Impulse picked up at AV node and conducted across fibrous skeleton via AV bundle.
- AV bundle form left and right branches and then into Purkinje fibers.
- Cardiac muscle cells have a wave of contraction mediated by gap junctions.

Front 47

What are the characteristics of purkinje fibers?

Back 47

Modified cardiac muscle cells that are specialized to conduct impulses.
Located in subendocardial connective tissue.
Coordinates contractions of atria and ventricles.
Contain many gap junctions.
Contain fewer myofibrils than cardiac muscle cells, and are larger and contain more glycogen (lighter staining).