Circulatory System Flashcards
1
Q
Objectives
A
- Heart
- Identify the heart layers
- Review the Purkinje fibers in the hert
- Blood and lymph vessels
- Descibe the layer of a typical blood or lymph vessl
- Descibe and recognize the differences bewteen elastic arteries, muscular arteries, arterioles, capillaries, veins, and lymph vesselts
- Identify the vasa vasorum and nervi vasorum (blood vessels and verve vessels in the tunica adventitia or large vessels)
- Recognize and descibe arteries, arterioles, capillaries, veins and lymph vessels
- Define:
- Endothelium, tunica intima, tunica media, tunica adventitia, inernal elastic lamina, basement membrane, sinusoid, pericyte, fenestrated, interstitial, endocardium, myocardium, epicardium, visceral pericrdium, vasoconstriction, hypovolemia, edema
2
Q
Heart Layers
A
-
Endocardium:
- Has endothelium
- small amount of supporting connective tissue (delicate collagenous layer and deeper fibroelastic layer
- Adipose tissue deposits in places
- Simple squamous epithelium
-
Myocardium:
- Contains cardiac myocytes and purkinje fibers
- Muscle layer, with vessels
-
Epicardium: (Visceral pericardium)
- Contains mesothelium that secretes serous fluid
- some supporting connective tissue similar to that of endocardium
- broad layer of adipose tissue
- Essentially the same as endocardium, but with thick layer of fat
3
Q
Purkinje fibers
A
- Part of the myocardium
- modified cardiac myocytes
4
Q
Cardiac skeleton
A
- Serves as an anchor for the valves at level of the valves of the heart
- Annulus - surround valves
- Trigone - Triangular area between the 2 AV canals
- Septum - between the ventricles
5
Q
Heart Valves
A
- Folds of endocardium
- supported by the cardiac skeleton
- Edges of cusps of valves are anchored by the chordae tendinae
6
Q
Blood and Lymph systems General Introduction
A
- Blood and Lymph vascular systems are similar in some respects, and different in others
- Blood passes through a circuit
- Lymph is a one-way drainage from the tissues back to the vascular system
- They are often found together with nerves
- Blood vessels have a stronger wall with more components of the layers than lymph vessels
- In small lymph vessels only the endothelium is visible
7
Q
Vessels General Introduction
A
- An Arteriole is a small artery; a venule is a small vein
- Arterioles -have an objective way to idetify them, based on the number of smooth muscle cell layers
- Venules - Not so much, but they accompany arterioles (veins accompany arteries)
- When comparing arteries and veins:
- Arteries/arterioles have a uniform thickness of the wall
- Veins/venules have a very thin wall relative to the size of the vessel, and it may not be uniformly thick
- Arteries do NOT have valves
- Exception is Aorta
- Veins and lymph vessels usually have valves
- Valves in the simplest form are double- layered folds of endothelium
8
Q
Layers of Vessels Walls
A
-
Tunica Intima - Epithelium and some connective tissue, and an elastic layers
- Endothelium
- Connective tissue
- Internal elastic lamina
-
Tunica Media - smooth muscle cells and variable amounts of fibers (mainly elastin)
- Elastic arteries have smooth muscle with large sheets of elastin
- Layers of smooth muscle with elastic fibers
- Elastic fibers are very prominent in elastic arteries
- External elastic lamina, but not always obvious
-
Tunica Adventitia - Connective tissue covering of the vessel
- May contain vessels and nerves if the blood vessel is very large
- Elastic arteries have a more collagenous outer covering, while muscular artreies have a more elastic outer covering
- Outer layer of connective tissue
- Mixed collagen and elastic fibers
- More collagen in the elastic arteries
- More elastin in the musculr arteries
- May contain vascular and nerve plexus
9
Q
Tunica Intima
A
- 3 layers
- Endothelium
- Connective tissue
- Internal elastic lamina
10
Q
Tunica Media
A
- smooth muscle cells and variable amounts of fibers (mainly elastin)
- Elastic arteries have smooth muscle with large sheets of elastin
- Layers of smooth muscle with elastic fibers
- Elastic fibers are very prominent in elastic arteries
- External elastic lamina, but not always obvious
11
Q
Tunica Adventitia
A
- Connective tissue covering of the vessel
- May contain vessels and nerves if the blood vessel is very large
- Elastic arteries have a more collagenous outer covering, while muscular artreies have a more elastic outer covering
- Outer layer of connective tissue
- Mixed collagen and elastic fibers
- More collagen in the elastic arteries
- More elastin in the musculr arteries
- May contain vascular and nerve plexus
12
Q
Elastic Arteries
A
- Tunica Intima contains all 3 layers
- Tunica Media is the thickest layer
- Many concentric layers of elastin, with smooth muscle cels between the layers
- External elastic lamina is not readily apparent because of the thick elastic laminae
- Tunica Adventitia is thin comparitively
13
Q
Muscular Arteries
A
- Tunica Intima - contains endothelium, connctive tissue, and internal elastic lamina
- Connective tissue hard to see with light microscope unless thickened by atherosclerosis
- Tunica Media - thick layer of smooth muscle
- contains fibers and proteoglycans (smooth muscle and fibrocytes are developmental “cousins”)
- External elastic lamina is part of tunica media
- Tunica Adventitia - external connective tissue layer, can be very thick
14
Q
Tunica Intima - Muscular Artery
A
- Inner lining; can have 3 sublayers;
- Endothelium (always)
- Subendothelial connective tissue (not visibe in small vessels)
- Internal elastic lamina
15
Q
EM slide of small muscular artery
A
- Muscular (or distibuting) artery is a medium-sized artery composed principally of a tunica intima and circularly arranged smooth muscle
-
Tunica Intima:
- Endothelium (green) - single layer of flattened endothelial cells
- Inner Elastic Lamania (tan) - layer of elastic fibers
-
Tunica Media (light blue) - thick layer of smooth muscle along with collagen fibers and a few elastic fibers
- Caveolae - large number of small invaginations of the plasma membrane of the smooth muscle cells
- Tunica Adventitia - only a few collagenfibers of this layer are visible in this micrograph
- Part of a red blood cell (dark red) can be seen in the lumen of the artery
16
Q
Tunica Media - Muscular Artery
A
- Smooth muscle with varying amounts of elastic laminae
- The external elastic lamina is part of this layer but may be difficultto see
17
Q
Tunica Adventitia - Muscular Artery
A
- The external connective tissue of the vessel wall
- Dense or loose irregular connective tissue
- More elastin in the tunica adventitia of a muscular artery, especially right next to the muscle layer
23
Q
Fenestrated Capillaries
A
- Have pores within endothelial cells
- diaphragm covers the pore
- Found in tissues involved in absorption and fluid transport (small intestine and kidneys) and some endocrine glands
- Picture:
- Capillary (green) - inner (lumenal) surface of the endothelial cells
- Fenestrations (approx. 50 - 100 nm) - endothelial cells contain numerous pores lacking diaphragms
- Fenestrations allow access of blood to the underlying basement membrane
- Podocyes (yellos) - remnants surrounded the capillary
- Capillary (green) - inner (lumenal) surface of the endothelial cells
24
Q
Sinusoidal Capillaries
A
- Special capillaries found in the liver, spleen and bone marrow
- Have a wide lumen with a discontinuous endothelium (gaps between endthelial cells)
27
Q
Veins and venules
A
- Distiction between venules and small veins is somewhat artificial
- If next to an artery its a vein
- if next to an arteriole its a venule
- Both can have valves
