Circulatory System Flashcards
(117 cards)
1
Q
Endocardium contains:
A
- Endothelium
- Supporting CT
- Some adipose tissue
2
Q
Myocardium contains:
A
- Cardiac myocytes
2. Purkinje fibers
3
Q
Epicardium AKA:
A
Adventitia
4
Q
Pericardium AKA:
A
Outer membrane
5
Q
Purkinje fibers
A
Conduction system of heart
6
Q
Cardiac skeleton
A
Fibrous skeleton of the heart → structure of dense CT which separates atria from ventricles
7
Q
Annulus
A
Cardiac skeleton (CT) surrounding valves
8
Q
Trigone
A
Cardiac skeleton (CT) → triangular area between 2 AV canals and aortic valve
9
Q
2 parts of cardiac skeleton
A
- Annulus
2. Trigone
10
Q
Heart valves are made of?
A
Folds of endocardium
11
Q
Heart valves are supported by?
A
Cardiac skeleton (dense CT)
12
Q
Edges of cusps of valves are anchored by?
A
Chordae tendinae
13
Q
3 layers in blood or lymph vessel
A
- Tunica intima
- Tunica media
- Tunica adventitia
14
Q
Epicardium contains?
A
- Mesothelium → secretes serous fluid
- Supporting CT
- Broad adipost tissue
15
Q
Purkinje fibers derived from?
A
Cardiac muscle
16
Q
Purkinje fiber cells
A
Cells larger than muscle fiber → no T-tubules
17
Q
3 layers of tunica intima
A
- Endothelium (always)
- Subendothelial CT (sometimes)
- Internal elastic lamina (sometimes)
18
Q
Tunica media
A
Smooth m. with varying amounts of elastic lamina
19
Q
External elastic lamina is in what layer?
A
Tunica media
20
Q
Tunica adventitia
A
CT of vessel wall
21
Q
Tunica adventitia CT
A
Dense or loose irregular
22
Q
In larger vessels, the tunia adventitia carries?
A
Blood and nerve supply for that vessel:
- Vasa vasorum
- Nervi vasorum
23
Q
Vasa vasorum
A
Blood supply for vessel
24
Q
Nervi vasorum
A
Nerve supply for vessel
25
Examples of elastic aa.
1. Aorta
2. Pulmonary
3. Carotid
26
Tunica intima is found where?
Innermost layer, just inside endothelium
27
Tunica intima of elastic aa.
Very thin → internal elastic lamina difficult to observe
28
Tunica intima of elastic aa. contains?
1. Fibroblasts
| 2. Myointimal cells
29
Atherosclerosis caused by?
Myointimal cells deposit lipid and thicken with age
30
Tunica media of elastic aa.
Thickest layer → external elastic lamina not readily apparent
31
Tunica media composition in elastic aa.
Concentric layers of elastin with smooth m. cells and reticular fibers between layers
32
Tunica adventitia in elastic aa.
Thin compared to tunica media
33
Muscular aa. found where?
Peripheral aa.
34
Tunica intima of muscular aa. contains?
1. Endothelium
2. CT
3. Internal elastic lamina
35
Tunica intima of muscular aa. appearnce
Difficult to see → only visible in pathological conditions (ex: atherosclerosis)
36
What layer of muscular aa. thickens to increase peripheral blood pressure?
Tunica intima
37
Thickening of tunica intima (high blood pressure) can cause?
1. Hypertension
2. Coronary artery disease
3. Stroke
4. Aneurysm
38
Tunica media in muscular aa.
Thick layer of smooth m., contains fibers and proteoglycans
39
External elastic lamina
Made of elastin fibers → divide tunica media and adventitia
40
Tunica adventitia of muscular aa.
Very thick external CT layer
41
Artery lumen diameter
>0.3 mm
42
Artery must have ___ layers of muscle cells
>3
43
Arteriole elastic lamina
No external, diminishing internal
44
Arteriole must have ___ layers of muscle cells
45
Smallest branch of arterial system
Arterioles
46
Arteriole function
Delivers and regulates floor blood to capillary bed
47
How do arterioles regulate systemic blood pressure?
Arteriole constriction increases resistance to peripheral blood floow
48
NO produced by?
Vascular endothelial cells and macrophages
49
NO function
Vasodilation (very potent)
50
NO is synthesized from?
L-arginine
51
Tunica intima of arterioles
Internal elastic lamina disappearing
52
Tunica media of arterioles
1-3 layers of smooth muscle cells
53
Tunica adventitia of arterioles
Narrow layer of CT
54
Capillaries consist of?
Only endothelium and basement membrane
55
4 types of capillaries?
1. Continuous
2. Fenestrated
3. Discontinuous
4. Sinusoidal
56
Continuous capillaries have?
No pores in endothelial cells
57
Continuous capillaries most commonly found in?
1. Muscle
2. Brain
3. Thymus
4. Bone
5. Lung
58
Fenestrated means?
Windowed
59
Fenestrated capillaries have?
Pores in endothelial cells (+/- diaphragm)
60
Fenestrated capillaries most commonly found in?
Tissues with substantial fluid transport:
1. Intestine
2. Kidney
3. Endocrine
61
Discontinuous capillaries
Gaps between cells
62
Discontinuous capillaries are found in?
Liver and spleen sinusoids
63
Sinusoidal capillaries are?
Special
64
Sinusoidal capillaries are found in?
1. Liver
2. Spleen
3. Bone marrow
4. Lymph nodes
65
Sinuisodal capillary appearance
1. Wide lumen
| 2. Incomplete basal lamina
66
Capillary diameter
Same as RBC (7-9 um)
67
Sinusoid diameter
30-40 um
68
What allows for capillary function?
Very thin endothelial cell layer
69
Capillary function in tissue beds
Allow for exchange of water and solutes between blood and tissue
70
Capillary function in lung
Allow for exchange of water and solutes between blood and environment
71
4 cells in capillaries
1. Pericytes
2. Pericyte derivatives
4. Mast cell
5. Scattered smooth muscle cells
72
What is a pericyte?
Residual mesenchymal / stem cell
73
Example of pericyte derivative in capillaries
Mesangial cells of glomerulus
74
Meangial cell function?
Controls blood flow
75
How is blood flow controlled?
| What tells capillaries to constrict or dilate?
1. ANS
| 2. Circulating hormones
76
Microcirculation is the?
Interaction of arterioles and venules through capillaries at peripheral tissues
77
4 things microcirculation exchanges
1. Gas
2. Nutrient
3. Fluid
4. Metabolic waste
78
Variables in microcirculation
1. Capillary diameter
2. Capillary endothelium
3. Arteriovenous shunts
4. Capillary network abundance
79
Microcirculation blood flow
```
Arteriole →
Capillaries →
Post-capillary venule →
Collecting venule →
Muscular venule
```
80
Venules are?
Similar to capillaries with a larger diameter
81
Tunica intima of venules
Endothelium only
82
Tunica media of venules
Thin layer or not present
83
Tunica adventitia of venules
Present
84
How do you distinguish between venules and small veins?
If it's next to an arteriole, call it a venule
85
Tunica intima of veins
Present
86
Tunica media of veins
Few layers of irregularly arranged smooth muscle (may be discontinuous)
87
Tunica adventitia of veins
Thickest part of wal
88
3 ways to differentiate arteries from veins
1. Veins/venules have thinner wall
2. Arteries and veins or arterioles and venules are found side-by-side
3. Arteries don't have valves; many veins do
89
Vein appearance
1. Thin muscular wall
2. No internal elastic lamina
3. Wide lumen (compared to wall thickness)
4. Packed with RBCs
90
What veins do have internal elastic lamina?
Large veins
91
What is a neurovascular bundle?
Similar sized vessels, nerves and lymphatics travel together
92
What is the lymphatic circulation?
One-way tissue fluid drainage system
93
Lymphatic circulation is associated with?
Venous system
94
Function of valves in the lymphatic circulation system?
Ensure fluid moves toward large veins cranial to heart
95
Pressure of lymphatic circulation
Very low
96
Very low pressure in lymphatic circulation pathology
Easily occluded, obstructed or overwhelmed → edema
97
Lymph capillaries
Blind-ended
98
Lymp capillaries begin in?
Perivascular spaces of tissue beds
99
Lymph vessel function
Transport excess interstitial fluid, proteins, solutes and macromolecules through lymph nodes and back to venous system
100
Lymph vessel safety valves are located between?
Extravascular and intravascular fluid pools
101
Function of lymph vessel filtering system
Impedes MOs and cancer cells
102
Lymphatic capillary contains
Extremely thin endothelium only → no basement membrane
103
How do you find lymphatic capillaries?
Look like a space in the tissue → look for endothelium
104
How do you distinguish between large lymph vessels and veins?
1. Lymph vessels have thinner walls
2. More numerous valves (lymph > veins)
3. No RBCs in lymph vessels
105
Lymph vessels contain?
WBCs (no RBCs) and precipitated protein
106
Circulatory shock is?
Life-threatening acute symptom
107
Circulatory shock occurs when?
Hypovolemia of >35%
108
Hypovolemia can be caused by?
1. Blood loss
| 2. Extreme vasodilation by endotoxin
109
How does hypovolemia lead to circulatory shock?
Widespread inadequacy of tissue perfusion
110
Widspread inadequacy of tissue perfusion leads to?
| On a cellular level, don't say hypovolemia or circulatory shock
1. Cellular hypoxia
2. Cellular injury / organ damage
3. Lactic acidosis
111
How does hypovolemia cause lactic acidosis?
Lactic acid is released from damaged cells
112
What is peripheral vasoconstriction?
Compensation for circulatory shock
113
Peripheral vasoconstriction function
Preserve blood flow to vital organs
114
How does peripheral vasoconstriction preserve blood flow to vital organs?
Decreases capillary hydrostatic pressure
115
How does peripheral vasoconstriction decrease capillary hydrostatic pressure?
Facilitates flow of interstitial fluid into circulation
116
Arteries can be either?
Elastic or muscular
117
Main difference between elastic and muscular aa.
Tunica media in elastic arteries contains concentric sheets of elastin
