Exam2 - Circulatory System Flashcards
1
Q
contents of circulatory system
A
heart, blood vessels, lymphatic system
2
Q
blood vessel layers
A
tunica intima, tunica media, tunica adventitia
3
Q
vasa vasorum
A
smaller vessels branching off large vessels through adventitia and outer part of media
4
Q
which vessels have more vasa vasorum?
A
veins
5
Q
nervi vascularis
A
lymphatics and nerves in adventitia of large vessels
6
Q
tunica intima composition
A
endothelium + underlying subendothelial CT - including internal elastic lamina in larger vessels
7
Q
tunica media composition
A
mostly smooth muscle cells and external elastic lamina when present
8
Q
tunica adventitia composition
A
fibroelastic CT
9
Q
fibroelastic CT
A
dense irregular CT w/ small amounts of elastic fibers
10
Q
artery classifications
A
large = elastic; medium = muscular; small = arterioles
11
Q
elastic arteries
A
conducting arteries that conduct blood to muscular arteries
12
Q
examples of elastic arteries
A
aorta, pulmonary, brachiocephalic, common carotid, subclavian, common iliac arteries
13
Q
elastic artery internal elastic lamina
A
present but incomplete
14
Q
elastic artery subendothelial layer composition
A
loose CT w/ collagen, elastic fibers, fibroblasts
15
Q
elastic artery media
A
thick w/ 40-70 concentric elastic sheets
16
Q
elastic artery adventitia
A
thin w/ elastic and collagen fibers
17
Q
elastic artery external elastic lamina
A
no distinct layer
18
Q
muscular arteries
A
distributing arteries that deliver blood to organs
19
Q
size of muscular arteries
A
0.5 mm - 1 cm
20
Q
innervation of muscular arteries
A
postganglionic sympathetic nerves
21
Q
muscular artery intima
A
thinner than in elastic arteries
22
Q
muscular artery internal elastic lamina
A
yes -well developed
23
Q
muscular artery subendothelial CT
A
lacks smooth muscle cells
24
Q
muscular artery media
A
up to 40 circular layers of smooth muscle interspersed w/ elastic fibers
25
muscular artery external elastic lamina
yes - thick
26
muscular artery adventitia
may be as thick as the media, contains collagen and elastic fibers
27
size of arterioles
diameter less than 0.5 mm
28
arteriole subendothelial CT
very sparse
29
arteriole internal elastic lamina
may or may not be present - consists of a network of fibers not always seen w/ LM
30
arteriole media
1-3 layers of smooth muscle cells w/ occasional elastic fibers
31
arteriole adventitia
layer of loose CT w/ longitudinally arranged collagenous and elastic fibers
32
size of capillaries
7-10 um diameter
33
capillaries
consist of a single layer of endothelial cells surrounded by thin sheath of reticular and collagenous fibers and some pericytes
34
three types of capillaries
continuous, fenestrated, discontinuous
35
pericytes
mesenchymal-like stem cells that differentiate into fibroblasts or smooth muscle cells during wound healing
36
location of pericytes
primarily on post-capillary side of circulation
37
continuous capillaries
somatic capillaries that have continuous endothelium and basal lamina
38
vesicles in continuous capillaries?
numerous pinocytotic vesicles for transcytosis
39
location of continuous capillaries
muscle, CT, CNS, exocrine pancreas, gonads
40
continuous capillaries in CNS have what type of junctions and why?
tight junctions - contribute to BBB
41
fenestrated capillaries
visceral capillaries that have attenuated endothelium w/ large 60-80 nm fenestrae closed by thin 4-6 nm diaphragms but a continuous basal lamina
42
location of fenestrated capillaries
mucosa of GI tract, endocrine glands, renal, kidney (glomerular and peritubular capillaries), choroid plexus, ciliary body
43
special feature of fenestrated endothelium in glomerular capillaries
no diaphragms
44
discontinuous capillaries
sinusoidal capillaries that have irregular, tortuous walls and wide gaps b/w cells with an incomplete basal lamina
45
location of discontinuous capillaries
liver and hemopoietic organs (bone marrow, spleen)
46
veins function
return blood to heart
47
size of venules
12 um - 1 mm diameter
48
venule intima
endothelial cells
49
venule media
1-2 layers of smooth muscle cells
50
venule adventitia
several layers of collagen fibers
51
postcapillary venules
receive blood from capillaries
52
what cells line postcapillary venules?
incomplete layer of pericytes that becomes more complete as vessel enlarges
53
what are postcapillary venules an important site for?
activity in inflammation
54
vasoactive compounds
histamine and serotonin - affect fluid extravasation and migration of WBCs 12-50 um
55
muscular venules
have 1-2 layers of smooth muscle, thin adventitia, and NO pericytes
56
size of small to medium veins
1-9 mm diameter
57
S to M veins subendothelial CT
may have a thin layer
58
S to M veins media
thin w/ some reticular and elastic fibers interspersed w/ smooth muscle cells
59
S to M veins adventitia
well-developed w/ multiple layers of collagenous fibers w/ a few smooth muscle cells and elastic fibers
60
large vein examples
SVC, IVC, portal trunk
61
large vein intima
similar to small veins
62
large vein media
thin
63
large vein adventitia
thick w/ collagenous fibers adn longitunal arranged smooth muscle cells
64
venous valves
paired, semilunar folds of intima covered w/ endothelium that prevent retrograde blood flow
65
location of venous valves
in small or medium sized veins primarily in lower limbs
66
arteriovenous anastamoses
connections primarily b/w arterioles and venules w/ a specialized tunica media that contains a sphincter to control where blood flows
67
when shunt is closed..
arterial blood flows into capillary bed
68
when shunt is open..
blood bypasses capillary bed and flows directly into a vein
69
pre-capillary sphincter
present in some arteriovenous anastamoses - controls amount of blood flowing into the capillary
70
lymph
plasma proteins, fluid, enzymes, lipids, antibodies, hormones, and other macromolecules that leaked from blood vessels and bathe tissues and interstitial spaces
71
flow of lymph
one direction only - toward base of neck
72
lymphatic vessels
endothelium lined vessels that scavenge fluid filtered by lymph nodes and recycles it back into venous circulation at base of neck
73
lymphatic basal lamina
not present
74
origination of lymphatic vessels
in CT as closed-end anastamosing capillaries
75
size of lymphatic vessels
10-50 um diameter
76
where are lymphatic vessels not present?
CNS and bone marrow
77
can lymphatic vessels prevent backflow?
yes - have paired cusp valves
78
where are lymphatics located in skeletal muscle?
perimysium only
79
lacteals
important route of fat absorption in the intestine
80
how do smaller lymphatic vessels remain open?
have fine anchoring filaments attached to perivascular collagen to hold vessel open
81
large lymphatic vessel layers
have intima, media, adventitia, but may be difficult to discern w/ LM
82
how are thoracic duct and right lymphatic duct structurally similar to veins?
are contractile (have smooth muscle) and may be up to 5 mm in diameter
83
what vessel is the main regulator for BP systemically?
arterioles
84
capillary function
exchange of O2, CO2, waste products
85
atherosclerosis
foam cell (lipid laden macrophage) formation and fatty deposits in intima that may block vessel
86
restenosis
smooth muscle cell proliferation that follow angioplasty procedures and may occlude vessel
87
aneurysm
ballooning out of artery due to weakness in arterial wall
88
what causes aneurysm?
atherosclerosis, syphilis, CT disorders like Ehlers-danlos and marfans
89
varicose veins
tortuous, dilated veins primarily in legs of old folks due to decrease in muscle tone and failure of venous valves
90
fxn of prostacyclin produced by endothelial cells?
inhibit platelet adhesion and clot formation
91
origin of prostacyclin
arachidonic acid
92
fxn of NO secretion by endothelial cells?
vasodilation in media (smooth muscle relaxation)
93
fxn of endothelin-1 secretion by endothelial cells?
vasoconstrictor
94
how do endothelial cells regulate traffic of inflammatory cells?
macrophages in surrounding CT secrete cytokines that induce expression of E-selection on endothelial cells -> E-selectin binds to neutrophils, causing them to extravasate by migration through endothelium
95
maternal-fetal circulation
mother's circulatory system not continuous w/ that of fetus - only materials in the blood (no blood) are exchanged b/w mom and fetus where umbilical cord fuses w/ uterine walls (placenta)
96
what does fetal side of circulation consist of?
outer layer of multinucleate syncytiotrophoblast cells
97
endocardium
inner layer of heart homologous to intima that is lined by endothelium and continuous w/ blood vessels that enter/leave heart
98
endocardial subendothelial layer
find collagenous fibers
99
does endocardium contain fibroelastic CT?
yes - thin layer of dense fibroelastic CT
100
endocardial subendocardial layer
loose CT connected to myocardium containing blood vessels, nerves, purkinje fibers
101
myocardium
middle layer of heart homologous to media that contains cardiac muscle tissue
102
myocardium arrangement in ventricles
superficial layers w/ spiral course and deep layers w/ circular course
103
epicardium
outer layer of heart homologous to adventitia (lipid) formed by mesothelial cells
104
epicardial subepicardial layer
loose CT and adipose tissue containing the coronary vessels and nerves
105
fibrous skeleton
dense irregular CT that results in electrical discontinuity b/w myocardial cells of atria and ventricles and therefore controls communication b/w them via AV bundle (insulation)
106
components of fibrous skeleton
septum membranaceum, annuli fibrosi, trigona fibrosa
107
septum membranaceum
fibrous portion of IV septum
108
annuli fibrosi
fibrous rings around the origins of the pulmonary artery, aorta and AV canals
109
trigona fibrosa
fibrous tissue b/w the arterial foramina and the AV canals
110
how are AV valves connected to papillary muscles of ventricles?
fibrous cords called chordae tendineae
111
AV and semilunar valve composition
have both dense and loose CT layers surrounded by endothelium
112
SA node
pacemaker of heart that contains modified cardiac muscle cells concentrically arranged around a nodal artery
113
AV node
node containing cells similar to those in SA node that continues to form a common stem - AV bundle of His
114
AV node location
beneath endocardium of the septal wall of RA
115
AV bundle of His
formed by purkinje fibers that penetrate skeleton and then branch to form left and right bundle branches
116
purkinje fibers
cardiac conduction fibers derived from modified muscle cells that travel in subendocardial layer to heart apex, then reverse direction and branch to make contact and form gap junctions w/ cardiac muscle cells
117
what are purkinje fibers filled with?
glycogen
118
parasympathetic nerves route and effect on heart
from vagus to SA node - slow heart
119
sympathetic nerves effect on heart
accelerate heart beat
120
what do cardiac endocrine cells secrete?
polypeptide hormones
121
location of cardiac endocrine cells
IV septum and atrial cardiac muscle
122
what is atrial natriuretic peptide released in response to?
high BP
123
effect of ANP
increases sodium and water secretion from kidney
124
ANP gene makes what four hormones?
- long acting natriuretic (sodium) peptide
- vessel dilator
- kaliuretic (potassium) peptide
- ANP
