vascular system histology - cole Flashcards
1
Q
hemangioma
A
abnormally dense collection of capillary vessels
- common tumors of infancy (10%)
- focal or diffuse, more secondary complications
2
Q
naevus flammeus
A
port wine stain
superficial and deep dilated capillaries in the skin
3
Q
progressive tumor growth is dependent on
A
angiogenesis
4
Q
heart
A
folded endothelial tube
wall thickened to act as a regulated pump
5
Q
3 layers of cardiac wall
A
endocardium
myocardium
epicardium
6
Q
endocardium
A
- endothelial lining
- subendothelial connective tissue
7
Q
myocardium
A
functional syncytium of striated cardiac muscle fibers forming 3 major types of cardiac muscle:
artial
ventricular
specialized excitatory/ conductive muscle fibers
8
Q
epicardium
A
- visceral layer of pericardium
- low-friction surface lined by mesothelium in contact with parietal pericardial space
9
Q
cardiomyoctes (3)
A
contractile - to move blood
myoendocrine - produce ATRIAL NATRIURETIC FACTOR: stimulates diuresis, excretion of Na+ in urine via increasing GFR, reduces blood volume!
nodal - SA node and AV node - regulate contraction of heart
10
Q
arteries organized in 3 major tunics/ layers
A
tunica intima
tunica media
tunica externa/ adventitia
11
Q
tunica externa/ adventitia
A
- outermost layer of blood vessel wall
- loose CT that contains elastic and collagen fibers
- anchors vessel to other tissues
- EXTERNAL ELASTIC LAMINA seen separating tunica media from adventitia
- vasa vasorum
12
Q
tunica media
A
- middle layer of vessel wall
- circularly arranged layers of smooth muscle cells (M = media, M = muscle)
- vasoconstriction/ vasodilation
13
Q
tunica intima/ interna
A
- innermost layer of bood vessel wall
- endothelium and subendothelial layer
- INTERNAL ELASTIC LAMINA, external layer of elastic fibers
14
Q
3 major groups of arteries
A
large elastic arteries
medium-sized muscular arteries
small arteries and arterioles
15
Q
large elastic arteries that can’t maintain their shape/ weaken result in
A
aneurysm
16
Q
large elastic (conducting) arteries
- characteristics
- systole/ diastole
- tunica intima, media, adventitia
A
- receive blood from heart under high pressure
- keep blood circulating CONTINUOUSLY (heart pumps INTERMITTENTLY)
- distend during systole, recoil during diastole
- tunica intima: endothelium and subendothelial CT
- tunica media: lots of fenestrated elastic sheaths, bundles of smooth muscles permeate the narrow gaps between elastic lamellae
- TA - vasa vasorum, nervi vasorum, lymphatics recognizable
17
Q
examples of large elastic (conducting) arteries
A
aorta and its largest branches:
- brachiocephalic
- common carotid
- subclavian
- common iliac arteries
18
Q
muscular/ distributing arteries
- characteristics
- diameter
- tunica intima, media, adventitia
A
- allow selective distribution of blood to different organs in response to functional needs
diameter: 3 mm or >
tunica intima - 3 layers: endothelium, subendothelium, internal elastic lamina (IEL)
tunica media: sig. reduction in elastic components, increase in smooth muscle fibers
tunica media/ adventitia junction: fenestrated external elastic lamina visible in larger vessels of this group
19
Q
medium sized arteries examples
A
axillary radial tibial popliteal splenic mesenteric intercostal arteries
20
Q
regarded as resistance vessels and major determinants of systemic BP
A
arterioles
21
Q
arterioles/ resistance vessels
- characteristics
- function
- structural adaptations
A
- final branches of arterial system
- regulate distribution of blood to different capillary beds via vasoconstriction/ vasodilation
- structural adaptation: walls with circularly arranged smooth muscle
- partial contraction (tone) of vascular smooth muscle exists in arterioles
22
Q
the site of microcirculation, microvascular bed, composed of
A
- terminal arteriole (metarteriole)
- capillary bed
- postcapillary venules
23
Q
capillary bed consists of
A
- preferential/ thoroughfare channels (slightly larger capillaries) with CONTINUOUS blood flow
- true capillaries (small capillaries) with INTERMITTENT blood flow
24
Q
functional units of the CV system
A
capillaries (smallest blood vessels)
- connect arterioels to venules
25
capillary and capillary bed characteristics, layers
diameter: 5 - 10 um, large enough to accomodate one RBC, thin enough (0.5 um) for gas diffusion
only has tunica intima! with basement membrane and endothelium only
- capillary bed (10-100 capillaries) functioning together
26
the 3 basic kinds of capillaries
continuous - lined by endothelium w/ tight junctions and a basal lamina w/ pericytes
fenestrated - pores or fenestrae (GI and kidney) allowng things to leak out based on charge/ size
sinusoids/ discontinuous capillaries - incomplete endothelial lining and basal lamina w/ gaps or holes between and within endothelial cells (liver and spleen)
27
preferred site of migration of blood cells into tissues (diapedesis)
postcapillary venules
28
postcapillary venules.. merge to.. which merge to..
postcapillary venules ==> muscular venules ==> series of veins of progressively larger diameter
29
vein wall characteristics vs. arteries
- relatively thin wall
| - compliance vessels, distensible wall ==> high capacitance ==> higher content of blood vs. arteries
30
if blood not flowing through valve but pooling underneath, get
thrombi!
| Deep venous thrombosis
31
vein layers
- tunics but TM/ TA not distinct
- distinct IEL not seen
- muscular TM thinner than arteries; smooth muscle cells with irregular orientation, approximately circular
32
hemorrhoids are..
dilations of internal or external rectal venous plexuses
33
get varicose veins when..
valves in our veins don't close properly
34
vasculitis
| def., DM
inflammation of blood vessels
- blood vessel walls thicken, weaken, narrow/ scar ===> restricts blood flow ==> organ/ tissue damage
- can have vasculitis specific to different kind of arteries.
35
lymphatic vessels fx
- conduct immune cells and lymph to lymph nodes
- remove excess fluid accumulated in interstitial spaces
- transport chylomicrons (lipid-containing particles) through lacteal lymphatic vessels inside intestinal villi
36
lymphatic capillaries
beginning
- wall
- location
```
begin as dilated tubes with closed ends in proximity to blood capillaries and collect tissue fluid (lymph)
- an endothelium lacking a complete basal lamina
- found in most tissues except:
cartilage
bone
epithelia
CNS
placenta
```
37
lymphatic drainage - intrinsic contraction
- vessels become expanded by lymph, smooth muscle of wall contracts
- segment of lymphatic vessel between successive valves (lymphangions) behaves like an automatic pump
38
lymphatic drainage - extrinsic contraction
external factors compressing lymph vessel and causing pumping
- contraction of surrounding muscles during exercise
- arterial pulsations
- compression of tissues by forces outside the body
39
result of impaired lymph drainage
edema!
| excess fluid accumulating in tissue spaces
40
cause of lymphadema
defec tin transport of lymph because of abnormal vessel development/ damaged lymphatic vessels
41
parasitic infection of lymphatic vesels by wuchereria bancrofti or brugia malayi worms, transmitted by mosquito bites;
disease name, occurance, effects
filariasis (elphantiasis)
- causes damage to lymphatic vessels with chronic lymphedema of legs and genitals
- occurs in tropical countries
42
cause of chylous ascites/ chylothorax
accumulation of high fat containing fluid, or chyle, in abdomen or thorax as a result of trauma, obstruction, or abnormal development of lymphatic vessels
43
vasoactive substances released by endothelial cells, causing relaxation of smooth muscle
- what else can thye do?
```
nitric oxide (NO) and prostacyclin!
- prostacyclin also prevents platelet adhesion and clumping leading to blood clotting
```
44
very potent vasoconstrictor peptide
endothlein 1`
45
capillary endothelial cells are most permeable at? what does this location have the greatest permeability to?
at venous end
| - most permeable to leukocytes!
46
atherosclerosis results in
myocardial infarction
stroke
ischemic gangrene
47
atheroscleorsis is..
which vessels does it effect?
genetics?
correlated with?
- a chronic inflammatory disease (features of inflammation at all stages of development)
- thickening and hardening of walls of arteries (often ones sustaining high BP) caused by atherosclerotic plaques of lipids, cells and CT deposited in tunica intima
- does NOT affect veins
- correlated with serum levels of cholesterol/ LDL
- familial hypercholesterolemia - genetic defect in lipoprotein metabolism -atherosclerosis and MI before patients reach 20 years of age
