Vascular bio III Flashcards
What are the two factors that lead to increased vascular stress?
Increased pressure
Increased flow
What drives transformational changes in blood vessels?
Changes in stress on the walls
High flow leads to what two major changes in a vessel?
Increase in outside diameter
Increase in luminal diameter
Low flow leads to what two major changes in a vessel?
Decrease in outside diameter
Decrease in luminal diameter
Increased pressure in large arteries leads to what change?
Outward hypertrophy (vessel becomes larger in diameter as wall becomes thicker and diameter of lumen remains unchanged)
Increased pressure in small arteries leads to what change?
Inward hypertrophy (outside diameter remains unchanged as wall becomes thicker and the diameter of lumen decreases)
Is there a change in wall thickness in arteries in response to increased flow?
No
What are the three responses arterioles have in response to increased pressure?
- Inward hypertrophy
- Inward remodeling (eutrophic)
- Rarefaction (disappear)
What are the three layers of the heart, and what do they correspond to compared to arteries?
- Endocardium (tunica intima)
- Myocardium (tunica media)
- Epicardium (tunica adventitia)
What type of epithelial cell layer comprises the endocardium?
simple squamous
What does the myoelastic layer of the heart endocarium comprised of?
Smooth muscle, as well as elastic and collagen fibers.
What are the three muscle cell types foind in the myocardium?
Contractile
Myoendocrine
Specialized conductive
What are the four layers of the endocardium?
- Endothelium +basal lamina
- Subendothelial layer
- myoelastic layer
- Subendocarium
What are the contents of the subendothelial layers of the endocardium?
- Loose CT
- Small blood vessels
- Nerve fibers
- Purkinje fibers
What layer of the heart are Purkinje fibers found?
The subendocaridum
Are purkinje fibers found in atria?
Negative
Which layer is the thickest when looking at a cross section of a ventricle?
Endocardium
What are the two types of granules that are found in myoendocrine cells in the myocardium? What do these function as?
Atrial natriuretic factor
B-type natriuretic factor
Both are diuretics
What type of CT is found in the epicardium of the sulci of the heart? What does this sit between?
Adipose
Separates the myocardium and the epicardium
What is the outer layer of the epicarium? What type of epithelium comprises this area?
Mesothelium
Simple squamous + BL
What is the most discernible component of the epicardium of the heart outside the sulci?
Fibro-collagenous component
What is the function of the cardiac skeleton?
Anchoring the cardiac muscle and valves
Electrical insulation
What is the cardiac skeleton made of?
Dense CT (collagen etc, NOT bone)
What are the three components of the AV valves?
Atrialis
Spongiosa
Fibrosa
What is the function of the atrialis?
Elastic and collagenous tissue structure subjacent to endothelium that helps to contract the valve
What is the spongiosa?
Middle layer of loose CT that serves as a shock absorber in the cardiac endothelium
Rich in proteoglycans
What is the fibrosa part of the cardiac endothelium?
core of denser irregular collagenous tissue for mechanical integrity. Is subjacent to endothelium of ventricular surface
Of the three layers of the atria (atrialis, spogiosa, and fibrosa), which layer faces the atrium? The ventricle?
Atrium = atrialis Ventricle = fibrosa
What is myxomatous?
degeneration of AV valve (floppy valve)
Possibly due to overexpression of dermatin sulfate
What are the three layers of the ventricles?
- Fibrosa
- Spongiosa
- Ventricularis
What is the fibrosa of the semilunar valves (composition/function)?
Core of irregular collagenous tissue for mechanical integrity
It is subadjacent to endothelium
What is the spongiosa of the semilunar valves?
Middle layer
What is the ventricularis of the semilunar valves (composition/function)?
layer of elastic and collagen tissue subjacent to endothelium of ventricular surface
Where is the fibrosa of semilunar valves situated relative to the aorta/ventricle? Ventricularis?
Fibrosa = aortic side Ventricularis = ventricular side
What is the difference between the fibrosa of the semilunar valves, compared to the AV valves?
Much thicker fibrosa d/t increased pressure in the ventricles
The conduction system of the heart is composed of what type of cells (generally)?
Modified muscle cells
What are the three major structures that comprise the conduction tissue of the heart?
- SA node
- AV node
- Atrioventricular bundle (bundle of His)
Which is larger, the RBB or the LBB?
LBB
Why does teh SA node stain lighter than normal cardiac muscle cells?
Fewer myofibrils
Cells are smaller
The bundle of his is connected to msucle cells by what?
Gap junctions
What are the five major histological characterisitcs of Purkinje cells?
- Clear cytoplasm
- few myofibrils
- Abundant glycogen
- 1-2 nuclei per cell
- 2x diamter of cardiac muscle cells
Are Purkinje fiber cells acidophilic or basophilic?
Acidophilic d/t few myofibrils
What is the physiological significance of Purkinje cells being larger than cardiac myocytes?
Better/faster transmission of electrical signals
What is the physiological significance of gap junctions in cardiac muscle cells?
Fast transmission of electrical signals
Where do cardiac stem cells exist?
AV sulcus
What is the function of cardiac stem cells?
Migrate from the AV sulcus to sites of injury
What do cardiac stem cells (CSCs) and early committed cells (ECCs) differentiate into?
SMCs and endothelial cells
Are heart cells replaced throughout our lifetime?
Yes, 11-15 times via cardiac stem cells
True or false: lymph capillaries are blind ended?
True
Are there pericytes or smooth muscles cells around lymphatic capillaries?
Negative
What are lymphatic vessels lined by?
incomplete BL + single layer of endothelial cells
What anchors lymph capillaries to prevent them from collapsing on themselves?
Microfibrils
True or false: lymph capillaries transport RBCs and leukocytes
False–no RBCs, just leukocytes
What is the physiological significance of the openings found in lymph capillaries?
Easy movement of lymph from the ECM
Why is there no basal lamina in lymph capillaries?
It would hider lymph flow
Are lymphatic vessels’ walls thinner, thicker, or about the same as veins?
Thinner
Are there valves in lymphatic vessels?
Yes
Is there smooth muscle surrouding lymphatic ducts?
Yes
How can one differentiate veins from lymphatic vessels when looking at a slide that has both?
Lymph will not have RBCs, veins will
What happens histologically as you move from small to medium/larger lymph capillaries?
Smooth muscle becomes present in the tunica media
What is LYVE-1 and why do you care?
A specific lymphatic endothelial marker that can be overexpressed in CA
Rheumatic fever is caused by what bacteria?
Streptococcal pharyngitis
What is the immune response in rheumatic fever?
mitral valve vegetations and Aschoff body formation (focus of lymphocytes, plasma cells and macrophages).
These morphologic changes are due to antibodies cross-reacting with self-antigens in the heart and T cell-mediated reactions.
