Lecture #28: Cardiovascular Histology Flashcards
What are the components of the endocardium?
Endothelium and Subendothelial Connective Tissue
True or False:
The endocardium is not continuous with the tunica intima of the blood vessels entering and leaving the heart.
False - IS continuous with the tunica intima of the blood vessels entering and leaving the heart.
What layer is located between the endocardium and the myocardium?
Subendocardium Layer
What is contained within the subendocardium layer?
Nerves
Purkinje Fibers
**these are referred to as subendocardial fibers
What do Purkinje Fibers function to do? Also, what type of cells are they?
Carry impulses to ordinary cardiomyocytes.
Large, modified, and specialized cardiac muscle cell.
What makes up the myocardium?
Consists of cardiac muscle cells.
What type of tissue lines the external surface of the epicardium?
The external surface of the epicardium is covered by simple squamous epithelium (mesothelium).
What composes the fibroelastic connective tissue that is covered by the mesothelium?
Fibroelastic connective tissue containing adipose cells, nerves, and coronary vessels.
What are the three cardiac tunics starting from the deepest layer?
Endocardium
Myocardium
Epicardium
What type of fibers originate and insert into the cardiac skeleton?
Myocardial fibers originate and insert into the cardiac skeleton.
What kind of tissue is the cardiac skeleton composed of?
Dense Collagenous Connective Tissue
True or False:
Walls of all blood vessels except capillaries are characterized by three layers (tunics).
TRUE
What are the components of the tunica intima?
> Endothelium and its basal lamina
> Subendothelial Connective Tissue
> Internal Elastic Membrane
Is the endothelium and its basal lamina of the tunica intima found in all arteries and arterioles?
YES
What factor does endothelial cells produce that are crucial in hemostasis?
Endothelial cells produce von Willebrands’s factor VIII.
True or False:
Subendothelial CT of the tunica intima is found in all elastic and muscular arteries and some arterioles.
True
Which type of arteries, elastic or muscular, has an incomplete internal elastic membrane?
Internal elastic membrane -> incomplete in elastic arteries but thick and complete in muscular arteries.
What is the tunica media made up of?
Circular smooth muscle tissue
Fibroblasts
Does the tunica media contain collagen and elastic fibers?
YES
What tunica layer does arterioles not have?
Tunica adventitia
In what tunica layer is vasa vasorum and nervi vasorum found?
Tunica adventitia
What type of tissues does the tunica adventitia consists of and contain?
Consists of Loose Areolar Tissue
Contains Irregular Fibroelastic Tissue with Adipocytes
Got to slide 13
sweet
What does the endocardium, which is the innermost cardiac tunic (layer), line?
Endocardium -> innermost layer, lining the atria and the ventricles.
Are muscular arteries typically distributing or conducting arteries?
Distributing Arteries
Are elastic arteries typically distributing or conducting arteries?
Conducting Arteries
True or False:
Elastic arteries stretch during systole and recoil during diastole.
True
Give 3 examples of elastic arteries that are found in the body?
Aorta
Pulmonary Trunk
Large Branches of Aorta
What is the relationship between smooth muscle layer thickness and the diameter of the vessel?
Thickness of smooth muscle layer decreases as diameter becomes smaller.
Fill in the Blank:
Tunica media consists of smooth muscle that responds to _______ stimulation and hormones.
autonomic
How many layers of smooth muscle cells are typically found in the tunica media of arterioles?
1-3 layers of smooth muscle cells.
True or False:
Arterioles give rise to metarterioles which have a discontinuous layer of smooth muscle tissue.
True
True or False:
Pericytes are differentiated mesenchymal cells.
False - pericytes are undifferenetiated mesenchymal cells.
True or False:
Pericytes may be contractile and can serve as stem cells to differentiate into fibroblasts.
True
Which type of capillary has a pericyte associated with it?
Continuous Capillary
What are the three different capillary types?
Continuous, Fenestrated, and sinusoid (discontinuous capillary) capillaries.
Which two capillaries have a continuous basal lamina and which one does not?
Continuous Basal Lamina -> continuous and fenestrated capillaries.
Discontinuous Basal Lamina -> sinusoid (discontinuous) capillary
Give examples of where continuous capillaries can be found in the body?
> muscle > brain > thymus > bone > lung > pancreas
In which type of capillary would you expect to find caveolae and vesicles transporting substances through the cytoplasm in a bidirectional pathway (transcytosis)? HINT: the intra cytoplasmic vesicles are coated by the protein caveolin (haha).
Continuous Capillary
Where are fenestrated capillaries found in the body?
They are present in tissues with substantial fluid transport:
- intestinal villi (jejunum) - choroid plexus - ciliary processes of the eye - glomerular capillaries of the kidneys
Are the gaps larger in fenestrated or discontinuous capillaries?
Discontinuous capillaries (sinusoid)
Where are discontinuous capillaries commonly found in the body?
> Spleen -> endothelial cells are elongated and protrude into the lumen.
> Liver
True or False:
The gaps in venous sinusoids of the liver are wider than the discontinuous capillaries.
True
Does veins or arteries have a larger lumen? Also, how about the thickness of the vessel wall?
Veins have a larger lumen and thinner vessel walls.
True or False:
Larger veins do not have a layer of longitudinal smooth muscle in the inner aspect of the tunica adventitia.
False - larger veins have a layer of longitudinal smooth muscle in the inner aspect of the tunica adventitia.
List the general 4 step overview of the formation of an atherosclerotic plaque.
1) Endothelial Cell Dysfunction
2) Formation of the Atherosclerosis Plaque
3) T-cells-macrophage Interaction
4) Fracture of the Plaque and Thrombosis
