Cardio Histology Flashcards
Components of the cardiovascular system
Heart Arteries Veins Capillaries Lymphatic vessels
Layers of the heart
Epicardium Myocardium Endocardium
Components of Epicardium
Mesothelial lining Connective Tissue Underlying the mesothelium
Mesothelial Lining of the epicardium
covers the external surface of the heart
Connective tissue underlying mesothelium of the epicardium
Loose connective tissue, adipose tissue Nerves pass through this layer Blood vessels travel to the myocardium through this layer
Principle component of heart wall
Myocardium (thickest layer)
Thickness of myocardium in the atria vs ventricles
Thicker in the ventricles
Most internal layer of the heart
Endocardium
Components of endocardium
endothelium subendothelial connective tissue impulse conducting system
Describe the internal skeleton of the heart
Four fibrous rings that surround the valve orifecesAll within the atrioventricular plane (one continuous sheet)
Purpose of a trigone
to connect fibrous tissue rings surrounding valves together
left atrioventricular rings surrounds what valve
Mitral valve
Right atrioventricular ring surrounds what valve
Tricuspid
Left trigone connects what?
left atrioventricular ring (mitral) and aortic fibrous rings
Right trigone connects what?
left (mitral) and right (tricuspid) atrioventricular rings
Membranous Part of the interventricular septum
Devoid of cardiac muscle Composed of dense irregular connective tissue Contains part of the AV bundle
Where dies Ventricular Septal Defect occur
in the membranous portion of the IV septum
layers of valves
1: Fibrosa2: Spongiosa 3: Atrialis
Fibrosa
formed of DICT connected to corresponding fibrous ring Extends form the base along the ventricular side of atrioventricular valves
Which layer of the valve faces the ventricular side of the atrioventricular valve
fibrosa
Spongiosa
Formed of loose connective tissue large amounts of elastic fibers Most prominent on free edges of the valve
Where do you find the spongiosa layer of the valve, what is the purpose of this layer
most prominent on the free edges Purpose: shock absorption (dampens vibrations as the valve closes)
Atrialis
covers the atrial aspect of spongiosaRich in proteoglycans Contains elastic fibers and occasional smooth muscle cells
What layers of the valve contain elastic fibers
Spongiosa Atrialis
Which layer(s) of the valve (may) contains some smooth muscle cells?
Atrialis
Mirtal Valve stenosis
inflammation of valve leaflets that promotes angiogenesis leading to formation of fibrotic tissue resulting in stenosis of the valve Rheumatic fever can be a cause
Describe the ANS and heartbeat
ANS can REGULATE the heart beat but it does not INITIATE heartbeat
Parasympathetic - HR
Decrease HR
Sympathetic- HR
Increases HR
Effect of hormones and other substances on HR
can change the rate and force of contraction ex: Epinephrine, thyroid hormones, caffeine
What are cardiac conducting cells called
Purkinje Fibers
Describe Purkinje fibers
modified cardiac myocyte (modified to conduct electrical impulses) contain a lot of glycogen can transmit faster than myocytes still have intercalated discs