Cardiorenal I Flashcards
(76 cards)
Epicardium
the most external layer of the heart wall and is also called the visceral layer of the serous pericardium. It includes the following components: -mesothelial lining -CT underneath

Myocardium
the principal component of the heart wall. It is formed by cardiac muscle. This part of the ventricles is substantially thicker than that of the atria

Endocardium
Is the most internal layer of the heart wall. It includes the following components: -endothelium -subendothelial CT -impulse conducting system of the heart

Mesothelial Lining (of myocardium)
covers the external surface of the heart

Connective Tissue underlying Myocardial Mesothelium
- Loose connective tissue, adipose tissue. 2. Nerves pass through this layer. 3. Blood vessels travel to the myocardium through this layer.

Endothelium of the heart
is the epithelium that lines the luminal surface of the heart.

Subendothelial CT
a thin sheath of connective tissue located directly beneath the endothelial lining
Impulse Conducting System
The deeper layer of subendo CT contains this nerve system
Fibrous Skeleton
Heart walls are supported by a well-developed fibrous skeleton that also extends into the valves. The internal fibrous skeleton of the heart consists of four fibrous rings that surround the valve orifices and two trigones, which connect the rings together. These structures are composed of dense irregular connective tissue
Fibrous ring of the pulmonary trunk
surrounds the base of the pulmonary trunk
Fibrous ring of the aorta
surrounds the root of the aorta
Left atrioventricular ring, or ring of the mitral valve
surrounds the left atrioventricular orifice
Right atrioventricular ring, or ring of the tricuspid valve
surrounds the right atrioventricular orifice
Left fibrous trigone connects
connects left atrioventricular and aortic fibrous rings
Right fibrous trigone connects
connects left and right atrioventricular fibrous rings
membranous part of the interventricular septum
devoid of cardiac muscle and is composed of dense irregular connective tissue. It contains part of the atrioventricular bundle
Valves
composed of connective tissue covered with endothelium. The loose connective tissue acts as a shock-absorber. Dense irregular connective tissue with elastic fibers provides structural support for the valve. Valves are composed of three layers: -Fibrosa -Spongiosa -Atrialis
Fibrosa
formed of dense irregular connective tissue connected to the corresponding fibrous ring. It extends from the base along the ventricular side of the atrioventricular valves.
Spongiosa
is sandwiched between the fibrosa and atrialis and forms the core of the valve. It is formed of loose connective tissue with large amount of elastic fibers. It is most prominent in the free edge of the valve and acts as a shock-absorber by dampening vibrations when the valve closes. A few adipose tissue cells may be seen within this layer occasionally.
Atrialis
covers the atrial aspect of the spongiosa. It is rich in proteoglycans and contains elastic fibers and occasional smooth muscle cells.
Clinical comment: mitral valve prolapse
is one of the most common valve pathologies affecting 5-10 % of the population worldwide. It is caused by the abnormal formation of structural proteins that form the valve, such as collagen or fibrillin. The mutation of fibrillin (one of the proteins that form elastic fibers) gene causes so-called Marfan syndrome. Patients with this syndrome tend to suffer from this condition.
Cardiac muscle contracts dependently/independently of nerve stimulation.
independently The innervation from the autonomic nervous system does not initiate the heartbeat, but regulates the heart rate
The heart rate can be altered by:
i. Parasympathetic nerves decrease the heart rate. ii. Sympathetic nerves increase the heart rate. iii. Hormones and other chemical substances can change the heart rate and force of contraction.
Examples that increase the force of contraction and increase the heart rate.
epinephrine, thyroid hormones, caffeine, and many other substances



