Pericardium and Heart
In its typical anatomical orientation, the heart has 5 surfaces, formed by different internal divisions of the heart what are they?
Anterior (or sternocostal) - Right ventricle Posterior (or base) - Left atrium Inferior (or diaphragmatic) - Left and right ventricles Right pulmonary - Right atrium Left pulmonary - Left ventricle
What 3 kinds of trabecular carneae are there?
Attached to the ventricle wall at both ends (forming a bridge) Attached to the ventricle wall along their length (forming a ridge) Attached to the ventricle wall at their base, and to chordae tedineae at the other end. These are known as papillary muscles.
What comes off the arch of the aorta?
Brachiocephalic artery - supplies blood to the brain, head, and the right side of the thorax. Left common carotid artery - supplies blood to the left side of the neck and head. Left subclavian artery - supplies blood to the left side of the thorax.
Fibrous Pericardium characteristics
Continuous with the central tendon of the diaphragm, the fibrous pericardium is made of tough connective tissue and is relatively nondistensible. This rigidity prevents rapid overfilling of the heart
Serous Percardium characteristics
Enclosed within the fibrous pericardium, the serous pericardium is itself divided into two layers - the outer parietal layer which lines the internal surface of the fibrous pericardium and the internal visceral layer which forms the outer layer of the heart (also known as the epicardium). Each layer is made up of a single sheet of epithelial cells, known as mesothelium.
What are the three layers of the heart?
Endocardium, Myocardium, and Epicardium.
What is the cardiac skeleton what is its purpose?
Fibrous skeleton of the heart - crisscrossing, interlacing layer of connective tissue, Consists of fibrous and fibrocartilaginous tissue that surrounds the atrioventricular and semilunar openings, Gives attachments to the valves and the interventricular septum, prevents over dilation. All muscles EXCEPT papillary muscles insert on the skeleton. Serves as the electrical insulator between the atria and the ventricles.
What is the pericardial cavity?
Found between the parietal and visceral serous layers, is the pericardial cavity, which contains a small amount of lubricating serous fluid. This fluid serves to minimize the friction generated by the heart as it contracts and moves about within the thoracic cavity.
How many papillary muscles of in the Left ventricle and what do they do?
In the left ventricle there are two papillary muscles, which are larger than those found in the right. They are attached to the chordae tendinae, which in turn attach to the mitral valve.
what are the two parts of the atrium like?
Inflow portion - This part receives blood from the pulmonary veins. Its internal surface is smooth. It is derived from the pulmonary veins themselves Outflow portion - This part is located anteriorly, where the blood flows into the ventricles. It contains the pectinate muscles and the left auricle. It is derived from the embryonic atrium. Has less pectinate muscles than the Right atrium
What does the pericardium do?
Limits to movement of the heart, Prevents overfilling of the heart because the fibrous pericardium is not descendable, Lubrication, and Protection from infection - The fibrous pericardium serves as a physical barrier between the muscular body of the heart and adjacent organs prone to infection, such as the lungs.
Myocardium
Muscle part of the heart, striated involuntary cardiac muscle
What are the borders of the heart?
Right border=Right Atrium Inferior border= Right and Left Ventricle Left border= Left ventricle and some of Left atrium Superior border= Left and Right atrium and great vessels
What are the two sulci and what do they represent?
The anterior and posterior interventricular sulci can be found running vertically on their respective sides of the heart. They represent the wall separating the ventricles.
What does the aorta do what is its route?
The aorta receives oxygenated blood from the lungs, and delivers it to the body. It begins at the left ventricle, from which it is separated by the aortic valve. It then curves laterally, towards the left, forming the arch of aorta. After the arch of the aorta, the aorta then becomes the descending aorta becoming the thoracic and abdominal aorta.
What is the coronary sinus?
The coronary sinus runs transversely around the heart - it represents the wall dividing the atria from the ventricles. The sinus contains important vasculature, such as the right coronary artery.
What are the sulci of the heart?
The heart is a hollow structure. On the interior, it is divided into four chambers. These divisions create grooves on the surface of the heart - these are known as sulci.
Inferior Vena cava what does it do?
The inferior vena cava receives deoxygenated blood from the lower body, and delivers it to the right atrium. It is formed in the pelvis by the common iliac veins joining together. It travels through the abdomen, collecting blood from hepatic veins, lumbar veins, gonadal veins, renal veins and phrenic veins. The inferior vena cava then drains into the inferior portion of the right atrium.
What is the inflow part of the ventricle lined with?
The interior of the inflow part of the right ventricle is covered by irregular muscular structures, called trabeculae carneae. They give the ventricle a 'sponge-like' appearance.
What is the crista terminalis?
The interior surface of the right atrium can be divided into two parts, each with a distinct embryological origin. They are divided by a smooth muscular ridge, called the crista terminals. Posterior to the crista terminalis: This part receives blood from the vena cavae. It has smooth walls and is derived from the embryonic sinus venous. Anterior to the crista terminalis: This part is derived from the primitive atrium. Internally, it has muscular walls, formed by pectinate muscles. It also contains the right auricle.
what does the Left atrium do?
The left atrium receives oxygenated blood from the pulmonary veins. In the anatomical position, it forms the posterior border of the heart. Blood is pumped from the left atrium into the left ventricle, via the mitral valve.
Left Ventricle
The left ventricle receives oxygenated blood from the left atrium, and expels it into the aorta. It is located anteriorly to the left atrium, contributing to the anterior aspect of the heart, and forming the apex. To pump blood into the aorta, and around the body, the ventricle must create a high pressure. As such, it has thicker muscular walls than the right ventricle. The interventricular septum is part of the left ventricle.
Describe the outflow portion of the right ventricle
The outflow part (leading to the pulmonary artery) is located in the superior aspect of the ventricle. It is called the conus arteriosus, and is derived from the embryonic bulbus cordis. It is visibly different from the rest of the ventricle, having smooth walls, with no trabeculae carneae.
What is the outflow portion of the left ventricle and what is it derived from?
The outflow part of the left ventricle is known as the aortic vestibule. It is smooth-walled, and a derivative of the embryonic bulbus cordis.
What is the pericardium?
The pericardium is a fibroserous, fluid filled sack that surrounds the muscular body of the heart and the roots of the great vessels (the aorta, pulmonary artery, pulmonary vein and the superior and inferior vena cava).
What are the two layers of the pericardium?
The pericardium is made up of two main layers - a tough external layer known as the fibrous pericardium, and a thin, internal layer known as the serous pericardium
What does the Right atrium do?
The right atrium receives deoxygenated blood from the superior and inferior vena cava. It also receives drainage from the coronary veins via the coronary sinus. The atrium pumps this blood to the right ventricle.
What is the right auricle?
The right auricle (also known as the right atrial appendage) is located on the anteromedial portion of the right atrium, overlapping the root of the aorta. It acts to increase the capacity of the right atrium.
Right Ventricle
The right ventricle receives deoxygenated blood from the right atrium, and pumps it into the pulmonary artery. The ventricle is triangular in shape, and forms the majority of the anterior border of the heart.
What does the Superior Vena cava do and what is its path?
The superior vena cava receives deoxygenated blood from the upper body, and delivers it to the right atrium. the maxillary and superficial temporal veins drain into the retromandibular vein (posterior branch) which drains along with the posterior auricular vein int0 the external jugular which drains into the subclavian that drains into the brachiocephalic vein-> the right and left brachiocephalic drain into the Superior Vena Cava. Sigmoid Sinus->Internal jugular vein out the jugular foramen-> (during descending down the neck gets blood from facial, lingual, occipital, superior and middle thyroid veins)->internal jugular combines with the subclavian vein to make the brachiocephalic vein->the right and left brachiocephalic veins combine to make the superior vena cava.
what is the triangle of koch?
The triangle of Koch is a triangle in the the right atrium which is an important anatomical landmark to help find the location of the AV node.
How many papillary muscles are in the Right Ventricle? What do they do?
There are three papillary muscles in the right ventricle. They are attached to chordae tendineae (fibrous cords), which are in turn attached to the tricuspid valve. By contracting, the papillary muscles 'pull' on the chordae tendineae, and prevent the valve from regurgitating during ventricular contraction.
What is the moderator band?
There is a large muscular structure that runs between the interventricular septum and the anterior wall of the right ventricle. It is called the moderator band. It has an important conductive function, containing right bundle branches
What is the pericardial sinus?
They are passageways formed the unique way in which the pericardium folds around the great vessels. The oblique pericardial sinus is a blind ending passageway ('cul de sac') located on the posterior surface of the heart. The transverse pericardial sinus separates the arterial vessels (aorta, pulmonary trunk) and the venous vessels (superior vena cava, pulmonary veins) of the heart.
How is the pericardium innervated?
Visceral sensory fibers given off by the branches of 'phrenic nerve', innervate the fibrous pericardium as well as the parietal layer of serous pericardium. These fibers generally carry the sensation of pain. Parasympathetic fibers that are responsible for slowing down of the heart rate, arise as branches of the Vagus nerve in the neck and thorax and innervate the visceral layer of serous pericardium. Sympathetic fibers that increase the rate and force of contraction travel to the heart from the cervical and upper thoracic sympathetic chain of ganglia and innervate the visceral layer of serous pericardium just like the sympathetic fibers.
what do pectinate muscles do?
allow atria to fill up and stretch without stress on walls
What lines the valves?
endocardium
what is the Septomarginal trabecula
in the right ventricle: Surface projection of muscle that runs from the interventricular septum to the base of one of the papillary muscles, it carries a branch of the cardiac conduction system to the papillary muscles
Pericardial Effusion and Cardiac Tamponade
increased fluid in the pericardial cavity leads to pericardial effusion and fibrous pericardium doesn't stretch so increased pressure in the heart (cardiac tamponade) the chambers of the heart become compressed and you get a decreased cardiac output.
What is the subendocardial layer?
layer between the endocardium and myocardium where purkinje fibers are located. As the subendocardial layer houses the conducting system of the heart, damage to this layer can result in various arrhythmias.
Blood supply of pericardium
the pericardiophrenic artery coming off the internal thoracic artery that comes off the subclavian artery
What is another name for the epicardium?
visceral serous pericardium.
