INTRODUCTION TO HYPERTENSION: AN OVERVIEW TO THE ANATOMY AND PHYSIOLOGY TO THE HEART

An Overview

Hey readers!! I am Sarang More an Edublogger and student. So in today’s video we are going to discuss about the PATHOPHYSIOLOGY of Hypertension.

But, but, but before jumping into the actual concept it is very essential to know about the organ or the system in which the actual hypertension will be causing i.e. in heart obviously but more specifically in the arteries or the blood vessels.

So in this article we are going to study about the CARDIOLOGY.

Coming to the heart, it is relatively small, conical in shape and roughly as the size of one’s fist (not always possible). It is 12cm in length and 9cm in breath and 6cm thick. It weighs 250gm in adult females while in males it weighs about 300gm.

The heart rest on diaphragm, near the midline of thoracic cavity known as mediastinum. Actually, the heart is slightly tilted towards left so it is said that heart is positioned to the left side. One more astounding fact about the heart is it is placed inverted in position, means the tip of the heart is near towards the left ventricle (the lower chamber of the heart).

The base of the heart is opposite the apex and is its posterior aspect.

More detailing it can be visualized the anterior surface is deep to the sternum and ribs.

The inferior surface is the part of the heart between the apex and right surface and rests mostly on the diaphragm.

The right surface faces the right lung and extends from the interior surface to the base. The left surface faces the left lung and extends from the base to the apex.

PERICARDIUM:-

As we are going to discuss about the endocarditis and pericarditis later so we will discuss what is pericardium.

So the pericardium is the membrane which surrounds and protects the heart. It consists of two parts: -

1. Fibrous pericardium

2. Serous pericardium

The superficial fibrous pericardium composed of tough, inelastic, dense irregular connective tissue.

The fibrous pericardium prevents the overstretching of the heart, provides protection and anchors the heart in the mediastinum. The fibrous pericardium is partially fused with central tendon of the diaphragm which facilitates the movement of blood with the heart with deep breathing.

The deeper serous pericardium is a thinner, more delicate membrane which forms a double layer around the heart.

The outer serous pericardium is known as parietal layer whereas the inner layer is known as visceral layer of serous pericardium, which is also known as epicardium.

Between the parietal layer and visceral layer is present the pericardial cavity which is filled with the pericardial fluid which lubricates the hearts while pumping.

This was the outer layer of the heart, as it is the visceral layer so it extra protection is extremely necessary.

Now the discussion is about the layers of the heart, the heart is composed of three layers,

Outer Epicardium

Middle Myocardium

Inner Endocardium

As we mind boggled over there, the epicardium is composed of visceral layer of parietal layer.

It is thin layer composed of mesothelium, beneath is various layer of delicate fibroelastic tissue and adipose tissue.

The adipose tissue further thickens at the ventricles, also the coronary and cardiac vessels (basically the blood vessels).

The epicardium is supplied with blood vessel and lymphatics which supply to the myocardium.

The middle myocardium is the main hero tissue of the heart which makes up the pumping muscle tissue. It composes of 95% of total thickness of heart wall. These striated skeletal muscle tissue are wrapped with bundle of connective tissue sheaths composed of endomysium and perimysium.

The pumping action is brought by swirling of the bundles diagonally, which is involuntary in function.

The innermost endocardium, is a thin mainly composed of endothelium overlying with smooth lining of connective tissue.

It continues to the chamber of heart along with valves which minimizes the friction as blood passes through the heart. It also lines the major arteries which connects to the heart directly.

CHAMBERS OF THE HEART:-

Unlike other mammal, the human heart is four (4) chambered. The two superior receiving chambers known as Atria or auricle, and two inferior pumping chambers are known as Ventricles.

The atria receives the deoxygenated blood from veins, primarily the superior venacava, Inferior venacava and the coronary Sinus.

While the ventricles eject the oxygenated blood from itself to arteries primarily the Systemic trunk. The heart also has the series of grooves known as Sulci which holds the coronary blood vessels and a variable amount of fat. Along with that the coronary sulcus also differentiate the chambers (auricle and ventricles) from each other.

The coronary sulcus also marks the external boundary between ventricles on the posterior aspect of the heart.

RIGHT ATRIUM:

The right atrium forms the right side of the heart receives the deoxygenated blood from superior venacava, inferior venacava and from heart itself coronary sinus. The right atrium is about 2- 3mm average in the thickness.

The anterior and posterior regions of the right atrium is very different. The posterior region is smooth but the anterior region is rough due to presence of muscular ridges called as pectinate muscles.

The right atrium is differentiated from left atrium by inter- atrial septum a thin lining which separates the two atrium. A prominent feature of this septum is fossa ovalis a remnant of foramen ovale, an opening in the interatrial septum of the fetal heart that closes soon after birth normally.

The flow of blood form right atrium to the right ventricle is form tricuspid valve which is made up of dense connective tissue.

RIGHT VENTRICLE:

The right ventricle is 4-5 mm in thickness in average and it forms the anterior surface of the heart. Inside the ventricles we might like to see the trabeculae carneae. The tricuspid valve is connected to the ventricles by chordae tendineae, which are connected to the trabeculae carneae called papillary muscles.

The right ventricle is divided from left ventricle by interventricular septum. The deoxygenated blood from right ventricles passes to the pulmonary trunk, which divides into left and right pulmonary artery and carries blood to the lungs.

LEFT ATRIUM:

The left atrium is of same thickness as the right atrium. It receives the oxygenated blood from four pairs of pulmonary veins. Blood passes from left atrium to the left ventricle through Bicuspid valve (mitral valve), which has two flaps. It is also known as left atrioventricular valve.

LEFT VENTRICLE:

The left ventricle is the thickest chamber of the heart, about 10- 15mm in diameter average. It forms apex of the heart.

Like the right ventricle it also contains trabeculae carneae and has chordae tendineae that anchors the bicuspid valve to papillary muscles.

The blood flow from left ventricle to the systemic aorta which supplies the oxygenated blood to the whole body. The oxygenated blood is also supplied to the heart muscles itself by coronary artery.

So that's for it today, if you like my blog please let me know in the comment section and stay tuned for my next blog on hypertension.