Cardiovascular system. Introduction

Introduction to the anatomy of the cardiovascular systemThe heart and vessels. Blood vessel types. The main peculiarities of the vascular structure. Blood circulation
~ 3 min

The cardiovascular system is a system of organs that ensures the delivery of substances necessary for vital activity to all tissues and cells of the human body.

Large and small circle of blood circulation
Large and small circle of blood circulation
Heart, aorta and its branches (front view)
Heart, aorta and its branches (front view)

Cardiovascular system

It consists of three components:

  • The heart (cor), which acts as a kind of pump for blood

  • Vessels (vasa), which perform a transport function by distributing blood throughout the body

  • And blood itself, which contains oxygen, as well as nutrients.

    Heart (cor)
    Heart (cor)
    Vessels (vasa)
    Vessels (vasa)

    Types of Circulation

    The heart, together with the vessels, forms two closed circuits, where two types of circulation take place.

    These two types of blood circulation are:

    The systemic circulation (circulus sanguinis major)

    Large (or systemic) circulation (circulus sanguinis major)
    Large (or systemic) circulation (circulus sanguinis major)

    The pulmonary circulation (circulus sanguinis minor)

    Pulmonary circulation (circulus sanguinis minor)
    Pulmonary circulation (circulus sanguinis minor)

    The pulmonary circulation delivers blood from the heart to the lungs, where it becomes saturated with oxygen and returns to the heart.

    The systemic circulation then delivers the blood to the organs and tissues, supplying them with oxygen and nutrients. The blood then returns to the heart, and the cycle repeats.

    The structure of the type of circulation is discussed in greater detail in the corresponding video.

    Heart: Chambers and Vessels

    The human heart consists of four chambers

    These are the left atrium (atrium sinistrum)

    The left ventricle (ventriculus sinister)

    The right atrium (atrium dextrum)

    And the right ventricle (ventriculus dexter)

    Left atrium (atrium sinistrum)
    Left atrium (atrium sinistrum)
    Left ventricle (ventriculus sinister)
    Left ventricle (ventriculus sinister)
    Right atrium (atrium dextrum)
    Right atrium (atrium dextrum)
    Right ventricle (ventriculus dexter)
    Right ventricle (ventriculus dexter)

    The right ventricle and left atrium are components of the pulmonary circulation, and the left ventricle and right atrium are components of the systemic circulation.

    The left atrium (atrium sinistrum)

    The left ventricle (ventriculus sinister)

    The right atrium (atrium dextrum)

    The right ventricle (ventriculus dexter)

    In addition, the heart itself is also supplied with blood by a system of coronary arteries. The largest of them are:

    The left coronary artery (arteria coronaria sinistra)

    And the right coronary artery (arteria coronaria dextra)

    Left coronary artery (arteria coronaria sinistra)
    Left coronary artery (arteria coronaria sinistra)
    Right coronary artery (arteria coronaria dextra)
    Right coronary artery (arteria coronaria dextra)

    Vessel Wall

    The vessel is a hollow tube with its own wall.

    Let’s consider the general outline of the structure of the vascular wall. It consists of three tunicae:

    The tunica externa or adventitia (tunica adventitia or tunica externa) mainly contains connective tissue elements

    The tunica media (tunica media) usually contains muscle cells

    The tunica intima (tunica intima) consists of a special type of epithelial tissue called the endothelium

    Adventitia (tunica adventitia or tunica externa)
    Adventitia (tunica adventitia or tunica externa)
    Adventitia (tunica adventitia or tunica externa)
    Adventitia (tunica adventitia or tunica externa)
    tunica media (tunica media)
    tunica media (tunica media)
    tunica media (tunica media)
    tunica media (tunica media)
    Tunica intima (tunica intima)
    Tunica intima (tunica intima)
    Tunica intima (tunica intima)
    Tunica intima (tunica intima)

    Classification of Vessels

    Let’s consider the main classifications of vessels.

    Based on their function, there are three types of vessels: Arteries (arteriae), which carry blood away from the heart Veins (venae), which carry blood towards the heart

    Capillaries (vasa capillaria), which connect arteries and veins between each other, and are also a place of exchange of oxygen and nutrients between blood and tissues

    Arteries (arteriae)
    Arteries (arteriae)
    Veins (venae)
    Veins (venae)
    Capillaries (vasa capillaria)
    Capillaries (vasa capillaria)

    There are also several separate types of arteries:

    Elastic arteries are mainly major vessels. They contain a large amount of elastic fibers, which provide resistance to blood pressure on the walls of blood vessels

    Mixed-type arteries are arteries of a slightly smaller caliber than the previous ones. They contain approximately equal amounts of elastic and muscular elements

    Muscular arteries constitute the majority of the arteries. They contain mainly muscle fibers and are involved in maintaining blood pressure.

    Elastic type arteries – aorta
    Elastic type arteries – aorta
    Mixed artery – subclavian artery
    Mixed artery – subclavian artery
    Muscular artery – radial artery
    Muscular artery – radial artery

    Veins are also divided into several types:

    Muscle-free veins, which virtually do not contain muscle elements in their wall. At the same time, the walls of such vessels do not collapse due to being located in the thickness of the organs.

    Muscleless veins (meningeal veins)
    Muscleless veins (meningeal veins)

    Muscular veins contain a different number of muscle elements in their wall, on the basis of which they are divided into:

  • Veins with a high content of muscle elements. These veins have valves (except for some) and are located in the inferior part of the trunk.

  • Veins with an average content of muscle elements. Most of them lack valves and are located in the lower extremities

  • Veins with a low content of muscle elements. They are located in the superior part of the trunk.

With a high content of muscle elements
With a high content of muscle elements
Femoral vein
With an average content of muscle elements
With an average content of muscle elements
Bachial veins
With a low content of muscle elements
Superior vena cava
With a low content of muscle elements

The last type of vessels are capillaries, they are an integral part of the so-called microcirculatory bloodstream. Thi s the place where the connection between arteries and veins, as well as the exchange of oxygen and nutrients be

Capillaries (vasa capillaria). They are part of the microcirculatory bloodstream

Capillaries (vasa capillaria)
Capillaries (vasa capillaria)

The microcirculatory bloodstream consists of the following elements:

Arterioles (these are very small arteries)

Precapillaries

Capillaries

Postcapillaries

Venules (these are very small veins)

Capillaries of the superior half of the body
Capillaries of the superior half of the body
Intestinal capillaries
Intestinal capillaries
Pulmonary capillaries
Pulmonary capillaries
Capillaries of the inferior half of the body
Capillaries of the inferior half of the body
Dictionary

Introduction to the anatomy of the cardiovascular system

Heart
cor
Vessels
vasa
Arteries
arteriae
Veins
venae
Tunica externa/adventitia
tunica adventitia/tunica externa
Tunica media
tunica media
Tunica intima
tunica intima
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