The Cardiovascular system, Blood Vessels Anatomy
Pulmonary Circulation

Specialized Lecture in Anatomy & Physiology
مناقشة إسماعيل مرتضى  Discussed by Ismail Mortada

The Major reference for the this lecture & the following lectures in the same subject is
"Human Anatomy & Physiology" For Elaine N.Marieb the 5′th Edition
+ Internet + My personal University Lecture Notes

Please press on the pictures to be able to see them in larger sizes so that to read the contents

As it is known that the cardiovascular system is composed of 2 major components which are the Heart & the Vascular System it self "The Blood Vessels" in which they complete each other within the dynamic physiology in the human body & in other creatures also on this earth & my basic aim now in those lectures is to revise the names, locations & brief physiology of the blood vessels in the human body

Excluding the heart anatomy & physiology, it comes directly the vascular system which is made up of a blend of different kinds of arteries & veins which are used to transport different forms of the blood & nutrient from & to the heart & within the entire community of the human body cells , the circulation is made up of 2 basic sections which are as the following
A) The Pulmonary Circulation
B) The Systemic Circulation

A) The Pulmonary Circulation

Now, Considering the blood which is poor in oxygen & coming from all over the body cells & tissues toward the heart, it will enter the RIGHT ATRIUM of the heart & from it, it will be pumped to the RIGHT VENTRICLE & from there it will be sent into what is called the "Pulmonary Trunk", which runs diagonally upward for about 8 cm & then will be divided into the RIGHT & LEFT PULMONARY ARTERIES; Further to that, those pulmonary arteries will be divided inside the lungs to form the Lobar arteries in which there are 3 lobar arteries in the right lung & 2 lobar arteries in the left lung each one of the general 5 lobar arteries serves one lung lobe respectively, from the lobar arteries it branches to form the ARTERIOLES & then finally to give the PULMONARY CAPILLARIES that surround the air sacs & it is there in the smallest capillaries where the gases exchange will start in the human body

Note that people are used to use the word arterie for the blood vessel which carries pure oxygenated blood, but this is not the case here neither it is the right description for what’s exactly going on in anatomy & physiology, since in the systemic circulation, arterie would be any vessel which carries blood from the heart to any cell or tissue in the human body from which also is the lungs, so the blood entering the lungs "in the pulmonary circulation" coming from the tissues and poorly oxygenated is still called arterie and the blood leaving the lungs to the heart is called the veins, so in the pulmonary circulation the veins are the one who carries the oxygenated blood toward the left heart atrium & the arteries are those going out from the right heart ventricle toward the lungs, this is an important note in anatomy & physiology to be always considered & in addition to that any vessel which contains in its name the word "Pulmonary" or "Lobar" means that it belongs to the Pulmonary Circulation or the lungs & doesn’t belong to the Systemic Circulation

So as a faster brief to the mentioned information below we can say the following
A) The poor oxygenated blood will enter the Right lobe of the heart to the right atrium
B) Then it will be sent or pumped from the right heart atrium to the right heart ventricle
C) Then it will be pumped to the Pulmonary Trunk
D) From the pulmonary trunk it will be sent to both the left & the right pulmonary arteries
E) The pulmonary arterie will form what is called the Lobar Arteries in which they are basically 5 in numbers
F) The lobar arteries are 3 arteries in the right lungs serving 3 lobes
G) The lobar arteries are forming 2 arteries in the left lung serving the lobes there aloso & the totall as mentioned before are 5 alobar arteries
H) Then the lobar arteries will divide forming smaller Arterioles
I) Then the arterioles will form the smalles Pulmonary Capillaries where the gas exchange will occur

In the alveoli or the air sacs in the lungs, the oxygen exchange will occur & the blood will become brighter red in color "due to the hemoglobin change & iron state change & oxygen availability" so in this case the blood will keep on moving from the pulmonary capillaries into the VENULES, from which it will form the PULMONARY VEINS exiting from each lung lobe, so in total there are 4 pulmonary veins arising from the lungs in general all of which moves toward the left heart atrium

Please watch the following videos which are related in a way or other to the subject of this lecture