Major and minor circulation

The major or systemic circulation is the circuit or path that the blood makes from the heart to the body and back to the heart, while the minor or pulmonary circulation is the circuit that carries the blood from the heart to the lungs and then to the heart .

In the greater circulation, the blood travels through the arteries and arterioles, until it reaches the capillaries, where they release oxygen and capture carbon dioxide from the tissues. Then the capillaries are grouped into venules and continue in the main veins until they reach the right atrium.

In the minor circulation, blood travels from the right ventricle to the pulmonary arteries, which capillary in the lungs, where the release of carbon dioxide and oxygen uptake take place, returning oxygenated blood through the pulmonary veins to the left atrium. from the heart.

Greater circulationLess circulation
DefinitionA circuit of blood circulation that distributes oxygenated blood through the body from the heart.Circuit of blood circulation that carries deoxygenated blood to the lungs.
SynonymousSystemic circulation, peripheral circulation.Pulmonary circulation
Blood volume84% of the total blood volume: 64% in the veins, 13% in the arteries.16% of the total blood volume: 7% in the heart and 9% in the lungs.
  • Supply tissues with oxygen and other nutrients.
  • Transport hormones to your target organs.
  • Collect carbon dioxide and other wastes generated by metabolism.
  • Exchange the carbon dioxide in the red blood cells for oxygen from the air in the lungs.
Where the blood travelsHeart (left ventricle) → aorta artery → peripheral arteries → tissue capillaries → peripheral veins → Vena cava → heart (right atrium).Heart (right ventricle) → pulmonary arteries → alveolar capillaries → pulmonary veins → heart (left atrium).
Major arteries
  • Aorta
  • Carotids
  • Renal
  • Iliac
Pulmonary artery
Important veins
  • Cava: top and bottom.
  • Brings.
  • Renal: right and left.
Pulmonary veins
Blood pressureSystolic blood pressure: 120mm Hg.

Diastolic blood pressure: 80mm Hg.

Systolic pulmonary artery pressure: 25mm Hg.

Diastolic pulmonary artery pressure: 8mm Hg.

Time of residence of the blood in the capillariesBlood takes between 1 and 3 seconds in the systemic capillaries.Blood takes about 0.8 seconds to the pulmonary capillaries.
Gas exchangeOxygen is exchanged from the red blood cells to the tissues for carbon dioxide from the tissues to the red blood cells.Carbon dioxide is exchanged from the red blood cells to the alveoli for oxygen from the alveoli to the red blood cells.

Major or systemic circulation

The major or systemic circulation is the part of the blood circulation that carries oxygenated blood from the heart to the whole body, and returns the deoxygenated blood to the heart.

Characteristics of the major circulation

  • Of the total volume of blood in the human body it represents 84%, distributed 64% in the veins and 13% in the arteries.
  • It begins with the contraction of the left ventricle of the heart after it receives oxygenated blood from the left atrium (atrium) and directs it to the aorta.
  • It culminates in the arrival of deoxygenated venous blood to the right atrium through the superior vena cava and inferior cava.

Function of the major circulation

The major circulation is responsible for:

  • the distribution of oxygenated blood to tissues.
  • The collection of waste substances from tissues.
  • Sending deoxygenated blood back to the heart.
  • The distribution of hormones from your production glands to your target organs.

Minor or pulmonary circulation

The minor or pulmonary circulation is the part of the circulation that carries deoxygenated blood from the heart to the lungs and returns oxygenated blood to the heart.

Characteristics of pulmonary or minor circulation

  • It begins in the right ventricle of the heart , after it fills with venous blood from the right atrium (right atrium).
  • It represents 16% of the total blood volume, 7% in the heart and 9% in the lungs.
  • The time that the blood remains in the pulmonary capillaries is 0.8 seconds, that is, in less than one second the blood loses carbon dioxide and is charged with oxygen.
  • In a normal human being, the systolic pressure of the pulmonary artery is 25mm Hg; the diastolic pressure of the pulmonary artery is 8mm Hg.

Function of the minor circulation

The main or minor function of pulmonary circulation is gas exchange at the level of the pulmonary alveoli :

  • the blood that carries carbon dioxide passes through the fine pulmonary capillaries and the carbon dioxide is released from the red blood cells and passes into the alveolus, to then be expelled on expiration.
  • Simultaneously, the oxygen that enters the alveoli through inspiration passes into the capillaries and enters the red blood cells.

You may also be interested in seeing the difference between veins and arteries .

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