CIRCULATORY SYSTEM AND EXCRETORY SYSTEM

THE BLOOD VESSELS

THE CIRCULATORY SYSTEM

THE LYMPHATIC SYSTEM

THE HEART

Three types of them:

Arteries

Capillaries

  • Is an internal transport system that use to move nutrients, hormones, oxygen and other substances inside the body.


  • It is the way the internal milieu is renewed, that is the medium all the cells live. This medium gives the cells all the nutrients that they need and the cells also excrete the waste products released during metabolism through it.

Veins

Components:

It's the organ that pumps the blood inside of the blood vessels. The heart is made of a powerful wall of muscular tissue called the myocardium.

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A liquid: the blood

A group of tubes: the blood vessels, which bloods run through.

Three types of blood vessels: arteries, veins and capillaries.

A bomb that moves the blood through the blood vessels: the heart.

It is a complementary system of the circulatory system.The lymphatic system collect excess interstitial plasma made by the lymph and returns it to the blood.

THE BLOOD

  • The blood is a tissue, the only that is liquid. It is a viscous fluid with a salty taste. The human body contains around 5,5 liters of blood.

Composition:

BLOOD PLASMA: Is a yellowish substance made of water containing various dissolved molecules: mineral salts, nutrients, waste products.

The heart therefore has two atria and two ventricles.

Between the atrium and the ventricle on each side there is a valve: the atrioventricular valve.

The heart is divided into two halves, right and left, by an internal wall.The two halves are not connected in any way..

The blood enters the heart through the atrium by veins and leaves the heart from the ventricles through arteries .

BLOOD CELLS: There are three types of blood cells: Erythrocytes, Leukocytes and Trombocytes.

Erythrocytes or red blood cells:
They are disk-shaped and have no nucleus. They contain hemoglobin and a red pigment responsible for the blood’s red colour which transports oxygen from the alveoli of the lungs to the rest of the body’s cells. There are around 5 million per mm3 of blood.

Leukocytes or white blood cells:
There are different types (neutrophils, eosinophils, basophils, lymphocytes and monocytes) and all of them help to protect the body from infection. There are around 7000 per mm3 of blood.

Trombocytes or platelets:
They aren’t true cells, they are cell fragments. They contain substances that allow the blood to clot, preventing hemorrhages. There are around 300000 per mm3 of blood.

Functions:

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They carry the blood away from the heart. As they get further away from the heart, they gradually branch out into narrower vessels leading to the different organs. These vessels then divide into even smaller ones called arterioles.

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It transports nutrients and oxygen to all cells.

It transports hormones, which play an essential role in controlling bodily functions.

It collects waste products released during cell metabolism, like urea, uric acid and carbon dioxide.

It helps to regulate temperature. The blood works like a central heating system, moving body heat from the warm areas to the cooler ones.

It plays an essential role in protecting the body from infection.

It takes part in the process of blood coagulation or blood clotting. It is a mechanism to prevent blood loss when a blood vessel is broken.

Group systems:

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People have different types of blood; it depends on different proteins located in the membranes of red blood cells.

In a transfusion we need take into account both systems.

Functions

  • It collects the excess of interstitial plasma and returns it to the blood.
  • It helps to protect the body from infection.
  • It collects the products of fat digestion from the small intestine.

These are microscopic blood vessels which branch out from the arterioles and are found in every body tissue.

Their walls are formed by a single layer of flat cells which allow substances tobe exchanged quickly between the blood and the cells.

The ABO system: this is made of four blood types: A, B, AB and O.


The rh system; it can be positive or negative.

Is made of:

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Capillaries come together to form thicker venules. The venules then form veins.

These veins take blood back to the heart.

There are valves inside the veins which allow blood to flow towards the heart

but not in the opposite direction.

The lymph, lymph vessels and lymph nodes.

Lymph capillaries

Lymph veins.

It carries the blood to cells of the organs except

It carries the blood to the lungs.