THE HUMAN CIRCULATORY SYSTEM

CONTENTS

-CIRCULATORY SYSTEM--THE HEART--THE BLOOD-

-THE BLOOD VESSELS--THE BLOOD CIRCUIT-

-THE LYMPHATIC SYSTEM-

* CONTENTS *

CIRCULATORY SYSTEM – Many human activities requires a continuous supply of materials such as oxygen, nutrients, enzymes, hormones, carbon dioxide, toxic products, and others which are transported to and from different body cells and tissues. The transport of materials is a vital function of the circulatory system. The system is made up of three parts namely:

1. The Human2. The Blood3. The Blood Vessels

The circulatory system is made up of the vessels and the muscles that help and control the flow of the blood around the body. This process is called circulation. The main parts of the system are the heart, arteries, capillaries and veins.As blood begins to circulate, it leaves the heart from the left ventricle and goes into the aorta. The aorta is the largest artery in the body. The blood leaving the aorta is full of oxygen. This is important for the cells in the brain and the body to do their work. The oxygen rich blood travels throughout the body in its system of arteries into the smallest arterioles. On its way back to the heart, the blood travels through a system of veins. As it reaches the lungs, the carbon dioxide (a waste product) is removed from the blood and replace with fresh oxygen that we have inhaled through the lungs.

CIRCULATORY SYSTEM

THE HEART

HEART There are many different parts of the heart. One of these parts is the atrium. There is also the aorta. The aorta is the main artery in the heart. It carries oxygen rich blood from the left side of the heart to places all over the body. You also have the ventricles. The ventricles are the both sides of the heart. The ventricles receive blood from the atrium, which contracts to push the blood out and into the ventricles. The ventricles supply blood to the body by pumping it out of the heart. The vena cava is a main vein in the body. It carries blood from the body to the right side of the heart.

Your heart's job is to pump blood around your body. Its muscles contract and squeeze out blood. The left-hand side pumps blood from the lungs to the rest of your body. The right-hand side pumps stale blood from your body back to your lungs for a fresh supply. They do not work on their own, but together as a team. The body's blood is circulated through the heart more than 1,000 times per day. Between five and six thousand quarts of blood are pumped each day. Your heart is about the same size as your fist.

WHAT HEART CAN DO ?

Blood is thicker than water and has a little bit salty taste. In an adults body there is 10.6 pints of blood circulating around. In their blood there is billions of living blood cells floating in a liquid called plasma. If you took a small sample of this blood and poured it into a test tube and then put it in a machine called a centrifuge, you would be able to see the layers of this blood. The red blood cells sink to the bottom because they are the heavier, more solid parts, but the plasma remains at the top because it is lighter. The plasma is 95% water and the other 5% is made up of dissolved substances including salts.

THE BLOOD

CELL TYPE:

1. Red Blood Cells (Erythrocytes)-

Transport oxygen and a small amount of carbon dioxide.

2. White Blood Cells (Leukocytes):

A. Neutrophil Destroy relatively small particles by phagocytosis.

B. Eosinophil Inactive inflammation producing substances. It attacks parasites.

C. Basophil Releases anticoagulant to prevent blood clots and histamine, which causes inflammation.

D. Monocyte Give rise to macrophage, which destroys relatively large particles by phagocytosis.

E. Lymphocytes Function in the immune system.

Eosinophil Basophil Neutrophil

Lymphocytes Monocyte

3. Platelet (thrombocytes) – This are small, irregularly shaped clearcell fragments (i.e. cells that do not have a nucleus containing DNA),. The average lifespan of a platelet is normally just 5 to 9 days. Platelets are a natural source of growth factors . They circulate in the blood of mammals and are involved in hemostasis , leading to the formation of blood clots .

Artery/Arteriole carries blood away from the heart.

THE BLOOD VESSELSVein / Venules carries blood towards the heart.

Artery Vein

VEINSVeins carry the blood to the heart. The smallest veins, also called venules, are very thin. They join larger veins that open into the heart. The veins carry dark red blood that doesn't have much oxygen. Veins have thin walls. They don't need to be as strong as the arteries because as blood is returned to the heart, it is under less pressure.

ARTERIES -Arteries are tough, elastic tubes that carry blood away from the heart. As the arteries move away from the heart, they divide into smaller vessels. The largest arteries are about as thick as a thumb. The smallest arteries are thinner than hair. These thinner arteries are called arterioles. Arteries carry bright red blood! The color comes from the oxygen that it carries.

The site of the exchange of materials between the blood and the body tissues.

Capillary

Pulmonary circulation is the half portion of the cardiovascular system which carries oxygen -depleted blood away from the heart, to the lungs , andreturns oxygenated (oxygen-rich) blood back to the heart.

THE BLOOD CIRCUITPulmonary circuit Systemic circuit

Systematic is the one that carries fully oxygenated blood from the heart going to the brain and body. The second order systemic output blood is selectively deoxygenated by the needs of the peripheral organs, returning once again to the heart .

BLOOD CIRCULATION

The lymphatic system is composed of a network of vessels, nodes, and organs. It collects intercellular fluid, cleans it, and returns it to the circulatory system. The work of the system prevents body tissues from becoming swollen with intercellular fluid.

THE LYMPHATIC SYSTEM

Components of lymphatic system:

1. Lymph Capillaries

2. Lymph Nodes

The lymph capillaries begin blindly in the tissue spaces and form intricate networks. This are absent from the cellular structures like brain, spinal cord, splenic pulp, and bone marrow. The superficial lymphatics accompany veins, while the deep lymphatics accompany arteries. The lymph passes through filters or barriers of the regional lymph nodes which trap the particulate matter. The filtered lymph passes through larger lymphatics and is eventually collected into two large trunks, the thoracic duct and right lymphatic duct, which pour their lymph into the brachiocephalic veins. Thoracic duct drains both lower limbs, abdomen, left halves of thorax, head and neck and left upper limb. Right lymphatic duct drains right halves of thorax, head and neck and right upper limb. Larger lymphatics are supplied with their vasa vasorum and are accompanied by a plexus of fine blood vessels which form red streaks seen in lymphangitis.

Lymph Capillaries

Lymph nodes are small nodules of lymphoid tissue found in the course of smaller lymphatics. The lymph passes through one or more lymph nodes before reaching the larger lymph trunks. The nodes are oval or reniform in shape, 1-25 mm long, and light brown, black (pulmonary), or creamy white (intestinal) in color. Usually they occur in groups (cervical, axillary, inguinal, mesenteric, mediastinal, etc.), but at times there may be a solitary lymph node. Each lymph node has a slight depression on one side, called hilum. The artery enters the node, and the vein with efferent lymphatic comes out of it, at the hilum. The afferent lymphatics enter the node at different parts of its periphery.

Lymph Nodes

Most of the disease-fighting function of the adult mammal is carried out by the Lymph Nodes. These are bean shaped, and occur along the lymph ducts. They serve as tiny filters, in which the lymphocyrtes actively attack any foreign substances that pass through the tiny spaces between cells.  There are many clusters of lymph nodes. The three shown in the illustration are the cervical lymph nodes (in the neck), the axillary lymph nodes (in the armpit), and the inguinal lymph nodes (in the groin). These three sets are called palpable lymph nodes, because they can be felt from the outside. Swelling of these nodes indicates infection.

Organs or structure in the body that function as an organ of the lymphatic system

The Thymus is a large gland that covers the top of the heart in children. Lymphocytes migrate to the thymus from the bone marrow, where they divide rapidly forming what are called T-lymphocytes (T for thymus). The T-lymphocytes then migrate to other lymphatic organs where they mature and divide further. After puberty, the thymus degenerates slowly. Its role appears to be more concerned with setting up the immune system, while the actual disease fighting properties are carried out elsewhere. 

Three pairs of enlarged lymph nodes called Tonsils occur in the pharynx (chamber at the back of the nose and mouth). The pharyngeal tonsils, also called adenoids, are at the back of the sinuses, the palatine tonsils are in the palate that separates the nasal and oral cavities, and the lingual tonsils are at the base of the tongue. The tonsils seem to play an important role in the immune response in children.

The Spleen is an interface between the blood and the lymphatic system. Knots of lymphatic tissue in the spleen add lymphocytes to the blood. The spleen also acts as a filter for the blood, and helps to destroy worn out red-blood cells. In the event of damage to the spleen, it can be removed and its functions will be carried out reasonably effectively by the liver, the bone marrow and the lymph nodes.

CONTADO, NERIA

LADO, MARY LOUISSE

SEVERINO, MA. HARRIET

DE VEYRA, VERONICA

REGALA, NESTOR JR.

MEJARITO, GILBERT

NAT SCI 2

TTH 1:00-2:30