2. -CIRCULATORY SYSTEM-
-THE HEART-
-THE BLOOD-
-THE BLOOD VESSELS-
-THE BLOOD CIRCUIT-
-THE LYMPHATIC SYSTEM-

3. –
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 Human
2. The Blood
3. The Blood Vessels

4. 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.

6. 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.

7. 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.

8. 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.

9. CELL TYPE:
1. Red Blood Cells (Erythrocytes)-
Transport oxygen and a small amount of carbon
dioxide.

10. 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.

11. Eosinophil Basophil Neutrophil
Lymphocytes Monocyte

12. 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 .

13. Artery/Arteriole Vein / Venules
carries blood away from carries blood towards
the heart. the heart.
Artery Vein

14. 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.
Veins 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.

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

16. Pulmonary circuit Systemic circuit
Pulmonary circulation is the Systematic is the one that
half portion of the carries fully oxygenated
cardiovascular system which blood from the heart going to
carries oxygen -depleted the brain and body. The
blood away from the heart, to second order systemic output
the lungs , andreturns blood is selectively
oxygenated (oxygen-rich) deoxygenated by the needs of
blood back to the heart. the peripheral organs,
returning once again to the
heart .

17. BLOOD CIRCULATION

18. 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.
Components of lymphatic system:
1. Lymph Capillaries
2. Lymph Nodes

19. Lymph Capillaries
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.

20. Lymph Nodes
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.

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

22. 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 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.

23. 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.