Grade 9 First Grading

1. CARDIOVASCULAR
SYSTEM
Parts and Functions

3. Circulatory System
is made up of blood vessels that carry
blood away from and towards the heart.
It is an organ that permits the blood to
circulate and transport oxygen, nutrients,
and hormones to cell, and removes waste
products, like carbon dioxide.

4. The Distinct Parts of the Circulatory System
 Coronary Circulation
- is the circulation of blood in the blood vessels that supply the
heart muscle (myocardium).
 Pulmonary Circulation
- Is the portion of the circulatory system which carries
deoxygenated blood away from the right ventricle, to the lungs,
and returns oxygenated blood to the left atrium and ventricle of
the heart.
 Systemic Circulation
- Provides the functional blood supply to all body tissue.
- It carries oxygenated blood from the left ventricle, through the
arteries, to the capillaries in the tissues of the body.

5. Heart – is a muscular pumping organ.
Blood – is the circulating medium.
Blood vessels – responsible for the delivery of oxygen and nutrients
to the tissue.
Composition of the Cardiovascular System

6. The Heart and its Chamber
 The heart is a muscular organ about the size of a
fist, located just behind and slightly left of the
breastbone. The heart pumps blood through the
network of arteries and veins called the
cardiovascular system.
 The heart has four chambers:
 The right atrium receives blood from the veins
and pumps it to the right ventricle.
 The right ventricle receives blood from the right
atrium and pumps it to the lungs, where it is
loaded with oxygen.
 The left atrium receives oxygenated blood from
the lungs and pumps it to the left ventricle.
 The left ventricle (the strongest chamber) pumps
oxygen-rich blood to the rest of the body. The left
ventricle’s vigorous contractions create our blood
pressure.
 Septa or septum a
muscular walls that
divides the heart into two
sides.

7. Pericardiumand The Layers of the Heart Wall
• Pericardium is the membrane that surrounds and protects
the heart.
• It composed of two layers the visceral layer or
epicardium (inner layer), parietal layer (outer layer).
Layers of the Heart
 Epicardium (external layer) is the thin, transparent outer
layer of the wall and is composed of delicate connective
tissue.
Myocardium (middle layer) comprised of cardiac muscle
tissue, makes up the majority of the cardiac wall and is
responsible for its pumping action.
Endocardium (inner layer) It provides a smooth lining for
the chambers of the heart and covers the valves.

8. Pericardiumand The Layers of the Heart Wall

9. The Heart Valves
There are four valves within the heart:
• The tricuspid valve is between the right atrium and
the right ventricle.
• The pulmonary valve is between the right ventricle
and the pulmonary artery.
• The mitral valve is between the left atrium and the
left ventricle.
• The aortic valve is located between the left ventricle
and the aorta.
• These valves open when blood passes through them
and then close to keep the blood from flowing in the
wrong direction.

11. Major Vessels of the Heart
The four chambers of the heart are attached to major veins or
arteries that either bring blood into or carry blood away from the
heart.
 Atria are the receiving stations of the heart. The right atrium
receives its supply of oxygen-poor blood from the two largest
veins in the body, the superior and inferior vena cava.
 The left atrium receives blood that has been oxygenated in the
lungs from the pulmonary veins. Both atria then pump their
supply of blood into the ventricles.
 Ventricles are the shipping stations of the heart. The right
ventricle pumps oxygen-poor blood into the lungs through the
pulmonary artery while the left ventricle pumps oxygenated
blood to the body through the aorta, the largest artery in the
body.

12. What is blood?

13. The Blood and Its Composition
 The blood which is the liquid tissue, is the medium of circulation. Its main
function is to transport materials and to fight infection.
 is a body fluid in humans and other animals that delivers necessary
substances such as nutrients and oxygen to the cells and transports
metabolic waste products away from those same cells.
 There are two compositions of the blood the plasma and corpuscles.
 Plasma the liquid portion of the blood.
 It comprises 55% of the blood by weight.
 Corpuscles are the formed elements of the blood.
 It comprises 45% of the blood by weight.

14. The Different Formed Elements
• Red Blood Cells (RCBs) or also known as erythrocytes the transporters,
transport gases, especially oxygen, to the all parts of the body. Structurally,
RBCs, are shaped like a biconcave disk without nucleus (a nucleated). The red
color is due to the pigment hemoglobin that enables them to carry and
transport oxygen.
• White blood cells (WBCs) or also known as leukocytes the disease fighters,
fight infection by secreting antibodies and engulfing foreign bodies
(phagocytes). Structurally, their shapes are irregular (amorphous) but they
are nucleated.
• Blood Platelets or also known as thrombocytes the blood clothing factors,
are cell fragments without nuclei that work with blood clotting chemicals at
the site of wounds.
• Plasma is the carrier, is the relatively clear, yellow tinted water, sugar, fat,
protein and salt solution which carries the red cells, white cells, and platelets.

15. Pulmonary Circulation

16. Blood Vessels
The blood vessels are part of the circulatory system and function to transport blood
throughout the body.
The Three Types of Blood Vessels
 Arteries are thick-walled to cope with the high pressure of the blood flowing through
it. Most of the arteries in the body transport oxygen-rich blood that moves away from
the heart. Starting from aorta, the artery branches into smaller arteries until they
become the smallest arteries called arterioles.
 Veins have thinner walls as compared to arteries. This is the reason why they easily
collapse when cut. Functionally, they convey blood coming from all parts of the body
back to the heart. Starting from the capillaries the smallest veins, called venules,
become larger until they become the largest vein called vena cava. The opening or
lumens of the veins are wider, that is why they are equipped with valves to prevent
blood from back flowing.
 Capillaries are the smallest blood vessels; they are just one-cell thick. This is the
reason why exchange of materials such as gases and nutrients can easily take place
between the blood and the cells. The capillaries are located between the arterioles and
venules.