The cardiovascular system consists of the heart and blood vessels, and has three main functions: 1. Circulate oxygenated blood to tissues and organs via the circulatory system 2. Transport nutrients to and remove waste from all body cells 3. Maintain homeostasis in the body through regulated blood flow The three main components are the heart, blood, and blood vessels. The heart pumps blood through a closed system of arteries, veins, and capillaries to provide cells with oxygen and nutrients while removing carbon dioxide and other wastes.

1. CARDIOVASCULAR SYSTEM
OBJECTIVES
 Define the Cardiovascular System
 Functions of Cardiovascular System
 Identify the major parts of cardiovascular system
 Discuss the major parts of cardiovascular system and its functions
 Importance of Cardiovascular System
INTRODUCTION
The term Cardiovascular is a combination of two words; “Cardio” and “vascular”.
The term “cardio” is derived from “cardiac” meaning HEART and the term “vascular” means BLOOD VESSELS.
The cardiovascular system is sometimes called the blood-vascular, or simply the Circulatory System. It consists
of the heart, which is a muscular pumping device, and a closed system of vessels called arteries, veins, and
capillaries. As the name implies, blood contained in the circulatory system is pumped by the heart around a
closed circle or circuit of vessels as it passes again and again through the various "circulations" of the body.
FUNCTION OF CARDIOVASCULAR SYSTEM
The cardiovascular system is the transport system of the body, responsible for circulating oxygen and
transporting nutrients throughout the body. In addition to providing oxygen and nutrients, blood also helps
cleanse the body by collecting waste products like carbon dioxide. The continuous, controlled circulation of the
blood the cardiovascular system provides is what maintains homeostasis. With oxygen provided and waste
removed, the body can perform its normal functions.
 Circulates OXYGEN and removes Carbon Dioxide.
 Provides cells with NUTRIENTS.
 Removes the waste products of metabolism to the excretory organs for disposal.
 Protects the body against disease and infection.
 Clotting stops bleeding after injury.
 Transports HORMONES to target cells and organs.
 Helps regulate body temperature.

2. PARTS OF CARDIOVASCULAR SYSTEM
While there are numerous mechanisms and processes that help regulate and promote the circulation of blood,
there are three main parts of the cardiovascular system.
1. Blood
Blood is the fluid that carries the oxygen and nutrients vital to
the function of the body, as well as the waste that needs to be
removed. Without blood, the human body could not function.
Blood flows between the heart and the rest of the body, with
red blood cells providing oxygen and white blood cells fighting
foreign invaders. In the cycle of blood flow, the lungs provide
the oxygen that the blood delivers to the rest of the body.
Blood has four main components:
plasma, red blood cells, white blood cells, and platelets.
The liquid part, called plasma, is made of water, salts, and protein. Over half of your blood is plasma.
The solid part of your blood contains red blood cells, white blood cells, and platelets. Red blood cells (RBC)
deliver oxygen from your lungs to your tissues and organs.
A blood type is a classification of blood, based on the presence and absence of antibodies and inherited antigenic
substances on the surface of red blood cells. These antigens may be proteins, carbohydrates, glycoproteins, or
glycolipids, depending on the blood group system. In addition to the A and B antigens, there is a protein called
the Rh factor, which can be either present (+) or absent (–), creating the 8 most common blood types (A+, A-,
B+, B-, O+, O-, AB+, AB-).
2. Blood Vessels
Another essential part of the cardiovascular system is the blood vessels, which are tubes that transport blood
throughout the body. Blood vessels are the channels or conduits through which blood is distributed to body
tissues.
-Over 60,000 Miles of blood vessels throughout the body
The Three Major Types of Blood Vessels: Arteries, Veins, and Capillaries
1. Arteries — transport blood away from the heart.
Types of Arteries:
Elastic arteries -also called conducting arteries or conduit
arteries. They have a thick middle layer so they can stretch in
response to each pulse of the heart.
Muscular (distributing) arteries - Are medium-sized. They draw
blood from elastic arteries and branch into resistance vessels.
These vessels include small arteries and arterioles.
Arterioles -Are the smallest division of arteries that transport
blood away from the heart. They direct blood into the capillary
networks.

3. 2. Veins — return blood back toward the heart.
Types of Veins:
Deep veins- are located within muscle tissue. They have a corresponding artery nearby.
Superficial veins -are closer to the skin’s surface. They don’t have corresponding arteries.
Pulmonary veins -transport blood that’s been filled with oxygen by the lungs to the heart.
3. Capillaries — surround body cells and tissues to deliver and absorb oxygen, nutrients, and other
substances.
— are the smallest and most numerous of the blood vessels. They connect between the arteries (which
carry blood away from the heart) and the veins (which return blood to the heart). The primary function
of capillaries is the exchanging of materials, like oxygen, between the blood and tissue cells.
 The capillaries also connect the branches of arteries and to the branches of veins.
The Blood Vessel Wall has Three Layers
The walls of most blood vessels have three distinct layers: the tunica externa, the tunica media, and the tunica
intima. These layers surround the lumen.
1. Tunica externa (tunica adventitia)— The outermost
layer of a blood vessel. Its mostly composed of Collagen
and Elastic Fiber
2. Tunica media — The middle layer of a blood vessel. It
is primarily smooth muscle and is usually the thickest
layer. Thickest layer in arteries. Thinner layer in veins.
Made up of smooth muscle and elastic fiber
3. Tunica intima (tunica interna)— The innermost layer of
a blood vessel. Made up of elastic fiber and collagen.
Also It's consistency varies based on the type of blood
vessels.
 Lumen — The hollow interior through which blood flows.
There Are Two Types of Circulation: Pulmonary Circulation and Systemic Circulation
 Pulmonary circulation — moves blood between the heart and the
lungs. It transports deoxygenated blood to the lungs to absorb
oxygen and release carbon dioxide. The oxygenated blood then
flows back to the heart.
 Systemic circulation — moves blood between the heart and the
rest of the body. It sends oxygenated blood out to cells and
returns deoxygenated blood to the heart.

4. 3. Heart
The heart is a muscular pump that provides the force necessary to circulate the blood to all the tissues in the
body. Its function is vital because, to survive, the tissues need a continuous supply of oxygen and nutrients, and
metabolic waste products have to be removed.
Functions of the heart
 Pumping blood around the body supplying oxygen and nutrients to cells and removing carbon dioxide
and other waste
 Sending deoxygenated blood to the lungs to be oxygenated
 Sending oxygenated blood to whole body
 Prevent mixing of oxygenated and deoxygenated blood by its septum
 Prevent back flow of blood by its valves
Layers of the Heart Wall
Three layers of tissue form the heart wall.
1. The outer layer of the heart wall is the epicardium —
contains blood vessels
2. The middle layer is the myocardium — composed of
contractile tissues
3. The inner layer is the endocardium — composes the
values, inner lining of the chambers, and contains vessels
and nerves
The internal cavity of the heart is divided into four chambers:
1. Right atrium — receives oxygen-poor blood from the body
and pumps it to the right ventricle.
2. Right ventricle — pumps the oxygen-poor blood to the lungs.
3. Left atrium — receives oxygen-rich blood from the lungs and
pumps it to the left ventricle.
4. Left ventricle — pumps the oxygen-rich blood to the body. It
is the largest and strongest chamber in your heart.
Walls of Heart Chambers

5. 2 Types of Heart Valves
Atrioventricular valves (Mitral valve and Tricuspid valve) — prevent blood flow from ventricles to atria
Semilunar valves (Aortic valve and Pulmonary valve) — prevent blood flow from arteries to ventricles
The 4 heart valves
The Heart Valves
Four valves regulate blood flow through your heart:
1. Tricuspid valve — regulates blood flow between the
right atrium and right ventricle.
2. Pulmonary valve — controls blood flow from the
right ventricle into the pulmonary arteries, which
carry blood to your lungs to pick up oxygen.
3. Mitral valve — lets oxygen-rich blood from your
lungs pass from the left atrium into the left ventricle.
4. Aortic valve — opens the way for oxygen-rich blood
to pass from the left ventricle into the aorta, your
body’s largest artery.
 Pulmonary veins — carry oxygen-rich blood from
your lungs to your heart.
 Pulmonary arteries — carry oxygen-poor blood
from your heart to your lungs.
 Aorta — is the main vessel through which oxygen-
rich blood travels from the heart to the rest of the
body.
 Inferior vena cava —the body’s largest vein, carries oxygen-depleted blood back to your heart from the
lower part of your body.
 Superior vena cava — the second biggest vein, brings oxygen-poor blood from your upper body to your
heart.

6. Importance of Cardiovascular System
The cardiovascular system, are important because they bring oxygen, nutrients and other good things to every
cell in your body. They also take away carbon dioxide and waste. This supply of nutrients and the removal of
waste is the main function of the cardiovascular system.