The Circulatory SystemLet’s get pumped!

Presented by:Tina Livingston RN,CRNI,OCN

The Heart…..a muscular organ, the center of emotions,or a suit in a deck of cards?

Let’s take a closer look at this magnificent system

The Discovery of the Human Circulatory System

The earliest known writings about the circulatory system can be found in the Ebers Papyrus (16th century BCE) **Papyrus is an ancient writing material made from a plant in Egypt** Even then it was attributed to not just a physical but a spiritual and emotional aspect of humanity.

Though the circulatory system was written about and contemplated about throughout history it was still not understood.

Separate and distinct parts of the system would be identified but not understood on how each part functioned.

Most early Greek physicians believed that arteries delivered only air and nothing else.

A Greek physician, Herophilus (335-280 BCE)discovered a clear difference in veins and arteries through dissection of dead corpses

It was 500 years later that Galunus (AD 129 200/217) concluded that the venous system carried blood that held nutrition and the arterial system carried “body heat”

Enter: Dr. William Harvey, an English physician, named the “Father of Cardiovascular Medicine”

In 1628 he published his findings in the role of the heart and circulation of blood in a closed system. He felt his studies were complete.

Thirty years later it would take an Italian physician, Malpighi, to identify the capillary system that connects arteries to veins.

“While anatomically, the circulatory system had finally been mapped, true understanding of it’s function would not be achieved until the 20th century” (2002-2012 Helium, Inc.)

“Even as late as the early 1900’s physicians were still prescribing bloodletting and leech therapy” (2002-2012 Helium, Inc.)

The Anatomy of the Heart

The heart is the size of your fist and lies usually on the left side of the chest.

It is protected by the sternum, the spine, and the rib cage.It has 4 chambers, the right atrium, the right ventricle,

the left atrium and the left ventricle. (the heart of a pig is the same with 4 chambers)

The normal heartbeat for an adult is 60-100 beats per minute.

The heart is encased in a sac known as the “pericardial sac” this sac protects the heart from infection and trauma, anchors the heart and protects it from friction while pumping.

The heart chambers are separated by four valves and help keep blood from flowing backwards in the heart.

The valves between the atria and ventricles are the tricuspid valve (right) and the mitral valve (left)

The valves which connect the ventricles out to the body are the Pulmonary valve (to the lungs) and the Aortic valve (to the body)

Let’s see it in action!.....

Blood Flow in the HeartEach of the four chambers have specific jobs in

blood flow.The atria receives blood into the heart and the

ventricles pump blood out of the heart.The right side of the heart moves de-oxygenated

blood to the lungsThe left side of the heart moves oxygenated blood

out to the body.The amount of blood pumped out of the heart per

minute is referred to as “cardiac output”. Normal cardiac output for an adult is 4-8 liters per min.

Let’s look at it in 3D

The rest of the system: Vasculature

The circulatory system is comprised of the heart and the vascular system.

The vascular system is comprised of 5 different vessels, arteries, arterioles, veins, venuoles, and capillaries.

Arteries carry blood away from the heart.Veins carry blood towards the heart.Capillaries are responsible for the joining of

the 2 and the delivery of oxygen to the tissues and the removal of carbon dioxide.

Arteries are muscular and can contract to accommodate changes in blood flow and pressures

Arteries produce pulses. Let’s see what pulses we can find…

Find these pulses:CarotidRadial

Post tibialPopliteal

Ulnar

Arteries connect to arterioles which connect to the capillaries.

Capillaries then connect to venuoles which connect to the veins thus completing the closed system.

Veins are not muscular, they cannot change size due to pressure or blood flow and do not have a pulse.

Veins contain valves which help to prevent back flow of blood in the system.

The Great VesselsThe “Great Vessels” are the major vessels in the

body, they consist of arteries and veins.The largest artery in the body (this is often a

crossword clue) is the Aorta.The Aorta is divided into different sections, the

ascending aorta, the aortic arch, the descending aorta and the descending abdominal aorta.

The coronary vessels (arteries around the heart) are fed first before the ascending aorta or the arch.

The aortic arch feeds the brain via the carotid arteries (hence where a pulse is checked when giving CPR to an adult)

The Pulmonary artery is another “great vessel”, which is responsible for carrying de-oxygenated blood from the right ventricle to the lungs where carbon dioxide is exchanged for oxygen. (interestingly enough, this is the only artery that carries de-oxygenated blood)

The oxygenated blood is returned to the left atrium through the pulmonary veins (these are the only veins in the body that carry oxygenated blood)

TIP: Arteries always carry blood “away” from the heart and Veins always carry blood “toward” the heart

The venous system also has “great vessels”. The Inferior and Superior Vena Cava are the great veins that return deoxygenated blood from the tissues to the heart.

Let’s take another 3D look…

The Conductor :How does the Heart know when to pump?

The heart is regulated by an electrical conduction system.

A bundle of highly sensitive nerve endings in various areas of the heart stimulate the heart to pump at specific rates

A diagnostic tool used to monitor the electrical activity in the heart is called an Electrocardiogram (EKG)

•The Sinus Node (SA Node) regulates a normal heart rate 60-100. It stimulates the atrium to contract and empty all the blood from it.•The Atrioventricular Node (AV Node) takes over if the SA node fails, it regulates the heart rate at 40-60, this usually means the atrium may not have emptied completely.•Lastly, (the sign of a dying heart) if both the above nodes fail, the ventricles will beat at 20-40 via the purkinje fibers

Amazing!!!This is a life sized model

of the heart of a blue whale, the largest animal on Earth. A blue whale heart is the size of a small car and weighs around a ton. They only beat 8-10 times a minute, but pump an astonishing 2000 to 5000 liters through the whale's blood vessels.

Abnormalities of the HeartArrhythmiasHeart attackHeart failure

Arrhythmias(abnormal heart

rhythms)• Ventricular Fibrillation- the most common rhythm seen in cardiac arrest•Heart blocks- cause slower heart rates when the conduction system of the heart gets blocked.(i.e. SA node doesn’t fire so the AV node takes over.)Commonly results in patient getting a pacemaker.

Heart Attacks•Heart attacks are also called “MI”s or Myocardial Infarctions•Heart attacks or MI’s are caused from a blockage to the blood flow to the heart muscle. The coronary arteries are blocked by plaque or blood clots

Heart Failure•As people age, their heart muscle can weaken which makes it pump less efficiently.•Weakening heart muscle can result in blood pooling in the ventricles, this is known as heart failure.•Sometimes blood can pool enough to even back up into the lungs. Signs of heart failure can include heart murmurs, shortness of breath and even cool extremities causing lower oxygenation of tissues due to low blood flow.

Note to self: Always check for a pulse!

References Cardiac Cycle: By Regina Bailey, About.com Guide:

http://biology.about.com/od/anatomy/ss/cardiac_cycle.htm Blood Vessels: By Regina Bailey, About.com Guide:

http://biology.about.com/od/humananatomymybiology/ss/blood_vessels.htm The Heart and the Circulatory System, William Harvey-Father of

cardiovascular Medicine: By Regina Bailey, About.com Guide: http://biology.about.com/library/organs/blcircsystem2.htm

The history of discovery of the human circulatory system: by Theresa Cobb : Helium, Inc.: http://www.helium.com/items/1550920-circulatory-system-blood-veins-arteries-greek-itialian

Visible Body 3D Heart & Circulatory Premium 2: http://www.visiblebody.com

Far Side cartoon, by Gary Larson: http://www.thefarside.com