CIRCULATORY SYSTEM

Learning Objectives:

Label a diagram of the heart and blood vessels.

Explain how the blood circulates through the heart to the body.

Identify two common disorders of the circulatory system.

Describe the function of RBC and WBC

Explain the electrical pathway of the heart.

The circulatory system is made of

1. Blood

2. Blood Vessels

3. Heart

1. Blood

- fluid that flows to all parts of the body to:

nourish the cells with - food substances and oxygen (O2)

to carry away waste products such as – carbon dioxide (CO2) and dead cells.

Blood Components:

1. Plasma – the liquid portion of blood without its cellular elements

2. Red Blood Cells (RBC) or erythrocytes - carry oxygen.

Blood Components:

3. White Blood Cells (WBC) or leukocytes - fight infection

4. Platelets (thrombocytes) – cause the blood to clot, which prevents excess bleeding.

Blood Types…

Type A + Type B + Type AB + Type O+ Type A - Type B- Type O - Type AB -

Human Blood Type: A, B, AB, or O

Blood Types

2. Blood Vessels

Organic conduits carrying blood to the heart and organs.

1. Arteries 2. Veins 3. Capillaries

Arteries and Veins

ARTERIES

Are thick elastic-walled tubes that carry oxygen filled blood away from the heart and lungs.

** with the exception of the Pulmonary artery which carries unoxygenated blood

VEINS

are thin walled vessels that carry unoxygenated blood back to the heart.

** with the exception of the Pulmonary vein** - takes oxygenated blood back to the heart

Capillaries

Are tiny channels that connect arteries and veins.

They have very thin walls that allow nutrients, oxygen and carbon dioxide to move in and out of the blood.

3. The Heart

Is the main organ of the circulatory system

The heart is approximately the size of your fist

The Heart

The outside of the heart is primarily muscle

Layers of the heart…

1. Pericardium – is a double membrane that lines the outside of the heart.

2. Myocardium – thickest layer and is made of muscle.

3. Endocardium- is the smooth inside lining of the heart.

http://mtsu32.mtsu.edu:11259/heartlayers2.jpg

Inside of the heart…

The septum is a segment of tissue that divides the heart cavity into the right heart and left heart

The heart is divided into 4 parts: The upper chambers are the atrium The lower chambers are the ventricles.

The beat goes on …and on…

How does the heart work?

The heartbeat begins in the heart:

The myocardium contracts rhythmically to perform its job as a forceful pump.

How the heart muscle contracts is controlled by a group of conducting cells.

Sinoatrial Node (SA) …Pacemaker of the Heart

Is located in the upper right atrium.SA node sends out an electrical impulse

that begins and regulates the heart.

It causes both Right and Left Atrium to contract.

The ventricles are relaxed at this time

Let’s take a look….

Sinoatrial Node (SA node)

The Atrioventricular Node (AV node)

The impulse reaches the AV node which is located between the right atrium and right ventricle.

The electrical impulse is carried to the conducting fibers in the septum.

These are called the Bundle of His

Where is the AV node and the Bundle of His?

Purkinje Fibers

The Bundle of His continues to divide into Right and Left branches and then into a fine network of branches spreading throughout the Purkinje network.

When the impulse reaches the Purkinje fibers it causes the ventricles to contract.

This cycle completes one heart beat! Each cycle takes 0.8 seconds!

Purkinje Fibers

How does the blood flow through the heart?

Superior and Inferior Vena Cava which are the largest veins which bring unoxygenated blood to the right atrium from all parts of the body.

Find both Superior and Inferior Vena Cava on the picture.

From the right atrium the blood passes through the tricuspid valve into the right ventricle.

This valve is located between the right atrium and right ventricle.

It closes when the ventricle pumps blood out of the heart.

Find where the tricuspid valve would be located .

The right ventricle pumps the blood through the pulmonary semi-lunar valves. It allows blood to travel from the right ventricle into the pulmonary artery and then to the lungs.

Find the ® ventricle and pulmonary artery

O2 and CO2 exchange in the lungs. Here is where the blood gets rid of the CO2 and picks up O2.

The O2 rich blood flow from the lungs to the pulmonary veins into the left atrium.

Find the pulmonary veins and left atrium.

The left atrium receives oxygenated blood and pumps it through the mitral valve into the left ventricle.

The left ventricle pumps blood into the aorta which delivers the oxygenated blood throughout the whole body.

Find left atrium, mitral valve, left ventricle and aorta on the picture.

Quick Review Time….

Three parts of the circulatory system are:

1. Blood 2. Blood vessels:

Arteries, veins & capillaries

3. Heart

The type of blood vessels that carry O2 back to the body are called……

Arteries

The exception? Pulmonary artery

Besides O2 what else does blood provide to the body?

Nutrients

The node that is called the pacemaker of the heart is called….

Sinoatrial Node (SA node)

The bottom chambers of the heart are called…

Ventricles

Label the heart

Circulatory Unit …continues…

Common Disorders of the Circulatory System

Arteriosclerosis-is present when the walls of the arteries become thick and harden. Less blood is able to flow through the arteries because the opening is small.

Common Disorders of the Circulatory System

Atherosclerosis-is the fatty material or plaques that deposit in the walls of the arteries.

The presence of atherosclerosis causes hardening of the arteries; other wise known as …..

ARTERIOSCLEROSIS

Disorders

Aneurysm –is a weakened section

in the wall of a blood vessel. Aneurysms are often found on the aorta. An aortic aneurysm that ruptures usually causes immediate death.

Angina Pectoris –chest pain resulting from insufficient blood flow to the heart muscle.

Myocardial Infarction (MI) or heart attack –Occurs when the coronary arteries of the heart are blocked. This blockage can be due to atherosclerosis..

which is the plaque that builds up inside the blood vessels.

Endocarditis – inflammation of the inner lining of the heart.

Disorders…

Congestive heart failure-the heart is unable to pump enough blood.

Cerebral Vascular Accident (CVA) –a stroke caused by blockage or rupturing of arteries in the brain.

http://www.adaweb.net/Portals/0/Coroner/images/ischemic_stroke.jpg

WITH A STROKE, TIME LOST IS BRAIN LOST

Heart Murmur –is a sound that indicates a faulty heart valve that does not close completely, allowing blood to flow back and forth between the chambers.

http://distractible.org/wp-content/uploads/2008/08/350px-diagram-of-the-human-heart-croppedsvg-thumb.png

Disorders …

Anemia –decrease in the quantity and quality of RBC.

Leukemia –Cancer of the blood & bone marrow, particularly the white blood cells (WBC).

Terminology – what does it mean?

Bradycardia –

abnormally slow heart rate.

Cardiopulmonary – pertaining to the heart and lungs.

Cardioscope – instrument used to examine the inside of the heart.

Cardiovascular – pertaining to the heart and blood vessels.

Cyanosis – abnormal blue skin color due to poor circulation or lack of oxygen.

Endocarditis – inflammation of the inside layer of the heart

Hemostasis – stoppage of blood flow

Hypertension – high blood pressure