Pump, Pump, Pump it up!

Introduction: Welcome to the MOST important part of the circulatory system, THE HEART. As you first enter this section, there is a labeled heart picture. It labels the different parts. This picture was obtained from http://www.know-heart-diseases.com. In this section, you will find information about the parts of the heart, the control of a heartbeat, pulse, and the regulation of blood flow.

Parts of Heart

*These definitions are coming from the Mader textbook, pages 88 through 89.*

Heart: Cone-shaped, muscular organ located in the thoracic cavity whose rhythmic contractions maintain blood circulation.

Pericardium: Thick, membranous sac that that supports and protects the heart.

Atria: Atrium singular, upper chambers of the heart that receives blood.

Ventricles: Lower chambers of the heart.

There are, of course and as depicted above, many more parts of the heart. These are some basic parts described in the book.

Control Freak

"Each heartbeat is called a cardiac cycle" (Pg 90). The first paragraph on page 90 does a great job explaining the cardiac cycle. Further down the page, you'll find information about a heart murmur. I found this very interesting because I developed a heart murmur later on in life (most are born with it and it goes away.) So I had to go get an ultrasound performed on my heart. We found out that a valve of my heart was smaller than it should be, which was probably the cause. I never knew how or why I could have developed a heart murmur, but they told me if it did not go away, I would have to have surgery. It was nice to read in the book, years later, why the surgery would have been necessary.

There is nternal and external control of the heartbeat. Internal control, as explained on page 90, is due to Nodial tissue, "which has both muscular and nervous characteristics" (Pg 90). The SA node initiates the heartbeat, acting as a pacemaker to keep it regular. The medulla oblongata is the external control by means of parasympathetic and sympathetic parts of the nervous system.

Pulse

I really enjoyed the link provided on how to take a pulse. I am putting it here for easy reference. www.tutorials.com/09/0902/0902.asp
This picture was taken from www.nlm.nih.gov.

REMEMBER!!!! NEVER USE YOUR THUMB WHEN TAKING A PULSE! Your thumb has its own pulse. Some people will put their two fingers on the wrist, but then grasp the underside with their thumb. This is INCORRECT.

As the book indicates on page 92, "Pulse Rate Equals Heart Rate"

Being Regular

I really feel the book did a great job in the sections concerning the heart. Here are some terms to know all from the Mader textbook on page 92.

Blood Pressure: Pressure of blood against the wall of a blood vessel.

Systolic Pressure: Highest arterial pressure that is reached during ejection of blood from the heart.

Diastolic Pressure: Lowest arterial pressure occurs while the heart ventricles are relaxing.

Here is a picture that shows the cuff placed on the arm and which artery is being pinched shut momentarily. This comes from http://www.knowledgebase-script.com.

Conclusion: That concludes this section of the heart. We had a brief look at different parts of the heart, pulse, blood pressure, and keeping the heartbeat regular. Now we are going to move onto the first lab. This project involved discussing hypertension, taking blood pressures, and using the scientific method.