EKG day 2 - Cardiovascular System

Heart

Mediastinum: the space at the center of the chest that contains the heart and the great vessels

The heart itself is a two sided pump with 4 chambers. The receiving chambers are the right & left atria. The pumps are the right and left ventricles. The heart is made up of three layers. These layers are the epicardium (outer layer), myocardium (middle muscular layer), and endocardium (inner layer).

The heart itself is enveloped by a double layered sac, the pericardial sac, called the pericardium. The inner layer is called the visceral pericardium

valves- Ensure the flow of blood in one direction, prevent back flow

circulation- transporting blood throughout the body, depends on electrical activity of heart and ability to contract.

Heart sounds

The first heart sound (Lub)- is due to the closure of the atrioventricular valves.

The second heart sound (Dub)- is caused by the closure of the aortic & pulmonic semilumar valves

A third heart sound may be heard in athletes & children due to turbulence of blood flow

3 parts of circulation - pulmonary (deoxygenated bloods sent to lungs), systemic (fresh blood sent to organs) , coronary (supplies the heart with blood)

Sinoatrial node (S.A Node)- chief pacemaker. (60-100). Located in the right atrium.

ECG:

Limb lead- an ECG lead placed on an arm or leg

3 Bipolar lead- Type of ECG lead that measures the flow of electrical current in both directions at the same time

3 augmented leads (AVR, AVL, AVF) - normally small ECG lead tracing that are increased in size by the ECG machine in order to be interpreted

3 Unipolar (Precordial) (V1-V6) lead- type of ECG lead that measures the flow of electrical current in one direction only

precoridal lead- a type of lead placed on the chest in front of the heart, known as a V lead.

Einthovens triangel: