Physical characteristics of the heart
Size of a fist
Weighs less than a pound
Enclosed in the mediastinum
2/3 is to the left of the sternum; 1/3 is to the right of the sternum
Point of the heart that rests on the diaphragm and is considered the point of the 'cone'; found at approximately the level of the 5th rib.
The posterosuperior part of the heart that points toward the right shoulder and lies beneath the second rib.
Meaning of PMI
Stands for 'Point of Maximal Intensity'
Definition of PMI
The area just under the left nipple and between the 5&6th ribs where the apex can be felt because it touches the chest wall.
Be able to label the following layers of the heart
Functions of the Pericardium
Protects and anchors the heart
Prevents overfilling of the heart with blood
Allows for the heart to work in a relatively friction-free environment
Inflammation of the pericardium.
Causes pain deep to the sternum.
Heart rubs against the pericardial sac creating a creaking sound.
The pericardial layers can begin to stick together causing inflammatory fluid to build up.
Means 'Heart plug'
Occurs when the layers of the pericardium start to stick together and inflammatory fluid builds up so much that it limits the pumping action of the heart.
Have to drain using a needle.
Name the three layers of the heart wall
Outer, fatty layer of the heart wall.
Middle layer of the heart wall that consists of thick bundles of cardiac muscle; layer that contracts
A thin, glistening sheet of endothelium that lines the heart chambers and helps make up the valves.
Number of chambers of the heart
Name the four chambers of the heart
Holding tanks for blood that make sure that there is always blood available for the atria to send to the ventricles.
Divides the ventricles
Divides the atria
What is the function of the atria?
Receive blood returning to the heart
What is the function of the ventricles?
Pump blood to the lungs and to the rest of the body.
Know the pathway blood, returning to the heart from the body systems, takes as it goes through the heart.
-->Deoxygenated blood enters the heart via the Superior & Inferior Vena Cava
--> into the Right Atrium and through the Tricuspid (AV) Valve into the Right Ventricle
--> blood is pumped through the Pulmonary (SL) Valve and into the Pulmonary Trunk to the Right and Left Pulmonary Arteries
--> blood then travels to the lungs to become oxygenated and then returns to the heart via the Right and Left Pulmonary Veins
--> into the Left Atrium and through the Mitral or Bicuspid (AV) Valve to the Left Ventricle
--> blood is then pumped through the Aortic (SL) Valve and into the Aorta which will distribute the oxygenated blood to the rest of the body and then the whole process starts again.
Function of the valves
To ensure that blood flows in only one direction and the prevent the backflow of blood.
Names of the AV (atrioventricular) Valves
Mitral or Bicuspid valve
"Heart strings"; white collagen cords attached to each AV flap which help to anchor muscles
Names of the SL (semilunar) Valves
Where does the superior vena cava return blood from?
Areas of the body superior to the diaphragm.
Where does the inferior vena cava return blood from?
Areas of the body inferior to the diaphragm.
Forces the heart to pump and repump the same blood because the valve does not close properly and blood backflows.
Valve flaps become stiff, often because of repeated bacterial infection of the endocardium. This forces the heart to contract more vigorously than normal.
Crushing chest pain caused by low levels of oxygen reaching the myocardium.
Heart attack or coronary; blockage of the coronary arteries caused by a thrombus or embolus leading to oxygen deprivation.
Congestive heart failure
A progressive decrease in the efficiency of the heart. Usually occurs because of a clogging of the coronary vessels with fatty buildup (artherosclerosis), persistent high blood pressure, or multiple myocardial infarcts - leads to repair with scar tissue and not good tissue.
Rapid heart rate (over 100 beats per minute)
Heart rate that is substantially slower than normal (less than 60 beats per minute)
Be able to label all the parts of the heart
Superior vena cava
Inferior vena cava
Right Pulmonary artery
Left Pulmonary artery
Right Pulmonary vein
Left Pulmonary vein
Mitral (or Bicuspid) valve
Name and describe the two phases of a heartbeat
Phase 1 - Systole - Occurs when the ventricles contract, closing the AV valves and opening the SL valves to pump blood into the two major vessels leaving the heart
Phase 2 - Diastole - Occurs when the ventricles relax, allowing the back pressure of the blood to close SL valves and open AV valves
How do you properly take someone's blood pressure?
Cuff is inflated to stop blood flow to the artery in the arm.
Air pressure in the cuff is slowly released.
The 1st sound heard means that the ventricles have pumped with enough pressure to overcome the pressure of the cuff; should be around 120.
Air is released from the cuff until no more sound is heard which means there is a steady blood flow; should be about 80.