Heart
 2 types of circuit – pulmonary circuit and systemic circuit
 3 types of vessels – Arteries, veins, and capillaries
 4 chambers of the heart – right and left atrium, right and left ventricle
Atria on top and ventricles on bottom
 Wall of the heart – deepest part is called endocardium - Simple Squamous
 Myocardium – Dense tissue
 Layer inside heart is called visceral layer and part outside of the heart are
called parietal layer.
 Pericarditis – caused by pathogens in pericardium
 Inflamed pericardial surfaces rub against each other causing cardiac
tamponade.
 Cardiac skeleton – 4 dense bands of elastic tissue – helps to not make the
blood flow back.
 interatrial Septum separates 2 atriums interventricular septum separates
2 ventricles
 Atrioventricular valves – Tricuspid and mitral valves – prevent backflow.
 Semilunar Valves – pulmonary valves go to lungs. (pulmon = lungs),
Aortic valves goes to aorta and to the body.
 Superior vena cava – carries blood from the top part of the body
 Inferior Vena cava – carries blood from the bottom part of the body
 Right atrium - Foramen Ovale – huge hole that transfers blood, connects
the two atria of fetal heart.
 Fossa Ovalis – closes after brith

Tricuspid valves got 3 cups – prevent the backflow
 Mitral Valve got 2 cusps.
 Chordae Tendineae – Thread like bands of connective tissue
 Saclike expansions called aortic sinuses hold the extra blood that flows
back in aorta
 Coronary artery disease CAD - partial or complete blockage of coronary
artery
 Angina Pectoris – called chest pain – individual may feel uncomfortable at
rest – symptom of CAD.
results in myocardial infraction also called heart attack
Heartbeat
 A single cardia contraction
 Pacemaker cells – auto rhythmic
 Nervous system doesn’t play a single role.
 Beating of the SA node is going to develop your sinus rhythm.
 SA node – 60 -100 action potential per minute – sets the heartbeat – opening
K+ channels
 AV node – 40 – 60 action potential per minute
 SA nodes are the main pacemaker
 Pacemaker cells controls steps 1-3
 Conducting cells controls steps 4 and 5
 Impulse is delayed for 100 msec at AV node
 Strong ventricular contraction would close AV valve
 Purkinje fibers (Conducting fibers) distributes impulses to ventricular
myocardium.
 Bradycardia – low heart rate – conduction deficit
 Tachycardia – faster heart rate – conduction deficit
 Ectopic pacemaker – an electrical signal note generated not where it should
be. It messes up the timing of heart contraction rhythm.
 Premature atrial contraction –
 Paroxysmal Atrial Contraction –
 Ventricular Fibrillation –
 Desmosomes and gap junctions hold the cells together.
 Fast channels peak up sodium channel fast
 The plateau phase takes the calcium channels slow all the way down.
 Slow potassium channels lower everything down.
 Refractory period – nothing happens at this point – maintains heart rhythm
 Aerobic energy provides energy for contraction
 Normal heat beat rate – 75 beats per min
Frank – Starling Principle
 As EDV increases, stroke volume increases
