Cardiovascular (The Heart) Flashcards
The Heart: Layers
- Pericardium
- Myocardium
- Endocardium
Pericardium
- Fibrous Pericardium: tough, loose-fitting sac
- Serous pericardium: Parietal layer inside fibrous pericardium
- Pericardial space: bw. visceral and parietal layers - provides protection against friction
Myocardium
Thick, contractile middle layer; compressed heart cavities and blood
Endocardium
Delicate inner layer of endothelial tissue; protects myocardium from contact with blood
Chambers of the Heart
Right Atrium, Right Ventricle, Left Atrium, Left Ventricle
Atria (Atrium)
Not very thick; little pressure needed to move blood short distances
Auricle
Earlike flap protruding from each atrium increasing volume of blood that the atria can contain
Ventricles
Thicker; great force needed to pump blood further
Left ventricle wall thicker than right; pushes blood farther
Flow of Blood Through the Heart
LA - LV - systemic circ - RA - RV - pulmonary circ.
Atria: Blood Flow
“Receiving chambers”, receive blood from veins
Ventricles: Blood Flow
“pumping chambers”, push blood into large network of vessels
Valves of the Heart
- Open: when pressure in the first compartment is higher than that of the second
Close: when pressure in the second compartment is higher than that of the first; prevent blood from moving backwards
Atrioventricular (AV) Valve: Location
bw. atria and ventricles
Semilunar (SV) Valves: Location
bw. ventricles and great vessels
Atrioventricular Valves
- Tricuspid Valve (Right AV valve)
- Bicuspid (mitral) valve
Semilunar (SL) Valves
- Aortic Valve
- Pulmonary Valve
Tricuspid Valve
Bw. RA and RV
Bicuspid Valve
bw. LA and LV
Aortic Valve
Entrance to aorta
Pulmonary Valve
Entrance to pulmonary artery
Cardiac Muscles: Name them.
- Trabeculae Carneae
- Chordae Tendinae
- Papillary Muscle
Trabeculae Carneae
- Beamlike projections of myocardial tissue
- Help add force to inward contraction of the heart
Choarae Tendinae
- Tendinous cord which anchors papillary muscles to cusps of AV valves
- Hold AV valves shut
Papillary Muscle
- Muscles attached to cusps of AV vales
- Located in both ventricles
- When ventricles contract, pap. muscles also contract, pulling cusps together; stops backflow of blood into atria
Conduction System of Heart
Sinoatrial (SA) node (pacemaker)
Atrioventricular (AV) node
AV bundle
Purkinje Fibers
Sinoatrial (SA) Node
- Initiates heartbeat; sets pace
Atrioventricular (AV) Node
- Action potential comes form right atrium and relayed into AV bundle into ventricles
AV bundle & purkinje fibers
conduct impulses throughout muscles of both ventricles, stimulating them to contract
ECG
Record of hearts electrical activity
Events shown by an ECG
P Wave: depolarization of atria
QRS complex: depolarization of ventricles and repolarization of atria
T wave: repolarization of ventricles
Cardiac Cycle: consists of what?
Contraction (systole), relaxation (diastole)
Atrial Contraction (systole)
Starts: when atria contracts
Ends: Ventricles contract
- Atria are contracting
- Ventricular pressure increases
- AV valves open when pressure becomes greater
- SL valves remain closed
- Blood moves from atria to relaxed ventricles
Isovolumetric Ventricular Contraction (systole)
Starts: ventricles contract
Ends: Ventricular pressure higher than aortic pressure
- Volume remains constant, pressure increases rapidly
- Atria relaxes
- AV valves close
- SL valves remain closed
- First heart sound due to AV valves closing
