1. Cardiovascular System
Biology 2122
Chapter 18

2. Heart Anatomy Location: Mediastinum Coverings (Pericardium)
Fibrous and Serous layers
Serous (Parietal and Visceral = epicardium)
Heart Wall (Layers)
Epicardium; Myocardium; Endocardium

3. Chambers Atria Ventricles Circulation Pectinate muscles; auricles
Superior and Inferior Vena Cava
Right-side
Deoxygenated Blood
Coronary sinus/Pulmonary veins
Ventricles
Trabeculae carneae/Papillary muscles
Pulmonary Trunk
Aorta
Circulation
Pulmonary vs. Systemic

5. Coronary Circulation Arterial – Left Coronary Artery
Anterior Interventricular
“Left Anterior Descending”
Circumflex
Arterial – Right Coronary Artery
Marginal artery
Posterior Interventricular artery
Venous
Cardiac veins
Coronary sinus
Great, middle, small cardiac veins
Angina pectoris and Myocardial Infarctions

6. Heart Valves Atrioventricular Valves Semilunar Valves Stenosis
Prevents backflow – chordae tendineae
Tricuspid (right)
Mitral (left)
Semilunar Valves
Aortic
Semilunar
Stenosis
Heart Animation

7. Microscopic - Cardiac Tissue Histology
Striated
Branching
Uninucleated
Intercalated discs
Gap junctions
Functional Syncytium
High in mitochondria

8. Cardiac Tissue - Contraction
Autorhythmic Cells
Heart Contracts as a unit
Ion passage through gap junctions
Steady and rhythmical waves of depolarization
Depolarization
Longer absolute refractory periods
250 ms
Similar to depolarization events in skeletal muscle
Differs in Ca++ release (SR)

9. Intrinsic Conduction System
Sets basic or normal rhythm
Autorhythmic Cells
Sequence of Excitation
SA node (right atria)
“pacemaker”
Atrioventricular node
Above tricuspid valve
Atrioventrical bundle
“bundle of his”
Superior interventricular septum
Bundle branches
Purkinje fibers
Apex
Intrinsic Conduction System Animation

10. Disorders
1. Arrhythmias 2. Fibrillation 3. Heart Block

11. Extrinsic Innervation and Control
Autonomic Nervous System
Sympathetic Effects
Parasympathetic Effects
Cardiac centers
Medulla Oblongata
Cardioacceleratory Center
Sympathetic (T1-T5)
Innervate SA and AV nodes
Cardioinhibitory Center
Vagus Nerve
To SA and AV nodes

12. Electrocardiogram
EKG lead placements

13. Electrocardiography The Electrocardiogram (ECG) Waves P-Wave QRS
Depolarization (Atrial contraction)
SA node
QRS
Ventricular depolarization
Ventricular contraction
T-Wave
Ventricular repolarization

14. Electrocardiography
P-Q Interval
S-T Segment
Q-T Interval

15. Abnormal ECG Non-functional SA Node
Heart Block – Some P-waves not conducted through (see more P-waves)

16. Heart Sound “Lub-Dub” Lub Dub Heart Murmer AV valve closure
SL valves snap shut
Ventricular relaxation
Heart Murmer

17. Cardiac Cycle Systole vs diastole
The cardiac cycle involves all events associated with blood flow through the heart during one complete heartbeat
Ventricular filling: Mid-Late Diastole
EDV (end diastole volume)
Ventricular Systole
ESV (end systolic volume)
Isovolumetric Relaxation – Early diastole

18. Cardiac Cycle
Cardiac Cycle Animation

19. Cardiac Output
CO is defined as the amount of blood pumped out by each ventricle in one minute.
calculated as the product of stroke volume and rate
HR X SV = 5.25 L/min
Stroke volume - volume of blood pumped out by one ventricle with each beat
CO is variable
increases in response to special demands like exercise
The difference between resting CO and maximal CO is called cardiac reserve. In trained athletes it is 7 times that of normal (35 L/min)

20. Stroke Volume Regulation
SV is the difference between EDV (blood in ventricle during diastole) and ESV (blood in ventricle during systole)
Normal SV = 70 ml/beat
Depends on the following factors
Preload (Frank-Starling Law)
Contractility
Afterload

21. Regulation of Stroke Volume
Preload
Frank-Starling Law
Cardiac muscle cells stretched to optimal length before contraction
Contractility
Independent of stretch
Greater Ca++ influx
Increased leads to greater SV
Afterload
Back pressure on aortic and pulmonary valves
Overcome pressure for ventricles to be able to eject blood

22. Regulation of Heart Rate
Autonomic Nervous System
2. Chemical Regulation
Hormones (Epinephrine and Thyroxine)
Ions
Calcium (Hypo- and Hypercalcemia)
Potassium (Hypo- and Hyperkalemia)
Disorders/Imbalances
Tachycardia and Bradycardia
2. Congestive Heart failure