Notes for cardiovascular system

1. Chapter 15
Cardiovascular
System
THE HEART

3. LAYERS OF THE HEART
• Pericardium
• Outer layer; protects heart
• Pericardial fluid between pericardium and
epicardium reduces friction
• Epicardium
• Attached to the surface of the heart
• Myocardium
• Cardiac muscle fibers, involuntary, striated,
connected by intercalated discs
• Endocardium
• Squamous epithelium lines inside of myocardium
• Covers valves of heart and tendons

7. Chambers of the Heart
The human heart contains 4 chambers.
This varies in other animals. The number of chambers
directly relates to how efficient the oxygenation process
is.
The human heart is divided by the interatrial septum in
the atria and the interventricular septum in the
ventricles.
This ensures no blood mixing.

11. VALVES
• Atrioventricular (AV) lie between atria and
ventricles with blood pushed through by
pressure
• Tricuspid on right side
• Bicuspid (mitral) on left side
• Semilunar prevent blood from flowing back
into the heart so blood flows from ventricles to
arteries
• Pulmonary – between right ventricle and pulmonary
trunk
• Aortic – between left ventricle and aorta

15. Vocabulary
Words
4 layers of the heart
Heart chambers
Vena cava-superior and inferior
Coronary sinus
Pulmonary artery
aorta

16. BLOOD SUPPLY TO THE
HEART
• Coronary arteries
• Feed the myocardium
• Originate from ascending aorta
• Right feeds right side (largest)
• Left feeds left side
• Deoxygenated blood collects in coronary sinus

19. Conduction
•1% of heart cells generate action potential (ap)
–Pacemaker sets rhythm for heart
–Conducting system propagates action potentials
throughout the heart
1. Excitation at sinoatrial node (SA) to both atria
which contract
2.Also excites atrioventricular node (AV) where ap
slows for atria to empty

20. Conduction
3. Action potential enters AV bundle in ventricular
septum
4. To Purkinje fibers and ventricles contract
–The SA node generates action potentials 100 times
per minute, faster than any other region so this is the
pacemaker for the heart.

22. Vocabulary
Words
Tricuspid valve
Chordae tendineae
Papillary muscles
Bicuspid (mitral) valve
Pulmonary valve
Aortic valve

23. Electrocardiogram
P wave
-depolarization
-spreads from SA node
-contraction of atria

24. Electrocardiogram
QRS complex
-onset of ventricular
depolarization
-spreads through the
ventricles

25. Electrocardiogram
T wave
-ventricular repolarization
occurs before
ventricles relax

27. Cardiac Cycle
relaxation contraction relaxation

28. • Two atria contract while
ventricles relax and visa-versa
• Relaxation period
• all 4 chambers in diastole
• ventricle pressure drops and
AV valves open
• T wave
• Atrial systole (contraction)
• atria contract
• last of blood into ventricles
• P wave
• Ventricular systole
(contraction)
• contraction of ventricles
• AV valves close and Semilunar
valves open
• QRS complex

29. • Heart Sounds:
• Lubb – AV valves closing
• Dubb – SLV valves closing; short;
sharp sound

30. REGULATION OF HEART RATE
• Autonomic
• Originates in medulla
oblongata
• sympathetic
• conduction system, and
chambers
• parasympathetic
• vagus nerve
• neuro and
chemoreceptors
• Chemical
• hormones: epinephrine
and norepinephrine
• ions: Na+
, K+
, Ca2+

32. Vocabulary
Words
Sinoatrial node (SA)
Atrioventricular node (AV)
Atrioventricular bundle
(Bundle of His)
Purkinje fibers
EKG or ECG
Diastole
Systole