The Heart

1
The Heart

• Karen Kraus
• BIOL 204
• September 11, 2007

2
Why does my heart beat for you?

• Double pump
• Diastole
• Systole
• Size
• Positioning

3
Around the world

• Pericardium
• Fibrous
• Serous
• Parietal
• Visceral
• Myocardium
• Endocardium

4
Heart Shaped Box

• Atrium
• Ventricle
• Valve
• Atrioventricular
• Semilunar
• Venae cavae
• Pulmonary vessels
• Aorta

5
Short circuit

• Pulmonary circuit
• Systemic circuit
• Coronary circulation
• Angina pectoris
• Myocardial infarction

6
The root of it all

• Cardiac muscle
• Striated
• One or two nuclei
• Branching
• Intercalated disks
• Intrinsically stimulated
• Dually innervated
• Slow contraction speed
• More stretch more vigorous contraction
  (Frank-Starling Law)

7
Feel the rhythm

• Cardiac conduction system
• SA and AV nodes
• Bundle of His
• Purkinje fibers
• Gradual depolarization to -40mV
• Potassium and calcium channels

8
Follow the leader

• Pacemaker controls
• Voltage regulated sodium channels open
• Calcium channels open to prolong the refractory
  period
• In both cases, potassium leaving the cell
  repolarizes it

9
Versus

• Compared to skeletal muscle
• Intrinsically stimulated
• Myocardium contracts as a unit, doesnt have
  smaller motor units
• Refractory period is longer to prevent tetanus
  and allow diastole (filling of the chamber)

10
See the beat

• Electrocardiogram (electrokardiogram)
• P wave
• QRS complex
• T wave
• Extrasystole
• Arrythmia

11
Beating the cycle

• Cardiac cycle
• 0.8 seconds from one atrial systole to next
  atrial systole
• lub dub
• Stenosis and valve incontinence (murmur)

12
Turn up the volume

• Cardiac output stroke volume X heart rate
• Preload
• Contractility
• Afterload
• Regulation of HR
• Atrial reflex (Bainbridge reflex)
• Congestive heart failure

13
Abnormalities
14
Abnormalities
15
Neat stuff

• http//www.ekgreading.com
• http//mywebpages.comcast.net/wnor/thoraxlesson4.h
  tm
• http//www.visibleheart.com/videoclips.html