Circulation

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The Circulatory System
2
Components of the Human Circulatory System

• The Heart
• Blood Vessels
• Blood
• Lymphatic Vessels
• Lymph

3
Functions of the Circulatory System

• Transport oxygen to cells
• Transport nutrients from the digestive system to
  body cells
• Transport hormones to body cells
• Transport waste from body cells to excretory
  organs
• Distribute body heat

4
Energy Requirements

• lots of mitochondria
• aerobic respiration

5

• Mechanisms and events of contractions
• All or none law- at organ level, not cellular
  level
• Means of stimulation- autorhythmicy
• Length of refractory period- cardiac (250ms),
  skeletal (1-2ms)

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Heart is located in the mediastinum
Location of Heart
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Circulation
Pulmonary Circuit
Systemic Circuit
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Pericardial Cavity
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Layers of Cardiac Tissue
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Layers of Cardiac Tissue

• Visceral pericardium
• Outer protective layer
• Myocardium
• Middle layer
• cardiac muscle tissue
• Endocardium
• Inner layer
• epithelial and connective tissue
• Lines all of the heart chambers and covers heart
  valves.
• Purkinje fibers.

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Heart Anatomy
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Heart Anatomy
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Heart Anatomy
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Heart Anatomy
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VALVES
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Contraction Cycle of the Heart
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Contraction Cycle of the Heart
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Contraction Cycle of the Heart
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Nerve Innervation
pons
Vegas nerve from medulla (parasympathetic
division) ? acetylcholine (slows heart)
Cardioacceleratory center in medulla
(sympathetic) ? adrenaline from adrenal glands
(speeds up heart)
medulla oblongata
vegas
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Excitation of the Heart
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Excitation of the Heart
Depolarization of the atria
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Excitation of the Heart
Depolarization of the ventricles
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Excitation of the Heart
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Excitation of the Heart
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Electrocardiogram (ECG)

• P atrial depolarization 0.1 sec atria
  contracts
• QRS ventricular depolarization ?ventricles
  contract (lub), contraction stimulated by Ca
  uptake
• T ventricular repolarization ? ventricles relax
  (dub)

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Heart Anatomy
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Inquiry

1. Name the 2 pacemakers of the heart.
2. What is the QRS wave?
3. What is the middle layer of heart tissue called?
4. What is the parietal pericardium?
5. Why is the left ventricle thicker walled than the
   right?
6. What blood vessel returns blood from the lungs to
   the heart?
7. What is the function of the chordae tendinae?
8. How does the heart avoid going into tetanus?
9. What function does serous fluid serve?