the heart
DESCRIPTION
The Heart. The Location of the Heart in the Thoracic Cavity. Figure 20.2c. The pericardia. Echocardiogram. The cardiovascular system is divided into two circuits. Pulmonary circuit blood to and from the lungs System circuit blood to and from the rest of the body - PowerPoint PPT PresentationTRANSCRIPT
The Heart
The Location of the Heart in the Thoracic Cavity
Figure 20.2c
The pericardia
Echocardiogram
The cardiovascular system is divided into two circuits Pulmonary circuit
blood to and from the lungs System circuit
blood to and from the rest of the body
Vessels carry the blood through the circuits Arteries carry blood away from the
heart Veins carry blood to the heart Capillaries permit exchange
An Overview of the Cardiovascular System
Figure 20.1
Compare (what is the same) and Contrast (what is different) Pulmonary and Systemic Circuits1.Oxygenated
Deoxygenated2.Pressure3.Arteries Veins4.Color
Atria Thin walled chambers that receive blood
from the vena cavae Ventricles
Thick walled chambers separated from the atria by AV valves
Chordae tendineae Tendinous fibers attached to the AV
valves Papillary muscle and trabeculae
carneae Muscular projections on the inner wall of
ventricles
Internal Anatomy and Organization
1. Right atria Tricuspid valve
2. Right ventricle Pulmonary
valve3. Pulmonary
circuit4. Left atria
Bicuspid valve5. Left ventricle
Aortic valve6. Aorta and
systemic circuit
Blood flow through the heart
The Sectional Anatomy of the Heart
Figure 20.6a, b
Animation: Diagrammatic Frontal Section through the Heart
The Sectional Anatomy of the Heart
Figure 20.6c
Heart chambers and valves
Structure and Function Question:
Why does the human
heart have four chambers?
Structural Differences in heart chambers The left side of the heart is more
muscular than the right side
Functions of valves AV valves prevent backflow of blood from
the ventricles to the atria Semilunar valves prevent backflow into
the ventricles from the pulmonary trunk and aorta
Leaky valves????
Heart chambers and valves
Structural Differences between the Left and Right
Ventricles
Figure 20.7a-c
1. Volume
2. Thickness of wall
3. AV valve
4. Force of contraction
Valves of the Heart
Figure 20.8a
Valves of the Heart
Figure 20.8b
Organization of Heart Tissues
Components of the heart wall include Epicardiu
m Myocardiu
m Endocardi
um
The Heart Wall
Quiz Yourself- pg 453 in lab manual
The heart consists of four chambers Two atria and two ventricles
Major blood vessels of the heart include Inferior and superior vena cavae Aorta and pulmonary trunk
Superficial Anatomy of the Heart
The Superficial Anatomy of the Heart
Figure 20.3a
The Superficial Anatomy of the Heart
Figure 20.3b, c
Arteries: right/ left coronary arteries,
Veins: Great cardiac vein, anterior and posterior cardiac veins
Blood Supply to the Heart
Coronary Circulation
Figure 20.9c, d
By Pass Surgery- Video
Complete Activity 2, 3, 4 Lab 30
The conducting system includes: Sinoatrial (SA) node Atrioventricular (AV) node Conducting cells
Atrial conducting cells are found in internodal pathways
Ventricular conducting cells consist of the AV bundle, bundle branches, and Purkinje fibers
The Conducting System
SA node begins the action potential Stimulus spreads to the AV node Impulse is delayed at AV node Impulse then travels through
ventricular conducting cells Then distributed by Purkinje fibers
Impulse Conduction through the heart
Impulse Conduction through the Heart (figure
18.15)
Figure 20.13
Cardiac Cycle
Systole- contraction (ventricle) Diastole: relaxation (ventricle)
Key Idea: Both atria fill an contract at same time Both ventricles fill and contract at the same time
A Very efficient pump!
Pulmonary Edema
Regulation of Stroke Volume
More stretch = more forceful contraction
Think about rubber bands! High volume of venous return causes
more stretching of myocytes
Factors that increase venous return: 1. slow heart rate (why?) 2. exercise (why)
Regulation of Heart Rate
Normal heart rate is _____________?
Tachycardia and bradycardia……Medulla Oblongata (Brain stem) Sympathetic Parasympathetic Cardiaccelatory Cardioinhibitory Center (vagus nerve) center
SA/AV node SA/AV node
Regulation of Heart Rate
Sympathetic nervous system- speeds up heart rate
epinephrine (adrenaline) , norepinephrine Stress and exercise, high level of calcium
Parasympathetic nervous system- slows heart rate beta blockers, morphine- block epinephrine binding sites calcium channel blockers
Alcohol- decreases activity of the vagus nerve- and the caridoaccelratory center in the brain stem.
