Download Heart chambers and valves

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 Circuits
1. Oxygenated Deoxygenated
2. Pressure
3. Arteries Veins
4. Color
Internal Anatomy and Organization

Atria


Ventricles


Thick walled chambers separated from the atria by AV
valves
Chordae tendineae


Thin walled chambers that receive blood from the vena
cavae
Tendinous fibers attached to the AV valves
Papillary muscle and trabeculae carneae

Muscular projections on the inner wall of ventricles
Blood flow through the heart
1.
Right atria
Tricuspid valve
2.
Right ventricle
Pulmonary valve
3.
4.
Pulmonary circuit
Left atria
Bicuspid valve
5.
Left ventricle
Aortic valve
6.
Aorta and systemic
circuit
The Sectional Anatomy of the
Heart
Animation: Diagrammatic Frontal Section through the Heart
Figure 20.6a, b
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?
Heart chambers and valves

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????

Structural Differences between the
Left and Right Ventricles
1. Volume
2. Thickness
of wall
3. AV valve
4. Force of
contraction
Figure 20.7a-c
Valves of the Heart
Figure 20.8a
Valves of the Heart
Figure 20.8b
Organization of Heart Tissues
The Heart Wall

Components
of the heart
wall include
Epicardium
 Myocardium
 Endocardium

Quiz Yourself- pg
453 in lab manual
The Heart Wall and Cardiac Muscle
Cells
Figure 20.5a-c
Superficial Anatomy of the Heart

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

The Superficial Anatomy of the
Heart
Figure 20.3a
The Superficial Anatomy of
the Heart
Figure 20.3b, c
Blood Supply to the Heart


Arteries: right/
left coronary
arteries,
Veins: Great
cardiac vein,
anterior and
posterior cardiac
veins
Coronary Circulation
Figure 20.9c, d
By Pass Surgery-
Video
Complete Activity 2, 3, 4
Lab 30
The Conducting System

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

Impulse Conduction through the
heart





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 (figure 18.15)
Figure 20.13
Cardiac Cycle
Key Idea: Both atria fill an contract at same time
Both ventricles fill and contract at the same time
A Very efficient pump!
Systole- contraction (ventricle)
Diastole: relaxation (ventricle)
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.