Post on 15-Apr-2017
Muscular System:Cardiac Muscle
Muscular System
Cardiac Muscle • Only found in the HEART.• Involuntary (Autonomic Nervous System)• Moderate Contraction• Striated• Nuclei is centrally located
• Branched• Abundant in mitochondria• Each cell have and average
length o 50-100um and, 15um width
• Each fiber is envelope with ENDOMYSIUM
• The fascicle is surrounded by PERIMYSIUM
• Intercalated discs
Muscular System
Cardiac Muscle
• Purkinje fibers are non-contractile but are specialized to initiate and conduct the electrical impulse that controls cardiac contraction.
• The chain of events that occurs during contraction of cardiac muscle cells is identical to the skeletal muscle cells.
• Unlike skeletal muscle cells, cardiac muscle cells contract without neural impulse.
The Human Heart
Position and Location
• Lies within the pericardium in middle mediastinum
• Behind the body of sternum and the 2nd to 6th costal cartilages.
• In front of the 5th to 8th thoracic vertebrae
• A third of it lies to the right of median plane and 2/3 to the left
• Anterior to the vertebral column, posterior to the sternum
The Human Heart
Description
Weight: 250-300gApproximately the size of
your fist.Pumps: 70ml/beatWorks: 70 beats/minute
Layers of the Heart
Pericardium
Composed of:
• A superficial FIBROUS PERICARDIUM.• A deep two-layer serous pericardium.• The PARIETAL LAYER lines the internal surface of the fibrous
pericardium.• The VISCERAL LAYER or EPICARDIUM lines the surface of the
heart.• They are separated by the fluid-filled pericardial cavity called
the PERICARDIAL CAVITY.
Pericardium – a double-walled sac around the heart
Layers of the Heart
Myocardium
Endocardium
• Thickest layer of the heart• Thickest in left ventricle because must
pump hard to overcome high pressure of systemic circulation
• Right atrium the thinnest because of low resistance to back flow
• Consist of cardiac muscle cells = myocytes• Different from smooth or skeletal
muscle cells due to placement of nuclei, cross striations, and intercalated disks
• The myocardium‘s smooth inner lining, Innermost layer
• Composed of:Simple squamous epithelium (endothelium)
Fibrous Pericardium
Serous Pericardium(Parietal Layer)
Pericardial Cavity(Pericardial Fluid)
Myocardium
Serous Pericardium(Parietal Layer)
Endocardium
Epicardium
Parts of the Heart
Septum
Inter-atrial septum
Interventricular septum
• Located between right and left atria.• Contains
Fossa ovalis – remnant of foramen ovale• Foramen ovale – opening of
interatrial septum of fetus
• Located between right and left ventricles
• Upper membranous part • Thick lower muscular part
A thin partition or membrane that divides two cavities or soft masses of tissue in an organism.
Right Atrium Left Atrium
Right Ventricle
Left Ventricle
Atrioventricular Valves
Tricuspid Valve
Mitral Valve
Semilunar Valves
Pulmonary Valve
Aortic Valve
Parts of the Heart
Cardiac Muscle
Right Heart
Left Heart
Receives venous blood from systemic circulation via superior vena cava and inferior vena cava into right atrium.
Receives oxygenated blood from the pulmonary vein pumps blood into systemic circulation.
Parts of the Heart
Sulcus:
4 Sulcus/Grooves of the Heart
• Coronary sulcus (circular sulcus) – marks the division between atria and ventricles, contains the trunks of the coronary vessels and completely encircles the heart
• Interatrial groove - separates the two atria and is hidden by pulmonary trunk and aorta in front
• Interventricular grooves - anterior and posterior, mark the division between ventricles (which separates the RV from the LV), the two grooves extend from the base of the ventricular portion to a notch called: the cardiac apical incisures
a long narrow slit or groove that divides an organ into lobes.
Major Vessels of the Heart
Vena Cava
Superior Vena Cava
Inferior Vena Cava
One of the two main veins that bring deoxygenated blood from the body to the heart.
Carries blood from the lower part of the body to the heart.
Vessels returning blood to the heart include:
Major Vessels of the Heart
Coronary sinus
Right and left pulmonary
veins
• Opens into the right atrium• Returns deoxygenated blood
from heart muscle (coronary veins)
• Open into the left atrium• Return oxygenated blood from
lungs
Major Vessels of the Heart
Pulmonary trunk
Ascending Aorta
• Carries deoxygenated blood from right ventricle to lungs
• Splits into right and left pulmonary arteries
• Carries oxygenated blood away from left atrium to body organs
• Three major branches• Brachiocephalic• Left common carotid, • Left subclavian artery
Vessels conveying blood away from the heart include:
Parts of the Heart
Atria
Right Atrium
Left Atrium
The right upper chamber of the heart. The right atrium receives deoxygenated blood from the body through the vena cava and pumps it into the right ventricle which then sends it to the lungs to be oxygenated.
Left atrium receive oxygenated blood through the pulmonary vein. The blood is then pumped into the left ventricle chamber of the heart through the mitral valve.
Parts of the Heart
Ventricles
Right Ventricle
Left Ventricle
The right ventricle is the chamber within the heart that is responsible for pumping oxygen-depleted blood to the lungs. It is located in the lower right portion of the heart below the right atrium and opposite the left ventricle.
The left ventricle receives oxygenated blood from the left atrium via the mitral valve and pumps it through the aorta via the aortic valve, into the systemic circulation.
Parts of the Heart
Valves
Atrioventricular
Semi-lunar
• Tricuspid – found between Right Atrium and Right Ventricle
• Mitral – found between Left Atrium and Left Ventricle
• Pulmonic – located between the right ventricle and the pulmonary artery.
• Aortic
Inferior Vena Cava
Superior Vena Cava
Right Atrium
Right Ventricle
Pulmonary Arteries
Pulmonary Veins
Left Atrium
LeftVentricle
Aorta
Circulation of Blood through the Heart