Human heart short notes :-define, function,properties of cardiac muscle. ~ Statusdeewane

HEART DEFINITION:-
Heart is muscular and hollow organ.
Heart is located between to lungs,heart pump blood throughout circulatory system.
Heart made up four chamber two atrium and two ventricles.
heart size 12×9 cm.

Human Heart

Four valves of heart
• bicuspid
• Aorta
• Tricuspid
• Pulmonary

Function:-
•The heart pumps oxygen and nutrient
rich blood to the organs, tissues and
cells of the body, and eliminates
waste products.

•Heart remove waste products.
.
•Blood is carried from the heart
to the organs through arteries,
arterioles and capillaries

•Blood returns to the heart
through venules and veins.

Layers of heart:-
•Pericardium:
The heart is surrounded by a fibro serous sac called the pericardium.
The function of the pericardium is:
•To limit cardiac distension and restrict excessive movement
• To protect and lubricate
The pericardium is composed of:
• Visceral pericardium
• Parietal pericardium
• Pericardial cavity

Endocardium:-
• Innermost/deepest layer of the heart
• Lines the heart chambers and the valves
• Smooth thin lining to reduce friction of
blood flow through the chambers

Myocardium:-
• Middle, thickest layer of the heart.
• Contains the muscle fibres
which are responsible for pumping.

•TYPES OF BLOOD VESSELS:-
•ARTERIES:-Carry blood away from the heart The aorta is the largest artery.

•VEINS:-Carry blood back to the heart.(containvalves)The vena cava is the
largest vein.

•CAPILLARIES:-Exchange ofwater,oxygen
, carbon dioxide and many other nutrients
,waste and chemicals substances between blood .

•PULMONARY CIRCULATION:-
he carriage of oxygen-depleted blood awayfrom the heart to the lungs via the pulmonary artery he return of oxygen-rich blood to the heart via the pulmonary vein.
ulmonary circulation and the heart
•he inferior and superior vena cava carry oxygen depleted blood to the relaxed right atrium of the heart.
•he right atrium contracts and blood travels through the tricuspid valve into the relaxed right ventricle.
•he right ventricle contracts, the blood is pumped through the pulmonary valve into the pulmonary artery to the lungs.
•as exchange occurs in the lungs.
•o2 is released and oxygen is absorb.

•SYSTEMIC CIRCULATION :-Systemic circulation is
• The carriage of oxygen-rich blood
away from the heart to the body
• The return of oxygen-depleted blood back to the heart.

Systemic circulation and the heart:-
• Oxygen rich blood travels from the lungs via the pulmonary veins to the left
atrium.
• The left atrium contracts, and blood flows through the mitral valve into the
relaxed left ventricle.
• The strong left ventricle contracts and pumps oxygen rich blood through the
aortic valve into the aorta.
• The aorta carries blood to the organs of the body.

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•PROPERTIES OF CARDIAC MUSCLE:-
cardiac muscle has certain characteristics.they are:
1.CONTRACTILITY:-by contraction of the cardiac muscle the heart pump out of its chambers.

2.CONDUCTIVITY:-the impulse for cardiac contractions are conveyed through a specialsed conduction system.

3.RHYTHMICITY:-heart muscle has the inherent property of rhythmic contractions.cardiac contractions occur in regular Fashion.the two atria and ventricles contract alternately.

4.REFRACTORY PERIOD:-during systole,the heart does not respond to any other stimuli,however strong it may be.this is called as refractory period.