Narad's beneficial role The moral fibre, personality the character of sage Narada has to be fully grasped against the negative standing that is latent in the term 'kalaha Priya' attributed to him, pointed out Sri k.Srinivasam in a courage. This point is explain in detail by Vyas in the Devi Bhagwat Puran as an answer to the issue that janamejaya rises with reference to kama's as killing of 6 infants who were born to Devaki. It is said that Kansas decided to spare the 1st new born infants of Devaki knowing that only the eighth child was a real threat . But Narad intervences and changes his decision. So JanameJaya wonder how Narad, adeva Rishi, age of Great reputation, and Janani, can prompt kamsa thus . How did the sage, the embodiment of Dharma, stop down to a bit the killing of infants? Is this not considered as a serious crime that deserve the most grave punishment? Vyas explain that Northern character should be understood in prop...
Circulation plays an important role in our body ,it circulates oxygen ,blood and minerals to our living cell which is necessary for their growth and development .
CIRCULATORY SYSTEM
- Circulatory system was discovered by William Harvey in 1628.
- Circulatory system can be either of open type or closed type.
- In open circulatory system,blood does not flow in vessel.
- The circulatory system consists of heart and blood vessels.
The heart is a hollow fibro muscular organ of somewhat conical aur pyramidal form with upper broad part the base and the lower narrow apex, which is slightly directed to the left .
Structure of heart
- Human heart is situated in the pericardial cavity.
- The hard wall is made of three layer, ie. Pericardial myocardial and endothelium.
- Pericardian fluid is the fluid present between layer of heart wall. It allows Frictionless movement of heart and protect it from mechanical shock.
- In males weight of heart is about 280 - 340 gram.while in female it is about 230-280gram.
- Weight of heart of a newborn baby is 20 gram.
- Human heart is consist of 2 artrium and two ventricles .
- 1Right auricle or atrium
- It receives deoxygenated blood from superior vena cave and inferior Vena cava .
- Right auricle opens in right ventricle through a wide circular right auricul oventricular aperture guarded by tricuspid walve .
- Tricuspid valves Regulate unidirectional flow of blood from right auricle to right ventricle.
- 2Right ventricle
It gives of a large blood vessel called pulmonary artery artery leading to the lungs which carries deoxygenated blood to the lungs. Semilunar wall stops blood to return back to ventricle.
- 3 Left auricle or atrium
- It receives oxygenated blood from lungs through pulmonary veins.
- They have no valve.
- Left auricle opens in a left ventricle by an aperture called a left auriculoventricular aperture.
- This aperture is guided by biscuspid valve (mitral valve )
- Biscuspid valve prevants backflow of blood from the left auricle to left ventricle.
- 4Left ventricle
- It gives off a large blood vessel called the aorta.
- Aorta carries oxygenated blood to various body parts.
- The thickest Part of the human heart is the wall of the left ventricle ventricle.
Blood circulation in human is an example of double circulation. Pulmonary circulation and systematic circulation.
- Pulmonary circulation - in this type of circulation , the deoxygenated blood is used by the right ventricle to the lungs of oxygen through pulmonary artery. The oxygenated blood is brought back to left atrium of heart through pulmonary vein.
- Systematic circulation - in this type of circulation, the oxygenated blood brought to left arterium and goes to left ventricle and then passed on to different body parts through aorta.
Cardiac Cycle
- The study of structure and functioning of heart is called as cardiology.
- Heart constantly construct and relax, due to which transportation of blood occurs in the whole body.
- Cardiac cycle in the event, during with some heartbeat or one cycle of systole and diastol of cardiac muscles occurs.
- Cardiac cycle consists of systole and diastole of artria and ventricles.
- The cardiac impulse start from SA node via conducting system, this impulse is conducted to all part of heart.
- SA node is called the pacemaker of heart.
- Rate of heartbeat in human is a 72 to 75 per minute.
- One cardiac cycle takes 0.8 seconds.
The beating of heart produces sound heard by sthescope .
First sound (lubb)-is a long and louder sound created by the closer of artriventricular valve (tricuspid and biscupid) at the beginning of ventricular systole .
Second sound (dupp)-is a short and created by the closure of semilunar valve toward the end of a ventricular systole (beginning of ventricular diestole ).
Cardiac output
It is the amount of blood pump by the heart per minute.
Cardiac output=normal heart rate of an adult perminute×amount of blood pumped by heart per min
=72×70=5040 ml per min (5lit/min).
Blood vessels
In circulatory system oxygenated and deoxygenated blood is transported to different part of body through different vessels name the artery , capillaries and veins .
Difference between arteries and veins
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