Table of contents |
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Introduction |
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Double Circulation |
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Regulation of Cardiac Activity |
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Disorders of Circulatory System |
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The circulatory system is responsible for the transportation of nutrients and gases like oxygen, for the body and metabolic waste products away from the body. The heart and the lungs play an important role in circulating and purification of blood throughout the body. But is the heart the only organ that helps in purification? Let’s have a brief study on double circulation and the relevant organs involved.
Layers of Arteries and Veins
The human heart is divided into four chambers:
Further, the heart is connected to the lungs through the pulmonary artery and vein. In double circulation, there are two pathways in which the blood flows. They are:
Systemic circulation carries oxygenated blood from the left ventricles to the tissue capillaries.
In the pulmonary circulation, the blood circulation starts from the right atrium to the left atrium. In this pathway:
Double circulation supports a strict separation of both oxygenated and deoxygenated blood. Therefore, this circulation ensures that the body always has a dedicated supply of oxygen and also, it improves body efficiency. This is also one of the reasons why mammals can maintain their body temperatures. Apart from the double circulation, a third portal system also exists to improve circulation efficiency.
Intrinsic Regulation: The heart's normal activities are regulated intrinsically by specialized muscle tissue known as nodal tissue. This is why the heart is called myogenic.
Role of Neural Centre: A special neural center in the medulla oblongata can moderate cardiac function through the autonomic nervous system (ANS).
Sympathetic Nervous System: Neural signals from the sympathetic part of the ANS can increase:
Parasympathetic Nervous System: Neural signals from the parasympathetic part of the ANS can decrease:
Adrenal Medullary Hormones: Hormones from the adrenal medulla can also increase cardiac output.
Hypertension refers to blood pressure that is higher than normal, specifically above 120/80 mm Hg. In this measurement:120 mm Hg represents the systolic (pumping) pressure, while 80 mm Hg indicates the diastolic (resting) pressure.
If an individual's blood pressure consistently measures 140/90 mm Hg or higher, it indicates hypertension. High blood pressure is a serious condition that can lead to heart diseases and adversely affect vital organs such as the brain and kidneys.
(ii) Atherosclerosis/ Coronary Artery Disease
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1. What is the difference between single and double circulation in the circulatory system? | ![]() |
2. How does the heart regulate cardiac activity? | ![]() |
3. What are common disorders of the circulatory system? | ![]() |
4. How can double circulation benefit mammals and birds compared to single circulation? | ![]() |
5. What lifestyle changes can help prevent disorders of the circulatory system? | ![]() |