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Chapter: 11th 12th standard bio zoology Human Body higher secondary school

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Atherosclerosis, Heart block, Rheumatic Heart Disease (RHD)

Atherosclerosis is narrowing of the arteries caused by plaques on their inner linings. These plaques are composed mainly of fats deposited from the blood stream. They disrupt the normal flow of blood through the affected artery. Atherosclerosis encourages thrombus and embolus (fragment of blood clot).

Atherosclerosis

 

Atherosclerosis is narrowing of the arteries caused by plaques on their inner linings. These plaques are composed mainly of fats deposited from the blood stream. They disrupt the normal flow of blood through the affected artery. Atherosclerosis encourages thrombus and embolus (fragment of blood clot). Men are affected earlier than women because women are protected by natural oestrogen hormones.

 

Causes : Narrowing of the vessel is due to the development of raised patches called plaques. These plaques consists of athroma (fat and oil mixture), decaying muscle cells, fibrous tissue, clumps of blood platelets, cholesterol and calcium (abnormal blood clot)

 

Risk factors :

 

Cigarette smoking, Hypertension, male gender, obesity, physical inactivity, diabetes mellitus, heredity, aggressive personality. Severe effects of atherosclerosis is stroke (loss of blood supply to brain), heart attack (loss of blood supply to heart).


Heart block

 

Complete failure of the system that conducts electrical impulses from the upper to the lower heart chamber is called the heart block. Normally,

electrical impulses pass from the sinu auricular node to the atrio-ventricular node in the right atrium and then to the ventricle. In complete heart block, the impulses cannot reach the ventricle. This defective production of the sinu atrial impulses and its conduction in the heart is called heart block.

 

Echo cardiography

 

Echo cardiography is a technique that uses ultra sound waves to image the interior of heart. It is used to diagnose disorders of the heart and the heart valves. The test is usually done by using an ultrasound transducer (probe) placed on the skin of the chest directly over the heart. In some cases a small probe is passed down the oesophagus.

 

Heart Valves :

 

Heart valves are essential for precisely controlling the flow of blood in between auricles and ventricles and between the heart and major blood vessels. The valves are delicate pockets and their function is to prevent any backward flow of blood. The heart valve's functioning is vital for the efficiency of the heart as a pump.

 

The opening and more particularly the closing of heart valves during each heart cycle are responsible for heart sounds. Any of the four heart valves may be affected by stenosis (narrowing) which causes the heart to work harder to force blood through the valve. Incompetence or insufficiency (leaki-ness) makes the valve unable to prevent backwash of blood. These defects cause characteristic heart murmurs which can be heard by a doctor.

 

 Rheumatic Heart Disease (RHD)

 

It is a common form of disease found throughout the world. RHD is a crippling desease. Rheumatic fever develops due to an infection usually of the throat, caused by streptococcal bacteria. The condition is caused by the immune system attacking the body's own tissues in response to the infection. The symptoms of Rheumatic fever may include high fever, pain and swelling in bone joints.

 

ICCU - (Intensive Coronary Care Unit)

 

All major hospital in urban towns and cities have. Intensive Coronary Care Unit to care for people in a critical or unstable condition.

They require continuous monitoring. This unit has a wide variety of sophisticated equipments for constantly monitoring the condition of the seriously ill patient. The patient may be connected to a ventilator to maintain breathing. Body fluids and blood sugar levels are maintained by intra venous infusion of salts and glucose. Nutrients may also be supplied intravenously. Urine is collected through a catheter. Blood pressure is continuously monitored by an automatic sphygmomanometer. Heart rate and rhythm are monitored by an ECG machine. Results are often relayed to a central monitoring unit. Monitors are fitted with alarms to alert the staff if there is any dangerous variation from the normal range.


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