Category: 12th Zoology

Rheumatic Heart Disease (RHD), ICCU – (Intensive Coronary Care Unit)

Post author By Mr. Padeepz
Post date September 18, 2018
No Comments on Rheumatic Heart Disease (RHD), ICCU – (Intensive Coronary Care Unit)

Rheumatic Heart Disease (RHD)

It is a common form of disease found throughout the world. RHD (Rheumatic Heart Disease) 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.

Heart block Echo cardiography Heart Valves

Post author By Mr. Padeepz
Post date September 18, 2018
No Comments on Heart block Echo cardiography Heart Valves

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 (leakiness)
makes the valve unable to prevent backwash of blood. These defects
cause characteristic heart murmurs which can be heard by a doctor.

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 of Atherosclerosis

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 of Atherosclerosis

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).

Angiogram

Angiogram is a special contrast X ray and can be used to detect an
abnormality in a blood vessel such as a narrowing of a large diseased artery.

Coronary Angiography

Coronary angiography is used to image the arteries that supply the
heart muscle with blood. Angiography can image narrowed or blocked
coronary arteries, which are not visible on a normal X-ray. A local
anesthesia is injected and a fine flexible catheter is passed within the femoral
artery, through the aorta and into a coronary artery. A contrast dye is
injected through the catheter and a series of x rays taken. The procedure is
painless.

Coronary Angioplasty

Coronary angioplasty is an operation done to clear flow of blood
when the coronary arteries are narrowed or blocked by fatty deposits with
the help of a baloon catheter. Under local anesthesia, a guide wire is inserted
through the femoral artery in the groin and up into the affected coronary
artery. A baloon catheter is passed up the wire and the baloon is inflated in
the narrowed area to widen it. Sometimes, a metal tube called a stent is
inserted afterward. It keeps the artery open. (Angiogram)

Coronary bypass surgery is an operation to circumvent narrowed
or blocked coronary arteries by grafting additional blood vessels to transmit
blood flow. During this procedure the heart is temporarily stopped and blood
circulation and oxygenation is taken over by a heart lung machine. (Angiogram)

Angina pectoris

Angina is a term that describes a strangling or constrictive
pain. Angina has become synonymous with the heart disorder called Angina
pectoris. This heart disorder refers to chest pain caused by insufficient
supply of oxygen to the heart muscle, usually a result of poor blood supply.
Angina pectoris usually occurs when the demand for oxygen is increased
during exercise and at the time of stress. The pain usually comes on
suddenly. The pain ranges from a tight ache to intense crushing agony. It lasts
for 30 minutes or more and it is not relieved by rest.

Causes of Angina pectoris

(1). Inadequate blood supply to heart due to coronary artery
disease such as atherosclerosis (2). Severe attack of anaemia which
reduces the oxygen carrying capacity of blood. (3). Polycythemia (Increased
number of red blood cells) which thickens the blood, causing it to slow its
flow through the heart muscle. (4). Thyrotoxicosis (a disorder caused by
excessive secretion of thyroxine) can precipitate angina pectoris by making
the heart work harder and faster than its blood supply will permit.

Myocardial infarction

Myocardial infarction is a coronary artery disease
which involves sudden death of part of the heart muscle due to blockage in
the coronary artery. It may cause severe unremitting chest pain.

Causes of Myocardial infarction

The coronary arteries that supply the heart muscle with fresh
oxygenated blood become narrowed. This narrowing is usually due to an
accumulation of droplets of fatty substances, like cholesterol. The fibrous
cover of the fat deposit sometimes rupture, triggering the formation of a blood
clot. If this blood clot blocks the artery, blood flow to an area of the heart
muscle stops, causing myocardial infarction and leads to death of tissue.

Symptoms of Myocardial infarction

(1) Severe heavy crushing pain may spread up to the neck and
in to the arms especially the left arm. (2) Sweating (3) Shortness of breath
(4) Nausea and vomiting (5) Anxiety sometimes accompanied by fear of
dying.
About one in five people experience no chest pain in myocardial
infarction. However, there may be fainting, sweating and pale skin. This
pattern of symptom is known as “silent infarction”. This type of infarction is
common in people with diabetes mellitus or those with elevated blood
pressure.

Risk factors of Myocardial infarction

1. Habitual cigarette smokers have a substantially increased risk of dying
from myocardial infarction.
2. High blood pressure is a major risk factor and the risk increases with
higher pressure.

3. The risk of atherosclerosis and coronary artery disease increases
dramatically in those who are more than 30 percent overweight.
4. A raised blood cholesterol level increases the risk. A high fat diet is also a
factor.
5. Physical inactivity is also a major factor.

Coronary blood vessel and its significance

Post author By Mr. Padeepz
Post date September 17, 2018
No Comments on Coronary blood vessel and its significance

Coronary blood vessel and its significance

There are two main coronary arteries the left and the right. The left one
branches into the left circum flex artery and the left anterior descending artery.
Right main coronary artery and the left coronary arteries branch off from the
aorta, surround and penetrate the heart muscle. Arterioles and capillariesbranch off from the coronary arteries to supply heart muscle with oxygen
rich blood. Deoxygenated blood drains into the coronary veins, which carry
it back into the heart’s right atrium.

Damage to the coronary blood vessel or narrowing of the coronary
vessel leads to coronary artery disease (CAD). Blood flow through the
arteries is restricted, leading to damages of the heart muscle. Heart disorders
like heart attack, myocardial infarction, the chest pain or Angina are
usually caused by CAD. In many parts of the world mortality from
coronary artery disease is rising due to changing life style factors.

Cardiac cycle

The sequential events occuring from the initiation of one heartbeat to
the commencement of the next is called as one cardiac cycle. In this cycle,
the contraction phase is called systole. The relaxation phase is the diastole.

A single heart beat comprises a systole and diastole in both atria and
ventricles.

Atrial systole

There is a continuous flow of blood into the right atrium
through superior and inferior vena cava and coronary sinus. Simultaneously
the left atrium receives blood from 4 plulmonary veins. There is a passive
movement of nearly 70% of the blood. The remaining 30% is pumped into
the ventricles by atrial contraction.

Ventricular filling

When the valves in between atria and ventricles open
nearly two-third of the ventricle is filled. Remaining space gets filled up by
atrial contraction. (Cardiac Cycle)

Ventricular systole

As the atrial systole ends, the action potential
generated by the SA node reaches the AV node and rest of the fibrous
system. It causes contraction of the ventricular wall. Thus ventricular
pressure results. The very strong ventricular pressure pumps the blood into
respective arteries by causing the semilunar valves to open.

Ventricular diastole

Soon after the blood leaves the ventricles there is a
fall in the ventricular pressure. The semilunar valves close and the atrial
valves open to begin the next cycle. (Cardiac Cycle)

Heart sound

The heart sound felt by a stethescope is caused due to the
closure and opening of the valves. The generation of sound is rhythmic. The
first sound is louder (lubb) and of longer duration (0.16-0.90sec). It is due
to closure of the atrioventricular valves at the beginning of the ventricular
systole. The second sound is of shorter duration (dubb) (0.10sec). It is caused
at the end of the ventricular systole by the closure of semilunar valve. The
heart beats at the rate of about 72-80 times per minute in adults. The ventricular
systole causes a wave of distension due to blood flow. It is called as arterial
pulse. It can be felt on the wrist. The pulse rate corresponds to rate of
heartbeat. (Cardiac Cycle)

Circulatory System – Functioning of Human heart

Post author By Mr. Padeepz
Post date September 16, 2018
No Comments on Circulatory System – Functioning of Human heart

The Circulatory System

All cells of our body require constant nutrition and waste removal
since they are metabolically active. Most of the body cells are located at
some distance from the nutrient sources such as the digestive tract and sites
of waste disposal such as kidneys. The cardiovascular system which
consists of the heart, blood vessels and blood, connects the various tissues
of the body. While the heart pumps the blood through the blood vessels, the
blood delivers nutrients and collect waste products.

Functioning of Human heart (Circulatory System)

Heart is a pumping organ. It receives blood from different parts of
the body through the veins that open through inferior and superior vena
cavae and pulmonary veins. While the right atrium receives deoxygenated
blood, the left atrium receives the oxygenated blood from the lungs. When
the wall of the atria contract the right and left atria pump the blood into the
right and left ventricles respectively. A pulmonary trunk arising from the
right ventricle takes away the blood to the lungs for oxygenation. The left
ventricle gives rise to an aorta, from which oxygneated blood is supplied to
the coronary arteries and the systemic circulation of the body. The blood flow between the right atrium and the right ventricle is
regulated by the tricuspid valve. The bicuspid or mitral valve regulates
the flow on the left chambers of the heart. In the pulmonary trunk and the
aorta, back flow of blood is prevented by a set of semilunar valves.

Origin and conduction of heart beat (Circulatory System)

During pumping action of heart, the heart muscles cause rhythmic
contraction and relaxation of the heart chambers in a specific sequence. The
rhythmic, sequential functioning of the cardiac chamber is maintained by
sino-atrial node (SA node), atrio-ventricular node (AV node), bundle of His
and Purkinje fibres.

The SA node situated in the upper, lateral wall of the right atrium is a
small, flattened strip of muscle fibre that is 1.5cm x 3mm in size. The fibres of
the SA node are closely associated with the muscles of auricles. SA node is
capable of generating action potential that can travel throughout the auricles.
The velocity of conduction is 0.3m/sec. The excitation from the SA node
stimulates the AV node. The AV node in turn conducts the stimulus to bundle
of His and Purkinje fibres. These myocardial fibres are found all over the
wall of the ventricles. In the conduction of stimulus through the AV node and
the fibrous system there is a delay in transmission.

Bronchitis – Acute bronchitis, Chronic Bronchitis Causes

Post author By Mr. Padeepz
Post date September 15, 2018
No Comments on Bronchitis – Acute bronchitis, Chronic Bronchitis Causes

Bronchitis

Bronchitis is the inflammation of the bronchi, the air ways that
connect the trachea (wind pipe) to the lungs, resulting in cough that may
produce considerable quantities of sputum (Phlegm). Two forms, of the
disease are recognized as acute bronchitis (sudden onset and short duration)
and chronic bronchitis (Persistent over a long period and recurring over
several years). Both are more common in smokers and in areas with high
atmospheric pollution.

Acute bronchitis :

It is caused by viral infection or by the effect of air
pollutants. Bacterial infection may cause acute bronchitis. Attacks occur more
often in winter. Smokers, babies, the elderly and people with lung diseases
are particularly susceptible.

Chronic Bronchitis :

It is a form of bronchitis in which sputum is coughed up on most days
for atleast three consecutive months. The disease results in narrowing and
obstruction of the air – ways in the lungs. It often coexists with another form
of lung disease, emphysema (widening of alveoli). Chronic bronchitis and
emphysema together are called chronic obstructive lung disease (COLD) or
chronic obstructive airways disease.

Causes :

Pollution and smoking are the causes of chronic bronchitis. It
stimulates the production of mucus in the lining of the bronchi.

Rheumatic Heart Disease (RHD)

ICCU – (Intensive Coronary Care Unit)

Related Topics in Zoology:

Heart block

Echo cardiography

Heart Valves

Related Topics in Zoology:

Atherosclerosis

Causes of Atherosclerosis

Risk factors of Atherosclerosis

Related Topics in Zoology:

Angiogram

Coronary Angiography

Coronary Angioplasty

Related Topics in Zoology:

Angina pectoris

Causes of Angina pectoris

Related Topics in Zoology:

Myocardial infarction

Causes of Myocardial infarction

Symptoms of Myocardial infarction

Risk factors of Myocardial infarction

Related Topics in Zoology:

Coronary blood vessel and its significance

Related Topics in Zoology:

Cardiac cycle

Atrial systole

Ventricular filling

Ventricular systole

Ventricular diastole

Heart sound

Related Topics in Zoology:

The Circulatory System

Functioning of Human heart (Circulatory System)

Origin and conduction of heart beat (Circulatory System)

Related Topics in Zoology:

Bronchitis

Acute bronchitis :

Chronic Bronchitis :

Causes :

Related Topics in Zoology: