Blood circulatory System

The system responsible for circulating blood and lymph throughout the body that supplies nutrients and oxygen to the cells and removes various waste products .It consists of the heart, blood, blood vessels, lymph, etc.

Blood and its composition

The familiar red fluid in the body that contains white and red blood cells, platelets, proteins, and other elements. The blood is transported throughout the body by the circulatory system. Blood functions in two directions: arterial and venous. Arterial blood is the means by which oxygen and nutrients are transported to tissues while venous blood is the means by which carbon dioxide and metabolic by-products are transported to the lungs and kidneys, respectively, for removal from the body.

Plasma: It is the nonliving portion of the blood, which consist 90% of water and 10% of minerals. It occupies 55% of total volume of blood and performs the following major functions:

It transports digested food to different organs and tissues of the body. Waste substances from the tissues are removed and carried to the related excretory organs

for their organs for their elimination. It removes the major portion of carbon dioxide from the tissue. The hormones secreted by various endocrine and exocrine glands are transported

by circulatory system It regulates the body temperature. It contains fibrinogen (protein) and prothrombin hormone that helps in clotting of the

blood after clots.

Blood cells

a. Red blood cells or erythrocytes

They are circular, biconcave, disc shaped and non-nucleated cells. They are formed in Red bone marrows and destroyed in the spleen. Their life span is very short that is 4 months. In one cubic milliliter of the blood of a healthy person 42-45 lakhs of RBC present. RBC contains iron pigment called hemoglobin that carries oxygen from place to place in form of oxyhemoglobin. When hemoglobin is exposed to oxygen, it turns into red. So the blood is red in color. If RBC is less in blood then a person is suffering from anemia, as there is not enough hemoglobin to transport oxygen. They are also called as oxygen-carriers.

b. White blood cells [leukocytes]

They are irregular in shape. They form in bone marrow and mature in lymph node or bone marrow. Their life span is about of 15 days. In one cubic milliliter of blood of a healthy person there are 6000- 10000 WBC present. WBC maintains immunity of our body. They fight against germs and keep us safe from disease. If WBC count is less in our body than normal we suffer from disease called leucopenia and excess called leukemia [Blood cancer] .

c. Platelets [Thrombocytes] They are rod shaped without nucleus. They are formed in bone marrow and destroyed in spleen. Their life span is of 2-3 days. In one cubic milliliter of blood of a healthy person there are 2 to 4 lakhs platelets present. They are responsible for clotting of blood and healing of wounds.

Functions of blood

Transportation: Blood transports oxygen from lungs to tissue and carry carbon dioxide from tissue to their excretory organs. It carries hormones to their target organs. It helps to transport minerals up to tissue and byproducts to their excretory organs.

Regulation: Body temperature is regulated by blood. Protection: Blood maintains the immunity of the body, which fights against disease. Blood

produces antibody in response to antigen and protect from germs.

RBCs WBCs Oval, biconcave and non-nucleated Amoeboid and nucleated

Small in size Large in size More in number Less in number Helps in respiration Helps in immunity power

The heart

It is the major pumping organ associated with circulatory system. Human heart contains four chambers, upper two are called Auricles and are divided by an auricular septum into left and right and lower two are called ventricles divided into two by ventricular septum into left and right. In mammalian heart right side is responsible for collecting impure blood and left side is responsible for collecting pure blood.

One thin membrane covers the heart externally that is called pericardial membrane. The cavity between this membrane and heart wall is called pericardial cavity that is filled by thick, gelatinous fluid called pericardial fluid. Pericardial fluid protects the heart from external injury, keeps heart moist and makes movement heart frictionless.

Parts of heart

a. Right auricle: It receives deoxygenated blood from different parts of the body and pumps it into the right ventricle.

b. Right ventricle: It receives deoxygenated blood from the right auricle and pumps into the lungs for it to become oxygenated.

c. Left auricle: It receives pure oxygenated blood from lungs and pumps it to left ventricle

d. Left ventricle: It receives oxygenated blood from left auricle and pumps it to different parts of the body.

Functions of four blood vessels of the heart

i. Venacava: Venacava transport deoxygenated blood from different parts of the body into the right auricle of the heart.

ii. Pulmonary arteries: They carry deoxygenated plod from the right ventricle of the heart to the lungs for oxygenation.

iii. Pulmonary vein: They carry oxygenated blood from lungs to the left auricle of the heart. iv. Aorta: It carries pure oxygenated blood from the left ventricle of the heart.

Functions of four valves of heart

1. Tricuspid / Right atrio-ventricular valve: It blocks the backflow of blood from the right ventricle to the right auricle when right ventricle contracts.

2. Bicuspid / Mitral / Left atrio-ventricular valve: It blocks the backflow of blood from the left ventricle to the left auricle when left ventricle contracts.

3. Pulmonary / Pulmonic valve: It blocks the backflow of blood from pulmonary artery to the right ventricle when ventricle relaxes.

4. Aortic valve: It blocks the backflow of blood from aorta to the left ventricle relaxes.

Working of heart

Wall of right atrium contains natural pacemaker from where the waves of contraction of heart starts. Heart pumps blood with the help of regular contraction and relaxation. During circulation blood flows following route:

Impure blood in right auricle ----- >Right ventricle ( by opening of Tricuspid valve) ------> Pulmonary artery (by the opening of pulmonary valve) -------> Lungs ( Oxygenation) -------> Pulmonary vein ------> Left auricle ------> Left ventricle ( by opening of bicuspid valve) -------> Aorta ( by opening of Aortic valve) -------> tissues of body (exchange of gases and waste products) --------> Venacava -------> Right auricle.

Blood pressure

The pressure exerted by blood in blood vessel is called blood pressure. The normal blood pressure of a healthy person is 120/80 mm of Hg. 120 represents systolic blood pressure (blood pressure at the time of contraction of heart) and 80 represents diastolic blood pressure (blood pressure at the time of relaxation of heart). Blood pressure is measured by sphygmomanometer. Blood pressure varies according to age, sex mental condition, physical condition etc.

Heart beat

Heart is the major pumping organ of the body. This rhythm of contraction and relaxation of atrium and ventricles is called heart beat. The normal heart beat rate for a healthy person is 72 to 80 beats per minute. Heart beat also varies from person to person depending on age, sex mental condition, physical condition etc.

It is a fluid connective tissue flowing in its closed path called blood vessels. It is red in color due to presence of iron rich pigment called hemoglobin in RBC.

Blood vessels

Closed path through which blood flows to different parts of the body are called blood vessels. They are of three types:

1. Artery: These blood vessels carry blood away from the artery. Except pulmonary artery all other arteries carry oxygenated blood. They have thick wall because blood pressure in the artery is high. Arteries do not contain valves. The fine branches of arteries are called arterioles.

2. Veins: Those blood vessels which carry blood towards heart are called veins. Except pulmonary vein they carry deoxygenated blood. They are thin walled as the blood pressure is low in veins. As there is low blood pressure in veins there is a chance for the backflow of blood which is prevents by the presence of valves. The larger structure of veins is called Venacava and smaller branches of veins are called venules.

3. Capillaries: The fine branches of arterioles and venules are called capillaries. Capillaries go into the tissue for gaseous and nutrient exchange. It also helps in ultra filtration (relative filtration) in kidney

Types of circulation

Circulation in human beings is called double circulation as the blood enters into the heart for two times in one complete course of circulation. Mainly there are two parts of circulation:

1. Pulmonary circulation: The exchange of blood between heart and lungs is called pulmonary circulation. It is comparatively short route of circulation. During pulmonary circulation blood flows through these paths:

Impure blood in right auricle ----- >Right ventricle (by opening of Tricuspid valve) ------> Pulmonary artery (by the opening of pulmonary valve) -------> Lungs (Oxygenation) -------> Pulmonary vein ------> Left auricle

2. Systemic circulation: The exchange of blood between heart and various parts of the body except lungs is called systemic circulation. This route is longer than pulmonary circulation. In systemic circulation blood flows through:

Left auricle ------> Left ventricle (by opening of bicuspid valve) -------> Aorta (by opening of Aortic valve) -------> Superior and inferior arteries ------> tissues of body (exchange of gases and waste products) (through capillaries) --------> Veins --------> Venacava -------> Right auricle

Some diseases related to blood circulatory system

High blood pressure

Anyone whose blood pressure is 140/90 mmHg or more for a sustained period is said to have high blood pressure, or hypertension.

Blood pressure is usually divided into five categories:

Hypotension (low blood pressure) Systolic mmHg 90 or less, or Diastolic mmHg 60 or less Normal Systolic mmHg 90-119, and Diastolic mmHg 60-79 Prehypertension Systolic mmHg 120-139, or Diastolic mmHg 80-89 Stage 1 Hypertension Systolic mmHg 140-159, or Diastolic mmHg 90-99 Stage 2 Hypertension Systolic mmHg over 160, or Diastolic mmHg over 100

Causes of High Blood Pressure

Essential high blood pressure (primary high blood pressure) - no cause has been identified.

Secondary high blood pressure - the high blood pressure has an underlying cause, such as kidney disease, or a specific medication the patient is taking.

1. Smoking and alcohol

2. Overweight or obese 3. Lack of physical activities 4. Stress 5. Chronic kidney diseases and thyroid disorder 6. Sleep apnea caused snoring 7. Diabetes 8. Ethnic background 9. Temperature 10. Family History

Prevention of high blood pressure 1. Regular Exercise 2. Reducing alcohol and smoking 3. Eating healthily 4. Lowering salt intake 5. Losing weight 6. Lowering caffeine consumption 7. Relaxation Techniques 8. Sleep

Diabetes [diabetes mellitus]

Diabetes is a disease that affects your body’s ability to produce or use insulin. Insulin is a hormone. When your body turns the food you eat into energy (also called sugar or glucose), insulin is released to help transport this energy to the cells. Insulin acts as a “key.” Its

chemical message tells the cell to open and receive glucose. If you produce little or no insulin, or are insulin resistant, too much sugar remains in your blood. Blood glucose levels are higher than normal for individuals with diabetes. There are two main types of diabetes: Type 1 and Type 2.

When you are affected with Type 1 diabetes, your pancreas does not produce insulin. Type 1 diabetes is also called juvenile diabetes, since it is often diagnosed in children or teens. This type accounts for 5-10 percent of people with diabetes.

Type 2 diabetes occurs when the body does not produce enough insulin, or when the cells are unable to use insulin properly, which is called insulin resistance. Type 2 diabetes is commonly called “adult-onset diabetes” since it is diagnosed later in life, generally after the age of 45. 90-95 percent of people with diabetes have this type. In recent years Type 2 diabetes has been diagnosed in younger people, including children, more frequently than in the past.

Symptoms of diabetes

1. Extreme thirst 2. Frequent urination 3. Blurry vision 4. Extreme hunger 5. Increased tiredness 6. Unusual weight loss 7. Slow healing of wounds 8. Irritability

Prevention of Diabetes

1. Changing life styles 2. Reducing body weight 3. Reduce stress, avoiding alcohol, smoking tobacoo etc. 4. Regular exercise and physical activity 5. Healthy food focused on green vegetables and fruits.

Uric Acid

Uric acid is a chemical created when the body breaks down substances called purines. Purines are found in some foods and drinks. These include liver, anchovies, mackerel, dried beans and peas, and beer.

Most uric acid dissolves in blood and travels to the kidneys. From there, it passes out in urine. If your body produces too much uric acid or does not remove enough if it, you can get sick. A high level of uric acid in the blood is called hyperuricemia.

Causes of gout/ gouty arthritis

Gout is the most common form of inflammatory arthritis. It is caused by an elevation of serum uric acid levels that cause crystals to accumulate in the joints, which bring on a gout flare.

1. Having a family history of gout 2. Being overweight 3. Having kidney problems 4. Lead exposure 5. Drinking too much alcohol 6. Taking certain medications like diuretics or niacin

Prevention of Uric acid

1. Apple cider vinegar 2. Excess water 3. Lemon juices 4. Cherries

5. Olive oils 6. Low purine diet should be taken 7. Legumes, animal protein, yeast, mushroom, asparagus, beer etc should avoid.