Body Fluids And Circulation

Phagocytotic activity is the process in which a live cell eats up other cells like cancer cells, dead and damaged cell etc. Basophils do not exhibit phagocytic activity.

The common symptoms observed in people infected with Dengue fever are significant decrease in platelet count also known as Thrombocytopenia. When Dengue fever attacks, the virus combines with platelets and destroys them.

The volume of blood pumped out by the Rt and Lt ventricles is same as each ventricle pumps 70ml of blood in each cardiac cycle.

Neural signals obtained from sympathetic system stimulate heart rate and stroke volume.

Coagulation of blood is the process in which liquid form of blood converts into gel form. This happens to stop bleeding and hence the loss of blood. For coagulation of blood clotting factors are required, two of which are Calcium ions and platelet factors.

In a normal ECG following waves are present:

1. P Wave : It represents Atrial Depolarisation

2. QRS Wave : It represents Ventricular Depolarisation

3. T Wave :It represents Ventricular Repolarisation.

In the ECG of a normal healthy individual Repolarisation of atria would not be seen.

Erythrocytes or RBC’s lack nucleus. This is because the lack of nucleus increases RBC’s surface area and enables it to have more Haemoglobin which is required for transport of gases.

1.Myogenic heart, which is able to generate cardiac contraction independent of the nervous input. The contraction is initiated at the SA node or Sinoatrial node (group of cells present in the right atrium of heart).

2.After which this wave of contraction reaches AV node or Atrioventricular node.

3.Finally the wave reaches the Purkinje fibre initiating the heartbeat.

These cells are involved in inflammatory reaction and release Serotonin, Heparin and Histamine to produce an inflammatory response.

The second heart sound (dubb) is associated with the closure of

Semilunar valves. Sound is produced when the Ventricular Diastole begins, ventricles relax and the semilunar valves close making a ‘dub’ sound marking the end of ventricular systole. It is a very short and sharp sound.

In a normal ECG following waves are present:

4. P Wave : It represents Atrial Depolarisation

5. QRS Wave : It represents Ventricular Depolarisation

6. T Wave: It represents Ventricular Repolarisation.

Heartbeats per minute=72 heart beats

Stroke Volume = 50 mL

Cardiac Output=Heartbeats per minute X Stroke Volume

= 72 beats per minute X 50 ml

= 3600 ml

Action mentioned in Statements 1 and 2 are synchronous. As when Atria receive blood from all parts of the body which subsequently flows to ventricles action potential is generated at sino-atrial node passes from atria to ventricles both these actions occur together.

Blood is a connective tissue containing Fluid Matrix, Cells and Plasma. The blood component which is viscous and straw coloured fluid is Plasma which makes up 55 % of the blood.

Composition of Plasma:

1. Water- 92 %

2. Proteins -8 %

3. Glucose

4. Amino Acid, Vitamins, Urea, Hormone and Antibodies.

Function:

1. Proteins present in plasma helps in blood clotting.

2. Transportation of substances through blood.

3. It maintains the blood volume.

4. It maintains the electrolyte balance.

a. Plasma without blood clotting factors is called serum.

Explanation: Serum is a clear fluid devoid of clotting factors made through centrifugation.

b. Neutrophils and monocytes are phagocytic cells.

Explanation:

Neutrophils are phagocytotic. Whenever an infection occurs these cells are the first ones to reach the site and engulf the microbes.

Monocytes are phogocytotic and are known as White Blood Cells(WBC’S).Whenever an infection occurs these cells get activated and start attacking the germs. These cells engulf cancer cells, damaged and dead cells.

c. Eosinophils are associated with allergic reactions.

Explanation: Eosinophils promote inflammation and generate symptoms related to allergy as in Asthma, Hay fever, Pollen allergies etc.

d. Calcium ions play a significant role in clotting.

Explanation: When the injured tissues and platelets release Thromboplastin, initiation of enzyme prothrombinase takes place. Prothrombin in the presence of Calcium ions converts plasma protein Prothrombin to Thrombin. Now, Thrombin converts fibrinogen to fibrin. This fibrin helps in formation of clot by aggregating platelets, blood cells and plasma.

e. One can determine the heart beat rate by counting the number of ORS complex in an ECG.

In a normal ECG following waves are present:

1.P Wave : It represents Atrial Depolarisation

2.QRS Wave : It represents Ventricular Depolarisation

3.T Wave :It represents Ventricular Repolarisation.

4.U wave :It represents repolarisation of Purkinje Fibre. It is generally not seen in an ECG as it is very small.

The vascular connection that exists between the digestive tract and liver is known as Hepatic Portal System. The hepatic portal system directs deoxygenated blood from the parts of gastrointestinal tract to the liver and finally taking it to the heart.

HEPATIC PORTAL SYSTEM

a. The disorder caused due to acute chest pain due to failure of O2 supply to heart muscles is known as ANGINA PECTORIS. It is caused when adequate oxygen does not reach the heart muscles leading to heart pain and discomfort.

b. Increased systolic pressure causes HYPERTENSION. It mainly occurs when the blood pressure constantly remains higher than normal which is 120/80 mm Hg.

Due to narrowing of the lumen of arteries Atherosclerosis takes place. Atherosclerosis is the condition in which build-up of cholesterol, fats takes place in the wall of the artery. This causes decreased size of the lumen hence decreased flow of blood towards the heart.

Symptoms:

1. Pain in chest

2. Fatigue

3. Shortness of breath

4. Angina

Treatment:

1. It includes prescribing statins to lower cholesterol thereby reducing the cholesterol build up on the walls of arteries.

2. Surgery is also required in some cases. Surgical procedures like angioplasty or bypass are done.

ATHEROSCLEROSIS

a. Purkinje fibre: It is present in the Myocardium of the ventricle and is formed by the branching of bundle of his.

Function:It carries impulses from the Sino Atrial Node (S.A. node).

b. Bundle of His:These are fibres which originates from the AV node present in the wall of right atrium.

Function:It transfers electrical impulses from the AV node to the ventricles of the heart.

LOCATION OF PURKINJE FIBRES & BUNDLE OF HIS

Erythroblastosis foetalis occurs due to Rh incompatibility between the mother and the foetus during pregnancy which may lead to death of the foetus or severe Anaemia.

If blood clotting does not take place excessive bleeding would take place which might lead to death.

Time gap in the passage of action potential from sino-atrial node to the ventricle allows ventricles to relax. This causes ventricular pressure to fall leading to the closure of semilunar valves which prevents the backflow of blood into the ventricles.

In an ECG, QRS complex represents ventricular depolarisation. Normal duration of QRS complex is less than or equal to 0.10 seconds. If QRS complex is longer than 0.10 seconds and the wave is enlarged it indicates the person is having Myocardial Infarction or Heart Attack.

1. The walls of ventricles are much thicker than atria because, ventricles have to exert more pressure as it pumps out blood to all organs of the body. Atria receives blood so they have less load to take, hence thinner walls.

2. Right ventricle receives oxygenated blood from the lungs than pumps this blood to the left ventricle.

3.In turn left ventricle pumps oxygenated blood to all parts of the body.

a.

b.

c.

a. Anaemia:It is a disorder that occurs due to decreased number of RBC’s or lesser amount of haemoglobin than the normal value.It might be caused due to excessive loss of blood, destruction of RBC’s etc.

b. Angina Pectoris: It is caused when adequate oxygen does not reach the heart muscles leading to chest pain and discomfort.

c. Atherosclerosis: It is the condition in which build-up of cholesterol, fats takes place in the wall of the artery. This causes decreased size of the lumen hence decreased flow of blood towards the heart takes place. It is also known as Coronary Artery Disease.

d. Hypertension: It is the condition in which there is a constant increase in the normal blood pressure, which is 120/80 mm Hg. It affects all the vital organs like heart, kidney and brain etc. Blood pressure equal to or above 140/90 mm Hg is considered hypertension. It may be caused due to stress, high sodium intake or heart related problems.

e. Heart failure: It is the condition in which heart is unable to pump enough blood to meet the body’s requirement. It’s main symptom is congestion of the lungs. It may occur due to weakening of the heart muscles or due to any other defects.

f. Erythroblastosis foetal is : In this condition there is a destruction of foetal RBC’s due to an incompatibility between the mother and foetus’s Rh factor or Rhseus Monkey factor. This may lead to death or severe Anaemia of the foetus

1. Birds and mammals have four chambered heart. Which are two atria and two ventricles.

2. The two atria are separated by inter-atrial septum and the two ventricles are separated by inter-ventricular septum.

3. Oxygenated blood received by the left atria passes to the left ventricle and Deoxygenated blood received by the right atria passes to the right ventricle without getting mixed

4. The blood is circulated to the body organs through the systemic circulation and to the lungs through Pulmonary circulation.

5. This shows that birds and mammals have two separate circulatory pathways which are Systemic and Pulmonary Pathway

Advantage of Double Circulation:

1. Deoxygenated and oxygenated blood remains separated and do not mix.

The vascular connection that exists between the digestive tract and liver is known as Hepatic Portal System.The hepatic portal system directs deoxygenated blood from the parts of gastrointestinal tract to the liver and finally taking it to the heart.

Significance:

1. It provides liver with metabolic substrates.

2. It ensures that substances are first processed by liver before reaching systemic circulation.

Lymphatic system is a network of vessels which passes through all organs to allow the movement of a fluid called lymph.

Main organs of Lymphatic System are:

1. Thymus

2. Spleen

3. Appendix

4. Tonsils

Functional significance of lymphatic system:

1. The fluid lymph carries hormones and nutrients.

2. It maintains fluid balance between blood and tissues also known as fluid haemostasis.

3. Fat absorption takes place through lymph.

4. It renews Extra Cellular Fluid (ECF).

5. Maturation of B and T lymphocytes take place with the help pf lymph.

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b.

c.

1. Thrombocytes are also known as Platelets and are found in blood.

2. They are formed in the bone marrow.

3. When an injury occurs, bleeding starts taking place.

4. This causes platelets to disintegrate and start releasing Clotting Factor III, also known as Thromboplastin.

5. Thromboplastin in the presence of calcium ions activate Prothrombokinase. Which further leads to a series of reactions causing blood clot.

a. In early embryonic stage RBC’s are produced in: Yolk Sac

In later embryonic stage RBC’s are produced in : Liver and Spleen

In mature adults RBC’s are produced in : Bone Marrow

b. Part of heart which is responsible for initiating and maintaining its rhythmic activity is SA node or Sino Atrial Node because of which it is also known as Pacemaker of the heart.

c. Reptilians have a three chambered heart (2 atria and 1 ventricle) whereas crocodiles have four chambered heart (2 atria and 2 ventricles) in which the mixing of oxygenated and deoxygenated blood does not take place.

1. There are four types of blood group A,B,O and AB.

2. There is one other type of blood group known as Rh factor or Rhesus Monkey factor which is an inherited factor.

3. Most of the people are Rh positive (Rh+ve) which means that the person have Rh factor in them.

4. People who do not have Rh factor are called as Rh negative people (Rh-ve).

5. Rh-incompatibility in humans may lead to a disorder called as Erythroblastosis foetalis.

6. In this disorder, at the time of pregnancy if the foetus is Rh+ve and the mother is Rh-ve and if the blood from foetus enters the mother’s bloodstream, antibodies against the foetus blood is created.

7. At the time of first pregnancy it does not have any affect.

8. But in subsequent pregnancies if the baby is (Rh+ve), the antibodies formed against Rh+ve blood during first pregnancy may enter the foetus through placenta.

9. This may lead to destruction of foetus’s RBC’s which may lead to death of the foetus or extreme Anaemia.

Cardiac cycle is the cycle of initiation of a beat till the beginning of another heartbeat.

Events of a Cardiac Cycle:

1. Atrial Systole (0.7 sec): In this event atria contracts due to the wave of contraction initiated by the SA node.

2. Now, the blood is forced into the ventricles as the bicuspid and tricuspid valves are open.

3. Ventricle Systole (0.5 sec): After this, contraction of ventricles start taking place due to the wave of contraction initiated by the AV node.

4. This leads to the closing of bicuspid and tricuspid valve and the first heart sound is produced ‘lub’.

5. Complete Ventricular Systole: After ventricular contraction the blood flows into the pulmonary trunk and aorta as the semilunar valves are opened.

6. Ventricular Daistole : In this event the ventricles relax and the semilunar valves close and the second heart sound is made ‘dub’.

7. Complete Ventricular Diastole: The opening of bicuspid and tricuspid valves take place as the pressure of ventricles lowers down and blood flows from atria to the ventricles.

8. The duration of this cycle is about 0.8 seconds.

CARDIAC CYCLE

Double Circulation:

1.Birds and mammals have four chambered heart which are two atria and two ventricles.

2.The two atria are separated by inter-atrial septum and the two ventricles are separated by inter-ventricular septum.

3.Oxygenated blood received by the left atria passes to the left ventricle and Deoxygenated blood received by the right atria passes to the right ventricle without getting mixed

4.The blood is circulated to the body organs through the systemic circulation and to the lungs through Pulmonary circulation.

5.This shows that birds and mammals have two separate circulatory pathways which are Systemic and Pulmonary Pathway

Advantage of Double Circulation:

1. Deoxygenated and oxygenated blood remains separated and do not mix.

DOUBLE CIRCULATION

1. There are two types of blood grouping which are ABO and Rh.

2. ABO grouping is based on the presence or absence of two antigens on the RBC’s which are A and B.

3. These are three alleles I^A,I^B andI ^O.

4. Gene I^A I^A or I^A I^O Codes for blood group A

5. Gene I^BI^B or I^BI^O Codes for blood group B.

6. Gene I^OI^O Codes for blood group O.

7. Gene I^AI^B Codes for blood group AB.

8. People with blood group A, have antigen A on the surface of the RBC’s and produce antibodies against blood group B.

9. People with blood group B have antigen B on the surface of the RBC’s and produce antibodies against blood group A.

10.People with blood group AB have antigen A and B on the surface of the RBC’s and produce no antibodies.

11.People with blood group O have no antigens on the surface of RBC’s and produce antibodies against both A and B blood group.

13. This shows that blood group AB is a universal recipient and blood group O is a universal donor.

a. Hypertension: It is the condition in which there is a constant increase in the normal blood pressure(120/80mm Hg).It affects all the vital organs like heart, kidney and brain etc. Blood pressure equal to or above 140/90 mm Hg is considered hypertension.

Types of Hypertension:

1. Primary Hypertension: It is also known as Idiopathic Hypertension because the specific cause of the increased blood pressure is not known.

2. Secondary Hypertension: It is the type of hypertension with a known cause.

Risk Factors:

1. Alcohol

2. Diabetes

3. Obesity

4. Smoking

5. Excessive Sodium Intake

Prevention:

1. Increased intake of water.

2. Decreased intake of sodium or table salt.

3. Stress and Caffeine should be avoided.

b. Coronary Artery Disease: Narrowing of the arterial lumen due to the build up of fats and cholesterol which decreases the supply of oxygen to the body organs. It may also lead to the damaging of heart muscles.

Risk Factors:

1. Obesity

2.Smoking

3.Excess fat intake

4.Hereditary

Prevention:

1. Regular exercise

2. Eating healthy

3. Vitamin supplement

4. Aspirins or blood thinners

1. SAN: It is also known as Sino Atrial Node. It is present in the right atrium near the opening of superior Vena Cava. It is also known as Pacemaker because electrical impulse initiates from this part of the heart.

2. AVN: It is also known as Atrio Ventricular Node. It is present in the right atrium near the base of the inter atrial septum. It is also known as Pacesetter. It causes a delay between the atrial and ventricular excitation. This delay ensures that the blood is completely pumped into the ventricles by the atria before the ventricles contract.

3. Bundle of His: It is a part of the electrical conduction system. It transmits impulses received from the AV node to ventricles.

4. Purkinje Fibres: The branching of bundle of His give rise to small fibres known as Purkinje fibres. These fibres transmit impulse to the ventricular muscles.