Circulatory system: The circulatory system is that system which is related with the blood circulation in body.
The circulatory system contain following parts:
Blood: The blood is special fluid connective tissue which contains the plasma, RBC, WBC & platelets. The healthy person contains about 1/12th blood of the total body.
Blood composition: The blood contains about 55% plasma, 45% essential elements or formed elements, RBC, WBC & platelets.
Plasma: The 55% part of the blood is plasma. The plasma contains about 90% water and important plasma proteins; prothrombin + fibrinogens, globulin and albumin.
The plasma also contain the salts like sodium chloride, NaHCo3, Ca2+, Mg2+, Fe 2+ etc. It also contains the glucose, fats, urea, uric acid, cholesterol and amino acid etc.
The plasma also contains the gases like O2 and CO2.
It also contains the internal secretions, hormone and antigens.
The plasma without the clotting factor is called the serum.
Formed / Essential elements: It is 45% of the blood. It contains the RBC, WBC and platelets.
The normal hemoglobin value is 15gm per 100ml. The RBC provides the red color to the blood the cells are rounded or bi-concave disc like structure.
Type of WBC
The granulocytes are of three types
Eosinophils: These cells reduce the inflammatory reaction. These are anti-histaminic.
Basophiles: These cells secrets histamine and heparin.
Neutrophils: These cells kill the bacteria by phagocytosis (kill the bacteria). This is never ending function even in a healthy person.
Extra for knowledge:-
Jaundice: The Old RBCs are destroyed by the liver. It releases the hemoglobin. The global portion separates from the hemoglobin. This is a protein finally the heam breaks and produces the bilirubin pigments, the enzymes of liver mix with this pigment. These mixed pigment of bilirubin come in the intestine by the bile juice. In the intestine the bilirubin pigment is modified by bacterial enzymes which give the brown color to the feces (excreta) some pigments are absorbed by the blood vessels and enter in the blood circulator. It gives the yellowish urine. When there is excess of bilirubin pigment it causes the jaundice.
Test for jaundice – Serum bilirubin
Erythropoiesis: The development of erythrocytes is called erythropoiesis.
Formation of RBC in the fetal life: The formation of RBC during the fetal life takes place by the spleen, liver and after the birth this function is performed by bone narrow.
Factors affecting Erythropoiesis:
Antigen: It is a substance that produces the antibodies.
Antibodies: It is a substance capable of reacting with antigen.
Hemoglobin: It binds the CO to form carboxyl hemoglobin. Hemoglobin has high affinity for O2 & CO2 the pH value of the blood is 7.35-7.45. It is slightly alkaline.
Blood clotting: whenever there is some cut or injury the blood starts coming out. It sets into gel after sometime this is called as the blood clotting.
Factors affecting blood clotting.
1. Blood vessels coated by Vaseline / wax.
2. by Cold
3. It will be slow by the addition of potassium citrate or sodium citrate which removes the calcium salt.
Blood Groups: The blood groups are different chemically from person to person. When two different type of blood are mixed, the RBCS run together form a clamp. The clamping of RBCS is called agglutination.
The agglutination is due to the content of 2 types of proteins:-
These antigens and antibodies are present in the plasma. There are the antigens of two types.
In a person the RBC may contain only A or B or both A and B or neither A nor B and the plasma may contain ‘a’ or ‘b’ or both ‘ab’ or neither ‘a’ not ‘b’ antibodies.
The antigen A can mix with antibodies b and antigen B with antibody a.
Therefore every person contains two factors AB & ab on the basis of this.
There are four blood groups in the humans.
RH factor: It is a protein at surface of RBC in many persons 95-99% of person contains the RH positive factor and 1-5% is RH negative.
The blood group O is the universal donors and AB is universal acceptors / receptors.
Transfusion: The first transfusion of Rh positive blood to Rh negative person causes no harm because the Rh negative person develops the anti Rh factors or antibodies in his body. In 2nd person, the person’s anti RH factors attack and destroys the donors RBCs.
BOMBAY blood group: This is extremely rare ABO group called so because it uses first discovered among some people in Bombay though the group is more likely to occur in east Indians. It is a very rare group in Bombay also, it is not limited to east Indians but in Japanese also, this RBCs lack ABH antigens and the serum contains the ABH.
The heart is a hollow muscular organ roughly the size is 12cms from apex to base and 8cm from left to right and 6cm from front to back. The weight is approximately 300gms in the males and 260gms in females. It is reddish brown in color and conical in shape. It is situated almost in the middle of the thoracic cavity.
The broad base faces in the upward direction and open in the downward direction slightly to the left side, it rests on diaphragm. The heart is present in a protective covering pericardium. It has two layers inner and outer. The pericardial fluid is filled between the two layers. It gives protection to the heart during the heartbeat.
The organs related with the heart.
The heart is divided by septa into two equal parts right and left each half part contains the two collecting chambers the upper two are called as the auricles and the lower two are called as the ventricles the heart contains the four chambers.
Blood Supply to heart: The right and left coronary arteries divided into smaller arteries which encircle the heart and supply the blood to all parts of the organ heart. The return of blood is by the coronary veins which open by the coronary sinus in the right auricle just above the inferior vena cava this is called as the coronary circulation.
The normal blood flow is 250ml/min within the walls of the heart.
Nerve supply to heart- VAGUS nerve.
Internally the heart can be divided into two parts right and left part each part contain the two chambers the upper chambers are called as the auricles and the lower chambers are called as the ventricles. The right and left part are separated by the common wall intra auricular and intra ventricular septum.
The right auricle is connected with the right ventricles by a small pore called as the A-V aperture.
There is present a tricuspid valve which presents the back entry of the blood. The right auricle receives the superior and inferior vena cava which brings the blood from the upper and lower parts of the body. The walls of the auricles are thin because they pump the blood to the ventricles which are present just below them.
From the right ventricle arises the large blood vessel which is called as the pulmonary arch which takes the deoxygenated blood to the right and left lungs for purification. There is present the pulmonary value below the pulmonary arch (artery).
The left side of heart contains the oxygenated blood in the left auricles the oxygenated blood enters by the four pulmonary veins just below the left auricle there is present the left ventricle there also present the bicuspid valve, which presents the back flow of blood.
From the left ventricle arises the large blood vessel which is called as the aortic arch which supplies the oxygenated blood to the complete body except the lungs. There is present the aortic valve & the base of the aortic arch therefore these are four valves in the heart.
The wall of the left ventricles is approximately five times thicker than the right ventricle because it forces the blood to the further path of body from head to toe. The blood entering in the aortic arch from left ventricle has much more high blood pressure than the blood entering from right ventricle to pulmonary arch.
The length of the bicuspid valve mitral valve is about 3cms in diameter.
Tricuspid valve is 4cms in diameter.
The size of pulmonary valve is 2.5cm in diameter.
Aortic valve is 2.5cm in diameter
Coronary sinus: This is the largest venous channel about 2.3cms in length. This is present in the posteriors auricles ventricular groove called coronary sinus.
It opens into the right auricle in the lower part of inter auricular septum between the inferior vena cava and auricle ventricular opening.
Heart beat: The contraction and relaxation of the heart chambers to pump out and to receive the blood to the body and from the body is called heartbeat.
Blood Pressure: The pressure of flowing blood against the walls of the blood vessels.
Blood pressure is of two types:-
Cardiac output: It is the volume of blood send by both ventricles into the arterial system. In a normal resting person the heart beats about 72/min and pumps 70ml each time the amount of blood pumped each minute is about 5 liter/min. This is also called stroke volume.
Resting phase of heart: – The ventricular contraction is for 0.3 seconds. The relaxation period is longer= 0.5 sec. The resting phase for the heart is more it is 0.5 – 0.3 sec = 0.2 sec
Heart sound: is produced during the systolic and diastole blood pressure.
Blood circulation: The blood circulation takes place in the body as results of heart beat during the first phase. There is the relaxation of all the four chambers as a result of this the maximum oxygenated blood enter in the left auricle by these four pulmonary veins.
The maximum blood also enters from the superior and inferior vena cava (deoxygenated blood) in the right auricles Very little quantity of the blood also comes in the right and left ventricles through the A-V aperture.
During the phase two there is maximum contraction of the auricles as a result of this the maximum blood is forced in the ventricles which are also relaxed and are present just below the auricles.
During the phase three there is the maximum contraction of the ventricles as a result of this the auricles but due to the presence of bicuspid and tricuspid valve blood cannot go back but there is continuous pressure due to this the maximum blood from left ventricle passes in the aortic arch which supplies the oxygenated blood to the complete body parts, similarly the maximum blood enter in the pulmonary arch from the right ventricle and is taken to the lungs for purification.
When the oxygenated blood reaches the different parts of the body tissue as a result of the metabolism the O2 is used the energy are produced which is used by the body and the waste products like urea & CO2 are produced. The CO2 is takes by the superior and inferior vena cava to the right auricle of the heart from right auricle to right ventricle from right ventricle to the lungs by the pulmonary arch.
In the lungs as a result of respiration the air is purified the oxygenated blood is taken to the left auricle from left auricle to left ventricle then to aortic arch and then to the complete body in this way the blood circulation takes place.
The blood circulation between the lungs and the heart is called pulmonary circulation.
The circulation between heart and body tissue is called as the systemic circulation both these circulation make the total blood circulation which as the blood circulation in the body.
The conducting system is made up of this special myocardium which is responsible for initiation and conduction of cardiac impulse it contain following parts.
Properties of cardiac muscle:
Lead I– Right arm and Left arm
Lead II- Right arm and left leg
Lead III- Left arm and left leg
The connections over the chart with different electrodes are also used. The EGC recordings are designed by P, Q, R, S, and T. The wave P is due to the connection of the auricle. The waves Q, R, S are produced by the contraction of the ventricles. The wave T is produced by relaxation of the ventricles.
Pulse: The pulse may be defined as the wave of distention and elongation felt in an artery wall due to contraction of a left artery ventricle forcing about 60-80ml of blood into the already full aorta. The normal pulse at rest is about 60-80 per min.
Factors affecting the pulse rate:
Blood vessels: The blood vessels are the pathway or roots by which the blood travels or flows.
The blood vessels are of two types:
Difference between arteries or veins:
Transverse section of arteries and veins
Flow of the blood in the veins
When the blood flow is in the forward direction due to the forward pressure of the blood the valves of the vein opens and the blood flows in the forward direction when the blood tries to come back the valves does and no back flow of the blood is possible.
Blood Supply in upper limb: The sub-clavian artery arises from the aorta and passes over the first rib than near the clavicle. It enters the axilla where becomes the axillary artery.
At the lower boundary of the axilla it becomes the brachial artery which divided into radial and ulnar arteries. The radial artery passes down the radial side and the ulnar artery to the ulnar side.
Passing over the front of the wrist termination of these arteries from the deep and superficial palmar arch
Arteries of right upper limb
The superficial veins of upper arms begin as a network of small veins in the hands.
The blood collection is by these small veins into the median vein.
From the median vein they from the basilica vein, median cuboidal vein and cephalic veins.
The basilica vein continues as the axillary vein.
The cephalic vein runs up to the make a connection with the axillary vein.
Nerve Supply: The upper limbs are supplied by the different branches of brachial plexus which are axillary, ulnar, median, and radial dorsal scapular etc.
Superficial veins of right arm
Blood supply by the common carotid artery: This is the main artery supply the blood to the head and neck. There are two common carotid arteries the right and left.
The right common carotid artery originates from the branch cephalic trunk behind the sterno-clavicle joint in the neck.
The left common carotid artery arises in the thorax directly from the arch of aorta.
Each common caroled artery terminates between C3 and C4 (cervical) vertebra.
It gives the only two terminal branches.
Carotid artery Image
Axillary artery: This is the continuation of sub clavier artery and it extends from outer boarder of the first rib to lower body of the terse muscles then it continuous as brachial artery. It enters the axilla it is accompanied (along) with the axillary veins and brachial plexus in the axilla.
It is divided into three parts by pectorals major muscle:
Blood supply in the upper part of body:
Branches of left common artery:
Circle of Willis: This is the polygonal shaped anterior circle that is present in relation to the base of the brain at the level of inter peduncular fossa.
Formation: The circle is formed by branches of two internal carotid arteries and the two vertebral arteries.
Blood supply to lower limb: The right and the left common iliac artery supply the blood to the lower region. The internal iliac artery supplies the blood to the organs within the pelvic cavity in the females one of the largest braches is the uterine artery.
External iliac artery: It supplies the blood to the thigh to form the femoral artery.
Popliteal artery: It supplies the blood behind the knee.
Femoral artery: The upper part of the popliteal artery is called femoral artery.
Anterior tibial artery: It is present in the form of the leg and angle joint.
Dorsal pedic artery: it supplies the blood to the foot.
Plantar artery: It supplies the blood to sole.
Venous route from lower limb:
There are some deep and some superficial vein in the lower limb. The backward flow of the blood is presented by valves. The superficial veins get less support from the surrounding tissue then the deep veins.
The deep veins are as following:
Superficial veins are of two types:
Portal vein: Any vein of the body collects the blood from the different part of body and breakup in any other organ before reaching the heart is known as portal vein. For example: The hepatic portal vein- it collects the blood from the different parts like small intestine, Spleen and put the blood in the liver before reaching the heart this is called as the hepatic portal vein.
Arterial supply to foot: The foot is supplied by the planter arteries which are the branches of posterior tibias artery.
Branches of medial plantar artery
Venus drainage of foot: It is by the medial marginal vein, dorsal veins arch and lateral marginal veins.
Thrombosis: This is the intra vascular blood clot causing the thrombosis may be complete or in complete blocked of artery or vein.
Ascites and effusion: The ascites is the name given to the collection of excess of fluid in the peritoneal cavity. The most common cause are:
Cardiac failure: When the cardiac output is unable to maintain the blood circulation to meet with the sufficient need of the body. E.g. In exercise heart failure may involve either side of heart. Failure of one side results due to failure of other side.
Acute cardiac failure: A sudden reduced in output of blood from both ventricles causes the acute reduction in oxygen supply to all tissue. The death may occur due to anoxia of vital centers in the brain.
Shock: The shock occurs when the metabolic need have the cells are not met with because of the poor bleed supply. So there is the reduction or blood circulation in Blood pressure and cardiac output this causes the tissue hypoxia poor nutrition supply and collection of waste products.
Myocardial infarction: Infract means the death of the tissue due to the lack of the poor oxygen supply. In this condition the coronary artery is affected.
Angina pectoris: The increased cardiac output or the poor blood supply causes the angina pectoris.