GENERAL INTRODUCTION-

  • Body Fluids– Body fluids is medium of transport of substance in body. It has 2 types-
    • Blood,
    • Lymph.

BLOOD-

Blood is connective tissue which contain plasma, formed elements and fluid matrix.

  • Plasma(55% present in blood)-
    • It is straw colored and viscous fluid.
    • Plasma contain 90%-92% water, 6%-8% proteins (Fibrinogen-required for blood clotting, globulin– help in defense of body, albumins– help in osmotic balance) and some minerals like Na+, Ca++, Mg++, glucose, amino acids, lipids etc.
    • Serum– When plasma have without factor of clotting.
  • Formed Elements(45% present in blood)–
    • Erythrocytes, leucocytes and platelets are called formed elements.
      • Erythrocytes(or WBCs)-
        • WBCs are most abundant present in cells.
        • About 5-5.5 millions of RBCs are present in mm-3 of blood in average healthy man.
        • In adult, RBCs formed in red bone marrow.
        • RBCs lack of nucleus and biconcave in shape.
        • RBCs contain iron rich protein pigment called hemoglobin(due to presence of hemoglobin, blood is red).
        • There are 12-16 grams of hemoglobin present in 100 ml blood in healthy person.
        • RBCs molecule play important role in transport of respiratory gases.
        • Average life span of RBCs is 120 days, then they destroy in graveyard of RBCs(RBCs ka kabristaan).
        • Leucocytes(or WBCs)-
          • It has lack of hemoglobin, since they are white or colorless fluid.
          • WBCs contain nucleus.
          • There are 6000-8000 RBCs are present in mm-3 of blood.
          • Life span of WBCs are very lesser than RBCs.
          • Leucocytes have 2 main categories-
            • Granulocytes- Neutrophils(most abundant, about 60-65% of total WBCs), eosinophils and basophils(most least, about 0.5-1% in total WBCs) are types of granulocytes.
            • Agranulocytes- Lymphocytes(20-25% in total WBCs) and monocytes are types of agranulocytes.
              • Neutrophils and monocytes(about 6-8%) are phagocytic cell(destroy outer organisms enter in body).
              • Basophils secrete histamine, serotonin, heparin, etc. involve in inflammatory reaction.
              • Eosinophils(2-3%) protect form infection and allergic reactions.
              • Lymphocytes have 2 types- ‘B’ and ‘T’. Both are responsible for immune response of body.
  • Platelets(or Thrombocytes)-
    • They produced form megakaryocytes(special cell in bone marrow).
    • Blood contain 1,50,000-3,50,000 platelets mm-3 in healthy person.
    • Platelets also involved in coagulation of blood.
    • If their number is decrease, then clotting disorder, which cause loss of blood.

BLOOD GROUPS-

  • There are 2 type of grouping in human body- ABO grouping and Rh grouping.
  1. ABO grouping–
  • It is based on present or absent of antigen (antigen present on surface of RBCs). These antigens are A and B.
  • The plasma of different individuals contain 2 natural antibodies (protein produced based on response of antigens).
  • The antigens and antibodies are distributed into 4 groups- A, B, AB and O.
  • During blood transfusion (transfer of blood form one person to another), only match blood can be transfer. First, carefully check the blood group of donor (who donate his blood) and recipient (who receive donor ‘s blood) are matched or not, if match, blood able to transfer otherwise not.
  • The blood groups and donor compatibility are-
Blood GroupAntigens on RBCsAntibodies in PlasmaDonor ‘s Group
AAanti-BA, O
BBanti-AB, O
ABA, BnilA, B, AB, O
Onilanti- A, B       O

2. Rh grouping–

  • The antigen Rh means Rhesus(or Rh).
  • It is present on surface of RBCs(present in 80% in humans).
  • Rh positive(Rh+ve)- Blood has the Rh antigen on RBCs.
  • Rh negative(Rh–ve)- Blood does not have the Rh antigen on RBCs.
  • If the Rh negative person expose Rh positive, then specific antibodies formed against the Rh antigen. So Rh blood group also match before blood transfusion.
  • In case of pregnant mother, we seen the Rh incompatibility(or mismatching). We observed that the Rh negative blood of pregnant mother with Rh positive blood of foetus. Then the Rh antigen of foetus not expose by Rh negative blood of mother during her first pregnancy because both two blood separated by placenta. During delivery, have possibility that some amount of maternal blood come in baby.
  • In some cases, mother start to preparing the antibodies against Rh antigen in her blood.
  • In case of subsequent pregnancies, the Rh antibodies from mother can leak into blood of foetus (Rh+ve) and destroy the foetal RBCs. It may be harmful for foetus or may me cause severe anaemia and jaundice(peelia) to baby. This condition called erythroblastosis foetalis. This can be avoid by administering anti-Rh antibodies to the mother immediately after delivery of first child.

COAGULATION OF BLOOD(OR BLOOD CLOTTING)–

  • Coagulation (blood clotting) is the process where blood stops flowing from a wound after an injury, preventing excessive blood loss.
  • A clot forms at the injury site, made of fibrins, which are formed by converting fibrinogen (inactive protein) in blood plasma into fibrins using the enzyme thrombin. Prothrombin, another inactive substance in plasma, is converted into thrombin.
  • Thrombokinase, an enzyme complex, triggers this process through a cascade reaction involving various inactive factors in the blood.
  • Platelets and tissue factors at the injury site activate coagulation, and calcium ions are crucial for the clotting process.

Lymph (Tissue Fluid):

  • As blood passes through capillaries, water and small substances move out, creating interstitial fluid. This fluid exchanges nutrients and gases between blood and cells.
  • The fluid is collected by the lymphatic system and returned to veins. This fluid is called lymph.
  • Lymph is colorless, contains immune cells called lymphocytes, and carries nutrients, hormones, and fats (absorbed through the lacteals in the intestines).

Circulatory Pathways:

  • Open circulatory system (found in arthropods and molluscs) has blood flowing through large vessels into body cavities (sinuses).
  • Closed circulatory system (in annelids and vertebrates) has blood confined to vessels for precise control of flow.
  • Human heart:
    • Fishes: 2-chambered heart (1 atrium, 1 ventricle) pumps deoxygenated blood.
    • Amphibians/Reptiles: 3-chambered heart with 2 atria and 1 ventricle (mixed blood).
    • Crocodiles/Birds/Mammals: 4-chambered heart (2 atria, 2 ventricles) with separate circulations for oxygenated and deoxygenated blood.

Human Circulatory System:

  • The heart is in the thoracic cavity between the lungs, protected by the pericardium.
  • The heart has four chambers: 2 atria (upper) and 2 ventricles (lower).
  • The right atrium connects to the right ventricle through the tricuspid valve, and the left atrium connects to the left ventricle through the bicuspid valve.
  • Blood moves through the heart in one direction due to valves that prevent backflow.
  • The sino-atrial node (SAN), located in the right atrium, initiates the heart’s rhythmic contractions (acting as the pacemaker).

Cardiac Cycle:

  • Diastole: All chambers relax, allowing blood to flow into the ventricles.
  • Systole: The atria contract, pushing blood into the ventricles, which then contract to pump blood out to the lungs and the rest of the body.
  • The heart’s pumping cycle consists of both atrial and ventricular contractions and relaxations.
  • A cardiac cycle lasts 0.8 seconds, with each ventricle pumping about 70 mL of blood (stroke volume).
  • Cardiac output is the total blood pumped per minute (stroke volume × heart rate) and is about 5 liters per minute.
  • Heart sounds:
    • Lub: closure of atrioventricular valves.
    • Dub: closure of semilunar valves.

Electrocardiograph (ECG):

  • An ECG records the electrical activity of the heart, showing the P-wave (atria depolarize), QRS complex (ventricles depolarize), and T-wave (ventricles repolarize).
  • The ECG helps diagnose heart conditions based on abnormal wave patterns.

Double Circulation:

  • Pulmonary circulation: Deoxygenated blood from the right ventricle goes to the lungs to receive oxygen, then returns oxygenated blood to the left atrium.
  • Systemic circulation: Oxygenated blood from the left ventricle flows through the body, and deoxygenated blood returns to the right atrium.
  • The body has a hepatic portal system (blood from the digestive system to the liver) and a coronary system (for blood supply to the heart muscle).

Regulation of Cardiac Activity:

  • The heart is auto-regulated by specialized tissue (nodal tissue) but can be influenced by the autonomic nervous system (ANS):
    • Sympathetic nerves increase heart rate and force.
    • Parasympathetic nerves decrease heart rate.
    • Adrenal hormones can also increase heart rate.

Disorders of the Circulatory System:

  • Hypertension: High blood pressure can lead to heart disease and damage vital organs.
  • Coronary Artery Disease (CAD): A condition where arteries supplying the heart are narrowed due to fatty deposits.
  • Angina: Chest pain due to insufficient oxygen supply to the heart muscle.
  • Heart Failure: A condition where the heart is unable to pump blood effectively.

Summary:

  • Blood circulates through a closed system to transport nutrients, oxygen, and waste products.
  • The heart, composed of four chambers, pumps blood in a double circulation system—pulmonary (to lungs) and systemic (to the body).
  • The cardiac cycle involves the contraction and relaxation of heart chambers and generates heartbeats.
  • The heart’s electrical activity is monitored by an ECG, and it maintains rhythmic activity through the SA node (pacemaker).
  • Blood pressure and circulation are regulated by neural and hormonal signals, but disorders like hypertension, CAD, and heart failure can cause serious health issues.

These all are the notes of chapter 15. And important questions are below HERE. *#THANKS FOR VISITING, VISIT AGAIN#* 😊

1. What are body fluids, and what types are there?

  • Answer: Body fluids are substances that transport various materials throughout the body. The two main types are blood and lymph.

2. What is blood, and what does it contain?

  • Answer: Blood is a connective tissue that contains plasma, formed elements, and a fluid matrix. Plasma makes up 55% of blood and is made up of water, proteins, and minerals. The formed elements, which make up 45% of blood, include red blood cells (RBCs), white blood cells (WBCs), and platelets.

3. What is plasma made of?

  • Answer: Plasma is a yellowish fluid that is 90-92% water and contains proteins like albumins (for osmotic balance), globulins (for defense), and fibrinogen (for clotting). It also contains minerals such as Na+, Ca++, and glucose.

4. What are erythrocytes (RBCs)?

  • Answer: RBCs are red blood cells that are biconcave in shape and lack a nucleus. They are packed with hemoglobin, a protein that helps transport oxygen. RBCs live for about 120 days before being destroyed in the spleen.

5. What are leukocytes (WBCs)?

  • Answer: WBCs are white blood cells that protect the body from infection. They have a nucleus and come in two types:
    • Granulocytes: Neutrophils, eosinophils, and basophils.
    • Agranulocytes: Lymphocytes (involved in immune response) and monocytes (phagocytic).

6. What are platelets, and what is their function?

  • Answer: Platelets, or thrombocytes, are small cells that help in blood clotting. They are produced from megakaryocytes in the bone marrow and prevent excessive blood loss from injuries.

7. What are blood groups?

  • Answer: Blood groups are based on antigens present on the surface of RBCs. The ABO system classifies blood into four types: A, B, AB, and O. Rh factor refers to the presence (Rh+) or absence (Rh-) of the Rh antigen.

8. Why is matching blood groups important during blood transfusion?

  • Answer: During a blood transfusion, it is important to match the donor’s and recipient’s blood types to avoid an immune reaction. Mismatched blood transfusion can lead to serious complications.

9. What is the Rh factor, and why is it important?

  • Answer: The Rh factor is an antigen present on RBCs. If an Rh-negative person is exposed to Rh-positive blood, their immune system can produce antibodies, which is especially dangerous during pregnancy if the mother is Rh-negative and the baby is Rh-positive.

10. What is blood clotting (coagulation)?

  • Answer: Blood clotting is the process of stopping bleeding after an injury. It involves the transformation of fibrinogen into fibrin, forming a clot. This process is triggered by enzymes like thrombokinase, and calcium ions are essential for clot formation.

11. What is lymph?

  • Answer: Lymph is the fluid that is collected from the tissues after blood passes through the capillaries. It is colorless and contains lymphocytes, nutrients, hormones, and fats.

12. What are the types of circulatory systems in animals?

  • Answer: There are two types of circulatory systems:
    • Open circulatory system: Found in arthropods and molluscs, where blood flows into body cavities.
    • Closed circulatory system: Found in humans and vertebrates, where blood is confined to vessels.

13. What is the structure of the human heart?

  • Answer: The human heart has four chambers: two atria (upper chambers) and two ventricles (lower chambers). The right side pumps deoxygenated blood to the lungs, while the left side pumps oxygenated blood to the body.

14. What is the cardiac cycle?

  • Answer: The cardiac cycle consists of two phases:
    • Diastole: The heart relaxes, and blood fills the chambers.
    • Systole: The heart contracts, pumping blood out of the heart to the lungs and the rest of the body.

15. What is an ECG (Electrocardiograph)?

  • Answer: An ECG records the electrical activity of the heart. It shows the P-wave (atrial depolarization), QRS complex (ventricular depolarization), and T-wave (ventricular repolarization).

16. What is double circulation in humans?

  • Answer: Double circulation means that blood circulates through the heart twice:
    • Pulmonary circulation: Deoxygenated blood from the right ventricle goes to the lungs to receive oxygen.
    • Systemic circulation: Oxygenated blood from the left ventricle flows to the body.

17. How is cardiac activity regulated?

  • Answer: The heart’s activity is controlled by the sino-atrial node (SAN), which acts as the pacemaker. It can be influenced by the autonomic nervous system, where sympathetic nerves increase heart rate and parasympathetic nerves decrease it.

18. What are common circulatory disorders?

  • Answer: Some circulatory disorders include:
    • Hypertension: High blood pressure that can damage organs.
    • Coronary artery disease (CAD): Narrowing of the heart’s blood vessels.
    • Angina: Chest pain due to reduced oxygen supply to the heart.
    • Heart failure: The heart is unable to pump enough blood.

Summary:

  • Blood is a vital fluid for transport in the body. It consists of plasma, RBCs, WBCs, and platelets.
  • Blood groups are important for transfusions, and the Rh factor is crucial for pregnancy.
  • The heart pumps blood in a cycle to transport oxygen and nutrients, and its activity is regulated by electrical signals.
  • Lymph carries nutrients and immune cells, playing a crucial role in the body’s defense.