RBSE Class 11 Biology Notes Chapter 18 Body Fluids and Circulation

These comprehensive RBSE Class 11 Biology Notes Chapter 18 Body Fluids and Circulation will give a brief overview of all the concepts.

RBSE Class 11 Biology Chapter 18 Notes Body Fluids and Circulation

→ Circulatory System: The system made of vessels, through which nutritive substances, gases hormones, waste materials and other products are transported throughout the body, called circulatory system.

→ Types of Circulatory system: Circulatory system is of two types:

• Open circulatory system: In this type of circulatory system, the blood does not flow in specific closed vessels. In this blood remains in contact with cells and tissues. Example: Arthropods and molluscs.
• Closed circulatory system: In this type of circulatory system blood and lymph flow in closed vessels. In this blood circulation from heart to body tissues and from body tissues to heart is restricted to these blood vessels only. Examples: Earthworm, rabbit, human being etc.

→ Part of blood: Blood is a fluid connective tissue which has two main parts:

1. plasma and
2. blood corpuscles.

 

→ Plasma: Plasma is a pale coloured, slightly alkaline, clear, transparent fluid. It is fluid part of blood having 90% of water and 10% organic and inorganic materials. 

→ Blood corpuscles: These form about 45% of the blood. Blood corpuscles are of the following three types:

1. Red blood corpuscles (RBCs) or erythrocytes,
2. White blood corpuscles (WBCs) or leucocytes and
3. Blood platelets or thrombocytes.

→ Blood groups: Human being has four types of blood groups: A, B, AB and O. They are based on antigen.

→ A person having blood group O, can donate blood to all blood groups, hence called universal donor. While a person having blood group AB can receive blood from all blood groups, hence called universal recepient.

→ Rh-factor: It is a specific antigen found on RBCs. The people having this antigen in their blood are called Rh⁺, while the people lacking this antigen are called Rh⁺.

→ Blood clotting: Whenever any injury or a cut on the body thereby bleeding gets start, this bleeding autometically stops with 3-6 minutes due to clot formation. It is called blood clotting. In this process, insoluble fibrinogen protein of blood converts into insoluble fibrin. Fibrin fibres form a network like structure on injury. In this network numerous blood corpuscles trapped to form blood clot and bleeding get stopped.

→ Haemolysis: The breaking and destroying of RBCs thereby haemoglobin oozing out into plasma, called haemolysis. Due to this a disease jaundice occurs in human beihgs.

→ Heart: It is a muscular, pumping organ, situated between both the lungs in thoracic cavity. It has three layers: epicardium, myocardium and endocardium.

→ Heart beat: The regular and rhythmic contraction of heart is called heart beat.

→ Cardiac cycle: The various events occuring in the heart from the end of the one heart beat to the end of the next one, constitute cardiac cycle. Each cardiac cycle has two phases: contraction phase or systole, and relaxation phase or diastole. The heart of an adult human being beats at a rate of 72 times per minute.

→ Control of heart beat: The wall of heart has two pace makers:

1. sinoatrial node (SA node) and
2. sinoventricular node (SV node).

Both of these pace makers control heart beat. The nerves ending to SA node increase heart beat and inhibitory nerves decrease heart beat.

→ Double circulation: The blood passes twice through the heart in its one complete circulation, it is called double blood circulation. All mammals have double blood circulation.
 
→ Arteries: These are thick walled vessels, carry blood from heart to body parts and ending into capillaries.

→ Veins: These are thin walled vessels, bring blood from body parts to the heart. These starts from capillaries.

→ Lymph: It is a transluscent, alkaline fluid found in lymph vessels and in between blood capillaries and tissues, it consists of plasma and leucocytes.

→ Lymphatic system: Lymphatic system is a fluid pickup system which works with closed circulatory system. It is found in the form of an extensive network of thin walled vessels.

→ Haematology: Study of blood.

→ Serology: Branch of biology deals with the study of serum.

→ Angiology: Study of blood circulation.

→ Antigen: Internal or foreign protein which induces the formation of antibodies.

→ Antibody: The structure formed against antigen.

→ Haemolysis: The process of destroying of RBCs.

→ Erythropoiesis: The process of the formation of RBCs.

→ Blood coagulation: The process of blood clot formation. ,

→ Anticoagulant: Factors which inhibit blood clotting, such as heparin.

→ Haemocytometer: The device used in counting of RBCs.

→ Systole: Contraction phase of heart.

→ Diastole: Relaxation phase of heart.

→ Cardiac cycle: Repeatation of heart beat.

→ Systemic circulation: The circulation of blood between heart and body organs.

→ Pulmonary circulation: The circulation of blood between heart and lungs.

→ Angina: Pain occurs due to lacks of O₂ in cardiac muscles.

→ Leucopenia: The number of WBCs is less than normal.

→ TechimardLa: Increase of heart beat rate.

→ Bradycardia: Decrease of heart beat rate.

→ Arrythemia: To be irregular of heart beat.

→ Leukemia: Cancer produced in situation of increasing WBCs.

→ Phagocytosis: The process of engulf solid material by the cell.

→ Homeostasis: The process to maintain internal environment of body constant.