Describe the evolutionary change in the pattern of heart among the vertebrates.
Vertebrates have a single heart. It is a hollow, muscular organ composed of cardiac muscle fibres. Two types of chambers in heart are atria and ventricles. The heart of lower vertebrates have additional chambers, namely sinus venosus and conus arteriosus or bulbus arteriosus or truncus arteriosus. During the course of development, in higher vertebrates, the persistent portions viz, auricles and ventricles are retained. However, these get complicated by incorporating several valves inside them and becoming compartmentali sed.
In fishes, heart is two chambered (1 auricle and 1 ventricle). Both the accessory chambers, sinus venosus and conus arteriosus are present. The heart pumps out deoxygenated blood which is oxygenated by the gills and sent to the body parts from where deoxygenated blood is carried to the heart. It is called single circulation and heart is called venous heart. Lung fish, amphibians and reptiles have three chambered heart, (2 auricles and 1 ventricle). The left atrium gets oxygenated blood from the gills/lungs/skin/buccopharyngeal cavity and the right atrium receives the deoxygenated blood from other body parts. But both oxygenated and deoxygenated blood get mixed up in single ventricle which pumps out mixed blood. This is called incomplete double circulation.
Crocodiles, birds and mammals have a complete four chambered heart (right and left auricles; right and left ventricles). Oxygenated and deoxygenated blood never get mixed. Right parts of the heart receive deoxygenated blood from all other body parts and send it to lungs for oxygenation whereas left parts of heart receive oxygenated blood from lungs and send it to other body parts. This mode of circulation is termed as complete double circulation which includes systemic and pulmonary circulation. There are no accessory chambers in heart of birds and mammals.
State the functions of the following in blood
(a) Fibrinogen
(b) Globulin
(c) Neutrophils
(d) Lymphocytes
Complete the missing word in the statement given below:
(a) Plasma without_______factors is called serum.
(b) _______and monocytes are phagocytic cells.
(c) Eosinophils are associated with reactions.
(d)_______ions play a significant role in clotting.
(e) One can determine the heart beat rate by counting the number of_______in an ECG.
Given below are the abnormal conditions related to blood circulation. Name the disorders.
(a) Acute chest pain due to failure of 02 supply to heart muscles
(b) Increased systolic pressure
Match Column I with Column II.
Column I Column II
(a) Eosinophils (i) Coagulation
(b) RBC (ii) Universal recipient
(c) AB Group (iii) Resist infections
(d) Platelets (iv) Contraction of heart
(e) Systol (v) Gas transport
Answer the following:
(a) Name the major formed. Which part of heart is responsible for initiating and maintaining its rhythmic activity? What is specific in the heart of crocodiles among reptilians?
Explain the advantage of the complete partition of ventricle among birds and mammals and hence leading to double circulation.
Briefly describe the following:
(a) Anaemia
(b) Angina pectoris
(c) Atherosclerosis
(d) Hypertension
(e) Heart failure
(f) Erythroblastosis foetalis
What is the significance of atrio-ventricular node and atrio-ventricular bundle in the functioning of heart?
How will you interpret an electrocardiogram (ECG) in which time taken in QRS complex is higher?
Name the components of the formed elements in the blood and mention one major function of each of them.
Define the following terms and give their location.
(a) Purkinje fibre
(b) Bundle of His
In the diagrammatic presentation of heart given below, mark and label, SAN, AVN, bundle of His and Purkinje fibres.
What is the significance of time gap in the passage of action potential from sino-atrial node to the ventricle?
Given below is the diagrammatic represen-tation of a standard ECG. Label its different peaks.
Write the differences between:
(a) Blood and lymph
(b) Open and closed system of circulation
(c) Systole and diastole
(d) P-wave and T-wave
Differentiate between
(a) Blood and lymph
(b) Basophils and Eosinophils
(c) Tricuspid and bicuspid valve
Write the features that distinguish between the two
(a) Plasma and Serum
(b) Open and closed circulatory system
(c) Sino-atrial node and Atrio-ventricular