Draw a standard ECG and explain the different segments in it.
ECG is graphic record of the electric current produced by the excitation of the cardiac muscles. The instrument used to record the changes is an electrocardiograph. A normal electrogram (ECG) is composed of a P wave, a QRS wave (complex) and a T wave. The P Wave is a small upward wave that represents electrical excitation or the atrial depolarisation which leads to contraction of both the atria (atrial contraction). It is caused by the activation of SA node. The impulses of contraction start from the SAnode and spread throughout the artia.
The QRS Wave (complex) represents ventricular depolarisation (ventricular contraction). It is caused by the impulses of the contraction from AV node through the bundle of His and Purkinje fibres and the contraction of the ventricular muscles. Thus this wave is due to the spread of electrical impulse through the ventricles.
The T Wave represents ventricular repolarisation (ventricular relaxation). The potential generated by the recovery of the ventricle from the depolarisation state is called the repolarisation wave. The end of the T-wave marks the end of systole.
ECG gives accurate information about the heart. Therefore, ECG is of great diagnostic value in cardiac diseases.
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
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.
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