Gopal Jadhav

 1) Cerebrum is the largest part of the brain. It  forms 80-85% volume of the brain. 2) A median longitudinal fissure divides the cerebrum into two cerebral hemispheres. These hemispheres are interconnected by a thick band of transverse nerve fibres called corpus callosum. 3 3) The outer part of cerebrum is called cerebral cortex while the inner part is called cerebral medulla. 4) The roof of cerebrum is called pallium. Pallium is highly folded forming sulci and gyri.  Sulci are depressions while gyri are ridges. The gyri increase the surface area of cerebral cortex. 5 The ventro-lateral walls of cerebrum are thickened and are called corpora striata. 6) The cerebral cortex has three deep sulci, the central, lateral and parieto-occipital. 7) these sulci divide the cerebral hemisphere into four lobes. these are frontal, parietal, occipital and temporal lobes. A fifth median lobe called insula or insular cortex is folded deep within the laterral sulcus. 8) The central sulcus...

  Conducting system of myogenic human heart consists of sinoatrial node, atrioventricular node, bundles of His and Purkinje's fibre system. The pacemaker of the heart is sinoatrial node because here the heartbeat originates. Pacemaker has power of generation of wave of contraction. this is modified cardiac tissue, also called a nodal  tissue. SA node is situated in the wall of right atrium near the opening of superior vena cava. the wave of contraction generated by SA node is conducted by cardiac muscle fibres to both the atria. This results in contraction resulting into atrial systole. The atrioventricular node ( AV node ) is located in the wall of right atrium near the opening of coronary sinus .AV node receives the wave of contraction generated by SA node through internodal pathways. Bundle of His arises from AV node and divides into right and left bundle branches. These are located in the interventricular septum. The  bundle branches further form Purkinje fibres which...