Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Excitation of Heart - Circulation
The heart has an inherent capacity to contract rhythmically without any external stimulus. Proof of this is obtained when we see that the heart in a developing chick embryo begins to beat even before any nerve has reached it and also heart muscle cells grown in culture contract rhythmically without any external stimulus. The electrical activity begins in a pacemaker region of the heart. Pacemaker cells are capable of spontaneous activity and may be either neurous as in many invertebrate hearts or muscle cells. If the heartbeat is initiated in a neuron, the pacemaker is called neurogenic pacemaker and if the heartbeat is initiated in muscle cell then the pacemaker is known as myogenic pacemaker.
Based on the type of pacemaker, hearts are classified as neurogenic or myogenic. The contraction of mammalian heart begins in a small piece of embryonic type muscle located where the vena cava enters the right atrium. This is known as sinoatrial node (S-A node). The contraction spreads to the two atria, and after a slight delay to the atrioventricular node (A-V node). From here it spreads rapidly to the tip of the ventricles through special muscle fibres, from where it spreads more slowly up the walls of the ventricles. This arrangement allows the contraction to begin at the tip of the ventricles and to spread upwards to squeeze out blood in the most efficient way. It also ensures that both ventricles contract simultaneously.
mechanisms of reciprocal inhibition
Illustrate the types of Bone Remodeling Bone remodeling occurs on existing bone surfaces. However, unlike modeling, remodeling cannot cause large changes in bone structure at a
Define Vapor-pressure lowering and Osmotic pressure? 1. Vapor-pressure lowering: the decrease in the vapor pressure of a solution containing nonvolatile solutes, compared to th
Disaster management is aimed at minimizing or avoiding the potential losses from extreme events and assuring rapid and proper help to the affected people and ascertaining a quick a
MECHANISM OF GASTRULATION - It is most impotant stage of embryonal development, in which single layered blastula converts into 2 or 3 layered gastrula. During this stage,
Determine the Emerging clinical use of brain Emerging clinical uses include identifying brain regions from which epileptic seizures emanate and confirming diagnoses of neurodeg
Q. Does pH affect the enzyme activity? The concentrations of hydrogen ions in solution affect the enzyme activity. Each enzyme has utmost efficiency under an optimum p H . S
Q. Are protozoans presenting pulsatile or contractile vacuoles easily found in fresh or in salt water? Fresh water is the less concentrated of solutes than sea water and it fre
Q. What is Working Memory? Working Memory: It has often been suggested that memory does not always work in three stage sequence and the model of memory system comprising of sen
Define Requirements and Recommended Dietary Allowances (RDA)? What do we mean by requirements and RDA? The requirement level is the amount of nutrient needed to be absorbed to
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd