The conduction System1.pptx

The conduction System The Cardiovascular system Reminder: The structure of the heart RIGHT LEFT What is the conduction system? Study hint: You will only apply this KU if you see the word “conduction” on an exam question. Q. How does the heart beat? What is the conduction system? Q. How does the hear...

The conduction System The Cardiovascular system Reminder: The structure of the heart RIGHT LEFT What is the conduction system? Study hint: You will only apply this KU if you see the word “conduction” on an exam question. Q. How does the heart beat? What is the conduction system? Q. How does the heart beat? A. Electricity! Dev: The conduction system refers to the structures in the heart which create and transmit an electrical impulse, forcing the atria and the ventricles to contract. Key term: MYOGENIC This refers to the heart’s ability to generate its own Stage 1: Sino-atrial node (SA node) Located in the right atrial wall, the SA node generates the SA NODE electrical impulse and fires it through the atrial wall causing both the left and right atria to contract. Stage 2: Atrio-ventricular node (AV node) SA NODE AV NODE The AV node collects the impulse from the SA node but delays the transmission of the impulse by 0.1 seconds until the atria have finished contracting. Stage 3: Bundle of His The bundle of his is located in the septum of the heart. SA NODE AV NODE BUNDLE OF HIS The electrical impulse travels down the central structure of the heart. The electrical impulse splits in two. Stage 4: Bundle of branches left and right branches carry the The impulse up the left right ventricles SA NODE AV NODE BUNDLE OF HIS RIGHT BRANCH LEFT BRANCH and Stage 5: Purkyne fibres fibres distribute through the ventricle walls causing the Purkyne impulse ventricles to contract. SA NODE AV NODE BUNDLE OF HIS RIGHT BRANCH PURKYNE FIBRES LEFT BRANCH The conduction system overview Stage 1 Stage 2 Stage 5 Stage 4 Stage 3 Stage 5 Stage 4 The conduction system overview Conduction System: Task Task 1: Draw a flow chart illustrating the journey of the electrical impulse that controls the contractions of the heart. Be concise and use specific terminology. Task 2: Exam question (2004) Describe how the conduction system makes the heart chambers contract.