6.1.3 Controlling heart rate Flashcards
Response
Structure of nervous system
Central nervous system and peripheral nervous system
Peripheral nervous system
Somatic and autonomic nervous system. Somatic nervous system controls conscious activities. Autonomic nervous system controls unconscious activities
Autonomic nervous system
Sympathetic gets body ready for action. Parasympathetic calms body down
Myogenic
Cardiac muscle is myogenic, can contract and relax without receiving signals from nerves
SAN (sinoatrial node)
In the right atrium, acts as a pacemaker by sending regular waves of electrical activity to atrial walls. Controlled by medulla
AVN (atrioventricular node)
Electrical activity transferred from SAN to AVN. Responsible for passing impulses to bundle of His. Delay to ensure atria emptied before ventricle contracts
Bundle of His
Muscle fibres responsible for conducting electrical activity between ventricles to apex. Splits into Purkyne tissue
Purkyne tissue
Finer muscle fibres in right and left ventricle walls, carries waves of electrical activity into muscular walls of ventricles so they contract simultaneously
Baroreceptors
Pressure receptors in the aorta and carotid arteries
Chemoreceptors
Chemical receptors in the aorta, carotid arteries and medulla. Monitor oxygen levels, CO2 levels and pH
High blood pressure
Baroreceptors detect high blood pressure, send impulses along parasympathetic neurones. Secretes acetylcholine, binds to receptors on SAN. Heart rate slows down
Low blood pressure
Baroreceptors detect low blood pressure, sends impulses along sympathetic neurones. Secretes noradrenaline, binds to receptors on SAN. Heart rate speeds up
High blood O2/pH levels
Chemoreceptors detect chemical changes, sends impulses along parasympathetic neurones. Secrete acetylcholine, binds to receptors on SAN. Heart rate decreases
Low blood O2/pH levels
Chemoreceptors detect chemical changes, sends impulses along sympathetic neurones. Secrete noradrenaline, binds to receptors on SAN. Heart rate increases
