BSCI 202 Lecture Notes - Lecture 9: Thyroid Hormones, Adrenal Gland, Cardiac Muscle

• School: University of Maryland
• Department: Biological Sciences Program
• Course: BSCI 202
• Professor: Obrien

Document Summary

Sa node intrinsic firing rate=100 bpm (without pacemaker) Sa node under control of autonomic nervous system and hormones. Increased sympathetic activity beta 1 receptors in sa node increase open state of if and ca channels increase rate of spontaneous depolarization (increase action potentials increased hr. Increased parasympathetic activity (vagus nerve) muscarinic cholinergic receptors in. Sa node increase open state of k+ channels and closed state of ca channels decreased rate of spontaneous depolarization and hyperpolarization of cells (decreased action potentials) decreased hr. Epinephrine/norepinephrine: have same effect of sympathetic nervous system input (adrenal gland) Sympathetic nervous system: crisis, low bp. High bp or low bp as result of negative feedback. Electrical flow sa node av node av bundle (bundle of his) bundle branches purkinje fibers.