Ans reflexes maintain homeostasis: ans works w/ endocrine system and behavioural state system to maintain homeostasis, homeostasis is a dynamic balance between the autonomic branches. Anatomy & function: parasympathetic innervation primarily to head, neck, and internal organs. Ach which binds muscarinic receptor or target tissue metabotropic response: adrenergic receptor and muscarinic receptor = Ach molecules, opening a nonspecific monovalent cation channel: open channel allows na+ and k+ to pass. 2: net na+ influx depolarizes the muscle, depolarization opens voltage-gated ca2+ fiber channels, ach binding causes an epsp on post- ganglionic neuron more na+ flows in than k+ flows out. Sympathetic pathways: secrete catecholamines that bind to adrenergic receptors on their target cells, adrenergic receptors are gpcrs target cell response is slower to start and lasts longer, adrenergic receptors come in two varieties: Receptors respond strongly to norepinephrine and weakly to epinephrine (ne > e: 1-receptors activate phospholipase c create. Norepinephrine cycle at a sympathetic varicosity: action potential arrives at varicosity.