Lecture 1 Flashcards
What was the basis of Loewi’s Experiment?
One heart was in fluid continuity with another. Stimulate the vagus nerve of one heart, slows down both hearts. Why? Chemical NT diffuses from site of stimulation to the other heart.
Sympathetic Ganglion -Ganglion Length, NT release, Exceptions?
Ganglion:
Presynaptic: Short, has to to go the sympathetic chain which is beside the SC. Releases Ach
Post Ganglionic: Long, travels to the site of action NA/A
Direct innervation of adrenals (Ach), only autonomic system that innervates BV
Parasympathetic Ganglion - Ganglion length, NT release, Exceptions?
Presynaptic: Long, Ach release
Postsynaptic: Short, Ach release
How is Ach Synthesized?
Choline is taken into the cell via choline carrier -> Mitochondria produces and releases Acetyl CoA into the cytoplasm-> Choline Acetyl Transferase ‘combines’ Acetyl CoA and Choline -> Acetyl Choline -> Ach Carrier Protein -> placed into vesicle.
How is NA/A Synthesized?
Tyrosine -> into cell via protein -> tyrosine converted into L-DOPA via Tyrosine Hydroxylase -> L-Dopa converted to Dopamine via Dopa decarboxylase -> Put into vesicle where Dopa Hydroxylase converts Dopamine into NA -> NA converted to Adrenaline via PN methyl transferase.
How is Ach degraded?
AchE degrades Ach in the extracellular space to Acetyl and Choline.
How is NA degraded/re-uptaken?
Via High Affinity Uptake 1 channel in the PRESYNAPTIC
Via Low Affinity Uptake 2 channel in the POSTSYNAPTIC
What kind of receptors are found on the post synaptic membrane?
Nicotinic R - Ach
What kind of receptors are found on the target membrane?
GPCR - Adrenergic Receptors
Muscarinic Metabotropic Receptors - Ach
What part of the autonomic system innervates the sweat glands?
Sympathetic…post ganglionic fiber releases Ach onto the MusR located on the sweat glands.
