Describe the components of the Sympathetic Nervous System
Preganglionic cells come from T1-L2 and are SHORT and end in the Paravertebral Chain Ganglia and the 3 Pre-Vertebral Chain Ganglia After they synapse in the ganglia, the post synaptic neurons are longer
Describe the components of the Parasympathetic Nervous System
Preganglionic neurons exit either on Cranial Nerves 3, 7, 9, 10 or at the Sacral Level S2-3 Preganglionic neurons are LONG and synapse in ganglia that are IN or close to target structures
What is the primary NT for the Pre-ganglionic neurons in the autonomic nervous system?
What is the primary NT for post-ganglionic neurons in the Parasympathetic system?
What is the primary NT for post-ganglionic neurons in the Sympathetic system?
NE except for some nerves that secrete Ach onto sweat glands or Da onto renal vascular beds
What drugs act on Choine Reuptake?
Hemacholiniums Inhibit Na+ Coupled Co-Transporters in Ach transmission
What do Amphetamines do to neruons?
Cause NON-vesicular release of NE from nerve terminals by reversing the NE transporter
What is the action of Cocaine on peripheral neurons?
stops NE transporter and allows it to be left in the synaptic cleft for longer periods of time enhancing transmitter action
Where and How is Epinephrine made?
Adrenal Medulla NE converted by PNMT enzyme
Nicotinic Autonomic Receptors - Location, Mechanism and Response
Found in autonomic ganglia and adrenal medulla AND Pre-synaptic Autoreceptors
Binding of Ach opens that receptor channel and generates an Inward current generates EPSP that are summed to get a large enough AP in post-ganglionic neurons to release Calcium
Nicotinic Muscle Receptors - location, mechanism and response
Found at the Neuromuscular Junction Ach binding opens ion channel and Na current depolarizes end plate potential in muscle membrane enough for AP in muscle cell and contraction
Muscarinic M1 Receptors - Location, Mechanism, Response
M1 receptors are found in Autonomic Ganglia Gq-coupled receptors activated increase IP3 and DAG for late EPSP in ganglia....or later contraction and secretion
Muscarinic M2 Receptors - Location, Mechanism, Response
M2 receptors are found in the SA node, the AV node, Atrium and Ventricle in the HEART!!!!!!! G1-Coupled and Ach binding leads to slower spontaneous depolarizations, hyperpolarization, decreased contraction velocity and refractory period and force and contraction strength ....reduce HR, Force of contraction etc
Muscarinic M3 Receptors - Location, Mechanism, Response
M3 receptors are found in SM, Glands, and Endothelium Activation with Ach leads to Gq-coupled increases of IP3 and DAG much like M1 response.....Here leads to Contraction and Secretion
Alpha 1 Adrenergic Receptors - Location, G protein mediator, Function
A1 found in Smooth Muscle of Vasculature, Intestines and Liver (and Iris and GU system) and Glandular tissue Use Gq, Gi, Go Activation leads to CONTRACTION of vascular SM to increase TPR Activation in Intestines leads to relaxation and viscous secretion from glands and K+ Secretion from liver Activation in Liver Leads to Glycogenolysis + Gluconeogenesis
Alpha 2 Adrenergic Receptors - Location, G proteins, and Function
Found in Pancreatic Beta Cells, Platelets, Nerve Endings, and Vascular SM Gi, Go Decreases transmitter release in nerve endings = Autoreceptor SM Contraction in vasculature Decreased insulin secretion from Pancreatic Beta cells Aggregation of Platelets
Beta1 Adrenergic Receptors - Location, G proteins, and Function
Found in CARDIAC MUSCLES!!!! and the Juxtoglomerular appartus of kidney Gs Activation increases rate of spontaneous depolarization (HR), Force of contraction, AV, CV and Renin Release
Beta 2 Adrenergic Receptors - Location, G proteins and Function
Found in SM cells of the LUNGS!!!, Liver and Skeletal muscle .... and mast cells Gs Activation Relaxes SM in lungs and vasculature - DILATION in Skeletal muscles and Liver Activation in skeletal muscles causes Tremor, increased Glucose and K+ Uptake Increases Glycogenolysis from liver Decreases Mast Cell release of granules
Beta 3 Adrenergic Receptors - Location, G proteins, and Function
Found in Adipose Cells and urinary bladder Gs Activation leads to increased Lipolysis and thermogeneration Also causes relaxation of urinary bladder
D1 Dopamine/Adrenergic Receptor - Location, G protein and Function
Found in Smooth muscle cells in Kidney and Mesentary Vascular beds Gs Activation relaxes renal, coronary and mesenteric vascular Smooth Muscles to dilate them
What is the action of Clonidine?
Clonidine is a neuromodulator that activates alpha-2 Adrenergic receptors on the PRESYNAPTIC cells to inhibit further NE release from neurons onto muscle cells..... Neuromodulator on HETERORECEPTOR
Predominant Autonomic Tone in Arterioles and Veins? What happens with ganglionic blockade?
Sympathetic and Adrenergic Blockade leads to vasodilation and increased flow to periphery and hypotension as well as peripheral pooling of blood and decreased venous return and CO
Predominant Autonomic Tone in Heart, Iris, ciliary body, GI tract, Urinary Bladder and what happens with ganglionic blockade?
Parasympathetic and Cholinergic Blockade in heart leads to Tachycardia In Eyes - Mydriasis (dilation) and Cycloplegia (loss of accomodation) In GI leads to decreased tone, motility - constipation and less gastric and pancreatic secretions in GU leads to Urinary retention In salivary glands leads to Xerostomia
Predominant tone in sweat glands? Blockade effects?
Sympathetic but with Ach!!!! blockade leads to Anhydrosis of skin - dry skin
Explain the Baroreceptor Reflex in terms of dual innervation
Increased BP sensed by stretch receptors in the Carotid sinus (or Aortic Arch) leads to increased Baroreceptor firing --> leads to increased Parasympathetic firing and Decreased Sympathetic firing ---> leads to decrease HR and force of contraction and TPR and venous Return Opposite is true for low BP
What are the autonomic receptors in the eye? What are their effects? Which system (para or sympa) is responsible for which responses?
Sympathetic - Alpha-1 receptor activation contracts Dilator Pupillae (Radial Muscle ) = Dilation
Parasympathetic - M3 receptor activation contracts the Constrictor Pupillae (Sphinctor Muscle) = Myosis
Cervical Sympathetic Neurons release Ach onto the Superior Cervical Ganglion and from there Nerves go to release NE onto targets:
1) Radial Muscles - dilation,
2) Mueller's Muscles - open eyelids
3) Vascular SM in face to constrict it
4) Ciliary Body in the eye for accomodation
Also Ach onto targets in Sweat glands for sweating in face In Horner's Syndrome, there is a problem with the Pre-ganglionic neuronal signal and so you see clinical presentation of Ptosis, Miosis, and Anhydrosis