Lecture 3: Autonomic Nervous System Flashcards
Where can we find cues for the afferent (sensory) neurons?
Visual Cues Auditory Cues Baroreceptors (blood pressure) Chemoreceptors (oxygen levels) Stretch of smooth muscles
Where in the brain are autonomic responses processed?
Hypothalamus
What composes the autonomic reflex arc?
Afferent (sensory) neuron
α-motor neuron
In the ANS, how many neurons are between the CNS and end organ (target)?
2 Neurons: Pre-synpatic and Post-synaptic
aka Pre-ganglionic and Post-ganglionic
Where is the cell body of pre-synaptic neuron?
Where does it terminate?
Cell body in CNS
Terminates in a ganglion in periphery
Where is the cell body of post-synaptic neuron?
Where does it terminate?
Cell body in ganglion
Terminates at the end organ (target)
Where are the two synapses happening?
Synapse 1: Ganglion
Synapse 2: End organ (target)
Which synapse is the same between sympathetic and parasympathetic systems?
Synapse 1 at the ganglion
What neurotransmitter is released between the pre-synaptic and post-synaptic neurons?
What receptor does the post-synaptic cell have for this NT?
Acetylcholine
Nicotinic Cholinergic Receptors
What is the difference between an en passant synapse and regular neural synapses?
En passant synapse are located anywhere on the axon while regular neural synapses happen at axon terminal
-Both do the same exact thing, just have different structure
How is NT release different between NMJ and varicosities?
NMJ: NT released into synaptic cleft and goes directly to receptors on post-synaptic cells
Varicosities: NT released and are diffused until it finds receptors on post-synaptic cells
In the parasympathetic system, what NT is released from the post-synaptic cell and received by the end target organ?
What receptors does the end target organ have?
Acetylcholine
Muscarinic Cholinergic Receptors
What type of receptors are M1R, M3R, and M5R?
Gq Muscarinic acetylcholine receptors
-Increase Calcium in cell
What type of receptors are M2R and M4R?
Gi Muscarinic acetylcholine receptors
-Opens Potassium channels and can hyperpolarize cell
What structures have M1 receptors?
What happens when they are activated?
Salivary Glands: Increased secretion
Acid Secreting cells of Stomach: Increased secretion
What structures have M3 receptors?
What happens when they are activated?
Smooth Muscle Cells: Contraction
Exocrine glands: Secretion
What structures have M2 receptors?
What happens when they are activated?
Cardiac cells: Slow heart rate
In the sympathetic system, what NT is released from the post-synaptic cell and received by the end target organ?
What receptors does the end target organ have?
Norepinephrine (Adrenaline)
Adrenergic Receptors
What are two main classes of adrenergic receptors?
α-adrenergic
β-adrenergic
What type of receptors are α-1 adrenergic receptors?
Gq
Increased calcium in cell
What type of receptors are α-2 adrenergic receptors?
Gi
Decreased cAMP
What type of receptors are β-adrenergic receptors?
Gs
Increased cAMP
What structures have α-1 adrenergic receptors?
What happens when they are activated?
Smooth muscle of blood vessels: contraction
Smooth muscle of urinary and reproductive tract
Liver: glycogenolysis and gluconeogenesis
Adipose Tissue: Lipolysis
Lacrimal Glands: reduced watery secretion
Radial muscle of iris contraction: Dilation of pupil
What structures have α-2 adrenergic receptors?
What happens when they are activated?
GI sphincters: contraction
Pancreas: release glucagon and decrease insulin
Smooth muscle of blood vessels: dilation
Platelets increased
What structures have β-1 adrenergic receptors?
What happens when they are activated?
SA Node: Increased HR
Ventricular Muscles: Increased strength of contraction
Salivary Glad: Secretion
Adipose Tissue: Lipolysis
What structures have β-2 adrenergic receptors?
What happens when they are activated?
Bronchiole smooth muscle: relaxation
GI smooth muscle: relaxation
Relaxation of ciliary muscle: flattens lens (can see distance better)
What structures have β-3 adrenergic receptors?
What happens when they are activated?
White adipose tissue: lipolysis
Brown adipose tissue: heat production
What NT is released when the pre-synaptic ganglion synapses at the adrenal gland?
Where does the NT bind to?
Acetylcholine
Nicotinic Receptors on chromaffin cells
