8. Lectures 18, 19 Flashcards
What are the 3 important differences between the sympathetic and parasympathetic divisions of the ANS?
(Also study both of them on slide 3 lecture 18)
- Location of preganglionic neuron in CNS
- Location/organization if autonomic ganglia
- Neurotransmitter/receptor system at the synapse
Slides 3-5 lecture 18
What are the 4 cranial nerves parasympathetic fibers originating in brain distribute to?
- Oculomotor Nerve (CN III)
- The Facial Nerve (CN VII)
- The Glossopharyngeal Nerve (CN IX)
- The Vagus Nerve (CN X)
Vague nerve has a lot of innervation (splits and goes to multiple sections in body)
Slide 6 lecture 18
What are the 3 dates of the preganglionic sympathetic axon?
- It synapses within that segmental paracertebral ganglion (sympathetic chain)
- It travels up or down the sympathetic chain to synapse within a neighbouring paravertebral ganglion
- It enters the splanchnic nerve to synapse within one of the ganglia of the prevertebral plexus
Slide 7 lecture 18
What is the breakdown of the pathways of parasympathetic and sympathetic systems?
(Preganglion, postganglion, neurotransmitters)
Slide 8 lecture 18
Parasympathetic
Longer preganglionic fiber, releases ACh at N2 receptor at ganglion
Short post ganglionic fiber that releases acetylcholine at muscarinic acetylcholine receptor
Sympathetic
Short preganglionic fiber, releases ACh at N2 receptor at ganglion
Long post ganglionic fiber that releases norepinephrine at α and β adrenergic receptors
Which preganglionic and post ganglionic fibers have myelination?
Parasympathetic
Preganglionic- myelination
Postganglionic- myelination
Sympathetic
Preganglionic- myelination
Postganglionic- no myelination
What are the effects of parasympathetic and sympathetic pathways on main organs such as; Heart Lungs Eye Adrenal medulla
Parasympathetic
Heart- decreases rate, decrease force of contraction
Lungs- construction of bronchioles (airways), mucus secretion
Eye- construction of pupil, adjust vision for near sight
Adrenal medulla- none
Sympathetic
Heart- increases rate and force of contraction
Lungs- dilation of bronchioles, inhibition of mucus secretion
Eye- dilation of pupil, adjust vision for far sight
Adrenal medulla- stimulation of epinephrine and norepinephrine secretion
What is the adrenal medulla pathway?
Chromaffin cells have nicotinic ACh receptors
These chromaffin cells reside near blood vessels and release epinephrine into bloodstream
Epinephrine enhances the ability of the sympathetic division to broadcast its output through the body
Adrenal medulla is activated as part of sympathetic response
Slides 11-13 lecture 18
What are autonomic varicosities?
Axons of postganglionic neurons make multiple points if contact (varicosities) with their targets
Like octopus suction cups on tentacle but on smooth muscle in GI tract
What are the 3 contributors to contraction of smooth muscle?
ATP (nonclassic transmitter) and norepinephrine are co released Neuropeptide Y (NPY) contributes to contraction
All increase Ca2+, all cause contraction
ATP produces rapid contraction
NE produces moderately fast response
NYP produces slowest response
Slide 15 lecture 18
What 3 things contribute to dilation of smooth muscle?
Co-release of ACh, nitric oxide (NO), and VIP (vasoactive intestinal polypeptide) all decrease Ca2+ and cause dilation of smooth muscle
Slide 16 lecture 18
How is M-current inhibited by muscarinic Rs?
Happens in fight or flight (sympathetic)
Burst of ACh release during fight or flight activated ionotropic and metabotropic receptor
Membrane potential depolarizes
Slide 17 lecture 18
What is sensory transduction?
Sensory receptors concert environmental energy into neural signals
Sensation begins with sensory receptors that interface with the world, these receptors use energy from the environment to trigger electrochemical signals that can be transmitted to the brain
Slide 9 lecture 18
What are sensory modalities?
Seeing Hearing Touching Smelling Tasting
Pain
Balance
Body position
Movement
What is afferent versus efferent information?
Afferent goes from sensory receptor to the brain to be integrated
Efferent moves from brain after integration to effective
Slide 4 lecture 19
What are the 3 major functions of the somatosensory system?
- Proprioception- sense of oneself
Receptors in skeletal muscle, joint capsules, and skin generate conscious awareness of posture and movements - Exteroception- sense of direct interaction with the external world as it impacts the body (touch, pain)
- Interoception- sense of the function of the major organ systems in the body and its internal state
Interoceptors are primarily chemoreceptors (blood gases and pH)