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40 Cards in this Set
- Front
- Back
What are the three general components of an ANS reflex arc?
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Comprised of sensory, integrative elements, and motor.
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Give an example of an ANS arc. Include the circuit.
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Neuron from sensor for body temperature => dorsal ganglion => synapse in ventral horn => gangion => viseral muscle of blood vessel.
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What is the overall function of the parasympathetic NS?
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It delivers signals to various visceral organs and glands. By analogy, it can be deseribed as "rest/digest".
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With what nerves/spinal cord segments are the parasympathetic fibers associated?
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III - pupillary constrictor, cillary body
VII - Lacrimal gland, some salivary glands. IX - Salivary glands X - thoracic and abdominal viscera S1-3 - pelvic viscera (Pelvic N.) |
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What is the overall function of the sympathetic NS?
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Deals with "Fight or Flight". In more normal situations, it opposes the parasympathetic system and will tend to shut down things that are turned on by the PSNS.
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With what spinal cord segments are the fibers of the sympathetic NS associated?
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thoracic and lumbar spinal cord segments, T1-L2/L3
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What are the two functions of the ANS?
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Internal homeostasis
Response to stressors. |
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Where are the peripheral efferents for the PSNS?
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Craniosacral regions
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What is the fanout of parasympathetic effects versus sympathetic efferents?
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PSNS: tend to act locally. Pre-ganglionic to post-ganglionic ratio is 1:3
SNS: tend to act more diffusely. Pre-ganglionic to post-ganglionic ratio is 1:10. |
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From what part of the cord do SNS pre-ganglionic fibers arise?
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Lateral horn.
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What is a terminal ganglion?
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The target area for a post-ganglionic parasympathetic fiber. It is often a diffuse set of neurons located within the target.
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What is a paravertebral ganglion?
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A line of SNS ganglia which follow the spinal colum. Pre-ganglion and post-ganglion fibers synapse here.
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What is a prevertebral (collateral) ganglion?
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For deeper organs, like the heart and digestive system, SNS pre-ganglionic fibers skip the paravertebral ganglia and synapse a ganglia closer to the target.
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Trace the circuit for the autonomic innervation fo the pupil (start at the nasal part of the retina)
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Optic nerve -> descussate optic chiasm -> optic tract -> synapse in pretectal nuclei to bi-lateral parasympathetic fibers of III -> snapse to neurons in the Edinger-Westphal nucleus -> synapse in ciliary ganglion (right and left) -> muscles of iris on each side.
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Identify the neurotransmitters released on the peripheral autonomic nerve fiber termni.
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ACh.
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Define the signs of Horner's syndrome.
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miosis (small pupil), ptosis (drooping eyelid), anhidrosis (lack of perspiration on the skin).
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What is the basic cause for Horner's syndrome?
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Loss of sympathetic innervation to the head.
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What is the basic circuit in which a leison can occur which leads to Horner's syndrome?
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hypothalamus -> brainstem/spinal cord -> sympathetic pathways between the eye/face through T1/T2 spinal cord segments.
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What causes miosis, ptosis, and anhidrosis in Horner's syndrome?
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miosis - unopposed parasympathetic innervation
ptosis - loss of sympathetic input to the smooth muscle of the upper eye lid. Anhidrosis - Lack of sympathetic input to the sweat glands of the face. |
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List the three functions of the hypothalamus.
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Coordinator of the endocrine system
Coordinator of the ANS Coordinator of the limbic system |
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In the hypothalamus, the medial and lateral zones are defined by the location of what structure?
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columns of the fornix
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What are the three regions in the medial zone of the hypothalamus?
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posterior (mamillary) region
tuberal region anterior (supra optic) region |
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What are the two nuclei in the posterior region of the hypothalamus?
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posterior nucleus and mamillary nucleus
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What structure passes through the lateral zone of the hypothalamus.
What is its orgin and destination? What is its function? |
Medial forebrain bundle.
From basilar parts of forebrain to brainstem. "highway" for autonomic control |
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What are the three nuclei in the tuberal region of the hypothalamus?
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dorsalmedial and ventralmedial nuclei. arcuate nucleus
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What are the four nuclei in the anterior (supra optic) region of the hypothalamus?
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Parventricular nucleus
Supraoptic nucleus Anterior nucleus Suprachiasmatic nucleus |
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What is the function of the parventricular and supraoptic nuclei?
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Neuroendocrine functions
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What is the function of the Suprachiasmatic nucleus?
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circadian rhythms
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What is the function of the Dorsomedial and Ventromedial nuclei?
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Satiety (possibly appetite)
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What is the function of the acruate nucleus?
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Relase of factors influencing the anterior pituitary.
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What is the function of the posterior nucleus?
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sympathetic activity
sleep-wake cycles |
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What is the function of the mamillary nuclei?
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Memory
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What are the two neurosecretory systems that influence the pituitary?
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Magnocellular
Parvocellular |
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Where are parvocellular nuclei found? What is their size? Where do their axons descend? What happens to the neurotransmitters they release?
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Arcuate
Small nuclei Anterior pituitary (adenohyphysis) NT (releasing/inhibiting factors) released into portal system. Pituitary will release various hormones into the blood depending upon the factors stimulating it. |
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Where are the Magnocellular nuclei found? What is their size? Where do their axons descend? What happens to the neurotransmitters they release?
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Paraventricular and Supra Optic regions.
Axons descend into the posterior pituitary (Neurohypophysis) They release ADH and ocytocin directly into the blood stream. |
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What is the name of the tract that carries information from the hypothalamus to/from the brainstem and spinal cord? What do the descending fibers do?
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dorsal longitudinal fasciculus
Descending fibers: control of GVE neurons. |
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What is the largest input tract to the hypothalamus? What two bodies are connected by this? What system is connected by this?
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fornix
hippocampus to mammillary bodies link between limbic system and hypothalamus. |
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What is the principle center and integrator of ANS activity?
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hypothalamus
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What are the three primary areas or systems that feed the hypothalamus?
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RF
limbic system GVA (spinal cord and brain stem) |
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What part of the hypothalamus drives the sympathetic NS? The parasympathetic NS?
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posterior - sympathetic
anterior - parasympathetic |