NEUR 0010 - Chapter 15 Flashcards
What are three components of the NS that operate in expanded space and time?
The secretory hypothalamus, the ANS, and the CNS
What controls the ANS?
The hypothalamus
What kind of postsynaptic receptors does the CNS use?
Metabotropic
What are diffuse modulatory systems of the brain?
Part of the CNS: regulate level of arousal and mood, among other things
How do the functions of the hypothalamus and thalamus differ?
Hypothalamus = integrating somatic/visceral responses in accordance with the brain’s needs; Thalamus = pathway to the neocortex
What are the three zones of the hypothalamus?
Periventricular, medial, and lateral
What are the three main cell types in the PVZ of the hypothalamus?
Suprachiasmatic nucleus (receive direct retinal innervation, synchronize circadian rhythms); control ANS; neurosecretory neurons
What hypothalamic cells extend into the posterior pituitary?
Magnocellular neurosecretory cells
What two neurohormones do the magno neurosecretory cells release into the posterior pituitary?
Oxytocin and ADH
How do the kidneys and liver regulate blood volume and pressure?
Kidneys release renin, which converts angiotensinogen (from liver) into angiotensin I, into angiotensin II, which acts directly on blood vessels and the kidney
What part of the brain detects angiotensin II?
Subfornical organ
What hypothalamic cells extend into the anterior pituitary?
Parvocellular neurosecretory cells
How does the hypothalamus secrete to the anterior pituitary?
Extend axons to special capillary bed in the upper pituitary to release hypophysiotropic hormones; these HPThormones, hit the hypothalamo-pituitary portal circulation and travel until they bind in the anterior pituitary, which releases or stops hormones in the general circulation
How do the cell bodies of the somatic and autonomic lower motor neurons differ?
Somatic = in the CNS (ventral horn or brain stem); Autonomic = outside CNS, in the autonomic ganglia
What does it mean that the ANS uses disynaptic pathways?
Preganglionic neuron from the spinal cord/brain stem to the autonomic ganglia, then a post ganglionic neuron from the autonomic ganglia to the target cells
What is the difference in emergence between the sympathetic and parasympathetic ANS?
Sympathetic: emerge in upper third (thoracic/lumbar); Parasympathetic: emerge in cervical and sacral (upper and lower extremes)
Where are the preganglionic neurons the sympathetic ANS?
Intermediolateral gray matter of the spinal cord: sand axons through ventral roots to synapse on sympathetic chain ganglia, next to spinal column, or in collateral ganglia in the abdominal cavity
Where are the two places that preganglionic sympathetic ANS neurons can synapse?
Sympathetic chain ganglia next to the spinal column, or collateral ganglia in the abdominal cavity
Where are the preganglionic neurons of the parasympathetic ANS?
Brain stem nuclei and lower spinal cord: send axons within cranial nerves and sacral nerves to right next to the target organs
What are the three types of tissue innervated by the ANS?
Glands, smooth muscle, and cardiac muscle
What are the two divisions of the enteric system?
Myenteric plexus and submucous plexus
What does the nucleus of the solitary tract do?
Autonomic control: integrates sensory info from internal organs and coordinates output to autonomic brain stem nuclei
Why do most drugs have greater effect on ANS vs CNS?
ANS ganglia outside the BBB
What is the primary transmitter of the peripheral ANS?
ACh: released by the preganglionic neurons of the SANS and the PANS
What kinds of ACh receptors does ACh bind to, after being released by the SANS and PANS pregang neurons?
Nicotinic: nAChR, evokes fast EPSP; AND muscarinic: mAChR, evokes slow EPSP/IPSP
What is the difference in NT secretion by the postgang SANS and PANS?
PANS also secretes ACh (like pregang), but SANS mostly secretes NE
What are the effects of postgang PANS ACh?
Fast mAChR local response
What are the effects of postgang SANS NE?
Far spreading effect
What does it mean for a drug to sympathomimetic?
Mimic activation of SANS: promote NE and inhibit ACh
What does it mean for a drug to be parasymathomimetic?
Mimic activation of PANS: inhibit NE and promote ACh
Which of these are sympathomimetic vs parasympathomimetic?
Atropine is SANS, propanolol is PANS
What are the four main characteristics of diffuse modulatory systems?
The core is usually a small set of neurons; the core neurons arise from the brain’s core, usually the brain stem; they contact tens of thousands of neurons; the synapses are made through ECF, so it’s very diffuse
What is the locus coeruleus?
Tiny spot in pons that uses NE
What do we believe is the importance of the locus coeruleus to attenion?
Increases brain responsiveness, especially to novel stimuli
What are the raphe nuclei?
Spots on the sides of the midbrain; secrete 5HT
What is the difference in caudal vs rostral raphe nuclei?
Caudal innervates the spinal cord for pain-related signals; Rostral innervates similarly to the locus coeruleus
The locus coeruleus and the Raphe nuclei are both part of what system?
Ascending reticular activating system: core of arousal and awakening of the forebrain
What are the brain structures most concentrated in DA?
Substantia nigra, ventral tegmental area
What is the mesocortiolimbic dopamine system?
The dopaminergic projection from the midbrain, related to reward and reinforcement
What are the two major diffuse modulatory systems for ACh?
Basal forebrain complex and pontomesencephalotegmental complex
What is the basal forebrain complex?
Scattered cholinergic neurons around the telencephalon: medial septal nuclei and basal nucleus of Meynert
What are the two parts of the basal forebrain complex?
Medial septal nuclei and basal nucleus of Meynert
What is the importance of the basal forebrain complex?
First to die in Alzheimer’s; important for learning and memory
What is the importance of the pontomesencephalotegmental complex?
In pons and midbrain tegmentum: acts on dorsal thalamus; regulates excitability of sensory relay nuclei; cholinergic link between brain stem and basal forebrain complexes
What NT does LSD affect?
Serotonin: potent agonist on the presynaptic terminals of raphe nuclei neurons
What NTs do cocaine/amphetamines affect?
DA and NE: sympathomimetic
What is the difference in mechanism between cocaine and amphetamines?
Cocaine = selective DA reuptake; Amphetamines: blocks NE and DA reuptake AND release of DA
