Topic List for Chapter 6 Neuronal Signaling and Structure of the Nervous System Know the examples of how certain drugs and diseases toxins act on synapses Diseases o Clostridium tetani prevents vesicle fusion with the membrane inhibiting neurotransmitter release and causes increased muscle contraction o Clostridium botulinum interferes with actions of SNARE proteins at excitatory synapses that activate muscles botulism characterized by muscle paralysis o Botox injected therapeutically to treat a number of conditions including facial wrinkles severe sweating uncontrollable blinking and misalignment of the eyes Drugs o Act by interfering with or stimulating normal processes in the neuron involved with neurotransmitter synthesis storage and release Know the difference between a neurotransmitter and a neuromodulator Neurotransmitter involved in rapid communication o Receptors affect ion channels that directly affect excitation or inhibition of the postsynaptic cell o Operate within milliseconds Neuromodulator associated with slower events such as learning development motivational states and some sensory and motor activities o Receptors bring about changes in metabolic processes in neurons o Can occur over minutes hours or days Know what a neuroeffector junction is and how it works Neurons synapse on muscle and gland cells o Neurotransmitter is released from the efferent neuron diffuses to the surface of the effector cell where it binds to receptors on that cell s plasma membrane o Receptors on the effector cell may be either ionotropic or metabotropic metabolic Know the major classes of neurotransmitters neuromodulators important facts about each Table 6 6 Actetylcholine important neurotransmitter in the PNS especially at neuromuscular junctions o Neurons that release ACh are called cholinergic neurons ACh is broken down by the enzyme acetylcholine esterase in the synaptic cleft Altzheimer disease is associated with the degeneration of cholinergic neurons o Receptors for ACh are called nicotinic and muscarinic Biogenic Amines synthesized from amino acids o Examles are dopamine epinephrine norepinephrine serotonin and histamine o Norepinephrine NE and epinephrine Epi or adrenaline are secreted from the adrenal gland NE and Epi stimulate fight or flight response Cells that produce these are called adrenergic In group called catecholamines which also includes dopamine o Seratonin affects food intake reproductive behavior mood and anxiety Main location is CNS in the brainstem Antidepressants called SSRI selective serotonin reuptake inhibitors act to prevent the reuptake of serotonin from the synapse and keep its concentration there high o Histamine CNS neurotransmitter located in hypothalamus known for paracrine actions Involved in allergic reactions nerve sensitization and acid production in stomach Make you stay awake Antihistamine make you sleepy Amino acid neurotransmitters some neurotransmitters are made of amino acids o Glutamate and Aspartate excitatory Glutamate is an excitatory neurotransmitter used by 50 of the excitatory synapses in the brain o Glycine and GABA inhibitory Alcohol activates GABA inhibitor xanax and ethanol act on these receptors Neuropeptides made of short chains of amino acids o Neurons that produce these are called peptidergic o endogenous opioids beta endorphins and dynorphins that are probably involved in regulating pain and in runner s second wind The receptors for these are acted upon by morphine heroin etc and are analgesics Gases nitric oxide carbon monoxide and hydrogen sulfide act as neurotransmitters o Not released by exocytosis and don t have receptors o Diffuse from the axon terminal into the cytoplasm of the postsynaptic cell o Nitric Oxide learning development and drug tolerance Know the major divisions of the nervous system Figure 6 37 Central Nervous system o Brain and spinal cord Peripheral Nervous system o Afferent division going into the CNS Somatic sensory consciously experienced Visceral sensory don t consciously experience it Special sensory eyes ears taste o Efferent division leaving the CNS Somatic motor conscious movement Autonomic motor non conscious movement blood pressure heart rate Sympathetic fight or flight respiratory functions Parasympathetic calming rest and digest sexual behavior Enteric autonomic neurons innervate a nerve network in the wall of the intestinal tract Know the major anatomical structures of the brain and their general functions see Table 6 7 Forebrain o Cerebral hemispheres Cerebral cortex perception skilled movements reasoning learning and memory Outer shell of gray matter and inner layer of white matter Ridges gyri grooves sulci Contain subcortical nuclei participate in coordination of skeletal muscle activity Contain interconnecting fiber pathways gray matter internal Corpus callosum massive branch of nerve fibers Synaptic relay station for sensory pathways on their way to the cerebral cortex Participates in control of skeletal muscle Plays a key role in awareness o Thalamus o Hypothalamus Single most important control area for homeostatic regulation of internal environment body temp water balance eating and drinking behavior etc Connected to pituitary gland o Limbic system thalamus hypothalamus portions of frontal and temporal lobes Generation of emotions and emotional behavior Plays essential role in most kinds of learning Cerebellum Brainstem o Coordinates movements including those for posture and balance o Participates in some forms of learning o Contains all fibers passing between spinal cord forebrain and cerebellum o Contains reticular formation absolutely essential for life and integrating centers o Contains nuclei for cranial nerves 3 12 Know the anatomy of the spinal cord including the dorsal and ventral roots and ganglia What are the functions of each Fig 6 41 Spinal cord slender cylinder of soft tissue about as big as the little finger Dorsal horns gray matter projecting towards the back of the body Gray matter surrounded by white matter which consists of myelinated axons opposite of brain Dorsal root where afferent fibers enter from peripheral nerves Ventral horns gray matter projecting towards the front of the body o Dorsal root ganglia small bumps on dorsal root that contain cell bodies of afferent neurons Ventral root axons of efferent neurons leave spinal cord here Know the different divisions of the afferent and efferent division of the PNS and what they are responsible for Know the set