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43 Cards in this Set
- Front
- Back
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What are the names of the supporting cells in the CNS and PNS and what are their functions?
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- glial cells in the CNS - Schwann cells in the PNS - supporting cells protect the nervous system and provide metabolic support for the neurons
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What are the 3 parts of the neuron?
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1. cell body (or soma) 2. dendrites - conduct information to the cell body 3. axons - carry impulses away from the cell body
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What is the blood-brain barrier?
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- a term used to emphasize the impermeability of the nervous system to large or potentially harmful molecules - composed of astrocytes and tightly joined endothelial cells of the capillaries in the CNS
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What are characteristics of myelin?
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- increases the velocity of nerve impulse conduction in axons - has a high lipid contents, which gives it a whitish color (white matter is myelinated fibers of the spinal cord and brian) - produced by Schwann cells in the PNS and oligodendroglia cells in the CNS
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Name 2 disorders of myelin degeneration
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1. multiple sclerosis in the CNS 2. Guilliain-Barré syndrome in the PNS
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What are the 2 types of supporting cells in the PNS?
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Schwann cells and satellite cells
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What are nodes of Ranvier?
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- short extracellular fluid gaps where the myelin is missing and where volage-gated sodium channels are concentrated. - increases nerve conduction by allowing the impulse to jump from node to node through the extracellular fluid (called saltatory conduction)
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What are the names and functions of the 4 supporting cells in the CNS?
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1. Oligoentroglial cells - form the myelin in the CNS 2. Astrocytes - provide a tranposrt mechanism for the exchange of oxygen, carbon dioxide, and metabolites 3. Microglial - phagocytic cell for cleaning up debris after cellular damage, infection, or cell death 4. Ependymal cell - forms the lining of the neural tube cavity and the ventricular system. also forms the choroid plexus where CSF production takes place
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What are the 3 phases of the action potential?
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1. resting or polarized state 2. depolarization 3. repolarization
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What is threshold potential?
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represents the membrane potential at which nurons or other exitable tissues are stimulated to fire
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What causes repolarization?
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the closure of sodium channels and opening of potassium channels
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What is the difference between hypopolarization and hyperpolarization of the postsynaptic membrane?
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- hypopolarization increase the excitability of the postsynaptic neuron by bringing the membrane potential closer to the threshold potential - hyperpolarization brings the membrane potential further from the threshold and has an inhibitory effect
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What are 3 major types of neurotransmitters?
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1. amino acids (ie glutamic acid and GABA) 2. Peptides (ie endorphins and enkephalins) 3. monamines (epinephrine and norepinephrine)
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What are the 4 major plexuses in the PNS?
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- cervical plexus - brachial plexus - lumbar plexus - sacral plexus
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What are the 3 regions of the brain and name structures associated with each region?
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1. Hindbrain - includes medulla oblongata, the pons, and the cerebellum 2. Midbrain - includes the superior and inferior colliculi 3. Forebrain - consists of 2 hemispheres covered by the cerebral cortex, central masses of gray matter, the basal ganglia, and the diencephalon
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What is the tentorium cerebelli?
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a fold of dura mater that separates the cerebellum from the cerebral hemispheres
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What are functions of the cerebellum?
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- receives proprioceptor input from the vestibular system - receives feedback from muscles, tendons, and joints - receives indirect signals from the somesthetic, visual, and auditory systems that provide background information for ongoing movment - dampening of muscle movement
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Which cranial nerves originate from the medulla?
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CN 7-12
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Which cranial nerves exit the midbrain?
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cranial nerves III & IV
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What are the cerebral peduncles?
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- two prominent bundles of nerve fibers that pass along the ventral surface of the midbrain - fibers include the corticospinal tracts - main motor pathway between the forebrain and the pons
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What are the functions of the superior and inferior colliculi?
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- superior colliculi are involved in controlling conjugate eye movements - inferior colliculi is involved in directional turning and experiencing the direction of sound waves
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What is the corpus callosum?
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- a massive bridge of myelinated axons that connects the cerbral cortex of the two sides of the brain
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What are strucutures make up the basal ganglia?
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- caudate nucleus - putamen - globus pallidus
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What structures make up the lentiform nucleus?
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globus pallidus and putamen
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What are the functions of the thalamus?
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- coordination and intergratio of peripheral sensory stimuli - relays criticial information regarding motor activities to and from selected areas of the motor cortex
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What are functions of the hypothalamus?
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- is the area of master-level integration of homeostatic control of the body's internal environment - controls maintenance of blood gas concentration, water balance, food consomption, and major aspects of endocrine and autonomic nervous system control
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What is the function of the basal ganglia?
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- supplies axial and proximal pstures and movements, which enhance and add gracefulness to UMN-controlled manipulative movements - ex. arm swing during walking and running; follow-through movement involved in throwing a ball
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What is the function of the temporal lobe?
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• important in discrimination of sounds entering opposite ears • important in long-term memory recall
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What structures make up the limbic system?
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- the limbic cortex (cingulate gyrus, parahippocampal gyrus, uncus) and associated subcortical structures (thalamus, hypothalamus, amygdala)
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What is the function of the limbic system?
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- involved in emotional experience and in the control of emotion-related behavior
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What is the reticular formation?
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• located in the pons and medulla • contains networks controlling basic breathing, eating, and locomotion functions
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What menigeal layer contains CSF?
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CSF is contained in the subarachnoid space
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Trace the flow of CSF from the lateral ventricles to the subarachnoid space
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Lateral ventricles » Interventricular foramen » 3rd ventricle » Cerebral aqueduct » 4th ventricle » to exit into subarachnoid space
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What are the names of the openings that allow the CSF to pass into the subarachnoid space?
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• Foramina of Luschka • Foramina of Magendie
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What are the 2 barriers that enable the brain to maintain a stable chemical environment?
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• Blood-Brain barrier • CSF-brain barrier
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What are the 3 components of the blood-brain barrier?
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• astrocyte • capillary basement membrane • tight junctions that join the overlapping capillary endothelial cells
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How does the brain remove toxic waste products from the CNS?
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A major function of the CSF is removal of toxic waste products
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How does CSF get reabsorbed into the vascular system?
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• reabsorption occurs along the sides of the superior sagittal sinus in the anterior and middle fossa through arachnoid villi
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What part of the brain serves as the major control center for most autonomic-mediated functions, such as thermoregulation, thirst, and appetite?
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hypothalamus
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Where is acetylcholine released?
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• at all preganglionic synapses in autonomic ganglia of sympathetic and parasympathetic fibers • postganglionic synapses of all parasympathetic nerve endings • at sympathetic nerve endings that innervate sweat glands and vasodilator fibers in skeletal muscles
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Where is norepinephrine release at?
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sympathetic nerve endings
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What neurotransmitter is a precursor to norepinephrine?
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dopamine
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The catecholamines are synthesized from what amino acid?
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tyrosine
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