MSN - FNP 590 CHAPTER 11 NEUROLOGICAL DISORDERS

MSN - FNP 590 CHAPTER 11 NEUROLOGICAL DISORDERS. NEURAL FUNCTION Anatomy and physiology: Brain: CNS Spinal cord: CNS Nerves: PNS (cranial and spinal nerves) 1. CNS – Meninges encase the cns, dura mater is the outer and toughest layer, arachnoid is middle, and pia is innermost that rests directly on brain and spinal cord. CSF fills space between arachnoid and pia mater (produced by choroid plexus cells in brain’s ventricles). 600 ml in adults and 50ml in newborns produced daily. -CSF: electrolytes, glucose, proteins, and red and white blood cells. Flow through cavities, foramens, and aqueducts of the brain. 150mls of it circulates within the ventricles and excess CSF drains into the bloodstream. -Neural tissue: neuroglia and neurons *Neuroglia: more numerous, scaffold neural tissue and isolate and protect neuron cell membranes, regulate interstitial fluid, defend neurons against pathogens, assist with neural repair. Consist of: astrocytes, oligodendrocytes, Schwann cells, microglia, and ependymal cells. Astrocytes form the framework of the brain and spinal cord (central nervous system) and form the blood–brain barrier. Ependymal cells form the epithelial lining of the central nervous system and produce cerebrospinal fluid. The oligodendrocytes are responsible for the development of myelin in the central nervous system. Schwann (neurilemma) cells produce myelin in the peripheral nervous system. Schwann cells also provide metabolic support. Schwann cell transplantation for therapeutic purposes is in a preclinical trial phase. Microglia have phagocytic activities. *Neurons: fundamental unit of the nervous system, generate bioelectrical impulses and transmit signals, do not have the ability to divide (unless they’re olfactory neurons). Neurons can take responsibility of other neurons if some were to die. In pns, severed nerves can regenerate and reestablish connections but in brain or spinal cord severed axons cannot be repaired leading to paralysis. Require constant oxygen and glucose. Have axons (transmit impulses away from cell body) and dendrites (transmit impulses toward cell body). When the axon reaches its destination, it often branches into several small fibers that terminate into miniscule bulges, called terminal boutons. These terminal boutons communicate with neurons, muscle fibers, or glands. Axons can communicate with several different