NURS 5315 Advanced pathophysiology -Neurologic System Module 7 2021 latest edited study guide

N5315 Advanced Pathophysiology Neurologic System Module 7 Examine the anatomy and physiology of the Central Nervous System. 1. Discuss the anatomy and physiology of the brain and brain stem. a. Explain the function of the twelve cranial nerves I – Olfactory (Smell) Function: Sensory, carries impulses for sense and smell Sign of Dysfunction: Loss or disturbance in the sense of smell. II – Optic (Sight) Function: Sensory, carries impulses for vision Sign of Dysfunction: decreased visual acuity and contrast sensitivity, impaired color vision, and an afferent pupillary defect. (blindness) III – Oculomotor Function: Contains motor fibers to interior oblique and to superior, inferior, ad medial rectus extraocular muscles that direct eye ball; levator muscles of eyelid; smooth muscles of iris and ciliary body; and proprioception (sensory) to brain from extraocular muscles Sign of Dysfunction: Drooping of the eyelid, eyeball moves outward, dilation of the pupil, double vision. IV – Trochlear Function: Propioceptor and motor fibers for superior oblique muscle of eye (extraocular muscles) Sign of Dysfunction: Rotation of eyeball upward and outward, double vision V Trigeminal (facial muscles including chewing, facial sensation) This is the largest cranial nerve Function: Both motor and sensory for face; conducts sensory impulses from mouth, nose, surface of eye, and dura mater; also contains motor fibers that stimulate chewing muscles Sign of Dysfunction: Sensory root – Pain or loss of sensation in the face, forehead, temple and eyes. Motor root – affecting the jaw, trouble chewing VI Abducens (moves eyeballs) Function: Moves the eyeballs outwards by sending nerve impulses to the lateral rectus muscles Sign of Dysfunction: Deviation of the eyes outward; double vision VII Facial (taste, tears, saliva and facial expressions) Function: Mixed: 1. Supplies motor fibers to muscles of facial expression and to the lacrimal and salivary glands. 2. Carries sensory fibers from taste buds of anterior part of tongue Sign of Dysfunction: Paralysis of all the muscles in one side of the face, inability to wrinkle the forehead, close the eye, whistle, deviation of the mouth. Bell’s Palsy VIII Vestibulocochlear (acoustic) auditory Function: Purely sensory; vestibular branch transmits impulses for sense of equilibrium, cochlear branch transmits impulses for sense of hearing Sign of Dysfunction: Deafness or ringing in the ears, dizziness, nausea and vomiting IX Glossopharyngeal (swallowing, saliva, taste) Function: Mixed: 1. Motor fibers serve pharynx and salivary glands. 2. Sensory fibers carry impulses from, pharynx, posterior tongue, and pressure receptor of carotid artery (blood pressure) Sign of Dysfunction: Disturbance of taste; Difficulty in swallowing X Vagus (control of PNS: smooth muscles of GI tract) Function: Sensory and motor impulses for pharynx; a large part of this nerve is parasympathetic motor fibers, which supply smooth muscles of abdominal organs Sign of Dysfunction: Hoarseness and difficulty swallowing and talking. This nerve also regulates the heart, blood vessels and digestion resulting in irregular heartbeat and lowered blood pressure. It regulates the stomach telling it to move food through the digestive system, thus damage can result in decreased digestion and thus nausea, bloating and vomiting. XI Spinal accessory (moving of head and shoulders, swallowing) Function: Provides sensory and motor fibers for sternocleidomastoid and trapezius muscles (movement of head and shoulders) and muscles of soft palate, pharynx, and larynx (swallowing) Sign of Dysfunction: Dropping of the shoulder; inability to rotate the head away from affected area. XII Hypoglossal (tongue muscles, speech and swallowing) Function: Carries motor fibers to muscles of tongue and sensory impulses from tongue to brain. Sign of Dysfunction: Paralysis of one side of the tongue; deviation of tongue toward paralyzed side; thick speech. b. Explain the function of the cerebrum, cerebellum, parietal lobe, frontal lobe, occipital lobe, temporal lobe, brain stem, reticular formation reticular activating system, and limbic system. Location: forebrain Cerebrum Largest part of the bain. Derived from the telencephalon, characterized by numerous convolutions called gyri. Comprised of two hemispheres Contain- cerebral cortex, basal ganglia, epithalamus, thalamus, hypothalamus, subthalamus. Prefrontal lobe- goal-oriented behavior/concentration, short-term memory, elaboration of thought and inhibition on the limbic areas of the CNS. Prefrontal (Brodmann 6) programming motor movements. Basal ganglia system- extrapyramidal system- efferent pathways outside the pyramids of the medulla. Frontal eye fields (lower portion of Brodmann 8) controlling eye movement in the middle frontal gyrus. Function: Divided into numerous smaller areas which are each dedicated to specific areas of function. These areas include frontal lobe, parietal lobe, temporal lobe and occipital lobe Basal ganglia- fine tuning of motor movement. Cerebral cortex has contralateral control of the body. Sign of Injury/Lesion/Disorder: Dependent on location, see below Parkinson’s, Huntington disease- basal ganglia Cerebral cortex has contralateral (opposite side) control of the body. Location: Frontal Anterior portion of the brain encompassing from the frontal part of the skull to the central sulcus of the brain Function: Include prefrontal which is responsible for goal oriented behavior, short term memory, elaboration of thought and inhibition of limbic system. Includes the premotor area which is involved in movements, includes the neurons contributing to the extrapyramidal system or basal ganglia. Frontal lobe also includes primary motor area which forms a somatic organization referred to as a homunculus (little man). Also includes Broca’s area, responsible for speech Sign of Injury/Lesion/Disorder: Damage to the frontal will manifest itself significant to the area of the injury. For example, damage to the Broca area from CVA will cause difficulty in forming words Location: Temporal Makes up the lower portion of the brain, just above the pons/cerebellum and spans L and R hemispheres. Lies inferior to the lateral sulcus, composed of superior, middle, and inferior temporal gyri. Function: Primary auditory cortex (Brodmann area 42 and associated area 42) lie deep within the lateral sulcus of the superior temporal gyrus. Wernicke area (posterior portion of Brodmann area 22) – superior temporal gyrus- interpretation of speech, dysfunction = receptive aphasia or dysphasia. Major area for long-term memory and balance, taste, smell. Epileptic loci often found in the temporal lobe. Sign of Injury/Lesion/Disorder: Parietal Location: Forebrain: Lies within border of the central, parietooccipital and lateral sulci Function: Somatic sensory input. Communication between motor and sensory areas Sign of Injury/Lesion/Disorder: Occipital Location: Forebrain: Caudal to the pareitococcipital sulci and superior to the cerebellum Function: Visual cortex Sign of Injury/Lesion/Disorder: Location: Hindbrain: Cerebellum Function: Responsible for conscious and unconscious muscle synergy . Maintaining balance and posture Sign of Injury/Lesion/Disorder: Damage causes ipsilateral loss of equilibrium, balance, motor coordination. (has ipsilateral control of the body). Location: Brain Stem (midbrain, medulla oblongata, and pons) Located at the base of the brain Function: Medulla: regulate breathing and blood pressure, swallowing, coughing and vomiting reflexte Pons: balance and maintainence of posture and regulation of breathing. Relays information from cerebral hemispheres to teh cerebellum Midbrain: control of eye movements and visual systems Sign of Injury/Lesion/Disorder: Loss of function- breathing, regulate BP, protective reflexes for airway Location: Reticular Formation and Reticular Activating System Brainstem: A collection of nuclei within the brainstem p454 (reticular formation in conjuction with the cerebral cortex is referred to as the Reticular Activating System) Function: maintaining wakefulness Maintains vital reflexes ( cardiovascular function and respiration Sign of Injury/Lesion/Disorder: Alterations in consciousness Location: Limbic System Forebrain: Composed of Papez circuit – (amygdala, parahippocampal gyrus, hippocampus, fornix, mammillary body of the hypothalamus, thalamus, cingulate gyrus), septal area, habenula, nucleus accumbens, other portions of the hypothalamus, related autonomic nuclei. Function: Consolidation of memory, Extension of olfactory system. Primitive behavioral responses, visceral reaction to emotion, feeding behaviors, biologic rhythms, and sense of smell Basic emotion area – fear, pleasure, anger, and drives (hunger, sex, dominance, care of offspring). Primitive behavioral responses, visceral reaction to emotion, feeding behaviors, biologic rhythms, sense of smell. A major function is consolidation of memory through a reverberating circuit. Sign of Injury/Lesion/Disorder: c. Identify which area of the brain is impacted