NU 545 Unit 2 Study Guide Questions and Answers.

NU 545 Unit 2 Study Guide Questions and Answers. 1. Review the anatomy of the brain. Which portion is responsible for keeping you awake, controlling thought, speech, emotions and behavior, maintaining balance and posture? P. 454-459 • Allows individuals to reason, function intellectually, express personality and mood and interact with environment  Approx. 3 lbs and consistency of tofu  15%-20% of total cardiac output  Midbrain, medulla oblongata and pons= brainstem  Collection of nuclei within the brainstem= reticular formation • Reticular Formation (regulates vital function- cardio and respiratory) essential for maintaining wakefulness  conjunction with cerebral cortex= reticular activating system • Prefrontal area- goal oriented behavior, short term/ recall memory, and elaboration of thought and inhibition on the limbic (emotional) areas of the CNS. • Broca Speech Area- responsible for motor aspects of speech (on left hemisphere) damage to this area as a result of CVA results in inability to form words (expressive aphasia and dysphasia) • Wernicke Area- superior temporal gyrus; responsible for reception and interpretation of speech • The Limbic System- primitive behavioral responses, visceral reaction to emotion, feeding behaviors, biologic rhythms, and sense of smell. Emotional and behavioral states= connections with the limbic system and prefrontal cortex • Cerebellum- responsible for conscious and unconscious muscle synergy-- for maintaining balance and posture. 2. Know the function of the arachnoid villi. P. 468 • Arachnoid villi— protrude from the arachnoids space, through dura mater, and lie within the blood flow of the venous sinuses. • CSF is reabsorbed by means of a pressure gradient btw the arachnoid vili and cerebral venous sinuses • Vili function as one way valves they direct CSF outflow into the blood but preventing blood from into the subarachnoid space. • Helps CSF circulate through the CNS and return to the blood 3. Where is the primary defect in Parkinsons disease and Huntingtons p. 457 • Defects of the basal ganglia • Various involuntary and exaggerated motor movements 4. What is the function of the CSF? Where is it produced? Where is it absorbed? P. 465 • Intracranial and spinal cord structures float in the CSF and are thereby partially protected from jolts and blows. 1 • Buoyant properties also prevent the brain from tugging on meninges, nerve roots and blood vessels. • *The choroid plexus in the lateral, third and fourth ventricles produce the major portion of CSF. • *The CSF does not accumulate but is reabsorbed into the venous circulation through the arachnoid vili primarily located superior to the falx cerebri in the superior sagittal sinus. 5. Review blood flow to the brain p. 467 • 800- 1000ml of blood flow per min • Carbon Dioxide (co2) is primarily regulator because it’s a powerful vasodilator that ensures adequate blood supply • 2 systems—internal carotid arteries & vertebral arteries • *carotid arteries= greater amount of blood flow • The arterial circle (circle of Willis) —ability to compensate for reduced blood flow from any one major contribution. • **formed by the posterior cerebral arteries, posterior communicating arteries, internal carotid arteries, anterior cerebral arteries, and anterior communicating artery. • Originate from the common carotid arteries, enter through the base of the skull and pass through the cavernous sinus divide into anterior and middle cerebral  arteries pass through the foramina of the cervical vertebrae enter cranium   through foramen magnum and Join at the junction of the PONS and MEDULLA OBLONGATA to form basilar artery, basilar artery divides at the midbrain to form paired posterior cerebral arteries 6. What is the gate control theory of pain? P. 485 • Integrates and builds upon features of other theories to explain the complex multidimensional aspects of pain perception and pain modulation. • modulated by a balance of impulses conducted to the spinal cord where cells in the substantia gelatiosa function as a “gate” • large myelinated A-delta fibers and small unmyleinated C fibers respond to a broad range of painful stimuli—these fibers terminate on interneurons in the substantia gelatinosa • Nociceptive transmission—“open” the spinal gate and increase perception of pain • Non-nociceptive Stimulation—closure or partial closure of the spinal gatesdecrease pain perception 7. Know the type of nerve fibers that transmit pain impulses. P. 486 • Nociceptors—free nerve endings that respond to specific stimuli; are categorized according to the stimulus to which they respond and by the properties of the axons associated with them.  A-delta Fibers—are lightly myelinated, medium sized- stimulated by severe mechanical deformation and or extreme temperatures. 1. Transmit sharp, well localized and fast pain sensations. 2 2. Cause reflex withdraw of affected body part BEFORE pain sensation is perceived  C- Fibers— unmyelinated, small- stimulated by mechanical, thermal and chemical nociceptors 1. Slowly transmit dull, aching or burning sensations that last longer  A-beta Fibers—large, myelinated fibers 1. transmit touch and vibration sensations 2. DO NOT normally transmit pain but play role in pain modulation 8. Where in the CNS does pain perception occur? • Pain Perception—conscious awareness of pain • Sensory-discriminative System— somatosensory cortex  Identifies the presence, character, location, and intensity of pain • Affective-motivational System— reticular formation, limbic system, and brainstem with projections to the prefrontal cortex  Determines individuals conditioned avoidance behaviors and emotional responses to pain. • Cognitive-eevaluative System—cerebral cortex  Overlies the individuals learned behavior concerning the experience of pain and can modulate perception of pain 9. Know different clinical descriptions of pain (acute, chronic, neuropathic); pain threshold/tolerance p. 491-495 • Acute Pain- protective mechanism that alerts the individual to a condition or experience that is immediately harmful to the body and mobilizes individual to take prompt action.  Lasts seconds to days and up to 3 months  Relieved after chemical mediators that stimulate pain receptors are removed  Stimulation of ANS increase HR, HTN, diaphoresis, dilated pupils   Acute somatic (superficial), Acute visceral (internal organs and lining of body cavities), Referred Pain (pain felt in an area removed or distant from its point of origin) • Chronic Pain- lasting at least three months and lasting well beyond the expected healing time following onset.  Serves no purpose and is poorly understood  Changes in peripheral and central nervous system cause dysregulation of nociception and pain modulation process that are thought to lead to chronic pain  Persistent pain allows for physiologic adaptation, producing normal heart rate and BP • Neuropathic Pain- results from pain injury to the peripheral or central nervous system and is not the result of pain signaling from peripheral organs or tissues  abnormal processing of sensory information by the PNS and CNS 3  Peripheral Neuropathic pain- peripheral nerve trauma; alcohol abuse, diabetics, HIV, carcinoma  Central Neuropathic pain- brain/ spinal cord trauma, tumors, MS, Parkinson’s, phantom limb pain, vascular lesions  Hemiagnosia Pain- central pain assoc with stroke that produces paralysis and hypersensitivity to one side of the body  Phantom Limb Pain- pain in an amputated limb/ stump after healed  Sympathetically Mediated Pain- peripheral nerve/ extremity damage- 1- 2wks after an extremity injury • Pain Threshold— the point at which a stimulus is perceived as pain, does not vary significantly among people or in the same person over times.  Intense pain at one location may increase threshold in another location • • Pain Tolerance—the duration of time or the intensity of pain that an individual will endure before initiating over pain responses.  Decreased with repeated exposure to pain  Influenced by culture, perceptions, expectations, role behaviors, physical and mental health, gender, fatigue, anger, boredom, apprehension and sleep deprivation  Tolerance may be INCREASED by: alcohol, persistent use of pain meds, hypnosis, warmth, distraction, and strong faith beliefs.