NU 545 Exam 2 Study Questions with Detailed Answers (Expert Graded A+)

NU 545 Exam 2 Study Questions with Detailed Answers (Expert Graded A+) 1. Anatomy of the brain: Forebrain (Prosencephalon)- General - ANSWER Cerebrum- largest portion -Includes the telencephalon (cerebral hemispheres) made of the cerebral cortex and basal ganglia -Divided into 4 lobes: frontal, parietal, occipital, and temporal -Lobes are divided by fissures (Sulci —gyri: greatly increase surface area — fissures) -Includes the diencephalon (central structures) aka interbrain 2. Anatomy of the brain: Forebrain (Prosencephalon)- Hemispheres - ANSWER Hemispheres (Telencephalon) · Separated by the longitudinal fissures · Every person has 1 dominant hemisphere · Connected by Corpus Callosum (aka: transverse commissural fissure) 3. What type of nerve fibers transmit pain impulses? (Ch.16 pp 470) - ANSWER Primary-order neurons i. Myelinated A-delta fibers - fast and cause reflex withdrawal; stimulated by mechanical and thermal receptors; conveys sharp, localized ii. Unmyelinated C fibers- slower- stimulated by mechanical, thermal, and chemical receptors; conveys diffuse burning and aching sensation iii. A- beta fibers- transmit touch and vibration sensation; do not normally transmit pain but play a role in the pain modulation. 4. ·A delta and C fibers comprise the primary first-order sensory afferents coming into the gate at the dorsal horn of spinal cord à second-order neurons cross the cord and ascend to the thalamus as part of the spinothalamic tract à third order afferents project to higher brain centers of the limbic system, frontal cortex, and primary sensory cortex of the postcentral gyrus of the parietal lobe 5. The gray matter of the spinal cord is divided into 3 regions (Ch.15 pp 448) i. Posterior/dorsal horn: (sensory) axons from sensory neuros whose cell bodies lie in the dorsal root ganglion (Substantia gelatinosa at the tip- involved in pain transmission) ii. Lateral horn: (ANS) cell bodies involved with the ANS iii. Anterior/ventral horn: (motor) contains nerve cell bodies for efferent pathways (motor) 6. Where in the CNS does pain perception occur? (ch. 16, pp 470) - ANSWER Afferent pathways: start in PNS, travel to the spinal gate in the dorsal horn, and then ascend to higher centers in CNS 7. Interpretive centers- located in the brainstem midbrain, diencephalon, and cerebral cortex i. Thalamus cortex, and postcentral gyrus perceive, describe, and localize pain ii. Reticular formation and limbic system control the emotional and affective response to pain iii. Perception of pain: brainstem reticular formation, thalamus, limbic systems and the cerebral cortex (somatosensory cortex) Efferent pathways- descend from the CNS to the dorsal horn of the spinal cord Pain facilitators: glutamate, substance P, histamine, prostaglandin, bradykinin Pain inhibitors: Opioids, GABA, cannabinoids, serotonin, norepi 8. Know different clinical descriptions of pain (acute, chronic, neuropathic); (Ch. 16 pp 373) - ANSWER Neurophysiologic i. Nociceptive Pain (acute)- pain with normal tissue injury from a known cause Somatic: superficial from joints, muscles, bone and skin; well localized Visceral: internal from organ and lining of body cavities; poorly localized Referred: pain in area is removed or distant from its point of origin ii. Neuropathic pain/Nonnociceptive Pain- results form nerve trauma/dz Usually chronic pain initiated or caused by a primary lesion or dysfxn in nervous system leading to long-term changes in pain pathways and abnormal processing of sensory information Peripheral: injured nerves become hyperexcitable in the PNS Central: a lesion or neuroplastic changes in the brain or spinal cord Includes: phantom limb pain (regeneration/hyperactivity of injured/cute peripheral nerves), central poststroke pain (hypersensitivity on one half of body), and complex regional pain syndrome (CRPS) (associated with limb injury, types I and II) Neurogenic Pain iii. Neuralgia: pain in the distribution of a nerve iv. Constant: sympathetically independent or dependent Temporal Pain v. Acute vi. Chronic Pain- more than 3-6 months · Regional: abdomen, chest, HA, low back, pelvic, joint, orofacial Etiology Pain i. Cancer, dental, inflammatory, ischemic, vascular, postoperative 9. Know different clinical descriptions of pain: pain threshold/tolerance (Ch. 16 pp 373) - ANSWER · Pain threshold: point pain is perceived- lowest intensity of pain that a person can recognize; intense pain at one location may increase the threshold in another location · Pain tolerance: the greatest intensity of pain that a person can endure; varies greatly among people and in the same person over time (decreases) 10.Know endogenous opioids (ch. 16 pp 473) - ANSWER · Family of morphine-like peptides that inhibit transmission of pain impulses in the spinal cord, brain, and periphery. 4 types: i. Enkephalins- most prevalent; bind to delta opioid receptors; concentrated in the hypothalamus, PAG matter, the medulla, and the dorsal horns ii. Endorphins- (endogenous morphine)- produced in the brain, beta endorphin binds to mu receptors in the hypothalamus and pituitary gland and is purported to produce the greatest sense of exhilaration as well as substantial natural pain relief iii. Dymorphins- most potent; binds stongly with kappa receptors to impede pain signals in the brain. Play a role in mood disorders and drug addiction and paradoxically in stimulating chronic pain. iv. Endomorphins- 1 and 2 bind with mu receptors throughout the brain, brainstem, and GI tract and have analgesic and anti-inflammatory effects 11.What is the relationship between epi and body temp (ch. 16 pp 478) - ANSWER Heat producing mechanism i. TSH-RH -- stimulated the anterior pituitary to release TSH -- acts on the thyroid gland and stimulates release of thyroxine -- acts on the adrenal medulla causing the release of epi -- causes vasoconstriction, stimulates glycolysis, and increases metabolic rate, thus increasing body head. ii. Norepi and thyroxine activate brown fat thermogenesis, where energy is released as heat instead of as ATP.