By N. Bandaro. University of South Dakota. 2017.

It is often necessary in the critical care his knee baclofen 10mg overnight delivery, across the back of his elbow generic 25 mg baclofen, administration of fluids and medications. Nervous Tissue and the © The McGraw−Hill Anatomy, Sixth Edition Coordination Central Nervous System Companies, 2001 Nervous Tissue and the Central Nervous System 11 Organization and Functions of the Nervous System 344 Developmental Exposition: The Brain 346 Neurons and Neuroglia 348 Transmission of Impulses 357 General Features of the Brain 358 Cerebrum 363 Diencephalon 372 Mesencephalon 373 Metencephalon 374 Myelencephalon 376 Meninges 378 Ventricles and Cerebrospinal Fluid 381 Spinal Cord 384 Developmental Exposition: The Spinal Cord 390 CLINICAL CONSIDERATIONS 391 Clinical Case Study Answer 396 Chapter Summary 397 Review Activities 398 Clinical Case Study A 56-year-old woman visited her family doctor for evaluation of a headache that had persisted for nearly a month. Upon questioning the patient, the doctor learned that her left arm, as she put it, “was a bit unwieldy, hard to control, and weak. He also found weakness, al- though less significant, of the left lower extremity. Sensation in the limbs seemed to be normal, although mild rigidity and hyperactive reflexes were present. Expressing concern, the doctor told the patient that she needed a CT scan of her head, and explained that there could be a problem within the brain, possibly a tumor or other lesion. After explaining the patient’s case, the doctor remarked parenthetically that he believed he knew where the problem was located. Why did the doctor suggest to the patient that there might be a problem within her brain when the symptoms were weakness of the extremities, and then just on one side of her body? Explain the muscle weakness in terms of neuronal path- ways from the brain to the periphery. FIGURE: Improvements in radiographic imaging have greatly enhanced the Hints: Remember the controlling and integrating function of the brain. Carefully study the in- visualization of anatomical structures, and are formation and accompanying figures concerning the structures and functions of the brain and indispensable aids to diagnostic medicine. Nervous Tissue and the © The McGraw−Hill Anatomy, Sixth Edition Coordination Central Nervous System Companies, 2001 344 Unit 5 Integration and Coordination with the endocrine system, regulates the functions of the other ORGANIZATION AND FUNCTIONS body systems. The brain, however, does much more than that— OF THE NERVOUS SYSTEM and its potential is perhaps greatly underestimated. It is incompre- hensible that one’s personality, thoughts, and aspirations result The central nervous system and the peripheral nervous system from the functioning of a body organ. Plato referred to the brain are structural components of the nervous system, whereas the as “the divinest part of us.

The single active X chromosome of the sper- mologous to inhibin and transforming growth factor order baclofen 10mg with visa, matogonium becomes inactivated during meiosis generic baclofen 10mg with amex, and a which inhibits cell division of the müllerian ducts. The sec- functional X chromosome is not necessary for the forma- ond is androgen-binding protein (ABP), which binds tion of fertile sperm. Peak production of these compounds occurs its second X chromosome, and both are functional in between weeks 9 and 12, coinciding with the time of dif- oocytes and important for normal oocyte development. Testicular differentiation requires a Y chromosome and The ovary, which differentiates later, does not produce occurs even in the presence of two or more X chromo- hormones and has a passive role. Gonadal sex determination is regulated by a testis- The primordial external genitalia include the genital tu- determining gene designated SRY (sex-determining region, bercle, genital swellings, urethral folds, and urogenital si- Y chromosome). Differentiation of the external genitalia also occurs mosome, SRY encodes a DNA-binding protein, which between weeks 8 and 12 and is determined by the presence binds to the target DNA in a sequence-specific manner. Differentiation along The presence or absence of SRY in the genome determines the male line requires active 5 -reductase, the enzyme whether male or female gonadal differentiation takes place. Without DHT, re- Thus, in normal XX (female) fetuses, which lack a Y chro- gardless of the genetic, gonadal, or hormonal sex, the ex- mosome, ovaries, rather than testes, develop. The Whether possessing the XX or the XY karyotype, every structures that develop from the primordial structures are embryo goes initially through an ambisexual stage and has illustrated in Figure 39. A 4- to 6-week-old human embryo possesses in- gen-dependent differentiation occurs only during fetal life different gonads, and undifferentiated pituitary, hypothal- and is thereafter irreversible. Testicular descent into the rived from coelomic epithelium and underlying mes- scrotum, which occurs during the third trimester, is also enchyme, and primordial germ cells, which migrate from controlled by androgens. In many species, a sharp decline in the circulating levels of progesterone and The duration of pregnancy in women averages 270 14 a concomitant rise in estrogen precede birth. Parturition or the onset progesterone does not fall significantly before delivery.

Retraining too rapidly or too soon after an injury or re- age directly related to the contractile function of muscle is turning to activity too soon also make reinjury more likely discount baclofen 25 mg amex. Such injuries are incidental to the muscle’s Delayed-onset muscle soreness buy discount baclofen 10mg, as often experienced primary function of exerting force and causing motion. In after unaccustomed exercise, also results from strain in- the areas of sports or physical labor, muscle strain is the jury, but on a smaller scale. The pain peaks 1 to 2 days gastrocnemius or the rectus femoris) or that have a com- after exercise; as the healing progresses, the muscle be- plex architecture (e. Often the injury will be confined to one bouts of exercise are tolerated increasingly well and are muscle of a group used to perform a specific action. Injury associated with the hypertrophy of the muscle; hence, the can occur to a muscle that is overstretched while unstimu- familiar phrase, “No pain, no gain. They include the application of ice packs and enforced rest Under such circumstances, the force in the muscle may of the injured muscle. Nonsteroidal anti-inflammatory rise to a level considerably higher than could be attained in drugs (NSAIDs) can lessen the pain, but they also appear an isometric contraction; relatively few injuries occur un- to delay healing somewhat. For injuries in which an actual der isometric or isotonic (concentric) contraction condi- separation of the muscle and tendon occurs, surgical re- tions. Massaging of an injured muscle does not junction, a location that can be determined by physical ex- appear to be as beneficial as light exercise, which may help amination and confirmed by magnetic resonance imaging to increase blood flow and promote healing. There may from strain injury is associated with the gradual regaining also be extensive damage throughout the muscle itself. In of strength, which will eventually reach near-normal levels some cases, there is complete disruption of the muscle if reinjury is avoided. Some muscle tissue is permanently (avulsion), although usually separation is not complete. Most recovered muscles will have a some- ness, weakness, delayed swelling, and “bunching up” in what increased susceptibility to injury for an extended pe- extreme cases. Several predisposing factors may cause a muscle strain Precautions for avoiding strain injury include adequate injury, including relative weakness of a given muscle, result- physical conditioning and practiced expertise at the task at ing from a lack of training early in a sports season, and fa- hand. Preexercise stretching and warm-up may be of some tigue, which leads to increased injury late in an athletic value in preventing strain injury, although the experimen- event.