By A. Snorre. Franklin University.
The secretion of melatonin by the pineal gland is stimulated by sympathetic axons originating in the superior cervical ganglion buy sildenafil 100mg fast delivery medical erectile dysfunction pump. Activity of these neurons is regulated by the cyclic activity of the suprachiasmatic nucleus of the hypothalamus order 25mg sildenafil amex erectile dysfunction natural treatment reviews, which sets a circadian rhythm. They are also produced in the placenta, adrenal cortex, and even in the testes of the male. It Progesterone is produced by the corpus luteum and is pri- begins to regress in size at about the age of 7, and in the adult it marily associated with pregnancy in preparing the uterus for im- appears as a thickened strand of fibrous tissue. Although it lacks direct nervous connection to the rest of Most cultures of the world practice birth control, or contra- the brain, the pineal gland is highly innervated by the sympa- ception, in one form or another. It has a long history, dating back to the ancient Egyptians who used various substances to inhibit thetic division of the ANS from the superior cervical ganglion. In the age of hormonal biochemistry, The function of the pineal gland in some vertebrates is birth-control techniques have become increasingly sophisticated. Secretion of The female, rather than the male, has been the target of hormonal its principal hormone, melatonin, follows a circadian (daily) birth-control techniques for the following reasons: (1) ovulation is cyclic; (2) the genetic structure of each ovum is established by the rhythm tied to daily and seasonal changes in light. Melatonin is time of the female’s birth, whereas sperm production is a continuous thought to affect the hypothalamus by stimulating the secretion process, and therefore more vulnerable to genetic damage; (3) the of certain releasing factors (fig 14. These factors in turn female system has more potential sites for hormonal interference than does the male system; and (4) the female is usually more con- scientious about practicing birth control because she has far more invested in pregnancy than does the male. Endocrine System © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 476 Unit 5 Integration and Coordination affect the secretion of gonadotrophin and the ACTH from the adenohypophysis of the pituitary gland. Excessive melatonin se- Thyroid cartilage cretion in humans is associated with a delay in the onset of pu- of larynx berty; however the role of melatonin in sexual maturation is still highly controversial. Although the size of the thymus varies Thymus considerably from person to person, it is relatively large in new- borns and children and then sharply regresses in size after pu- berty. Besides decreasing in size, the thymus of adults becomes Left lung infiltrated with strands of fibrous and fatty connective tissue. The principal function of the thymus is associated with the lymphatic system (see chapter 16) in maintaining body immu- nity through the maturation and discharge of a specialized group of lymphocytes called T cells (thymus-dependent cells). The thy- mus also secretes a hormone called thymosin, which is believed to stimulate the T cells after they leave the thymus. Endocrine System © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 Developmental Exposition velopment of the testes and ovaries is discussed in chapters 20 The Endocrine System and 21, respectively. Pituitary Gland EXPLANATION Although the pituitary gland is a single organ, it is actually com- The endocrine system is the only anatomical body system whose posed of two distinct types of tissues that have different embry- organs are not structurally connected. These two types of tissues release different hormones isolated from each other and are distributed throughout the body, and are under different control systems. The anterior portion of each endocrine organ has a separate and independent develop- the hypophysis, called the adenohypophysis, develops from ecto- ment. All three embryonic germ layers (endoderm, mesoderm, derm that lines the primitive oral cavity. The posterior portion, and ectoderm) contribute to the development of the endocrine called the neurohypophysis, develops from neuroectoderm of the system. The following sections describe, in turn, the development The adenohypophysis begins to develop during the fourth of the pituitary, thyroid, pancreas, and adrenal glands. The de- week as a diverticulum, a pouchlike extension, called the EXHIBIT I The development of the pituitary gland. The pituitary gland arises from a specific portion of the neuroectoderm, called the neurohy- pophyseal bud, which evaginates downward during the fourth and fifth weeks respectively in (b) and (c), and from a specific portion of the oral ectoderm, called the hypophyseal (Rathke’s) pouch, which evaginates upward from a specific portion of the primitive oral cavity. At 8 weeks (d), the hypophyseal pouch is no longer connected to the pharyngeal roof of the oral cavity. During the fetal stage (e), the develop- ment of the pituitary gland is completed. Endocrine System © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 (concluded) hypophyseal (Rathke’s) pouch. At this time, the thyroglossal duct disappears and primitive oral cavity and grows toward the brain. At the same the foramen cecum regresses in size to a vestigial pit that persists time, another diverticulum called the infundibulum forms from throughout life. As the two diverticula come in contact, the hypophyseal pouch loses its con- Pancreas nection with the oral cavity, and the primordial tissue of the ade- The pancreas begins development during the fifth week, as dorsal nohypophysis is formed. The fully developed adenohypophysis and ventral pancreatic buds of endoderm arise from the caudal includes the pars distalis and the pars tuberalis.
Drinking an adequate amount of fluid at one sitting will gener- ally result in an urge to void within the retraining time frame buy sildenafil 75 mg without prescription 2010 icd-9 code for erectile dysfunction. Avoiding fluids with caffeine discount sildenafil 25 mg on-line erectile dysfunction drugs and heart disease, artificial sweeteners, and alcohol will reduce bladder irritability. Medications that are beneficial for failure to store and DSD include: anticholinergics (oxybutynin) antimuscarinics (tolterodine tartrate, hyoscyamine sulfate) tricyclic antidepressants (imipramine) antidiuretic hormone analog (desmopressin acetate), particularly for nocturia C. Crede method is contraindicated because of the potential to create increased pressure and damage the upper tract. Allows an individual to empty the bladder at regular intervals, thereby reducing the risk of UTI, structural damage, and other distressing bladder symptoms. Teaching guides are available 74 NURSING PRACTICE IN MULTIPLE SCLEROSIS: A CORE CURRICULUM E. An indwelling catheter may be needed for either short- or long-term use and allows for continual drainage by gravity. Its use is suggested for those individuals who cannot be managed with ISC and/or medications, or who have chronic decubiti and cannot perform ISC. Long-term use of indwelling catheters is a significant source of bacteruria and UTI. Management varies but the usual practice is to change the catheter after a minimum of 30 days or prn. If the patient has a symptomatic UTI, the entire system must be changed and a urine culture obtained. A person with MS may still experience urinary incontinence with an indwelling catheter. In this instance, the indication is not to increase the size of the catheter or balloon, but rather to use anticholinergic/antimuscarinic medications to decrease urinary tract spasticity. Suprapubic catheters are sometimes an alternative to long-term urethral catheters. These may be helpful in male patients and in women who have developed severe urethral irritation secondary to an indwelling Foley catheter. Sphincterectomy may be recommended for very disabled male patients who experience intractable hesitancy and retention. Anticholinergic medications and an external condom catheter can be combined to manage bladder activity. Some female patients with small-capacity bladder may benefit from a laparoscopic procedure that includes bladder augmenta- tion with a continent diversion. Diversion procedures including cystostomy or transurethral resection, which provides a clear passageway for the urine to flow freely. Chapter 14 Bowel Elimination and Continence Objectives: Upon completion of this chapter, the learner will identify: The common pathophysiology of upper motor neuron bowel, lower motor neuron bowel, uninhibited neurogenic bowel, and motor paralytic bowel as seen in MS Goals for establishing bowel control with MS Common nursing interventions in managing a neurogenic bowel A comprehensive care plan for gastrointestinal complications The long-term implications of neurogenic bowel dysfunction Altered bowel function may occur whenever the central nervous system (CNS) has been impaired. When disease or disability results in altered bowel control, incontinence may become as devastating a problem as the disease itself. Control of incontinence and prevention of constipation and diarrhea are possible through an effective bowel program, which requires a knowledge of normal and altered bowel physiology as well as an in-depth assessment of bowel function. The lower bowel acts under voluntary control to store and eliminate feces. Inability to store fecal matter causes problems with involuntary bowel or incontinence. The bowel consists of three separate parts: the ileum, the cecum, and the colon. It is approximately 12 feet long and extends from the jejunum to the ileocecal opening. Almost all absorption and digestion is accomplished in the small intestine. The small intestine absorbs water and sodium and secretes mucus, potassium, and bicarbonate for stool formation.
There are thought to be some common nerve pathways that are Proprioceptors used by sensory impulses coming from both the cutaneous areas Proprioceptors monitor our own movements (proprius means “one’s and from visceral organs (fig buy cheap sildenafil 50 mg line erectile dysfunction blogs. Consequently purchase sildenafil 25 mg visa erectile dysfunction after radical prostatectomy treatment options, impulses own”) by responding to changes in stretch and tension, and by along these pathways may be incorrectly interpreted as arising transmitting action potentials to the cerebellum. Acute pain is sory impulses from proprioceptors reach the level of consciousness as sudden, usually short term, and can generally be endured and attrib- uted to a known cause. Chronic pain, however, is long term and the kinesthetic sense, by which the position of the body parts is per- tends to weaken a person as it interferes with the ability to function ceived. Certain diseases, such as arthritis, are characterized by the limbs can be determined without visual sensations, such as when chronic pain. In these patients, relief of pain is of paramount con- dressing or walking in the dark. Treatment of chronic pain often requires the use of moderate pain-reducing drugs (analgesics) or intense narcotic drugs. Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 Chapter 15 Sensory Organs 493 FIGURE 15. Pain originating from the myocardium of the heart may be perceived as coming from the skin of the left arm because sensory impulses from these two organs are conducted through common nerve pathways to the brain. Proprioceptors are located in and around synovial joints, in Neural Pathways for Somatic Sensation skeletal muscle, between tendons and muscles, and in the inner ear. They are of four types: joint kinesthetic receptors, neuromus- The conduction pathways for the somatic senses are shown in cular spindles, neurotendinous receptors, and sensory hair cells. Sensations of proprioception and of touch and pres- sure are carried by large, myelinated nerve fibers that ascend in • Joint kinesthetic receptors are located in synovial joint the posterior columns of the spinal cord on the ipsilateral (same) capsules, where they are stimulated by changes in body po- side. These fibers do not synapse until they reach the medulla sition as the joints are moved. They consist of the medulla oblongata with second-order sensory neurons, informa- endings of sensory neurons that are spiraled around special- tion in the latter neurons crosses over to the contralateral (oppo- ized individual muscle fibers (fig. Third-order sensory caused by the lengthening or stretching of the individual neurons in the thalamus that receive this input in turn project to fibers, and thus provide information about the length of the postcentral gyrus in the cerebral cortex. Sensations of heat, cold, and pain are carried by thin, un- • Neurotendinous receptors (Golgi tendon organs) are lo- myelinated sensory neurons into the spinal cord. They within the spinal cord with second-order association neurons that are stimulated by the tension produced in a tendon when cross over to the contralateral side and ascend to the brain in the the attached muscle is either stretched or contracted. Fibers that mediate touch and pres- • Sensory hair cells of the inner ear are located in a fluid- sure ascend in the ventral spinothalamic tract. Fibers of both filled, ductule structure called the membranous labyrinth. Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 494 Unit 5 Integration and Coordination Extrafusal fibers Intrafusal fibers: Nuclear chain fibers Skeletal muscle Nuclear bag fiber Peripheral nerve (Motor and sensory neurons) Connective tissue sheath Muscle Sensory neurons spindle Sensory neuron Neurotendinous receptors Motor neurons Tendon Bone Motor end plates (a) (b) FIGURE 15. Also, because of decussation (crossing- over), somatic information from each side of the body is projected Knowledge Check to the postcentral gyrus of the contralateral cerebral hemisphere. List the different types of cutaneous receptors and state All somatic information from the same area of the where they are located. What portion of the brain inter- body projects to the same area of the postcentral gyrus. List the receptors that that receive sensory information from different parts of the body respond to pain and the structures of the brain that (see fig. Such a map is greatly distorted, however, be- are particularly important in the perception of pain cause it shows larger areas of cerebral cortex devoted to sensation sensation. The dis- proportionately large areas of the caricature-like sensory ho- 8. Discuss why it is important for a physician that there is a higher density of sensory receptors in the face and to know the referred pain sites. Using a flow chart, describe the neural pathways leading from cutaneous pain and pressure receptors to the postcen- tral gyrus. Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 Chapter 15 Sensory Organs 495 FIGURE 15. Olfac- tion functions closely with gustation (taste) in that the receptors Olfactory receptors are the dendritic endings of the olfactory nerve for both are chemoreceptors, which require dissolved substances (I) that respond to chemical stimuli and transmit the sensation of for stimuli. Olfactory receptor cells are located in the nasal mucosa within the roof of the nasal cavity on both sides of the nasal sep- Objective 8 Describe the sensory pathway for olfaction.
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