By A. Fabio. Franklin University.
If the right wrist or hip ness) is an abnormal lateral curvature of the vertebral column develops the disease 500mg antabuse mastercard, so does the left. It may be caused by abnormal vertebral structure, un- Osteoarthritis is a degenerative joint disease that results equal length of the legs, or uneven muscular development on the from aging and irritation of the joints. Articulations © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Chapter 8 Articulations 227 (a) FIGURE 8. In this technique, a needlelike viewing arthroscope is threaded into the joint capsule through a tiny incision. The arthroscope has a fiberoptic light source that illuminates the inte- rior of the joint. Thus, the position of the surgical instruments that may be inserted through other small incisions can be seen. Gouty arthritis results from a metabolic disorder in which an abnormal amount of uric acid is retained in the blood and sodium urate crystals are deposited in the joints. The salt crystals irritate the articular cartilage and synovial membrane, causing swelling, tissue deterioration, and pain. Males have a greater incidence of gout than females, and apparently the disease is genetically determined. Arthroscopic inspection involves making a small incision into the joint cap- damaging. Osteoarthritis is a progressive disease in which the ar- sule and inserting a tubelike instrument called an arthroscope. The affected In arthroscopy of the knee, the articular cartilage, synovial joints seldom swell, and the synovial membrane is rarely dam- aged. As the articular cartilage deteriorates, ossified spurs are de- posited on the exposed bone, causing pain and restricting the movement of articulating bones. Osteoarthritis most frequently affects the knee, hip, and intervertebral joints. Articulations © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 228 Unit 4 Support and Movement (a) (b) (c) (d) FIGURE 8.
Every individ- The exposed surface of the skin has recognizable patterns that ual’s prints are unique order 500mg antabuse with mastercard, including those of identical twins. All other primates have ridges) are congenital patterns that are present on the finger and fingerprints, and even dogs have a characteristic “nose print” that is toe pads, as well as on the palms and soles. The designs formed used for identification in the military canine corps and in certain dog kennels. They are formed by the pull of elastic fibers within the dermis and are well established prenatally. The Dermis ridges of fingerprints function to prevent slippage when grasping objects. Because they are precise and easy to reproduce, finger- The dermis is deeper and thicker than the epidermis (see prints are customarily used for identifying individuals. Elastic and collagenous fibers within the dermis are arranged in definite patterns, producing lines of tension in the skin and providing skin tone (fig. Integumentary System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Chapter 5 Integumentary System 111 FIGURE 5. Stretch marks generally fade with time but may leave permanent markings. Innervation of the Skin The dermis of the skin has extensive innervation (nerve supply). Specialized integumentary effectors consist of smooth muscles or glands within the dermis that respond to motor impulses trans- mitted from the central nervous system to the skin by autonomic FIGURE 5. Surgical incisions Several types of sensory receptors respond to various tactile made parallel to the lines of tension heal more rapidly and create less (touch), pressure, temperature, tickle, or pain stimuli.
Mechanorecep- tors in the rectum detect distension and supply the enteric neural circuits with sensory information buy cheap antabuse 500 mg, similar to the in- The Descending Colon Is a Conduit Between nervation of the upper portions of the GI tract. Unlike the the Transverse and Sigmoid Colon rectum, the anal canal in the region of skin at the anal verge Radioscintigraphic studies in humans show that feces do is innervated by somatosensory nerves that transmit signals not have long dwell-times in the descending colon. This region has sensory receptors that detect beled feces begin to accumulate in the sigmoid colon and touch, pain, and temperature with high sensitivity. Pro- rectum about 24 hours after the label is instilled in the ce- cessing of information from these receptors allows the in- cum. The descending colon functions as a conduit without long-term retention of the feces. Activation of the program is responsible for mass movements of feces into the sigmoid Symphysis pubis colon and rectum. Left pubic tubercle The Physiology of the Rectosigmoid Region, Anal Canal, and Pelvic Floor Musculature Maintains Fecal Continence The sigmoid colon and rectum are reservoirs with a capac- ity of up to 500 mL in humans. Distensibility in this region is an adaptation for temporarily accommodating the mass Rectum Puborectalis muscle movements of feces. The rectum begins at the level of the Anorectal angle third sacral vertebra and follows the curvature of the sacrum and coccyx for its entire length. It connects to the Anal canal anal canal surrounded by the internal and external anal sphincters. The pelvic floor is formed by overlapping sheets of striated fibers called levator ani muscles. This Anus muscle group, which includes the puborectalis muscle and FIGURE 26. These skeletal muscles be- borectalis muscle inserts on the left pubic tubercle, and the other have in many respects like the somatic muscles that main- inserts on the right pubic tubercle, forming a loop around the tain posture elsewhere in the body (see Chapter 5). Contraction of the pub- The pelvic floor musculature can be imagined as an in- orectalis muscle helps form the anorectal angle, believed to be verted funnel consisting of the levator ani and external important in the maintenance of fecal continence. In addition, Muscles in the Large Intestine and Pelvic Floor stretch receptors in the muscles of the pelvic floor detect Distension of the rectum by the mass movement of feces or changes in the orientation of the anorectum as feces are gas results in an urge to defecate or release flatus.