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STUDENT DIGITAL NEWSLETTER ALAGAPPA INSTITUTIONS |
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Contains the superficial transverse perineal muscle 97110 treatment code order phenytoin 100 mg on-line, the ischiocavernosus muscles and crus of the penis or clitoris medications you can give dogs phenytoin 100mg low cost, the bulbospongiosus muscles and the bulb of the penis or the vestibular bulbs treatment viral pneumonia trusted phenytoin 100mg, the central tendon of the perineum symptoms xanax withdrawal phenytoin 100mg without prescription, the greater vestibular glands (in the female) symptoms you have cancer cheap 100mg phenytoin free shipping, branches of the internal pudendal vessels medicine 627 buy phenytoin 100 mg low cost, and the perineal nerve and its branches. Extravasated urine may result from rupture of the bulbous portion of the spongy urethra below the urogenital diaphragm; the urine may pass into the superficial perineal space and spread inferiorly into the scrotum, anteriorly around the penis, and superiorly into the lower part of the abdominal wall. The urine cannot spread laterally into the thigh because the inferior fascia of the urogenital diaphragm (the perineal membrane) and the superficial fascia of the perineum are firmly attached to the ischiopubic rami and are connected with the deep fascia of the thigh (fascia lata). If the membranous part of the urethra is ruptured, urine escapes into the deep perineal space and can extravasate upward around the prostate and bladder or downward into the superficial perineal space. Lies between the urogenital diaphragm and the external genitalia, is perforated by the urethra, and is attached to the posterior margin of the urogenital diaphragm and the ischiopubic rami. Is thickened anteriorly to form the transverse ligament of the perineum, which spans the subpubic angle just behind the deep dorsal vein of the penis. Ischiocavernosus Muscles Arise from the inner surface of the ischial tuberosities and the ischiopubic rami. Maintain erection of the penis by compressing the crus and the deep dorsal vein of the penis, thereby retarding venous return. Arise from the perineal body and fibrous raphe of the bulb of the penis in the male and the perineal body in the female. Insert into the corpus spongiosum and perineal membrane in the male and the pubic arch and dorsum of the clitoris in the female. Compress the bulb in the male, impeding venous return from the penis and thereby maintaining erection. Contraction (along with contraction of the ischiocavernosus) constricts the corpus spongiosum, thereby expelling the last drops of urine or the final semen in ejaculation. Compress the erectile tissue of the vestibular bulbs in the female and constrict the vaginal orifice. Perineal Body (Central Tendon of the Perineum) Is a fibromuscular mass located in the center of the perineum between the anal canal and the vagina (or the bulb of the penis). Serves as a site of attachment for the superficial and deep transverse perineal, bulbospongiosus, levator ani, and external anal sphincter muscles. Deep Perineal Space (Pouch) Lies between the superior and inferior fasciae of the urogenital diaphragm. Contains the deep transverse perineal muscle and sphincter urethrae, the membranous part of the urethra, the bulbourethral glands (in the male), and branches of the internal pudendal vessels and pudendal nerve. Deep Transverse Perineal Muscle Arises from the inner surface of the ischial rami. Inserts into the medial tendinous raphe and the perineal body; in the female, it also inserts into the wall of the vagina. Has an inferior part that is attached to the anterolateral wall of the vagina in the female, forming a urethrovaginal sphincter that compresses both the urethra and vagina. Urogenital Diaphragm Consists of the deep transverse perineal muscle and the sphincter urethrae and is invested by superior and inferior fasciae. Stretches between the two pubic rami and ischial rami but does not reach the pubic symphysis anteriorly. Is pierced by the membranous urethra in the male and by the urethra and the vagina in the female. Lie among the fibers of the sphincter urethrae in the deep perineal pouch in the male, on the posterolateral sides of the membranous urethra. Ducts pass through the inferior fascia of the urogenital diaphragm to open into the bulbous portion of the spongy (penile) urethra. Ischiorectal (Ischioanal) Fossa (See Figures 6-1 and 6-2) Is the potential space on either side of the anorectum and is separated from the pelvis by the levator ani and its fasciae. Contains ischioanal fat, which allows distention of the anal canal during defecation; the inferior rectal nerves and vessels, which are branches of the internal pudendal vessels and the pudendal nerve; and perineal branches of the posterior femoral cutaneous nerve (which communicates with the inferior rectal nerve). This is a fascial canal formed by a split in the obturator internus fascia and transmits the pudendal nerve and internal pudendal vessels. Is occasionally the site of an abscess that can extend to other fossa by way of the communication over the anococcygeal raphe. Has a tendon that passes around the lesser sciatic notch to insert into the medial surface of the greater trochanter of the femur. Arises from the tip of the coccyx and the anococcygeal ligament, inserts into the central tendon of the perineum, is innervated by the inferior rectal nerve, and closes the anus. Is composed of three parts: subcutaneous, superficial (main part, attached to the coccyx and central tendon), and deep. Corrugator cutis ani muscle is a thin stratum of smooth muscle fibers radiating from the superficial part of the sphincter to the deep aspect of the perianal skin, causing puckering of that skin, which contributes to the air-/water-tight seal of the anal canal. Arises from the body of the pubis, the arcus tendineus of the levator ani (a thickened part of the obturator fascia), and the ischial spine. Is innervated by the branches of the anterior rami of sacral nerves S3 and S4 and the perineal branch of the pudendal nerve. Has as its most anterior fibers, which are also the most medial, the levator prostate or pubovaginalis. Fundiform Ligament of the Penis Arises from the linea alba and the membranous layer of the superficial fascia of the abdomen. Splits into left and right parts, encircles the body of the penis, and blends with the superficial penile fascia. Arises from the pubic symphysis and the arcuate pubic ligament and inserts into the deep fascia of the penis or into the body of the clitoris. Is continuous with the fascia covering the external oblique muscle and the rectus sheath. Tunica Albuginea Is a dense fibrous layer that envelops both the corpora cavernosa and the corpus spongiosum. Is more elastic around the corpus spongiosum, which, therefore, does not become excessively turgid during erection and permits passage of the ejaculate. Is a serous sac of the peritoneum that covers the front and sides of the testis and epididymis. Consists of a parietal layer that forms the innermost layer of the scrotum and a visceral layer adherent to the testis and epididymis. Is an embryonic diverticulum of the peritoneum that traverses the inguinal canal, accompanying the round ligament in the female or the testis in its descent into the scrotum and closes forming the tunica vaginalis in the male. If it does not close in females, it forms the canal of Nuck, which is an abnormal patent pouch of peritoneum extending into the labia majora. Persistence of the entire processus vaginalis develops a congenital indirect inguinal hernia, but if its middle portion persists, it develops a congenital hydrocele. Is a fibrous cord that connects the fetal testis to the floor of the developing scrotum, and its homologues in the female are the ovarian and round ligaments. Appears to play a role in testicular descent by pulling the testis down as it migrates. Scrotum Is a cutaneous pouch consisting of thin skin and the underlying dartos, which is continuous with the superficial penile fascia and superficial perineal fascia. The dartos muscle is responsible for wrinkling the scrotal skin, and the cremaster muscle is responsible for elevating the testis. Is covered with sparse hairs and has no fat, which is important in maintaining a temperature lower than the rest of the body for sperm production. Is contracted and wrinkled when cold (or sexually stimulated) to increase its thickness and reduce heat loss, bringing the testis into close contact with the body to conserve heat; is relaxed when warm and hence is flaccid and distended to dissipate heat. Receives blood from the external pudendal arteries and the posterior scrotal branches of the internal pudendal arteries. Is innervated by the anterior scrotal branch of the ilioinguinal nerve, the genital branch of the genitofemoral nerve, the posterior scrotal branch of the perineal branch of the pudendal nerve, and the perineal branch of the posterior femoral cutaneous nerve. Hematocele is a hemorrhage into the cavity of the tunica vaginalis due to injury to the spermatic vessels. Varicocele is an enlargement of the pampiniform venous plexus of the spermatic cord that appears like a "bag of worms" in the scrotum. A varicocele may cause dragging-like pain, atrophy of the testis and/or infertility. It is more common on the left side and can be treated surgically by removing the varicose veins. If a man wants to have children, it is recommended that he not wear tight underwear or tight jeans because tight clothing holds the testes close to the body wall, where higher temperatures inhibit sperm production. Under cold conditions, the testes are pulled up toward the warm body wall, and the scrotal skin wrinkles to increase its thickness and reduce heat loss. Penis (Figure 6-6) Consists of three masses of vascular erectile tissue; these are the paired corpora cavernosa and the midline corpus spongiosum, which are bounded by tunica albuginea. Consists of a root, which includes two crura and the bulb of the penis; and the body, which contains the single corpus spongiosum and the paired corpora cavernosa. Has a head called the glans penis, which is formed by the terminal part of the corpus spongiosum and is covered by a free fold of skin, the prepuce. The frenulum of the prepuce is a median ventral fold passing from the deep surface of the prepuce. The prominent margin of the glans penis is the corona, the median slit near the tip of the glans is the external urethral orifice, and the terminal dilated part of the urethra in the glans is the fossa navicularis. Preputial glands are small sebaceous glands of the corona, the neck of the glans penis, and the inner surface of the prepuce, which secrete an odoriferous substance, called smegma. Epispadias is a congenital malformation in which the spongy urethra opens as a groove on the dorsum of the penis, frequently associated with the bladder exstrophy (congenital eversion or turning inside out of an organ, as the bladder). Hypospadias is a congenital malformation in which the urethra opens on the underside of the penis because of a failure of the two urethral folds to fuse completely. It is frequently associated with chordee, which is a ventral curvature of the penis. Circumcision is the removal of the foreskin (prepuce) that covers the glans of the penis. It is performed as a therapeutic medical procedure for pathologic phimosis, chronic inflammations of the penis, and penile cancer. Phimosis is a condition in which the foreskin (prepuce) cannot be fully retracted to reveal the glans due to a narrow opening of the prepuce. A very tight foreskin around the tip of the penis may interfere with urination or sexual function. Paraphimosis is a painful constriction of the glans penis caused by a tight band of constricted and retracted phimotic foreskin behind the corona. This ring of tissue causes penile ischemia and vascular engorgement, swelling, and edema, leading to penile gangrene. Labia Majora Are two longitudinal folds of skin that run downward and backward from the mons pubis and are joined anteriorly by the anterior labial commissure. Their outer surfaces are covered with pigmented skin, and after puberty, the labia majora are covered with hair. Are divided into upper (lateral) parts, which, above the clitoris, fuse to form the prepuce of the clitoris, and lower (medial) parts, which fuse below the clitoris to form the frenulum of the clitoris. Has the openings for the urethra, the vagina, and the ducts of the greater vestibular glands in its floor. Is homologous to the penis in the male, consists of erectile tissue, is enlarged as a result of engorgement with blood, and is not perforated by the urethra. Consists of two crura, two corpora cavernosa, and a glans but no corpus spongiosum. Are the homologues of the bulb of the penis of the corpus spongiosum, a paired mass of erectile tissue on each side of the vaginal orifice. Are covered by the bulbospongiosus muscle, and each bulb is joined to one another and to the undersurface of the glans clitoris by a narrow band of erectile tissue. Crosses the ischial spine and enters the perineum with the internal pudendal artery through the lesser sciatic foramen. Enters the pudendal canal, gives rise to the inferior rectal nerve and the perineal nerve, and terminates as the dorsal nerve of the penis (or clitoris). Pudendal nerve block is performed by injecting a local anesthetic near the pudendal nerve. It is accomplished by inserting a needle through the posterolateral vaginal wall, just beneath the pelvic diaphragm and toward the ischial spine, thus placing the needle around the pudendal nerve. Communicates in the ischiorectal fossa with perineal branch of the posterior femoral cutaneous nerve, which supplies the scrotum or labium majus. Arises within the pudendal canal and divides into a deep branch, which supplies all of the perineal muscles, and a superficial (posterior scrotal or labial) branch, which supplies the scrotum or labia majora. Pierces the perineal membrane, runs between the two layers of the suspensory ligament of the penis or clitoris, and runs deep to the deep fascia on the dorsum of the penis or clitoris to innervate the skin, prepuce, and glans. Leaves the pelvis by way of the greater sciatic foramen between the piriformis and coccygeus and immediately enters the perineum through the lesser sciatic foramen by hooking around the ischial spine. Inferior Rectal Artery Arises within the pudendal canal, pierces the wall of the pudendal canal, and breaks into several branches, which cross the ischiorectal fossa to muscles and skin around the anal canal. Supply the superficial perineal muscles and give rise to transverse perineal branches and posterior scrotal (or labial) branches. Arises within the deep perineal space, pierces the perineal membrane, and supplies the bulb of the penis and the bulbourethral glands (in the male) and the vestibular bulbs and the greater vestibular gland (in the female). Urethral Artery Pierces the perineal membrane, enters the corpus spongiosum of the penis, and continues to the glans penis. Pierce the perineal membrane, run through the center of the corpus cavernosum of the penis or clitoris, and supply its erectile tissue. Pierce the perineal membrane and pass through the suspensory ligament of the penis or clitoris.
Syndromes
The astrocyte: Astrocytes have an enormous amount of processes that wrap around blood vessels and neurons treatment coordinator order 100mg phenytoin otc. Because of this arrangement symptoms multiple myeloma purchase phenytoin 100 mg with amex, astrocytes are ideally positioned to medicine to stop vomiting buy 100mg phenytoin overnight delivery control and modify the extracellular environment around neurons medicine of the people proven phenytoin 100mg. Most of the functions of the astrocyte are attributed to medicine list cheap phenytoin 100 mg with amex controlling this environment medications kidney failure purchase 100mg phenytoin amex. The main source is blood glucose, but glycogen levels can sustain the need for 5 to 10 min. K+ permeability Active neurons lose K+ into the extracellular spaces, which would act as a positive feedback system for depolarization if the K+ was not trapped by the astrocytes. Gap Junctions Astrocytes are coupled to each other, as well as other glial cells and neurons through gap junctions. Neurotransmitters Astrocytes synthesize over 20 different neurotransmitters and take up excess neurotransmitters to help terminate signals at the synapse. Growth factors Astrocytes secrete a variety of growth factors, which are important for the establishment of fully functioning excitatory synapses. Function 154 Blood flow Astrocytes can modulate blood flow in the brain by inducing localized vasodilation or vasoconstriction. This modulation can occur through gap junctions between the astrocytes and the endothelial cells of brain blood vessels. Astrocyte processes associated with capillaries and neurons 155 the Oligodendroctye: the primary function of the oligodendorcyte is to provide and maintain the myelin sheaths around axons. It allows for electrical signals to be propagated along one axon without being spread to other axons. Oligodendrocytes send out long 15 to 30 processes, which wrap many times around a section of an axon. Between each "wrapping," there is a small area of exposed axon called the node of Ranvier. The wrapping creates many layers of tightly compressed membranes that is called myelin. Myelination speeds up the conduction of the action potential down the axon by allowing the action potentials to occur only at the nodes, a process called saltatory conduction. Myelination also induces the clustering of voltage-gated Na+ channels at the nodes. The reduction in myelin severely decreases the conduction velocity and duration of action potentials in the affected neuron. These cells are also very important in presenting antigens to lymphocytes in response to infection. For this reason, medical intervention in response to brain injury often involves factors that inhibit microglial activity. Maintenance of posture: Without much conscious control, our muscles generate a constant contractile force that allows us to maintain an erect or seated position, or posture. Respiration: Our muscular system automatically drives movement of air into and out of our body. Heat generation: Contraction of muscle tissue generates heat, which is essential for maintenance of temperature homeostasis. For instance, if our core body temperature falls, we shiver to generate more heat. Communication: Muscle tissue allows us to talk, gesture, write, and convey our emotional state by doing such things as smiling or frowning. Constriction of organs and blood vessels: Nutrients move through our digestive tract, urine is passed out of the body, and secretions are propelled out of glands by contraction of smooth muscle. Constriction or relaxation of blood vessels regulates blood pressure and blood distribution throughout the body. Pumping blood: Blood moves through the blood vessels because our heart tirelessly receives blood and delivers it to all body tissues and organs. Among the many possible examples are the facts that muscles help protect fragile internal organs by enclosing them, and are also critical in maintaining the integrity of body cavities. For example, fetuses with incompletely formed diaphragms have abdominal contents herniate (protrude) up into the thoracic cavity, which inhibits normal lung growth and development. Even though this is an incomplete list, an appreciation of some of these basic muscle functions will help you as we proceed. For instance, in order to flex (decrease the angle of a joint) your elbow you need to contract (shorten) the biceps brachii and other elbow flexor muscles in the anterior arm. Notice that in order to extend your elbow, the posterior arm extensor muscles need to contract. Excitability is the ability to respond to a stimulus, which may be delivered from a motor neuron or a hormone. In order to be able to flex the elbow, the elbow extensor muscles must extend in order to allow flexion to occur. Skeletal Muscle Skeletal muscle is also known as voluntary muscle because we can consciously, or voluntarily, control it in response to input by nerve cells. Skeletal muscle, along with cardiac muscle, is also referred to as striated ("striped") because it has a microscopically streaked or striped appearance. Skeletal muscle and its associated connective tissue comprise about 40% of our weight. You may want to write the following words onto your pillowcase: skeletal, striated, and voluntary. More likely, however, is that your landlord will make you replace your pillowcase. Cardiac and most smooth muscles are autorhythmic-they are capable of contracting spontaneously without nervous or hormonal stimulation. The heart contracts or beats about 100,000 times per day, 36 million times per year, and about 2. You may want to write these words on the other side of your pillowcase: cardiac, striated, and involuntary. Smooth Muscle Smooth muscle is widely distributed throughout the body, being found in the walls of hollow organs such as our digestive, reproductive, and urinary tracts, tubes such as blood vessels and airways, and in other locations, such as the inside of the eye. It gets its name because it lacks the striped appearance that skeletal and cardiac muscle display microscopically. Along with cardiac muscle, smooth muscle is involuntary-not under our conscious control. Smooth muscle is sometimes known as visceral muscle because it is a major component of many internal (visceral) organs. Step 03 With your newly labeled image in hand, read through the following paragraphs. For those who cannot participate in the steps above a Skeletal Muscle Organization Alternative Assignment has been provided, giving you all of the information found in the interactive tutorial. Skeletal Muscle Cells-Gross and Microscopic Structure Each skeletal muscle cell, also called a muscle fiber, develops as many embryonic myocytes fused into one long, multi-nucleated skeletal muscle cell. These muscle fibers are bound together into bundles, or fascicles, and are supplied with a rich network of blood vessels and nerves. In an intact skeletal muscle, a rich network of nerves and blood vessels nourish and control each muscle cell. These muscle fibers are individually wrapped and then bound together by several different layers of fibrous connective tissue. The epimysium ("epi"-outside, and "mysium"-muscle) is a layer of dense fibrous connective tissue that surrounds the entire muscle. Each skeletal muscle is formed from several bundled fascicles of skeletal muscle fibers, and each fascicle is surrounded by perimysium ("peri"around). Each single muscle cell is wrapped individually with a fine layer of loose (areolar) connective tissue called endomysium ("endo"-inside). These connective tissue layers are continuous with each other and they all extend beyond the ends of 162 the muscle fibers themselves, forming the tendons that anchor muscles to bone, moving the bones when the muscles contract. Deep to the endomysium, each skeletal muscle cell is surrounded by a cell membrane known as the sarcolemma (You will see the prefixes sarc- and myoquite a bit in this discussion, so you should understand that these are prefixes that refer to "muscle"). The cytoplasm, or sarcoplasm contains a large amount of glycogen (the storage form of glucose) for energy, and myoglobin-a red pigment similar to hemoglobin that can store oxygen. Most of the intracellular space, however, is taken up by rod-like myofibrils-cylindrical protein structures. Each muscle fiber contains hundreds or even thousands of myofibrils that extend from one end of each muscle fiber to the other. These myofibrils take up about 80% of the intracellular space, and are so densely packed inside these cells that mitochondria and other organelles get sandwiched between them while the nuclei get pushed to the outside and are located on the periphery right under the sarcolemma. Each myofibril is comprised of several varieties of protein molecules that form the myofilaments, and each myofilament contains the contractile segments that allow contraction. These contractile segments are known as sarcomeres ("sarc-" muscle, "mere" - part). The striations seen microscopically within skeletal muscle fibers are formed by the regular, organized arrangement of myofilaments-much like what we would see if we painted stripes on chopsticks and bundled them together with plastic wrap, with the plastic representing the sarcolemma. The striations microscopically visible in skeletal muscle are formed by the regular arrangement of proteins inside the cells. The dark areas are called A bands, which is fairly easy to remember because "a" is the second letter in "dark. Also, in the middle of each A band is a lighter H zone (H for "helle"-"bright"), and each H zone has a darker M line (M for "middle") running right down the middle of the A band. Each myofibril, in turn, contains several varieties of protein molecules, called myofilaments. The larger, or thick myofilaments are made of the protein, myosin, and the smaller thin myofilaments are chiefly made of the protein, actin. Each actin molecule is composed of two strands of fibrous actin (F actin) and a series of troponin and tropomyosin molecules. Each F actin is formed by two strings of globular actin (G actin) wound together in a double helical structure, much like twisting two strands of pearls with each other. Each G actin molecule would be represented by a pearl on our 165 hypothetical necklace. Each G actin subunit has a binding site for the myosin head to attach to the actin. Tropomyosin is a long string-like polypeptide that parallels each F actin strand and functions to either hide or expose the "active sites" on each globular actin molecule. Each tropomyosin molecule is long enough to cover the active binding sites on seven G-actin molecules. Associated with each tropomyosin molecule is a third polypeptide complex known as troponin. Troponin complexes contain three globular polypeptides (Troponin I, Troponin T, and Troponin C) that have distinct functions. Troponin I binds to actin, Troponin T binds to tropomyosin and helps position it on the F actin strands, and Troponin C binds calcium ions. When calcium binds to Troponin C, it causes a conformational change in the entire complex that results in exposure of the myosin binding sites on the G actin subunits. The thick myofilaments are composed chiefly of the protein myosin, and each thick myofilament is composed of about 300 myosin molecules bound together. The heavy chains have a shape similar to a golf club, having a long shaft-like structure, to which is connected the globular myosin head. The shafts, or tails wrap around each other and interact with the tails of other myosin molecules, forming the shaft of the thick filament. Half of the myosin molecules have their heads oriented toward one end of the thick filament, and the other half are oriented in the opposite direction. The connection between the head and the shaft of the myosin molecules functions as a hinge, and as such is referred to as the hinge region. The hinge region can bend, and as we shall see later, creates the power stroke when the muscle contracts. The center of the thick filaments are composed only of the shaft portions of the heavy chains. Each of the myosin heads is associated with two myosin light chains that play a role in regulating the actions of the myosin heads, but the exact mechanism is not fully understood. Imagine that you were looking at a thick filament from the end, and that there is a myosin head sticking straight up. As you moved around the circumference of the thick filament, you would see myosin heads every 30 degrees. This arrangement requires that 166 there be two thin filaments for every thick filament in the myofibril (see image below). To summarize, in order for the shortening of the muscle to occur, the myosin heads have three important properties: 1. The heads are attached to the rod-like portions of the heavy myosin molecules by a hinge region as already discussed, and 3. The Z-line (or Z-disc) is composed of proteins (alpha actinin) which provide an attachment site for the thin filaments. Likewise, the M-line is composed of proteins (myomesin) that hold myosin molecules in place. The A band is formed by myosin molecules, and the I band is the location where thin filaments do not overlap the thick filaments. The H zone is that portion of the A band where the thick and thin filaments do not overlap. There is another important structural protein that extends from the Z disc to the M line, running within the thick filament. Due to its large size, this protein is called titin (titin is the largest known protein in the human body and has roughly 30,000 amino acids). It forms the core of the thick myofilaments, holding it in place, and thus keeping the A band organized. In addition, titin has the ability to stretch and recoil and functions to prevent overstretching and damage to the muscle as well as to return it to its normal length when the muscle is stretched beyond its normal resting length. Recall that one of the properties of muscle is its elasticity, titin is the protein responsible for this property.
In order to medications every 8 hours purchase phenytoin 100 mg amex delineate this point medications used to treat migraines buy 100mg phenytoin with visa, we have used the model of studies on human aging in which the majority of studies reported impaired cognitive function in older adults when compared to treatment ulcer generic phenytoin 100 mg young acute treatment discount phenytoin 100 mg without prescription. We have argued that some of these effects might be due to treatment 911 purchase 100mg phenytoin overnight delivery the stress that is generated by the testing conditions that we use to symptoms jaw bone cancer purchase 100mg phenytoin with mastercard study young and older adults. Clearly, the field of psychoneuroendocrinology, which studies the effects of hormones on human brain and behavior, contributed significantly at showing the impact of stress on human cognitive function. It is our hope that by combining our expertise with that of the field of cognitive neuropsychology, we will be able to delineate with high accuracy the processes of cognitive function in humans that are not tainted by stress effects. We also hope that the combination of our fields will help in the understanding of the effects that stress can have on learning and memory in humans of all ages. Cortisol variation in humans affects memory for emotionally laden and neutral information. Endogenous cortisol elevations are related to memory facilitation only in individuals who are emotionally aroused. On the constitutional and local effects of disease of the suprarenal capsules (67th ed. Serum corticosterone level predicts the magnitude of hippocampal primed burst potentiation and depression in urethane-anesthetized rats. Cortisol effects on attentional processes in man as indicated by event-related potentials. 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A 59-year-old man is diagnosed with prostate cancer following a digital rectal examination symptoms when quitting smoking order phenytoin 100 mg on line. An obstetrician performs a median episiotomy on a woman before parturition to medications 3601 buy phenytoin 100mg free shipping prevent uncontrolled tearing symptoms of kidney stones buy 100 mg phenytoin free shipping. If the perineal Chapter 6 body is damaged sewage treatment discount phenytoin 100 mg overnight delivery, the function of which of the following muscles might be impaired A 62-year-old man is incapable of penile erection after rectal surgery with prostatectomy medicine x pop up discount phenytoin 100 mg visa. A 22-year-old man has a gonorrheal infection that has infiltrated the space between the inferior fascia of the urogenital diaphragm and the superficial perineal fascia counterfeit medications 60 minutes buy phenytoin 100mg amex. A 39-year-old man is unable to expel the last drops of urine from the urethra at the end of micturition because of paralysis of the external urethral sphincter and bulbospongiosus muscles. This condition may occur as a result of injury to which of the following nervous structures A sexually active adolescent presents with an infection within the ischiorectal fossa. A first-year resident in the urology department reviews pelvic anatomy before seeing patients. A 21-year-old marine biologist asks about her first bimanual examination, and it is explained to her that the normal position of the uterus is: (A) the dorsal artery of the penis supplies the glans penis. After his bath but before getting dressed, a 4-year-old boy was playing with his puppy. Repair of a prolapsed uterus requires knowledge of the supporting structures of the uterus. Which of the following structures plays the most important role in the support of the uterus A 16-year-old boy presents to the emergency department with rupture of the penile urethra. Extravasated urine from this injury can spread into which of the following structures While performing a pelvic exenteration, the surgical oncologist notices a fractured or ruptured boundary of the pelvic inlet. A 32-year-old patient with multiple fractures of the pelvis has no cutaneous sensation in the urogenital triangle. A 53-year-old bank teller is admitted to a local hospital for surgical removal of a benign pelvic tumor confined within the broad ligament. There is a risk of injuring which of the following structures that lies in this ligament A 22-year-old victim of an automobile accident has received destructive damage to structures that form the boundary of the perineum. Which of the following structures is most readily palpated during rectal examination A physician performing the vasectomy by making an incision on each side of the scrotum should remember which of the following statements most applicable to the scrotum A 48-year-old college football coach undergoes a radical prostatectomy for a malignant tumor in his prostate. A 37-year-old woman complains of a bearing-down sensation in her womb and an increased frequency of and burning sensation on urination. Which of the following structures provides the primary support for the cervix of the uterus A radiologist interprets a lymphangiogram for a 29-year-old patient with metastatic carcinoma. Upper lumbar nodes most likely receive lymph from which of the following structures Which of the following structures is most likely compressed by this mass when crossing the pelvic brim During pelvic surgery, a surgeon notices severe bleeding from the artery that remains within the true pelvis. A 26-year-old man comes to a hospital with fever, nausea, pain, and itching in the perineal region. A neurosurgeon performs surgical resection of a rare meningeal tumor in the sacral region. He tries to avoid an injury of the nerve that arises from the lumbosacral plexus and remains within the abdominal or pelvic cavity. After repair of a ruptured diverticulum, a 31-year-old patient begins to spike with fever and complains of abdominal pain. An infection in the deep perineal space would most likely damage which of the following structures During physical examination, the pediatrician palpated the testis in the inguinal canal. She describes characteristics of structures above the pectinate line of the anal canal, which include: 47. An obstetrician is about to perform a pudendal block so a woman can experience less pain when she delivers her child. A trauma surgeon in the emergency department at a local center examines a 14-year-old boy with extensive pelvic injuries after a hit and run accident. The surgeon inspects the ischiorectal fossa because it: (A) (B) (C) (D) (E) Labioscrotal swellings or folds Urogenital sinus Spongy urethra Phallus Urethral folds 52. The cancer is likely to metastasize via the veins into which of the following structures The seminal colliculus of his prostate gland is infected, and its fine Questions 53 to 57: Choose the appropriate lettered structure in this computed tomography scan (see figure below) of the female perineum and pelvis. Which structure extends between the vestibule and the cervix of the uterus and serves as the excretory channel for the products of menstruation Which structure, when fractured, results in paralysis of the obturator internus muscles Which structure secretes fluid containing fructose, which allows for forensic determination of rape Which structure in the female is much shorter than the corresponding structure in the male In which structure would ligation of the external iliac artery reduce blood pressure Into which structure does hemorrhage occur after injury to the inferior rectal vessels A stab wound immediately superior to the pubic symphysis on the anterior pelvic wall would most likely injure which visceral organ first Which structure is innervated by the nerve passing through both the greater and lesser sciatic foramina Questions 58 to 62: Choose the appropriate lettered structure in this computed tomography scan (see figure below) of the male perineum and pelvis. The round ligament of the uterus runs laterally from the uterus through the deep inguinal ring, inguinal canal, and superficial inguinal ring and becomes lost in the subcutaneous tissues of the labium majus. Thus, carcinoma of the uterus can spread directly to the labium majus by traveling in lymphatics that follow the ligament. A tender swollen left testis may be produced by thrombosis in the left renal vein because the left testicular vein drains into the left renal vein. The left inferior epigastric vein drains into the left external iliac vein, and the left external pudendal vein empties into the femoral vein. The superior gluteal nerve leaves the pelvis through the greater sciatic foramen, above the piriformis. The sciatic nerve, internal pudendal vessels, inferior gluteal vessels and nerve, and posterior femoral cutaneous nerve leave the pelvis below the piriformis. The pelvic splanchnic nerves carry preganglionic parasympathetic general visceral efferent fibers that synapse in the ganglia of the inferior hypogastric plexus and in terminal ganglia in the muscular walls of the pelvic organs. The sympathetic preganglionic fibers synapse in the sympathetic chain (paravertebral) ganglia or in the collateral (prevertebral) ganglia. The two sympathetic trunks unite and terminate in the ganglion impar (coccygeal ganglion), which is the most inferior, unpaired ganglion located in front of the coccyx. The ureter runs under the uterine artery near the cervix; thus, the ureter is sometimes mistakenly ligated during pelvic surgery. The other structures mentioned are not closely related to the uterine artery near the uterine cervix. The pelvic diaphragm is formed by the levator ani and coccygeus, whereas the urogenital diaphragm consists of the sphincter urethrae and deep transverse perinei muscles. The piriformis passes through the greater sciatic notch and inserts on the greater trochanter of the femur. The sphincter ani externus is composed of three layers, including the subcutaneous (corrugator cutis ani), superficial, and deep portions, and maintains a voluntary tonic contracture. The glans clitoris is derived from the corpora cavernosa, whereas the glans penis is the expanded terminal part of the corpus spongiosum. Erection of the penis is caused by parasympathetic stimulation, whereas ejaculation is mediated via the sympathetic nerve. The ovaries are not enclosed in the broad ligament, but their anterior surface is attached to the posterior surface of the broad ligament. The superior (deep) boundary of the superficial perineal space is the perineal membrane (inferior fascia of the urogenital diaphragm). The deep perineal fascia essentially divides the superficial perineal space into a superficial and deep compartment. The crus of the penis, bulb of the vestibule, spongy urethra, and great vestibular gland are found in the superficial perineal space. The middle lobe of the prostate gland is commonly involved in benign prostatic hypertrophy, resulting in obstruction of the prostatic urethra, whereas the posterior lobe is commonly involved in carcinomatous transformation. The anterior lobe contains little glandular tissue, and the two lateral lobes on either side of the urethra form the major part of the gland. Ducts from the prostate gland open into the prostatic sinus, which is a groove on either side of the urethral crest. The prostate gland receives the ejaculatory duct, which opens into the prostatic urethra on the seminal colliculus (a prominent elevation of the urethral crest) just lateral to the prostatic utricle, which is a small blind pouch. The bulbourethral gland lies on the lateral side of the membranous urethra within the deep perineal space, but its duct opens into the bulbous portion of the spongy (penile) urethra. A needle should be inserted through the posterior fornix just below the posterior lip of the cervix while the patient is in the supine position to aspirate abnormal fluid in the cul-de-sac of Douglas (rectouterine pouch). Rectouterine excavation is not most efficiently aspirated by puncture of other structures. The superficial inguinal nodes receive lymph from the penis, scrotum, buttocks, labium majus, and the lower parts of the vagina and anal canal. These nodes have efferent vessels that drain primarily into the external iliac and common iliac nodes and ultimately to the lumbar (aortic) nodes. The internal iliac nodes receive lymph from the upper part of the rectum, vagina, uterus, and other pelvic organs, and they drain into the common iliac nodes and then into the lumbar (aortic) nodes. Lymph vessels from the glans penis drain initially into the deep inguinal nodes and then into the external iliac nodes. The urogenital diaphragm consists of the sphincter urethrae and deep transverse perineal muscles. Weakness of the muscles, ligaments, and fasciae of the pelvic floor, such as the pelvic diaphragm, urogenital diaphragm, and cardinal (transverse cervical) ligaments, occurs as result of multiple child delivery, advancing age, and menopause. The superficial transversus perinei is one of the superficial perineal muscles, and the obturator internus forms the lateral wall of the ischiorectal fossa. The deep dorsal vein, dorsal artery, and dorsal nerve of the penis pass through a gap between the arcuate pubic ligament and the transverse perineal ligament. The perineal nerve divides into a deep branch, which supplies all of the perineal muscles, and superficial branches as posterior scrotal nerves that supply the scrotum. The perineal body (central tendon of the perineum) is a fibromuscular node at the center of the perineum. It provides attachment for the bulbospongiosus, the superficial and deep transverse perineal muscles, and the sphincter ani externus muscles. Other muscles (ischiocavernosus, sphincter urethrae, and obturator internus) are not attached to the perineal body. The perineal branch of the pudendal nerve supplies the external urethral sphincter and bulbospongiosus muscles in the male. All other nervous structures do not supply skeletal muscles but supply smooth muscles in the perineal and pelvic organs. The pelvic and prostatic plexuses contain both sympathetic and parasympathetic nerve fibers. The pelvic splanchnic nerve contains preganglionic parasympathetic fibers, whereas the sacral splanchnic nerve contains preganglionic sympathetic fibers. Parasympathetic fibers are responsible for erection, whereas sympathetic fibers are involved with ejaculation. The right and left hypogastric nerves contain primarily sympathetic fibers and visceral sensory fibers. The dorsal nerve of the penis and the perineal nerve provide sensory nerve fibers. The lymphatic vessels from the ovary ascend with the ovarian vessels in the suspensory ligament and terminate in the lumbar (aortic) nodes. Lymphatic vessels from the perineum, external genitalia, and lower part of the anterior abdominal wall drain into the superficial inguinal nodes. The ischiorectal fossa contains the inferior rectal nerves and vessels and adipose tissue. The bulb of the vestibule and the great vestibular gland are located in the superficial perineal space, whereas the bulbourethral gland is found in the deep perineal space. The internal pudendal artery runs in the pudendal canal, but its branches pass through the superficial and deep perineal spaces.
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