Biomedical subjects

Ahmed Shafik

Publications and source records attributed to Ahmed Shafik.

At least 19 recordsLinked to original sources

PubMed2006

Mechanism of gastric emptying through the pyloric sphincter: a human study.

BACKGROUND: The current view holds that gastric emptying is effected by the force of the antral peristaltic wave squeezing food particles through pyloric sphincter resistance. Whether this is accomplished by a reflex action was investigated. MATERIAL/METHODS: The study comprised 12 healthy volunteers (age: 42.2+/-10.6 years). A balloon-tipped and a manometric tube were introduced into the stomach. Pressure responses in the proximal stomach, pyloric antrum, and pyloric sphincter to distension of the proximal stomach and of the antrum were recorded. Pyloric sphincter distension was induced to test its effect on antral and proximal stomach pressure. These tests were repeated in nine men after separately anesthetizing the pyloric antrum and sphincter. RESULTS: Distension of the proximal stomach produced no pressure changes in the proximal stomach, pyloric antrum, or sphincter (p>0.05). Antral distension effected a significant rise in antral pressure, but not in the proximal stomach. Significant sphincter pressure decrease occurred only with antral distension volumes >50 ml. Pyloric sphincter distension produced a significant rise in antral pressure, but not in the proximal stomach. Sphincteric or antral anesthetization produced no pressure changes in the pyloric sphincter, antrum, or proximal stomach. CONCLUSIONS: Pyloric sphincter relaxation upon antral distension implies a reflex relationship the authors call the "antro-sphincteric inhibitory reflex". Pyloric sphincter distension effected antral contraction, which is suggested to be a reflex in nature and which they term the "sphinctero-antral excitatory reflex". It is postulated that these two reflexes act to churn and transport gastric contents to the duodenum.

Adult↗

PubMed2006

Physioanatomical relationship of the external anal sphincter to the bulbocavernosus muscle in the female.

Both external anal sphincter (EAS) and bulbocavernosus muscle (BCM) have been shown anatomically and physiologically to constitute one muscle in males. We investigated the hypothesis that the EAS and BCM have similar anatomical pattern in females. The study consisted of cadaveric dissection, electromyographic recordings and inferior rectal nerve stimulation. Bulbocavernosus reflex action was performed in 16 healthy women before and after anesthetization of the EAS and BCM. The EAS extended forward across the perineal body and became continuous with the BCM in the labia majora. Glans clitoris (GC) or inferior rectal nerve stimulation effected synchronous EAS and BCM contractions with identical action potentials. GC stimulation while the EAS or BCM was anesthetized produced neither EAS nor BCM response. Similarly, stimulation of the anesthetized GC produced no EAS or BCM response. The BCM and EAS apparently constitute a single muscle, which seems to play dual and yet synchronous roles in fecal control and sexual response.

Adult↗

PubMed2006

Study of the cremasteric muscle during erection.

BACKGROUND: Mechanism of testicular elevation during erection is not known. We investigated the hypothesis that erection evokes reflex cremasteric muscle (CM) contraction which effects testicular elevation. METHODS: Electromyographic (EMG) response of CM to erection was recorded in 26 healthy volunteers (age 36.7 +/- 6.8 SD years). Erection was induced by intracavernosal injection of alprostadil. CM response was tested before and after individual glans penis (GP) and CM anesthetization. RESULTS: The CM exhibited resting electric activity of mean amplitude of 74.8 +/- 6.3 microV which, on erection, increased to 486.6 +/- 36.8 microV (P < 0.001). Response was momentary. Anesthetization of erect GP did not effect increase of CM EMG activity, while bland gel did. Anesthetized CM did not respond to GC erection while saline infiltrated did. CONCLUSIONS: The CM appears to contract during erection through a reflex which we call 'peno-cremasteric reflex'. CM contraction assumingly elevates testicle and support cord veins; it may effect testicular compression, thus expressing its secretions into vas deferens.

Action Potentials↗

PubMed2006

Effect of straining on the muscles of the anterior abdominal wall. Identification of the 'straining-abdominal wall reflex'.

The external and internal oblique, transverse abdominis and the rectus abdominis muscles constitute the anterolateral abdominal wall muscles. They are striated and contract voluntarily. We investigated the hypothesis that contraction of these muscles by coughing or straining, can also occur as a reflex. Effect of straining on muscles was tested in 19 healthy volunteers. The intra-abdominal pressure was measured by a manometric catheter introduced into the rectum. The response of the muscles to straining was recorded by a needle electrode inserted into each of the muscles. Similar to voluntary contractions, sudden and sustained straining produced increase in the rectal pressure and the motor unit action potentials of each of the muscles which was abolished by anesthesia. These findings suggest presence of a 'straining-abdominal wall reflex'.

Abdominal Wall↗

PubMed2006

Corpora cavernosa as an alternative route for transfusion.

Routine intravenous blood transfusion is difficult when the blood pressure falls significantly or veins are inaccessible or are sclerotic due to multiple transfusions. Here, we describe the use of penile corpora cavernosa (CC), as an alternative route for blood transfusion and fluid replacement. The study was conducted in 15 men, 7 with massive burns, 6 with sclerotic veins from repeated injections, and 2 with extensive limb trauma. After the conventional methods of blood and fluid infusions were exhausted, a needle was inserted into CC for blood and fluid administration. During blood or saline infusions, penile shaft became elongated but returned to a normal length after termination of the infusion. There were no difficulties during needle insertion into CC, in varying the different transfusion rates, or in repetition of transfusion during the same or the subsequent days. Complications were rare with the exception of a subcutaneous penile hematoma in 2 patients which disappeared spontaneously. Erection was not disturbed in five patients who were followed for a mean of 10.4+/-1.8 months. These findings show that corpora cavernosa can be used for blood transfusion or for administration of fluids as a simple, easy, rapid, and safe vascular access in conditions in which conventional routes are inaccessible.

Adult↗

PubMed2006

Demonstration of a physiologic sphincter at duodeno-jejunal junction.

Current evidence suggests that there are three sphincters that regulate the flow of chyme from stomach to the duodenum. We investigated the hypothesis whether a fourth 'physiologic sphincter' exists at the duodeno-jejunal junction. The pressure response of the jejunum, duodeno-jejunal junction and duodenum to individual balloon distension of the jejunum and duodenum was recorded in 28 healthy subjected before and after anesthesizing the jejunum, duodeno-jejunal junction and duodenum. The duodeno-jejunal junction length was measured by the station pull-through technique. Duodenal balloon distension with 2 and 4 ml of normal saline did not change the pressures in the duodenum, duodeno-jejunal junction or jejunum (p > 0.05). Distension with 6 ml saline produced an increase of duodenum pressure (p < 0.01), a decrease of duodeno-jejunal junction pressure (p < 0.01), and no change in the pressure of the jejunum (p > 0.05), the balloon was expelled to the jejunum. Eight, and 10 ml duodenum balloon distension produced pressure changes similar to those of the 6 ml distension (p > 0.05). Jejunum balloon distension with 2 and 4 ml saline induced no jejunum, duodeno-jejunal junction or duodenum pressure changes (p > 0.05). Six ml balloon distension effected increase of jejunum (p < 0.01) and duodeno-jejunal junction (p < 0.05) pressure, but no duodenum pressure changes (p > 0.05). Jejunum balloon distension with volumes more than 6 ml produced pressure changes similar to the 6 ml distension. Distension of the anesthetized duodenum, duodeno-jejunal junction or jejunum did not change the duodeno-jejunal junction pressure. A high pressure zone of 1.6+/-0.04 cm length was detected at the duodeno-jejunal junction. Together, the findings show that a high pressure zone exists at the duodeno-jejunal junction suggesting that this region might act as a physiological sphincter.

Adult↗

PubMed2006

Detection of predefecatory rectosigmoid wave activity for prevention of fecal soiling in infants.

Identification of an electrophysiologic sign before defecation can prevent fecal soiling in infants. To identify such a sign, the contractile activity of sigmoid colon was recorded percutaneously in 48 healthy infants. The recorder was equipped with a digital clock synchronized to the recorder so as to set off an alarm upon significantly increased electromyographic activity of sigmoid colon. Examination of the recordings at high speed revealed three types of basal, signaling and predefecatory waves of activities. The 'basal' component was comprised of as negatively deflected slow waves. The signaling waves exhibited an increase in amplitudes, cycle rate and conduction velocity, were repeated 8.2+/-1.2 times and lasted for 14.6+/-2.1 minutes prior to defecation, The 'predefecatory' waves preceded defecation by 40.3+/-7.3 seconds, showed a significant increase in wave parameters and sounded the alarm. The findings show a method for early detection of defecation that can be used clinically to prevent fecal soiling in infants.

Colon, Sigmoid↗

PubMed2006

Flaturia: passage of flatus at coitus. Incidence and pathogenesis.

BACKGROUND/AIM: We present 18 women who under normal conditions had fecal and flatus control. They leaked flatus only during coitus. We investigated the hypothesis that these women had a concealed anal sphincteric disorder. METHODS: Eighteen multiparous women (mean age 44.8+/-7.2 SD years) complained of involuntary passage of flatus during coitus of 4.6+/-2.4 years duration. Mean deliveries amounted to 8.2+/-2.1, of which 5.2+/-1.1 were by forceps. Patients had neither fecal nor flatus incontinence except during coitus. Nine healthy volunteers matching patients in age and number of deliveries but without coital passage of flatus were included in the study. Monitoring comprised anorectal pressure studies and external and internal anal sphincter (EAS, IAS) electromyography (EMG). Plain X-ray and barium enema studies were done to detect stools in the rectum. RESULTS: The rectal and anal pressures at rest and on voluntary squeeze of the patients matched those of the healthy volunteers. The recto-anal inhibitory reflex (RAIR) in the patients was abnormal; it recorded on rectal contraction a significantly lower anal pressure than that of the healthy volunteers; also, the rectal contraction occurred at a volume lower than with the volunteers. The EAS EMG of patients was normal, while their IAS EMG recorded a significantly lower activity at rest and on rectal distension than those of volunteers. Stools were detected at rest in the rectum of all patients and in only two of the volunteers. CONCLUSIONS: The distal end of the erect penis seems to buffet the lower rectum at coitus. In patients, the abnormal RAIR, the diminished IAS EMG as well as the presence of stools in the rectum at rest appear to be responsible for passage of flatus at coitus.

Adult↗

PubMed2006

Functional activity of the rectum: A conduit organ or a storage organ or both?

AIM: To investigate whether the degree of rectal distension could define the rectum functions as a conduit or reservoir. METHODS: Response of the rectal and anal pressure to 2 types of rectal balloon distension, rapid voluminous and slow gradual distention, was recorded in 21 healthy volunteers (12 men, 9 women, age 41.7 +/- 10.6 years). The test was repeated with sphincteric squeeze on urgent sensation. RESULTS: Rapid voluminous rectal distension resulted in a significant rectal pressure increase (P < 0.001), an anal pressure decline (P < 0.05) and balloon expulsion. The subjects felt urgent sensation but did not feel the 1st rectal sensation. On urgent sensation, anal squeeze caused a significant rectal pressure decrease (P < 0.001) and urgency disappearance. Slow incremental rectal filling drew a rectometrogram with a "tone" limb representing a gradual rectal pressure increase during rectal filling, and an "evacuation limb" representing a sharp pressure increase during balloon expulsion. The curve recorded both the 1st rectal sensation and the urgent sensation. CONCLUSION: The rectum has apparently two functions: transportation (conduit) and storage, both depending on the degree of rectal filling. If the fecal material received by the rectum is small, it is stored in the rectum until a big volume is reached that can affect a degree of rectal distension sufficient to initiate the defecation reflex. Large volume rectal distension evokes directly the rectoanal inhibitory reflex with a resulting defecation.

Adult↗

PubMed2006

Electro-orchidogram: a non-invasive diagnostic tool in testicular pathologies.

BACKGROUND: We investigated the hypothesis that the transcutaneous electro-orchidogram (EOG) can act as a diagnostic tool in testicular pathological conditions. MATERIAL/METHODS: Three electrodes were applied to the scrotal skin of 21 healthy volunteers (controls), 12 patients with acute epididymo-orchitis (EO), 8 with testicular torsion (TT), 10 with unilateral undescended testicle (UT), and 9 with testicular seminoma (TS). Recordings were performed before and 48 hours and 1, 3, and 6 months after treatment. Semen analysis was done 1, 3, and 6 months post-treatment. RESULTS: Recordings from healthy volunteers showed slow waves (SWs) with similar wave variables from the three electrodes of the same individual. Patients with EO exhibited increased SW variables (p<0.05) during acute stage, which normalized in 8 and diminished in 4 patients 1, 3, and 6 months after inflammatory process resolution. Post resolution, the 8 patients had normospermia and the 4 oligospermia. In TT, SWs were absent during torsion and after detorsion in 7 patients; SWs and semen normalized in 1 patient 6 months after detorsion. The UT showed absent SWs up to 6 months post-descent; semen remained oligospermic. Testicles with TS exhibited areas with SWs and silent areas. CONCLUSIONS: Testicles in the above pathological conditions showed electro-orchidographic changes associated with changes in semen character. Repeated EOG could demonstrate the progress of the pathological condition in the testicle. The non-invasive EOG may act as a diagnostic and follow-up tool in some testicular pathological conditions after further studies have been performed in this issue.

Adult↗

PubMed2006

Cavernosus muscle contraction during erection: is it voluntary or reflex, given the striated nature of the muscles?

The bulbo- and ischio-cavernosus muscles (BCM, ICM) contract in the rigid erection phase, leading to a suprasystolic cavernosal pressure. We investigated the hypothesis that the contraction of cavernosal muscles is reflexogenic despite their striated nature. The intracavernosal pressure (ICP) and the cavernosus muscles' electromyography (EMG) were recorded in 18 healthy volunteers in the flaccid and erectile phases. The test was repeated after separate anesthetization of the cavernosus muscles and the corpora cavernosa while the penis was in the rigid erection phase. The ICM and BCM showed no EMG activity with tumescence and full erection. When the ICP reached a mean of 148.6 +/- 9.4 cm H2O, both the ICM and BCM showed increased EMG activity. The suprasystolic pressure was intermittent and corresponded to the intermittent BCM and ICM contraction. Voluntary cavernosus muscle contraction did not increase the ICP at the different stages of erection. Anesthetization of the penis in the rigid erection phase led to disappearance of the cavernosus muscles' EMG activity, while bland gel application did not. Anesthetization of the 2 contracting cavernosus muscles, while the penis was in the rigid phase, produced an ICP drop to 69.5 +/- 7.6 cm H2O; repetition with saline did not affect the ICP. Cavernosus muscle contraction on corporal pressure elevation seems to be reflex and mediated through the corporo-cavernosal reflex (CCR). Changes in the evoked response amplitude would indicate a defect in the reflex pathway.

Adult↗

PubMed2006

The hypoactive corpora cavernosa with degenerative erectile dysfunction: a new syndrome.

BACKGROUND: In a group of 22 patients with erectile dysfunction, vasculogenic, neurogenic, endocrinologic or psychogenic investigations failed to find a cause for their erectile dysfunction. The electro-cavernosograms of these patients recorded a diminished activity. We investigated the hypothesis that diminished corpus cavernosum electromyography activity was the cause of erectile dysfunction in these patients. METHODS: The study comprised the above mentioned 22 patients (study group, 43.8 +/- 5.9 SD years) and 15 healthy volunteers (control group, 41.8 +/- 5.1 SD years). The electro-cavernosograms were recorded in the flaccid, erectile and detumescent phases by 2 electrodes inserted into the corpus cavernosum. RESULTS: The electro-cavernosogram of the healthy volunteers registered in the flaccid phase regular slow waves and random action potentials. The wave variables declined significantly in the erectile phase (p < 0.01). In the study group, the slow wave variables in the flaccid phase exhibited a significant decrease (p < 0.05) compared to the healthy volunteers, and the rhythm was irregular. Erection did not occur with sildenafil administration or intracavernosal papaverine injection, and penile implant was performed. Biopsy examination showed degenerated muscle fibers, and fragmented collagen and elastic fibers with areas of fibrosis. CONCLUSION: A novel concept of the cause of erectile dysfunction was presented. Corpora cavernosa showed degenerative changes on histopathologic examination and exhibited diminished electromyography activity. They did not respond to sildenafil administration or intracavernosal papaverine injection. Penile implants were the only treatment. The condition is given the name 'hypoactive corpus cavernosum'. The cause of corpus cavernosum degenerative changes needs further study.

Adult↗

PubMed2006

Does the composition of voided urine reflect that of the renal pelvis?

Studies have shown that the urothelium has a transport function and that urine composition changes on its way through the urinary tract. In this study, we investigated the hypothesis that the composition of voided urine differs from and does not reflect that of the renal pelvis. Urine samples were obtained from the renal pelvis and voided urine of 18 healthy volunteers (mean age 36.2+/-5.1 SD years, 10 men, 8 women). The pH was determined using a pH electrode, osmolality by means of micro-osmometry and Na and K using flame photometry. In comparison to the urine of the renal pelvis, voided urine showed significant increases in pH, osmolality and Na and K concentrations (P<0.05 for each). There were no significant differences in gender and age. This study has demonstrated that the pH, osmolality, Na and K of voided urine differ significantly from the values in the renal pelvis. Urine composition is thus modified as it passes through the urinary tract, which would support the concept of a dynamic urothelium. The composition of voided urine does not seem to compare to renal pelvic urine. This concept needs to be considered in urine analysis evaluation and its relation to renal function.

Adult↗

PubMed2006

Straining-cremasteric reflex: identification of a new reflex and its role during increased intra-abdominal pressure.

The cremasteric muscle (CM) being composed of fleshy muscle bundles constitutes the active component of the fasciomuscular tube of the spermatic cord. On contraction, the CM compresses the cord veins pushing the blood in the pampiniform plexus to the abdominal veins. The role of the CM during increased intra-abdominal pressure (IAP) could not be traced in the literature. We investigated the hypothesis that the CM contracts upon IAP increase so as to support the cord veins and prevent abdominal veins reflux into them. Thirty-two healthy male volunteers (mean age 40.2 +/- 11.2 SD years) were studied. The IAP was recorded by a manometric catheter introduced into the rectum. The CM response to straining (sudden by coughing and slow by Valsalva's maneuver) was registered by a needle electrode introduced into the muscle. The response was recorded again after individual anesthetization of the CM and rectum. The test was repeated using saline instead of lidocaine and was performed on both sides. Straining (sudden or slow sustained) effected increase of the rectal pressure and CM EMG. The more the rectal pressure was increased by straining, the more the CM EMG was increased. The CM EMG response disappeared after prolonged or repeated successive straining. The CM did not respond to straining after individual anesthetization of the rectum and CM but did respond to saline administration. The response was similar from muscles on both sides. Increased CM EMG on straining postulates a reflex relationship which we call the 'straining-cremasteric reflex' (SCR). We suggest that this reflex, which results in CM contraction, supports the spermatic cord veins against the increase of the IAP induced by straining and against the tendency of venous reflux from the abdominal veins. The SCR may prove of diagnostic significance in neurogenic disorders provided further studies are performed in this respect.

Abdomen↗

PubMed2006

Contractile activity of the prostate at ejaculation: an electrophysiologic study.

OBJECTIVES: To investigate the hypothesis that the prostate contracts at ejaculation to push its secretions into the urethra. Although it has been mentioned that the prostate contracts at ejaculation, a report of this finding could not be traced in published studies. METHODS: The electromyographic activity of 8 canine prostates was recorded by applying an electrode to the prostate. The prostatic urethral pressure was simultaneously measured by means of a manometric catheter. The prostatic electromyographic and urethral pressures were recorded at rest and on ejaculation by penile electrovibration. RESULTS: The prostatic slow waves (SWs) and action potentials (APs), as well as the urethral pressure at rest, showed a significant increase during the ejaculatory bouts (P < 0.05 and P < 0.05, respectively). The SWs, APs, and pressure increase occurred simultaneously with each bout of ejaculatory spurt, which occurred at mean intervals of 1.1 +/- 0.02 seconds and a number of 4.6 +/- 1.2 bouts. CONCLUSIONS: The electric waves discharged from the prostate at rest seemed to produce prostatic contractions, which cause prostatic urethral pressure increases. At ejaculation, the intermittent increase of the wave variables and urethral pressure coincided with the ejaculatory spurts, apparently denoting intermittent prostatic smooth muscle contractions. These contractions seem to squeeze the prostatic secretions into the prostatic urethra.

Animals↗

PubMed2006

Study of the role of the transverse perineal muscles during rectal filling.

BACKGROUND: The function of perineal muscles at defecation is poorly addressed in the literature. We investigated the hypothesis that rectal distension effects reflex contraction of four perineal muscles. PATIENT/METHODS: After rectal balloon distension with carbon dioxide in increments of 20 ml, the responses of electromyographic (EMG) activity of superficial (STPM) and deep (DTPM) transverse perineal muscles as well as the rectal pressure were recorded in 22 healthy volunteers (14 men, age 37.2+/-6.3 years). Responses were registered again after individual anesthetization of rectum and transverse perineal muscles. Tests were repeated using saline instead of lidocaine. RESULTS/FINDINGS: Rectal balloon distension in big volumes effected increase of the transverse perineal muscles' EMG activity and rectal pressure. The more the rectum was distended, the more the rectal pressure and EMG activity of the transverse perineal muscles were increased. The latency showed a gradual decrease upon incremental rectal distension increase. Transverse perineal muscles did not respond to rectal distension after the rectum and perineal muscles had been individually anesthetized, but it responded to saline administration. Response of the muscles was similar in both sides. INTERPRETATION/CONCLUSION: Increase of rectal pressure increases EMG activity of transverse perineal muscles. This action seems mediated through a reflex which we call 'recto-perineal reflex'. Contraction of transverse perineal muscles at defecation presumably supports the perineal floor. It also protects transverse perineal muscles against straining-produced high pressure that is transmitted through the recto-vaginal/-vesical cul de sac to the perineum which may sag down and share in genesis of perineocele, enterocele, or sigmoidocele.

Adult↗

PubMed2006

Role of the rectosigmoidal junction in fecal continence: concept of the primary continent mechanism.

HYPOTHESIS: At mass contraction of the descending colon, the colonic contents stop at the sigmoid colon (SC) and do not pass directly to the rectum. We investigated the hypothesis that a continent mechanism seems to exist at the rectosigmoidal junction (RSJ), preventing the direct passage of stools from the descending colon to the rectum. METHODS: The SC in 16 healthy volunteers (mean +/- SD age, 38.6 +/- 10.2 years; 9 men and 7 women) was distended with an isotonic sodium chloride solution-filled balloon, and the pressure response of the RSJ and the rectum was recorded at rapid and gradual filling of the balloon. The test was repeated after the SC and RSJ were anesthetized separately. RESULTS: Rapid SC balloon distension with a mean +/- SD of 52.1 +/- 3.6 mL of isotonic sodium chloride solution effected an RSJ pressure increase to a mean +/- SD of 67.8 +/- 18.4 cm H(2)O (P<.01) with no rectal pressure response (P>.05). Slow SC filling produced a progressive increase in RSJ pressure but no rectal pressure change. At a mean +/- SD SC distending volume of 86.3 +/- 4.1 mL, the RSJ pressure decreased to 9.6 +/- 2.8 (P<.01), and the balloon was dispelled to the rectum; rectal pressure increased (P<.001), and the balloon was expelled to the exterior. The RSJ pressure did not respond to distension of the anesthetized SC. CONCLUSIONS: Contraction of the RSJ at rapid SC distension with big volumes implies a reflex relationship that we call the RSJ guarding reflex. This reflex seems to prevent the descending colon contents from passing directly to the rectum. It is considered the first continent reflex and may serve as an investigative tool in the study of fecal incontinence.

Adult↗

PubMed2006

The effect of esophageal and gastric distension on the crural diaphragm.

BACKGROUND: The mechanism of prevention of gastric reflux into the esophagus is not exactly known. The lower esophagus has a barrier function provided by the lower esophageal sphincter. We investigated the hypothesis that the crural diaphragm shares in the barrier function not only mechanically but also actively through a crural-esophageal-gastric reflex action. METHODS: The study was performed during repair of abdominal ventral and incisional hernias in 20 subjects (11 men, 9 women; age 38.6+/-4.8 years). The electromyographic response of the crural diaphragm to individual balloon distension of esophagus and stomach was recorded by means of a needle electrode inserted into the crural diaphragm and connected to an electromyographic apparatus. The recordings were repeated after separate crural, esophageal, and gastric anesthetization. RESULTS: The crural diaphragm exhibited basal motor unit action potentials, which decreased on esophageal distension (P<0.001) after a mean latency of 17.3+/-2.8 SD ms. The crural diaphragm response to esophageal distension did not occur after the crural diaphragm or esophagus was anesthetized. Gastric distension effected an increase of crural diaphragm electromyographic activity with a mean latency of 18.4+/-4.6 ms; this effect could not be achieved after the crural diaphragm or stomach was anesthetized. CONCLUSIONS: The crural diaphragm has a resting tone that relaxes after esophageal distension and contracts after gastric distension. This sphincter-like action of the crural diaphragm appears to be a reflex and is mediated through the esophagocrural inhibitory and gastrocrural excitatory reflexes. The crural diaphragm seems to share actively in the gastroesophageal competence mechanism.

Action Potentials↗