Micturition (The Guyton and Hall physiology)Maryam Fida
The process by which the urinary bladder empties when it becomes filled.
It is a reflex process
ANATOMY OF URINARY BLADDER BODY = in which urine is collected
NECK = funnel shaped extension and connecting with the urethra.
URETHRAL SPHINCTER.
1. INTERNAL URETHRAL SPHINCTER.
made up of detrusor muscle
2. EXTERNAL URETHRAL SPHINCTER.
made up of skeletal muscle fiber.
EXTERNAL URETHRAL SPHINCTER is responsible for voluntary control of micturition
The walls of the ureter contain smooth musle and are innervated by both sympathetic and parasympathetic nerves.
Parasympathetic stimulation increases peristaltic contraction .
Sympathetic stimulation inhibited MICTURITION REFLEX Filling of urinary bladder 300 – 400 ml
|
stimulation of sensory stretch receptors
present on the wall of bladder
|
Afferent impulses pass via pelvic nerve
|
reaches the sacral segments of spinal cord
|
synapses with postganglionic neuron
|
Efferent impulses via pelvic nerve
causes contraction of detrusor muscle
and relaxation of internal sphincter
|
flow of urine in to urethra and
stimulation of stretch receptors present
in urethra
|
it send afferent impulses via pelvic nerve
|
Inhibition of pudendal nerve
|
Relaxation of external sphincter
|
voiding of urine
Once a micturition begins ,, it is a “self regenerative “.
THAT IS,
the initial contraction of bladder
further activates the receptors to
causes still further increase in sensory
impulses from the bladder and urethra.
These impulses in turn further increases in reflex contraction of bladder.
05.26.09(b): Development of the Respiratory System and DiaphragmOpen.Michigan
Slideshow is from the University of Michigan Medical
School's M1 Embryology sequence
View additional course materials on Open.Michigan:
openmi.ch/med-M1Embryology
The vas deferens, also called ductus deferens, is part of the male reproductive system of many vertebrates; these ducts transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. It is a partially coiled tube that exits the abdominal cavity through the inguinal canal.
Micturition (The Guyton and Hall physiology)Maryam Fida
The process by which the urinary bladder empties when it becomes filled.
It is a reflex process
ANATOMY OF URINARY BLADDER BODY = in which urine is collected
NECK = funnel shaped extension and connecting with the urethra.
URETHRAL SPHINCTER.
1. INTERNAL URETHRAL SPHINCTER.
made up of detrusor muscle
2. EXTERNAL URETHRAL SPHINCTER.
made up of skeletal muscle fiber.
EXTERNAL URETHRAL SPHINCTER is responsible for voluntary control of micturition
The walls of the ureter contain smooth musle and are innervated by both sympathetic and parasympathetic nerves.
Parasympathetic stimulation increases peristaltic contraction .
Sympathetic stimulation inhibited MICTURITION REFLEX Filling of urinary bladder 300 – 400 ml
|
stimulation of sensory stretch receptors
present on the wall of bladder
|
Afferent impulses pass via pelvic nerve
|
reaches the sacral segments of spinal cord
|
synapses with postganglionic neuron
|
Efferent impulses via pelvic nerve
causes contraction of detrusor muscle
and relaxation of internal sphincter
|
flow of urine in to urethra and
stimulation of stretch receptors present
in urethra
|
it send afferent impulses via pelvic nerve
|
Inhibition of pudendal nerve
|
Relaxation of external sphincter
|
voiding of urine
Once a micturition begins ,, it is a “self regenerative “.
THAT IS,
the initial contraction of bladder
further activates the receptors to
causes still further increase in sensory
impulses from the bladder and urethra.
These impulses in turn further increases in reflex contraction of bladder.
05.26.09(b): Development of the Respiratory System and DiaphragmOpen.Michigan
Slideshow is from the University of Michigan Medical
School's M1 Embryology sequence
View additional course materials on Open.Michigan:
openmi.ch/med-M1Embryology
The vas deferens, also called ductus deferens, is part of the male reproductive system of many vertebrates; these ducts transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. It is a partially coiled tube that exits the abdominal cavity through the inguinal canal.
The skin is divided into two parts: the superficial part, the
epidermis; and the deep part, the dermis (Fig. 1.4). The
epidermis is a stratified epithelium whose cells become flat
tened as they mature and rise to the surface. On the palms of
the hands and the soles of the feet, the epidermis is extremely
thick, to withstand the wear and tear that occurs in these
regions. In other areas of the body, for example, on the ante
rior surface of the arm and forearm, it is thin. The dermis is
composed of dense connective tissue containing many blood
vessels, lymphatic vessels, and nerves. It shows considerable
variation in thickness in different parts of the body, tending
to be thinner on the anterior than on the posterior surface.
It is thinner in women than in men. The dermis of the skin
is connected to the underlying deep fascia or bones by the
superficial fascia, otherwise known as subcutaneous tissue.
The skin over joints always folds in the same place, the
SKIN CREASES (Fig. 1.5). At these sites, the skin is thinner
than elsewhere and is firmly tethered to underlying struc
tures by strong bands of fibrous tissue.
The appendages of the skin are the nails, hair follicles,
sebaceous glands, and sweat glands.
The nails are keratinized plates on the dorsal surfaces of
the tips of the fingers and toes. The proximal edge of the
plate is the root of the nail (see Fig. 1.5). With the exception
of the distal edge of the plate, the nail is surrounded and
overlapped by folds of skin known as nail folds. The sur
face of skin covered by the nail is the nail bed (see Fig. 1.5).
Hairs grow out of follicles, which are invaginations
of the epidermis into the dermis (see Fig. 1.4). The folli
cles lie obliquely to the skin surface, and their expanded
extremities, called hair bulbs, penetrate to the deeper part
of the dermis. Each hair bulb is concave at its end, and
EMBRYOLOGY OF KUB AND ITS CINICAL SIGNIFICANY(1).pptxvinodkrish2
Indications
This view is useful in visualizing calcifications anywhere along the renal tract (i.e. kidneys, ureters, bladder, urethra). It is also used as baseline/interval images in contrast studies (i.e. intravenous urography).
Patient position
the patient is supine, lying on their back, either on the x-ray table (preferred) or a trolley
patients should be changed into a hospital gown, with radiopaque items removed (e.g. belts, zippers, buttons, ECG electrodes)
the patient should be free from rotation; both shoulders and hips equidistant from the table/trolley
the x-ray is taken on full inspiration
this causes the diaphragm to contract, hence compressing the abdominal organs, allowing all renal contents to be visualized on a single image
ADVERTISEMENT: Supporters see fewer/no ads
Technical factors
AP projection
centering point
the midsagittal point (equidistant from each ASIS) at the level of the iliac crest
collimation
laterally to the lateral abdominal wall
superior to the upper kidney pole
inferior to the inferior pubic rami
orientation
portrait
detector size
35 cm x 43 cm
exposure
70-80 kVp
30-120 mAs; AEC should be used if available
SID
100 cm
grid
yes
Image technical evaluation
ensure visualization of the upper poles of both kidneys even if the diaphragm was not imaged
the abdomen should be free from rotation with symmetry of the:
ribs (superior)
iliac crests (middle)
obturator foramen (inferior)
Practical points
In male patients, it is acceptable to perform imaging with collimation extending inferior to the pubic symphysis as there may be renal calculi in the urethra too.
Exposure will need to be adjusted according to the imaging system (CR or DR) and patient size. Where possible, a higher kVp should be used in the evaluation of radiopaque objects.
References
Incoming Links
Related articles: Radiographs (adult)
Promoted articles (advertising)
Cases and figures
Figure 1: location of kidneys (annotated image)
Case 1: normal KUB
Case 2: normal intravenous urogram
Case 3: right staghorn calculus
Case 4: urethral calculus
Case 5: left renal calculus
Case 6: medullary nephrocalcinosis with ureteric calculi
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ABOUTIndications
This view is useful in visualizing calcifications anywhere along the renal tract (i.e. kidneys, ureters, bladder, urethra). It is also used as baseline/interva
In this presentation the development of Small intestine and Pancreas has been discussed. The viewer would be able to understand the concept of physiological herniation and rotation of the Primary intestinal loop with in the connecting stalk.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
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Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
4. A. LATERAL VIEW OF A 4-WEEK EMBRYO SHOWING THE RELATIONSHIP PRIMORDIAL GUT TO YOLK SAC.
B. DRAWING OF MEDIAN SECTION OF THE EMBRYO SHOWING EARLY DIGESTIVE SYSTEM AND ITS BLOOD
SUPPLY.
THE PRIMORDIAL GUT IS A LONG TUBE EXTENDING THE LENGTH OF THE EMBRYO. ITS BLOOD VESSELS ARE
DERIVED FROM THE VESSELS THAT SUPPLIED THE YOLK SAC.
5. MIDGUTDERIVATIVES ARE
The small intestine, including most of the
duodenum ( the part caudal to the major
duodenal papilla )
The caecum; appendix; ascending colon and the
right half or two- third of the transverse colon
All these midgut derivatives are supplied by the
superior mesenteric artery
6. FORMATION OF THE MIDGUT LOOP [ SHADED ]
NOTE – HOW THE SUPERIOR MESENTERIC ARTERY AND VITELLINE
DUCT FORM AN AXIS FOR THE FUTURE ROTATION OF THE MIDGUT
LOOP
7. THE MIDGUT LOOP IS SUSPENDED FROM
THE DORSAL ABDOMINAL WALL BY AN
ELONGATED MESENTERY.
AS IT ELONGATES, THE VENTRAL U –
SHAPED LOOP OF GUT ( MIDGUT LOOP )
PROJECTS INTO THE REMAINS OF THE
EXTRAEMBRYONIC COELOM IN THE
PROXIMAL PART OF THE UMBILICAL CORD
AT THE END OF THE 5TH WEEK.
AT THIS STAGE, THE INTRAEMBRYONIC
COELOM ( PERITONEAL CAVITY )
COMMUNICATES WITH THE
EXTRAEMBRYONIC COELOM AT THE
UMBILICUS.
8. PHYSIOLOGICAL UMBILICAL HERNIATION OCCURS AT THE
BEGINNING OF 6TH WEEK.
The midgut loop communicates with the yolk sac through the narrow yolk stalk or vitelline duct ( vitello-
intestinal duct ) until the 10th week. So, the herniated intestine is derived from the midgut loop in the
proximal part of the umbilical cord.
Umbilical herniation occurs because there is not enough room in the abdomen for rapidly growing midgut.
The shortage of space is caused by the relatively massive liver and the 2 kidneys
9. THE MIDGUT LOOP HAS A CRANIAL LIMB AND A CAUDAL LIMB. THE YOLK STALK IS ATTACHED TO THE APEX OF THE MIDGUT
LOOP WHERE THE 2 LIMBS JOIN.
THE CRANIAL LIMB GROWS RAPIDLY AND FORMS SMALL INTESTINAL LOOPS. THE CAUDAL LIMB UNDERGOES VERY LITTLE
CHANGE EXCEPT FOR DEVELOPMENT OF THE CAECAL DIVERTICULUM ( THE PRIMORDIUM OF THE CECUM AND APPENDIX.
10. ROTATION OF MIDGUT
LOOP
• While it is in the umbilical cord, the midgut loop rotates
90 degrees counterclockwise around the axis of the
superior mesenteric artery and yolk stalk. This brings the
cranial limb of the midgut loop to the right and the caudal
limb to the left.
• During rotation the cranial limb elongates and forms
jejunum & ileum ( intestinal loops)
11. FIXATION OF INTESTINE
DURING THE 10TH WEEK, THE INTESTINES RETURN TO
THE ABDOMEN. IT IS NOT KNOWN WHAT IS THE
CAUSES. HOWEVER, THE DECREASE IN THE SIZE OF THE
LIVER AND KIDNEYS AND THE ENLARGEMENT OF THE
ABDOMINAL CAVITY ARE IMPORTANT FACTORS. THIS
PROCESS IS CALLED REDUCTION OF THE
PHYSIOLOGICAL MIDGUT HERNIA.
THE SMALL INTESTINE ( FORMED FROM THE CRANIAL
LIMB ) RETURNS FIRST AND PASSES POSTERIOR TO THE
SUPERIOR MESENTERIC ARTERY AND OCCUPIES THE
CENTRAL PART OF THE ABDOMEN.
AS THE LARGE INTESTINE RETURNS, IT UNDERGOES A
FURTHER 180 DEGREE COUNTERCLOCKWISE ROTATION.
13. • Later it comes to occupy the right side of the abdomen.
• The ascending colon becomes recognizable as the posterior
abdominal wall progressively elongates. The cecum is
rotating to its normal position in the lower right quadrant of
the abdomen.
• Rotation of the stomach and duodenum causes the
duodenum and pancreas to fall to the right. The enlarged
colon presses the duodenum against the posterior abdominal
wall. As a result, most of the duodenal mesentery is
absorbed and the duodenum, except for about the first 2.5
cm ( derived from the foregut ), has no mesentery and lies
retroperitoneally.
14. AT FIRST THE DORSAL MESENTERY IS IN THE MEDIAN PLANE. AS
THE INTESTINES ENLARGE, LENGTHEN AND ASSUME THEIR FINAL
POSITION, THEIR MESENTERIES ARE PRESSED AGAINST THE
POSTERIOR ABDOMINAL WALL. SO, THE MESENTERY OF THE
ASCENDING COLON FUSES WITH THE PARIETAL PERITONEUM ON
THIS WALL AND DISAPPEARS. THE DESCENDING COLON ALSO
BECOMES RETROPERITONEAL
Other derivatives of the midgut loop ( jejunum
& ileum ) retain their mesenteries. The
mesentery is at first attached to the median
plane of the posterior abdominal wall.
After the mesentery of the ascending colon
disappears, the fan- shaped mesentery of the
small intestine acquires a new line of
attachment that passes from the
duodenojejunal junction inferolaterally to the
ileocecal junction.
15. Succesive stages in the development of caecum and
appendix
at birth – appendix is relatively long and is continuous with the apex of the caecum.
adult – appendix is now relatively short and lies on medial side of the caecum. In about 64% of the
people, the appendix is located posterior to the caecum (retrocaecal) or posterior to the ascending colon
(retrocolic). The tenia colia is a thickend band of longitudinal muscle in the wall of colon which ends at
the base of appendix.
16. THE CECAL DIVERTICULUM ( PRIMORDIUM OF THE CECUM AND VERMIFORM
APPENDIX ) APPEARS IN THE 6TH WEEK AS A SWELLING ON THE
ANTIMESENTERIC BORDER OF THE CAUDAL LIMB OF THE MIDGUT LOOP.
THE APEX OF THE CECAL DIVERTICULUM DOES NOT GROW AS RAPIDLY AS
THE REST OF IT. THUS, THE APPENDIX IS INITIALLY A SMALL
DIVERTICULUM OF THE APEX OF THE CECUM.
THE APPENDIX INCREASES RAPIDLY IN LENGTH SO THAT AT BIRTH IT IS A
RELATIVELY LONG TUBE ARISING FROM THE DISTAL END OF THE CECUM.
AFTER BIRTH THE WALL OF THE CECUM GROWS UNEQUALLY, WITH THE
RESULT THAT THE APPENDIX COMES TO ENTER ITS MEDIAL SIDE. THE
APPENDIX MAY PASS POSTERIOR TO THE CAECUM ( RETROCECAL ) OR
COLON ( RETROCOLIC ). IT MAY DESCEND OVER THE BRIM OF THE PELVIS
( PELVIS APPENDIX ).
IN ABOUT 64 % OF PEOPLE THE APPENDIX IS LOCATED RETROCECALLY
17. CONGENITAL OMPHALOCELE
THIS ANOMALI IS PERSISTENCE OF THE HERNIATION OF
ABDOMINAL CONTENTS INTO THE PROXIMAL PART OF THE
UMBILICAL CORD AND FAILURE OF THE INTESTINE TO
RETURN TO THE ABDOMINAL CAVITY FROM THE
EXTRAEMBRYONIC COLEOM DURING THE 10TH WEEK.
THE COVERING OF THE HERNIAL SAC IS THE EPITHELIUM
OF UMBILICAL CORD ( A DERIVATIVE OF THE AMNION ).
HERNIATION OF THE INTESTINES INTO THE CORD
OCCURS IN ABOUT 1 OF 5000 BIRTHS AND HERNIATION OF
THE LIVER AND INTESTINES IN 1 OF ABOUT 10000 BIRTHS.
THE SIZE OF THE HERNIA DEPENDS ON ITS CONTENTS.
WHEN THERE IS SMALL ABDOMINAL CAVITY, THERE IS
OMPHALOCELE.
IMMEDIATE SURGICAL REPAIR IS REQUIRED
18.
19. THE YOLK STALK. IT TYPICALLY APPEARS
AS A FINGERLIKE POUCH ABOUT 3 TO 6
CM LONG THAT ARISES FROM THE
ANTIMESENTERIC BORDER OF THE
ILEUM 40 T0 50 CM FROM THE
ILEOCECAL JUNCTION.
IT IS COMMON. MECKEL DIVERTICULUM
OCCURS IN 2 TO 4 % OF PEOPLE AND IS
3 TO 5 TIMES MORE PREVALENT IN
MALES THAN FEMALES. WHEN IT
INFLAMES, IT CAUSES SYMPTOMS THAT
MIMIC APPENDICITIS.
THE WALL OF THE DIVERTICULUM
CONTAINS ALL LAYERS OF ILEUM AND
MAY CONTAIN SMALL PATCHES OF
GASTRIC AND PANCREATIC TISSUES.
20. AN ILEAL DIVERTICULUM MAY BE CONNECTED TO THE UMBILICUS BY A FIBROUS
CORD OR AN OMPHALOENTERIC FISTULA WHICH RESULTS FROM PERSISTENCE OF
THE ENTIRE INTRAABDOMINAL PORTION OF THE YOLK STALK ( VITELLINE DUCT ).
ON THE FIBROUS REMNANT OF THE OF THE YOLK STALK A VITELLINE CYSTS IS FORMED.
UMBILICAL SINUS RESULTS FROM THE PERSISTENCE OF THE YOLK STALK NEAR THE
UMBILICUS. IT IS USUALLY APPEAR WITH VOLVULUS OF THE DIVERTICULUM.
THE YOLK STALK HAS PERSISTED AS A FIBROUS CORD CONNECTING THE ILEUM WITH THE
UMBILICUS AND CONTAINING A PERSISTENT VITELLINE ARTERY .
21. HINDGUT
IT IS DERIVATIVES ARE :
- THE LEFT ONE THIRD TO ONE HALF OF THE TRANSVERSE COLON; THE
DESCENDING COLON ; SIGMOID COLON; RECTUM AND THE SUPERIOR PART OF THE
ANAL CANAL.
- THE EPITHELIUM OF THE URINARY BLADDER AND MOST OF THE URETHRA.
- THESE DERIVATIVES ARE SUPPLIED BY THE INFERIOR MESENTERIC ARTERY.
- THE DESCENDING COLON BECOMES RETROPERITONEAL AS ITS DORSAL
MESENTERY FUSES WITH THE PERITONEUM ON THE LEFT POSTERIOR ABDOMINAL
WALL AND THEN DISAPPEARS.
- THE MESENTERY OF THE SIGMOID COLON IS RETAINED BUT IT IS SHORTER
THAN IN THE EMBRYO.
22. CLOACA
THE CLOACA IS THE EXPANDED TERMINAL PART OF THE HINDGUT WHICH RECEIVES THE ALLANTOIS VENTRALLY ( A FINGERLIKE
DIVERTICULUM ).
IT IS AN ENDODERM- LINED CHAMBER THAT CONTACT WITH THE SURFACE ECTODERM AT THE CLOACAL
MEMBRANE. THIS MEMBRANE IS COMPOSED OF ENDODERM OF THE CLOACA AND ECTODERM OF THE
PROCTODEUM ( ANAL PIT ).
THE CLOACA IS DIVIDED INTO DORSAL AND VENTRAL PARTS BY A WEDGE OF MESENCHYME ( THE URORECTAL
SEPTUM ) WHICH DEVELOPS IN THE ANGLE BETWEEN THE ALLANTOIS AND HINDGUT.
AS THE SEPTUM GROWS TOWARD THE CLOACAL MEMBRANE, IT DEVELOPS FORKLIKE EXTENSIONS.
THE 2 PARTS ARE : A- RECTUM AND CRANIAL PART OF THE ANAL CANAL DORSALLY.
B- UROGENITAL SINUS VENTRALLY.
23. RADIOGRAPHY OF COLON AFTER A BARIUM ENEMA IN
A ONE MONTH OLD INFANT WITH CONGENITAL
MEGACOLON OR HIRSCHSPRRUNG DISEASE. THE
AGANGLIONIC DISTAL SEGMENT (RECTUM AND DISTAL
SIGMOID COLON) IS NARROW, WITH DISTENDED
NORMAL GANGLIONIC BOWEL, FULL OF FACEAL
MATERIAL, PROXIMAL TO IT.
Congenital Megacolon ( Hirschsprung
Disease )
It is a dominant inherited multigenic disorder. It is the most common
cause of neonatal obstruction of the colon and occurs for about 33% .
Males are affected more often than females ( 4- 1 ).
A part of colon is dilated because oF absence of autonomic ganglia
cells in myenteric plexus distal to the dilated segment of colon.
The enlarged colon has normal number of ganglion cells. The
dilatation results from failure of peristalsis in aganglionic segment (
transition zone ) which prevents movement of the intestinal
contents.
In most cases only the rectum and sigmoid colon are involved. Also,
ganglia may be absent from more proximal parts of the colon.
It results from failure of the neural crest cells to migrate into the wall
of the colon during the 5th to 7th weeks. This results in failure of
parasympathetic ganglion cells to develop in the Auerbach and
Meissner plexuses.
The cause of failure of some neural crest cells to complete their