Yr3 Sem1 Flashcards
Introduce the anterolateral Abdominal Wall
S: musculo-aponeurotic wall
F: Contracts to increase intra-abdominal pressure and provide trunk movement. Also distends to accommodate expansion due to ingestion, pregnancy, fat deposition or pathology
Location: found anterolateral over the abdominal cavity extending from the thoracic cage to the pelvic girdle
External Oblique:
O: external surface of ribs 5-12
I: linea alba, pubic tubercle, anterior 1/2 iliac crest
N: thoracoabdominal n/subcostal n
A: flexion and rotation (contralateral) of the trunk , compression and support of the viscera
Fibre Direction: inferior and medial
Internal Oblique:
O: Thoracolumbar fascia, Anterior 2/3 iliac crest, lateral 1/2 inguinal ligament
I: inferior border of ribs 10-12, linea alba, pectineal line via conjoint tendon
N: thoracoabdominal n/ first lumbar n
A: flexion and rotation (ipsilateral) of the trunk , compression and support of the viscera
Fibre Direction: changes around the ASIS. inferior to: run inferior and medial, At level: transversals medial, superior to: superior and medial
Transversals Abdominals:
O: inferior surface of costal cartilage 7-12, thoracolumbar fascia, iliac crest and lateral 1/3 inguinal ligament
I: linea alba, pubic crest and pectineal line via the conjoint tendon
N: thoracoabdominal n/ first lumbar n
A: compression and support of the visceral
Fibre Direction: transverse medial, inferiorly runs inferior and medial with the internal oblique aponeurosis
Rectus Abdominus
O: Pubic symphysis and pubic crest
I: xiphoid process and costal cartridges 5-7
N: thoracoabdominal n
A: Flexes the trunk, compresses and supports the abdominal viscera
Special feature: enclosed in the rectus sheath and anchored transversely
What is the rectus sheath
is a strong but incomplete compartment in the aponeurosis between the anterolateral abdominal wall muscles. It contains the rectus abdominis, pyramidalis, superior and inferior epigastric arteries and veins, lymphatic vessels and distal portions of the thoracoabdominal nerves. It is formed by the decussation and interwoven aponeuroses of external and internal oblique and transverse abdominal muscles
What is the line Alba
Along the length of the rectus sheath at the anterior median line the fibres of both the anterior and posterior walls interlace to form a strong median lattice running from the xiphoid process, narrowing at the level of the umbilicus to attach at the pubic symphysis
Introduce the Inguinal Canal
S: in an anatomical passageway
F: serves as a retinaculum for muscular and neuromuscular structures that pass deep to the thigh
L: runs in an oblique inferior and medial direction across the anterolateral abdominal wall.
What are the borders of the Inguinal Canal
Anterior: aponeurosis of the external oblique
Posterior: transversalis fascia and conjoint tendon of internal oblique and transverse abdominal
Floor: inguinal ligament
Roof: fibres of the internal oblique and transverse abdominals
deep inguinal ring: found in the transversalis fascia laterally
Superficial inguinal ring: found medially in the external oblique aponeurosis
What are the contents of the inguinal canal
nerves, vessels, lymphatics
Males: spermatic cord
Females: round ligament of the uterus
Introduce the Parietal Peritoneum
S: a double layer serous membrane
F: covers and contains the contents of the abdominal cavity
L: found on the internal surface of the abdominal wall
two layers: parietal and visceral, the parietal is the outer most layer and sensitive to pain, temperature, pressure and touch receiving blood and nerve supply from the same region as the wall it sits against. the visceral peritoneum covers the abdominal viscera and is sensitive only to stretch and tearing. receives blood and nerve supply from the organ it covers. These layers are separated by the peritoneal cavity
Describe the peritoneal cavity
is a potential space between the two layers of the peritoneum. it is empty except for a thin layer of fluid that keeps the peritoneal surfaces moist and prevents friction.
it contains leukocytes and antibodies that resist infection.
Describe Intra and Extra peritoneal organs
Intra: are almost completely covered with visceral peritoneum and are connected to the posterior abdominal wall by mesenteries
Extra: are external or posterior to the parietal peritoneum and only partially covered by the peritoneum, usually just one surface.
What are the different parts of the peritoneum
Mesenteries: double layers of peritoneum that are continuous with the parietal and visceral peritoneum, resulting from invagination by organs. it connects organs to the posterior abdominal wall, and provides a passage for neuromuscular communication
Lesser Momentum: is a double layered fold of peritoneum that connects the lesser curvature of the stomach and proximal duodenum to the the liver at the fissure of the ligamentum venous and portages hepatic.
Greater Omentum: is a four-layers fold of peritoneum that hangs down from the greater curvature of the stomach and proximal duodenum. It descends to fold back and attach to the anterior surface of the transverse colon and its mesentery.
What are peritoneal ligaments?
are double-layered aspects of peritoneum that connect an organ with another organ or to the abdominal wall
What is the blood supply to the abdominal wall
Reflects the arrangement of the muscles. they have an oblique, circumferential pattern.
Superior epigastric a: direct continuation of the internal thoracic artery. Enters the rectus sheath through the posterior layer and supplies the superior rectus abdomens and anastomoses with the inferior epigastric
Inferior epigastric: arises from the external iliac artery superior to the inguinal ligament. runs superior to the transversalis fascia to enter the rectus sheath below the arcuate line.
What are the branches of the abdominal aorta
Celiac trunk (level of T12) Superior Mesenteric (L1) Inferior Mesenteric (L3) Suprarenal (L1) Paired Renal (L1/2) paired Gonadal (ovarian or testicular) (L2) paired
What are the branches of the celiac trunk and what do they supply
common hepatic > splits into the proper hepatic and gasproduodenal with right gastric branch (lesser curvature) > proper hepatic splits into Lt and Rt to supply liver lobes/ gasproduodenal branches into right gastro-omental (greater curvature), superior anterior/posterior pancreatiocduodenal (pylorus, duodenum and head of pancreas)
left gastric supplies the lesser curvature
splenic > gives off pancreatic branches and short gastric (fundus of stomach) before supplying the spleen
What are the branches of the superior mesenteric artery and what do they supply
iliocolic artery (iliececal junction, ceacum) > appendicular artery (appendix)
right colic artery (ascending colon)
middle colic artery (hepatic flexure and transverse colon)
intestinal arteries (10-15 br. to small intestines)
inferior anterior/posterior pancreaticoduodenal artery (duodenum/head of pancreas)
What is the venous drainage of the abdominal wall
superior epigastric/vessels from muscle-phrenic vessels of internal thoracic vessels
inferior epigastric/deep circumflex epigastric vessels from femoral and saphenous veins
11th posterior intercostal vessels
what is the main venous drainage of the abdominal
inferior vena cava - begins at the level of L5 at union of the common iliac veins to the canal opening in the diaphragm to the heart
portal vein - is the visceral drainage of the abdominal into the liver to the IVC
what are the main lymphatic drainage of the abdominal wall
Superficial:
Above transumbilical line: axillary and parasternal nodes
Below transumbilical line: superficial inguinal nodes
Deep:
external iliac, common iliac and right and left lumbar nodes
What are the basic layers of the gastrointestinal wall?
Mucosa - layer of epithelial tissue on a layer of connective. three sub layers: surface epithelium, lamina proprietary and muscular layer
Submucosa
Muscularis Externa - contains a circular and longitudinal layer
Serosa or Adventitia - serosa for intra peritoneal, adventitia for retroperitoneal on walls not in contact with parietal peritoneum
Introduce the Oesophagus
L: extends from the pharynx in the mid neck and descends through the thorax on the anterior surface of the vertebral column, passing through the oesophageal hiatus to the stomach
S: is a long muscular tube with three sections, a cervical, thoracic and abdominal. with four constrictor points. The Upper oesophageal sphincters located at the level of the cricoid cartilage, the brachioaortic where the aorta and left main bronchus cross the oesophagus as well as the lower oesophageal sphincter. this is more functional as it is intrinsically a small thickening in the circular muscle layer of the wall reinforced extrinsically by the diaphragm
F: utilises peristalsis to move food bolus from the oral cavity to the stomach
Talk through the histology of the oesophagus
the oesophagus is a muscular tube with a mucous membrane.
The lumen is lined by stratified squamous epithelium (E) which changes to simple columnar epithelium at the gastroesophagel junction.
Underlying this is the lamina propria (Ly) which contains scattered lymphoid aggregates but is extremely thin.
the muscular mucosa (MM) is next. when the oesophagus does not contain bolus it lies flat and these layers are squished into deep folds.
The submucosa (SM) is made of areola connective tissue and contains seromucosa glands that aid the lubrication of the lumen.
the Muscular Externa contains muscle fibres with two main fibre directions, an inner circular (CM) layer and an outer longitudinal layer (LM) the superior 1/3 of the oesophagus contains skeletal muscle under voluntary control via the recurrent laryngeal nerve. the inferior 1/3 is smooth muscle and the middle 1/3 contains a mix of both fibres. the smooth muscle receives parasympathetic supply from the vagus nerve and sympathetic supply from the cervical sympathetic ganglion, cardiopulmonary splanchnic and abdominopelvic splanchnic fibres.
the outer most layer is the adventitia a fibrous connective tissue layer. In the abdomen the oesophagus is retroperitoneal but the stomach is intraperitoneal so the anterior surface of the muscular tube has a serous outer layer.
Discuss the neurovascular supply of the oesophagus
Arteries: inferior thyroid branch, oesophageal arteries (ventral paired br. of aorta), left gastric and left phrenic
Venous: inferior thyroid v (follows artery), oesophageal v > azygous veins, left gastric > portal vein
Lymph: paratracheal, inf. deep cervical, posterior mediastinal and left gastric nodes
Neural: intrinsic: ENS
extrinsic: para: vagus nerve
symph: cervical sympathetic ganglion, cardiopulmonary and abdominopelvic splanchnic
Introduce the stomach
L: rests in the epigastric region and some of the left hypochondriac it is the continuation of the oesophagus in the GIT and connects to the duodenum next. it is inferior to the diaphragm and anterior to the pancreas
S: J-shaped organ with three external muscular layers (longitudinal, circular and oblique) and internal surface layer contains longitudinal folds or rugae ma elf simple columnar epithelium
F: it is a temporary storage tank that also provides mechanical and chemical breakdown of bolus into chyme. it continues the peristaltic contraction of the oesophagus to churn the bolus, breaking it down and mixing it with gastric juices. This contains enzymes that breakdown certain molecules.
Identify the landmarks of the stomach
- cardia
- cardiac notch
- funds
- body
- lesser curvature
- greater curvature
- pyloric region
- pyloric antrum
- pyloric canal
- pylorus
- angular notch
Describe the peritoneal relationships of the stomach
as the stomach is intra-peritoneal there are two main folds int he lining that connect with other organs
the greater omentum: Attached to the greater curvature of the stomach and proximal duodenum, it descends to fold back and attach to the transverse colon and transverse mesocolon.
the lesser omentum:Connects the lesser curvature of the stomach and the proximal duodenum to the liver.
Explain the neurovascular supply of the stomach
A: celiac trunk > Lt/Rt gastric, short gastric & Lt/Rt gastro-omental
V: Lt/Rt gastric veins > portal vein, Short gastric & left gastro-omental > splenic v, right gastro-omental > superior mesenteric v > portal v
L: Gastric and gastro-omental nodes > celiac nodes
N: intrinsic: ENS
extrinsic: para: CNX vagus
symptoms: T6-9 greater splanchnic n through celiac plexus
visceral afferent
Discuss the histology of the stomach
The whole stomach mucosa is a tubular glandular form, thrown into rugae when contracted. It is a layer pitted with gastric pits that lead to tubular glands that produce gastric juices. there are a number of cell types in these pits, that’s secretion is stimulated by prostaglandins:
- mucosal neck cells
- parietal cells: secrete HCL which contributes to the acidity and intrinsic factor that helps with the reabsorption of vitamin B12
- chief cells: produce pepsinogen and gastric lipase, pepsinogen is converted to pepsin by HCL
- enter-endocrine cells: secrete hormones and chemical mediators: gastrin: controls secretory activity of the stomach, histamine and serotonin
muscular mucosa layer
Submucosa is relatively loose, distensable tissue, highly vascular, thin serosa layer
muscular propria: has an additional inner oblique layer to assist in the grinding and churning of bolus into chyme and mixing through the gastric juices.
Describe the histology of the gastroesophagel junction
L: gastroesophagel junction is located where the oesophagus meets the stomach inferior to the diaphragm.
S: this is a physiological sphincter rather than anatomical, there is a slight thickening in the circular muscle fibres of the muscular proprietary, that is reinforced by the diaphragm and the mucosal layer goes through a destinct change to accomodate the change in environments
F: prevents bolus from moving back through the lumen to the oesophagus
Is the space where the oesophagus meets the stomach near the lower oesophageal sphincter. It is the abrupt transition from protective squamous epithelium of the oesophagus to the tightly packed glandular secretory mucosa of the stomach. the muscular mucosa is continues but less distinctive int he stomach while the submucosa and muscular proprietary are uninterrupted
Explain the mechanisms behind gastric emptying
gastric emptying is under both hormonal and neural mechanisms.
Nervous: duodenal receptors are sensitive to distention and low pH, these stimuli cause reflex inhibition of the ENS and Vagus which reduce secretions and mobility.
duodenal hormones are also released in response to the presence of fatty, acidic chyme. these are Cholecystokinin, gastric inhibitory peptide and secretin.
Introduce the small intestines
L: the small intestines extends from the pyloric sphincter to the ileoceacal junction, inferior to the stomach an transverse colon.
S: is the extension of the GIT as a convoluted muscular tube, lined with simple columnar epithelium and subdivided into three regions. the duodenum, jejunum and the ilium. It is an intra-peritoneal organ except for the duodenum which is retroperitoneal.
F: the small intestines primarily receive secretions from the liver and pancreas that helps to chemically digest food for absorption. they mechanically breakdown chyme and using peristaltic activity to transport undigested materials to the large intestine
what are three unique features of the small intestines:
- circular folds: the muscosa and submucosa are arranged in permanent circular folds that force chyme to spiral through the lumen
- villi: are finger like projections of the mucosa with intestinal crypts between that contain 5 types of cells
- microvilli: exist on each villi that contain brush border enzymes that assist in the digestion of food.
what histological factor is different in duodenum?
the duodenum contains brunners glands in the submucosa. these release a mucous rich alkaline secretion that neutralises the acidity of the stomach chyme, increases conditions for optimal enzyme activity and lubricates the walls.
