GI Tract Flashcards
The peritoneal cavity lies between what two layers of tissue?
Visceral and parietal peritoneum
The lesser omentum connects what two structures?
Stomach and liver
The greater omentum drapes over which structures and where is it attached?
Transverse colon, jejunum and ileum. Attaches to the greater curvature of the stomach and the posterior abdominal wall.
Omentum means what in Latin?
Apron
What are the two sections of the peritoneal cavity?
Greater sac and omental bursa
What double-fold of peritoneum connects the intestines to the posterior abdominal wall?
Mesentery
The transumbilical plane usually lies at around what vertebral level?
L3/L4, but can vary
The median plane lies between what two structures?
Xiphoid process and pubic symphysis
Point and name the 9 regions of the abdomen
Right hypochondrium, epigastric, left hypochondrium, left flank, umbilical, right flank, right groin, pubic, left groin
Describe the position of the transpyloric plane and why it is important
Horizontal plane half way between the jugular notch and pubic symphysis
Pylorus, pancreatic neck, colic flexures, origin of superior mesenteric artery and hepatic portal vein.
The bifurcation of the abdominal aorta occurs on what plane?
Supracristal plane (L4/5)
What are the two layers of superficial fascia in the abdomen?
Camper’s fascia and Scarpa’s fascia
What layer of fascia extends into the perineum and labia majora/penis and scrotum?
Scarpa’s fascia
What three muscle layers would you find in the lateral abdomen?
External oblique, internal oblique and transversus abdominis
What are the two deep layers of the abdominal fascia?
Transversalis and extraperitoneal fascia
What is the aponeurosis of the oblique muscles called?
Rectus sheath
Which part of the abdomen will you find the linea alba is created by an anterior AND posterior rectus sheath?
Upper 3/4
What is the linea alba?
Fibrous midline structure between the two rectus abdominis muscles, formed by the aponeurosis of the obliques (rectus sheath)
The inguinal ligament is continuous with what structure of the abdomen?
Aponeurosis of the external oblique
The quadratus lumborum and psoas major are separated from the paraspinal muscles by what layer of tissue?
Thoracolumbar fascia
The abdominal muscles are all supplied by the anterior rami of which spinal nerves?
T7-T12
The superior epigastric and subcostal arteries originate from which artery?
Subclavian
The femoral artery gives off what two branches to the abdomen?
Superficial epigastric and superficial circumflex ileac arteries
The inferior epigastric and deep circumflex ileac originate from which artery?
External ileac
Venous drainage from the abdomen ultimately drains into which two main veins?
Femoral or axillary veins
What skin and muscles are the only ones to be supplied by the posterior rami of spinal nerves?
Skin and deep muscles of the back
What dermatome lies roughly over the umbilicus?
T10
Which layer of the peritoneum will have well-localised pain and why?
Parietal layer because it is supplied by somatic fibres from spinal nerves
What nerves from the lumbar plexus supply the abdominal muscles?
Subcostal (T12), Iliohypogastric (L1), Ilioinguinal (L2), Genitofemoral (L1/2)
What type of incision is typically used for an open appendectomy?
Gridiron
What type of incision is typically used for an c-section?
Pfannenstiel
What type of incision is typically used for an open cholecystectomy?
Kocher’s
Which nerves may be damaged in surgical incisions, causing muscle weakness that can lead to a direct inguinal hernia?
Ileoinguinal and ileohypogastric nerves
Which type of hernia is more common?
Indirect hernia
Briefly describe the difference between an indirect and direct inguinal hernia
Indirect hernia protrude through the inguinal rings, lateral to the inferior epigastric vessels.
Direct hernias protrude through weaknesses in the abdominal wall at the conjoint tendon (medial to the inferior epigastric vessels)
What is the conjoint tendon?
The combined insertion of the transversus abdominis and internal oblique into the pubis
The superior surface of the tongue is covered in four types of lingual papillae, what are these called, what is their function and what innervates them?
Filiform papillae, general sensation, lingual branch of mandibular division of trigeminal (CN V3)
Fungiform and foliate papillae, taste buds, chorda tympani branch of facial nerve (CN VII)
Vallate papillae, larger taste buds (anterior to terminal sulcus), glossopharyngeal nerve (CN IX)
What nerve innervates the palatoglossus muscle?
Vagus (CN X)
What are sialolithiasis and what structure are they most associated with?
Calculi most common in the submandibular gland and duct.
Which phase of deglutition is voluntary?
Oral phase
What muscle relaxes to allow food into the oesophagus?
Cricopharyngeus
The elevation of the soft palate and closing of the epiglottis happen during which phase of deglutition?
Pharyngeal
What motion pushes the bolus of food down through the oesophagus?
Peristalsis
The oesophagus is divided into what three sections?
Cervical (C6-T1), thoracic (T1-10) and abdominal (T10-11).
The oesophageal hiatus is at what spinal level?
T10
The oesophageal arteries branch off what main artery?
Thoracic aorta
Describe the general innervation of the oesophagus
Parasympathetic- vagus (CN X)
Sympathetic- T6-9
Describe the general regions of the stomach
Cardia, fundus, body, pyloric antrum/canal/orifice.
The stomach receives blood supply from which branch of the abdominal aorta?
Coeliac trunk
Describe the lymph drainage from the stomach and the clinical importance of supraclavicular lymphadenopathy
Coeliac nodes -> cisterna chyli -> thoracic duct.
Virchow’s node- an enlarged left supraclavicular node, close to where the thoracic duct enters the systemic circulation. Can be a sign of metastatic gastric cancer.
Describe the venous drainage from the stomach
Splenic and superior mesenteric veins -> hepatic portal vein
What planes separate the nine regions of the abdomen?
Two midclavicular vertical planes. Two horizontal: subcostal and intertubercular planes.
Where is McBurney’s point?
1/3 of the way between the right ASIS and the umbilicus
Describe the layers of tissue in the abdomen, lateral to the rectus abdominis.
Skin, Camper’s fascia, Scarpa’s fascia, muscles/aponeurosis (rectus sheath), transversalis fascia, extraperitoneal fascia, parietal peritoneum
The superior epigastric artery is a branch of what artery?
Internal thoracic
The inferior epigastric artery is a branch of what artery?
External ileac
The duodenum curves around the head of which organ?
Pancreas
The oesophagus is lined with what type of epithelium?
Non-keratinising stratified squamous
The stomach is lined with what type of epithelium?
Simple columnar
What enzyme is important in liberating B12 from proteins?
Pepsinogen
What molecule helps with bicarbonate secretion, blood flow and cell membrane integrity in the stomach? What drug class can disrupt these processes?
Prostaglandins, NSAIDs
What is the function of bile?
Help absorb fat
H.Pylori will turn what colour under gram staining?
Red (negative)
Urea is a waste product of what process?
Protein lysis
How does H.Pylori affect the stomach lining?
Reduces thickness of mucosal layer, produces cytotoxins that weakness cellular junction and alters pH gradients.
What protects B12 from destruction by HCl in the stomach?
R protein released in saliva, binds to B12 and protects it
People with pernicious anaemia produce autoantibodies against what?
Intrinsic factor and parietal cells. Resulting in poor B12 absorption.
What are parietal cells?
Cells in the stomach lining that secrete HCl and intrinsic factor
What cells exist in the GI tract to lubricate the faecal material?
Goblet cells
What are enterocytes and what main structures in the GI tract do they line?
Columnar epithelial cells, specialised for absorption.
Small and large intestine
Draw the main branches of the arterial supply of the stomach
https://i.pinimg.com/originals/d5/a8/41/d5a8410c6619abaa2dd8d154d74461e0.png
What does the myenteric plexus mainly control?
Gastro-intestinal movements