Block 3 Revision Questions

What constitutes the upper GI tract?

• Oesophagus

• Stomach

• Proximal duodenum

• Liver

• Gall bladder

• Pancreas

What is the junction between the foregut and the midgut?

Major duodenal papilla

What are the three main branches of the descending aorta that supply the GI tract?

• Celiac trunk - foregut

• Superior mesenteric artery - midgut

• Inferior mesenteric artery - hindgut

What are the two cavities of the mouth?

• Vestibule

• Oral cavity

What structure separates the oral cavity and the oropharynx?

Palatoglossal fold

What muscle forms the floor of the oral cavity?

Mylohyoid muscle

What nerve innervates the mylohyoid muscle?

Mandibular nerve (V3), branch of the trigeminal

What is the function of the mylohyoid?

• Depress the mandible to open the mouth

• Pulls forward the pharynx during swallowing

What are the three salivary glands of the oral cavity?

• Parotid gland

• Submandibular gland

• Sublingual gland

What nerve innervates the intrinsic muscles of the tongue?

Hypoglossal (XII)

Which muscles of mastication elevate the mandible?

• Temporalis

• Masseter

• Medial pterygoid

What are the muscles involved in mastication?

• Temporalis

• Zygomatic arch

• Masseter (deep)

• Masseter (superficial)

• Parotid duct

• Buccinator

Which nerve supplies sensation to the tongue and gums?

Lingual nerve

Where are the palatine tonsils?

Between the anterior and posterior palatoglossal folds

Which of the oesophageal sphincters is under voluntary control?

Upper - skeletal muscle

What is the principle function of the lower oesophageal sphincter?

Prevents gastro-oesophageal reflux

At which three points is the oesophagus constricted?

• Pharangeal-oesophageal junction

• Tracheal bifurcation

• Gastro-oesophageal junction

Where in the GI tract is stratified squamous epithelium found?

• Mouth

• Oropharynx

• Laryngopharynx

• Oesophagus

What type of epithelium is found in the stomach?

Simple columnar

What are the nine abdominal regions?

• Right hypochondriac

• Epigastric

• Left hypochondriac

• Right lumbar

• Umbilical

• Left lumbar

• Right iliac

• Hypogastric

• Left iliac

What is the main arterial supply of the oesophagus?

Oesophageal arteries

What are the four regions of the stomach?

• Cardia

• Fundus

• Body

• Pyloric

What are the three phases of swallowing?

• Voluntary

• Pharangeal

• Oesophageal

What is peristalsis?

Contraction and relaxation of muscles in oesophagus

Produces wave down tube

Moves food down

Where is nausea regulated?

Medulla

• Vomiting centre

• Chemoreceptor trigger zone

What do chief cells secrete?

• Pepsinogen

• Gastric lipase

What is the physiology of gastric acid secretion?

• Carbonic anhydrase catalyses formation of carbonic acid

• This dissociates to give H⁺

• Proton pump in parietal cell transports H⁺ into lumen and K⁺ into cell to balance out charge

• Cl^- diffuses out into lumen alongside K⁺ to balance the charge

• H⁺ and Cl^- combine to form HCl

What effect does gastrin have?

Stimulate secretion of gastric acid and pepsinogen

What chemicals inhibit gastric acid secretion?

• Somatostatin

• CCK (cholecystokinin)

Where are Peyer’s patches (clusters of lymphatic tissue) found?

Ileum

Where are Brunner’s glands (secrete alkaline mucus) found?

Duodenum (neutralise stomach acid)

In what form can the small intestine absorb sugars?

Monosaccharides

How are monosaccharides absorbed?

Facilitated diffusion or active transport

Which co-transporter enters mucosal cells with glucose?

2Na⁺

Which transporter allows the entry of glucose into capillaries from mucosal cells?

GLUT2

How are most peptides absorbed?

As amino acids via active transport

How are lipids absorbed?

• Broken down into fatty acids

• Surrounded by bile salts to form micelles

• Move from lumen to brush border, fatty acids diffuse into absorptive cells

• Recombine to form triglycerides

• Aggregate with phospholipids & cholesterol, coated with proteins to become chylomicrons

• Exocytosed into lacteals, travel through lymphatics, enter blood at left subclavian vein

• Removed from blood at liver and adipose tissue by lipoprotein lipase

Where are most bile salts reabsorbed?

Ileum

What constitutes the midgut?

• Distal duodenum

• Jejenum

• Ileum

• Ascending colon

• Proximal 2/5 transverse colon

What are the four parts of the duodenum?

• Superior

• Descending

• Inferior

• Ascending

Is this the jejunum or ileum?

Jejunum

• Long vasa recta (straight arteries)

• Small arterial arcades (arterial loops)

What is the blood supply of the jejunum?

Jejunal arteries

Originate from superior mesenteric

What are the projections of the ileum into the large intestine called?

Ileocecal folds

What are three identifying features of the large bowel?

• Omental appendices (fat filled pouches of peitoneum attached externally)

• Taeniae coli (three longitudinal bands of smooth muscle)

• Haustra (sacculations created by semilunar folds on internal surface)

Is the colon peritoneal or retroperitoneal?

Retroperitoneal

At what level is the rectosigmoid junction?

Third sacral vertebra

What are the two types of smooth muscle in the muscalaris of the small intestine?

• Outer - thin, longitudinal fibres

• Inner - thick, circular fibres

What type of epithelial cells line the large intestine?

Simple columnar

What is the innervation of the GI tract?

Enteric nervous system

What are the three flat muscles of the anterior abdominal wall?

• External oblique

• Internal oblique

• Transversus abdominus