From Plate To Bowl Flashcards
Name the four main layers/tunics of the gut wall?
- mucosa.
- submucosa.
- muscularis externa.
- series or adventitia.
Name the components that compromise the mucosa?
- epithelium.
- lamina propria.
- muscularis mucosa.
What are the components of the muscularis externa in a basic plan of the gut?
- inner circular layer.
- outer longitudinal layer.
Where in the digestive tract is the muscularis mucosa composed of skeletal muscle (under somatic control)?
Pharynx, upper third of esophagus, external anal sphincter.
What are the two nerve plexuses that form the enteric nervous system of the gut and state where it is located.
- submucosal (Meissner’s) plexus: in the submusosa.
- myenteric (Auerbach’a) plexus: in the muscularis between the muscle layers.
Greater omentum.
Connects transverse colon and greater curvature of the stomach.
Lesser omentum.
Connects stomach and duodenum to liver.
Falciform ligament.
Connects liver to anterior abdominal wall.
Mesentery.
Connects small intestine to posterior abdominal wall.
Mesocolon.
Connects large intestine to posterior abdominal wall.
What is peritonitis?
Inflammation of the peritoneum.
Which adult organs arise from the foregut/coeliac trunk?
Pharynx, oesophagus, stomach, 1st part of duodenum, liver and biliary ducts, pancreas, (spleen).
Which adult organs arise from the midgut/superior mesenteric?
Remainder of small intestine, cecum, appendix, ascending colon, right 2/3 transverse colon.
Which adult organs arise from the hindgut/inferior mesenteric?
Remainder of the colon.
What are the muscles of mastication?
- masseter.
- temporalis.
- pterygoids medial.
- pterygoids lateral.
Function of the masseter muscle?
Elevates and protracts mandible.
Function of the temporalis muscle?
Elevates and retracts mandible.
Function of the pterygoids medial muscle?
Elevates and protracts mandible.
Functions of the pterygoids lateral?
Depressed and protracts mandible.
What type of epithelium is found on the surface of the tongue? Why?
Stratified squamous, keratinised in parts (on the filiform papillae) permits wear and tear.
The tongue is a muscular structure; explain the difference between intrinsic and extrinsic muscles of the tongue?
- intrinsic lie entirely within tongue.
- extrinsic have attachments to bones of skull.
What type of papilla are the only ones that do not have tastebuds?
Filiform.
What are the four types of papilla?
- (circum) vallate.
- fungiform.
- foliate.
- filiform.
What is the difference in the composition of the secretions produced by serous and mucus cells?
- serous: water and amylase.
- mucus: mucin, water.
What type of secretion does the parotid gland have?
Serous.
What type of secretion does the submandibular gland have?
Mixed, primarily serous.
What type of secretion does the sublingual gland have?
Mixed, primarily mucous.
What are the upper and lower boundaries of the nasopharynx?
- upper boundary: choanae.
- lower boundary: soft palate.
- pseudostratified ciliated columnar with goblet cells.
What are the upper and lower boundaries of the oropharynx?
- upper boundary: soft palate.
- lower boundary: epiglottis.
- non keratinised (moist) stratified squamous.
What are the upper and lower boundaries of the laryngopharynx?
- upper boundary: tip of epiglottis.
- lower boundary: oesophagus.
- non keratinised (moist) stratified squamous.
What type of muscle is found in the posterior walls of the pharynx? Why is this?
Skeletal, for voluntary control of food bolus.
What type of tissue is the epiglottis made from?
Elastic cartilage.
There are numerous glands in the submucosa (may not be visible). What are their secretions made of and what purpose do they serve?
Mucus, for lubricating passage of food.
What type of muscle makes up the upper 1/3 of the oesophagus?
Skeletal muscle.
What type of muscle makes up the middle 1/3 of the oesophagus?
Skeletal and smooth muscle.
What type of muscle makes up the lower 1/3 of the oesophagus?
Smooth muscle.
The outermost layer of the thoracic oesophagus consists of connective tissue that anchors it to surrounding structures (there is no serous membrane present). What is this layer called?
Adventitia.
What volume can the stomach hold?
Between 50ml when empty to 3.5 to 4 when full.
What role do the sphincters of the stomach play?
Isolate acidic stomach environment from oesophagus and duodenum, regulate flow.
What type of the epithelium is found here?
Simple columnar.
What do mucous neck cells secrete?
Mucus.
What do parietal cells secrete?
HCL.
What do chief cells secrete?
Pepsinogen.
What products do entero-endocrine cells (G cells) secrete?
Gastrin.
Where do gastrin secretions pass through?
The lamina propria into the blood, rather than going into the lumen of the stomach.
What role do the secretions from G cells play in the digestive process?
Stimulates gastric activity.
How long is the jejenum and the ileum?
- jejenum: ~2.5m long.
- ileum: ~3.5m long.
What macroscopic structures, found within the wall of the small intestine, increase its surface area?
Plicae circulares.
What function do the plicae circulares have?
Help to spiral chyme along length of intestine.
What gives the internal surface of the small intestine a velvety appearance?
Villi.
Are there goblet cells in the duodenum?
Yes.
The intestinal glands (crypts of Lieberkuhn) secrete intestinal juice; what does it contain?
Serous fluid and enzymes from the intestinal mucosal cells.
What is the function of the duodenal (Brunner’s) glands in the submucosa?
Secrete alkaline mucus to neutralise gastric acid in chyme (not in the jejenum and ileum- no longer an acidic environment).
What types of motility are found in the small intestine?
Peristalsis and segmentation.
What is the gastro-ileal reflex?
Food/activity in the stomach encourages material in the ileum to move on to the large intestine.
What are the three external macroscopic features are associated with the large intestine?
- taenia coli.
- haustra.
- omental (epicolic) appendages.
Name three main functions of the large intestine.
- absorption of remaining water and electrolytes.
- bacterial production of vitamins.
- formation and elimination of faeces.
Does the small intestine or large intestine absorb the greater volume of water?
Small intestine.
Name four functions of the large intestine.
- breakdown of amino acids.
- decompose bilirubin.
- produce vitamin B and K.
- indigestible CHOs.
