Digestion And Absorption 💘 Flashcards
The mouth
Boundaries include hard and soft palate (roof) mylohyoid muscle (floor) cheek lips and palatoglossal fold (posterior)
Salivary glands include parotid submandibular and sublingual. Secretion is serous and or mucous
Muscle of mascitation moves mandible these include temporalis masseter medial and lateral pterygoid and Buccinator blood from maxillary artery
Tongue has intrinsic (altering shape)and extrinsic (movement) muscles and have lingual glands which secrete lipase blood mainly supplied by lingual artery
Swallowing
Soft palate pressed against back of pharynx so bolus can go down
Epiglottis tips down closing wind pipe
Peristalsis moves bolus towards stomach via oesophagus
Upper and lower oesophageal sphincter upper is made of skeletal lower made of smooth muscle and prevents reflux
Bolus now called chyme in stomach
Histology
Everything stratified squamous except stomach which is simple columnar
A lot of reflux can result in simple columnar migrating to oesophageal region
Stomach
Arterial supply from coeliac trunk and has coeliac lymph nodes
Has ridges called rugae which increase surface area
Split into cardia fundus body and pylorus
receives innervation from sympathetic (splachnic nerves)parasympathetic (medulla to gastric branches and sensory vagal fibres (gastric secretion)
Duodenum
Tube coming out of stomach surrounding pancreas has four sections superior descending (receives BD and pancreatic duct) horizontally and ascending all retroperitoneal except superior which is peritoneal
Peritoneal is fully covered with peritoneal lining retroperitoneal is only front covered
Anti lateral abdominal wall
Four muscles internal and external oblique trans versus abdominus and rectus abdominus
Functions include moves trunk supports intestines depresses ribs and increase intraabdominal pressure
Colons
Small intestine made of jejenum (thicker and less fat) and ileum
Large intestine had appendix caecum ascending transverse descending and sigmoid colon rectum and anus
Rectum has internal and external sphincters
Gastrin
Secreted by stomach in response to food especially protein
Stimulates acid and Pepsinogen secretion and gastric mobility- inhibits gastric emptying
Secretin
Secreted by S cells in duodenum in response to acid
Inhibits gastric acid production and increases pancreatic and biliary bicarbonate secretion
Cholecystokinin
Secreted by enteroendocrine cells in duodenum in response to food especially fat
Inhibits gastric secretion and mobility and stimulates pancreatic bicarbonate, enzyme and bile secretion
Specifically causes gall basset to contracts and release bile
Somatostatin
Released from d cells on stomach and duodenum in response to acid
Inhibits gastric secretion
Glycemic index
The ability of carbohydrates to increase blood glucose levels via digestion
Resistant starch
Made from remains of plant cell walls
Resistant to digestion so passes through small intestine to large intestine where it’s broken down to short chain fatty acids
Benefits include that it absorbs cholesterol bile acids and other potential carcinogens
It also increase to the viscosity of guy contents so more time for absorption
The cell types and what they make
Neck cells produce mucus
Chief cells produce proteolytic enzymes
Parietal/oxynitic cells pro deuce hcl
Gastric glands produce gastric juice
3 chemicals that drive action of parietal cells
1 inhibits
Ach and gastrin increase ca2+ influx and histamine increases adenylyl cyclase
These all increase atp pump so more h+ ions (stomach acid) into lumen
Prostaglandins- decreases adenylyl cyclase
