Download Anatomy and Function of the Digestive System: Terms, Definitions, and Structures and more Quizzes Physiology in PDF only on Docsity!
Digestion
-process where food is changed into a form that can be absorbed -breakdown of digested food -absorption on nutrients into blood TERM 2
Metabolism
DEFINITION 2 -production of ATP -anabolic & catabolic cellular activities TERM 3
Digestive system
DEFINITION 3 -organs that promote digestion & absorb the products - alimentary canal: one continuous tube; mouth->pharynx -
esophagus->stomach->intestines->rectum->anus - accessory organs: salivary glands, liver, gallbladder, pancreas TERM 4
Functions of digestive system
DEFINITION 4 -ingestion: getting food into mouth -propulsion: moving food - mechanical digestion: squashing, churning, turning; NOT ONLY IN MOUTH -chemical digestion: enzymes breakdown food molecules into building blocks in pancreas & stomach; each food group uses different enzymes -absorption: end products absorbed into intestinal fluid than blood -defecation: elimination of indigestible substances -compaction: compression & dehydration of indigestible materials TERM 5
Alimentary canal structures
DEFINITION 5 -4 layers; mucosa, submucosa, muscularis externa, serosa
mucosa layer
-inner most layer -has 3 layers: mucosal epithelium, lamina propria (blood vessels, sensory nerves, lymph), muscularis mucosa (smooth muscles & elastic fibers; circular & longitudinal layers) -may have folds in increase surface area -may have glands secreting mucous & digestive enzymes - protects, absorbs & secretes TERM 7
sub mucosa
layer
DEFINITION 7 -dense irregular CT, glands, blood vessels, lymph vessels & nerves -nourishes surrounding tissues -carries away absorbed materials TERM 8
muscularis externa
DEFINITION 8 -2 layers of smooth muscle -inner: circular fibers; decrease diameter when contract -outer: longitudinal: shorten tube when contract TERM 9
serosa
DEFINITION 9 -outer layer -epithelium & CT -protects & secretes serious fluid -does not exist above the diaphragm -also called adventitia TERM 10
Motor Functions of the Alimentary
Canal
DEFINITION 10 -autorythmic -segmentation: mixing, churning & sloshing movements; mostly circular muscle contractions; mixes food with digestive juices; occurs every 20 sec, when empty it is your stomach growling; no net movement in any particular direction; goal is to fragment bolus -peristalsis: wave-like patterns of propulsion by coordinated muscle movements (circular contract first preventing bolus from going backwards, then longitudinal advancing it down the tract); -stimulus: expansion of tube due to accumulation of food
Parts of teeth
-crown: covered by enamel; enamel: hardest substance in body - root: base within host bone -neck: boundary between root & crown -gingiva: gums; gingival sulcus: where gum & tooth meet -dentin: inner mineral matrix -cementum: bone-like material covering root - periodontal ligament: helps anchor tooth -pulp cavity: BV's, nerves, & spongey CT; spongy area -apical foramen: opening into tip of root -root canal: contains BV's & nerves; where nerves & blood exit TERM 17
Dental Succession
DEFINITION 17 -primary/deciduous teeth: between 6 months & 4 years old; 20 total, incisors, cuspids, 1st & 2nd molars - secondary/permanent teeth: 32 total, incisors, cuspids, 1st & 2nd bicuspids, 1st, 2nd, & 3rd molars TERM 18
Movement through pharynx
DEFINITION 18 -enabled by swallowing -bolus enter oropharynx -passes the laryngopharynx TERM 19
Swallowing mechanism
DEFINITION 19 -deglutition -buccal phase: voluntary phase, compresses bolus against hard palate, elevates soft palate, tongue retracts -pharyngeal phase: bolus touches posterior pharyngeal wall, epiglottis tips backward, bolus enters esophagus -esophageal phase: upper esophageal sphincter opens, peristalsis begins, lower esophageal sphincter opens TERM 20
esophagus
DEFINITION 20 -passage for food only -straight collapsable tube -penetrates diaphragm through esophageal hiatus -mucosa: stratified squamous, has large folds (giving it the ability to expand) - muscularis: skeletal muscle in superior regions, as you move down it becomes smooth -adventicia: so serous, CT that helps to anchor
stomach functions
-upper left part of abdominal cavity, under the diaphragm - storage -mechanical breakdown of food continues -chemical breakdown of protein begins -delivers chyme to small intestine -little absorption: alcohol, water, aspirin TERM 22
Stomach parts/ regions
DEFINITION 22 -lesser curvature: medial surface -greater curvature: lateral surface -cardiac region: near esophageal opening, where sphincter is -fundus: up over cardiac region; temporary storage area; may fill with air -body region: largest part - pylorus: narrow, inferior end; pyloric sphincter: muscle that acts as a valve to prevent regurgitation TERM 23
Stomach Histology
DEFINITION 23 -mucosa: folded into rugae for expansion during a full stomach -muscularis: longitudinal (outer), circular (middle), oblique (inner) TERM 24
Gastric secretory
cells
DEFINITION 24 -parietal cells: secrete HCl & intrinsic factors; lower pH/ absorbs B12 -chief cells: secrete pepsinogen, pepsin when exposed to HCl, rennin & gastric lipase; breaks down proteins -enteroendocrine cells: secrete gastrin TERM 25
small intestine functions
DEFINITION 25 -major digestive organ, 18-20 feet -completes digestion of chyme -receives secretions from pancreas & liver -absorbs products of digestion; plicate circulates (folds on inner lining), intestinal villi (finger-like projections of mucosa), microvilli (finger-like extensions of cells membranes) - transports remaining residue to large intestine
Gall bladder
-on inferior surface of liver; connected to cystic duct that joins hepatic duct -stores bile, concentrates bile by reabsorbing water, release bile into duodenum -common bile duct: hepatic & cystic; goes to duodenum TERM 32
Path of Bile
DEFINITION 32 -hepatocytes in liver produce bile -go to bile ducts->hepatic ducts->common hepatic duct-> can be directly release to the common bile duct or stored in cystic ducts -from common bile ducts->hepatopancreatic sphincter->duodenum -from system ducts either goes to gallbladder or the common bile ducts->hepatopancreatic sphincter->duodenum TERM 33
Pancreas
DEFINITION 33 -structure: head, body, tail -pancreatic juice goes to duodenum via the pancreatic duct or hepatopancreatic sphincter -pancreatic juice: produced by pancreatic stimuli, composed of pancreatic amylase (finish digesting starch), proteinase & trypsin (digests proteins), lipase (digests fat), nuclease (digests nucleic acids), alkaline (neutralizes acidic chyme)
