Chapter 25 - Digestive System Flashcards
What is digestion?
Process whereby food is changed into a form that can be absorbed, breakdown of ingested food, and absorption of nutrients into blood.
What is metabolism?
Production of ATP and anabolic & catabolic cellular activities.
What are the 2 parts of the digestive system?
Alimentary canal and accessory glands.
What makes up the alimentary canal?
Mouth, pharynx, esophagus, stomach, intestines, rectum, and anus.
What are the accessory glands?
Salivary glands, liver, gallbladder, and pancreas.
What are the layers of the digestive wall?
INSIDE TO OUTSIDE
Mucosa, submucosa, muscularis, and serosa.
What are the 3 layers of the mucosa?
Mucosal epithelium, lamina propria, and muscularis mucosa.
What does the lamina propria contain?
BVs, sensory nerves, lymph vessels, and MALT.
What does the mucosa muscularis contain?
Smooth muscle and elastic fibers.
What are the layers of the muscularis?
Circular and longitudinal.
Can the mucosa have folds?
YES!!!!
What do folds do?
Increase surface area.
What glands can be in the mucosa?
Mucous and digestive enzymes.
What are the functions or the mucosa?
Protection, absorption, and secretion.
What does the submucosa contain?
Loose CT, glands, BVs, lymph vessels and nerves.
What are the functions of the submucosa?
Nourish surrounding tissues and carry away absorbed materials.
What are the layers of the muscularis?
Inner and outer.
What is the inner layer?
Circular smooth muscle.
What is the outer layer?
longitudinal smooth muscle.
What is the function of the circular smooth muscle?
Decrease the diameter when contracted.
What is the function of the longitudinal muscle?
Shorten tube when contracted.
What is another name for the serosa?
Visceral peritoneum.
Does the serosa exist superior to the diaphragm?
NEGATIVE!!
What replaces the serosa above the diaphragm?
Adventitia.
What is the function of the serosa?
Protection and secrete serous fluid.
What is the peritoneum?
A series of membranes in the abdominal cavity.
What are the layers?
Visceral peritoneum and parietal peritoneum.
What does the visceral peritoneum adhere to?
Directly to the internal organs.
What does the parietal peritoneum adhere to?
The abdominal wall.
What is between the layers?
Peritoneal cavity.
Are the layers continuous?
YES’M.
What are mesentaries?
Sheets of peritoneum connected to organs.
What are the functions of mesentaries?
Access route for vessels and nerves and stabilize position.
What are the mesentaries of the peritoneum?
Lesser omentum and greater omentum.
What does the lesser omentum connect?
Stomach to liver.
Greater omentum characteristics?
Starts at stomach, descends inferior, the ascends to form a pouch and attaches to colon.
What is the pouch filled with?
Adipose.
What is mesentery proper?
Attaches to the majority of the small intestine.
What is the mesocolon?
Attaches to large intestine.
What do the mesentery proper and mesocolon allow?
Allow for nerves, BVS, and lymphatics to connect to intestines.
What is peristalsis?
Propels bolus down the tract.
What is a bolus?
Swallowed food.
What muscles contract first in peristalsis?
Circular muscles prevent bolus from moving back.
What do longitudinal muscle do?
Advances it down the tract.
What is segmentation?
No net movement in any particular direction, goal is to fragment bolus, and mostly circular muscle contractions.
What are the functions of the mouth?
Mastication/mixing, lubrication, speech, taste/evaluation, and limited digestion.
Components of the mouth?
Hard and soft palate.
What is the hard palate?
Palatine bone on roof of mouth.
What is the soft palate?
CT extension of the palate and uvula.
Uvula position?
Dangles at the end of the soft palate.
Functions of the uvula?
Prevents food from going down prematurely.
What are the salivary glands?
Parotid, submandibular, and sublingual.
What are the functions of salivary glands?
Produce saliva, form food bolus, make salivary amylase, and dissolve chemicals for taste.
What is saliva made of?
Mucous and serous fluid.
What does salivary amylase breakdown?
Starch.
What are the functions of teeth?
Mastication.
What are the different types of teeth? (4)
Incisors (cutting), cuspids/canines (tearing), bicuspids/premolars (crushing&grinding), and molars (crushing&grinding).
What are the 4 regions of the tooth?
Crown, root, neck, and gingiva.
What is the crown?
Exposed region of the tooth and covered in enamel.
What is the root?
Base and within host bone.
What is the neck?
Boundary between root and crown.
What is the gingiva?
The gums and gingival sulcus (where gums and tooth meet).
What are the 2 sets of teeth you get throughout life?
Primary or deciduous and secondary or permanent.
Primary teeth number and type?
20 total and incisors, cuspids, and 1st & 2nd molars.
Secondary teeth number and type?
32 total and incisors, cuspids, 1st & 2nd bicuspid, and 1st, 2nd, & 3rd molars.
Movement through the pharynx is enabled by what?
Swallowing.
What path does bolus take through pharynx?
Oropharynx to laryngopharynx.
What is swallowing also known as?
Deglutition
What are the 3 stages of swallowing?
Buccal phase, pharyngeal phase, and esophageal phase.
What is the function of the esophagus?
Passageway for food to only the stomach.
Characteristics of the esophagus?
Straight, collapsible tube, and penetrates diaphragm through esophageal hiatus.
What are the 3 layers of the esophagus?
Mucosa, muscularis, and adventitia.
Mucosa characteristics of esophagus?
Stratifeid squamous and large folds.
muscularis characteristics of esophagus?
Skeletal muscle in superior regions.
What are the functions of the stomach?
Storage, mechanical breakdown, chemical breakdown or protein, delivers chyme to small intestine, little absorption of nutrients.
What nutrients are absorbed?
Alcohol, aspirin, and water.
What is the general shape of the stomach?
Lesser curvature and greater curvature.
What are the 4 major regions of the stomach?
Cardia, fundus, body, pyloris.
Layers of the stomach?
Mucosa and muscularis.
Mucosa characteristics of stomach?
Folded into rugae for expansion during a full stomach.
What are the 3 muscle layers of the muscularis?
Outer=longitudinal
Middle=circular
Inner=oblique
What do gastric glands do?
Make gastric juice.
What are the 3 secretory cell types?
Parietal cells, chief cells, and enteroendocrine cells.
Parietal cells secrete what?
HCL (lowers pH) and intrinsic factor (absorbs B12).
Chief cells secrete what?
Pepsinogen (breaks down proteins).
Enteroendocrine cells secrete what?
The hormone gastrin.
What is the major digestive organ?
smaLL intestiNE.
What are the 3 regions of the small intestine?
Duodenum, jejunum, and ileum.
Duodenum characteristics?
25cm, and digestive secretions from liver and pancreas.
Jejunum characteristics?
2500cm and most digestion and absorption.
Ileum characteristics?
3500cm.
What are the functions of the small intestine?
Completes digestion of chyme, receives secretions from pancreas & liver, absorbs products of digestion, and transport remaining residue to large intestine.
What is responsible for the majority of absorption?
Small intestine.
How does the small intestine increase surface area?
Plicae circulares, intstinal villi, and microvilli.
What are plicae circulares?
Folds in lining.
What are intestinal villi?
Finger like projections of mucosa.
What are microvilli?
Finger like extensions of cell membranes.
What are the functions of the large intestine?
No digestive enzymes, no nutrient absorption, and bacteria here digest remaining nutrients.
What are absorbed in the large intestine?
Remaining water and vitamins K & B.
What happens to remaining material and how?
Defecated as feces, slow, infrequent peristalsis, and enabled by mucus production.
What are the 8 regions of the large intestine?
Cecum, veriform appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anus.
Cecum characteristics?
Dilated, pouch like structure.
Veriform appendix characteristics?
Narrow tube with closed end, hangs down from cecum, and lymphatic tissue but no digestive function.
Ascending colon characteristics?
Travels upward along posterior wall to just below liver.
Transverse colon characteristics?
Turns at right colic flexure and goes toward spleen.
Descending colon characteristics?
Turns downward at left colic flexure.
Sigmoid colon characteristics?
S-shaped part near terminal end.
Rectum characteristics?
Follows curvature of sacrum and leads to anal canal.
Anus characteristics?
Opening to outside, guarded by 2 sphincters.
What are the 2 sphincters?
Internal (smooth muscle) and external (skeletal muscle).
What are the functions of the liver?
Carbohydrate and lipid metabolism, protein metabolism, storage, blood filtering, detoxification, and secretes bile.
What does the liver store?
glycogen, vitamins, and iron.
What is protein metabolism in the liver?
Making blood proteins.
What is the function of carbohydrate and lipid metabolism in the liver?
Synthesizes lipoproteins, phosolipids & cholesterol and converts carbohydrates & proteins to fat.
What are the structures of the liver?
Divided into lobes by falciform ligament, coronary ligament attaches liver to diaphragm, largest lobe on right, and hepatic lobules.
What is the hepatic lobule?
The functional unit.
What 3 things does the hepatic lobule contain?
Hepatocytes, hepatic sinusoids, and kupffer cells.
Where are the hepatocytes?
Around the central vein.
What do hepatocytes do?
Remove toxins and produce bile.
What are the hepatic sinusoids?
Vascular channels.
What do hepatic sinusoids do?
Receive blood from portal veins.
What are kupffer cells?
Fixed macrophages.
Where is the gallbladder located?
On the inferior surface of the liver.
What are the functions of the gallbladder?
Store bile, concentrate bile by reabsorbing water, and release bile into duodenum.
What paths does bile take?
From left and right hepatic duct to common hepatic duct to common bile duct to duodenum or left and right hepatic duct to common hepatic duct to cystic duct to gallbladder back to cystic duct to common bile duct to duodenum.
What is the structure of the pancreas?
Head, body, and tail.
How does pancreatic juice enter the duodenum?
Pancreatic duct and hepatopancreatic sphincter.
What is pancreatic juice produced by?
Pancreatic acini.
What is pancreatic juice composed of?
Pancreatic amylase, proteinases & trypsin, lipase, nucleases, and alkalines.
Pancreatic amylase breaks down?
Strach.
Proteinases & trypsin break down?
Protein.
Lipase breaks down?
Fat.
Nucleases break down?
Nucleic acids.
Alkaline do what?
neutralizes acidic chyme.
YOU ARE DONE CONGRATS!!!!!
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