Chapter 25 Flashcards
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Mechanical and chemical breakdown of food into a form usable by the body?
Digestion
The selective intake of food?
Ingestion
Uptake of nutrient molecules into cells?
Absorption
Absorbing water and consolidating the residue into feces?
Compaction
Elimination of feces?
Defecation
The digestive tract has two anatomical subdivisions what are they?
Digestive tract and accessory organs
The muscular tube extending from mouth to anus?
Digestive tract
The teeth, tongue, salivary glands, liver, gallbladder, etc.?
Accessory organs
There are four tissue layers what are they?
Mucosa
Submucosa
Muscularis externa
Serosa (visceral peritoneum)
Lining of the digestive tract that secrete and absorbs?
Mucosa
Stratified squamous or simple Columnar?
Epithelium
Loose connective tissue layer?/
Lamina propria
Smooth muscles That tense the mucosa?
Muscularis mucosae
Thick layer of loose connective tissue containing blood vessels, lymph vessels, glands?
Submucosa
Nerve fibers that control movement of the muscularis mucosa and glands?
Submucosal plexus
Muscles the contract to propel residue through the digestive tract?
Muscularis externa
There are two types of muscularis externa what are they?
Circular muscle and longitudinal muscle
Myenteric plexus which is nerve fibers the control peristalsis
Thin layer of areola tissue and simple squamous?
Serosa or (visceral peritoneum)
The peritoneum
Covers the external surfaces of most digestive organs?
Visceral peritoneum
Serous membrane that lines the abdominal cavity?
Parietal peritoneum
Connective tissue that loosely suspends the organs from the body?
Mesenteries
Two layered membrane extending from the body wall to digestive organs, then separates and passes around organs forming serosa?
Posterior mesentery
Mesentery from the liver to the stomach?
Lesser omentum
Mesentery that hangs from the stomach and loosely covers the small intestine?
The greater omentum
Mesentery that anchors the colon to the posterior abdominal wall?
Mesocolon
What are the six structures of the mouth?
Cheeks and lips Tongue Palate Teeth Saliva Extrinsic salivary glands
Anatomy of the digestive system (Gastrointestinal or G.I. tract)
Ingestion of food, taste, chewing, speech, etc.?
Mouth
Retains food, articulate speech, suck and blow?
Cheeks and lips
Manipulates and tastes food?
The site of taste buds?
The median fold attaching the tongue to mouth?
Tongue
Lingual papillae
Lingual frenulum
Separates oral and nasal cavity?
Palate
What aids the tongue in holding and manipulating food?
The Palatine rugae
Projection of soft palate that helps retain food in mouth is called what?
The uvula
These help masticate or chew food?
Teeth or dentition
This is a pit or socket each tooth is embedded in?
Alveolus
Anchors the tooth in the alveolus?
Periodontal ligament
Tissue that covers the alveolar bone?
Gingiva or gum
The portion of tooth above the gum?
The crown
The portion of tooth below the gum?
The root
Bacteria in the mouth secrete acids and enzymes to digest components of teeth forming holes?
Dental caries (cavities) - brushing prevents
Gum inflammation calculus between Tooth and gum?
Gingivitis- flossing prevents this
Moistens and cleanses the mouth, begins chemical digestion?
Saliva
Enzyme that begins starch digestion?
Salivary amylase
Enzyme that digests fat after food is swallowed?
Lingual lipase
Binds and lubricates food?
Mucus
Enzyme that kills bacteria?
Lysozyme
Antibacterial antibody?
IgA
Extrinsic salivary glands
Beneath skin anterior to earlobe?
Halfway along the body of the mandible, medial to it’s margin?
Floor of mouth?
What is salivation coordinated by?
Parotid gland
Submandibular gland
Sublingual gland
The medulla oblongata
The muscular funnel That connects the Oral cavity to the esophagus is called?
The pharynx
Transports bolus to the stomach?
Esophagus
A straight muscular tube 25 to 30 cm long?
Esophagus
Where is the esophagus located?
In the mediastinum, posterior to the trachea
An opening where the esophagus meets the stomach?
Cardiac orifice
A burning sensation produced by acid reflux into the esophagus?
Heartburn
There are three phases of swallowing what are they?
Buccal phase
Pharyngo- esophageal phase
Peristalsis
How is swallowing Coordinated?
By the swallowing center in the medulla oblongata
Tongue collects food, forms Bolus, and pushes it into the oropharynx, this is called what ?
Buccal phase
The bolus is blocked from the oral cavity, nasal cavity, and larynx what phase is this?
Pharyngo- esophageal phase
This pushes the bolus down the esophagus to the stomach?
Peristalsis
What is chyme?
The pulpy acidic fluid that passes from the stomach to the small intestine, consisting of gastric juices and partly digested food.
The muscular sac in the upper left abdomen that holds up to 4 L of chyme is called what?
The stomach
What mechanically breaks up and liquefies bolus, begins chemical digestion of fat and protein?
The stomach
The stomach wall is made up of three things what are they?
Rugae
Muscularis which includes an inner oblique layer
Gastric pits
Longitudinal wrinkles of the mucosa and submucosa are called what?
Rugae
Depressions in the mucosa that lead to the gastric glands are called?
Gastric pits
The gastric glands produce 2 to 3 L of gastric juice or secretions per day composed mainly of what?
Water, HCl and pepsinogen
Protects The mucosa of stomach?
Mucus
Activates pepsinogen to pepsin and lingual lipase, breaks up connective tissue and cell walls, destroys pathogens?
Hydrochloric acid or HCl
The active Form is pepsin, it digest proteins?
Pepsinogen which is not active
This is essential for absorption of vitamins B12 by the small intestine?
Intrinsic factor
There are At least 20 different kinds Of these?
Chemical messengers
How often do contractions mix the bolus and gastric juices?
Every 20 seconds
How much chyme enters the duodenum at a time?
About 3 mL
A typical meal exits the stomach in about how many hours?
But it takes as long as ______ hours if the meal is high in fat?
Four hours
Six hours
The mucous coat, tight junctions, and replacement (cell division at the base of pits replace cells every 3 to 6 days) for what?
Protection of the stomach
Forceful ejection of stomach or intestine contents out of the mouth?
Vomiting
helicobacter pylori (bacteria) invade the mucosa of the stomach or duodenum and open the way for erosion by pepsin and HCl?
Peptic ulcer
Protrusion of part of the stomach into the thoracic cavity?
Hiatal hernia
There are three phases in the regulation of the gastric function, what are they?
Cephalic phase
Gastric phase
Intestinal phase (duodenum)
Gastric secretion stimulated by the sight, smell, taste or thought of food. The head is telling the stomach this is called?
Cephalic phase
Stomach telling itself to release gastric juices
ingested food stretches the stomach and results in stimulation of gastric secretion
Semi digested proteins stimulate the secretion of gastrin
Gastrin stimulates gastric secretions, accelerating protein digestion
Gastric phase
Peptides and amino acid in chyme stimulate the duodenum to secrete gastrin, which stimulates the stomach this is called?
Intestinal phase
Acid and fats trigger the duodenum to send an inhibitory signal to the stomach by way of the SNS, this is called?
Enterogastric reflex
The duodenum secretes ____________in response to fat in the chyme.
CCK stimulates _____________ ___________ And_____________ ______________.
CCK
Secretion bile and pancreatic enzymes
CCK or cholecystokinin
peptide hormone of the Gastrointestinal system responsible for stimulating the digestion fat and protein is called?
What does the duodenum secrete in response to acid chyme?
Secretin
What does secretin do?
It stimulates the liver and pancreas to secrete bicarbonate
CCK and secretin suppress what?
Gastric secretion and motility
Is the liver part of the digestive tract?
No it is not part of the digestive tract but it is part of the digestive system.
Where is the liver located?
Inferior to the diaphragm, filling most of the right side of the abdomen
Microscopic anatomy of the liver
Hexagonal cylinders are called?
Vein that passes down the core of the lobule is called?
Cuboidal cells forming sheets radiating from the central vein are called?
Hepatic lobules
Central vein
Hepatocytes
Microscopic anatomy of the liver continued
Blood-filled channel between hepatocytes?
Vein, artery, and bile ductile at the corners of a lobule that bring in blood and transport out bile?
Bile that is made by the hepatocytes passes into where?
Hepatic sinusoid
Hepatic triad
Bile ductules
How many functions do the hepatocytes have?
Over 500
Some Functions of the hepatocytes include:
Filter blood from where?
Absorb what for storage?
Remove and degrade hormones, toxins and what else?
Filter blood from stomach and intestines and arterial blood
Absorb glucose, amino acids, iron and vitamins for storage
Remove and degrade hormones, toxins, bile pigments and drugs
Functions of hepatocytes
Store glucose as glycogen and breakdown what?
Produce and secrete?
Where is bile produced?
Secrete albumin, lipoprotein, clotting factor, angiotensinogen, etc.
Store glucose as glycogen and breakdown stored glycogen
Produce and secrete bile
Bile is produced in the liver
What is inflammation of the liver, usually caused by a virus called?
Hepatitis
This organ stores the bile
The gallbladder
It is a sac on the underside of the liver that stores bile?
The gallbladder
Yellow-green fluid that emulsifies fat?
Bile
Bile is made up of what?
Bilirubin and bile acids
A pigment derived from decomposition of hemoglobin?
Bilirubin
Steroids synthesized from cholesterol which aid in fat digestion and absorption?
Bile acids
When does bile enter the gallbladder?
When bile fills the bile duct and overflows into the gallbladder
Between meals what does the gallbladder Absorb?
Water and electrolytes from the bile
What percentage of bile acids are reabsorbed in the ileum and return to the liver?
80%
Hard masses of cholesterol, calcium carbonate, and bilirubin are called?
Gallstones
Exocrine- ducts
Pancreas
Where is the pancreas located?
Posterior to the stomach
Exocrine tissue secretes?
Pancreatic juices
How do enzymes exit the pancreas?
Through the pancreatic duct
Pancreatic juices in their jobs:
Neutralizes HCl from the stomach?
Digest proteins when they’re converted to the active forms?
Digests starch?
Digest fats?
Digest RNA and DNA?
Sodium bicarbonate
Trypsinogen, chymotrypsinogen, procarboxypeptidase
Pancreatic amylase
Pancreatic lipase
Ribnuclease and deoxyribonuclease
Where is the small intestine located?
It is a coiled mass filling most Of the abdominal cavity inferior to the stomach
The first 25 cm or 10 inches, begins at the pyloric valve and arcs around the head of the pancreas?
Duodenum
Stomach acid is neutralized here?
Duodenum
In the small intestine fats are broken up by the _______ _________.
Bile acids
Pepsin is _______________ By increase in pH
Inactivated
What chemically digest here?
Pancreatic enzymes
This comes next in the small intestine and it is 1 to 1.7 m long?
Jejunum
Most of the nutrient digestion and absorption occurs here?
Jejunum
The circular folds are tallest and richly supplied with?
Blood
The longest part, name means it’s twisted. It’s also the last part and is 1.6 to 2.7 m long?
Ileum
Lymphatic nodules in clusters are called?
Peyer’s patches
Sphincter where ileum joins the cecum?
Ileocecal valve
Microscopic anatomy:
Transverse to Spiral ridges in mucosa and submucosa that slow chyme and promote mixing?
Fingerlike projections of mucosa covered with absorptive cells and goblet cells, lacteals and blood vessels are in the center of each?
Fuzzy brush border on absorptive cells that contain brush border enzymes (BBE)?
Circular folds
Villi
Microvilli
Microscopic anatomy continued:
Glands between the bases of the villi containing stem cells and cells that secrete defensive proteins?
Secretes bicarbonate rich mucus which neutralizes stomach acid?
Intestinal crypts
Duodenal glands
Intestinal motility:
Mixes chyme with secretions and brings it into contact with the mucosa?
Waves of contractions that milk chyme toward Colon?
Segmentation
Peristalsis
Inflammation of the intestine?
Crohn’s disease
Where is the large intestine located?
It begins with the cecum down to the blind pouch
Where is the appendix located? And what is it populated with?
It is attached the lower end of the cecum and is populated with lymphocytes.
This organ forms a frame around the small intestine?
The colon (ascending to sigmoid)
Muscularis externa longitudinal fibers are concentrated into three thickened strips which caused it to bunch up, this is called?
Taenia coli
Muscular tube that holds feces?
Rectum
Terminal and of large intestine?
Anus
Does the large intestine have circular folds or Villi?
No
This digests cellulose, pectin, and other polysaccharides
Synthesize B vitamins and vitamin K
Produces intestinal gas (flatus)
Reabsorb water and absorbs electrolytes
Takes 12 to 24 hours to reduce the residue of a meal to feces?
Bacterial flora
Strong contractions that move residue, 1 to 3 times per day?
Mass movement
The process of defecation?
Feces stretch the rectum and stimulate structure receptors, which transmit signals to the spinal cord
A spinal reflex stimulates contraction of the rectum and relaxes the internal anal sphincter
Defecation occurs when the external anal sphincter relaxes
Salivary amylase digest starch into?
Oligosaccharides
In the small intestine pancreatic amylase digest oligosaccharides to ________________?
Maltose
Disaccharides are digested by brush border enzymes to ________________?
Monosaccharides
Monosaccharides are absorbed by The small and testing using (________ ) ____________ _____________ ___________ ___________ , Solvent drag, or_________ _______________
Sodium glucose transport protein
Facilitated diffusion
And the stomach, pepsin digests _____________ into shorter _________________?
Protein
Polypeptides
Brush border enzymes remove __________ ___________ from Oligopeptides?
Amino acid
Amino acid absorption uses _______ Dependent co-transporters and _____________.
Na+
Diffusion
Bile breaks ____ ________ In the _________ Into smaller droplets?
Fat globules
Chyme
Lipase digest triglycerides to ________________ And two free fatty acid?
.
in the small intestine ___________, Formed of bile acids, absorb various __________?
Micelles
Lipids
Micelles transport _________ To the surface of the intestinal cells and lipids ________ Into the cells?
Lipids
Diffuse
In the cells the triglycerides are _____________ In packaged with other lipids into __________ __________ __________?
Resynthesized
Protein-coated chylomicrons (balls of fat)
Chylomicrons Are released from the cells and enter the __________ of the _________
Lacteals
Villi
Nucleases hydrolyze DNA and RNA to _____________.
Nucleotides
Brush border enzymes digest the nucleotides to _______ ______, ___________ & _______________ _________
Phosphate ion
Sugar
Nitrogenous base
Products are transported across the cells by _______________ _____________.
Membrane carriers
What are the fat-soluble vitamins?
A, D, E, K
What are the water-soluble Vitamins?
B’s & C
What vitamins are absorbed with other lipids?
Fat-soluble vitamins
What vitamins are absorbed by simple diffusion?
Water-soluble vitamins
How many liters a day of water does the digestive system receive?
9 L
How much water is absorbed by the small intestine?
8 liters
How many liters of water are absorbed buy the large intestine? The feces?
Large intestine 0.8 L
Feces 0.2 L
What happens when the large intestine and reabsorbs too little water?
Diarrhea
What happens when too much water is reabsorbed?
Constipation
