Flashcards
Digestive Lecture Study Guide
Flashcards do conjunto (59)
- 1What is the overall function of the digestive system?To break down food into a usable (absorbable) form
To supply our cells with the nutrients they need for energy, growth, and repair - 2List, in order the organs that make up the gastrointestinal tract1.mouth(oral cavity)
2. pharynx (oropharynx and Laryngopharynx)
3. esophagus
4. stomach
5. small intestine
6. large intestine - 3List the accessory organs of digestion. What is the main defining difference between an organ of the GIT and an accessory organ?1. salivary glands
2. liver
3. gallbladder
4. pancreas
These organs participate in digestion but food never enters them - 4List & describe the processes involved in the functioning of the digestive system.1. ingestion
2. movement along the GI tract- voluntary (using skeletal muscle. ex: swallowing) and involuntary (using smooth muscle. ex: perstalsis)
3. Secretion- release of water, enzymes, acids, buffers, into GI
4. Mechanical processing-physical breakdown of food
5. chemical digestion- chemical breakdown of nutrients using enzymes
6. absorption
7. excretion - 5What is mechanical processing and wh does it involve?1. Mastication-chewing
2. emulsification- used in the liver to break down fat into smaller pieces
3. mixing waves- in stomach, churning and smooshing food into liquid chyme
4. segmentation- in small intestine, pushing and smooshing food into smaller pieces - 6what is chemical digestion and what does it involve?The chemical breakdown of nutrients in food; disassembling of organic molecules (carbs, proteins, lipids) into component parts using enzymes
- 7What are the 6 classes of nutrients?1. Carbohydrates
2. proteins
3. fats/lipids
4. vitamins
5. minerals
6. water - 8What is the name of the involuntary movement of food through the GIT?peristalsis
- 9What is involved in the chemical digestion of carbohydrates?starch (a polysaccharide/complex carb) is broken down into maltose (a disaccharide) by the enzyme amylase (secreted from the salivary glands and pancreas)
Disaccharides:
-Maltose is broken down into two glucose molecules by the enzyme maltase
-Sucrose is broken down into glucose and fructose by sucrase
-Lactose is broken down into glucose and galatose by enzyme lactase
(each of these enzymes are found in the small intestine) - 10What is involved in the chemical digestion of proteins?-Proteins are broken down into polypeptides by the enzyme pepsin(produced in our stomach)
-polypeptides are broken down into di/tripeptides by pancreatic protease enzymes
-di/tripeptides are broken down into amino acids by small intestinal peptidases - 11What is involved in the chemical digestion of lipids?Lipids (triglycerides) are broken down into 2 fatty acids and a monoglyceride by the enzyme lipase
- 12What is the process of absorption?The movement of nutrients from GIT into blood capillaries (monosaccharides, amino acids, H2O, vitamins, minerals)
or lymphatic capillaries (fatty acids)
- this occurs after chemical processing - 13What is deglutination? What is deglutination apnea?Deglutination-the process of swallowing
Deglutination apnea- the inability to breath and swallow at the same time - 14Name the four histological layers associated with organs of the GITInnermost to outermost
1. Mucosa
2. Submucosa
3. Muscularis layer
4. Serosa - 15What is the mucosa layer made up of?1. epithelium- either simple or stratified. In oral cavity and esophagus- stratified squamous non-keratinized (for wear and tear). In the stomach, small intestine, and most of large intestine- simple columnar for secretion and absorption
2. lamina propria- located deep to the epithelium. made of loose areolar CT. contains blood vessels, lymphatic vessels
3. muscularis mucosae- narrow band of smooth muscle and elastic fibers - 16What is the submucosal layer made up of?A layer of areolar CT containing blood vessels, nerves, and lymphatics
- 17What is the muscularis layer made up of?Muscularis layer (muscularis externa)
Skeletal muscle at beginning & end
of GIT, smooth muscle (inner
circular; outer longitudinal layer)
from lower esophagus to rectum.
These two layers of smooth muscle help mechanically process and propel materials along the digestive tract. - 18What is the serosa layer made up of?Serous membrane for organs inside the abdominal cavity is called the visceral peritoneum.
For organs outside of the abdominal cavity such as the pharynx, esophagus, and rectum the serosa layer is called adventitia and made of collagen fibers. - 19Describe the locations of the peritoneum (parietal & visceral)parietal peritoneum- lines the wall of the abdominal cavity
visceral peritoneum- lines organs within the abdominal cavity - 20What are mesenteries? What are the four mesenteries and what organs are associated with them?Mesenteries-folds of peritoneum that help stabilize organs, enclose blood vessels, nerves, lymphatics
1. greater omentum- associated with the greater curvature of the stomach
2. lesser omentum- associated with the lesser curvature of the stomach.
3. mesentery proper- holds the small intestine in place
4. mesocolon- attaches and stabilizes the large intestine to itself and the abdominal wall. - 21Describe the anatomical features of the oral cavity. What type of epithelial tissue makes up the mucosal lining?1. vestibule- between the teeth and lips
2. oral cavity proper- roof: hard palate, soft palate. floor: tongue
-Mucosa is made up of stratified squamous non-keratinized epithelium (except over
hard palate (keratinized)
-oral cavity connects to the oropharynx at the fauces. - 22Describe the structure of the tongue. Name the types of papillae found on the surface. Which ones contain taste buds & which ones do not?The tongue is comprised of skeletal muscle covered with stratified squamous.
Papillae:
1. filiform- NO taste buds, cover majority of the surface to roughen tongue
2. fungiform- have taste buds, cover surface
3. vallate (circumvallate)- have taste buds, cover posterior tongue
4. foliate- have taste buds, cover lateral surface of tongue - 23What do the intrinsic muscles control? extrinsic?intrinsic- change shape of tongue. originate and insert within tongue
extrinsic- allow for gross movement in/out of mouth and side to side. originate near hyoid bone. - 24Name the three sets of salivary glands and describe their locations.Salivary glands- secrete saliva and salivary amylase
1. parotid- lies superficial to the masseter muscle
2. submandibular- underneath the angle of the mandible
3. sublingual- embedded underneath - 25What is saliva made up of? What is it needed for?Saliva is made of water, salts, mucins, and salivary amylase.
it moistens food, dissolves chemicals, and stimulates taste buds - 26What is the function associated with our teeth? What are the 4 types of teeth?2 sets: 20 deciduous (baby teeth) appear at 6 months and fall out around 6 years old.
32 permanent teeth.
Incisors: 4 front teeth
Cuspids/canines
Bicuspids/premolars
molars - 27What are the parts of the tooth>crown- exposed portion made of dentin tissue
pulp cavity- filled with CT pulp
neck- gingival border
root- in mandible/maxilla, has root canal with BV's and nerves (CNV) surrounded by cementum. - 28Name the three parts of the pharynx. What type of epithelial tissue makes up the mucosal lining of each section? Explain why there is that difference.1. Nasopharynx- pseudociliated stratified columnar epithelium to move mucous
2. oropharynx- stratified squamous
3. laryngopharynx- stratified squamous
for protection against wear and tear - 29What is the function of the uvula? What is the function of the epiglottis?uvula- raises up and blocks food from entering nasopharynx
epiglottis- directs food from laryngo to esophagus so it doesn't go into the glottis (opening for airway) - 30Describe the anatomical features of the esophagus, including the type of epithelial tissue in the mucosal layer, and the type of muscle tissue in the muscularis layer. What digestive functions are associated with the esophagus?Esophagus: muscular tube that runs from laryngopharynx to diaphragm to lower cardiac sphincter.
-mucosal layer: non-keratinized stratified squamous
-submucosa: contains glands.
-muscularis layer: muscle varies. first third (1/3) is skeletal muscle, 2/3 is a mix of skeletal and smooth muscle, and last third is smooth muscle.
▪ functions in “deglutition” through
action of peristalsis - 31Describe the basic anatomy of the stomach, including the regions, curvatures, associated mesenteries and sphinctersThe stomach lies left of the midline. it attaches to the esophagus at the gastroesophageal junction.
-within the junction is a thickening of smooth muscle called lower esophageal sphincter/cardiac sphincter.
-pyloric sphincter: connects the stomach to the duodenum, regulates outflow.
-greater curvature: left/lateral, and greater omentum attaches here and folds over organs as fatty tissue.
lesser curvature: right/medial, and lesser omentum attaches here and extends to liver/beginning of duodenum - 32What is the purpose of gastric folds (rugae) ?Mucosal epithelium – simple columnar with gastric folds (rugae) that allow
for distension. folds flatten as stomach fills - 33What type of epithelial tissue is found in the mucosa of the stomach? What modifications to the basic histological structure of the GIT are seen within the muscularis of the stomach?mucosal epithelium- simple columnar epithelium for secretion and absorption with gastric folds (rugae) for streching. In between rugae are downward depressions called gastric pits located within the lamina propria.
3 layers of smooth muscle: these layers allow for mixing waves to liquify food and make chyme.
1. outer longitudinal
2. middle circular layer
3. innermost oblique layer - 34What cells are found in the gastric glands? What does each cell type secrete and for what purpose? Why does the stomach secrete pepsinogen and not pepsin?In gastric pit:
-mucous neck cells to secrete mucous to lubricate and protect epithelial cells from enzymes and acid
In gastric gland:
-Parietal cells secrete HCL for protein digestion and intrinsic factor for vitamin B12 absorption
-Chief cells (peptic cells) secrete pepsinogen that interacts with HCL and gets converted to pepsin, a protein digesting enzyme - 35What are the overall functions of the stomach?1. Temporary storage of food
2. mechanical breakdown of food to chyme via mixing waves
3. produce intrinsic factor for vitamin B12 absorption
4. Begin chemical digestion for proteins (proteins broken down by pepsin and HCL to polypeptides) - 36Describe the basic anatomy of the small intestine. What are the main functions of the small intestine?-connects stomach to large intestine. more narrow than large intestine
-held together by mesentery proper
-chemical digestion is completed here and nutrients absorbed - 37What are the 3 regions of the small intestine and what are their functions?1. duodenum- (10 inches) receives chyme from stomach and secretions from liver, gallbladder, and pancreas
2. jejunum- (8 feet) most digestion and absorption occurs here
3. Ileum- (12 feet) connects to cecum of large intestine and ileocecal valve - 38Name and describe the modifications seen within the mucosa and submucosa of the small intestine. Why are these modifications important?-Modifications in mucosa & submucosa to
increase functional surface area
Modifications:
▪ Plicae circulares (circular folds) – large transverse ridges; most abundant in
jejunum
▪ Villi – small finger-like projections of mucosal folds across surface of
intestine. Between villi are intestinal crypts (intestinal glands) stem cells in crypts replace old absorptive cells. - 39What are the functions of the absorptive cells of the small intestine?Villi lined with “absorptive cells” - mucosal epithelium of simple columnar
-epithelium with microvilli “brush border”. these cells also produce
enzymes (disaccharidases & peptidases) for final digestion of carbs and proteins
▪ lamina propria of each villus contains a capillary network & a “lacteal”
(lymphatic capillary) for absorption of nutrients - 40What is a lacteal and what is its purpose?Lacteal- a lymphatic capillary that absorbs extra interstitial fluid and allows for absorption of long chain fatty acids, and then lymph will be returned to the blood at subclavian veins
- 41where are fats absorbed?Into the lymphatic system.
-the long chain fatty acids can't be absorbed effectively in blood capillaries. - 42Describe the anatomical location and structure of the pancreas.Located deep within the abdominal cavity, a flat organ posterior to the stomach extending from duodenum to spleen. has three major regions:
1. head
2. body
3. tail (by spleen) - 43What enzymes are found in “pancreatic juice”?-Juice contains mixture of enzymes and buffers (which are secreted by acinar cells into pancreatic duct and then into duodenum) Enzymes:
1. pancreatic amylase- to convert starch to maltose
2. lipase- to break down lipids
3.proteases- to break down proteins into di/tripeptides
4.nucleases- digest DNA/RNA - 44What is the function of sodium bicarbonate in pancreatic juice?sodium bicarbonate – neutralizes acidic chyme
because enzymes in small intestine need an alkaline pH - 45How does the pancreatic juice get from the pancreas to the small intestine? What part of the small intestine will the pancreatic juice enter?through the pancreatic duct, where it meets the bile duct and the two empty into the duodenal ampulla
- 46What is the difference between the functions of endocrine and exocrine glands in the pancreas?Endocrine- (pancreatic islets of langerhans) secretes insluin and glucagon
Exocrine- (pancreatic acini) secretes pancreatic juice through pancreatic ducts to duodenum - 47Name the lobes of the liver. What tissue separates the right & left lobe?There are 4 lobes of the liver:
1. Right-very large
2.Left
3. Caudate (by IVC)
4. Quadrate (by gall bladder)
The left and right lobes are separated by the falciform ligament, which continues at inferior margin as ligamentum teres (round ligament) - 48Describe the microscopic anatomy of liver lobules. What are sinusoids? What types of cells are found within lobules and which are found in the sinusoids? Which cells within the liver are phagocyticLobules- comprised of rows of hepatocytes arranged radially around a central vein
Sinusoids- highly fenestrated capillaries, surrounded by hepatocytes, partially lined with phagocytic kupffer cells (phagocytic cells for immunity and defense.
-Portal area at each corner of lobule = “Triad” - branch of bile duct, hepatic artery, hepatic portal vein - 49What is bile? Which cells produce bile? Where is it stored? What is the function of bile?Bile is made of mostly water with small amounts of ions, and bilirubin(pigment derived from hemoglobin)
Bile is synthesized by hepatocytes of the liver, stored in the gallbladder and secreted into the duodenum.
-The function of bile is to dilute and buffer acids in the chyme as it enters the small intestine, emulsification of lipids, absorption of fats (due
to presence of bile salts), & excretion of bilirubin - 50Describe the path that bile must follow to get out of the liver.1. Bile gets directly secreted into bile canaliculi of lobule.
2. Bile canaliculi merge to form bile ducts
3. Bile ducts merge to eventually create the right & left hepatic ducts
4. R and L hepatic ducts unite to form the common hepatic duct.
5. the common hepatic duct merges with the cystic duct of gall bladder to form common bile duct.
6. The common bile duct joins the pancreatic duct & enters the duodenum at the greater (major) duodenal papilla - 51What happens to the bile produced by the liver if there are no fats present in the GIT at the moment?Between meals, when there's no fat that needs to be digested, most of the bile flows into the gallbladder instead, where it is concentrated and stored.
Also when no fat is found, the sphincter will stop the release of pancreatic juice and bile into the small intestine. - 52Describe the various functions of the liver.emulsification
makes plasma proteins
stores nutrients, releases when needed
can convert nutrients into glucose - 53Describe the dual blood supply to the liver. Why is this necessary?The liver receives oxygenated blood from the hepatic artery as well as deoxygenated nutrient rich blood from hepatic portal vein that gets it from digestive organs.
It is necessary so that the liver can perform its various major functions - 54Where is the gallbladder located? What is its function? Describe the anatomy of the bile ducts and associated structures (hepatopancreatic (duodenal) ampulla, duodenal papilla) that connect liver/gallbladder/duodenum.hollow muscular sac under right lobe of liver; stores & concentrates bile; releases
bile through cystic duct.
▪ Right & left hepatic ducts unite to form common hepatic duct which merges with cystic duct of gall bladder to form common
bile duct which joins with pancreatic duct and enters the duodenum at the greater (major) duodenal papilla - 55Describe the anatomy of the large intestine. What are the regions of the large intestine?-Attached to the ileum of the small intestine at the ileocecal sphincter (5 in long).
-suspended in the abdominal cavity by the mesocolon.
-the cecum is attached to the ileum and extends inferior to it with the appendix attached.
regions of the colon:
1. ascending- along R side curves at hepatic flexure
2. transverse- runs horizontally, curves on L side at splenic flexure
3. Descending- L side, gradually curves
4. sigmoid- portion after the gradual curve and extends to rectum - 56What type of tissue lines the large intestine? what modifications in muscularis layer and serosa?Mucosa: simple columnar epithelium
*no plicae circularis or villi
Modifications in muscularis layer:
-2 layers of smooth muscle- inner circular layer and outer longitudinal.
-longitudinal muscle layer forms bands called "teniae coli" which create pouches of haustra
-serosa is not a complete serous membrane. Pieces of serous membrane with adipose tissue. The serosa forms omental appendices (epiploic appendages) that look like fat tags. - 57What are the functions of the large intestine?1. reabsorption of water and electrolytes
2. absorption of some vitamins produced by bacteria; ex- vitamin K is produced by bacteria in the large intestine
3. formation and temporary storage of fecal mater prior to defecation - 58What tissues are present in the anal canal?Anal canal will be stratified squamous non keratinized, very end will be keratinized.
- 59Does any enzymatic digestion occur in the large intestine?*all chemical digestion has been completed, so no chem digestion takes place here*
-although there is some bacterial "digestion"
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- Anatomy Final Exam - Digestive, Urinary, Reproductive FlashCards sobre Digestive Lecture Study Guide, criado por Jessica Do em 22-05-2022.
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