Digestive System Overview
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Questions and Answers

What is the primary function of the mouth in the digestive system?

  • Absorption
  • Digestion
  • Ingestion (correct)
  • Peristalsis

    • Which type of breakdown occurs through the action of salivary enzymes?

  • Segmentation
  • Mechanical breakdown
  • Absorption
  • Chemical breakdown (correct)

    • What is the main organ of absorption in the digestive system?

  • Stomach
  • Esophagus
  • Large intestine
  • Small intestine (correct)

    • What is the term for the muscle contractions that push food through the gastrointestinal tract?

    <p>Peristalsis</p> Signup and view all the answers

    What is the function of the large intestine in the digestive system?

    <p>Storage of feces</p> Signup and view all the answers

    Which type of muscular contraction occurs in segments along the organ?

    <p>Segmentation</p> Signup and view all the answers

    What is the purpose of mixing food in the intestines?

    <p>To slow down food progression down the intestines</p> Signup and view all the answers

    What type of epithelium makes up the peritoneum?

    <p>Simple squamous epithelium</p> Signup and view all the answers

    What is the function of the visceral peritoneum?

    <p>To wrap around organs</p> Signup and view all the answers

    What is the name of the double-layered fold that suspends the small intestine to the posterior abdominal wall?

    <p>Mesentery</p> Signup and view all the answers

    What is the outermost layer of the gastrointestinal tract?

    <p>Muscularis externa</p> Signup and view all the answers

    What is the function of the lamina propria in the mucosa?

    <p>To support the epithelium and detect pathogens</p> Signup and view all the answers

    Match the following peritoneal folds with their corresponding locations:

    <p>Lesser Omentum = From the liver to lesser curvature of stomach Greater Omentum = Hangs down from greater curvature of stomach, curves back up to the transverse colon Mesentery = Double layered peritoneum, suspends the small intestine to the posterior abdominal wall Parietal Peritoneum = Lines the abdominal cavity</p> Signup and view all the answers

    Match the following structures with their functions:

    <p>Parietal Peritoneum = Sits above pelvic organs, separate the abdominal cavity from the pelvic cavity Visceral Peritoneum = Lines multiple organs Retroperitoneal = Structures found behind the peritoneum, not in the peritoneal cavity Peritoneum = Lines the abdominal cavity, made of simple squamous epithelium and loose areolar connective tissue</p> Signup and view all the answers

    Match the following terms with their descriptions:

    <p>Visceral peritoneum = Double layered fold that wraps around organs Parietal peritoneum = Lines the abdominal cavity Retroperitoneal = Structures found outside the peritoneal cavity Mesentery = Double layered peritoneum, suspends the small intestine to the posterior abdominal wall</p> Signup and view all the answers

    Match the following anatomical locations with their corresponding peritoneal structures:

    <p>Abdominal cavity = Parietal Peritoneum Multiple organs = Visceral Peritoneum Posterior abdominal wall = Mesentery Pelvic cavity = Retroperitoneal</p> Signup and view all the answers

    Match the following peritoneal structures with their corresponding functions:

    <p>Parietal Peritoneum = Separates the abdominal cavity from the pelvic cavity Visceral Peritoneum = Lines multiple organs Mesentery = Suspends the small intestine to the posterior abdominal wall Retroperitoneal = Structures found outside the peritoneal cavity</p> Signup and view all the answers

    Match the following peritoneal structures with their corresponding descriptions:

    <p>Greater Omentum = Hangs down from greater curvature of stomach, curves back up to the transverse colon Lesser Omentum = From the liver to lesser curvature of stomach Mesentery = Double layered peritoneum, suspends the small intestine to the posterior abdominal wall Parietal Peritoneum = Lines the abdominal cavity</p> Signup and view all the answers

    What is the primary function of the tongue in the oral cavity?

    <p>To manipulate food and aid in swallowing</p> Signup and view all the answers

    What is the characteristic of primary teeth?

    <p>They are deciduous and fall out</p> Signup and view all the answers

    What is the function of taste buds on the tongue?

    <p>To detect harmful substances in food</p> Signup and view all the answers

    What is the shape of fungiform papillae?

    <p>Mushroom shape</p> Signup and view all the answers

    What is the location of circumvallate papillae?

    <p>Below the surface of the tongue</p> Signup and view all the answers

    What is the space between the cheeks and lips called?

    <p>Oral vestibule</p> Signup and view all the answers

    What is the main function of the laryngopharynx?

    <p>To separate the respiratory and digestive systems</p> Signup and view all the answers

    What is the term for the small mass of chewed food that is swallowed?

    <p>Bolus</p> Signup and view all the answers

    What is the function of the cardiac sphincter?

    <p>To prevent stomach contents from flowing back up into the esophagus</p> Signup and view all the answers

    What is the characteristics of the surface of the large intestine observed in histology?

    <p>It is smooth</p> Signup and view all the answers

    What is the purpose of the cementum in the tooth?

    <p>To attach the tooth to the alveolus</p> Signup and view all the answers

    What is the function of the tenia coli in the large intestine?

    <p>It causes sacculations in the large intestine</p> Signup and view all the answers

    What is the function of the epiglottis?

    <p>To protect the larynx from food</p> Signup and view all the answers

    What is the name of the part of the large intestine where lymph nodules are found?

    <p>Appendix</p> Signup and view all the answers

    What is the part of the stomach that receives the bolus?

    <p>Cardia</p> Signup and view all the answers

    What is the function of the pyloric sphincter?

    <p>To contract and prevent the contents of the stomach from leaving before it's been digested</p> Signup and view all the answers

    What type of muscle makes up the internal sphincter of the anus?

    <p>Smooth muscle</p> Signup and view all the answers

    What is the name of the layer of the tooth that is only found in the crown?

    <p>Enamel</p> Signup and view all the answers

    What is the function of the parasympathetic nervous system in the anus?

    <p>It relaxes the internal sphincter</p> Signup and view all the answers

    What is the terminal portion of the large intestine called?

    <p>Anal canal</p> Signup and view all the answers

    What is the function of the esophagus?

    <p>To push food from the pharynx to the stomach through peristalsis</p> Signup and view all the answers

    What is the name of the layer of the esophagus that is special to note because it is not in the abdominal cavity?

    <p>Adventitia</p> Signup and view all the answers

    What is the purpose of the chief cells in the gastric glands?

    <p>To secrete pepsinogen, an inactive form of the enzyme pepsin</p> Signup and view all the answers

    What is the function of the parietal cells in the gastric glands?

    <p>To secrete HCl to bring stomach pH to 2</p> Signup and view all the answers

    What is the name of the layer of muscle that is unique to the stomach and is composed of three layers?

    <p>Muscularis Externa</p> Signup and view all the answers

    What is the function of the rugae in the stomach?

    <p>To form folds in the stomach when it is empty</p> Signup and view all the answers

    What is the name of the region of the small intestine where most of the digestion and absorption of nutrients takes place?

    <p>Jejunum</p> Signup and view all the answers

    What is the function of the villi in the small intestine?

    <p>To increase the surface area of the small intestine for absorption</p> Signup and view all the answers

    What is the function of the lacteal or lymphatic capillaries in the small intestine?

    <p>To screen out harmful substances and pathogens</p> Signup and view all the answers

    What is the name of the glands found in the submucosa of the duodenum that produce alkaline mucus to neutralize acidity?

    <p>Brunner's glands</p> Signup and view all the answers

    What is the function of the microvilli in the simple columnar epithelium of the small intestine?

    <p>To increase the surface area of the small intestine for absorption</p> Signup and view all the answers

    What is the term for the partially digested food that enters the small intestine from the stomach?

    <p>Chyme</p> Signup and view all the answers

    What is the main function of serous cells in the parotid gland?

    <p>Producing enzymes to break down carbohydrates</p> Signup and view all the answers

    What is the characteristic of the submandibular gland?

    <p>It has a combination of serous and mucous alveoli</p> Signup and view all the answers

    What is the location of the pancreas?

    <p>In the abdominal cavity, behind the parietal peritoneum</p> Signup and view all the answers

    What is the function of the ducts in the salivary glands?

    <p>Releasing secretions onto the surface of the mouth</p> Signup and view all the answers

    What is the name of the part of the pancreas that is cupped into the C-shaped duodenum?

    <p>Head</p> Signup and view all the answers

    What type of epithelium lines the ducts of the salivary glands?

    <p>Simple cuboidal to simple columnar epithelium</p> Signup and view all the answers

    What is the main component of bilirubin?

    <p>Heme</p> Signup and view all the answers

    What is the function of the liver in storing vitamins?

    <p>To release vitamins into the bloodstream as needed</p> Signup and view all the answers

    What is the purpose of the liver's lipid metabolism?

    <p>To store and break down triglycerides, and synthesize cholesterol and lipoproteins</p> Signup and view all the answers

    What is the result of bilirubin not having a color?

    <p>There is an issue with the liver</p> Signup and view all the answers

    What is the function of the liver's glycogen metabolism?

    <p>To maintain a normal blood glucose level by breaking down glycogen to glucose and synthesizing glucose from other sources</p> Signup and view all the answers

    What is the role of the liver in protein metabolism?

    <p>To remove the amino group from amino acids and convert toxic ammonia into urea</p> Signup and view all the answers

    What is the main function of glucagon produced by the pancreas?

    <p>To raise blood glucose levels</p> Signup and view all the answers

    What is the name of the duct that carries bile from the liver and combines with the pancreatic duct to enter the duodenum?

    <p>Common Hepatic Duct</p> Signup and view all the answers

    What is the name of the structure that stores bile?

    <p>Gall Bladder</p> Signup and view all the answers

    What is the name of the layer of the gall bladder that is lined with simple columnar epithelium?

    <p>Mucosa</p> Signup and view all the answers

    What is the name of the duct that directly empties into the duodenum?

    <p>Accessory Pancreatic Duct</p> Signup and view all the answers

    What is the name of the structure that regulates the release of bile and pancreatic enzymes into the duodenum?

    <p>Sphincter of Oddi</p> Signup and view all the answers

    What is the name of the cells that line the sinusoids in the liver and are responsible for phagocytosis?

    <p>Kupffer cells</p> Signup and view all the answers

    What is the name of the liver lobes that are named for their shape?

    <p>Caudate lobe</p> Signup and view all the answers

    What is the name of the structure that stores bile and regulates its release into the duodenum?

    <p>Gall Bladder</p> Signup and view all the answers

    What is the name of the duct that combines with the pancreatic duct to enter the duodenum?

    <p>Common Bile Duct</p> Signup and view all the answers

    Study Notes

    Digestive System Part 2

    • Oral Vestibule: Space anterior to teeth and posterior to cheeks and lips. When you puff out your cheeks, this space is filled.

    • Oral Cavity Proper: Teeth and tongue are found here. Teeth and tongue participate in mechanical breakdown of food by chewing (mastication).

    • Taste Buds: Found on the surface of the tongue, they help detect harmful substances. Taste receptors are found around projections called papillae on the tongue.

    • Papillae: Projections on the tongue where taste buds are found. There are four types of papillae:

      • Filiform papillae: Sharp edges, like waves at a beach.
      • Foliate papillae: Boxy in shape, with three folds of lamina propria.
      • Fungiform papillae: Mushroom-shaped, projecting upward and expanding at the top.
      • Circumvallate papillae: Bubbly, extending below the surface of the tongue.

    Teeth

    • Primary Teeth (Deciduous): First set of teeth that come in, also known as milk teeth.
    • Permanent Teeth: Second set of teeth, formed between the mandible and maxilla, and are not lost.
    • Teeth Structure: Crown (superior), Neck (middle), and Root (inferior) make up the tooth structure.
    • Layers of Teeth: Enamel (crown), Dentin (bony region, found in crown, neck, and root), Pulp Cavity (contains blood vessels and nerves, found in crown), and Cementum (attaches tooth to alveolus).

    Pharynx

    • Pharynx: Region behind the nose, shared by the respiratory and digestive systems. Breath air through the pharynx and swallow food through the pharynx.
    • Three Parts of Pharynx: Nasopharynx (upper), Oropharynx (middle), and Laryngopharynx (lower).
    • Epiglottis: A cartilage that protects the larynx from food, preventing it from entering the respiratory tract.
    • Bolus: A small mass of chewed food that is swallowed.

    Esophagus

    • Esophagus: Part of the GIT in the thoracic cavity, responsible for pushing food from the pharynx to the stomach through peristalsis.
    • Layers of Esophagus: Mucosa (non-keratinized stratified squamous epithelium), Submucosa, Muscularis Externa (same inner circular and longitudinal layers), and Adventitia (outermost layer, special to the esophagus).

    Stomach

    • Stomach: Receives the bolus from the esophagus and is responsible for chemically and mechanically breaking down food.
    • Four Areas of Stomach: Cardia (receives bolus), Fundus (pouches upward), Body, and Pylorus (funnel-shaped).
    • Two Sphincters: Cardiac Sphincter (prevents stomach contents from flowing back into the esophagus) and Pyloric Sphincter (contracts to prevent stomach contents from leaving before being fully digested).
    • Stomach Layers: Mucosa (simple columnar epithelium with microvilli), Submucosa, Muscularis Externa (three layers: outer longitudinal, middle circular, and inner oblique), and Serosa (visceral peritoneum).

    Gastric Glands

    • Chief Cells: Secrete pepsinogen, an inactive form of the enzyme pepsin.
    • Parietal Cells: Secrete HCl, which mixes with pepsinogen to form pepsin, an active enzyme that breaks down protein.

    Small Intestine

    • Duodenum: First part of the small intestine, receives very acidic chyme from the stomach.
    • Jejunum: Middle part of the small intestine.
    • Ileum: Last part of the small intestine, has lymph nodes under the mucosa and submucosa.
    • Adaptations for Absorption: Length, folds, and villi increase the surface area for absorption.
    • Villi: Folds of mucosa and submucosa, composed of epithelium and lamina propria, increase the surface area for absorption.
    • Microvilli: Projections of plasma membrane and cytoplasm on top of columnar cells, further increasing the surface area for absorption.
    • Lacteal or Lymphatic Capillaries: Found in each villus, act as screeners to ensure only nutrients are absorbed.

    Peritoneum

    • Peritoneum: Lines the abdominal cavity, made up of simple squamous epithelium and loose areolar connective tissue.
    • Parietal Peritoneum: Lines the abdominal cavity, separates the abdominal cavity from the pelvic cavity.
    • Visceral Peritoneum: Lines multiple organs, double-layered folds.
    • Lesser Omentum: Connects the liver to the lesser curvature of the stomach.
    • Greater Omentum: Connects the greater curvature of the stomach to the transverse colon.
    • Mesentery: Suspends the small intestine to the posterior abdominal wall.

    Accessory Glands

    • Salivary Glands: Produce saliva that breaks down carbohydrates.
    • Parotid Gland: Produces enzymes that break down carbohydrates.
    • Sublingual Gland: Produces mucus that lubricates the bolus.
    • Submandibular Gland: Produces a combination of mucous and serous secretions.

    Pancreas

    • Pancreas: Found in the abdomen, retroperitoneal, and has three parts: head, neck, and tail.
    • Endocrine Function: Produces hormones like glucagon and insulin to regulate blood glucose levels.
    • Exocrine Function: Produces digestive enzymes that empty into the duodenum.
    • Pancreatic Ducts: Two ducts: the main pancreatic duct (duct of Wirsung) and the accessory pancreatic duct (duct of Santorini).

    Gallbladder

    • Gallbladder: Stores bile, which is produced by the liver.
    • Histology: Similar to the GIT, with a mucosa, muscular layer, and serosa.
    • Layers: Mucosa (simple columnar epithelium with microvilli), Muscular layer (smooth muscle), and Serosa (in the abdominal cavity and peritoneal cavity).

    Biliary Tract

    • Biliary Tract: Starts at the liver, where two ducts (right and left hepatic ducts) combine to form the common hepatic duct.
    • Common Bile Duct: Formed by the combination of the common hepatic duct and the cystic duct.
    • Ampulla of Vater: The common bile duct and pancreatic duct combine here, regulated by the sphincter of Oddi.

    Liver

    • Liver Functions: Produces bile, removes aged RBC, WBC, and bacteria from the blood, and regulates blood glucose levels.
    • Lobes: Right, left, quadrate, and caudate.
    • Hepatic Lobule: Hexagonal, with rows of hepatocytes (liver cells) arranged radially around a central vein.
    • Hepatocytes: Filter blood coming through, removing toxins and waste products.
    • Sinusoids: Blood passes through these rows of hepatocytes, getting filtered into the central vein.
    • Kupffer Cells: Phagocytic cells that line the sinusoids, removing pathogens and debris from the blood.
    • Portal Triad: Found at the corners of the hepatic lobule, contains branches of three vessels: the portal venule, hepatic arteriole, and bile duct.### Overview of the Digestive System
    • The digestive system consists of organs that make up the gastrointestinal tract (GIT) and additional organs that function in the digestive system but are not part of the GIT.

    Mouth Structures

    • The mouth contains salivary glands, tongue, and teeth.
    • Salivary glands produce salivary enzymes that break down food chemically.

    Gastrointestinal Tract

    • The GIT consists of the pharynx, esophagus, stomach, small intestine, large intestine, and anus.
    • Food passes through the GIT, undergoing mechanical and chemical breakdown.

    Functions of the Digestive System

    • Ingestion: the function of the mouth, tongue, and teeth to bring food into the body.
    • Digestion: the breakdown of food into smaller molecules.
    • Mechanical breakdown: occurs through chewing food with teeth, smushing food with the tongue, and muscle contractions.
    • Chemical breakdown: occurs through salivary enzymes produced by salivary glands.
    • Absorption: passes through the small intestine (main organ of absorption) and large intestine.
    • Storage of feces and release of feces (defecation) occur in the large intestine.
    • Peristalsis: muscle contractions that push food through the GIT.

    Types of Muscular Contractions

    • Peristalsis: sequential contractions along the path of the organ, from esophagus to small intestine.
    • Segmentation: contractions occur in segments along the organ at the same time, pushing food in both directions and mixing it.

    Peritoneum

    • The peritoneum lines the abdominal cavity and is made of simple squamous epithelium and loose areolar connective tissue.
    • It wraps around organs and has two areas: parietal peritoneum and visceral peritoneum.
    • Parietal peritoneum: lines the abdominal cavity, sits above pelvic organs, and separates the abdominal cavity from the pelvic cavity.
    • Visceral peritoneum: lines multiple organs and has double-layered folds.

    Retroperitoneal Structures

    • Structures found behind the peritoneum, not in the peritoneal cavity.
    • Examples: lesser omentum, greater omentum, and mesentery.

    General Histology of the Gastrointestinal Tract

    • The wall of the GIT has four layers from the esophagus to the anal canal.
    • The four layers are: mucosa, submucosa, muscularis externa, and serosa (not mentioned in the text).
    • Mucosa: consists of epithelium, lamina propria, and muscularis mucosa.
    • Submucosa: consists of connective tissue, glands, lymphatics, nerves, arteries, and veins.
    • Muscularis externa: consists of inner circular layer and outer longitudinal layer of smooth muscle.

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    Description

    Learn about the organs that make up the digestive system, including the mouth, pharynx, esophagus, stomach, and intestines. Discover the functions of the digestive system and the role of additional organs like salivary glands, liver, pancreas, and gallbladder.

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