Chapter 21 - Digestive System Flashcards
What structures make up the “GI Tract?”
Stomach and Instestines
What organs and openings make up the Digestive System?
Mouth, Pharynx, Esophagus, Stomach, Small Intestine, Large Instestine, Anus
What is the word to describe the introduction of food into the stomach?
Ingestion
What is mastication?
Chewing, mechanically breaking down food
What is propulsion?
The movement of the food through the GIT.
What is the word to describe moving the bolus from the oral cavity to the esophagus.
Deglutition
What is peristalsis?
Movement of material through the digestive tract.
What are the two waves of peristalsis?
Wave of relaxation: Muscle relaxes in front of the bolus.
Wave of contraction: Muscle contracts behind the bolus to move it forward.
What components help with secretion?
Mucus, water, bile, and enzymes.
What is digestion?
The mechanical and chemical breakdown.
What is absorption?
Movement from tract into the circulation or the lymph.
What is the name of the process of removing waste products from the body?
Elimination
What are the 4 layers of the digestive tract tissue?
Mucosa
Submucosa
Muscularis
Serosa
What are the 3 sublayers of the mucosa?
Mucous Epithelium
Lamina Propria
Muscularis Mucosae
What are the two layers of smooth muscle fibers found in the muscularis tunic of the Digestive Tract ?
Circular
Longitudinal
What membrane lines the abdominal cavity and its organs?
Peritoneum
What are the two types of peritoneum?
Visceral peritoneum
Parietal peritoneum
What are the functions of the lips and the cheeks?
Important in mastication and speech.
Describe the two types of muscles of the tongue?
Intrinsic Muscles: Change shape of tongue
Extrinsic Muscles: Protrude and retract tongue and move it side to side.
What is the tissue that attach the tongue to the floor of the oral cavity?
Lingual frenulum
What is the role of the tongue?
Moves food in mouth and participates in speech and swallowing.
What are the two sets of teeth?
Deciduous: “baby teeth”
Permanent: adult teeth that replace baby teeth between 5-11 years.
What are the 4 types of teeth?
Incisors, canines, premolars and molars.
Where are the anatomical crown and clinical crown?
Anatomic crown: Enamel-covered part of tooth.
Clinical Crown: Section of tooth above gum line
What is the name of the enameled part of the tooth beneath the gum line?
Neck
What structure is responsible for holding the tooth in the socket?
Periodontal Ligaments
What are the three salivary glands?
Parotid
Submandibular
Sublingual
What is the role of saliva?
Prevents bacteria infection, lubrication, initiates process of digestion, helps to form bolus.
What is the only function of the esophagus?
To transport the food to the stomach. From the pharynx to the stomach.
What is the area called where the esophagus passes through the diaphragm?
Esophageal hiatus.
What is a sphincter?
A muscular ring
What is deglutition?
Swallowing
What are the three phases of deglutition?
Voluntary: Bolus is moved by tongue from oral cavity to pharynx.
Pharyngeal: Involuntary reflex where pharynx opens into the esophagus and food is pushed into esophagus.
Esophageal: Involuntary reflex where peristalsis contraction pushes food from esophagus into the stomach.
What are the two openings into the stomach?
Gastroesophageal (cardiac): upper opening from esophagus to stomach.
Pyloric: lower opening from stomach to duodenum.
What are the main parts of the stomach (4)?
Cardiac: superior opening into stomach.
Fundus: superior rounded area of stomach.
Body: Largest part of stomach.
Pylorus: funnel shaped area which controls movement out of the stomach.
What are the two curvatures of the stomach?
Greater and Lesser curvatures.
What are the two sphincters of the stomach?
Cardiac: Part of lower esophagus.
Pyloric: Between lower stomach and small intestine.
What are the 4 layers of the stomach wall?
Mucosa
Submucosa
Muscularis
Serosa
What are the three muscular layers of the muscularis of the stomach wall?
Inner Oblique
Middle Circular
Outer Longitudinal
What are the large wrinkles called within the stomach?
Rugae
What are gastric pits?
Openings for gastric glands
What are the 5 types of epithelial cells of the stomach?
Surface mucus cells
Mucous neck cells: deep
Parietal cells: secrete hydrochloric acid
Chief Cells: Secrete Pepsinogen - digestive enzyme
Endocrine Cells: secrete hormones
What is chyme?
Ingested food plus stomach secretions
What is the function of hydrochloric acid in the stomach?
Kills bacteria
Digestion
What are the two types of waves that move liquid in the stomach?
Mixing Waves (80%)
Peristalic Waves (20%)
What happens to the cardiac and pyloric sphincters during waves in the stomach?
They are closed
Where in the digestive system is the greatest amount of digestion and absorption of nutrients?
Small Intestine
What are the three divisions of the small intestine?
Duodenum: First 10 inches of small intestine
Jejunum
Ileum
What is the function of the deodenum?
The second area of digestion if the stomach didn’t digest everything. Pancreatic glands produce enzyme to help duodenum digest rest of food.
What is the reason that there are circular folds, villi and microvilli in the intestines?
Increases surgace area so that there is more room for absoption.
What are the four cells found in the duodenum?
Absorptive cells: produce digestive enzymes and absorb food.
Goblet CElls: produce protective mucus
Endocrine cells: produce regulatory hormones
Granular cells: help protect from bacteria
What changes when the duodenum changes into the jejunem and ileum?
Decrease in diameter, thickness of intestinal wall, number of circular folds and number of villi.
Where is the major site of nutrient absorption in the intestines?
Jejunum and Ileum
Where is the ileocecal junction?
Where the ileum meets the large intestine.
What is the porta?
The area of the liver where vessels, ducts, nerves exit and enter the liver.
Describe the organization of ducts in the liver.
Right and Left Hepatics —> Common Hepatic.
Common Hepatic + Cystic Duct —-> Common Bile
What is the function of bile?
Used to emulsify fat
Where is bile produced and stored?
Bile is produced in the liver and stored in the gallbladder.
What are the cells that make up the liver called and what are their functions?
Hepatocytes
Bile production, detox, phagocytosis.
What is the function of the gallbladder?
To store bile and release it
What makes up the large intestine?
Consists of cecum, colon, rectum, anal canal
What is the movement of chyme through the large intestine?
Sluggish movement 18-24 hours
What is absorbed in the large intestine?
Water, salt, vitamins and medicine.
What is the blind sac of the large intestine that gathers chyme before it goes through the large intestine?
Cecum
What are the 4 portions of the colon?
Ascending, Transverse, descending, sigmoid
What are the two sphincters of the large intestine?
Internal anal sphincter: Involuntary control, smooth muscle
External anal sphincter: Voluntary control, skeletal muscle.
What are the accessory organs of the digestive system?
Salivary glands
Liver
Gallbladder
Pancreas
