Gastrointestinal System Flashcards
What are the main functions of the digestive system?
Take in food
Break food down into nutrient molecules
Absorb molecules into the bloodstream
Rid the body of indigestible remains
What are the two main groups of digestive system organs?
GI Tract (Gastrointestinal/Alimentary Canal) – Continuous muscular tube running from mouth to anus.
Accessory Digestive Organs – Includes teeth, tongue, gallbladder, and digestive glands.
What is the function of the GI Tract?
Digests food by breaking it into smaller fragments.
Absorbs nutrient fragments into the blood.
Includes organs such as mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus.
What are the accessory digestive organs?
Teeth – Helps in mechanical digestion.
Tongue – Assists in chewing and swallowing.
Gallbladder – Stores and concentrates bile.
Digestive glands – Secrete enzymes and substances to aid digestion:
Salivary glands
Liver
Pancreas
What are the major subdivisions of the digestive tract and their functions?
Oral Cavity, Teeth, Tongue – Mechanical processing, moistening, mixing with saliva.
Pharynx – Propels food into esophagus.
Esophagus – Transports food to the stomach.
Stomach – Chemical digestion by acid and enzymes; mechanical processing.
Small Intestine – Enzymatic digestion, absorption of nutrients.
Large Intestine – Water absorption and elimination of waste.
Salivary glands
Secrete enzymes for carbohydrate breakdown.
Liver
Produces bile for lipid digestion and stores nutrients.
Gallbladder
Stores and concentrates bile.
Pancreas
Produces digestive enzymes and hormones
What are the six essential activities in food processing?
What are the primary functions of the pharynx and esophagus in digestion?
The pharynx and esophagus serve as conduits to pass food from the mouth to the stomach. Their major function is propulsion, which starts with swallowing.
What are the two phases of swallowing (deglutition)?
Buccal phase: Voluntary contraction of the tongue.
Pharyngeal-esophageal phase: Involuntary phase involving the vagus nerve, controlled by the swallowing center in the medulla and lower pons.
What happens during the buccal phase of swallowing?
The upper esophageal sphincter is contracted (closed).
The tongue presses against the hard palate, forcing the food bolus into the oropharynx.
What occurs during the pharyngeal-esophageal phase of swallowing?
The tongue blocks the mouth.
The soft palate and uvula rise, closing off the nasopharynx.
The larynx rises, and the epiglottis blocks the trachea.
The upper esophageal sphincter relaxes, allowing food into the esophagus.
How does peristalsis aid in swallowing?
Peristalsis involves rhythmic contractions of the circular and longitudinal muscles in the esophagus, pushing food toward the stomach.
What is the role of the gastroesophageal sphincter?
The gastroesophageal sphincter opens to allow food into the stomach and then closes to prevent regurgitation.
What are the three regions of the pharynx?
Nasopharynx – Located behind the nasal cavity.
Oropharynx – Located behind the oral cavity.
Laryngopharynx – Located behind the larynx, leading to the esophagus.
What are the histological layers of the esophagus?
Mucosa – Stratified squamous epithelium.
Submucosa – Areolar connective tissue.
Muscularis externa – Includes circular and longitudinal muscle layers.
Adventitia – Fibrous connective tissue.
What is heartburn, and what causes it?
