Digestive Foundations
Taking food into the mouth is this first digestive process.
What is ingestion?
This muscular tube connects the pharynx to the stomach.
What is the esophagus?
This acidic mixture of food and gastric juice leaves the stomach.
What is chyme?
This organ is the main site of digestion and nutrient absorption.
What is the small intestine?
Movement of digested nutrients from the intestinal lumen into the body is this process.
What is absorption?
Chewing breaks food into smaller pieces without changing its chemical composition. This is the type of digestion involved.
What is mechanical digestion?
This salivary enzyme begins starch digestion in the mouth.
What is salivary amylase?
This sphincter regulates the passage of stomach contents into the duodenum.
What is the pyloric sphincter?
These are the three small-intestinal regions in order from the stomach onward.
What are the duodenum, jejunum, and ileum?
These vessels within a villus directly receive absorbed monosaccharides and amino acids.
What are blood capillaries?
This innermost layer of the alimentary canal contacts food and performs secretion, absorption, and protection.
What is the mucosa?
The esophagus passes through the diaphragm at this opening.
What is the esophageal hiatus?
These gastric cells secrete hydrochloric acid and intrinsic factor.
What are parietal cells?
These fingerlike mucosal projections contain blood capillaries and a lymphatic capillary.
What are villi?
These deep ridges of mucosa and submucosa slow chyme movement and increase the area available for absorption.
What are circular folds?
A tissue sample contains blood vessels, lymphatic vessels, and the nerve plexus that regulates digestive secretions. It comes from this layer beneath the mucosa.
What is the submucosa?
A swallowed bolus moves toward the stomach through coordinated waves of contraction and relaxation. This process provides propulsion.
What is peristalsis?
Chief cells release an inactive precursor that becomes the protein-digesting enzyme pepsin. This is the precursor.
What is pepsinogen?
A microscope reveals tiny projections of individual intestinal epithelial cell membranes bearing digestive enzymes. Together they form the brush border.
What are microvilli?
Damage flattens intestinal villi. Even when digestive enzymes work normally, nutrient uptake falls mainly because this feature decreases.
What is absorptive surface area?
Intestinal contractions move chyme back and forth to mix it with enzymes, with little net forward movement. This pattern differs from propulsive peristalsis.
What is segmentation?
Acid repeatedly flows backward from the stomach into the esophagus. Failure of this sphincter to maintain closure most directly permits the reflux.
What is the lower esophageal sphincter?
A patient loses many parietal cells and can no longer produce enough intrinsic factor. Absorption of this vitamin is impaired even if dietary intake is adequate.
What is vitamin B12?
Acidic chyme enters the duodenum. Duodenal submucosal glands protect the lining by releasing alkaline mucus rich in this ion.
What is bicarbonate?
After a fatty meal, intestinal cells package absorbed long-chain fats into particles that first enter this lymphatic capillary in each villus.
What is a lacteal?