Topic 5.1: Digestion Flashcards
List the parts of the human digestive tract that food passes through, and note whether chemical and/ or mechanical digestion occurs.
Mouth-Mechanical and chemical
Pharynx- No aid in digestion
Esophagus- No aid in digestion
Stomach- Mechanical and chemical
Small intestine- Chemical
Large intestine- Small amount of chemical by bacteria
Compare the major functions of the small intestine and the large intestine.
The small intestine processes food for digestion and absorbs nutrients. Its lower part, the ileum, is involved in immune responses.
The large intestine absorbs water, salts, and some vitamins, and eliminates indigestible material as feces.
Discuss strategies that might help obese people lose weight by inhibiting the secretion and/or activity of certain hormones.
Hormones that increase digestive activity include gastrin, secretin, and CCK. Inhibiting these might regulate weight but they can cause difficulties in digesting food, leading to excess gas or constipation.
Define digestive system
Organ system that consists of digestive organs (stomach, intestines, etc.) and accessory organs (liver, etc.); ingests and digests food; absorbs nutrients and eliminates wastes.
Define mouth
In humans, organ of the digestive tract where food is chewed and mixed with saliva.
Define salivary glands
In humans, gland associated with the mouth, that secretes saliva.
Define pharynx
In vertebrates, common passageway for both food intake and air movement; located between the mouth and the esophagus.
Define esophagus
Muscular tube for moving swallowed food from the pharynx to the stomach.
Define peristalsis
Wavelike contractions that propel substances along a tubular structure such as the esophagus.
Define lumen
Cavity inside any tubular structure, such as the lumen of the digestive tract.
Define stomach
In vertebrates, muscular sac that mixes food with gastric juices to form chyme, which enters the small intestine.
Define chyme
Thick, semiliquid food material that passes from the stomach to the small intestine.
Define small intestine
In vertebrates, the portion of the digestive tract that precedes the large intestine. In humans, consists of the duodenum, jejunum, and ileum.
Define duodenum
First part of the small intestine, where chyme enters from the stomach.
Define jejunum
Region of the small intestine located between the duodenum and ileum.
Define ileum
Region of the small intestine; connects the jejunum and large intestine.
Define villus
Small, fingerlike projection of the inner small intestinal wall.
Define lacteal
Lymphatic vessel in an intestinal villus; aids in the absorption of fats.
Define large intestine
In vertebrates, portion of the digestive tract that follows the small intestine. In humans, consists of the cecum, colon, rectum, and anal canal.
Define cecum
Region of the large intestine, just below the small intestine, to which the appendix is attached.
Define appendix (vermiform appendix)
In humans, small, tubular appendage that extends outward from the cecum of the large intestine.
Define vestigial structure
Remnant of a structure that was functional in some ancestor but is no longer functional in the organism in question.
Define anus
Outlet of the digestive tube.
Define fiber
General term for indigestible plant material, typically complex carbohydrates such as cellulose.
Review what it means to say that the pancreas has both endocrine and exocrine functions.
The pancreas secretes hormones (endocrine) such as insulin and glucagon into the blood, and also secretes digestive enzymes (exocrine) into the small intestine by way of ducts.
List what each accessory gland contributes to the process of digestion.
Salivary glands produce saliva, which moistens food and contains amylase, which begins the digestion of starch.
The liver detoxifies blood by removing and metabolizing poisonous substances, stores iron and vitamins A, D, E, K and B12, makes many plasma proteins, such as albumins and fibrinogen, from amino acids, stores glucose and glycogen after a meal, and breaks down glycogen to glucose to maintain the glucose concentration of blood between eating periods, produces urea after breaking down amino acids, removes bilirubin, a breakdown products oof hemoglobin from the blood, and excretes in in bile, a liver product, and helps regulate blood cholesterol level, converting some bile salts.
The main function of the gallbladder is to store bile. The pancreas secretes bicarbonate, digestive enzymes, and the hormones insulin and glucagon.
Explain why the liver is necessary for life, whereas the gallbladder can be removed with few consequences.
The gallbladder stores bile and people can live without this function. The liver has essential functions of detoxification, storage, synthesis, lipid regulation, and hemoglobin breakdown, all of which are necessary for survival.
Define liver
Large, dark red internal organ that produces urea and bile, detoxifies the blood, stores glycogen, and produces the plasma proteins, among other functions.
Define bile
Secretion of the liver that is temporarily stored and concentrated in the gallbladder before being released into the small intestine, where it emulsifies fat.
Define pancreas
Internal organ that produces digestive enzymes and the hormones insulin and glucagon.
Define gallbladder
Organ attached to the liver that serves to store and concentrate bile.
Define gallbladder
Organ attached to the liver that serves to store and concentrate bile.
Define gallbladder
Organ attached to the liver that serves to store and concentrate bile.
Describe where in the digestive tract the chemical digestion of each of the following types of nutrients occurs: carbohydrates, proteins, and fats.
Carbohydrate digestion begins in the moth, with salivary amylase, and continues in the small intestine, due to maltase and pancreatic amylase.
Protein digestion begins in the stomach, where pepsin breaks proteins into peptides, and continues with trypsin and peptidases in the small intestine.
Fats are mainly digested by pancreatic lipase in the small intestine.
Identify the final molecule (monomer) resulting from the digestion of carbohydrates, proteins, and fats.
Carbohydrates are broken down to glucose; proteins to amino acids; fats to glycerol and fatty acids.
Explain how the structure of the digestive system assists in regulating the digestive enzymes.
The digestive system is divided into many compartments, each of which has a distinctive internal environment and pH. These differences contribute to regulation of digestive enzymes.
Define salivary amylase
In humans, enzyme in saliva that digests starch to maltose.
Define pepsin
Enzyme secreted by gastric glands that digests proteins to peptides.
Define pancreatic amylase
Enzyme that digests starch to maltose.
Define trypsin
Protein-digesting enzyme secreted by the pancreas.
Define lipase
Fat-digesting enzyme secreted by the pancreas.
Define peptidase
Intestinal enzyme that breaks down short chains of amino acids to individual amino acids that are absorbed across the intestinal wall.
Define maltase
Enzyme produced in small intestine that breaks down maltose to two glucose molecules.
The digestive system consists of a series of tissues surrounding a hollow space called the
a) serosa
b) mucosa
c) lumen
d) muscularis
c) lumen
The large intestine
a) digests all types of food
b) is the longest part of the intestinal tract
c) absorbs water
d) is connected to the stomach
e) is subject to hepatitis
a) digests all types of food
This organ may be part of the immune system and helps prevent infections in the large intestine.
a) duodenum
b) rectum
c) cecum
d) appendix
d) appendix
This structure blocks the opening to the respiratory system during swallowing.
a) esophagus
b) pharynx
c) epiglottis
d) salivary gland
c) epiglottis
Which of the following is incorrect regarding gastric juice?
a) it is provided by the pancreas
b) it contains pepsin to digest protein
c) it has a pH of 2 due to hydrochloric acid
d) it is produced by the gastric glands
a) it is provided by the pancreas
Bile
a) is an important enzyme for the digestion of fats
b) cannot be stored
d) emulsifies fat
e) all of these are correct
d) emulsifies fat
Which of the following is not a function of the liver in adults?
a) produces bile
b) detoxifies alcohol
c) stores glucose
d) produces urea
e) makes red blood cells
e) makes red blood cells
What is the exocrine function of the pancreas?
a) secrete insulin and glucagon
b) make plasma proteins
c) produce sodium bicarbonate and digestive enzymes
d) convert cholesterol into bile salts
a) secrete insulin and glucagon
Which of these could be absorbed directly without need of digestion?
a) glucose
b) nucleic acid
c) fat
d) protein
e) all of the above
a) glucose
Which association is incorrect?
a) protein- trypsin
b) fat-lipase
c) maltose-pepsin
d) starch- amylase
e) protein-pepsin
c) maltose-pepsin
Which of the following nutrients are loaded into chylomicrons and transported by the lymphatic system following digestion?
a) carbohydrates
b) fats
c) proteins
d) none of the above
d) none of the above
