Digestive System Flashcards
Consists of the degradation of large molecules into smaller molecules that can be absorbed into the bloodstream and used directly by cells
digestion
Digestion that occurs within the cell, usually in membrane bound vesicles
intracellular digestion
digestive process that occurs outside the cell, within a lumen or tract
extracellular digestion
The human digestive tractive begins with the __ ___ and continues with the ___, ___, ___, ___ ___, __ ___ and ____.
oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, anus.
Accessory organs such as ____ glands, ___, ____, and ___ also play essential roles in digestion
salivary, pancreas, liver, gallbladder
The oral cavity is where ____ and ___ digestion of food begins. The former is the breakdown of large food particles into smaller particles through __ ___ such as the __ and __ action of teeth (mastication), or the ___ ___ of the stomach. The latter refers to the ____ ____ of macromolecules into smaller molecules. It begins when the salivary glands secrete _____, which ___ food to facilitate swallowing and provides a ___ for food particles.
physical, chemical, physical actions, chewing, biting, churning motion, enzymatic breakdown, saliva, lubricates, solvent
Saliva is secreted in response to food in the __ ___. It contains the enzyme __ ___ (___) which hydrolyzes ___ to ____ (a disaccharide). Food that has been moistened and chewed enough to be swallowed is called a ____
oral cavity, salivary amylase, ptyalin, starch, maltose, bolus
A muscular tube leading from the mouth to the stomach
esophagus
Food is moved down the esophagus by __ ___ of ____ muscular contractions called ____. The esophagus is closed off from the stomach by contraction of a muscular structure called the ___ ____ (___) ____.
rhythmic waves, involuntary, peristalsis, lower esophageal, cardiac, sphincter
The body of the esophagus lies within the __ ___, which is ____ pressured relative to the environment on inhalation. The __ ____ has relative positive pressure. Therefore, without normal defence mechanisms, the pressure gradients favor a continual reflux of ____ materials into the ____, resulting in a pathological condition known as _____ ___ ____ (GERD).
thoracic cavity, negative, adominal cavity, gastric, esophagus, gastroesophageal reflux disease
GERD can result in: reflux occurring after ____ ____ lower esophageal ____ ____ not associated with swallowing, a decreased lower esophageal sphincter ____, and an increased passage of __ ___ into the esophagus
spontaneous transient, sphincter relaxations, pressure, stomach contents
The stomach, a large, muscular organ located in the upper ___, stores and ___ digests food. The walls of the stomach are lined by the __ ___, a mucous membrane that contains the __ ___. Mucous cells in ____ ___ along the membrane secrete mucus to protect the stomach ____ from the harshly ___ juices present in the stomach (ph = __).
abdomen, partially, gastric mucosa, gastric glands, gastric pits, lining, acidic, 2
Chief cells found within the gastric glands synthesize ____, which is converted into ___ upon contact with stomach acid and breaks down ____.
pepsinogen, pepsin, proteins
___ ____ also present within gastric glands, synthesize and release ____, which alters the pH of the stomach and kills ____, and __ ___, which is necessary for the absorption of ____ ___.
parietal cells, HCl, bacteria, intrinsic factor, vitamin B12
The ___ of the stomach combined with its enzymatic activity, produces an ___, ____ mixture of partially digested food known as ____.
churning, acidic, semifluid, chyme
Chyme passes into the first segment of the small intestine called the ___, through the __ ____. __ ___ is completed in the small intestine.
duodenum, pyloric sphincter, chemical digestion
The three sections of the small intestine
duodenum, jejunum, ileum
The small intestine is highly adapted to ____. To maximize the __ ____ available for digestion and absorption, the intestine is extremely ____, greater than ___ m in length, and highly ___. In addition, numerous ____ _____ called ____ extend out of the intestinal wall. These contain ___ and _____, and ____ __ and ____ pass through their walls into the capillary system.
absorption, surface area, long, 6, coiled, finger-like projections, villi, capillaries, lacteals, amino acids, monosaccharides
Blood from the digestive tract enters the __ ___ of the liver, where it is ____ and stripped of some of its ____.
portal system, detoxified, nutrients
Large ___ ___ and ___ pass into the lacteals and are then reconverted into _____ in the ____.
fatty acids, glycerol, triglycerides, liver
Some nutrients such as ___ and __ ___, are actively absorbed and require energy. Other nutrients are ___ absorbed
glucose, amino acids, passively
Most digestion in the small intestine occurs in the _____, where secretions of the intestinal ___, ___, __ and ____ mix together with the acidic chyme entering from the stomach. The intestinal mucosa secretes ______ (for fat digestion), _____ (for polypeptide digestion), and _____ (for maltose, lactose, sucrose digestion).
duodenum, glands, pancreas, liver, gallbladder, lipases, aminopeptides, disaccharidases
The disaccaridase ______, breaks down _____ (milk sugar). This enzyme is present in most ___, but many adults lack the enzyme are thus the milk sugar is instead broken down by ____ promoting large quantities of __ and resulting in intestinal discomfort
lactase, lactose, infants, bacteria, gas
____ is a hormone produced in the __ cells of the duodenum. It primarily functions to stimulate __ and ___ secretion as well as increase gastric ___ ___. This also stimulates the ___ cells to produce HCl, which ___ proteins and activates digestive enzymes
gastrin, g, histamine, pepsinogen, blood flow, parietal, denatures
__ ____ is secreted by parietal cells, and facilitates the absorption of ___ ___ across the intestinal lining.
intrinsic factor, vitamin b12
______ (CCK) is produced and stored in the ___ cells of the duodenal and ____ mucosa. It is involved in stimulation of ___ ___ and ____ secretion, as well as ___ contraction. It also acts as a hunger ____.
cholecystokinin, i, jejunal, pancreatic enzyme, somatostatin, gallbladder, suppressant
____ is synthesized and stored in the ___ cells of the upper intestine. It stimulates the secretion of __ substances from the pancreas, and inhibits __ __ and ___ __ production
secretin, S, bicarbonate-containing, gastric emptying, gastric acid
The liver produces ___ that is stored in the ___ before being released into the small intestine. This substance contains no ____. It emulsifies ____, breaking down large globules into small droplets. This exposes a greater surface area of the fat to the action of __ ___. In the absence of this, fats cannot be ___.
bile, gallbladder, enzymes, fats, pancreatic lipase, digested
The liver’s functions also include storage of ____, conversion of ammonia to ___, ___ synthesis, ___ and ___ metabolism
glycogen, urea, protein, detoxification, cholesterol
The pancreas produces enzymes such as ___ for carbohydrate digestion, and ___ for protein digestion, and ___ for fat digestion.
amylase, trypsin, lipase
When the pancreas releases ___ and ____, the latter cleave ___ to ___. This then cleaves and activates the other ____ (enzyme precursors)
chymotrypsin, enterokinase, trypsinogen, trypsin, zymogens
The pancreas secretes a _____ juice that neutralizes the acidic chyme. The pancreatic enzymes operate optimally at this ____ pH
bicarbonate-rich, higher
The large intestine is approximately ___m long and absorbs ____ and any ____ not already absorbed by the small intestine.
1.5, salts, water
The ___ provides a transient storage of feces before elimination through the ____
rectum, anus
