Digestive System Flashcards
In the enteric nervous system, and long reflexive pathway bandage over a short reflexive pathway in the fact that…
Long reflexive pathways can be stimulated by things outside of the G.I. tract
The bolus is liquefied in the… And is now called chyme
Stomach
Stellar macrophages are found in the liver and are responsible for removing bacteria and worn-out cells. True or false
True
Fats significantly delay the emptying of the stomach through hormonal and neuronal signals.
True
Hepatocytes do not…
Produce digestive enzymes
Which of the following are types of papillae on the tongue that contain taste buds
Fungiform and circumvallate
It is important to ensure that your diet is adequately rich in vitamins because…
Most vitamins are coenzymes needed to help the body utilize essential nutrients
Except for lactose and some glycogen, the carbohydrates we can just remain we remotes. True or false
False
The molecule that serves as the major source of readily available fuel for neurons and blood cells is…
Glucose
Select the correct statement about proteins: Catabolic steroids or hormones accelerate the rate of protein synthesis; strict vegetarians need not worry about adequate protein intake as most vegetables are almost perfect sources of amino acids; proteins will be used by most cells for ATP synthesis if insufficient carbs are ingested; all proteins can be synthesized in the body is most of the amino acids are present
PROTEINS WILL BE USED BY MOST CELLS FOR ATP SYNTHESIS IF INSUFFICIENT CARBS ARE INGESTED;
The process of breaking triglycerides down into glycerol and fatty acid is known as…
Lipolysis
Which of the following is the best illustration of the difference between metabolism digestion?
Metabolism comprises all of the chemical reactions performed within the body while digestion is only the breakdown of food within the G.I. tract
The most abundant dietary lipids are…
Triglycerides
RBCs lack mitochondria. As a result, ATP production is solely through..
Glycolysis
Oxidation reduction reactions…
May involve the loss of hydrogen and electrons
Wavelike smooth muscle contractions that move foodstuffs through the alimentary tube.
peristalsis
Chemical or mechanical process of breaking down foodstuffs into simpler units.
Digestion
Enzymatic breakdown of any type of food molecule.
Hydrolysis
Process by which simpler chemical units pass through the lumen of the gastrointestinal tract into the blood or lymph.
Absorption
Increases output of enzymatic-rich pancreatic juice.
Cholecystokinin
Increases output of pancreatic juice rich in bicarbonate ions.
Secretin
Increases HCl secretion and stimulates contraction of intestinal muscle.
Gastrin
Stimulates insulin release and mildly inhibits HCl production.
Gastric inhibitory peptide
Synthesis of lipids from glucose or amino acids.
lipogenesis
Splitting of triglycerides into glycerol and fatty acids.
lypolysis
Conversion of fatty acids into acetyl groups.
beta oxidation
Formation of ketone bodies.
ketogenesis
Breakdown of glycogen to release glucose.
glycogenolysis
Formation of glucose from proteins or fats.
gluconeogenesis
Storage of glucose in the form of glycogen.
glycogenesis
Breakdown of glucose to pyruvic acid.
glycolysis
Heat transfer into the chair you are sitting on.
Conduction
Heat exchange when you are under a ceiling fan.
Convection
Heat loss in the form of infrared waves.
Radiation
Heat loss during sweating.
evaporation
The peritoneal cavity…
like the pleural and pericardial cavities is a potential space containing serous fluid
Obstruction of the hepatopancreatic sphincter impairs digestion by reducing the availability of…
pancreatic juice and bile
The lamina propria forms part of the _____.
mucosa
Carbohydrates are acted on by …
amylase, maltase, and sucrase
The parasympathetic nervous system influences digestion by ….
stimulation peristalsis and secretory activity
The digestive juice product containing enzymes capable of digesting all four major foodstuff categories is ____.
pancreatic
The vitamin associated with calcium absorption is ____.
D
Someone has eaten a meal of buttered toast, cream, and eggs. Which of the following would you expect to happen? a) Compared to the period shortly after the meal, gastric motility and secretion of HCl decrease when the food reaches the duodenum; b) gastric motility increases even as the person is chewing the food (before swallowing); c) fat will be emulsified in the duodenum by the action of bile; d) all of these.
d) all of these
The gallbladder ….
stores and concentrates bile
The sphincter between the stomach and duodenum is…
pyloric sphincter
A protein molecule will be digested by enzymes made by the …
pancreas, stomach, and small intestine
A protein molecule must be digested before it can be transported to and utilized by the cells because….
The protein is too large to be readily absorbed
The products of protein digestion enter the bloodstream largely through cells lining…
the small intestine
Before the blood carrying the products of protein digestion reaches the heart, it first passes through capillary networks in ….
the liver
Having passed through the regulatory organ selected above, the products of protein digestion are circulated throughout the body. they will enter individual body cells by …
active transport
What are the alimentary canal organs of the digestive system?
mouth, pharynx, esophagus, stomach, small and large intestines
What are the accessory digestive system organs?
teeth, tongue, salivary glands, liver, gallbladder, and pancreas
What 6 major processes occur during digestive system activity?
ingestion (food intake); propulsion (movement of food through the tract); mechanical breakdown (processes that physically mix or break foods down into smaller fragments); digestion (food breakdown by enzymatic action); absorption (transport of products of digestion through the intestinal mucosa into the blood); and defecation (elimination of the undigested residues [feces] from the body)
The GI tract has ___ layers and is usually surrounded by ____.
4; peritoneum
The parietal and visceral layers of the peritoneum are continuous with one another via what extensions?
mesenteries, falciform, ligament, lesser and greater omenta
What is the basic pattern of tissue layers in the walls of all GI tract organs?
mucosa, submucosa, muscularis externa, and serosa (or adventitia)
Intrinsic nerve plexuses (enteric nerve system) are found…
within the walls of GI tract organs
The digestive viscera are served by the ______ circulation, consisting of _______ branches of the _____ trunk and ____ and ____ _____ circulation.
splanchnic; arterial; celiac; aorta; hepatic portal
What is the name of the GI tract nervous system?
enteric nervous system
The digestive system controls the environment within its _____ to ensure optimal conditions for _____ and _____ of foodstuffs.
lumen; digestion; absorption
Receptors and hormone-secreting cells of the alimentary canal wall respond to _____ and _____ that result in stimulation or inhibition of GI secretory activity or motility?
stretch; chemical signals
Food enters the GI tract via the mouth, which is continuous with the _____ posteriorly.
oropharynx
Te oral mucosa is _____ _____ epithelium, an adaption seen where abrasion occurs
stratified squamous
What accessory digestive organ is mucosa-covered skeletal muscle?
the tongue
The tongue’s _____ muscles allow it to change shape; its ____ muscles allow it to change position.
intrinsic; extrinsic
What are the three major salivary glands that produce saliva?
parotid, submandibular, and sublingual
What are the main components of saliva?
water, ions, proteins, metabolic wastes, lysozyme, defenses, IgA, salivary amylase, and mucin
What are the functions of saliva?
1) moistens and cleanses the mouth; 2) moistens foods, aiding their compaction; 3)dissolves food chemicals to allow for taste; 4) begins digestion of starch (salivary amylase)
What factors activate the production of saliva?
chemical and pressure receptors in the mouth and by the sight or smell of food
Which nervous system activates saliva production? Inhibits it?
parasympathetic; sympathetic
What are the four classes of teeth?
incisors, canines, premolars, and molars
What is the bulk of the tooth?
dentin, which surrounds the central pulp cavity
What secures the tooth to the bony alveolus?
a periodontal ligament
The ___ and ___ move food from the mouth to the stomach.
pharynx; esophagus
Food passes through the oropharynx to the —-
LARYNGOPHARYNX
The laryngopharynx joins the stomach at the ____ ____.
cardial orifice
The cardinal orifice is surrounded by the ____ sphincter.
gastroesophageal
The esophageal _____ is stratified squamous epithelium; its ____ is skeletal muscle superiorly and changes to _____ muscle inferiorly; It has a/an _____ rather than a/an ____.
mucosa; muscularis; smooth; adventitia; serosa
The pharynx and the esophagus are mainly food conduits that move food to the stomach by _____.
peristalsis
In the buccal phase, swallowing is initiated by the mouth after the bolus has been compacted. True or false?
True
Which phase is controlled reflexively by the swallowing center in the medulla and pons?
The pharyngeal-esophageal phase
When the peristaltic wave approaches the gastroesophageal sphincter, the sphincter …..
relaxes to allow food to enter the stomach
The stomach lies in the ____ ____ quadrant of the abdomen.
upper left
What are the stomach’s major regions?
cardia, fundus, body, and phyloric part
When empty, the stomach’s internal surface exhibits ____.
rugae
What layer of the stomach allows it to churn and mix food?
A third oblique layer of smooth muscle
What type of cells line the stomach mucosa?
simple columnar epithelium
Name the secretory cells contained in the gastric glands.
pepsinogen-producing chief cells; parietal cells, which secrete hydrochloric acid and intrinsic factor; mucous neck cells, which produce mucus; and enteroendocrine cells, which secrete hormones and paracrines
What characteristics protect the stomach from self-digestion?
The mucosal cells are connected by tight junctions, secrete a thick mucus, and are quickly replaced when damaged
What factors control gastric secretory activity in the stomach?
Nervous and hormonal factors
What are the three phases of gastric secretion?
cephalic, gastric, and intestinal
Mechanical breakdown in the stomach is triggered by….
stomach distension and coupled to food propulsion and stomach emptying
What cells in the small intestine set the rate of peristalsis?
pacemaker cells in the smooth muscle
What two factors control food movement in the duodenum?
pylorus and feedback signals
What is the lobed organ overlapping the stomach?
the liver
What are the structural and functional units of the liver?
the liver lobules
Blood flows into the sinusoids of the liver via the ____ and____.
hepatic artery proper; hepatic portal vein
What happens in the sinusoids of the liver?
macrophages remove debris and hepatocytes remove nutrients
Name three functions of hepatocytes other than removal of nutrients.
store glucose as glycogen; use amino acids to make plasma proteins; detoxify metabolic wastes and drugs
Bile is made continually by ….
hepatocytes
What stimulates bile production?
Bile salts and secretin
Bile contains….
electrolytes, various fatty substances, bile salts, and bile pigments
Bile salts are…
emulsifying agents that disperse fats and form water-soluble micelles, which solubilize the products of fat digestion
Where is the pancreas?
retroperitoneal between the spleen and small intestine
What exocrine product does the pancreas secrete?
pancreatic juice that is carried to the duodenum via the pancreatic duct
the pancreatic duct and the bile duct join to form the …
hepatopancreatic ampulla, which empty their secretions into the duodenum through the hepatopancreatic sphincter
Pancreatic juice is…
a HCO3- rich fluid containing enzymes that digest all categories of foods
What controls the secretion of pancreatic juice?
Intestinal hormones and vagus nerves
What is cholecystokinin and where is it released?
released by the small intestine, it stimulates the gallbladder to contract and the hepatopancreatic sphincter to relax, allowing bile (and pancreatic juice) to enter the duodenum
The small intestine is the major site for ___ and ___
digestion; absorption
What 3 components increase the intestinal surface area for digestion and absorption?
circular folds, villi, and microvilli
the duodenal submucosa contains …
elaborate mucus-secreting duodenal glands
Where are Peyer’s patches specifically locates?
in the mucosa of the ileum
The duodenum is covered with serosa. True or false?
False, adventitia
Intestinal juice is largely ….
water with mucus
The major stimuli for intestinal juice release are…
hypertonic and acidic chyme
What is the principal motility pattern of the small intestine?
segmentation
segmentation promotes…
mechanical breakdown and mixing of chyme with digestive juices and bile
segmentation and short-distance peristalsis causes….
slow propulsion
Ileocecal valve opening is controlled by…
the gastroileal reflex and gastrin
What are the subdivisions of the large intestine?
cecum (and appendix), colon (ascending, transverse, descending, and sigmoid portion), rectum, and anal canal
What is the main purpose of the large intestine?
to absorb water, some electrolytes and vitamins made by enteric bacteria, and to eliminate feces
What is the teniae coli?
the longitudinal muscle in the muscularis of the large intestine that is reduced to three bands, puckers its walls, and produces haustra
Describe the cells of the mucosa of most of the large intestine.
simple columnar epithelium containing abundant goblet cells
When is the defecation reflex triggered?
when feces enters the rectum
What does the defecation reflex involve?
The parasympathetic reflexes leading to contraction of the rectal walls and is aided by Valsalva’s maneuver
Digestion is accomplished by ___ and catalyzed by ___.
hydrolysis, enzymes
Most nutrients are absorbed by what type of process?
Active transport processes
Where are virtually all the foodstuffs and most of the water and electrolytes absorbed?
small intestine
How are carbohydrates and proteins processed?
digested to monomers and taken up into absorptive epithelial cells of the small intestine by cotransport with sodium, and passively transported across the basolateral membrane into the capillaries
How are fats processed?
Fat breakdown products are emulsified for digestion, then solubilized by bile salts (in micelles), resynthesized to triglycerides in the intestinal mucosal cells, and combine with other lipids and protein as chylomicrons that enter the lacteals
How are nucleic acids processed?
they are digested into their components and actively transported into absorptive epithelial cells
How are fat-soluble vitamins absorbed?
by diffusion
How are water-soluble vitamins absorbed?
by active or passive transport
How are absorbed substances, other than fat, delivered?
they enter the villus blood capillaries and are transported to the liver via the hepatic portal vein
The mucosa of the alimentary canal develops from which primary germ layer?
endoderm, which folds to form a tube
Other than the mucosa, the remaining three tunics of the alimentary canal wall are formed by what primary germ layer?
mesoderm
The glandular accessary organs (salivary glands, liver, pnacreas, and gallbladder) form from …
outpocketings of the mucosa
What are some congenital abnormalities of the digestive tract?
cleft palate/lip, tracheoesophageal fistula, and cystic fibrosis, which all interfere with normal nutrition
What reaction liberates the most energy?
complete oxidation of a molecule of sucrose to CO2 and water
The net gain of ATP from the complete metabolism (aerobic) of glucose is closest to …
30
Define cellular respiration.
oxidation of substances by which energy is released in usable form to the cells
What is formed during aerobic respiration when electrons are passed down the electron transport chain?
water
Metabolic rate is relatively low in ….
old age
In a temperate climate under ordinary conditions, the great loss of body heat occurs through…
radiation
Which of the following is not a function of the liver? a) glycogenolysis and gluconeogenesis, b) synthesis of cholesterol, c) detoxification of alcohol and drugs, d)synthesis of glucagon, e) deamination of amino acids
synthesis of glucagon; it is formed in the pancreas and promotes the breakdown of glycogen to glucose in the liver.
Amino acids are essential and important to the body for all the following except a) production of some hormones, b) production of antibodies, c) formation of most structural materials, d) as a source of quick energy
as a source of quick energy (that is glucose)
Transamination is a chemical process by which…
an amine group is transferred from an amino acid to a keto acid
Three days after removing the pancreas from an animal, the researcher finds a persistent increase in …
acetoacetic acid concentration in the blood, urine volume, and blood glucose
Body temperature regulation is influenced by and subject to what three factors?
influenced by temperature receptors in the skin, influenced by the temperature of the blood perfusing the heat regulation center of the brain, and is subject to both neural and hormonal control
