Digestion Flashcards
what is the crown?
the portion of the tooth above the gum line
what is the root?
the portion of the tooth below the gum line embedded in the alveoli below the gingiva
what is the dentin?
the largest component of a tooth, it lies under enamel and cementum
what is the cementum?
the thin, bone like covering over the roots of brachyodont teeth and most of the entire tooth superficial to the enamel of hypsodont teeth
what is the cemento-enamal junction?
where the enamel and cementum meet; a junction where the crown turns into the root
what is the periodontal ligament?
made of dense fibrous connective tissue that links cementum with the alveolar wall, anchoring the tooth into the jaw
what is stomatitis?
inflammation of the mouth that is not associated with the gingiva
what is gingivitis?
the most common dental disease; inflammation of the gingival membranes
what is the gingival sulcus?
the normal space between the gingiva and tooth;
what is periodontitis?
inflammation of the tissue around the teeth, the periodontium, often causing shrinkage of the gums and loosening of the teeth
what is the enamel?
it covers the crown of the tooth
what is the adult feline dental formula?
2 (I 3/3, C 1/1, PM 3/2, M 1/1) = 30
what is the deciduous feline dental formula?
2 (I 3/3, C 1/1, PM 3/2) = 26
what is the adult canine dental formula?
2 (I 3/3, C 1/1, PM 4/4, 2/3) = 42
what is the deciduous canine dental formula?
2 (I 3/3, C 1/1, PM 3/3) = 28
what is the adult equine dental formula?
2 (I 3/3, C 1(0)/1(0), PM 3(4)/3, M 3/3) = 38, 42, 44
what is the deciduous equine dental formula?
2 (I 3/3, C 1/1, PM 3/3) = 28
what is the adult porcine dental formula?
2 (I 3/3, C 1/1, PM 4/4, M 3/3) = 44
what is the deciduous porcine dental formula?
2 (I 3/3, C 1/1, PM 3/3) = 28
what is the adult ruminant dental formula?
2 (I 0/3, C 0/1, PM 3/3, M 3/3) = 32
what is the deciduous ruminant dental formula?
2 (I 0/4, C 0/0, P 3/3) = 20
what is heterodont dentition mean?
refers to teeth of differing shapes and sizes
what is hypsodont teeth?
teeth that grow continuously through out the life of an animal because of a large reserve of crown beneath the gingiva
what is brachyodont teeth?
teeth with relatively small crowns and well developed roots
what is radicular hypsodont?
the apices of the roots remain open for a significant part of an animal’s life, leading to continued growth, but do eventually close and stop growing
what is aradicular hyposdont?
these teeth lack a true root and grow continuously throughout the life of an animal
what is the neck?
where the crown and root meet
what is the apex?
the tip of the root of a tooth and is where the blood vessels and nerves enter the tooth
how many roots does a dog’s top jaw cheek teeth have?
the first premolar has 1 root, the 2nd premolar has 2 roots, the 3rd has 2 roots, and the 4th has 3 roots
what is the pulp?
the part of the tooth that contains blood and nerves
what are the fat soluble vitamins?
vitamins a, d, e, and k
what are the volatile fatty acids?
acetate, butyrate, and proprionate acids; acetate and butyrate are the fatty acids in milk and proprionate is especially important for cows
what are the hormones of the GI system?
gastrin, secretin, and cck
what are the hormones of the pancreas?
insulin and glucagon
what ways is the GI system stimulated?
neuronal, hormonal, and by enzymes
what are the 2 ways the GI system is stimulated neuronally?
by the CNS, including the long reflex of the ANS (acetylcholine) and the SNS (norepinephrine); and by the myenteric plexus
what kind of reflex is the CNS to the GI tract?
the signals have a long way to travel so it is a long reflex
what kind of reflex is the myenteric plexus to the GI tract?
there is a shorter distance of signals to travel so it is a short reflex
where is the myenteric plexus located?
between the mucosa and circular muscle layer of the GI tract and between the circular and longitudinal muscle layer of the GI tract
where is the most fat absorbed?
the small intestine
what area of the nervous system controls reticuloruminal activity?
the brainstem
which nervous system increases digestion?
the parasympathetic nervous system, by releasing acetoycholine
what is glucogenisis?
making sugar from non-sugar sources
what is ketosis?
the use of fatty acids during severe starvation, overwhelming the oxidative capacity of the liver in non-ruminants
where does most water absorption take place?
in the colon
what are two species that require microbial fermentation to digest their food?
any ruminant, horse or rabbit
what is the purpose of stratified squamous epithelium that lines much of the GI tract?
protection
how many layers of muscle make up the muscular layer of the wall of the intestines?
two: inner circular and outer longitudinal
what are the two nerve plexuses that make up the intrinsic enteric nervous system?
submucosal plexus (meissner’s plexus) and the myenteric plexus (auerbach’s plexus)
what does the endocrine hormone cholecystokinin (cck) do?
it inhibits gastric emptying
what does the endocrine hormone gastrin do?
it stimulates stomach motility
what are the two parts of the roof of the mouth?
hard palette and soft palette
what are the four types of teeth that make up heterodont dentition
incisors, canines, premolars and molars
the majority of the tongue is made up of what type of tissue?
muscle
what substances besides water are found in saliva?
protein, electrolytes, IgA, glycoproteins, bicarbonate, and enzymes
what are the three primary salivary glands in a dog?
parotid, sublingual, mandibular (zygomatic)
what does TMJ mean?
temporomandibular joint
when speaking of the movement of the mandible, what is translation?
movement to the side and forward
what is the structure that covers the opening of the trachea when an animal is swallowing food?
the epiglottis
what happens during prehension?
bringing food into the mouth
what happens during deglutination?
swallowing
what is mastication?
chewing
what phase of swallowing is under conscious control?
the first phase that takes food to the pharynx
what is peristalsis?
the pattern of muscular contractions and dilations that moves food forward through the esophagus and other parts of the digestive system
what is the visceral peritoneum?
the serous membrane that covers the organs of the abdominal cavity
what is the omentum?
the connecting peritoneum that links the stomach to the abdominal wall
what are the four sections of the monogastric stomach?
cardia, fundus, corpus (body), pylorus
what proteolytic enzyme in the stomach begins protein digestion?
pepsin
what three actions result from acetylcholine release during cephalic phase of gastric secretion?
parietal cells release HCl, chief cells secrete pepsinogen, G cells secrete gastrin
what is intrinsic factor?
secreted by parietal cells, it is necessary for absorption of B12 in the small intestine; except in the cat, the pancreas excretes the intrinsic factor
which neurotransmitter, released by sympathetic neurons, causes a reduction in the frequency of smooth muscle contractions in the stomach?
norepinephrine
what part of the monogastric stomach increases in size to accommodate a large meal?
the fundus
what nerve can elicit opposite types of gastric movement through the release of different neurotransmitters in the myenteric plexus?
vagus nerve
what are the two types of digestion that take place in the stomach?
mechanical and chemical
what do repeating units of monosaccharides make up?
carbohydrates
what are the four chambers of the ruminant stomach?
rumen, reticulum, omasum, and abomasum
which of the four chambers is the largest fermentation chamber and on which side of the animal would you look to see whether it was bloated?
the rumen on the left side
which chamber is known as the many plies?
the omasum
what is the importance of the esophageal groove?
it allows milk in a nursing ruminant to bypass the reticulorumen and go directly to the omasum; this prevents lactic acid buildup from fermentation in the reticulorumen.
what is eructation?
the process by which gas produced by the fermentation process is released from the reticulorumen and passed up the esophagus and into the trachea, where it is expelled during expiration
what does a cow do when she chews her cud?
rumination
what is rumination?
the process by which food is brought back to the oral cavity by antiperistalsis in the esophagus; the purpose is to chew the food more thoroughly and to add more saliva
what is the main source of energy in ruminants?
volatile fatty acids
how are complex carbohydrates broken down in the reticulorumen?
monosaccharides or polysaccharides
what are the three most important volatile fatty acids produced by conversion from pyruvate?
acetate, propionic acid, and butyric acid
what three compounds can be found as lipids in grasses and plants?
triglycerides, glycolipids, free fatty acids
where are proteins in ruminant diets broken down extracellularly by peptidase?
small peptide chains
where does urea produced as a by-product of amino acid metabolism in the ruminant liver go for reuse?
reticulorumen
what is gluconeogenesis and where in the ruminant does it mostly take place?
the production of glucose from noncarbohydrate sources, and it mostly takes place in the liver
what is the brush border in relation to the small intestine and what is its function?
the microvilli on the villi of epithelial cells lining the small intestine and they increase the surface area of the intestinal lumen resulting in a greater surface for absorption; they also contain enzymes necessary for membranous digestion
what characteristics of chyme are necessary to stimulate the release of CCK?
high amino acid or fatty acid content, low pH
which hormone, released in the duodenum, is responsible for decreased hydrochloric acid production in the stomach?
secretin
what substance, released by the pancreas and liver into the duodenum, helps neutralize the acidic chyme leaving the stomach?
bicarbinate
what substances are secreted by the exocrine portion of the pancreas?
lipase, amylase, nucleases, proteases, and proenzymes
what three structures are found in the triad located at the periphery of a hepatic lobule?
portal vein, hepatic artery, bile duct
what is the function of kupffer cells?
they are hepatic macrophages that engulf foreign substances
where does the common bile duct enter the small intestine
duodenum through the sphincter of Oddi
what common species of domestic animal does not have a gallbladder?
equine
what is enterohepatic circulation?
the pathway that bile salts take from the liver to the intestines, to the portal vein, and back to the liver. This circulation bypasses systemic circulation
unconjugated bilirubin in blood is not water soluble, so how does it become soluble?
it combines with the plasma protein albumin and is transported to the liver, where it is taken in by a hepatocyte; in the hepatocyte, it is conjugated with glucuronic acid and becomes water soluble
what is the major storage form of glucose?
glycogen
how are triglycerides in adipose tissue converted into glucose for energy?
lipase breaks down the triglyceride into glycerol and fatty acids that are transported to various tissues, including the liver.; in the liver glycerol is converted to glucose by gluconeogenesis; in other tissues the fatty acids are oxidized to produce energy
which plasma protein produced in the liver plays a crucial role in fluid movement between plasma and interstitial fluid?
albumin
which movement in the small intestine propels intestinal content toward the rectum?
peristalsis
in the luminal phase of chemical digestion, of starches, which enzyme, secreted by the pancreas, is needed?
amylase
in the membranous phase of chemical digestion of sugars, where are the necessary enzymes located?
embedded in the brush border of the intestinal epithelium
what is an exopeptidase?
an enzyme that breaks off amino acids at the end of a polypeptide chain
what does it mean when both glucose and amino acids are brought into a cell through secondary active transport?
the sodium-potassium pump is creating a concentration gradient that favors movement of sodium into a cell; glucose and amino acids can ride along with the sodium into the cell, even against a favorable concentration gradient
what are the four parts of the large intestine?
cecum, colon, rectum, and anus
what is a common species of animal that has a short ascending colon?
dog, cat, or any carnivore
what is the purpose of sacculations?
they prolong the time contents stay in the large intestine; they create extra volume; they allow for more time for absorption and microbial digestion
what are the four movements associated with the large intestine?
peristalsis, antiperistalsis, segmentation, and mass movement
how are feces formed?
water is removed from chyme
what species has a spiral shaped ascending colon?
pig
