Studied by 1 personteeth: crown
visible portion
teeth: root
invisible portion, embedded in the dental alveolus
teeth: neck
between crown and root, near gum line
teeth: pulp cavity
hollow center within crown that is enclosed by dentin and filled with dental pulp
teeth: root canal
narrow extensions of pulp cavity that contain nerves and blood vessels, runs through root of tooth, has opening at base called apical foramen that vessels and nerves enter through, blood vessels nourish, lymphatic vessels offer protection, nerves provide sensation
how many teeth as child? what are they called?
20; deciduous
how many adult teeth? what are they called? what about molars?
32; permanent; not everyone gets all their molars
in conjunction with the __ , the teeth push food into a bolus via __
tongue; mastication
teeth: pulp
soft gel in pulp cavity, connective tissue containing blood/lymphatic vessels and nerves
teeth: dentin
hard matter that cover pulp, makes majority of internal tooth, gives tooth basic shape and rigidity, dentin hypersensitivity
teeth: enamel
covers dentin in crown, mainly calcium phosphate and calcium carbonate, hardest substance in body, protects tooth from wear/tear of chewing, protects against acids that can easily dissolve dentin,
teeth: cementum
covers dentin in root, attaches root to periodontal ligament
teeth: periodontal ligament
attaches root to alveolar process, acts as shock absorber during chewing
teeth: gingiva
gums, covers alveolar processes
teeth: incisors
single root, blade shaped, 4 front in top/bottom, biting teeth
teeth: cuspids/canines
single root, cone shaped, for tearing, posterior to incisors,
teeth: bicuspids/premolars
1 or 2 roots, flat crowns w ridges, for grinding
teeth: molars
3 or more roots, flat crowns w ridges, for grinding and crushing
tongue
move food for chewing, shape food into bolus, force food to back of mouth for swallowing, speech, taste, secretes mucus/lingual lipase
pairs of salivary glands
parotid, sublingual, submandibular
what do salivary glands do?
secrete saliva that softens/moistens/dissolves foods, cleanses mouth and teeth, initiates digestion of starch
what starts digesting starches?
salivary amylase
where are parotid salivary glands?
inferior and anterior to ears in cheeks
where are sublingual salivary glands?
under tongue
where are submandibular salivary glands?
under floor of mouth
parotid glands secrete what enzyme?
salivary amylase that stars digesting starches
what does saliva do?
lubricates and dissolves foods and begins chemical breakdown of carbohydrates and lipids
what is saliva made up of?
mostly water and solutes and enzymes like sodium, potassium, chloride, bicarbonate, and phosphate, lysozyme, salivary amylase
the order of the ducts, starting from right hepatic duct and ending at pancreatic duct
right and left hepatic ducts join to create the common hepatic duct which joins the cystic duct from gallbladder to form bile duct and the pancreatic duct joins it and enters duodenum
function of ingestion
taking food into mouth
function of processing
physically breaking down food substances into smaller particles to undergo chemical digestion more efficiently
function of digestion
mechanical and chemical breakdown of food
function of secretion
release of water, acid, buffers, enzymes into lumen of digestive canal
function of absorption
passage of digested products from digestive canal into blood plasma and lymph plasma
function of elimination
elimination of feces from digestive canal
function of visceral peritoneum
aka serosa, covers some organs in peritoneal cavity and is their serosa, portion of serosa covering stomach and at lesser curvature of stomach the visceral peritoneum extends up to liver as lesser momentum and at greater curvature of stomach continues down as greater omentum and drapes over intestines, gallbladder, small intestine, produces peritoneal fluid
function of parietal peritoneum
lines wall of abdominal cavity, produces peritoneal fluid
function of mesentery
fan shaped fold of peritoneum that binds jejunum and ileum of small intestine to posterior abdominal wall, suspend abdominal organs
function of lesser omentum
superior, stabilizes stomach, connects stomach and duodenum to liver
function of greater omentum
4 layers, inferior, attachments along stomach/duodenum and extends down anterior to small intestine and turns and extends up and attaches to transverse colon, supports intestines
function of mesocolon
2 separate folds of peritoneum that bind transverse colon and sigmoid colon of large intestine to posterior abdominal wall, with help of mesentery=lock organs into place
function of falciform ligament
stabilizes liver and attaches it to anterior abdominal wall and diaphragm, liver is only digestive organ attached to anterior abdominal wall
site of production/action, function, substrates, productions of SALIVARY AMYLASE
produced by salivary glands, acts in mouth, enzyme that starts breakdown of starches in mouth into smaller molecules like maltose/maltotriose/dextrins
site of production/action, function, substrates, productions of PANCREATIC AMYLASE
produced by pancreatic acing cells, acts in small intestine, enzyme that digests starch (substrate) in small intestine (duodenum) and breaks them down into maltose/maltotriose/dextrins
site of production/action, function, substrates, productions of PEPSIN
secreted by chief cells in stomach, acts in stomach, digests proteins, breaks peptide bonds between AAs and breaks protein chain of many AAs into smaller peptide fragments, substrates are proteins, products are peptides
site of production/action, function, substrates, productions of TRYPSIN
produced by pancreatic acinar cells, acts in small intestine (duodenum), acts on proteins (substrates) and produced peptides (products)
site of production/action, function, substrates, productions of PANCREATIC LIPASE
secreted by pancreas into small intestine (site of action), digests oils and fats (triglycerides as substrates), fatty acids/monoglycerides (products) from pancreatic acinar cells
explain hydrolysis reactions
during digestion, decomposition reactions break down large nutrient molecules into smaller molecules by addition of water molecules; enable dietary nutrients to be absorbed into body
list site of production, stimulus, target organs, and function of GASTRIN
produced by G cells of gastric glands, stimuli: distension of stomach by chyme/partially digested proteins in chyme/high ph of chyme due to presence of food in stomach/caffeine in gastric chyme/ach released from parasympathetic neurons (stimuli), stimulates gastric glands (target organ), stimulates gastric glands to secrete large amounts of gastric juice and increase gastric motility and promotes growth of gastric mucosa (function)
list site of production, stimulus, target organs, and function of GIP
secreted by small intestine (enteroendocrine cells) in response to presence of food (stimulus), stimulate release of insulin from pancreas to control blood glucose levels, targets pancreas, inhibits gastric secretion of absence of proteins
list site of production, stimulus, target organs, and function of SECRETIN
secreted by enteroendocrine cells in small intestine, stimulated by acidic chyme, causes buffering of acid in chyme that reaches duodenum and slows production of acid in stomach and inhibits secretion of gastric juice and promotes normal growth and maintenance of pancreas
list site of production, stimulus, target organs, and function of CHOLECYSTOKININ (CCK)
secreted by enteroendocrine cells in small intestine, stimulated by protein and fat, targets pancreas and gallbladder, stimulates secretion of pancreatic juice rich in digestive enzymes/causes ejection of bile from gallbladder/causes feeling full/inhibits gastric emptying/promotes normal growth and maintenance of pancreas/enhances effects of secretin
role of vagus nerve in digestion
from neck down to second segment of transverse colon, supplies motor parasympathetic fibers to all organs, stimulate gastric glands to secrete gastric juice, increase digestive canal secretion and motility by increasing activity of ENS neurons
role of submucosal plexus in digestion
in submucosa, derived from myenteric plexus, motor parasympathetic/sensory neurons, motor neurons supply secretory cells of mucosal epithelium which controls secretions of organs in digestive canal, regulates digestive canal secretion
role of myenteric plexus in digestion
between longitudinal and circular muscle layers, in esophagus/stomach/intestine, motor sympathetic/parasympathetic, controls digestive canal motility (movement) especially frequency and strength of contraction of muscular layer, regulates digestive canal motility
characteristics of cephalic phase of digestive activity
begins when see/smell/taste/think of food, uses PNS, lasts only minutes, stuff activates cerebral cortex/hypothalamus/brain stem then activates cranial nerves, purpose of phase is to prepare mouth and stomach for food that is about to be eaten
characteristics of gastric phase of digestive activity
begins with food entering stomach (distension/ph changes/undigested proteins), lasts 3-4 hrs, neural and hormone mechanisms regulate gastric phase to promote gastric secretion and gastric motility, hormone gastrin involved in this phase
characteristics of intestinal phase of digestive activity
begins when chyme and food enters small intestine, controls rate of gastric emptying, reflexes here have inhibitory effects that slow exit of chyme from stomach which prevents duodenum from being overloaded with more chyme that can handle, promote continued digestion of foods that have reached small intestine, activities of this phase regulate by neural and hormonal mechanisms, enterogastric reflex occurs, gastric motility inhibited and increase in contraction of pyloric sphincter which decreases gastric emptying, cholecystokinin and secretin
peristalsis
happens during esophageal stage, contractions of circular and longitudinal layers of muscular layer that push food bolus forward, circular muscles contract BEHIND bolus and relax AHEAD of bolus, longitudinal muscles contract AHEAD of bolus
segmentation
churning motions that break bolus with the help of chyme, mixes chyme with digestive juices and brings food into contact with mucosa for absorption
deglutition
aka swallowing, mechanism that moves food from mouth into stomach, 3 stages: buccal, pharyngeal, esophageal
buccal phase of deglutition (swallowing)
first phase, voluntary, bolus passed into oropharynx
pharyngeal phase of deglutition (swallowing)
second phase, involuntary, swallowing reflex controlled by medulla and pons, bolus moves through oropharynx and laryngopharynx and then into esophagus
esophageal phase of deglutition (swallowing)
third phase, involuntary, starts when bolus enters esophagus, peristalsis pushes bolus onward
mastication
aka chewing, food manipulated by tongue and ground by teeth and mixed with saliva, result is food that is soft/flexible/easily swallowed bolus, salivary amylase then begins digestion of starches and lingual lipase acts on triglycerides
bolus
food that was reduced to soft/flexible/easily swallowed mass by mastication
chyme
semifluid mixture of partly digested food and digestive secretions found in stomach and small intestine during digestion of a meal
catabolism
breakdown of organic molecules that released energy, exergonic: release more energy than consume
anabolism
build up of organic molecules, endergonic: consume more energy than produce, performs structural maintenance/repairs, supports growth, produces secretions, build nutrient reserves
metabolism
chemical reactions of the body and are 2 types: catabolism and anabolism
site of production and effects of INSULIN
released by pancreatic beta cells, inhibits lipolysis: lack accelerates pace of lipolysis, stimulate protein synthesis, stimulates active transport of AAs into body cells, increase activity of enzymes needed for anabolism and synthesis of storage molecules, decrease activity of enzymes needed for catabolic reactions, stimulates conversion of glucose to glycogen (glycogenesis) in liver/muscle cells, enhances synthesis of triglycerides in liver/adipose
site of production and effects of GLUCAGON
secreted from pancreatic alpha cells of pancreas, in response to low blood sugar, targets liver, causes increased release of glucose into bloodstream due to gluconeogenesis and glycogenolysis, stimulates glycogen breakdown
where does glycogenolysis happen and what hormones stimulate it? when?
Hepatocytes and skeletal muscle fibers; glucagon and epinephrine; between meals
lipolysis location and what stimulates it?
adipocytes; Epinephrine, norepinephrine, cortisol, insulinlike growth factors, thyroid hormones
what stimulates protein breakdown?
cortisol
gluconeogenesis, where and what stimulates it?
synthesis of glucose from noncarbohydrates; Hepatocytes and kidney cortex cells; glucagon and cortisol
site of production and effects of THYROXINE
from thyroid, thyroid hormones rise=bmr rises, increase bmr by stimulating cellular respiration (calorigenic effect)
site of production and effects of GROWTH HORMONE
from pituitary gland, increase appetite and decrease energy expenditure, increase metabolic rate
site of production and effects of EPINEPHRINE
from suprarenal medullae, enhance triglyceride breakdown into fatty acids and glycerol, stimulate glycogen breakdown, increase metabolic rate, increase appetite and decrease energy expenditure, increase metabolism which increases heat production, stimulates glycogenolysis
primary hormone in absorptive state
insulin
primary hormone during fasting/postabsorptive
glucagon
what is used during fasting/starvation?
fatty acids and ketone bodies for ATP production.
absorptive state
ingested nutrients are entering the bloodstream and glucose is readily available for ATP production
fasting/postabsorptive state
absorption of nutrients from the digestive canal is complete and energy needs must be met by fuels already in the body
absorption of 1 meal takes how many hours? how many hours a day does it consume?
4; 12
postabsorptive state takes up how much of a day?
12
what happens to the fasting/postabsorptive state if you skip meals?
extended
what happens during the absorptive state?
some of the absorbed nutrients are catabolized for the body’s energy needs or are used to synthesize proteins
walls of digestive system from inner to outer
mucosa, submucosa, muscularis, serosa
describe the mucosa
epithelial with glands and goblet cells
describe submucosa
loose connective tissue with blood vessels and lymph nodes
describe muscularis
2 muscle layers, inner is circular and outer is longitudinal
describe serosa
epithelial and secretes fluid to prevent friction
what is the peritoneum lined with?
serous membranes
what is bounded externally by lips (labia) and cheeks?
the mouth
what is lip color due to..
poor keratinization
function of the mouth
analyses and mechanically processes food, lubricates with secretions, begin digestion of carbohydrates
vestibule of mouth
space between lips/cheeks and teeth
fauces of mouth
where food enters oropharynx
Note
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