Digestive system review

hepatic ducts, common, cystic, bile duct

- Bile flows out of the liver through the right and left ___________ ______________ which come together to form the _______________ hepatic duct. This duct then joins with a duct connected to the gallbladder, called the _______________duct, to form the common ___________ ____________

store, defecation, contract, relax

- Distal large intestine: performs a small amount of absorption, primarily of water, but its main role is to ______________ fecal material until it is ready to be expelled during defecation o Less motile than proximal large intestine o When mass movements force fecal material into normally empty rectum, it initiates parasympathetic-mediated ______________ reflex: - Stretch receptors transmit sensation of rectal distention to spinal cord - Parasympathetic neurons cause smooth muscle in sigmoid colon and rectum to ____________, and internal anal sphincter to ______________ - Impulses from cerebral cortex trigger relaxation of external anal sphincter and contraction of levator ani muscle

Bilirubin, stercobilin, bile

- Liver excretes _________________; a waste product that results from breakdown of hemoglobin by spleen o Hepatocytes secrete bilirubin into bile and normal flora in large intestine convert it to urobilinogen then into stercobilin - _______________ is responsible for characteristic brown color of feces o Some urobilinogen is reabsorbed by large intestine and ends up back in hepatic portal system; so most urobilinogen is re-secreted into ___________ o Some remains in blood and is excreted by kidneys (note that yellow urobilinogen is largely responsible for color of urine)

nontoxic

- Liver has one of the most diverse sets of functions of any organ in body - Releases both endocrine and exocrine secretions - Converts harmful chemicals into __________ substances that the body can eliminated

bile, lipids, kidneys,

- Main digestive function of the liver is to produce _____________ o A liquid that contains multiple components, including water, electrolytes and organic compounds o Bile serves 2 critical functions - Required for digestion and absorption of _______________ - Provides a mechanism by which liver excretes wastes and other substances that _______________ cannot excrete

Swallowing, churning, peristalsis, defecation

- Movement of alimentary canal is a key process in every region of canal - Motility takes several form including: - ________________ - ______________ - __________________ - _________________ - some of these movements propel food through the canal whereas others mix it as part of mechanical digestion

Pancreatic juice, bicarbonate, catalyze, rises, Cholecystokinin, secretin

- collective secretions of pancreatic acinar and duct cells; consists of water and multiple digestive enzymes and other proteins o Duct cells also secrete ________________ ions, a base, which makes pancreatic juice alkaline o Alkaline juice helps neutralize acidic chyme that enters duodenum from stomach; protects duodenum from damage by acid o Its digestive enzymes, secreted by acinar cells, are crucial in chemical digestion; __________________ reactions that digest carbohydrates, proteins, lipids and nucleic acids o Pancreatic secretion occurs at a basal rate between meals o During eating, pancreatic secretion ______________ due to parasympathetic and hormonal stimulation: - One hormonal mediator of pancreatic secretion is _____________________ (CCK) · Produced by duodenal enteroendocrine cells in response to presence of lipids and partially digested proteins in duodenum · Acts on pancreatic acinar cells to trigger secretion of digestive enzymes and other proteins - Another stimulatory hormone is ______________ · Released by duodenal cells in response to acid and lipids in duodenum · Secretin primarily triggers duct cells and pancreas to secrete bicarbonate ions

Lesser omentum

- smaller mesentery - extends from medial surface of stomach to liver

voluntary, pharyngeal, Esophageal

3 phases of swallowing 1) ________________ phase: tongue pushes bolus posteriorly toward oropharynx a. Voluntary 2) ______________ phase: bolus enters oropharynx; soft palate and epiglottis seal off nasopharynx and larynx, respectively a. Involuntary 3) Esophageal phase: peristaltic waves move bolus down esophagus to stomach a. Involuntary

secondary, higher, against, into, glucose, galactose, fructose, protein

Absorption of Carbohydrates - Both glucose and galactose are transported across the enterocyte's apical membrane by the same ________________ active transport mechanism = Na+/glucose Cotransporter o Secondary active transport is a form of membrane transport in which ATP is used indirectly to move a molecule across membrane o Concentrations of glucose and galactose are _____________ in enterocyte's cytosol than they are in lumen of small intestine. o Absorption of glucose and galactose requires these molecules to move _____________their concentration gradients; this requires an input of energy provided by Na/Glucose cotransporter - Na+/k+ pump consumes ATP to drive sodium ions out of the enterocyte and into the lumen of the small intestine - This creates a concentration gradient that favors the movement of sodium ions back __________ the enterocyte o Concentration gradient is a form of potential energy - A cell harnesses this energy by allowing sodium ions to diffuse back into enterocyte, and this energy is used to drive the transport of _____________ and _____________ into the enterocyte o __________________ is unable to bind to Na+/Glucose cotransporter, so it crosses apical enterocyte membrane by a separate mechanism = facilitated diffusion - Fructose binds to a channel _________________ that mediates its facilitated diffusion across membrane - Facilitated diffusion is a passive process and requires no net input energy; this means that a concentration gradient MUST be present or fructose will not be absorbed

large, osmosis, lumen, cotransport, electrical

Absorption of water, electrolytes, and vitamins - Alimentary canal absorbs large quantities of water, electrolytes and vitamins o Much of this absorption occurs in small intestine, but a significant quantity occurs in ____________ intestine too - On average, over 9 liters of water are ingested, remaining 7 liters are secreted into alimentary canal by alimentary canal itself and accessory organs o OF the 9 liters, about 8 liters are absorbed into enterocytes of small intestine o Most of remaining water is absorbed into enterocytes of large intestine, leaving only about 0.1 liter of water to be excreted in feces o Water absorption occurs exclusively by _____________; requires a concentration gradient o Both cytosol of enterocytes and extracellular fluid in villi must be more concentrated than fluid in _____________ of intestine to drive water movement o Anything that causes excess solutes to remain in lumen of intestines will hold onto water and Prevent its reabsorption - Electrolytes are both taken in from diet and present in secretions from digestive organs o Most of these electrolytes are absorbed in small intestine, although significant amounts are absorbed in large intestine as well o An important mechanism for absorption of sodium ions revolves around __________________ of monosaccharides and amino acids o This sodium ion absorption is also key in absorption of anions- as sodium ions enter enterocytes, an ________________ gradient is created that drives absorption of anions such as chloride and bicarbonate ions o Other electrolytes have specialized mechanisms for their absorption; certain electrolytes that are present in smaller amounts, such as iron and magnesium ions, are absorbed by active transport mechanisms

facilitated, hepatic portal vein

All 3 monosaccharides cross the basal enterocyte membrane by the same ______________ diffusion - This process involves a membrane protein that is very similar to one that helps fructose cross the apical enterocyte membrane - After monosaccharides cross the basal membrane, the diffuse through extracellular fluid and into the capillaries in the villus - Once in blood, they are delivered to the liver via the ___________ ____________ _______________ for processing

Produce vitamins, Metabolize, harmful bacteria, immune system

Bacteria in large intestine: - These good bacteria called your normal flora consist of about 500 different bacterial species that coexist with humans in a symbiotic (mutual beneficial) relationship - Humans provide bacteria with the environment they need to survive; bacteria perform several useful functions for humans, including: 1) ______________ _______________: bacteria produce vitamins such as vitamin K, which is necessary for blood clotting 2) ______________ undigested materials: bacteria metabolize carbohydrates such as soluble fibers that small intestine is unable to digest, converting them into fatty acids and other molecules body can absorb and use o Deter growth of __________ _________________: - normal flora prevent growth of pathogenic (disease-causing) microorganisms by competing for nutrients and producing chemicals that kill certain harmful bacterial species o Stimulate ______________ _____________ - during infancy, normal flora induces immune tolerance to their own antigens; at same time, they stimulate development of mucosa-associated lymphoid tissue (MALT) and production of antibodies to pathogens

acinar cells, serous, mucous

Basic secretory cell of salivary glands is __________ __________ - two main types of acinar cells in salivary glands 1) _______________ cells: secrete a water-based fluid with enzymes and other solutes - Secretions are involved in digestive processes; generally released just before or during eating 2) ________________ cells: secrete mucus continually - Primarily involved in keeping oral mucosa moist

salivary amylase, inactivates, small intestine, brush border, lactose, monosaccharides

Carbohydrate digestion: - Digestion begins in mouth with help of _______________ _________________ from salivary glands; catalyzes reactions that break long polysaccharides into shorter oligosaccharides: o Generally accomplishes little actual chemical digestion because food simply is not in mouth long enough for it to have much effect o Salivary amylase digestion soon stops in the stomach, as stomach acid generally _______________ this enzyme before it can complete its taste o Chemical digestion of carbohydrates resumes in the ____________ _____________, where polysaccharides and oligosaccharides encounter pancreatic amylase o Oligosaccharide digestion is completed by reactions catalyzed by enzymes that are produced by the _________ _____________ of enterocytes, including the enzymes, lactase, maltase, and surcrase o Lactase only catalyzes the digestion of the sugar _____________ (found in milk and milk-based products) into glucose and galactose o Both maltase and surcase catalyze reactions that break oligosaccharides into disaccharides and ________________ o Result of the activity of these enzymes is the production of monosaccharides: glucose, fructose, and galactose - After carbohydrates have been digested into monosaccharides, they are ready to be absorbed

proximal large intestine

Consists of ascending and transverse colon (proximal or distal large intestine?)

stomach, polypeptides, small intestine, autodigestion, trypsin, free, cytoplasm

Digestion of proteins: - Chemical digestion of proteins does not begin until they reach _____________, where they encounter enzyme pepsin - Chief cells of gastric glands produce inactive precursor pepsinogen - Pepsinogen requires a pH of about 2 to become pepsin, and pepsin is inactivated completely at a pH of 7 - Activated pepsin catalyzes reactions that digest proteins into smaller __________________, oligopeptides, and some free amino acids - Pepsin reactions catalyze only about 10-15% of protein in ingested food - Majority of protein digestion takes place in _____________ ________________ with help of pancreatic enzymes and brush border enzymes o Five pancreatic enzymes digest proteins, all of which are released as inactive precursors - Inactive precursors protect pancreas from _______________, digestion of its cells by its own enzymes - First pancreatic enzyme to become activated is precursor trypsinogen; becomes active enzyme _________________ when it encounters enzymes on intestinal brush border · Trypsin catalyzes reactions that convert other pancreatic enzymes to their active forms, and activates additional trypsinogen as it is secreted by pancreas - These enzymes catalyze reactions that digest proteins and polypeptides into oligopeptides and some ______________ amino acids o Final enzymes to act on proteins are associated with enterocytes; there are multiple brush border enzymes that catalyze digestion of oligopeptides into free amino acids - These enzymes are limited in reactions they can catalyze, so some small oligopeptides (two to three amino acids long) remain undigested - These small oligopeptides are taken up by enterocytes · In enterocyte __________________ they encounter more enzymes that catalyze their breakdown into free amino acids

Upper esophageal, gastroesophageal, propulsion, secretion

Esophagus: - - At junction of pharynx and esophagus, there is a sphincter called ________________ ___________________ sphincter; controls passage of bolus into esophagus - - At esophagus' inferior end is another sphincter, ____________________ sphincter, also known as lower esophageal sphincter; regulates passage of bolus into stomach; also prevents contents of stomach from re-entering esophagus - Primary functions of esophagus are ________________ and a small amount of _____________ of mostly mucus

cleansing, lysozyme, mechanical, chemical

Functions of saliva: - Moistening, lubricating, and ___________________ oral mucosa - protection- _______________ and IgA deter growth of pathogenic bacteria in oral cavity - ___________________ digestion: achieved by moistening and helping to mix ingested food into a bolus so it can be swallowed - __________________ digestion: achieved by actions of salivary amylase - Taste: - Many food molecules dissolve in water of saliva, and these molecules then stimulate taste receptors on tongue

lacks, not, goblet, haustra

Histology of large intestine: - -Large intestine exhibits following histological features: o Mucosa of large intestine __________ villi and microvilli o These structural adaptations reflect fact that nutrient absorption is ________ large intestine's primary function o Mucosa is rich with ____________ cells that secrete protective and lubricating mucus o Has unique muscularis externa that bunches the colon into pockets= _____________

RBCs, nervous, perinicious

Intrinsic Factor and Vitamin B12 Deficiency - Vitamin B12 is part of metabolic functions of every cell in body; it is particularly important to formation of _____________ and normal functioning of ______________ system - Absorption requires presence of intrinsic factor an IF-B12 complex forms and then binds to enterocyte plasma membrane, which enables its absorption - Multiple conditions can impair production of intrinsic factor, including an autoimmune condition that attacks stomach, atrophy of gastric mucosa from ulcers or infections, and surgical removal of stomach for weight loss or cancer treatment - Without intrinsic factor, vitamin B12 deficiency results, even if adequate B12 is present in diet; deficiency can lead to ________________ anemia and nervous system problems; can only be treated with B12 injections

Cecum, hepatic flexure, splenic flexure, left, rectum

Large intestine: - ______________, first portion of large intestine, is a blind pouch; located in right lower quadrant of abdomen - Features a smaller blind-ended pouch extended from its posterior-inferior end, called appendix - Appendix houses multiple MALT lymphatic nodules and plays a role in immune system - Next and longest portion of large intestine is colon Colon is divided into 4 portions: 1) Ascending colon travels superiorly along right side of abdomen from right lower quadrant to right upper quadrant when it reaches liver, it makes a sharp left-handed turn at a junction called _____________ ____________ 2) Transverse colon : at hepatic flexure, ascending colon becomes transverse colon, because it passes transversely across superior abdominal cavity; at spleen, it takes a sharp turn inferiorly at a junction called ______________ ____________ 3) Descending Colon: splenic flexure gives rise to descending colon; passes along __________ side of abdominal cavity o Sigmoid colon: in left lower quadrant, descending colon becomes S-shaped sigmoid colon; and passes toward the sacrum o After sigmoid colon, large intestine continues as ____________; this portion of large intestine runs anterior to sacrum

water, secretion, propulsion, defecation, vitamins

Large intestine: - Runs along border of abdominal cavity, surrounding small intestine and other abdominal organs like a frame o Measuring about 1.5 meters (5 feet) long; so named because it has a large diameter than small intestine o Receives material from small intestine that was not digested or absorbed, and is a passageway for feces or fecal matter to exit body o Active in absorbing ____________ and electrolytes; critical for maintaining fluid, electrolyte, and acid-base homeostasis o Tasks of large intestine also include __________( in form of mucus), ______________, and ______________ o Houses numerous bacteria that perform important functions such as synthesizing ____________

mucus lining, micelles, chylomicrons, lacteal, thoracic

Lipid absorption: - Due to their nonpolar nature, lipids face several water-based barriers that deter them from passing into cytosol of enterocytes, including __________ _______________of small intestine and polar phosphate heads of enterocytes' plasma membranes: o ___________________ escort lipids to the enterocyte plasma membrane o Lipids pass through the phospholipid bilayer and enter the cytosol o Lipids are reassembled into triglycerides and packed into ____________________ o Chylomicrons are released into the intestinal fluid by exocytosis and then enter a ______________ - Lipids are not delivered directly to liver via hepatic portal vein after absorption o Hepatic portal vein delivers leftover bile salts to liver, where they are used to make new bile o Lipids travel within chylomicrons through lymphatic vessels and eventually to thoracic duct, where they join blood with rest of lymph as _____________ duct meets junction of left internal jugular and left subclavian veins o As chylomicrons travel through blood capillaries, lipids are progressively removed and enter cells, where they can be used for many different purposes

Nonpolar, mechanical, emulsification, bile salts, gastric lipase, pancreatic, micelles

Lipid digestion: - Majority (90%) of lipids taken in by diet are triglycerides: consist of three fatty acid molecules bound to a glycerol core molecule: - _______________ lipids tend to stick together, forming large globules rather than distributing evenly in a water-based solution; lipid globules can be broken up into smaller particles in two ways: o _________________ digestion: mastication in mouth, churning in stomach, and segmentation in small intestine o Bile salts in small intestine are amphiphilic o When bile salts mix with lipids, their nonpolar parts interact with lipids, while their polar parts interact with surrounding watery fluid - This breaks up lipid globules into smaller pieces by process of _________________ - Result is multiple tiny lipid droplets each coated with ____________ _____________, a mixture called an emulsion; · Gives digestive enzymes enough surface area on which to work to efficiently digest lipids - Process of lipid digestion: o Lipids are broken apart by stomach churning and broken down by ____________ ___________ o Lipids enter small intestine and are emulsified by bile salts o ________________ lipase catalyzes reactions that digest lipids into free fatty acids and monoglycerides o Bile salts remain associated with digested lipids to form ________________

metabolism, detoxification, excretion

Liver performs a host of other functions including: - Nutrient ______________: processes nutrients obtained from diet - __________________ : detoxifies substances produced by body, and substances that we eat or drink, some of which are harmful to body - _____________: directly excretes bilirubin in bile along with other substances liver processes, particularly certain antibiotics; also modifies substances so that they can be excreted by kidneys

basal rate, contraction, secretin,

More on Bile production and secretion: - Liver produces bile continually but generally does NOT secrete at a __________ ____________; - Secretion occurs in response to gallbladder ________________ and sphincter relaxation at hepatopancreatic ampulla: o This activity is mostly accomplished by CCK and to a small extend by vagus nerve o Other factors influence bile secretion, including hormone secretin - _________________: stimulates bile production and release by hepatocytes - Most potent stimulus for bile production and release is bile itself, specifically bile salts

water, increase, constipation

Motility and water content of feces - Anything that changes motility of large intestine affects amount of ________________ present in feces - When motility __________________, large intestine does not have enough time to absorb water from fecal material; produces watery feces, a condition known as diarrhea - Factors that may increase motility include irritation of colon due to bacterial or viral infections or drugs that stimulate parasympathetic nervous system - When motility decreases, it absorbs too much water and fecal material becomes hard, a condition called ___________________ - Large intestine's motility may be slowed by drugs such as opiate narcotics or those that block effects of acetylcholine (ACh)

motilin, migrating motor complex,, peristalsis, propel, segmentation, mechanical

Motility of small intestine: - Small intestinal motility differs during fasting and eating: - Fasting: slow contractions by ______________ - Eating: Peristalsis (propels) and segmentation (squeezing) - During fasting, small intestine exhibits slow, rhythmic contractions along its length in a pattern called _____________ ____________ ______________ o These contractions clear any remaining material, including leftover food and secretions o Requires about 2 hours to push digesting food from duodenum to ileocecal valve o Controlled by ENS and hormone called motilin; produced by cells in duodenal mucosa - During eating: small intestine undergoes 2 types of movement: - Peristalsis - segmentation - ______________: alternating contractions of longitudinal and circular layers of smooth muscle in muscularis externa - Primary function: ______________ chyme toward ileum and ultimately through ileocecal valve to cecum - _________________: aka intestinal churning, involves contractions of only circular layer of smooth muscle · Produces a squeezing motion · Primary functions: _________________ digestion and mixing chyme with intestinal and pancreatic enzymes as well as bile · Vagus nerve appears to regulate both peristalsis and segmentation

oligopeptides, secondary, hepatic portal vein

Protein absorption - To be absorbed in small intestine, proteins consumed for nutrition must generally be broken down into small __________________ and free amino acids o Humans do have ability to absorb small amounts of whole, undigested proteins involved in immunity by process of endocytosis o Specialized cells overlying Peyer's patches in small intestine endocytose these proteins and deliver them to lymphatic tissue in patches - Oligopeptides and free amino acids cross enterocyte apical membrane primarily by ________________ active transport membrane proteins that use a sodium ion gradient established by Na/K pump o Within enterocyte, oligopeptides are broken down into free amino acids o Free amino acids then exit basal enterocyte membrane by facilitated diffusion, after which they enter capillaries in villus o Like carbohydrates amino acids are then delivered to liver for processing via ____________ ____________ _______

Segmentation, absorption, mass movement

Proximal large intestine: primary site of water and electrolyte absorption and bacterial activity - 2 main types of motility 1) ____________________ (churning) - Circular muscle contracts repeatedly - Swirls material around in haustrum - Aids in water and electrolyte __________________ - Primarily controlled by local neurons of ENS; triggered by STRETCH 2) ____________ _______________ - During a mass movement, multiple haustra undergo peristalsis - Propels their contents toward distal large intestine - Mass movements occur 3-4x per day, and appear to be triggered by food consumption

cephalic, hydrogen, hydrogen, serotonin, somatostatin, gastric phase, intestinal, proteins, gastrin

Secretion phases: 1)________________ phase: mediated by sight, smell, taste or even thought of food - Prepares stomach to receive food by increasing release of hydrogen ions into it - Stimulates gastrin--> triggers ______________ ion secretion - Stimulates histamine--> triggers _______________ ion secretion - ______________________--> > stimulates gastric motility (stomach muscles contract) - Inhibits _______________ secretion--> somatostatin inhibits acid secretion, so during the cephalic phase, the nervous system inhibits somatostatin release which increases hydrogen ion secretion 2) __________ ____________: begins when food enters stomach; continues stimulation provided during cephalic phase 3) _____________ phase: : final phase of gastric acid secretion that is responsible for only about 10% of remaining aid secretion, after which it inhibits further acid secretion - Triggered by presence of partially digested ______________ in fluid entering duodenum; - a. Triggers enteroendocrine cells to release intestinal ______________ - This hormone has same effect of gastrin produced by the stomach - a. Stimulates hydrogen ion secretion from parietal cells

duodenum, papilla, brunner's, jejunum, Ileum, Ileocecal

Small intestine has 3 divisions: 1) ___________________: initial segment; begins at pylorus; shortest of three divisions - Houses major duodenal __________________; where secretions from gallbladder and pancreas enter small intestine - Duodenal submucosa contains specialized glands called duodenal (_________________) glands; produce alkaline mucus to protect duodenum from acidic chyme 2) _____________: middle; most active site for chemical digestion and absorption 3) _____________: Small intestine's final segment, measures about 10.8 feet in length; terminates at portion of large intestine called cecum - _______________ valve: sphincter that controls movement of materials from ileum to cecum - Also prevents materials in large intestine from flowing backward into ileum; critical for preventing access to bacteria from large intestine

6, enterocytes, small intestine

Small intestine: - _______ meters long (almost 20 feet); longest portion of alimentary canal - 4 main processes occur in small intestine: secretion, digestion, absorption, and propulsion - Cells of the small intestine, known as ___________________, produce multiple digestive enzymes, hormones, and mucus - Enzymes, along with those released by pancreas are responsible for bulk of chemical digestion - No further nutrient digestion takes place by human enzymes once food leaves ______________ ____________ (bacteria in large intestine digest certain nutrients) - After nutrients are digested chemically, they are absorbed across enterocytes into either blood or lymph, along with water, vitamins and other substances -Small intestine also mixes and propels its contents along with length and into large intestine

absorption, circular folds, slows, villi, intestinal crypts, microvilli, brush border

Structure and functions of the small intestine - Internal folds of small intestine: - Internal surface of small intestine contains 3 progressively smaller types of folds o Most ________________ that occurs takes place in this region; o Folds increase surface area available for absorption about 400 to 600 times - Largest type of folds, visible with naked eye as ridges in wall, are called ____________ _________________ o Circular folds involve both mucosa and submucosa of small intestine ;increase surface area o Folds also _____________ down transit of chyme through small intestine; giving nutrients more time to be digested and small intestine cells (enterocytes ) more time to absorb nutrients 2 types of smaller folds are NOT visible to naked eye: 1) ______________ - These are small projections in the mucosa folds; each villus consists of a layer of enterocytes surrounding a central core of blood capillaries and a lymphatic vessel called a lacteal - a. Between villi mucosa indents form ___________ ______________; house glands with both enteroendocrine cells and mucus-secreting goblet cells 2) _______________ - Smallest folds found in plasma membrane of enterocytes - Each enterocyte has as many as 3000 microvilli - Gives cell appearance of a bristle brush, or ________ _________ - Digestive enzymes produced and secreted by enterocytes catalyze reactions that break down disaccharides and peptides

propulsion and a small amount of secretion

The esophagus performs what two processes

concentrates, CCK, common bile duct, hepatopancreatic, gallstones

The gallbladder - Small sac that sits on posterior liver, receives most of bile from common hepatic duct o Stores bile, _________________ it (removes water), and releases it when stimulates o Bile release is stimulated by __________ - CCK- triggers contraction of smooth muscle in wall of gallbladder, causing gallbladder to release bile into cystic duct o Cystic duct joins common hepatic duct to form ____________ ____________ ______________; joins main pancreatic duct near duodenum to form hepatopancreatic ampula o Ampulla is surrounded by a ring of smooth muscle called _____________________ sphincter; controls emptying of bile and pancreatic fluid into duodenum o Contents of hepatopancreatic ampulla empty into duodenum at major duodenal papilla o Bile contains calcium salts and cholesterol; both can precipitate and form hard lumps called ______________

secretion, propulsion, absorption, defecation

The large intestine performs what 4 functions?

ingestion, secretion, digestion, propulsion

The mouth performs what 4 processes?

propulsion

The pharynx performs what process?

secretion, propulsion, absorption, digestion

The small intestine performs what 4 functions?

secretion, propulsion, digestion

The stomach performs what three functions?

stratified squamous, lingual frenulum

Tongue: - A skeletal muscle covered with a layer of ____________ _____________ epithelium - attached to floor of oral cavity by a thin band called _____________ ______________ - skeletal muscles control tongue movement: - Move tongue during chewing - help turn food into a bolus - push the food against hard palate during chewing, which assists in mechanical digestion - push bolus posteriorly during swallowing

Apical, excreted

Understanding absorption in Alimentary Canal: - To travel from lumen of alimentary canal to blood, a molecule must cross barriers; o Sometimes small molecules (water) can cross between enterocytes instead of through them o _____________ side of plasma membrane is the most significant barrier to absorption of ingested molecules - Most substances require a transport protein or channel to cross membrane o If no such protein exists, substance will remain in lumen and eventually be _______________ o Can be beneficial by helping prevent absorption of harmful chemicals

mucosa, submucosa, muscularis externa, serosa/adventitia

What are the 4 tissue layers in order?

liver lobule, portal triad

__________ ___________ :- basic unit of liver, has following histological features: o Composed of flattened plates of cells, called hepatocytes arranged in shape of a hexagon and stacked on top of one another with a small central vein in each lobule's center o ___________ ____________- at each of 6 corners of lobule (3 structures) - a hepatic arteriole - portal venule - a small bile duct that carries bile

greater omentum

_____________ ___________________: consists of 4 layers of folded visceral peritoneum - extends from base of stomach down to pelvis

Chemical digestion, hydrolysis, enzymatic, blood stream

______________ ___________: chemical bonds between food molecules are broken - Chemical digestion varies for each nutrient because digestive enzymes are specific for a single type of bond in a single type of nutrient - Most digestive enzymes catalyze __________________ reactions that use a water molecule to break a bond between two molecules: o This explains why so much water is secreted with fluids like gastric and pancreatic juices; water molecules are key components of reactions that chemically break down food molecules o Digestive enzymes speed up these reactions by a process known as ________________ hydrolysis - Once nutrients are digested into component molecules, they must enter body o Mucosa of alimentary canal is an external membrane o Nutrients and other molecules must be absorbed across epithelial lining of alimentary canal and enter _______________ before they can be delivered to body cells

secondary dentition, 32

______________ _______________: - When a child is about 6 years of age, these teeth enlarge and begin to press on deciduous teeth - Causes root to gradually dissolve and deciduous tooth falls out of bone - permanent tooth then erupts and takes its place - There are __________ permanent teeth with, 4 incisors, 2 canines, 4 premolars, and 6 molars in both mandible and maxilla - Third set of molars, known a wisdom teeth, erupt somewhat later between ages 17 and 21

enamel

______________: - Composed almost fully of secreted calcium hydroxyapatite crystals with only a small amount of organic material - Hardest substance in body, allowing it to endure forces that accompany chewing; - Cells that secrete enamel deteriorate after a tooth erupts, so the body cannot repair damaged enamel

pancreas, endocrine, exocrine, head, body, pancreatic duct

_______________: Gland with both endocrine and exocrine functions - Its _____________secretions: hormones insulin and glucagon affect most cells in body - Its ________________ secretions: are enzymes secreted primarily by clusters of acinar cells - Enzymes are released into ducts of pancreas that empty into alimentary canal - Pancreas, found primarily in left upper quadrant of abdomen, where it extends from duodenum to spleen, - Is composed of 3 regions: 1) ______________: wide secretion that is in contact with the duodenum 2) ____________: separates head from thinner tail (3), which tapers off toward spleen - Main pancreatic duct travels down middle of pancreas where it receives secretions from acinar cells - Near duodenum, main pancreatic duct merges with duct from liver and gallbladder, after which it empties into duodenum o Acinar cells, are found in clusters known as acini - Each acinus surrounds a small duct into which its cell secretion their products - Most of these small ducts merge and drain into main _________ ___________, although some secrete into smaller pancreatic duct

Pulp, root canal

_______________: contains blood vessels and nerves that supply other tissues of the tooth with nutrients and innervation - pulp cavity extends into root via thin ___________ _____________

Vitamins, polar, nonpolar, intrinsic factor, micelles

________________: Chemicals generally provided by diet that are involved in a host of metabolic reactions - 2 types of vitamins o Water-soluble vitamins: __________________ molecules o Fat- soluble vitamins: are lipid-based and mostly ________________ - Most water-soluble vitamins are absorbed in small intestine by diffusing through enterocytes' plasma membranes - One important exception is Vitamin B12, which must bind to ____________ _____________- a molecule produced by parietal cells of stomach- to be absorbed in ileum - Fat soluble vitamins are packaged into _______________ and fats and other lipids and are absorbed with them; fat soluble vitamins include A, D, E, and K

crown

________________: Visible portion of tooth (above gum - Consists of outer layers of hard mineralized substances called enamel, covers a soft, inner gelatinous substance called pulp

Saliva, salivary amylase, lysosome, IgA, bicarbonate ion

________________: consists primarily of water; electrolytes such as sodium, chloride, and potassium ions, and variable amounts of mucus, depending on type of salivary gland; also contains following components: - _______________ ________________: first digestive enzyme that ingested food encounters; catalyzes beginning of carbohydrate digestion, breaking down large polysaccharides into smaller polysaccharides - Enzyme _________________ catalyzes perforation of bacterial plasma membranes; allows bacteria-killing substances in saliva to enter and kill bacteria - Secretory _____________ is found in body's secretions, including saliva; - IgA binds specific antigens on pathogens and mediates their destruction - ___________________ ____________ function to neutralize any acid from stomach that regurgitates into esophagus

Oropharynx, Laryngopharynx, propulsion

___________________ and _______________________ are part of the alimentary canal - Primary function of the pharynx is _____________ in the form of swallowing, during which bolus passes through pharynx and into esophagus

Root, cementum, dentin

_____________________: embedded within the alveolus - __________________: found on outer portion of root of tooth - Is a different kind of mineralized bonelike tissue - Inner layer of mineralized tissue in both root and crown is _____________ · Composed of about 70% calcium hydroxyapatite crystals o Has some decree of elasticity; critical for preventing overlying enamel from fracturing when chewing hard substances

cholesterol, emulsification, excretes

o One of bile's main organic compounds is bile salts, derived from _______________ - Bile salts are amphiphilic, meaning they have both polar and nonpolar parts · Allows them to interact with both lipids and watery environment of small intestine - Coat lipids in duodenum and physically breaks them apart into smaller pieces, a process known as ________________; mechanical digestion necessary for chemical digestion of absorption of lipds - Bile also contains varying amounts of materials that liver _____________, including cholesterol, waste products, and toxins such as heavy metals - Most of these products are not reabsorbed by small or large intestines and so pass into feces

rectal valves, involuntary, voluntary

o Walls of rectum feature horizontal folds called ___________ ___________; allows passage of gas without risking simultaneous passage of feces o Rectum ends at anal canal, last portion of large intestine o Terminal portion of anal canal has 2 sphincters 1) Internal anal sphincter- is _______________ 2) External anal sphincter: is ________________

distal large intestine

o consists of descending and sigmoid colon, rectum, and anal canal