ch 25 and 26 test review Flashcards
spleen is NOT involved in
digestion
gallbladder Is involved in
digestion
cecum is the beginning of the
large intestine
what is voluntary of the digestive system
- chewing
- swallowing
- defecating (holding it in)
what is involuntary of the digestive system
- everything after swallowing
- defecating if you really have to go
alimentary canal
- mouth
- pharynx
- esophagus
- stomach
- small intestines
- large intestines
accessory organs
- teeth
- tongue
- salivary glands
- liver
- gallbladder
- pancreas
saliva measured by
brain
salivation amount is determined by how much water is needed to
break down the food
* brain calculates how much you need
5 stages of digestion
5 stages of digestion
- ingestion
- digestion
- absorption
- compaction
- defecation
5 stages of digestion
- ingestion
selective food intake
5 stages of digestion
- digestion
mechanican and chemical breakdown of food into a form usable by the body
5 stages of digestion
- absorption
uptake of nutrient molecules into the epithelial cells of the digestive tract and then into the blood and lymph
5 stages of digestion
- compaction
absorbing water and consolidaitng the indigestable residue into feces
5 stages of digestion
- defecation
elimination of feces
digestion
mouth
- more than 700 microorganisms; almost 1/2 bacteria
- teeth: chewing (mastication)
- tongue: taste, push to swallow, move food around
- salivary glands
mechanical digestion
- cutting or grinding action of teeth
- churning action of stomach and small intestines
- exposes more food surface to digestive enzymes
chemical digestion
- series of hydrolysis reaction that breaks down dietary molecules into their monomers
- carried out by digestive enzymes produces by salivary glands, stomach, pancreas, small intestine
products of chemical digestion
- polysaccharides into monosaccharides
- proteins into amino acids
- fats into monoglycerides and fatty acids
- nucleic acids into nucleotides NOT NUTRIENT DNA
digestive tract wall consisting of layers
- mucosa: epithelium, lamina propria, muscularis mucosae
- submucosa
- muscularis externa: inner circular layer, outer longitudinal layer
- serosa: areolar tissue, mesothelium
teeth
- kids have 20
- adults have 32
- occlusion: meeting of the teeth when mouth is closed
- occlusal surfaces: of premolars and molars have cusps (bumps) that aid in grinding during chewing
chemical composition of saliva
- mucus: binds and lubricates a mass of food and aids in swallowing
- electrolytes: salts of Na, K, Cl, phosphate, bicarbonate
- lysozyme: enzyme that kills bacteria
- immunoglobulin A (IgA): antimicrobial antibody
- salivary amylase: enzyme that beings starch digestion in the mouth
- lingual lipase: enzyme that begins fat digestion in the mouth (mainly after food is swallowed)
serous cells
mucus cells
serous cells: outside, water, jello like
mucus cells: inside
intrinsic (minor) salivary glands
- small glands dispersed amid other oral tissues
- secretes saliva at constant rate (whether we are eating or not)
- lingual glands: in tongue; produce lingual lipase
- labial glands: in lips
- palatine glands: of palate
- buccal glands: in cheek
extrinsic (major) salivary glands
- 3 pairs of larger more discrete organs connected to oral cavity by ducts
- parotid glands: located beneath the skin anterior to the earlobs; parotid duct passes over masseter, pierces buccinator, and opens in mouth
- submandibular gland: halfway along the body of the mandible; its duct empties at the side of the lingual frenulum, near the lower central incisors
- sublingual gland: in flood of mouth; has multiple ducts that empty posterior to the papilla of the submandibular duct
esophagus: phases of swallowing
phases of swallowing
- oral phase
- pharyngeal phase
- esophageal phase
esophagus: phases of swallowing
- oral phase
- voluntary
- tongue collects food, presses it against palate forming bolus and pushes it back posteriorly
- food accumulates in oropharynx in front of epiglottis
- epiglottis tips posteriorly and food bolus slides around it and into laryngopharynx
esophagus: phases of swallowing
- pharyngeal phase
- involuntary
- prevents food and drink from reentering mouth or entering the nasal cavity
- palate, tongue, vocal cords and epiglottie block the oral and nasal cavities and airway while pharyngeal constrictors push the bolus into the esophagus
esophagus: phases of swallowing
- esophgeal phase
- peristalsis drived the bolus downward and relation of the lower esophageal spincter admits it into the stomach
why can we swallow looking down
not controlled by gravity the esophagus pushes the food down by peristalsis (smooth muscles contracting)
stomach
chyme
- food is mechanically broken down into food particles, liquifies the food, and begins chemical digestion of proteins and fat
- results in chyme—acidic, soupy mixture of semidigested food that passes on to the small intestine
stomach
pyloric sphincter
- ring of smooth muscule around pylorus; regulates the passage of chyme into the duodenum
- pylorus: narrow passage to duodenum
stomach
parietal cells
cheif cells
- parietal cells: secrete HCl, intrinsic factor, ghrelin (hunger)
- cheif cells: secrete gastric lipase, pepsingogen–> pepsin–> break down amino acids (protein)
- HCl is needed to convert pepsingogen into pepsin
- BOTH CELLS COMMUNICATE
stomach
gastric juice
- 2-3L per day produced
- mainly a mixture of water, Hydrochloric acid, pepsin
stomach
HCl activates
- pepsin
- lingual lipase
- breaks up connective tissues and plant cell walls, help to liquefy food and form chyme
- contributes to innate immunity by destroyinh most ingested pathogens
stomach
gastric phases
- cephalic phase: stomach being controlled by brain
- gastric phase: stomach controlling itself
- intestinal phase: stomach being controlled by small intestine
- phases overlap and can occur simultaneously
small intestines
- absorption
- duodenum
- jejunum
- ileum
large intestine
water absorption
liver secretes and produces
bile
hepatocyte
cell of liver
pancreas
bile and pancreatic juice are combined by ducts, not random, measured by brain from receptors
pancreatic juice
- trypsinogen–> trypsin
- chymotrypsinogen–> chymotrypsin
- procarboxypeptidase–> carboxypeptidase
energy balance
- body weight is determined
- stable: energy intake = output
- gain weight: intake exceeds output
- lose weight: output exceeds intake
- 30% to 50% in weight is hereditary
appetite
- feel hungry
- satiety: feeling full
- ghrelin: HUNGER HORMONE; secreted from parietal cells
- peptide YY: sense food has arrived; primary effect is to signal satiety and stop eating;
- cholecystokinin (CCK): secretion of bile and pancreatic enzymes; signals to stop eating
amylin
- produces satiety (feel full)
- inhibits stomach activity
leptin
how much fat is in the body
insulin
weaker effect on appetite
calories
- carbs: 4kcal; 70%
- protein: 4kcal 13%-15%
- fats: 9kcal
cholesterol
holds cell’s membrane to make it more rigid in phospholipid
protein
12% to 15% to total body mass
skeletal muscle
65% to total body mass
why do you mix food
have a balanced diet
minerals and vitamins are not used for
fuel
help other nutrients to do their job
if you do not have glycogen then
fats, proteins (muscles) is broken down
metabolic rate
the amount of energy liberated in the body in a given period of time
(kcal/hr or kcal/day)
core temp
temp of organs in cranial, thoracic, and abdominal cavities
rectal temp is an estimate
adult temp varies from 99 to 99.7
shell temp
temp close to body surface (oral cavity and skin)
slightly lower than rectal temp
adult varies from 97.9 to 98.6
skeletal muscle contribute to
20% to 30% of total resting heat
