module 3 digestive system Flashcards
what are the 2 main groups of the digestive system
alimentary canal( GI tract) accessory
What is composed of the alimentary canal( GI tract)
mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus
What is included in accessory digestion tract
teeth, tongue, gallbladder, salivary glands, liver and pancreas
Describe the anatomy of the mouth and function
beginning of digestive tract
lips form opening; tongue forms the floor, cheeks form the wall, hard and soft palate form the root, uvula forms posterior border
Describe the tongue
muscle: attaches to hyoid bone, mandible and lingual frenulum
works to move food around and move bolus back toward pharynx for swallowing
apex- anterior portion
root- posterior portion
What is the lingual frenulum
vertical mucous membrane attaches body of tongue to floor of mouth
What is mastication
act of chewing food by teeth, food is mixed with saliva and enzymes
what is amylase
only enzyme that begins chemical digestion in the mouth for carbohydrates
How many teeth are there
32
Describe the structure and function of teeth
upper teeth located in maxilla lower teeth in mandible root- alveolar process of jaw bone neck- 1 portion of gum( gingiva) crown- visible portion- lie above gum line
What is the pulp cavity
contains nerves and blood vessels
What are the 4 types of human teeth
incisor(2)- bite
canine(1)- tear
pre-molar(2)- grinding
molar(3)- crushing
What is enamel
hard connective tissue located on surface of crown- protects teeth
What are papillae
raised bumps on tongue
What are the 3 types of papillae
circumvallate, fungiform, filiform
Which 2 types of papillae contain taste buds
circumvallate and fungiform
What is a taste bud
chemical receptor stimulated by chemical compositor of food, found on tongue surface, mouth and wall of pharaynx
what are the 3 parts of the pharanx and which allow air/food/water to pass through
nasopharynx- air only
oropharynx- air, food, drink
laryngopharanx- air, food, drink
What are the 2 types of skeletal muscle and their function in the pharaynx
circumferential and innter longitudinal
contract to cause peristalsis squeeze food into esophagus
What prevents food from entering laraynx
the epiglottis
what is aspiration
food and liquid enter lung and could cause phneumonia
what is the esophagus
extends from pharynx to stomach through opening in diaphragm
muscular tube: 4 levels of tissue
What are the 4 layers of tissue in the esophagus
- innermost: mucosa- secretes mucous into interior of GI
- submucousa- contains blood, lymph vessel, lymph node, nerve and mucous gland
- muscularis externa- 2 layer of muscle- outer longitudinal and inner circumferential
- outermost is serosa- cells make serous fluid
Describe the function of the stomach
food enters via cardiac sphincter/ LES( lower esophageal sphincter)
food exit pyloric sphincter into small intestine
Describe anatomy of stomach
backward C shaped organ located L side of abdomen below diaphram 2 curvature: concave- lesser; convex- greater has 4 parts serous membrane peritoneum covers
What is the serous membrane covering stomach called
- lesser omentum: attach lesser curvature to posterior wall
2. greater omentum: attacher greater curvature to anterior surface of small intestine
What are the 4 main parts of the stomach
cardiac sphincter: food enter from esophagus
fundus: dome top of stomach under diaphram
body: wide mid portion between fundus and fourth part of stomach
pyloric region: funnel shaped- leads food to small intestine
What are the 2 main purposes of the stomach
temporary storage for food- up to 2 L of partially digested food
Mechanical food breakdown- utilizes additional layer of tissue: muscularis externa
What does the musclaris eterna do( oblique layer)
allow stomach to mix food efficiently with gastric juices- breaks down food into small pieces for digestion and later absorption
What are ruggae
folds in stomach wall- allow stomach to expand when it is full
What is a primary protective mechanism for the walls of the stomach and intestines
a thick mucous layer
What can develop if gastric juices breakdown the gastric lining of stomach and intestine
ulcer
What can cause ulcers
H. Pylori: bacterial infection, overuse of NSAID
once a hole develops- gastric juice enter and area in abdomen and cause bleeding/damage to other organs
what is chyme
contents of stomach: usually thick and soupy
Describe the pyloric sphinctoer
base of stomach and has a valve in it
relaxation of valve cause small quantity of chyme to pass through opening into duodenum
after chyme enters, sets of reflex cause muscle to contract and close opening temporarily
then open again to allow more chyme
slow process- allows for thorough digestion
Describe the small intestine
coiled tube 20 ft long and runs from pyloric sphincter to ileocecal valve- entry to colon
longest part of the GI tract
Has 3 sections
What are the 3 sections of the small intestine
duodenum: shortest section: enzymes from pancreas and bile from liver enter here
jejunum
ileum: slightly longer than jejunum
What increases the surface area allow for better digestion
circular folds which have villi
surface area is increased to 1800 square feet
what are villi
finger like projections that have small projection called microvilli
How is the small intestine specialized for absorption
molecules are absorbed by villi that line the wall
each villus contain blood vessel and lymphatic vessel called lacteal
sugar and amino acid villi cells- absorbed through capillary bed in villi
nutrients carried to hepatic portion circulate before entering general blood supply
molecules too lg enter blood capillaries transport in lacteal
epithelium cells of villi produce intestinal enzyme- remain attached to plasma membrane of microvilli
enzymes complete digest of sugars and amino acids
What is the tract for the Lg intestine( colon)
travels from ileocecal valve to anus
muscle contraction moves chyme through colon to be excreted as feces
What are the 8 parts of the colon
- )cecum: entrance to lg intestine through ilieocecal valve
- )appendix: hang from cecum- is twisted
- )ascending colon: run on R side of abdomen superiorly
- )transverse colon: begins after 90 degree turn at R hepatic flexure and runs across abdomen
- ) descending colon: begins after 90 degree of L splenic flexure: run along L side abdomen superiorlyy to sigmoid
- ) sigmoid: travel through pelvis connects to rectum
- ) rectum: connects anal canal: last 20 cm of lg intestine
- ) anus: feces expelled- end of GI tract
what is appendicitis’s
bacteria causes inflammation and pain in appendix
usually results in appendectomy
What does the involuntary smooth muscle of internal sphincter and voluntary sphincter do for colon
together open and close during defecation to get rid of waste
What is the major function of lg intestine
propel waste from body
reabsorb water and electrolytes
How much water is used in fecal matter and how much is absorbed and released
1.5 L of water enter because of food and drink
8.5 L/day enter GI tract carry enzyme secreted by digestive glands
95% water absorbed in small intestine
feces: 75% water, 25% solid matter,
What is the make up of fecal matter
1/3 of matter= intestinal bacteria
remained: undigested plant, fat, waste, dead cell, mucous, inorganic materials
What happens when water passes too quickly through digestive system
results in diarrhea
if too slow- constipation
extreme diarrhea= loss of vitamins B, D, and results in loss of electrolytes and increases dehydration
What are the 3 important organs of accessory digestive system
liver
pancreas
gallbladder
What is structure and function of pancreas
lies deep in abdominal wall
sends pancreatic juice in duodenum via pancreatic duct
pancreatic juice contain sodium bicarbonate- neutralize chyme
What are the pancreatic enzymes and their functions
amylase: digest starch to maltose
trypsin: digest protein to peptides
lipase: digest fats to glycerol and fatty acid
travel in pancreatic duct to hepatic pancreatic ampulla in duodenum
what percent of pancreas function is digestive: 99%
What are the 3 important functions of the liver
- produce bile:
- store glucose as glycogen
- produces urea from amino groups removed from excess amino acids
What is bile and where is it stored
stored in gallbladder
emulsify fat
sent to duodenum by common bile duct
looks green as pigments product of hemoglobin
contains bile salt- emulsify agent break up fat to mix with water- therefore acting on enzymes easily
Why does liver store glucose as glycogen
has solid food source to keep homeostasis during periods in-between meals
What are the 4 rolls in the physiology of digestive tract
- ingestion: food enter mouth
- digestion: food break down: 2 parts: mechanical and chemical
- absorption: move food digested into blood stream
- defecation: excretion of indigestible food form anus
Describe process of digestion physiologically in mouth
Digestion begin in mouth: chemical saliva is released by salivary glands
Amylase in saliva begin break down of starch
Bolus swallowed by pharaynx- peristalsis move bolus along esophagus to stomach
no injection, digestion absorption, defecation take place in pharynx or esophagus
Describe digestion physiologically in stomach
Hormone gastrin stimulate stomach to secrete gastric juice contain: pepsinogen, mucous and HCL
secrete HCL to activate pepsin
Pepsinogen: pre-enzyme secreted in stomach
HCL: convert inactive pepsinogen into active enzyme pepsin: break down pepsin
mucous: protect stomach lining from HCL and pepsinogen
peristalsis move food toward sm. intestine where pyloric sphincter control release chyme into duodenum
Describe digestion physiologically in sm. intestine
digestion continue: absorption begin
pancreatic enzyme enter to cont. digest starch, protein and fat
What is peptide
results in first step in protein digestion
digested by peptidases to amino acids
What is maltose
digested by maltase to glucoses by 1rst step in starch digestion
other disaccharides digested in sm. intenstine
What does pancreatic juice contain
amylase, trypsin, lipase
digest starch, protein and fat
sodium bicarbonate: neutralize acidic chyme
which 2 hormones are stimulated to be secreted by chyme
cholecystokinin: cause gallbladder to secrete bile
secretin: cause liver to secrete bile
What is key to know once food reach end of sm. intestine
digestion is complete and most of absorption of nutrients has happened into blood stream
What happens physiologically after the sm. intestine.
food in lg intestine is compacted in to order to be defecated
water is absorbed to form feces
vitamin and ion absorbed
bacteria metabolize nutrients, produce vit K and B
feces travel to rectum where is defecated by anus
what is hunger
internal drive to eat food
what is satiety
sensation of being full
what part of brain regulate hunger/satiety
hypothalamus
what other factors contribute to feeling of satiety
stomach: as expands, receptors in stomach wall send signal to brain and desire to eat declince
hormones
What hormones play a role in hunger
grenlin
endorphin
neuropeptide-y
what hormones play a role in satiety
leptin
serotonin
cholecystokinin
define ghrenlin
produced by stomach, stimulate hunger, deactivate satiety
define leptin
produced by fat cells
altert brain turn hunger center- activate satiety
What are 3 biochemical categories of food body needs
carb, fat, protein
What are carbohydrates
starches and sugar
milk and fruit- sugar
grain and potato- starch
What are lipids
3 categories: saturated, unsaturated, cholesterol
saturated: meat and cheese
unsaturated: nuts and seeds, olive oil
cholesterol: made by bodies, ingested in animal products
What are proteins
amino acids
complete: meat, dairy, soybean
incomplete: grain, legume and seeds
essential: 9 of them- need to take in from environ. body can’t produce
What are vitamins needed
organic compound not consumed metabolic reaction: help enzyme carry out metabolic reaction
water soluable- stored in body- excreted in urine
fat soluble- stored in body fat
what are minerals needed
inorganic compounds- not used in metabolic reaction
what are the 7 needed minerals
calcium, chloride, magnesium,phosphorus, potassium, sodium, sulfur
define metabolism
chemical reaction in body to sustain life
what is anabolism
smaller molecules are combined to build larger one
what is catabolism
breakdown of larger structure into more simple
What is ATP
energy in the cell
will donate a phosphate to become ADP
How many ATP are produced with glucose metabolism
38
glycolysis: 2
cellular respiration: 2- krebs cycle
electron transport chain: 34
what is glycolysis
breakdown of glucose into 2 pyruvate and H+
yield 2 atp
What is cellular respiration
aerobic- in mitochondria
fermentation: no o2
Krebs cycle: unlock energy from pyruvate
produce 2 ATP and NADH, FADH2
What is electron transport
continuation of cellular respiration
aerobic or anaerobic
at end is 34 ATP
proton motive force drives H+ back through ATP synthase complex
Describe lipid metablism
beta oxidation in liver
lipids used in body during lower energy activity
yields 2x ATP than carbohydrates
fats broken down into acetic acid-> further catabolized by TCA to CO2
electron transport chain convert H+ atom to H2O-> released energy used to add phosphate to ADP->ATP
Describe protein metabolism
takes place when carb and fat unavailable
profile block to cell used as last option
when used: amino group is removed to form ammonia
remained of molecule enter TCA to form CO2 and ATP; H+ converted to H2O-> releases energy converts ADP->ATP
ammonia is harmful to body and must be converted to different form
ammonia combined with CO2 in liver create urea-> then excreted as urine
