Digestive System Flashcards
- Take in food
- Break down food
- Absorb digested materials
- Provide nutrients
- Eliminate waste
digestive system
Layer of the smooth epithelial tissue
peritoneum
connective tissue of organs in abdominal cavity
mesenteries
mesentery connecting lesser curvature of stomach to liver and diaphram
lesser omentum
mesentery connecting greater curvature of stomach to transverse colon and posterior body wall
greater omentum
- First part of digestive system
- Contains stratified squamous epithelia
oral cavity
- produce saliva which contains enzymes to breakdown carbohydrates into glucose
- cleanse mouth
- dissolve and moisten food
salivary glands
salivary enzyme that breaks down
carbohydrates
amylase
salivary enzymes that are active against bacteria
lysozyme
house taste buds and mucus
tongue
_______ is hard covering protects against abrasions
enamel
how many teeth in a normal adult?
32
how many primary (baby) teeth?
20
Center of tooth is ______
pulp cavity
______ are breakdown of enamel by acids from bacteria
cavities
roof of oral cavity
palate
anterior part of palate
hard palate
posterior part of palate
soft palate
- includes submandibular, sublingual, parotid
- produce saliva contains enzymes to breakdown food
salivary gland
inflammation of parotid gland
mumps
Type of secretion of parotid gland
purely serous
Type of secretion of submandibular gland
mixed predominantly serous
Type of secretion of sublingual gland
mixed predominantly mucous
- Throat
- Connects mouth to esophagus
pharynx
- Tube that connects pharynx to stomach
- Transport food to stomach
- Joins stomach at cardiac opening
esophagus
- occurs when gastric juices regurgitate into esophagus
- caused by caffeine, smoking, or eating or drinking in excess
heartburn
Phases of swallowing
- voluntary phase
- pharyngeal phase
- esophageal phase
- peristalsis
Swallowing phase: bolus (mass of food) formed in mouth and pushed into oropharynx
voluntary phase
swallowing phase: swallowing reflex initiated when bolus stimulates receptors in oropharynx
pharyngeal phase
swallowing phase: moves food from pharynx to stomach
esophageal phase
swallowing phase: wave-like contractions moves food through digestive tract (Myenteric plexus/Auerbach’s plexus)
peristalsis
- Located in abdomen
- Storage tank for food
- Produces mucus, hydrochloric acid, protein digesting enzymes
- Contains a thick mucus layer that lubricates and protects epithelial cells on ______ wall form acidic pH (3)
- Can hold up to 2 liters of food
stomach
Function of the _______ of the stomach is to produce churning action
thick muscular layer
Function of the _______ of the stomach acts as the large folds that allow stomach to stretch
rugae
Function of the _______ of the stomach is the paste-like substance that forms when food begins to be broken down
chyme
opening between stomach and small intestine
pyloric opening
thick, ring of smooth muscle around pyloric opening
pyloric sphincter
stomach is stimulated to contract by low blood glucose levels usually 12-24 hours after a meal
hunger pangs
3 phases of regulation of stomach secretions
- cephalic phase
- gastric phase
- intestinal phase
Parasympathetic stimulation, gastrin, histamine increase stomach secretions
regulation of stomach secretions
- 1st phase of stomach secretion regulation
- stomach secretions are initiated by sight, smell, taste, or food thought
cephalic phase
- 2nd phase of stomach secretions regulation
- partially digested proteins and distention of stomach promote secretion
gastric phase
- 3rd phase of stomach secretion regulation
- acidic chyme stimulates neuronal reflexes and secretions of hormones that inhibit gastric secretions by negative feedback loops
intestinal phase
2 types of waves in the stomach
- mixing waves
- peristaltic waves
Stomach waves:
- weak contraction
- thoroughly mix food to form chyme
mixing waves
stomach waves:
- stronger contraction
- force chyme toward and through pyloric sphincter
peristaltic waves
_____ and _____ stimulate stomach secretions
Hormonal, neural mechanisms
Stomach empties every _ hours after regular meal, and ___ hours after high fatty meal
4, 6-8
What does surface mucous cells secrete?
mucin in an alkaline fluid
what does mucous neck cells secrete?
mucin in an acidic fluid
what does parietal cells secrete?
HCL & intrinsic factor
what does chief cells secrete
pepsinogen & lipase
What does G cells/enteroendocrine cells secrete?
gastrin
- Measures 6 meters in length
- Major absorptive organ
- Chyme takes 3-5 hours to pass through
- Contains enzymes to further breakdown food
- Contains secretions for protection against chyme’s acidity
Small intestine
3 parts of the small intestine
- duodenum
- jejunum
- ileum
part of small intestine:
- 25 cm long
- contains absorptive cells, goblet cells, granular cells, endocrine cells
- contains microvilli and many folds
- contains bile and pancreatic ducts
duodenum
part of small intestine: 2.5 meters long and absorbs nutrients
jejunum
part of small intestine: 3.5 meters long
ileum
- Function is to absorb water from indigestible food
- Contains cecum, colon, rectum, anal canal
large intestine
- joins small intestine at ileocecal junction
- has appendix attached
cecum
9 cm structure that is often removed
appendix
- 1.5 meters long
- contains ascending, transverse, descending, sigmoid regions
colon
straight tube that begins at sigmoid and ends at anal canal
rectum
last 2-3 cm of digestive tract
anal canal
Food takes how long to pass through?
18 - 24 hrs
a product of water, indigestible food, and microbes
feces
Microbes synthesize vitamin __
K
- Weighs about 3 lbs.
- In right upper quadrant of abdomen under diaphragm
- Right, left, caudate, quadrate lobes
- contains porta
- Receives blood from hepaticartery
liver
gate where blood vessels, ducts, nerves enter and exit
porta
4 liver ducts
- hepatic duct
- common hepatic duct
- cystic duct
- common bile duct
liver duct: transports bile out of liver
hepatic duct
liver duct: formed from left and right hepatic duct
common hepatic duct
liver duct:
- joins common hepatic duct
- from gallbladder
cystic duct
liver duct: formed from common hepatic duct and cystic duct
common bile duct
- Small sac on inferior surface of liver
- Stores and concentrates bile
gallbladder
- Digestive and excretory functions
- Stores and processes nutrients
- Detoxifies harmful chemicals
- Synthesizes new molecules
- Secretes 700ml of bile each day
functions of liver
dilutes and neutralizes stomach acid and breaks down fats
bile
- Located posterior to stomach in inferior part of left upper quadrant
- Head near midline of body
- Tail extends to left and touches spleen
- Endocrine tissues have pancreatic islet that produce insulin and glucagon
- Exocrine tissues produce digestive enzymes
pancreas
breakdown of food occurs in stomach and mouth
digestion
moves food through digestive tract includes swallowing and peristalsis
propulsion
primarily in duodenum and jejunum of small intestine
absorption
elimination of waste in the form of feces
defecation
_____split into disaccharides by salivary and pancreatic amylases
Polysaccharides
____ broken down into monosaccharides by disaccharidases on surface of intestinal epithelium
Disaccharides
___ is absorbed by cotransport with Na+ into intestinal epithelium
Glucose
____ is carried by hepatic portal vein to liver and enters most cells by facilitated diffusion
Glucose
- Bile salts emulsify lipids
- Lipase breaks down lipids which form micelles
- Micelles are in contact with intestinal epi. and diffuse with cells where they are packaged and released into lacteals
- Lipids are stored in adipose tissue and liver
liver digestion
- Proteins are split into polypeptides by enzymes secreted by stomach and pancreas
- Peptides and amino acids are absorbed into intestinal epi. cells
- Amino acids are actively transported into cells (help from GH and insulin)
- Amino acids used to build new proteins
protein digestion
- ___ can move across intestinal wall in either direction
- Depends on osmotic conditions
- 99% of ____entering intestine is absorbed
Water
____ are actively transported across wall of small intestine
Minerals