Digestive System

4 functions of digestive system

1. ingestion

2. propel food

3. absorb nutrients

4. excretion/elimination of waste

digestive track includes

• mouth

• pharynx

• esophagus

• stomach

• small intestine

• large intestine

peristalsis

smooth, sequential squeezing

segmentation occurs in the

large intestine

digestive system is basically a tube from _________ to _________

mouth/anus

accessory systems are part of the digestive system but not the:

digestive tract

list accessory organs/structures of digestive system

• teeth

• tongue

• salivary glands

• liver

• pancreas

• gallbladder

list 2 parts of oral cavity

1. vestibule

2. oral cavity proper

vestibule (oral cavity)

space between lips/cheeks and alveolar processes

list components of oral cavity

• mouth/oral cavity

• lips (labia) and cheeks

• palatine tonsils

• palate (oral cavity roof)

• tongue

tongue is involved in:

speech, taste, mastication, swallowing

the soft palate ends at the:

uvula

frenulum

cord-like structure, connective tissue band holding tissue to oral cavity

• found on lower lip, upper lip, and tongue

name for all of teeth

dentition

2 sets of teeth:

1. primary, deciduous, milk, deciduous, childhood (20)

2. permanent, secondary, adult (32)

list 4 types of teeth

1. incisors

2. canine

3. premolar

4. molar

meaning of incisor

cutting

how many incisors?

8 (4 L, 4 R, 4 central, 4 lateral)

how many canine teeth?

4

what do canine teeth do?

tearing

what do molars do?

grinding (millstone)

list the features of a tooth from superior to inferior

1. crown

2. neck

3. root

what is in the middle of a tooth?

pulp chamber/root canal

• includes blood and nerve suppy

enamel is only associated with the ________ of the tooth

crown

list structures of tooth from inner to outer

pulp chamber, dentin, cementum, enamel

3 pairs of salivary glands

1. parotid

2. submandibular

3. sublingual

what 4 things is saliva composed of?

1. ions (K+, Na+)

2. IgA (helps with localized immune response)

3. mucin (lubricant)

4. salivary amylase (breaks down simple carbs)

largest pair of salivary glands

parotid

smallest pair of salivary glands

sublingual

salivary gland that produces the most saliva

submandibular

location of sublingual salivary gland

under tongue

sublingual salivary gland

• smallest

• under tongue

• 3-5% of saliva

parotid salivary gland

• largest

• anterior to cheek, side of cheek

• 25-35% of saliva

submandibular salivary gland

• produces most saliva

• under angle of mandible

list pairs of salivary glands in order of decreasing size

1. parotid

2. submandibular

3. sublingual

which parts of the pharynx are involved in the digestive system?

• oropharynx

• laryngopharynx

deglutition

swallowing

3 phases of deglutition

1. initiation (tongue- voluntary)

2. pharyngeal (involuntary- skeletal muscle contraction, sequential contraction of pharyngeal constrictors)

3. esophageal (smooth muscle- peristalsis- involuntary)

function of esophagus

transfers bolus from pharynx to stomach, where it becomes chyme

• muscular tube that expands and contracts

name for bolus when it is in stomach

chyme

where are the upper and lower sphincters located?

top and bottom of esophagus

the bolus travels through the esophagus and enters the __________ region of the stomach

cardiac

after the cardiac region, the bolus travels to the rounded dome of the stomach known as:

fundus

what is between the fundus and pylorus?

body (of stomach)

most inferior region of stomach

pylorus

what is between the pylorus and the duodenum?

pyloric sphincter

4 regions of stomach

1. cardiac

2. fundus

3. body

4. pyloric

2 openings of stomach

1. gastroesophageal/cardiac (esophagus)

2. pyloric (duodenum)

purpose of gastric folds/rugae

increase surface area of stomach

layers of stomach histology from outer to inner

1. serosa/visceral peritoneum

2. muscularis

   • outer longitudinal

   • middle circular

   • inner oblique

3. submucosa (nerves & vessels)

4. mucosa

primary role of small intestine

ingestion & absorption of nutrients 90%

3 subdivisions of small intestine

1. duodenum

2. jejunum

3. ileum

end of small intestine

ileum

site of most chemical digestion and absorption

jejunum

what part of the small intestine puts chyme into solution with digestive juices?

duodenum

what increases surface area for absorption in small intestine?

transverse folds & small projections

function of intestinal juices

moisten acidic chyme, help buffer acids, hold enzymes and products of digestion in solution

the liver is an __________ organ

accessory

function of liver

add digestive juices to chyme

list lobes of liver

1. major (L/R)

2. minor (caudate/quadrate— only in R lobe)

what divides left and right lobe of the liver?

round ligament

L/R hepatic ducts merge to form:

common hepatic duct

left and right hepatic ducts come from:

left & right liver lobes

common hepatic duct & cystic duct merge to form:

common bile duct

gall bladder drains into

cystic duct

main pancreatic duct & common bile duct go to the:

hepatopancreatic ampulla

main pancreatic duct

travels across pancreas, ending in hepatopancreatic ampulla

what fluid does the common bile duct contain?

fluid from liver & gall bladder

function of gall bladder

emulsifies fat

what drains the gall bladder?

cystic duct

opening into duodenum from hepatopancreatic ampulla

major duodenal papilla

3 regions of pancreas

1. head

2. body

3. tail

what organ is the pancreas tail by?

spleen

location of pancreas

posterior to stomach

which side of the body is the pancreas head on?

right

is the pancreas an endocrine or exocrine gland?

both

endocrine functions of pancreas

pancreatic islets produce insulin and glucagon

exocrine functions of pancreas

acini produce digestive enzymes

small intestine starts with the __________ at the pyloric section of the stomach

pyloric sphincter

digestive juices from the liver, gallbladder, and pancreas are added at the:

hepatopancreatic ampulla

3 parts of small intestine

1. duodenum

2. jejunum

3. ileum

end of small intestine

ileo-cecal junction/sphincter (at cecum)

4 parts of large intestine/colon

1. ascending

2. transverse

3. descending

4. sigmoid/rectal

what divides the portions of the large intestine/colon?

right (hepatic) and left (splenic) colic flexures

where does the veriform appendix protrude from?

cecum

haustra and tenia coli function

assist with movement and absorption of bolus

haustra

bubbles of large intestine

• segmentation

tenia coli

line of smooth muscle along length of large intestine

• peristalsis

polyp

abnormal growth inside colon