CH6 Digestive System

each accessory organ aids in

breakdown of food

primary organ of digestive system

GI tract

accessory organs of digestive system

teeth, toungue, salivary glands, gallbladder

define propulsion

movement of food through GI tract

majority of digestion and absorption occurs in

small intestine

what kind of digestion do the teeth and mouth do

mechanical

what kind of digestion: salivary glands

chemical

when food enters the SI the gallblader, pancreas, and liver do what to aid digestion

release secretions (bile, enzymes)

alimentary canal is another word for

GI tract

alimentary canal/GI tract consists of

mouth, pharynx, esophagus, stomach, small intestine, large intestine, and bootyhole

4 layers of alimentary tract

mucosa, submucosa, muscularis, serosa

the alimentary canal layers are basically made of 3 things:

mucosa, smooth muscle, connective tissues

nutrients are absorbed in the ______ or the _____

blood, lymph

The GI tract has _____ and _____ innervation

intrinsic and extrinsic

intrinsic innervation component(s):

enteric NS

extrinsic components:

sympathetic and parasympathetic

enteric NS can function ______

independently

Branch of the ANS: rest and digest

parasympathetic

Branch of the ANS: fight or flight

sympathetic

sympathetic does what to digestion

restricts

2 main functions of digestive blood vessels

1. transport the proteins and lipids absorbed by mucosal cells

2. supply nutrients to the GI organs

T/F: lipids are absorbed by cardiovascular system

F

T/F: lipids are absorbed by lymphatic system

T

lipids are absorbed by ______ (dont name the system name the specific part)

lacteals

veins that collect nutrient rich blood from the SI empty out into the

hepatic portal system

hepatic portal system

network of veins that take blood to the liver before continuing to systemic circulation

the digestive organs are held in place by the ________

peritoneum

arteries branching from abdominal aorta supply _____

alimentary canal

the celiac trunk supplies _____

liver, stomach, and duodenum

superior and inferior mesenteric arteries supply ______

small and large intestines

arteries branching off aortic arch and thoracic aorta supply ________

anterior parts of alimentary canal

nervous plexuses of the alimentary canal

meyenteric plexus and submucosal plexus

the plexuses of the GI tract are found along the:

layers of the alimentary canal

the parietal and visceral pleura are analagous to the

parietal and visceral peritonium

membrane linings of the abdomen

peritoneum

the visceral peritoneum has multiple large

folds

digestive system processes

propulsion, absorption, mech digestion, chem digestion

the digestive system is regulated by

endocrine and nervous system

function of the digestion system

absorption of nutrients into the body

T/F: one can live without a small intestine

F

esophagus

muscular tube connecting pharynx to stomach

role of sphincters in the esophagus

maintain movement of food, close off stomach

type of muscles in the esophagus

sphincters

gland of the stomach

goblet cell

deglutination

swallowing

name the phases of deglutination

voluntary phase, pharyngeal phase, esophageal phase

reigons of the stomach

cardia, fundus, body, pylorous

the secretion of gastric juice is controlled by

nervous and endocrine

3 phases of gastric secretion

cephalic, gastric, intestinal

define gastric secretion

secretion of stomach acid

cephalic involvement in gastric secretion

brain stimuli

cephalic factor that overrides gastric phase

emotional distress

what protects the stomach from digesting itself

mucosal barrier

components of the mucosal barrier

thick coat of bicarbonate rich mucus, tight junctioned epithelial cells, stem cells

types of digestion that occur in the stomach

mech and chem

2 substances that get directly absorbed by the stomach

alcohol and drugs

fundus function

stores undigested food and gas

why is the stomach mucosal layer bicarbonate rich (how does it protect from the stomach acid)

its a pH buffer

pancreas function

secrete bicarbonate ions and enzymes that catalyze chem digestion

define chyme

liquid created when food is mixed with digestive juices

salivary glands function

chem digestion of carbs, assist in swallowing/mech digestion, antibacterial

liver function

produce bile, excrete waste through bile

Bile function

emulsifys lipids so they can be digested in the small intestine

Gallbladder function

store concentrate and releases bile

gallbladder structure

muscular sac on posteriorinferior side of liver

pancreas structure

pancreatic acini: acini cells surrounding a duct

liver structure

hexagonal lobules surrounding a central vein, lobules contain hepatocytes

large intestine function

absorb water, electrolytes, vitamins

propulsion

defacation

limited secretion

Define peristalsis

alternating waves of contraction/relaxation of GI tract muscles to push food down

small intestine is divided into:

duodenum, jejeunum, ileum

the large intestine is also known as the:

colon

sections of the large intestine

ascending transverse descending sigmoid

the pancreas secretes bicarbonate to neutralize _____

chyme

deglutination involves _____ muscle

skeletal

deglutination involves the muscles of what parts

toungue, pharynx, esophagus

the pharyngeal phase of deglutination is controlled by what NS

autonomic

the esophageal phase of deglutination is controlled by what NS

autonomic

whats unique about the muscularis of the stomach

has a third layer, the oblique muscle

whats unique abt the muscularis of the large intestine

its longitudinal layer is divided into 3 segments (tena colli)

muscularis of the small intestine

2 layers of smooth muscle

muscularis of the most proximal and distal reigons of the alimentary is made of ______

skeletal muscle

layers of the mucosa

epithelium, lamina properia, muscularis mucosae

muscularis mucosae vs muscularis

muscularis mucosae is a sublayer of the mucosa, muscularis is the layer of muscle surrounding the submucosa

list layers of the alimentary canal from the lumen to the mesentery

1. mucosa

2. submucosa

3. muscularis

4. serosa

list layers of the alimentary canal from MESENTERY to the lumen

1. serosa

2. muscularis

3. submucosa

4. mucosa

reigons of the peritoneum

visceral and parietal

fluid filled space inbetween peritoneum

peritoneal cavity

what is the peritoneal cavity fluid for

prevent friction between visceral and parietal peritoneum

the visceral peritoneum has multiple large

folds

the peritoneal folds do what

envelope certain abdominal organs

peritoneal folds hold organs towards what direction

dorsal

retroperitoneal means

partially covered by peritoneum

5 major peritoneal folds

1. greater omentum

2. falciform ligament

3. lesser omentum

4. mesentery

5. mesocolon