DIGESTIVE SYSTEM - ANATOMY AND TISSUES

what are the two groups of digestive organs?

- Gastrointestinal (GI) tract
- accessory organs

what are the accessory organs of the digestive system?

- salivary glands
- liver
- pancreas
- gall bladder

what is the function of saliva?

to lubricate, dissolve, and begin the chemical digestion of food that has been ingested

what is the other name for pharynx?

the throat

name 5 liver functions

1. metabolizes carbs, lipids and proteins
2. synthesizes bile used in digestion/absorption of dietary fats and cholesterol in SI
3. maintains normal blood glucose levels
4. produces blood proteins
5. stores certain vitamins/minerals until needed by the bo

what is the function of the gallbladder?

stores and concentrates bile

what is the function of the oral cavity structures?

provide a mechanism for manipulating/masticating food

describe peristalsis and its function

peristalsis: a progression of coordinated contractions and relaxation that take place in esophagus
function: propel food down the esophagus to the stomach

describe chemical digestion in the stomach

gastric juices are secreted and continue the process

what is gastric juices composed of?

water, digestive enzymes, hydrochloric acid

describe mechanical digestion in the stomach

macerates and mixes gastric juices w/ food changing it to chyme and propels chyme forward into duodenum of the SI

function: pancreatic juice

includes digestive enzymes for digestion of carbs, proteins, nucleic acids and triglycerides in the SI

function: pancreatic bicarbonate ions

neutralize acidic chyme from the stomach

function: large intestine

to form feces/solid waste from remaining chyme and defecate

describe mechanical digestion within the small intestine

local contractions mix chyme with digestive juices

describe chemical digestion within the small intestine

chemical digestion of carbs, proteins and nucleic acids is complete

describe absorption surface within the small intestine

SI provides primary surface for absorption of above nutrients as well as vitamins, minerals and water

describe general functions of digestive system histology

tissues are specialized to promote mechanical/chemical digestion as well as nutrient absorption

describe general functions of liver and pancreas histology

important in secretion of digestive chemicals

what are the 4 layers of the GI tract from deep to superficial

mucosa, submucosa, muscularis, serosa

what is the function of the enteric nervous system?

presence of clusters of neurons (plexuses) that comprise the ENS control digestive activities

what is the function of pancreatic enzymes?

digest carbs, proteins, lipids and nucleic acids

what is the function of bicarbonate?

neutralize gastric acid in the intestine

what is primary function of large intestine mucosa?

to absorb water and secrete mucus

what is function of large intestine mucus?

to lubricate the movement of feces through the system

what is function of bile?

used to emulsify, or disperse, fat molecules

function: stratified squamous epithelium that lines the esophagus

protect the esophagus from abrasion (wearing away) from food particles

function: muscularis layers of esophagus

provide a propulsive movement (peristalsis) that moves food into stomach

what functions are served by the stomach mucosa? (3)

1) secrete enzymes and gastric acid to promote digestion
2) hormones to regulate digestive activities
3) copious amount of mucus to provide water for digestion as well as protection from gastric acid

function: stomach muscularis

provides movements to mix food and propel resultant chyme to the SI

what is the primary function of the SI?

primary digestive organ responsible for most digestion and absorption of nutrients

what is the function of mucosa of SI

1) cells within secrete mucus and hormones
2) the mucosa is specially designed to enhance absorption by the formation of villi