DIGESTIVE SYSTEM

Digestive system

Is a group of organs that work together to ingest food, break down into simpler substances, and eliminate undigested waste

Oral cavity

Mouth

Mouth

Serves as the primary entry point for both the digestive and respiratory systems

Stomach

Stores, mixes, and breaks down food

Chyme

Stomach uses strong muscular layers to churn, squeeze, and grind solid food into a semi-liquid paste called

Cardiac sphincter

Connects the esophagus to the stomach

Pyloric sphincter

Connects the stomach to the small intestine

Pharynx

A hollow, muscular tube that starts behind the nose and opens into the larynx and esophagus

Esophagus

A muscular, fibromuscular tube that carries food, liquids, and saliva from the pharynx (throat) down to the stomach as part of the digestive system

Small inestine

Completes food digestion and absorbs the vast majority of nutrients and water

Rectum, feces

Temporarily store solid waste __ until the body is ready to eliminate it through the anal canal

Colon

Large intestine

Large intestine

It takes liquid waste left over from the small intestine and turns it into solid stool

Anus

External opening at the end of the digestive tract that controls the release of stool from the body

Salivary glands, liver, gall bladder, pancreas

What are the accessory organs in the digestive system?

Salivary glands

Exocrine organs that produce and secrete saliva into the oral cavity to initiate chemical and mechanical digestion

Liver

Acts as a chemical factory and filtration center in the digestive system by producing bile for fat breakdown, processing nutrient-rich blood from the gut, and regulating blood sugar

Gall bladder

Stores, concentrates, and releases bile produced by the liver to help digest and absorb fats in the small intestine

Pancreas

Aids the digestive system by producing enzyme-rich fluid daily to break down proteins, fats, and carbohydrates

Fishes

Simple digestive tract, carnivores have shorter intestines

Amphibians

Digestive tract adapted for both aquatic and terrestrial feeding

Reptiles

More developed stomach and intestines, slower digestion

Birds

Possess a crop for food storage and a gizzard for grinding food

Crop

Food storage of birds

Gizzard

For birds to grind their food

Mammals

Highly specialized teeth and digestive tracts

Ingestion

Taking in food

Digestion

Breaking food into smaller molecules

Absorption

Food enter the bloodstream

Metabolism

Nutrient processing

Assimilation

Cells absorbed nutrients

Egestion

Removal of undigested food

Mouth

The breakdown activities begin in the __ and is completed in the small intestine

Small intestine

The breakdown activities begin in the mouth and is completed in the __

Small intestine

After completion, its major function is to reabsorb water

Anus

The undigested food that remains in the tract leaves the body through the __ as feces

Feces

The undigested food that remains in the tract leaves the body through the anus as __

Liver

Is considered a digestive organ because the bile it produces helps to break down fats

Pancreas

Delivers digestive enzymes to the small intestine, has both endocrine and digestive functions

Islets of langerhans

The pancreas has endocrine functions __

Insulin

Lowers blood sugar levels

Glucagon

Raises blood sugar levels

Somatostatin

Inhibits release of insulin and glucagon

Pancreatic juice to small intestine

The pancreas has digestive functions

Amylase

Digests carbohydrates

Lipase

Digests fats

Protease

Digest proteins

Alimentary canal

Gastrointestinal tract

Alimentary canal/gastrointestinal tract

Is a continuous, coiled, hollow muscular tube that winds through the ventral body cavity from mouth to the anus

Bolus

Mass of food that has been chewed in the mouth

Mouth

A mucous membrane-lined cavity

Oral cavity

Mouth for animals

Mouth

Food enters the digestive tract through this

Labia

Lips

Lips/labia

Protect its anterior opening

Cheeks

This forms the lateral walls of the mouth

Soft palate

This forms the posterior roof of the mouth

Hard palate

Forms the anterior roof of the mouth

Tongue

Occupies the floor of the mouth

Oropharynx

Posterior to the oral cavity

Pharynx

From the mouth, food passes posteriorly into the oropharynx

Laryngopharynx

Continuous with the esophagus inferiorly

Oropharynx and Laryngopharynx

Both are passageways of food, fluid, and air

Gullet

Esophagus

Esophagus/gullet

Runs from the pharynx through the diaphragm to the stomach

Esophagus/gullet

It serves as passageway of food down to the stomach

Mucosa, submucosa, muscularis externa, serosa

The walls of the esophagus contains:

Mucosa

Innermost layer

Submucosa

Beneath the mucosa

Muscularis externa

Muscle layer made up of inner circular layer and outer longitudinal layer

Serosa

Outermost layer

Stomach

C-shaped is on the left side of the abdominal cavity, nearly hidden by the liver and the diaphragm

Cardia, fundus, body

What are the regions of the stomach?

Cardia, cardioesophageal sphincter

Posterior near the heart, surrounds the __

Fundus

Expanded part of the stomach

Body

Mid-portion of the body which contains the greater curvature and the lesser curvature

Small intestine

Is the body’s major digestive organ

Small intestine

It is a muscular tube extending from the pyloric sphincter to the large intestine

Duodenum, jejunum, ileum

Divisions of the small intestine

Small intestine

Chemical digestion begins here

Enzymes

Produced in the pancreas which are delivered to the duodenum through pancreatic ducts where they complete the chemical breakdown of food

Duodenum

Enzymes that are produced in the pancreas are delivered to the __ through pancreatic ducts where they complete the chemical breakdown of food

Pancreatic ducts

Enzymes that are produced in the pancreas are delivered to the duodenum through __ where they complete the chemical breakdown of food

Pancreas

Enzymes that are produced in the __ are delivered to the duodenum through pancreatic ducts where they complete the chemical breakdown of food

Bile

Formed by the liver enters the duodenum through the bile duct

Liver

Bile formed by the __ enters the duodenum through the bile duct

Bile duct

Bile formed by the liver enters the duodenum through the __

Duodenum

Bile formed by the liver enters the __ through the bile duct

Villi

Are the fingerlike projections of the mucosa

Mucosa

Villi are the fingerlike projections of the __

Large intestine, feces

Its major function is to dry out the indigestible food residue by absorbing water and to eliminate residues called __

Cecum

Is the first part of the large intestine

Appendix

Hanging from the cecum is the wormlike __

Twisted

Ideal location for bacteria

Ascending colon, transverse colon, descending colon

Three distinct regions of the large intestine

Ascending colon

Travels up to the right side of the abdominal cavity

Transverse colon

Travel across the abdominal cavity through the __

Descending colon

It turns down the left side to form __ to enter pelvis where it becomes the sigmoid colon

Sigmoid colon

It turns down the left side to form descending colon to enter pelvis where it becomes the __

Pelvis

It turns down the left side to form descending colon to enter __ where it becomes the sigmoid colon