Digestive System

Digestion

Breakdown of ingested food

Absorption

Passage of nutrients into the blood

Metabolism

Production of cellular energy (ATP)

Groups of Organs of the Digestive System

Alimentary Canal and Accessory Digestive Organ

Alimentary Canal Organs

Mouth, Pharynx, Esophagus, Stomach, Small Intestine, Large Intestine, Anus

Processes of the Mouth

Mastication, Mixing Masticated Food with Saliva, Initiation of Swallowing by Tongue, Allowing for Sense of Taste

Anatomy of Pharynx

Nasopharynx, Oropharynx, Laryngopharynx

Nasopharynx

Not part of the digestive system

Oropharynx

Posterior to the oral cavity

Laryngopharynx

Below the oropharynx and connected to the esophagus

Pharynx Function

Serves as passageway for food and air, propels food to the esophagus, food movement is by alternating contractions of the muscle layers

Peristalsis

Alternating contractions of the muscle layers during food movement in the digestive system

Muscle layers the propel food to the esophagus

Longitudinal Inner Layer, Circular Outer Layer

Esophagus

Runs from the pharynx to the stomach through the diaphragm, conducts food through peristalsis (slow rhythmic squeezing), passageway for food only

Pharynx

Respiratory System branches off of the

Stomach

Located on the left side of the abdominal cavity

Cardioesophageal Sphincter

Part of the stomach where the food enters

Stomach Functions

Acts as storage tank for food, Site of food breakdown, Chemical Breakdown of Protein, Delivers Chyme to the Small Intestine

Chyme

Processed food, mixture of food and stomach secretion

Small Intestine

Body’s major digestive organ site of nutrient absorption into the blood, Muscular tube extending from the pyloric sphincter to the ileocecal valve

Mesentery

Small intestine is suspended from the posterior abdominal wall by the ______

Subdivisions of the Small Intestine

Duodenum, Jejunum, Ileum

Duodenum

Attached to the stomach, curves around the head of the pancreas

Jejunum

Attaches anteriorly to the duodenum

Ileum

Extends from jejunum to large intestine

Large Intestine

Large in diameter but shorter than small intestine, frames the internal abdomen

Large Intestine Function

Absorption of water, Eliminates indigestible food from the body as feces, Does not participate in digestion of food, Goblet cells produce mucus to act as lubricant

Feces

The large intestine eliminates indigestible food from the body as ___

Accessory Digestive Organs

Salivary Glands, Teeth, Pancreas, Liver, Gall bladder

Salivary Glands

Saliva-producing glands

Salivary glands

Parotid Glands, Submandibular Glands, Sublingual Glands

Parotid Glands

Located anterior to the ears

Teeth

The role is to masticate food

Two sets of human teeth

Deciduous Teeth and Permanent Teeth

32

Adult Teeth

20

Teeth fully formed at the age of 2

Pancreas

Produces a wide spectrum of digestive enzymes that break down all categories of food

Duodenum

Enzymes produced by the pancreas are secreted in _____

Acidic Chyme

Alkaline fluid introduced with enzymes neutralizes _____

Endocrine products of the pancreas

Insulin and Glucagon

Liver

Largest gland in the body, located on the right side of the body under the diaphragm

4

Lobes of the liver suspended from the diaphragm and abdominal wall

Falciform Ligament

Suspends liver from the diaphragm and abdominal wall

Common Hepatic Duct

Connects the liver to the gall bladder

Bile

Produced by the cells in the liver and is stored in the gall bladder

Bile Composition

Bile salts, bile pigment, cholesterol, phospholipids, electrolytes

Bile Pigment

Mostly bilirubin from the breakdown of hemoglobin

Gall Bladder

Sac found in the hollow fossa of liver, stores bile from the liver,

Cystic Duct

Gall bladder stores bile from the liver by the way of the ____

Fatty Food

Bile is introduced to the duodenum in the presence of ____

Gallstones

Cause blockages in the gall bladder

Processes of the Digestive System

Ingestion, Propulsion, Peristalsis, Segmentation, Mechanical Digestion, Chemical Digestion

Ingestion

Getting food into the mouth

Propulsion

Moving food from one region of the digestion system to another

Peristalsis

Alternating waves of contracion

Segmentation

Moving materials back and forth to aid in mixing

Mechanical Digestion

Mixing of food in the mouth by the tongue, Churning of food in the stomach, Segmentation in the small intestine

Chemical Digestion

Enzymes break down food molecules into their building blocks, each major food group uses different enzymes

simple sugars, amino acids, fatty acids, alcohol

In chemical digestion, carbohydrates are broken to ______,__ proteins are broken into ____, fats are broken to *_____* and _________

Digestion Process Overview

Ingestion, Mechanical Digestion, Propulsion, Chemical Digestion, Absorption, Defecation