Digestive System

Identify the structures that chyme will pass through, starting with the small intestine and ending with elimination.

1. Ileocecal junction 2. Cecum 3. Colon 4. Rectum 5. Anal canal

Place the events of the cephalic phase of gastric regulation in order beginning from initiation of the cephalic phase.

1. Taste or smell of food 2. Stimulation of medulla oblongata 3. Parasympathetic impulses carried by vagus nerve to neurons of enteric plexus. 4. Postganglionic neurons stimulate secretion of gastrin and histamine. 5. Gastric secretions are released.

The muscularis of the stomach consists of ______ layers.

3

The hepatic lobule is a _____ -sided structure with a(n) _____ triad at each corner and a central vein located in the center of each lobule

6, portal

Describe a hepatic lobule.

A hexagon-shaped tissue with a portal triad at each corner

Describe the cecum.

A rounded pouch located at the proximal end of the large intestine

Pepsinogen

Active form aids in breaking proteins into smaller peptide chains.

Digestion

Breakdown of large organic molecules into their component parts

Identify the substances that aid in the chemical digestion of proteins.

Carboxypeptidase Pepsin Trypsin Peptidases

Submucosa

Consists of a thick layer of connective tissue containing nerves, blood vessels, lymphatics and glands

Serosa

Consists of a thin layer of connective tissue and simple squamous epithelium

Mucosa

Consists of an epithelial lining, a layer of connective tissue referred to as lamina propria and a thin layer of muscle

Pyloric sphincter

Controls passage of food from stomach to small intestine

Hydrochloric acid

Destroys ingested bacteria and activates pepsin

Identify the secretions of the small intestine.

Disaccharidases Mucus Secretin Cholecystokinin Peptidases

Identify the components of pancreatic juice

Enzymes to digest nucleic acids Enzymes to digest proteins Enzymes to digest carbohydrates Enzymes to digest lipids Bicarbonate ions

Identify the functions of hydrochloric acid in the stomach.

Inactivates salivary amylase Activates pepsin Destroys ingested bacteria

Identify the functions of the liver.

Interconversion of nutrients Storage of glycogen, lipids, vitamins and minerals Phagocytosis Synthesis of new molecules Production of bile

What is the function of HCO3- when it is secreted by the large intestine?

It increases the pH of the feces, which are acidic because of bacterial secretions.

Identify the organs of the digestive system that are considered accessory organs.

Liver Gall bladder Pancreas Salivary glands

Identify the structures of the digestive tract that are lined with stratified squamous epithelium.

Mouth Anal canal Esophagus Oropharynx

Propulsion

Movement of food from one end of the digestive tract to the other

Absorption

Movement of molecules from the digestive tract into the circulation or lymphatic system

Secretions of the stomach

Pepsinogen Gastrin Hydrochloric acid Mucus Intrinsic factor

Mastication

Process by which teeth break food into smaller particles to increase the total surface area

Identify the functions of mucus secretion in the large intestine.

Protects intestinal lining Helps fecal matter stick together Lubricates colon wall

Identify the effects of aging on the digestive system.

Reduction in motility Thinning of tooth enamel Decrease in mucus production

Stimulation of pancreatic juice

Secretin Vagus nerve Cholecystokinin

Name the outermost or most superficial layer of the organs in the digestive tract

Serosa Adventitia

Gastrin

Stimulates gastric secretions

Identify the structures of the digestive tract that are lined with simple columnar epithelium.

Stomach Large intestines Small intestines

True or false: Both nervous and chemical mechanisms play an important role in regulating the digestive system.

TRUE The movement, secretion, absorption and elimination of food is determined by both nervous and chemical mechanisms.

True or False: Villi and microvilli of the small intestine serve to increase surface area to allow for greater digestion and absorption.

TRUE villi and microvilli always increase surface area

Ingestion

The intake of solid or liquid food into the stomach

How does the muscularis of the stomach differ from the muscularis of the majority of the alimentary canal?

The stomach has 3 layers of muscle in the muscularis and the majority of the digestive tract only has 2 layers of muscle.

Muscularis

Throughout most of the digestive tract, this tunic consists of two layers of smooth muscle: an inner circular layer, and an outer longitudinal layer

The salivary glands, tonsils, liver, gall bladder, and pancreas are _________ _________ of the digestive system

accessory organs

Identify the major neurotransmitters that regulate the digestive system.

acetylcholine norepinephrine serotonin

The majority of ion absorption occurs as a result of _____.

active transport

Intrinsic factor

aids in the absorption of vitamin B12

Largest part of stomach

body

The large intestine consists of the _____, and the anal canal.

cecum, colon, rectum

The taste, smell, or thought of food stimulates gastric secretions by activating the ______ phase of gastric regulation.

cephalic

nuclease

chemical digestion of DNA and RNA

lipase

chemical digestion of fats

amylase

chemical digestion of polysaccharides

proteolytic enzymes

chemical digestion of proteins

The semi-fluid material within the stomach that is a mixture of ingested food and gastric secretions is called

chyme

The submucosa consists of ______ tissue.

connective

Identify the duct leading from the gallbladder.

cystic duct

Feces are eliminated from the body by the process of

defecation or elimination

The tongue, oropharynx and mouth are all involved with swallowing or

deglutition

Place the segments of the small intestine in the order of which food travels.

duodenum Jejunum ileum

The process by which bile salts transform large lipid droplets into much smaller lipid droplets is called

emulsification

The majority of nervous stimulation of the digestive system comes from the _______.

enteric nervous system

The ____________ sphincter is between the esophagus and the stomach and the _____________ sphincter is between the stomach and the small intestine.

esophageal/cardiac, pyloric

The structure within the mediastinum, anterior to the vertebrae and posterior to the trachea is the

esophagus

During stomach filling the rugae _______.

flatten and allow the stomach to increase in volume

Rounded superior portion of stomach

fundus

The saclike structure on the inferior surface of the liver is the

gallbladder

Identify the parts of the pharynx that function in digestion

laryngopharynx oropharynx

The largest internal organ of the body is the

liver

Identify the strong and infrequent peristaltic contractions that move contents longer distances within the large intestine.

mass movements

The esophagus is in the ______.

mediastinum

The movements of the small intestine include segmental contractions which ______ intestinal contents and peristaltic contractions which ______ intestinal contents.

mix, propel

Identify the primary products of the chemical digestion of lipids.

monoglycerides fatty acids

Chemical digestion of starch due to secretion of enzymes occurs in the ______.

mouth small intestine

Identify the part of the pharynx that does not typically function in digestion.

nasopharynx

Select the mechanisms that regulate the digestive system.

nervous mechanisms chemical signals

Acetylcholine, norepinephrine and serotonin are ______ that affect digestive tract ______.

neurotransmitters; motility

Cardiac sphincter

opening from the esophagus to the stomach

Identify the structures that are involved in deglutition.

oropharynx tongue esophagus

Identify the organ that consists of a head located within the curvature of the duodenum and a tail that extends to the spleen

pancreas

Lipases are secreted by

pancreas

The majority of lipase is secreted by the _____.

pancreas

Identify the structures that secrete lipase

pancreas lingual glands

Identify the types of movements that occur within the small intestine.

peristalic contractions segmental contractions

Mucous

protects stomach lining

Funnel shaped part of stomach

pyloric part

The adventitia or ____________ is the outermost layer of structures in the digestive system.

serosa

The abdominal cavity is lined by ______________ which produce a thin, lubricating film.

serous membranes

Secretin, cholecystokinin, and peptidases are secretions of the ______.

small intestine

The majority of lipid digestion occurs in the ______.

small intestine

The chemical digestion of the disaccharides occurs in the ______.

small intestine Reason: Starch is broken down into disaccharides in the mouth, but the chemical digestion of disaccharides does NOT occur until the disaccharides reach the small intestine.

Cholecystokinin, secretin and the vagus nerve all ______ the release of pancreatic juices.

stimulate

Identify the organ of the digestive system that primarily functions as a storage and mixing chamber.

stomach

Intrinsic factor is secreted by the organ called the

stomach

Identify the structures where lipid digestion occurs.

stomach small intestine

The layer of the digestive tract that consists of connective tissue containing nerves, blood vessels, lymphatic vessels, small glands, and a network of nerve cells is the

submucosa

Bicarbonate ion

to raise pH of small intestine

True or False: Throughout the digestive tract, the muscularis consists of 2 layers of muscles, except the stomach, which has 3 layers.

true

True or False: Water absorption in the small intestine occurs as a result of osmosis.

true

Identify the features of the small intestine that function to increase surface area and thus enhance digestion and absorption.

villi microvilli circular folds