What is the alimentary canal?
A hollow, irregular tube that opens at both ends, taking in food and excreting the waste
What kinds of processing does food undergo in the body?
Digestion, absorption, and metabolism
Describe the layers of the digestive tract’s wall.
Mucosa (tough, stratified, abrasion-resistant epithelium)
Submucosa (connective tissue that contains many blood vessels and nerves)
Muscularis (two layers of muscle tissue that controls peristalsis)
Serosa (outermost covering)
What is the Uvula?
What function does it perform?
Uvula - cone-shaped structure that hangs down from center of the soft palate.
- prevents food or liquid from entering nasal cavities above the mouth.
What are the four major types of teeth?
Incisors, canines, premolars, molars
What digestive enzyme is found in saliva?
Salivary amylase
What role do the pharynx and esophagus play in the digestive tract?
- Located behind the nasal cavities & mouth.
- Allows food to pass from oral cavity to esophagus.
- Esophagus is a tube that connects pharynx to stomach.
What are the sphincters at each end of the esophagus and what function do they serve in the body?
Upper esophageal Sphincter (UES) - helps prevent air from entering during respiration
Lower esophageal Sphincter/Cardiac Sphincter (LES) - prevents backflow of acidic stomach contents
What is chyme?
Semisolid mixture that food is broken down into in stomach.
How does the pyloric sphincter muscle help the stomach perform its digestive function?
Sphincter muscles assist holding food in place where it should be at any given time.
What are the main divisions of the stomach?
Fundus, body, and pylorus
What are the main divisions of the small intestine?
Duodenum
Jejunum &
Ileum
What is bile and where does it come from?
a substance that assists in breaking down or emulsifying fats.
Secreted from the Liver
What is the function of the gallbladder?
- Concentrates and stores bile produced in the liver.
- Secretes bile into small intestines once food enters the duodenum.
Why is the pancreas considered both an endocrine and exocrine gland?
Exocrine gland - secretes pancreatic juice into ducts
Endocrine gland - secretes hormones into the blood.
What is the function of the large intestine?
- Completes digestion & absorption of certain nutrients
- Produces vitamin K & some of the B complex vitamins
Name the divisions of the large intestine.
Cecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anal canal
What is the function of the appendix and where is it located in the body?
- Serves as a “breeding ground” for the non-pathogenic intestinal bacteria found throughout the colon.
- Maintaining a normal intestinal microbiome helps prevent pathogenic bacteria from becoming established.
- The appendix is attached to back of cecum & located in right lower quadrant of abdomen about 1/3rd of the way along a line from right anterior superior iliac spine to the umbilicus at an area known as McBurney’s point.
What are two prominent extensions of the peritoneum?
- Mesentery - extension between parietal & visceral layers of the peritoneum
- Greater omentum - pouch-like extension of visceral peritoneum from lower edge of the stomach, part of duodenum & transverse colon
What is the difference between mechanical and chemical digestion?
Mechanical digestion - breaks food into tiny particles through chewing, swallowing & defecation.
Chemical digestion - consists of numerous chemical reactions catalyzed by enzymes that break down large, nonabsorbable food molecules into smaller absorbable molecules.
What are the end products of carbohydrate digestion?
Carbohydrate digestion has been completed when STARCHES & double sugars have been CONVERTED mainly to GLUCOSE (monosaccharide).
What must happen to a lipid before it can be chemically digested?
- Must be emulsified by bile
- Then pancreatic lipase splits up the fat molecules into fatty acids & glycerol to be absorbed.
