The Digestive System Review Sheet Digestive System I

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The Digestive System Review Sheet

Digestive System I

1. What are the 2 main organ classifications of the digestive system? Which organs are included in each group?

  1. Alimentary canal: digests food and absorbs the digested fragments through its lining into the blood

  2. The accessary digestive organs: assist the process of digestive breakdown in various ways

2. Why is food material within the alimentary canal considered outside of the body?

  • Food material within this tube is technically outside the body, because it has contact only with cells lining the tract and is open to the external environment at both ends

3. Describe the following mouth structures:

  • Mouth: oral cavity, a mucous membrane-lined cavity

  • Lips: Labia, protect the mouth’s anterior opening

  • Cheeks: Form the mouth’s lateral wall

  • Hard palate: Forms the mouth’s anterior roof

  • Soft palate: Forms the mouth’s posterior roof

  • Uvula: A fleshy fingerlike projection of the soft palate, which extends downward from its posterior edge

  • Vestibule: The space between the lips and cheeks externally and the teeth and gums internally

4. What is the frenulum of the tongue? Which structure of the tongue contains taste buds?

  • The frenulum, a fold of mucous membrane, secures the tongue to the floor of the mouth and limits its posterior movements

  • The Papillae on the tongue containing taste buds, or taste receptors

5. How are the two layers of smooth muscle arranged on the walls of the pharynx? How does this arrangement help to propel food through the pharynx?

  • The cells of the inner layer run longitudinally

  • The cells of the outer layer run around the wall in a circular fashion

  • Alternating contractions of these two muscle layers propel food through the pharynx into the esophagus

6. What are the 4 layers of the alimentary canal organs? What are the features of each layer?

  1. The mucosa: The inner most layer, a moist membrane that lines the cavity or lumen of the organ

  2. 2. The submucosa: Is found just beneath the mucosa. It is a soft connective tissue layer containing blood vessels, nerve endings, lymph nodes and lymphatic vessels

  3. 3. The muscularis externa: A muscle layer typically made up of an inner circular layer and an outer longitudinal layer of smooth muscle cells

  4. 4. The serosa: the outermost layer of the wall. It consists of a single layer of flat serous fluid-producing cells, the visceral peritoneum

7. The alimentary canal wall contains which 2 important nerve plexuses?

  • The alimentary canal wall contains 2 important nerve plexus (a branching network of axons outside of the central nervous system): Submucosal nerve plexus and the myenteric nerve plexus

8. Locate the following structures of the stomach:

Body, Circular muscle, Duodenum, Fundus, Longitudinal muscle, Oblique muscle, pylorus, pyloric sphincter

9. What are rugae?

When its empty, it collapses inward on itself and its mucosa is thrown into large folds called rugae (roo’ge)
10. Where is the lesser omentum located? How about the greater omentum?

  • The lesser omentum is a double layer of peritoneum extends from the liver to the lesser curvature

  • The greater omentum drapes downward and covers the abdominal organs like a lacy apron

11. Which structure of the stomach produces gastric juice?

  • The mucosa of the stomach is dotted with millions of deep gastric pits, which lead into gastric glands that secrete the solution called gastric juice

12. What do the following cells produce?

  • The chief cells produce protein-digesting enzymes, mostly pepsinogens

  • The parietal cells produce corrosive hydrochloric acid

  • The mucous neck cells produce a sticky alkaline mucus, which clings to the stomach mucosa and protects the stomach wall itself from being damaged

13. What are the 3 subdivisions of the small intestine?

  • duodenum: beginning

  • Jejunum: middle

  • Ileum: terminal

14. Where is bile produced and stored? What is the function of bile?

  • Bile (produced by the liver, stored in the gallbladder) also enters the duodenum through the bile duct

15. What are the 3 structures that increase the absorptive surface of the small intestine?

  • Microvilli: tiny projections of the plasma membrane of the mucosa cell, sometimes it is referred to as the brush border

  • Villi: fingerlike projection of the mucosa

  • Circular folds: deep folds of both mucosa and submucosa layers

16. What are the 2 structures inside the villi?

  • Within each villus is a rich capillary bed and a modified lymphatic capillary called a lacteal

  • The digested food are absorbed through the mucosa cells into both the capillary and the lacteal

17. What is the major function of the large intestine?

  • Its major functions are to dry out the indigestible food residue by absorbing water and eliminate these residues from the body as feces

18. What are the subdivisions of the large intestine?

  • Cecum

  • Appendix

  • Colon

  • Rectum

  • Anal canal

19. The anal canal has an external _____________________(voluntary/involuntary) sphincter formed by __________________(skeletal/smooth) muscle and internal _____________________ _____________________(voluntary/involuntary) sphincter formed by __________________(skeletal/smooth) muscle.

  • The anal canal has an external voluntary sphincter formed by skeletal muscle and internal involuntary sphincter formed by smooth muscle

20. What are the pocket like sacs on the large intestine called?

  • The pocket like sacs on the large intestine are called haustra

The digestive system II

1. Pancreas:
a. What is the function of the pancreas?

  • The pancreas is a soft, pink, triangular gland that extends across the abdomen from the spleen to the duodenum

  • The pancreas produces a wide spectrum of enzymes that break down all categories of digestible food

b. What 2 hormones do the pancreas produce?

  • insulin and glucagon

2. Liver:
a. How many lobes does the liver have?

  • The liver has 4 lobes and is suspended from the diaphragm and abdominal wall by a delicate mesentery cord , the falciform ligament

b. What does emulsify mean?

c. Bile leaves the liver through the _____________________________________ duct and enters the duodenum through the ______________________duct.

  • Bile leaves the liver through the common hepatic duct and enters the duodenum through the bile duct

d. Explain the following bile related diseases:



Hepatitis or cirrhosis:

3. Salivary Glands:

a. What are the names of the 3 pairs of salivary glands? Where are they located?

  • The large parotid glands lie anterior to the ears

  • The submandibular glands and the small sublingual glands empty their secretions into the floor of the mouth through tiny duct

b. What are the functions of the salivary glands?

  • The mucus moistens and helps to bind food together into a mass called bolus, which makes chewing and swallowing easier

  • The clear serous portion contains an enzyme, salivary amylase, which begins the process of starch digestion in the mouth

4. Teeth:

a. Describe the following teeth that are classified according to shape and function:

  • Incisor: Chisel-shaped incisor are adapted for cutting

  • Canines: the fanglike canines are adapted for tearing or piercing

  • Premolars/ molars: have broad crowns with rounded cusps (tips) and are best suited for grinding

b. Label the following structure:

Crown, Cementum, Dentine, Enamel, Gingiva, Neck, Pulp containing blood vessels and nerves, Root, Root Canal

Functions of the digestive system

1. What are the 6 essential activities of the GI tract?

  • Ingestion

  • Propulsion

  • Physical food break down

  • Chemical food break down

  • Absorption

  • Defecation

2. What is peristalsis and segmentation?

  • Peristalsis is involuntary and involves alternating waves of contraction and relaxation of the muscles in the organ wall (primarily in the esophagus)

  • In segmentation, single segments of the intestine alternately contract and relax: the food is mixed rather than propelled along the tract

3. Where does mechanical breakdown happen in the body?

  • In the mouth by the tongue

  • In the stomach by churning

  • In the small intestine by segmentation

4. Write down the breakdown product of the following macromolecules:


5. Where is the major absorptive site in the body?

6. Which 2 nervous systems control the reflexes of the digestive activity?

7.What are the 2 phases of deglutition process? (Swallowing)

  1. The voluntary buccal phase: (occurs in the mouth) Chewing and mixing

  2. The involuntary pharyngeal-esophageal phase: Transport food through the pharynx and esophagus

8. Write down the function/ location of the following hormonal factors:

  • Gastrin: the presence of food and falling pH in the stomach stimulates the stomach to produce the hormone gastrin to help the stomach glands to produce more protein digesting enzymes

  • Hydrochloric Acid: makes the stomach contents very acid, activates pepsinogen to pepsin, the active protein digesting enzyme

a. Gastrin:

b. HCL:

c. Pepsin:

d. Brush boarder enzymes: brake down both carbohydrates and protien

e. Amylase: startch digestion

f. Secretin: cuase the liver to increase the output of bile

g. Lipase: Breaks down fat

9. What are the functions of the bacteria that live with the lumen of the large intestine?

  • metabolize some of the remaining nutrients, releasing gases

  • Produce vitamines ( vitamin K and B)

10. What are the 2 major types of propulsive movements?

  1. Colon peristalsis: sluggish and contribute very little to propulsion

  2. Mass movements: long, slow-moving but powerful contractile waves that move over large areas of the colon and force the contents toward the rectum

Nutrition and Metabolism

1. What are the major nutrients in the body?

  • Carbohydrates, lipids and proteins

  • Vitamins and minerals

  • Water

2. What are the differences between saturated fat and unsaturated fat?

3. Why is eating egg, milk and meat proteins better than eating legumes?

4. What are the 7 minerals that our body requires?

  • The body requires 7 minerals: Calcium, phosphorus, potassium, sulfur, sodium, chloride and magnesium

5. Can you find one food that contains all the required vitamins?

  • No one food contains all the required vitamin

6. What is metabolism? What are the 2 reactions involved in metabolism?



7. Define the following diseases:



8. What are some features of the liver cells?

detoxify, regenerative

9. Define the following reactions:



10. What are the functions of cholesterol? How can we get rid of cholesterol in our body?

11. What are lipoproteins? What is the difference between low-density lipoprotein and high-density lipoprotein?

Low density: transport cholesterol to the body cells

Hight density: transport cholesterol from the body cells to the liver

12. Where are carbohydrates first broken down? How about lipids? Proteins?

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