Biology Chapter: Digestive System

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Questions and Answers

What is the primary function of the digestive tract?

Store nutrients for later use

Produce hormones to regulate digestion

Chemically digest food

Mechanically digest food and absorb nutrients (correct)

Which of the following is NOT a major digestive gland?

Gallbladder

Liver

Esophageal gland (correct)

Pancreas

What is the function of serous cells in the digestive glands?

Absorb nutrients from food

Synthesize enzymes to digest food (correct)

Regulate hormone secretion

Produce mucus to lubricate food

What is the characteristic feature of mucous cells in the digestive glands?

Cuboidal to columnar shape with lightly stained cytoplasm Signup and view all the answers

What is the function of the liver in the digestive system?

Produce bile to digest fats Signup and view all the answers

What is the primary function of the pancreas in the digestive system?

Synthesize enzymes to digest proteins and carbohydrates Signup and view all the answers

What is the gallbladder responsible for in the digestive system?

Storing bile from the liver Signup and view all the answers

What is the general structure of the digestive glands?

Compound tubuloacinar glands Signup and view all the answers

What is the function of striated ducts?

To reabsorb sodium and excrete potassium Signup and view all the answers

What type of epithelium lines the main duct?

Stratified columnar epithelium Signup and view all the answers

Which gland has primarily serous acini?

Parotid gland Signup and view all the answers

What is the main component of the secreted products of the sublingual gland?

Mucus Signup and view all the answers

What is unique about the duct system of the sublingual gland?

It has no intercalated duct Signup and view all the answers

Which gland has the longest intercalated duct?

Parotid gland Signup and view all the answers

What is the function of mucous cells in the mixed acinus?

To secrete mucoproteins Signup and view all the answers

What is the function of myoepithelial cells?

Contraction to move secretory products and prevent distension Signup and view all the answers

Which type of cells are entirely absent in the secretory acinus of the pancreas?

Myoepithelial cells Signup and view all the answers

What is the characteristic shape of the serous cells in the pancreas?

Polarized, pyramidal shape Signup and view all the answers

What type of epithelium is found in the intercalated duct?

Simple cuboidal epithelium Signup and view all the answers

What is the function of the serous cells in the pancreas?

Producing digestive enzymes Signup and view all the answers

What is the characteristic feature of the striated duct?

Basal striations Signup and view all the answers

What type of cells can differentiate from the cells in the intercalated duct?

Both secretory cells and ductal cells Signup and view all the answers

What is the characteristic of the pancreas?

A mixed exocrine-endocrine gland Signup and view all the answers

Which of the following glands is composed of mainly mucous acini?

Sublingual gland Signup and view all the answers

What is the location of myoepithelial cells?

Inside the basal lamina surrounding acini, tubules, and the proximal ends of the duct system Signup and view all the answers

What is the function of the centroacinar cells in the pancreas?

Not specified Signup and view all the answers

What is the characteristic of the tunica in the pancreas?

A thin capsule of connective tissue Signup and view all the answers

Which of the following glands has a short duct?

Sublingual gland Signup and view all the answers

What promotes the exocytosis of digestive enzymes from secretory granules?

CCK Signup and view all the answers

What type of epithelium lines the intercalated ducts?

Simple squamous or low cuboidal Signup and view all the answers

What is the function of Secretin?

Promote water and HCO3- secretion by duct cells Signup and view all the answers

What is the primary function of the exocrine portion of the pancreas?

Producing pancreatic juice rich in digestive proenzymes Signup and view all the answers

What type of cells are more abundant in the tail of the pancreas?

Cells of the islet of Langerhans Signup and view all the answers

What is the function of glucagon?

Make energy stored in glycogen and fat release Signup and view all the answers

What is the characteristic feature of the main pancreatic duct?

High columnar with goblet cells Signup and view all the answers

How much pancreatic juice is secreted daily?

~1.5 L/day Signup and view all the answers

Study Notes

Digestive System

The digestive system consists of an open, continuous canal from the oral cavity to the anus, which mechanically digests food and absorbs nutrients.
The digestive system also includes digestive glands, which chemically digest food.

Digestive Glands

The digestive glands are composed of major and minor glands.
The major glands include:
- Major salivary glands (parotid, submandibular, and sublingual glands)
- Liver
- Pancreas
- Gallbladder
The minor glands include:
- Small salivary glands
- Esophageal glands
- Gastric glands
- Intestinal glands
The digestive glands function to chemically digest food.

Structure and Function of Pancreas

The pancreas is a mixed exocrine-endocrine gland that produces both digestive enzymes and hormones.
The pancreas has a thin capsule of connective tissue (tunica) and a parenchyma that consists of exocrine and endocrine portions.
The exocrine portion is a compound tubuloacinar gland that produces digestive enzymes.
The endocrine portion is composed of islets of Langerhans, which produce hormones such as insulin and glucagon.

Exocrine Portion of Pancreas

The exocrine portion consists of:
- Secretory acini: entirely serous cells that produce digestive enzymes.
- Centroacinar cells: small, pale-stained cells unique to the pancreas.
- Absence of myoepithelial cells.
The ducts of the exocrine portion include:
- Intercalated ducts: simple squamous or low cuboidal epithelium.
- Intralobular ducts: low cuboidal epithelium.
- Interlobular ducts: cuboidal to low columnar epithelium.
- Main pancreatic duct: high columnar epithelium with goblet cells.
The functions of the exocrine portion include:
- Producing pancreatic juice, which is a high pH fluid rich in digestive proenzymes.
- Neutralizing acidic chyme from the stomach.
- Activating enzymes to digest proteins, carbohydrates, lipids, and nucleic acids.

Endocrine Portion of Pancreas

The endocrine portion is composed of islets of Langerhans, which are rounded clusters of cells.
The cells of the endocrine portion are lightly stained, arranged in cords separated by a network of capillaries.
The cell types of the endocrine portion include:
- A cells: produce glucagon, which stimulates the release of energy from stored glycogen and fat.
- B cells: produce insulin, which promotes the uptake of glucose by cells.
- D cells: produce somatostatin, which inhibits the release of other hormones.
- PP cells: produce pancreatic polypeptide, which regulates pancreatic secretions.

Major Salivary Glands

The major salivary glands include:
- Parotid gland: a branched acinar gland that produces a serous secretion.
- Submandibular gland: a branched tubuloacinar gland that produces a mixed secretion.
- Sublingual gland: a branched tubuloacinar gland that produces a mucous secretion.
The structure of the major salivary glands includes:
- A capsule and septa (connective tissue).
- Lobules with a secretory portion and a branching duct system.
- The duct system includes intercalated ducts, striated ducts, and main ducts.

Summary of Major Salivary Glands

The parotid gland has:
- Serous acini.
- Long intercalated ducts.
- Short striated ducts.
- Secretes products containing more salivary amylase.
The submandibular gland has:
- Mixed acini, primarily serous.
- Short intercalated ducts.
- Longer striated ducts.
- Secretes products containing less amylase and more mucus.
The sublingual gland has:
- Mixed acini, mainly mucous.
- Absent intercalated ducts.
- Short striated ducts.
- Secretes products containing mainly mucus.

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Description

Learn about the digestive system, including the digestive tract and glands. Understand the components and functions of each.