Digestive System Flashcards

Flashcards about the Digestive System

What are the main functions of the digestive system?

Ingest food, alter food, absorption, eliminate waste

What does the digestive system consist of?

A tube (alimentary canal or GI tract) and accessory structures

What do salivary glands secrete, and where?

Saliva into the oral cavity

What does the pancreas secrete, and where?

Pancreatic juice into the duodenum

What do the liver and gallbladder secrete, and where?

Bile into the duodenum

Define ingestion.

Taking food into the body

Define propulsion.

Moving food within the digestive tract via deglutition (swallowing) and peristalsis

Define mechanical digestion.

Breaking down ingested material using grinding or crushing forces like mastication (chewing) and segmentation

Define chemical digestion.

Breaking down ingested food by hydrolysis using specific enzymes

Provide an example of chemical digestion with sucrase.

Sucrase breaks down Sucrose + H2O into Glucose + Fructose

Provide an example of chemical digestion with lipase.

Lipase breaks down Lipid + H2O into Glycerol + Fatty Acids

Define absorption in the digestive system.

The transport of digested end products across the GI tract wall into the blood or lymph

Define defecation.

Elimination of solid, unabsorbed waste products

How are digestive processes regulated?

Via control mechanisms sensitive to the volume and composition of lumenal contents, regulating motility and secretions

What do mechanoreceptors in the GI tract wall monitor?

The stretch of the GI wall

What do chemoreceptors in the GI tract wall monitor?

The chemistry of the components: solute concentration (osmolarity), pH, presence of complex nutrients, and end products

Describe short reflexes in the digestive system.

No CNS involvement; controlled by intrinsic nerve plexuses and hormones produced by enteroendocrine cells

Describe long reflexes in the digestive system.

Involves the CNS

What is the function of the falciform ligament?

Binds the liver to the anterior abdominal wall and the diaphragm

What are the general functions of the tunica mucosa?

Lines the lumen, secretes mucus and enzymes, contains lymph nodes for protection, and muscle contracts to create folds increasing surface area

What are the boundaries of the oral cavity?

Anterior: lips, Lateral: cheeks, Inferior: tongue, Superior: hard palate (anteriorly) and soft palate (posteriorly), Posterior: fauces

Define vestibule in the context of the mouth.

Area between the labia and the anterior surfaces of the teeth

Define oral cavity proper.

Area between the posterior surfaces of the teeth and the fauces

What are the functions of the tongue?

Contains taste buds, mucus and serous glands; grips food, mixes it with saliva, compacts it into a bolus; articulates speech

What are the functions of Saliva?

Cleanse the mouth, solubilize chemicals in the food (taste), moistens food to form a bolus, contains amylase (carbohydrates digestion) and lingual lipase (lipids digestion)

What are the extrinsic salivary glands?

Parotid glands, submandibular gland, sublingual gland

What is the composition of saliva?

97-99.5% water; solutes: electrolytes, amylase, lingual lipase, mucin, lysozyme, IgA, wastes

What is the pH range of saliva?

6.75 – 7.00

What factors control salivation?

Thoughts/smell/sight of food, activation of chemoreceptors, presence of irritants or mechanoreceptors in the mouth small intestine and stomach