digestive

What is the primary role of the digestive system?

To break down (digest) food and absorb nutrients into the blood or lymph for cellular use.

What does the GI tract include?

Oral cavity, pharynx, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum to rectum).

What are accessory digestive organs?

Organs that secrete substances to aid digestion but food doesn’t pass through them directly, including teeth, tongue, salivary glands, liver, gallbladder, pancreas.

What is ingestion?

Taking food into the mouth.

What is propulsion in the digestive system?

Moving food through the GI tract (swallowing, peristalsis).

What comprises mechanical digestion?

Chewing, churning (stomach), segmentation (SI).

Define chemical digestion.

Enzymatic breakdown of macromolecules.

What is absorption in the context of digestion?

Transporting nutrients into blood/lymph.

What is defecation?

Elimination of undigested materials as feces.

What are the functions of teeth?

Mastication (chewing), speech, aesthetics.

What are the two types of dentitions?

Deciduous (baby teeth) and permanent teeth.

What are the layers of a tooth?

Enamel, dentin, pulp.

What is the function of salivary amylase?

Digest starch.

What is the role of the parotid gland?

Secretes salivary amylase, contributing to 25% of saliva.

What are the functions of the tongue?

Mechanical processing, assists swallowing & speech, contains taste sensors, secretes lingual lipase.

What begins the process of swallowing?

Voluntary action that becomes reflexive.

What is peristalsis?

Coordinated muscle contractions that propel contents through the GI tract.

What is segmentation?

Mixing contractions without forward movement in the small intestine.

What are the functions of the stomach?

Mechanically mixes food, begins protein digestion, secretes gastric juice, regulates chyme entry to duodenum.

What do goblet cells secrete?

Mucus.

What does gastrin stimulate?

Stimulates HCl and pepsinogen secretion.

What is the function of bile?

Emulsifies fats using bile salts.

What is the role of pancreatic juice?

Neutralizes acid and contains enzymes for digestion.

What stimulates the release of secretin?

Acidic chyme in the duodenum.

What is the effect of CCK?

Increases pancreatic enzymes and bile release, decreases hunger.

What occurs during the cephalic phase of digestion?

PSNS is triggered by smell/sight, leading to gastric secretions.

What is the primary absorbable structure in the small intestine?

Villi.

What is the function of Peyer’s patches?

Immune surveillance in the ileum.

What facilitates the absorption of fatty acids in the small intestine?

Lacteals transport them as chyle.

What nutrients does the large intestine absorb?

Water, Na+, vitamins (K, B5, B7, B9).

What are the functions of Kupffer cells?

Destroy bacteria and RBCs in the liver.

What hormone is secreted when food enters the stomach?

Gastrin.

What are the key hormones involved in appetite regulation?

Leptin (↓ appetite), ghrelin (↑ appetite), NPY.

What is the hepatic portal vein?

Carries nutrient-rich blood from the GI tract to the liver.

How much fluid enters the GI tract daily?

Approximately 9 liters.

How much fluid typically exits in stool?

Only 0.2 liters.

What aids in the absorption of vitamin B12?

Intrinsic factor.

Which vitamins are fat-soluble?

A, D, E, K.

What is gluconeogenesis?

The production of glucose from non-carbohydrate sources.

What is insulin's role during the absorptive state?

Promotes glucose uptake and lipid formation.

What happens during the postabsorptive state?

Increase in gluconeogenesis and ketone production driven by hormones like glucagon.

What is the role of the mesentery proper?

Supports the small intestine.

What mechanism primarily occurs in the jejunum?

Nutrient absorption.

What is the role of bicarbonate in pancreatic juice?

Neutralizes gastric acid in the duodenum.

Define the role of the serosa in the GI tract.

CT covering, absent in oral cavity, esophagus, and rectum.

What does VIP stand for and its role in digestion?

Vasoactive Intestinal Peptide; increases intestinal secretions and dilates capillaries.

What effect does secretin have on the pancreas?

Increases bicarbonate secretion.

What process does glucagon stimulate during fasting?

Glycogenolysis.

When is ghrelin released and what is its effect?

Released when the stomach is empty; increases appetite.

How long does the average person swallow during the day?

Approximately 2400 times.

What does the greater omentum connect?

The stomach to the transverse colon.

What is the main purpose of the intestines?

Digestion and absorption of nutrients.