WK 5 100 - A&P/NC

Digestive System Function

Breaks down food, releases, and absorbs nutrients.

Small Intestine

Primary site for digestion and nutrient absorption.

Cardiovascular System Role

Supplies oxygen and nutrients to digestive organs.

Hepatic Portal System

Veins divert blood to liver for nutrient processing.

Endocrine System Role

Hormones control digestion and nutrient metabolism.

Accessory Digestive Organs

Critical for food breakdown and nutrient assimilation.

Gastrointestinal Tract

Hollow, muscular tube for food processing.

GI Tract Length

Approximately 7.62 meters during life.

Mouth and Anus

Open to external environment, food is outside body.

Nutrient Absorption

Nutrients enter body's inner space through absorption.

Mechanical Digestion

Initiated by teeth and tongue in the mouth.

Chemical Digestion

Begins in the mouth with salivary glands.

Gallbladder Function

Stores bile for digestion in the small intestine.

Liver Function

Produces bile and processes nutrients from digestion.

Pancreas Function

Secretes enzymes essential for digestion.

Mucosa Layer

Innermost layer, produces mucus for digestion.

Epithelium Types

Non-keratinized in mouth; simple columnar in intestines.

Pharynx

Connects mouth to esophagus, part of GI tract.

Esophagus

Muscular tube transporting food to stomach.

Stomach

Mixes food with digestive juices for breakdown.

Large Intestine

Absorbs water and forms waste for excretion.

Digestive System Cooperation

Works with other systems for overall body function.

Simple columnar epithelium

Type of tissue lining stomach and intestines.

Goblet cells

Secrete mucus and fluid into the lumen.

Enteroendocrine cells

Release hormones into interstitial spaces.

Rapid renewal of epithelial cells

Epithelial cells renew every few days to a week.

Lamina propria

Contains connective tissue, blood, and lymphatic vessels.

Mucosa-associated lymphoid tissue (MALT)

Clusters of lymphocytes providing immune functions.

Peyer's patches

Immune defense structures in the distal ileum.

Muscularis mucosa

Thin muscle layer creating folds in digestive organs.

Submucosa

Dense connective tissue connecting mucosa to muscularis.

Submucosal plexus

Nerve network regulating digestive secretions.

Muscularis externa

Two smooth muscle layers promoting mechanical digestion.

Myenteric plexus

Controls motility of muscular contractions in the gut.

Submucosal plexus

Regulates digestive secretions in submucosal layer.

Voluntary control regions

Skeletal muscle areas in mouth and anal sphincter.

Oblique muscle layer

Third muscle layer in stomach for churning food.

Taeniae coli

Longitudinal muscle bands forming pouches in colon.

Serosa

Outer layer of gastrointestinal tract in abdominal cavity.

Adventitia

Dense collagen fiber sheath in mouth and pharynx.

Enteric nervous system

Intrinsic nerve network from oesophagus to anus.

Sympathetic activation

Inhibits GI secretion and motility during stress.

Parasympathetic activation

Stimulates GI secretion and motility during rest.

Lacteals

Lymphatic vessels absorbing lipids from digestive tract.

Gastrointestinal tract

Continuous tube open to outside at both ends.

Celiac trunk

Supplies liver, stomach, and duodenum.

Superior mesenteric artery

Supplies remaining small intestine.

Inferior mesenteric artery

Supplies large intestine.

Hepatic portal system

Collects nutrient-rich blood from small intestine.

Peritoneum

Serous membrane sac in abdominal cavity.

Parietal peritoneum

Lines the abdominal wall.

Visceral peritoneum

Envelopes abdominal organs.

Peritoneal cavity

Space between visceral and parietal peritoneum.

Peritonitis

Inflammation of the peritoneum.

Chemical peritonitis

Caused by gastrointestinal breach allowing contents leakage.

Haemorrhagic peritonitis

Results from ruptured pregnancy or traumatic injury.

Bacterial peritonitis

Associated with infections like appendicitis.

Mortality rate of peritonitis

Current rate ranges from 30 to 40 percent.

Retroperitoneal organs

Structures located posterior to the peritoneum.

Duodenum

First portion of the small intestine.

Pancreas

Digestive organ located retroperitoneally.

Ascending colon

Part of large intestine located retroperitoneally.

Descending colon

Part of large intestine located retroperitoneally.

Rectum

Final section of the large intestine.

Blood supply to intestines

One-fourth of blood directed during digestion.

Peritoneal fluid

Lubricates to minimize friction between surfaces.

Mouth

Entry point for food; initiates digestion.

Pharynx

Passageway for food from mouth to oesophagus.

Oesophagus

Tube connecting throat to stomach.

Stomach

Organ that mixes food with digestive juices.

Small intestine

Primary site for nutrient absorption.

Large intestine

Absorbs water; forms feces.

Teeth

Structures that mechanically break down food.

Tongue

Muscle that aids in food manipulation and swallowing.

Salivary glands

Produce saliva to begin carbohydrate digestion.

Liver

Processes nutrients and detoxifies substances.

Pancreas

Secretes digestive enzymes and hormones.

Gallbladder

Stores bile for fat digestion.

Mucosa

Innermost layer of the gastrointestinal tract.

Submucosa

Layer containing blood vessels and nerves.

Muscularis

Layer responsible for peristalsis and segmentation.

Serosa

Outer layer of the gastrointestinal tract.

Enteric nervous system

Intrinsic nervous system regulating digestive functions.

Autonomic nervous system

Extrinsic nervous system influencing digestive activity.

Ingestion

Entry of food into the gastrointestinal tract.

Propulsion

Movement of food through the digestive tract.

Mechanical Digestion

Physical breakdown of food without chemical change.

Chemical Digestion

Breakdown of food into chemical building blocks.

Absorption

Nutrients enter bloodstream or lymphatic system.

Defaecation

Elimination of undigested materials as feces.

Gastrointestinal Tract

Organ system for food processing and digestion.

Chemical Digestion

Breakdown of food using enzymes and acids.

Absorption

Nutrient uptake into bloodstream from digestive tract.

Neural Mechanisms

Nervous system controls digestion and absorption processes.

Endocrine Mechanisms

Hormonal regulation of digestive activity and function.

Extrinsic Control

Regulation outside digestive system via autonomic nervous system.

Intrinsic Control

Regulation within digestive system via enteric nervous system.

Mechanoreceptors

Sensors detecting mechanical stimuli in digestion.

Chemoreceptors

Sensors detecting chemical stimuli, including taste.

Osmoreceptors

Sensors detecting osmotic changes in the body.