Digestive System Flashcards

Organ Systems

The Body Systems

The Human Body Systems

Digestive System

Function

• Mechanical and chemical breakdown of food into small components

• Overview of Processes:

  • Ingestion

  • Digestion

  • Absorption

  • Elimination

• The entire process takes approximately 24-72 hours.

Parts of the Digestive System

Mouth

• Teeth: Aid in mechanical digestion by chewing food.

• Saliva:

  • Moistens and softens food.

  • Contains digestive enzymes:

    • Amylase: Helps break down starch.

    • Lipase: Helps break down fats.

  • Produced by 3 pairs of salivary glands in the mouth.

• Tongue:

  • Muscular organ with taste buds to assess food.

  • Moves food towards the throat.

• Pharynx:

  • Part of the throat that pushes food into the esophagus.

  • Epiglottis: Covers the larynx during swallowing to prevent food from entering the respiratory system, thus preventing choking.

Esophagus

• Muscular tube that carries food/liquids from the mouth to the stomach.

  • Lined with mucous.

• Peristalsis: Rhythmic contraction of muscles that pushes food downwards.

• Sphincters:

  • Upper sphincter opens during swallowing.

  • Lower sphincter connects to the stomach through a hole in the diaphragm and prevents stomach acid from entering the esophagus (prevents ‘heartburn’).

Stomach

• Connects to the esophagus (above) and the duodenum of the small intestine (below).

• Chemical Digestion:

  • Uses hydrochloric acid.

  • Pepsin enzyme (protein digestion).

• Mechanical Digestion:

  • Peristalsis causes mechanical churning of food with acid.

Small Intestine

• A 4-meter tube connected to the stomach; receives partially digested food.

• Bile is mixed in to reduce the acidity of contents.

• Nutrient Absorption:

  • Food travels for approximately 5 hours, allowing nutrients and minerals to be absorbed by the intestinal wall.

  • Villi: Protruding structures lining the intestinal wall that increase the surface area to enhance absorption capacity into the bloodstream.

Large Intestine

• A 1.5-meter tube through which food passes over 12 hours.

• Water is absorbed.

• Wastewater is processed by the kidneys and excreted via the urinary system (ureter to bladder to urethra).

• Semi-solid waste (feces) travels through the colon to the rectum and leaves through the anus.

Accessory Organs

Liver

• Receives blood from the stomach and intestines.

• Processes and breaks down blood, balances it, and creates nutrients the body can use.

• Detoxifies poisons consumed during metabolism.

• Metabolizes proteins and sugars and turns fats to cholesterol.

• Produces bile, which is stored in the gallbladder.

Pancreas

• Secretes insulin when blood sugar is high, moving it for use in muscles.

• Produces juice that contains enzymes for digesting fat and protein.

Gallbladder

• Stores bile, which helps break down fats.

Diseases of the Digestive System

Gallstones

• Hardened deposits of digestive fluid.

• Caused by too much cholesterol in your bile.

• Vary in size - from a grain of rice to a golf ball.

Crohn's Disease

• A type of inflammatory bowel disease.

• Chronic condition.

• Inflammation of the digestive tract.

• Believed to be caused by the immune system mistakenly attacking healthy cells.

Irritable Bowel Syndrome (IBS)

• Affects the large intestine.

• The colon tends to contract more than in people without IBS.

• Presents as abdominal pain and cramps.

• Most common in late teens to early 40s.

• Triggered by certain foods or medications.

Systems Working Together

• Skeletal: Provides nutrients for bone growth and repair.

• Circulatory: Blood takes broken-down nutrients and transports them to various places in the body.

• Muscular: Smooth muscles push food and broken-down food through the digestive system.