Digestive System Topic for Lecture Exam 4

Trace the path of food beginning at the mouth and ending at the anus.

Food travels through the following path: Mouth → Pharynx → Esophagus → Stomach → Small Intestine (duodenum → jejunum → ileum) → Large Intestine (cecum → ascending colon → transverse colon → descending colon → sigmoid colon) → Rectum → Anus.

List all the organs of the digestive system

• Mouth

• Pharynx

• Esophagus

• Stomach

• Small Intestine

• Large Intestine

• Rectum and Anus

• Accessory Organs

  • Salivary glands

  • Liver:

  • Gallbladder

  • Pancreas

Describe the mouth of the digestive system and it’s function.

Begins mechanical digestion (chewing) and chemical digestion with saliva.

Describe the Pharynx of the digestive system and it’s function.

Transports food from mouth to esophagus.

Describe the Esophagus of the digestive system and it’s function.

Moves food to the stomach via peristalsis.

Describe the Stomach of the digestive system and it’s function.

Secretes acid and enzymes for protein digestion; churns food into chyme.

Describe the Small Intestine of the digestive system and it’s function.

Digests and absorbs nutrients; consists of duodenum, jejunum, and ileum.

Describe the Large Intestine of the digestive system and it’s function.

Absorbs water and electrolytes; forms and stores feces.

Describe the Rectum and Anus of the digestive system and it’s function.

Stores and eliminates feces.

Describe the Salivary glands of the digestive system and it’s function.

Produce saliva to begin carbohydrate digestion.

Describe the Liver of the digestive system and it’s function.

Produces bile to emulsify fats.

Describe the Gallbladder of the digestive system and it’s function.

Stores and concentrates bile.

Describe the Pancreas of the digestive system and it’s function.

Produces digestive enzymes and bicarbonate.

Define mechanical and chemical digestion. Where does each occur in the digestive tract?

• Mechanical digestion: Physical breakdown of food (e.g., chewing in the mouth, churning in the stomach).

• Chemical digestion: Breakdown of food by enzymes and chemicals (e.g., salivary amylase in mouth, pepsin in stomach, pancreatic enzymes in small intestine).

Describe peristalsis and where it occurs in the digestive tract.

Peristalsis is the wave-like contraction of smooth muscle that propels food through the digestive tract. It occurs in the esophagus, stomach, small intestine, and large intestine.

Identify the 4 walls of the digestive tract

Mucosa, Submucosa, Muscularis externa, and Serosa (or adventitia)

The types of tissue found in the Mucosa wall of the digestive tract.

Epithelium, lamina propria (connective tissue), muscularis mucosae.

The types of tissue found in the Submucosa wall of the digestive tract.

Connective tissue with blood vessels, nerves, and glands.

The types of tissue found in the Muscularis externa wall of the digestive tract.

Smooth muscle (inner circular and outer longitudinal layers).

The types of tissue found in the Serosa (or adventitia) wall of the digestive tract.

Outer connective tissue layer (serosa in peritoneal cavity; adventitia outside it).

Where are the three salivary glands (parotid, sublingual, and submandibular) located? Which one is the largest? What is the substance produced and secreted by these glands?

• Parotid: In front of and below the ear (largest).

• Submandibular: Beneath the jaw.

• Sublingual: Under the tongue.
  All three secrete saliva, which contains salivary amylase (begins starch digestion), mucus, and antimicrobial enzymes.

List the four different types of teeth & their functions.

• Incisors – Cutting.

• Canines (cuspids) – Tearing.

• Premolars (bicuspids) – Crushing and grinding.

• Molars – Grinding.

Where is the pharynx located and what is its function?

The pharynx is located at the back of the throat and connects the nasal and oral cavities to the esophagus and larynx. It functions as a passageway for both air and food.

What is the function of the epiglottis during the digestive process?

The epiglottis is a flap that covers the larynx during swallowing, preventing food from entering the airway.

Describe the 4 histological layers of the GI tract.

Same as question 5 (mucosa, submucosa, muscularis externa, and serosa/adventitia), with specialized structures in each region (e.g., villi in small intestine mucosa).