Digestive Organs and Their Functions

Study Notes

Accessory Organs

Assist in digestion, absorption of nutrients, and waste elimination.

Digestive Tract - Digestive Organs

Mouth:
- Lips and cheeks aid in chewing and swallowing.
- Tongue is a muscular organ with taste buds:
  - Filiform papillae: Provide texture and grip.
  - Fungiform papillae: Sensory receptors for taste.
  - Vallate papillae: Large, mushroom-shaped for taste perception.
  - Foliate papillae: Located on the sides of the tongue, contribute to taste.
- Salivary glands:
  - Parotid: Secretes serous saliva, rich in enzymes.
  - Sublingual: Produces mucous saliva, for lubrication.
  - Submandibular: Secretes mixed saliva, containing both serous and mucin.
- Teeth:
  - Deciduous (baby) teeth: 20 teeth that are replaced by permanent teeth.
  - Permanent (adult) teeth: 32 teeth, designed for specific functions.
    - Incisors: Cutting.
    - Canine: Tearing.
    - Premolars: Grinding.
    - Molars: Crushing.
  - Dental formula: 2I, 1C, 2PM, 3M for one quadrant of the mouth.
  - Tooth structure: Crown, neck, root.
- Tooth/Gum Disease:
  - Dental Caries (tooth decay): Destruction of tooth enamel due to bacteria.
  - Gingivitis: Inflammation of the gums.
  - Periodontitis: Inflammation and destruction of the tissues surrounding teeth.
Tonsils:
- Palatine and lingual tonsils are part of the immune system, protecting against infection.
- Tonsillitis: Inflammation of the tonsils.
Pharynx:
- Oropharynx and laryngopharynx are involved in swallowing.
- Deglutition (swallowing):
  - Epiglottis covers the glottis to prevent food entry into the trachea.
  - Soft palate covers the nasopharynx, blocking food from entering the nasal cavity.
Esophagus:
- Muscular tube that propels food to the stomach via peristalsis.
- Gastroesophageal (cardiac) sphincter controls food movement into the stomach.

Stomach

Areas:
- Cardia: Entrance of the esophagus.
- Fundus: Dome-shaped region.
- Body: Main central region.
- Pylorus: Lower region containing the pyloric sphincter.
Histology:
- Rugae: Folds of the mucosa, increasing surface area for absorption.
- Gastric pits/glands:
  - Mucous (neck) cells: Secrete mucus, protecting the stomach lining.
  - Parietal cells: Produce HCl and intrinsic factor (vitamin B12 absorption).
  - Chief cells: Secrete pepsinogen (inactive form of pepsin, a protein-digesting enzyme).
  - Enteroendocrine cells: Secrete hormones like gastrin.
Gastric juice: Contains pepsin and HCl, crucial for digestion.

Energy Balance

Obesity: Body weight exceeding 20% of "ideal" weight.
BMI (Body Mass Index): Measures body fat based on height and weight.
Metabolic Rate: Rate at which the body uses energy.
- Basal Metabolic Rate (BMR): Energy expenditure at rest.
- Total Metabolic Rate (TMR): Total daily energy expenditure.

Temperature and Heat Exchange

Hypothalamus: Regulates body temperature.
Heat Exchange Mechanisms:
- Radiation: Heat transfer without direct contact.
- Conduction: Heat transfer through direct contact.
- Convection: Heat transfer through fluid movement.
- Evaporation: Heat loss through sweat.

Description

This quiz explores the accessory and digestive organs involved in the digestive process, focusing on their roles in digestion, nutrient absorption, and waste elimination. You'll learn about the mouth's structure, including the different types of papillae on the tongue and the functions of various salivary glands. Test your knowledge on the anatomy and physiology of these vital organs.