Quick review of digestive system and accessory organs.
1) Ingestion – Food enters the mouth or the Oral Cavity.
2) Mastication – Chewing action is called Mastication.
3) Digestion – Chemical process of breaking down food into smaller molecules
4) Secretion – Acids, Buffers, Enzymes and water are secreted to aid breakdown.
5) Absorption – Once broken down, nutrients are absorbed.
6) Excretion - Elimination of waste through defecation.
The oral cavity
-Lips or Labia act as doors to the oral cavity.
-Hard and soft Palates create the roof and tongue creates the floor.
-Taste, Sense of temperature and texture, manipulates food and aids in swallowing.
-Lingual Frenulum – Aids in speech, swallowing and keeping tongue intact.
-Parotid Salivary Gland- inferior and anterior to the ear. Swell when you get mumps.
-Sublingual Salivary Glands – Located under the tongue.
-Submandibular Salivary Glands- Located along the inner surface of the mandible.
Saliva contains antibodies, buffers, ions, waste products and enzymes.
Salivary Amylase (Ptyalin) – is a digestive enzyme that speeds up break down of carbohydrates.
Deciduous Teeth- First set of teeth also known as baby teeth. Age: 6months – 12years.
Incisor- Located in the front used to cut food.
Canine – Used for holding and tearing or slashing food.
Next are Cuspids and Bicuspids
Molars – Responsible for crushing and grinding.
-All teeth have a crown, neck and root. The crown is covered by a hard substance called Enamel.
-The inner part of the tooth there is Pulp which contains blood vessels and nerves.
Cementum – Soft version of bone helps in securing the Periodontal Ligament.
-gums are also known as Gingiva.
Main structure located here is the Epiglottis which blocks food from entering the trachea.
-10 inches long (25 centimeters)
-Extends from the pharynx, through the thoracic cavity and diaphragm, to the stomach.
Pharyngoesophagel Sphincter – Blocks the entrance to the Esophagus.
Peristalsis- The rhythmic contractions of muscles to move food down.
Lower Esophagel Sphincter- Also known as the cardia sphincter relaxes to let food into the stomach. Heart burn (pyrosis ) occurs when the door is inadvertently opened.