Exam 3 - Digestive System Flashcards
List the 4 main functions of the digestive system.
- Intake of food
- Breakdown of food
- Absorption of nutrients
- Elimination of wastes
What are the 2 types of muscle contractions used in the digestive system?
- Peristaltic Contractions: A traveling wave of contraction in circular and smooth muscle.
- Segmentation Contractions: Non-traveling contractions that involve a wide area of the tube; the stomach uses it for “mix and mash” and the large intestine uses it for contraction of wastes to achieve water and salt extraction.
What is mastication?
The process of chewing and grinding food with you teeth.
What are the 2 functions of saliva?
- To break down food
2. Lubrication
List the events in the swallowing reflex and indicate what sensory inputs are important.
- The tongue pushes food into a ball at the back of the tongue-part of the throat
- Food is pushed into the pharynx where stretch receptors activate the swallowing reflex.
- The soft palate is pushed up to block food from being pushed into the nasal cavity.
- The larynx moves to close the glottis and block off respiratory system.
- The medulla inhibits respiration.
- The sphincter at the top of the esophagus relaxes and quickly closes.
What are the functions of the esophagus?
- The passageway to the stomach.
- There is the cardiac sphincter at the junction of the esophagus and the stomach to protect the esophagus from the acidity of the stomach.
What is the job of the stomach and how is it achieved (both mechanical and chemical)?
Goal 1: The stomach’s job is to breakdown food into a slurry acid chime by the walls secreting HCl and various digestive enzymes. (this is both chemical and mechanical)
Goal 2: Slow release from the stomach into the duodenum (as well as storage). (mechanical)
What are the stomach cell types we discussed and what do they do?
- Mucus cells: release mucus
- Chief Cells (Zymogen Cells): Secrete pepsinogen and gastric lipase.
- Parietal Cells: Secrete HCl and intrinsic factors bind to B12.
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