2 - Chewing, Swallowing, GI Secretions PPT Flashcards
Getting a taste and perhaps a hint of an aroma
What is the first step to process food for digestion and absorption?
Chewing
What does chewing food do for our GI tract?
- Decreases food size
- Lubricates food with saliva
- Forms BOLUS through mastication of teeth
What’s the first line of defense in the GI tract?
Epithelial cells
What nervous system division controls saliva secretion?
Parasympathetic
Which cranial nerves control the salivary glands (submandibular, sublingual, parotid)?
CN 7 (Facial) controls the submandibular and sublingual
CN 9 (Glossopharyngeal) controls the parotid
What is saliva composed of?
- Mostly water
- Salivary amylase to break down starch & carbs
- Sodium bicarbonate (BASIC) to maintain pH
Which muscles move the TMJ to chew?
- Temporalis
- Masseter
- Medial Pterygoid
- Lateral Pterygoid
Idea: Remember “TaMMaLe” because you chew those 🧠
Which cranial nerve innervates all four chewing muscles?
CN 5 (Trigeminal)
What two receptor types detect food once it enters the GI tract?
- Mechanoreceptors
- Chemoreceptors
Information is taken up by mechano/chemoreceptors and is set to the…
… Salivatory Nuclei in the brainstem
Saliva production is increased thanks to this information. Which two cranial nerves deliver the command to the saliva glands?
CN 7 (Facial) and CN 9 (Glossopharyngeal)
What’s the fancy shmancy scientific term for swallowing?
Deglutition
What are the three phases of swallowing?
- Oral Phase
- Pharyngeal Phase
- Esophageal Phase
“OPE” kinda sounds like “gulp” to remember the phases of swallowing
Which of these three swallowing phases is the ONLY VOLUNTARY phase?
Oral Phase
Which of the three swallowing phases takes place within the mouth?
Oral Phase
Which of the three swallowing phases takes place within the pharynx and upper esophagus?
Pharyngeal Phase
Is the Pharyngeal Phase voluntary or involuntary?
Involuntary (gotta commit now bruh)
Once receptors sense the food in the Pharyngeal Phase, where is afferent information sent?
The Swallowing Center in the Medulla
Efferent information sent back from the Swallowing Center stimulates what in the pharynx?
Muscle contraction
Muscle contraction during the Pharyngeal Phase involves which structures, and what are their actions?
Soft palate and uvula: they move upwards
Epiglottis: moves down to cover larynx
Upper Esophageal: relaxes to allow the BOLUS to slip through
Epiglottis: moves back up, uncovering larynx
When does the Esophageal Phase begin?
Begins when esophageal sphincter closes to prevent reflux
Is the Esophageal Phase voluntary or involuntary?
Involuntary
Peristalsis begins in the…
… esophagus
The goal of peristalsis in the esophagus is to…
… squeeze the BOLUS down