GI 2

Question 1

Describe the mouth.

Answer 1

Mouth: entry point
- Lips, tongue, palate, teeth, salivary gland all relevant
Lips: retain food and guide it

Tongue: guiding food during chewing. Keeps food bolus under teeth and during swallowing.

- Sensory afferent from taste buds but also long loop reflexes. 
- Skeletal muscle. Voluntary contol 
- Involuntary activity: micropositioning tongue to make sure its not under your teeth

Palate: forms roof of oral cavity: separates mouth and nasal passages (so food doesn’t go into your nose)

- Allows you to breath and chew at the same time 
- Uvula closes off nasal passages during swallowing

Teeth: tearing, grinding, mixing food

- Upper and lower teeth fit together (occlusion) 
- Occulision grinds food
- Break it down to something that can be acted upon by enzymes 
- Exposure of taste buts is important 

Chewing: initially voluntary then reflexive.
- Reflexive contraction of jaw, lip, cheek, tongue muscles mediated by sensory afferents. Make sure it’s doing its job.
- Taste buds initate long loop reflective
Salivary, gastric, pancreatic, bile in anticipation.

Question 2

Describe secretions of the oral cavity.

Answer 2

Secretion: salivary glands.

- Parotid, submandibular, sublingual. 
- All coordinate release of contents through duct (exocrine glands) into a duct. 
- Saliva is product. 

Mostly water, some electrolytes and protien

- Needed for dissolving 
- Amalase and lysozyme and musus

- Stimulate taste buds 
- Aids in speech (when mouth is dry in sympathetic drive, its hard to speak) 
- Clean out mouth and flush food residue away 

Mucus; slippery glycoproteins.

- Makes bolus 
- Lubricates it so it doesn't get stuck. 

Salivary secretions: saliva and mucus.

Amalase: breaks down polysacc to maltose.

- Initation for carb digestion. 
- **where does digestion occur for various nutrients** know this for the test. 

- Not hugely important, and have no issue digesting carbs. 

Lysozyme: lyses the cell wall of some bacteria

- Protection against infection. 
- Sometimes you'll inject bacteria with every bite, so you have lysozyme to decrease the bacteria there. 

Bicarbonate ion: neutralizes acid foods.

- Makes it not too acidic to help with dental health
- Acid makes cavities.