Mouth, Salivary Glands, Esophagus

Question 1

functions of chewing

Answer 1

• reduces particle size of food (aids in swallowing and increases surface area for enzymes)
• moves food in the oral cavity (stimulates taste smell receptors, promotes saliva secretion, CHO digestion starts)

Question 2

how long should you chew soft foods v. hard foods

Answer 2

soft: 5-10x hard: 30x

Question 3

saliva is a mixture of secretions from which glands and percentages from each

Answer 3

• parotid (amylase - 25%)
• sublingual (5%)
• submandibular (mucous and serous glands - 70%)

Question 4

what is amount of saliva we produce each day and its pH

Answer 4

1-2L/day with a pH of 7-8

Question 5

salivation is increased by

Answer 5

sight and smell of food

Question 6

saliva is a mixture of what secretions and what are each made up of

Answer 6

• serous cell secretion - low glycoprotein, high amylase
• mucous cell secretion - high mucin glycoprotein

Question 7

enzymes in saliva

Answer 7

amylase and lipase

Question 8

electrolytes in saliva

Answer 8

Na+, K+, Cl-, Ca2+, HCO3-, PO4-

Question 9

other components of saliva

Answer 9

• mucus
• lysozyme (attack bacteria cell wall)
• lactoferrin (chelates iron needed by bacteria for replication
• IgA (kills bacteria)
• epidermal factor growth (stimulates gastric mucosal growth)

Question 10

condition of dry mouth

Answer 10

xerostomia

Question 11

functions of saliva

Answer 11

lubricate, digest, and protect

Question 12

how does saliva lubricate, digest, and protect

Answer 12

• lubricate: moistens mouth, swallowing, speech, taste
• digest: amylase – starch(75%) pH - alk, lipase-fat, ph-acid
• protection: adverse effects of oral bacteria (lysozyme)

Question 13

Describe the salivion schematic

Answer 13

1. acinar cells secrete electrolytes
2. myoepithelial cells - contract and propel saliva
3. ductal cells - facilitate reabsorption and secretion

Question 14

in mouth, site of secretion

Answer 14

acinus and duct

Question 15

of the two secretion cells, which is leaky and which is tight

Answer 15

acinus is leaky and ducts are tight

Question 16

primary secreted ion in the acinar cells

Answer 16

Cl- (main one), K+, and HCO3-

Question 17

how does secretion work in the acinar cells

Answer 17

• Cl is co transported with Na into the cell at the BLm
• Electrochemical potential of Cl changes
• Cl diffuses down the gradient
• Channel allows HCO3 to enter
• Na and H2O followparacellularly
• because it is leaky and permeable to water, it is isotonic (H20 follows NaCl)

Question 18

Describe how secretion works in the duct

Answer 18

• active reabsorption of Na (main ion here)
• Na/K ATPase pump on BL membrane determines ..extra K brought into the cell is actively secreted
• anionic exchange: Cl is reabsorbed and HCO3- is secreted

Question 19

characteristics of ductal cells

Answer 19

• reabsorb NaCl while secreting KHCO3
• tight so not permeable to water hence water can’t follow the NaCl
• hence making saliva hypotonic, alkaline (HCO3-), and high K+

Question 20

how does salivary flow rate affect concentration of saliva

Answer 20

• if slow salivary flow rate, then there is increased contact time
• with increased contact time, there is more NaCl reabsorption and K+ secretion
• makes saliva less concentrated so lower Na, Cl, and HCO3
• but highest K concentration
• so increase the flow then you increase the tonicity

Question 21

why does bicarb increase with increasing salivary rate

Answer 21

it is selectively stimulated when saliva secretion is stimulated

Question 22

what stimulates the salivary nucleus of the medulla oblangata

Answer 22

conditioned reflexes, smell, taste, tactile stimuli, nausea

Question 23

what decreases the stimulation of the salivary nucleus

Answer 23

sleep, fear, fatigue, dehydration, drugs like antihistamines

Question 24

what ANS controls salivary secretion

Answer 24

both parasympathetic and sympathetic but mainly parasympathetic

Question 25

what does activating the salivary gland cause

Answer 25

secretion, vasodilation, myoepithelial contraction

Question 26

difference in resting state salivary secretion and stimulated gland secretion

Answer 26

resting: 30ml/hr stimulated: 400ml/hr

Question 27

difference in agonists that release calcium (parasymp) and agonists that increase cAMP (symp)

Answer 27

- agonists that release calcium: greater effect on volume of secretion - agonist that elevate cAMP - increase enyzmes and mucous content

Question 28

explain the pic

Answer 28

self explanatory

Question 29

difference between the upper and lower part of the esophagus

Answer 29

- upper part of the esophagus is UES (upper esophageal sphincter) and is made up of striated muscle and is voluntary - lower part of the esophagus is LES (lower esophageal sphincter) and is made up of smooth muscle and is involuntary

Question 30

describe the voluntary component of swallowing (deglutition)

Answer 30

- there is the oral phase - food is shaped into a bolus then collected on the tongue and pushed into pharynx - tongue is raised onto the hard palate creating a pressure gradient that forces the food into the pharynx

Question 31

define the involuntary component of swallowing

Answer 31

- pharyngeal phase (2 sec) and esophageal phase (8-10 sec) - stim of epithelial swallowing center in pharynx - swallowing reflex - peristalic waves

Question 32

origin of the primary vs. secondary peristaltic wave

Answer 32

- primary: arises from the act of swallowing in absence or presence of food and is voluntary - secondary: occurs from distension of the esophagus and is involuntary and has low pH

Question 33

what is UES

Answer 33

thickening of the striated muscle

Question 34

what is LES

Answer 34

- terminal 1-2cm of the esophagus - define more functionally than anatomically - smooth muscle

Question 35

what does UES and LES have to do to allow food to enter

Answer 35

they have to relax

Question 36

needed for motility

Answer 36

ENS and the vagus

Question 37

needed for contraction and relaxation

Answer 37

contraction - acetylcholine relaxation - nitric oxide

Question 38

difficulty initiating swallowing with coughing and choking

Answer 38

oropharyngeal dysphagia

Question 39

causes of oropharyngeal dysphagia

Answer 39

anatomic, neurologic, motor, or UES abnormalities

Question 40

food stopping or sticking on swallowing

Answer 40

esophageal dysphagia

Question 41

esophageal dysphagia - solid foods are worse than liquids is what type of problem

Answer 41

mechanical obstruction

Question 42

esophageal disorder - solids and liquids are both of equal problem is what type of problem

Answer 42

motility disorder

Question 43

causes of mechanical obstruction in esophageal dysphagia

Answer 43

peptic stricture, lower esophageal ring, oesphageal cancer, GERD

Question 44

causes of motility disorder in esophageal dysphagia

Answer 44

esophageal spasm, scleroderma, achalasia (initially)

Question 45

A 17 years old female ingests malathion. what ionic change to the composition of her saliva would you see?

Answer 45

malathion is an anticholinesterase which will increase acetylcholine in cleft hence increasing parasympathetic activity which would increase salivation rate -- increase in salivary rate leads to increased sodium conc, increased HCO3, increased chloride, increased osmolarity, decreased K decreased contact time so sodium reabsorption decreases