Mouth, Salivary Glands, Esophagus Flashcards
functions of chewing
- 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)
how long should you chew soft foods v. hard foods
soft: 5-10x hard: 30x
saliva is a mixture of secretions from which glands and percentages from each
- parotid (amylase - 25%)
- sublingual (5%)
- submandibular (mucous and serous glands - 70%)
what is amount of saliva we produce each day and its pH
1-2L/day with a pH of 7-8
salivation is increased by
sight and smell of food
saliva is a mixture of what secretions and what are each made up of
- serous cell secretion - low glycoprotein, high amylase
- mucous cell secretion - high mucin glycoprotein
enzymes in saliva
amylase and lipase
electrolytes in saliva
Na+, K+, Cl-, Ca2+, HCO3-, PO4-
other components of saliva
- mucus
- lysozyme (attack bacteria cell wall)
- lactoferrin (chelates iron needed by bacteria for replication
- IgA (kills bacteria)
- epidermal factor growth (stimulates gastric mucosal growth)
condition of dry mouth
xerostomia
functions of saliva
lubricate, digest, and protect
how does saliva lubricate, digest, and protect
- lubricate: moistens mouth, swallowing, speech, taste
- digest: amylase – starch(75%) pH - alk, lipase-fat, ph-acid
- protection: adverse effects of oral bacteria (lysozyme)
Describe the salivion schematic
- acinar cells secrete electrolytes
- myoepithelial cells - contract and propel saliva
- ductal cells - facilitate reabsorption and secretion
in mouth, site of secretion
acinus and duct
of the two secretion cells, which is leaky and which is tight
acinus is leaky and ducts are tight
primary secreted ion in the acinar cells
Cl- (main one), K+, and HCO3-
how does secretion work in the acinar cells
- 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)
Describe how secretion works in the duct
- 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
characteristics of ductal cells
- 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+
how does salivary flow rate affect concentration of saliva
- 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
why does bicarb increase with increasing salivary rate
it is selectively stimulated when saliva secretion is stimulated
what stimulates the salivary nucleus of the medulla oblangata
conditioned reflexes, smell, taste, tactile stimuli, nausea
what decreases the stimulation of the salivary nucleus
sleep, fear, fatigue, dehydration, drugs like antihistamines
what ANS controls salivary secretion
both parasympathetic and sympathetic but mainly parasympathetic
what does activating the salivary gland cause
secretion, vasodilation, myoepithelial contraction
difference in resting state salivary secretion and stimulated gland secretion
resting: 30ml/hr
stimulated: 400ml/hr
difference in agonists that release calcium (parasymp) and agonists that increase cAMP (symp)
- agonists that release calcium: greater effect on volume of secretion
- agonist that elevate cAMP - increase enyzmes and mucous content
explain the pic
self explanatory
difference between the upper and lower part of the esophagus
- 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
describe the voluntary component of swallowing (deglutition)
- 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
define the involuntary component of swallowing
- pharyngeal phase (2 sec) and esophageal phase (8-10 sec)
- stim of epithelial swallowing center in pharynx
- swallowing reflex
- peristalic waves
origin of the primary vs. secondary peristaltic wave
- 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
what is UES
thickening of the striated muscle
what is LES
- terminal 1-2cm of the esophagus
- define more functionally than anatomically
- smooth muscle
what does UES and LES have to do to allow food to enter
they have to relax
needed for motility
ENS and the vagus
needed for contraction and relaxation
contraction - acetylcholine
relaxation - nitric oxide
difficulty initiating swallowing with coughing and choking
oropharyngeal dysphagia
causes of oropharyngeal dysphagia
anatomic, neurologic, motor, or UES abnormalities
food stopping or sticking on swallowing
esophageal dysphagia
esophageal dysphagia - solid foods are worse than liquids is what type of problem
mechanical obstruction
esophageal disorder - solids and liquids are both of equal problem is what type of problem
motility disorder
causes of mechanical obstruction in esophageal dysphagia
peptic stricture, lower esophageal ring, oesphageal cancer, GERD
causes of motility disorder in esophageal dysphagia
esophageal spasm, scleroderma, achalasia (initially)
A 17 years old female ingests malathion. what ionic change to the composition of her saliva would you see?
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
