Physiology of Swallowing and Dysphagia Flashcards
Mastication including reflexes
Important beginning of digestion for carbs
incisors for tearing and molars to crush
Voluntary and involutnary
Tonic tone in masseter
Reflexie - muscles are innervated by trigeminal nerve and can be inittiatied by hypothalamus or cortec
Chewing reflex - bolus of food against lining of the mouth causes reflexive relaxation of striated jaw muscles…jaw drops…monosynoatic stretch reflex causes rebound contraction
Masseter relaxes-=–jaw drops—musucle stretched—-muscle spindles act—-initiates reflex contraction—-inc tension activates golgi tendon organs—reflex relaxation
Strenght of chewing
Role of periodontal ligament
If false teeth, cannot exert as much force
Deglutition
Can be initiated voluntarily but after oral phase, becomes reflexive
NTS - needs CNS innervation
Includes a reflex component to inhibit inspiration and prevent aspiration
Phases of deglutition
Buccal - tactile receptors in mouth and pharynx - affarnet (5,7,9,10) and efferent (5,7,9,10,12)
Pharyngeal - soft palate moved up and palatopharyngeal folds close…epiglottis covers trachea…UES relaxes (as well as LES)…peristaltic wave begins in superior contstrictor
Esophageal - strong peristaltic wave ocnducted donw
Peristalsis
Moving ring contractions controlled both extrinscially and intrinsically
Upper requires CNS control
Mainly as a conduit
Wave like contraction
Circular smooht muscle contracts behind and relaxes in front of
Followed by longitudinal contraction
After food to stomach, LES constricts
Primary and seoncdary peristalsis
Pirmary - controlled by BS…need vagal efferent
LES is relaxed at beginnign and stays open til end due to BS control and vagal activity (VIP/NO)
When drinking, occurs only after the last swallow
Cold water eliminates peristalsis but LES relaxes
If food cannot move through, initiates less eff secondary peristalsis
General features of esophagus
Negative pressure throught but stomach pressure pos
LES maintains greater pressure than stomach
Ach and gastrin inc constriction of LES
Dysphagias
LES cannot close completely and esophageal lining is damaged
Pregnancy - progesterone and inc abdomina tone
Peristaltic cirucity incomplete in infatns
Heartburb-GERD-esophagitis
Bruning sensation
Pressure in stmoach Eff of LES Clearance of esopahgis\ Aciditiy of regurged contents Repair of esophagus
Achalasia
LES does not relax properly so food accumulates above the LES
Results in secondary peristalsis
Usually due to myhenteric pleus probs
Painless and progressive dysphagia
Diffuse esophageal spasm
Abnormal sequencing of peristalsis prevents food from moving
Simulataneous long contraction of lower esoph…can be triggered by hot or cold fluids
