B5.005 - GI Physiology 1

Question 1

parotid gland

Answer 1

salivary gland 20% of saliva largest, serous, releases saliva on the inside of the cheek across from the second upper molars

Question 2

submandibular gland

Answer 2

70% of saliva mucous and serous, releases saliva through the floor of the mouth behind the bottom front teeth

Question 3

sublingual gland

Answer 3

5% of saliva mucous and serous, release fluid from under the tongue

Question 4

stimuli for salivary gland

Answer 4

cephalic activity, chewing, nausea inhibited during sleep. fear, fatigue

Question 5

major control of salivary secretions

Answer 5

parasympathetic

Question 6

what causes vasodilation in salivary glands

Answer 6

VIP ACh

Question 7

acinar serous cells in salivary glands are stimulated by what

Answer 7

ACh, NE, substance P, VIP

Question 8

duct cells in salivary glands are stimulated by

Answer 8

ACh and NE

Question 9

describe saliva relative to plasma

Answer 9

hypotonic relative to plasma, help with tasting of foods, diluting of substances like keeping glucose concentration down

Question 10

what are mucins

Answer 10

lubricate and modulate adhesions of microorganisms

Question 11

what do amylases do

Answer 11

break down starch to oligosaccharides

Question 12

what do proline rich proteins do

Answer 12

they are antimicrobials

Question 13

what does bicarb do

Answer 13

protects erosion of teeth, neutralizes gastric secretions that reflux into the esophagus

Question 14

how many muscles and nerves are involved in swallowing

Answer 14

50 muscles and 6 cranial nerves for sensory and motor functions

Question 15

describe the initiation of swallowing

Answer 15

initiation is under voluntary control while the ensuing sequence of events occur as a pattern elicited response (under involuntary control) which is not a true reflex

Question 16

how is the swallow divided

Answer 16

oral pharyngeal esophageal phases

Question 17

oral stage of swallowing

Answer 17

mastication/chewing breaks cell wall of plan tmaterial to expose contents the tongue and cheeks facilitate chewing by moving the food between the teeth food is mixed with saliva and formed into a bolus of the correct size and consistency for swallowing

Question 18

what does the tongue do in the oral stage of swallowing

Answer 18

facilitates formation, containment and propulsion of bolus

Question 19

describe the propulsion of food

Answer 19

tip of tongue pressed against the palate lateral regions form seals with alveolar ridges and pharyngeal walls tongue moves in a wave motion along central groove pushing the bolus back towards pharynx anterior 2/3 of tongue and negative pressure in pharyngoesophageal segment are primarily responsible for the driving force propelling the bolus towards the pharynx which results in the temporary suppression of respiration

Question 20

bolus transit is impaired in what scenarios

Answer 20

following a tongue injury or lanryngectomy

Question 21

describe neural control of swallowing

Answer 21

signals are transmitted along afferent nerves to the swallowing center in the brainstem the pattern of incoming signals is identified and produces an appropriate set of signals to other neurons that in turn coordinate the muscles involved with swallowing, opening of the upper esophagus sphincter, cessation of breathing and peristalsis in the esophagus

Question 22

what is the cricopharyngeus muscle

Answer 22

a horizontal striated sphincter muscle located a the top of the esophagus makes up the UES together with non-muscular components

Question 23

what does the cricopharyngeus muscle do

Answer 23

controls the flow of material between the pharynx and esphagus tonically contracted at rest and relaxes during swallowing, vomiting and belching

Question 24

describe relaxation of cricopharyngeus

Answer 24

not direct inhibitory signals acting on the muscle, rather inhibition of firing that causes tonic contraction

Question 25

mechanisms involved in preventing aspiration

Answer 25

prevention of premature spill rapid and coordinated movement of the bolus through the oral cavity and pharynx laryngeal elevation to move out of the way, laryngeal closure, epiglottis inversion bolus that does enter trachea triggers a strong cough

Question 26

what is dysphagia

Answer 26

difficulty/pain/discomfort in swallowing

Question 27

consequences of dysphagia

Answer 27

asphyxiation, aspiration pneumonia, dehydration, starvation, weight loss

Question 28

who commonly gets dysphagia

Answer 28

elderly

Question 29

symptoms in disorders of oropharyngeal dysmotility

Answer 29

drooling gagging trouble swallowing wet voice hoarseness slow eating coughing choking sore through weight loss dyspnea fever, sweats

Question 30

describe the functional changes in the oral phase with oropharyngeal dysmotility

Answer 30

abnormal bolus control impaired swallow initiation abnormal bolus transport

Question 31

describe the functional changes in the pharyngeal phase with oropharyngeal dysmotility

Answer 31

muscle weakness or incoordination pharyngeal outflow obstruction

Question 32

functional deficites of oropharyngeal dysmotility can be categorized by what

Answer 32

phase of swallowing affected 1. difficulty initiating swallow 2. nasopharyngeal regurgitation 3. pulmonary aspiration 4. residual in vallecula (space between post aspect of tongue and epiglottis)

Question 33

describe how aspiration occurs

Answer 33

during the swallow there is poor opening of the UES and substantial retention of bolus within the hypopharynx. During a subsequent dry swallow some of this material enters the airway

Question 34

failure of UES relaxation may be caused by what

Answer 34

neuro disorders like parkinsons amyotrophic lateral sclerosis

Question 35

impaired opening of UES may be caused by what

Answer 35

cricopharyngeal fibrosis, suboptimal pharyngeal propulsion, neural problem zenkers diverticulum

Question 36

what is zenkers diverticulum

Answer 36

a structural disorder due to fibrosis of cricopharyngeus muscle resulting in increased intrabolus pressure during swallow

Question 37

hypopharyngeal intrabolus pressure is an indirect measure of what

Answer 37

UES compliance

Question 38

what is intrabolus pressure

Answer 38

the obstruction (resistance) to flow across the pharyngo-esophageal junction during swallowing

Question 39

what is nadir UES

Answer 39

the lowest pressure during relaxation; higher than normal can indicate diminished UES relaxation or diminished opening of UES

Question 40

Answer 40

zenkers diverticulum herniation between inferior pharyngeal constrictor and cricopharyngeus

Question 41

presentation of zenkers diverticulum

Answer 41

disphagia aspiration regurgitation halitosis noisy deglutition changes in voice

Question 42

Answer 42

normal cricopharyngeus muscle

Question 43

Answer 43

muscle dropout due to necrosis, variability in fiber size, increase in fibroadepose tissu zenkers diverticulum results in restricted opening of UES

Question 44

Answer 44

cricopharyngeal bar associated with failure of teh cricopharyngeus to relax when suprahyoid muscles contract the lumen of the open UES is obstructed by the contracted circopharyngeus that appears as a bar

Question 45

what types of muscle make up the esophagus

Answer 45

striated and smooth

Question 46

describe the layers of the esophageal muscle from superficial to deep

Answer 46

longitudinal muscle circular muscle esophagel glands submucosa muscularis mucosae tunica propria stratified squamus epithelium lumen

Question 47

how long does a swallow last

Answer 47

8-10 s

Question 48

what is primary peristalsis

Answer 48

continued peristaltic wave from that started in pharynx aka stripping wave

Question 49

what is secondary peristalsis

Answer 49

if residual food in esophagus, initiated by intrsinsic nervous system and vago-vagal responses. Can have the same strenght and speed as primary peristalsis and is generated in absesce of a swallow

Question 50

in striated esophagus peristalsis is under what control

Answer 50

central control

Question 51

in the smooth muscle peristalsis is under what control

Answer 51

intrinsic

Question 52

describe the biochemical signaling happening to produce a swallow

Answer 52

upon swallowing the inhibitory pathway nuerons in the cuadal DMN are activated first, which acuses simultaneous inhibition of all parts of the esophagus. This inhibition lasts longer in the lower parts than the upper parts. As the inhibition ends, sequential activation of excitatory (cholinergic) neruons in the rostarl DMN elicits a contraction wave that is peristaltic in nature.

Question 53

describe the excitatory pathway in a swallow

Answer 53

includes vagal preganglionic neruons that are locatd in the rostral part of ht eDMN in the brainstem. Thes fiber project inot the excitatory postganglionic neruons that conatin ACh and substance P.

Question 54

describe the inhibitory pathway in a swallow

Answer 54

includes preganglionic vagal fibers that are located in the caudal part of teh DMN. The fibers project onto the postganglionic inhibitory neurons that contain NO, VIP and ATP and substance P.

Question 55

what happens when swallows are performed in rapid succession

Answer 55

the pharynx and UES respond on a one to one basis and the LES remains relaxed. peristalsis in the esophagus is inhibited until after the last swallow.

Question 56

localized esophageal motor disorders

Answer 56

1. achalasia like syndromes 2. diffues esophageal spansm 3. nutcracker esophagus 4. hypertensive LES

Question 57

diffuse esophageal motor disorders

Answer 57

GERD scleroderma myopathies diabetes parkinsons idiopathic pseudo obstruction

Question 58

hypotensive peristalsis

Answer 58

contractions have a decreased strength leading to impaired esophageal transit also can have impaired clearance of refluxed contents main symptom is dysphagia although reflux symptoms may be present or predominate

Question 59

what labs would demonstrate hypotensive peristaltic contractions

Answer 59

espac eof barium bolus in proximal esophagus due to a weak peristaltic contractionw ave. shows a simultatnesou monometry nd fluoroscopy of a barium swallow

Question 60

Answer 60

scleroderma esophagus

Question 61

what is scleroderman esophagus

Answer 61

thought to have autoimmune origin chronic disorder characterized by diffuse fibrosis of skin and internal organs. Damae to smallblood vessesl are often among earliest signs

Question 62

what is raynauds phenomenon

Answer 62

reducton of blood flow in response to cold or stress resultin gin idscoloration; white can turn to blue followed by flushing resulting in red appearance

Question 63

what is telangiectasia

Answer 63

dilated blood vessels near the surface of the skin

Question 64

what is hypertensive peristalsis

Answer 64

nutcracker esophagus normal sequence of peristalsis on barium swallow, normal appearance on esophagoscophy, but smooth muslce contractions have excessive amplitude or duration as detected by manometry symptoms include chest pain, dysphagia

Question 65

what is diffuse esophageal spasm

Answer 65

inhibitory nerves are disrupted leadin to simultaneous contraction in the smooth muslce of esophagus. contractions occur following swallowing or spontaneously. Deglutitive inhibition is also impaired.

Question 66

symptoms of diffuse esophageal spasm

Answer 66

chest pain, dysphagia, possible regurgitation

Question 67

what does a barium swallow of diffuse esophageal spasm look like

Answer 67

simultaneous contractions that appear corkscres, multiple ripples or sacculations

Question 68

what part of the esophagus is affected by esophageal spasm

Answer 68

the lower part (smooth muscle)

Question 69

what is deglutitive inhibition

Answer 69

A wave of inhibition precedes a swallow-induced peristaltic contraction in the smooth muscle part of the human oesophagus involving both circular and longitudinal muscles in a peristaltic fashion. Deglutitive inhibition is necessary for drinking liquids which requires multiple rapid swallows