Case 1 - PBL

Question 1

what is included in the voluntary phase of swallowing

Answer 1

mastication: leads to a bolus of food being produced, during this stage the back of the tongue is elevated and the soft palate pulled anteriorly against it. this keeps the food within the oral cavity and allows the airway to remain open

Question 2

what happens after mastication in the voluntary phase

Answer 2

inspiration is inhibited and the bolus of food is moved to the pharynx by the tongue. this leads to the stimulation of the swallowing reflex

Question 3

what is the nerve involved in the voluntary phase

Answer 3

the trigeminal nerve

Question 4

what happens in the pharyngeal phase

Answer 4

Once the bolus has been moved to the pharynx, pressure receptors are activated in the palate and the anterior pharynx. This signals the swallowing centre in the brain stem which:

inhibits respiration
Raises the larynx
Closes the glottis
Opens the upper oesophageal sphincter
Levator and tensor veli palatini

Question 5

what else happens to prevent aspiration

Answer 5

the true vocal cords are closed

Question 6

what happens after the vocal cords are closed and the soft palate is elevated

Answer 6

the bolus is moved towards the oesophagus via peristalsis of the pharyngeal constrictor muscles. Gravity makes very little contribution to this process and the main factors affecting the speed of this are the viscosity and volume of the bolus.

Question 7

what is the upper third of the oesophagus

Answer 7

voluntary skeletal muscle

Question 8

what are the lower two thirds of the oesophagus

Answer 8

involuntary smooth muscle

Question 9

what muscle prevents reflux

Answer 9

the larynx lowers, returning to its normal position. the cricopharyngeus muscle then contracts to prevent reflux and respiration begins again

Question 10

what happens after this

Answer 10

The bolus is moved down the oesophagus via peristalsis, which is coordinated by extrinsic nerves. Each area of muscle systematically relaxes to allow food through and contracts afterwards to propel it further. The bolus is propelled at a rate of around 3-5cm per second and so the transit time to the stomach takes around 9 seconds.

Question 11

digram showing swallowing

Answer 11

Question 12

what are long periods of low flow of saliva broken by

Answer 12

short periods of high flow, which is stimulated by taste and mastication

Question 13

what is the nerve mediated salivary reflex modulated by

Answer 13

nerve signals from other centres in the central nervous system, which is most obvious as hyposalivation at times of anxiety

Question 14

what does circadian rhythm affect

Answer 14

salivary flow and ionic composition

Question 15

what evokes salivary secretion

Answer 15

Cholinergic parasympathetic and adrenergic sympathetic autonomic nerves evoke salivary secretion, signalling through muscarinic M3 and adrenoceptors on salivary acinar cells and leading to secretion of fluid and salivary proteins.

Question 16

what do the main proteins present in saliva do

Answer 16

create viscoelasticity and enabling the coating of oral surfaces with saliva

Question 17

examples of potential disease biomarkers found in saliva

Answer 17

For example, cortisol levels are used in the assessment of stress, matrix metalloproteinases-8 and -9 appear to be promising markers of caries and periodontal disease, and a panel of mRNA and proteins has been proposed as a marker of oral squamous cell carcinoma. Understanding the mechanisms by which components enter saliva is an important aspect of validating their use as biomarkers of health and disease.

Question 18

what are the parasympathetic nuclei that control salivary glands in the brainstem

Answer 18

the superior and inferior salivatory nucleu

Question 19

parasympathetic stimulation

Answer 19

an increase in the secretion of watery saliva, is mediation by CN7&9 from the superior and inferior salivatory nuclei in the brains stem via muscarinic receptors
Parasympathetic nerve stimulation occurs via the IP3 intracellular pathway, whereby calcium released in this pathway activates the relevant channels and transport proteins to cause this increase in secretion

Question 20

sympathetic stimulation

Answer 20

mediated by Beta-adrenergic receptors and causes an increase in secretion of viscous saliva
Sympathetic stimulation increases salivation a slight amount, much less so than parasympathetic stimulation
salivation also occurs in response to reflexes originating in the stomach and upper small intestines - particularly when irritating foods are swallowed
The saliva when swallowed, helps to remove the irritating factor in the gastrointestinal tract by dilating or neutralising the irritant substance.

Question 21

why does blood supply affect saliva production

Answer 21

because secretion always requires adequate nutrients from the blood

Question 22

does salivation dilate blood vessels

Answer 22

yes, thus providing increased salivary gland nutrition as needed by the secreting cells

Question 23

what is part of this additional vasodilator effect caused by

Answer 23

kallikrein secreted by the activated salivary cells, which in turn acts as an enzyme to split one of the blood proteins to form bradykinin, a strong vasodilator

Question 24

what is the serum ferritin test and what are normal results

Answer 24

measures the amount of ferritin in your blood
Is a blood protein that contains iron
A ferritin test helps your doctor understand how much iron your body stores
Ferritin stores iron

Normal results:
Woman: 11-307 micrograms per litre
Men: 24-336 micrograms per litre

Question 25

what is ESR and what are the normal results

Answer 25

blood test that can reveal inflammatory activity in your body When your blood is placed in a tall, thin tube, red blood cells gradually settle to the bottom. Inflammation can cause the cells to climb Because these clumps are denser than individual cells, they settle at the bottom more quickly. The sed rate measures the distance red blood cells fall in a test tube in one hour The farther the red blood cells have descended, the greater the inflammatory response of your immune system. The normal values are: 0 to 15 mm/hr in men. 0 to 20 mm/hr in women.

Question 26

what is the upper GI criteria for a HSC205 referral

Answer 26

people with dysphagia, or those aged 55 years and over with weight loss and any of the following: - upper abdominal pain - reflux - dyspepsia

Question 27

PEG tube benefits and facts

Answer 27

avoids mouth/nose issues More invasive Requires endoscopy Better tolerated displacement less likely Endoscopic procedure Percutaneous wound Larger bore tube long term Continuous/bolud Fluid More expensive Can aspirate Avoids interfering with gastro-oesophageal sphincter

Question 28

NG tube positives and facts

Answer 28

simple Commonly used No need for anaesthesia trauma Misplacement Requires X-ray Easily dislodged Sinusitis short term Continuous/bolus Fluid cheap Can aspirate Buffers gastric acids Bactericidal action of acid Pepsin and lipase help with absorption

Question 29

what is oesophageal stenting

Answer 29

a tube is placed in your oesophagus to keep open a blocked area The tube helps you swallow solids and liquids Used when you have dysphagia Can take place under general anaesthesia or conscious sedation If it takes place under GA you will sleep through the procedure and feel no pain If it takes place under conscious sedation, you will get medications to make you relaxed and sleepy

Question 30

mechanism of action of omeprazole

Answer 30

is a proton pump inhibitor It is a substituted benzimidazole that belongs to the antisecretory class of compounds It inhibits the parietal cells H+/K+ ATP pump, the final step of acid production In turn, omeprazole surpasses gastric basal and stimulates acid secretion The inhibitory effects occur rapidly, within 1 hour of administration. Lasts 72 hours after administration extensively metabolised by the hepatic cytochrome P450 enzyme system

Question 31

self regulation model of illness cognition

Answer 31

Question 32

unidimensional measures of QoL

Answer 32

these measures assess health in terms of one specific aspect of health They can be used on their own or in conjunction with other measures Examples: General heath questionnaire - assesses mood McGill Pain Questionnaire - assesses pain levels Self esteem scale Measures of social support Measures of satisfaction with life Measures of symptoms

Question 33

multidimensional measures of quality of life

Answer 33

these measures assess health in the broadest sense Aren’t always long and complicated Doctors can simply ask respondents to make a relative judgement about their health on a scale from best to worst possible

Question 34

individual measures of quality of life

Answer 34

measures of subjective health status ask the individual to rate their own health This is in contract to measures of mortality, morbidity and most measures of functioning which are completely by carers, researchers or an observer Although these measures enable individuals to rate their own health, they do not allow them to select the dimensions along which to rate it. For example, a measure that asks about an individual’s work life assumes that work is important to this person, but they might not want to work

Question 35

what is pneumonitis

Answer 35

inflammation of the lung tissue