What are the three stages of swallowing? Which are automatic?
1) Voluntary (initiation)
2) Pharyngeal
3) Oesophaygeal
2+3 are automatic
When epithelial swallowing receptor area’s are stimulated which nerves carry the information and to which centres?
CN V and CN IX
To nucleus of solitary tract and reticular substance neuronal area in pons/ medulla
Which muscles comprises the UES (upper oesophageal sphincter)?
Cricopharyngeus
What are tertiary contraction waves?
Not peristaltic, caused be events such as fluroscopy
ACh and Substance P are examples of what type of NT when acting in the nerves of the GI system?
Excitatory
VIP and nitric Oxide are examples of what type of NT when acting in the nerves of the GI system?
Inhibitory
What percentage of patients who suffer stroke experience dysphagia?
40%
What is the definition of dysphagia?
Abnormal food transfer from mouth to stomach
What is the difference between aspiration and penetration in relation to dysphagia?
Aspiration- Food decends below vocal cords
Penetration- Food enters larynx but stays above vocal cords
What proportion of stroke patients aspirate on swallow and what percentage go on to develop aspiration pneumonia?
1/3 aspirate on swallow
1/9 go on to develop AP
What are the general symptoms of dysphagia?
Difficulty or inability to swallow
Coughing/ choking when eat/drink
Persistant saliva drooling
Changes in voice/ resp status/ temp
Name two long term symptoms of patients with dysphagia?
Weight loss
Recurrent chest infections
What diagnostic tests could be used to observe for dysphagia?
Water swallow (quick 150ml swallow) Videofluroscopy (modified barium swallow)- X-ray P whilst drinking (barium is non-toxic) FEES (Fiberoptic endoscopic examination of swallow)- Camera inserted into nose and swallow observed
What are the pro’s/cons of PEG vs NGT?
NGT- Swap nostrils each month (irritation/ infection risk)
PEG- Tube into stomach (infection/ hemorrhage/ displacement/ more difficult to resume normal feed)
What is the treatment for oropharyngeal (high) dysphagia?
SLT swallowing therapy (exercises)
Diet changes (Softer foods/ thicker fluids)
Feeding tubes (NGT/PEG)
Head postural adjeustments - SLT
What is a PEG tube?
Percutaneous endoscopic gastrostomy
Flexible feeding tube through abdomen into stomach/ intestine
What is the treatment options for oesophageal (low) dysphagia?
PPI’s to lower acid production
Botox (paralyse oesophageal muscles)
Surgery (stent/ ballon)
What is the most common site of aspiration pneumonia?
Lower lobe of R lung
How is aspiration pneumonia best prevented?
Bed bound patients with dysphagia best kept at >30degrees
Give NGT for at risk patients
What is the compostition of saliva? How much is secreted each day?
1L secreted each day
- 4% water
- 6% (Na/Cl/HCO3/ Glycoproteins/enzymes)
What gives salvia it’s lubricating action?
Glycoproteins called mucins
What antibiotic is present in saliva?
Lysozyme
What enzymes are present in saliva?
Salivary amylase (starch to sugar)
How does the pH/ osmolarity of saliva change if it is secreted at a low rate or a high rate?
Low rate: pH 6-7 (slightly acidic) + hypotonic
High rate: Closer to isotonic (More Na/ less K+ and HCO3-)
What are the three main salivary glands and what do each secrete?
Submandibular (70%)- Mucous + serous
Sublingual (5%)- Mucous (high in glycoprotein- sticky)
Parotid (25%)- Serous (Watery- protein/enzymes/ ptyalin)
What is ptyalin?
A major form of amylase
By what intracellular pathways does PNS stimulation affect saliva production?
ACh binds to muscarinic receptors + Substance P binds to tachykinin NK-1 receptors
This increases saliva secretion by activating signalling pathways:
IP3 calcium 2qnd messenger / DAG 2nd messenger
By what intracellular pathways does SNS stimulation affect saliva production?
SNS from T1-T3 sup cervical ganglion uses NA to activate Badrenergic receptors, increasing cAMP
What determins the permiability of the tight junctions between the cells of the salivary duct acini?
Claudin proteins (these are the most important components of TJ's)
Which is the most important H2O channel in salivary ducts?
Aquaporin 5
What type of flow happens through ion channels?
Passive, driven by conc gradient
What type of flow happens through aquaporins?
Passive, driven by osmosis
What type of flow happens through carriers?
Either facilitated diffusion (not ATP) or active transport (uses ATP)
What type of flow happens through uniporters?
Facilitated diffusion (Passive, down conc grad0 Undergo's conformational change E.g GLUT1 or GLUT2 transporters
What type of flow happens through symporters?
Secondary active transport (ATP used)
One substance brought in against gradient
Electrochemical gradient from other substance used for energy purposes
What type of flow happens through anti-porters?
Secondary active transport (ATP used)
One substance brought in against gradient
Electrochemical gradient from other substance used for energy purposes
What type of flow happens through pump channels?
Primary active transport
ATP binds to pump and it undergoes conformational change
What are the actions of the TMJ?
Translation and rotation
What is the most likely location for food or a fishbone to become wedged in the throat?
Piriform fossa
between aryepiglottic fold and thyrohyoid membrane
What is the foreamen cecum?
Embryological remnant of thyroglossal duct
Tumour/ lump distinguishable as it’s the only one that moves when tongue protruded
What is the first muscle to contract in the swallowing sequence?
Myelohyoid
Which two neurotransmitters regulate peristalsis and how?
ACh and nitric oxide (smooth muscle relaxants)
How long does an average swallow take? How many times do we swallow per day?
0.5-1sec
1000x per day
When testing a patients swallows how many should they do?
At least 10 (to test fatigue)
Guidelines suggest stroke patients should have a swallowing assesment within how long of arriving in hospital?
4hours
Which area of the cortex organises the patterned response in swallowing?
Brain stem central programme generator (CPG)
Why is the LES needed? What happens if it is not fully functional?
As pressure in stomach is slightly higher than in oesophagus
If pathology then = acid reflux
Define achalasia
Failure of a ring of muscle fibres (such as those in oesophageal sphincter) to relax
Caused by degeneration of neurons (inflammation) in oesophageal wall/ myenteric plexus
What is the best diagnostic test for achalasia?
Modified barium swallow
Look for dilated oesophagus above narrow slit
What is manometry
Catheter with sensors is passed down nose into stomach, used to asses oesophageal function
What is Barrett’s oesophagus?
What is Barrett’s oesophagus?
GORD cause’s glandular metaplasia and causes squamous epithelium to become columnar, it is precancerous, leading to adenocarcinoma
How do you treat GORD?
Antacids (Gaviscon)
H2 receptor antagonists (cimetidine)
PPI’s (omeprazole)
What is the most common cause of oesophageal dysphagia?
GORD
The pH of saliva is found to increase with the flow rate of saliva along the salivary duct. Why?
As rate of metabolism in the salivary duct increases, secretion of bicarbonate also increases
Problems with the oral phase of swallowing commonly result in:
Aspiration pneumonia
What is the purpose of oromotor exercises?
Increase back of tongue function in holding material orally
Swallowing difficulties in the oral phase relate to…?
Difficulty moving food to the back of the mouth
What nerve innervates tensor veli palatini?
CN V3 (mandibular)
PNS and SNS cause secretion of which types of saliva?
PNS: Thin, rich in enzymes
SNS: Thick, rich in mucus
What is the function of kallikrein?
Enzyme activator of bradykinin (vasodilator)
Speech and language therapy doing oromotor exercises aims to mainly strengthen which muscle?
Suprahyoid
Where in the brain is the central program generator swallowing centre found?
Medulla oblongata
In the population of patients who experience dysphagia post stroke, what % will retain problems swallowing over the long term?
90%