Week 1 Flashcards
Describe the bones and structures that form the boundaries of the oral cavity
Anteriorly: The cavity extends from the upper and lower lips
Posteriorly: To the palate-glossal arches
Laterally: To the cheeks
The cavity “proper” is between the teeth, the vestibule is outside the teeth
Bones: Hard palate (made up of maxilla and horizontal plate of palatine), Teeth, Mandible
Describe the orientation of the B, R, A of the mandible
The Body and Ramus is divided by the Angle.
The Ramus then divides into condylar and coronoid processes
What is the importance of the Retromolar fossa on the medial aspect of the mandible?
Retromolar fossa for attachment of the lower end of the pterygomandibular raphe, between buccinator and superior constrictor
What is the importance of the mandibular foramen on the medial aspect of the mandible?
Mandibular foramen for the inferior alveolar or dental nerve to the lower teeth
What is the importance of the submandibular fossa on the medial aspect of the mandible?
Submandibular fossa for the submandibular gland
What is the importance of the mylohyoid line on the medial aspect of the mandible?
Mylohyoid line, for the attachment of mylohyoid muscle, forming the
floor of the mouth
What is the importance of the sublingual fossa on the medial aspect of the mandible?
Sublingual fossa for the sublingual gland
What is the importance of the sublingual fossa on the medial aspect of the mandible?
Sublingual fossa for the sublingual gland
What actions at the temporomandibular joint allow opening and closing of the mouth?
Closing: Retraction and elevation
Opening: Protrusion and depression
Opening of the mouth:
What is the primary muscle of the action and how?
Which joint cavity does the movement occur in?
What contributes the movement and how?
Primary muscle of opening: Lateral pterygoid muscle by drawing the draw + condyle forwards and downwards
Cavity: Movement in upper cavity
Gravity and digastric muscle contribute by rotation occurring the in lower joint cavity
Closing of the mouth (elevation):
Main muscles?
Main muscles: Medial pterygoid, masseter and temporalis
Facial muscles:
Name 4 main muscles?
Name their general attachment?
Main muscles: Buccinator, depressor anguli oris, orbicularis oris, lavator anguli oris
What is the structural similarity of the lips and cheeks?
The lips and cheeks are a “sandwich” of muscles of facial expression, with skin externally and non-keratinised, stratified squamous epithelium lining the mucous membrane internally
Buccinator:
Relation between fibres and lips
Modiolus?
How does it allow continuity between the oral cavity and the pharynx?
The upper fibres contribute to the upper lip and cross over to into the lower lip. Vice versa for the lower fibres
Modiolus= The point of cross over between the upper and lower buccinator fibres
Buccinator attaches to the maxilla and mandible but also fuses with the superior pharyngeal constrictor at the pterygo-mandibular raphe
What is the upper and lower attachments for the pterygo-mandibular raphe?
Lower: Over the retromolar fossa
Upper: Pterygoid hamulus (at the lower end of the medial pterygoid plate)
Sensation to the skin of the cheeks and lips, and the corresponding, internal mucous membrane is by branches from ???
By branches from the Maxillary and Mandibular divisions of the Trigeminal Nerve (Cranial V), V2 and V3
What is the main muscle of the floor of the mouth?
Muscular diaphragm of mainly mylohyoid (left and right)
Tongue muscles: Made up of which main muscles? Nervous supply? Muscular interplay? Actions of extrinsic muscles?
Within tongue: Genioglossus plus intrinsics
Attach to bone: Extrinsics i.e. palatoglossus; hyoglossus; styloglossus
Tongue muscles are supplied by the Hypoglossal nerve (Cranial XII), except palatoglossus which is supplied by vagus (CN X)
Muscular interplay: extrinsics alter position; intrinsics alter shape.
Upwards and backwards: Palatoglossus (from the palatine aponeurosis) and
Styloglossus (from the styloid process)
Draws the sides down: Hygoglossus
What structure divides the tongue?
The terminal sulcus divides it into an anterior 2/3 and a posterior 1/3, or pharyngeal part
Nervous supply of tongue sensation?
Ant 2/3 is via lingual (V3) for general sensation and taste
Post 1/3 glossopharyngeal (Cranial IX) for both general sensation and taste
Arterial and venous supply of the tongue?
Lingual artery (from external carotid) Deep and dorsal venous systems, then converging on the internal jugular
Tongue lymph drainage
- -> Inferior deep cervical lymph nodes
- -> Submandibular lymph nodes
- -> Submental lymph nodes
- -> Superior deep cervical lymph nodes
CROSSES MIDLINE
Mainly to deep cervical nodes to then drain into the internal jugular vein
What are the 3 salivary glands?
What is their function?
What is their nervous supply?
Parotid, submandibular and sublingual
Function: Commence digestion, lubricate food, maintain teeth/gum health
Nervous supply: Receive a parasympathetic, secretomotor supply from the Glossopharyngeal nerve (IX) and Facial nerve (VII)
Where and how does the sublingual gland drain?
Via separate ducts into the floor of the mouth
Where and how does the submandibular gland drain?
Submandibular ducts which are beside the sublingual glands but open at the papillae, either side of the frenulum
What 3 structures are contained within the parotid gland?
- Facial nerve
- Retro-mandibular vein
- External carotid artery
Two muscles of the palate?
Tensor palati
Levator palati
What makes up the Pillars of the Fauces?
Palatoglossal and Palatopharyngeal Arches with Palatine Tonsil between
Tensor palati
Attaches to the fossa above the medial pterygoid plate and to the cartilage of the auditory tube
Lies outside the med. pter. plate and outside the pharynx, until it becomes tendinous, curves around the pterygoid hamulus and flares into the soft palate as the palatine aponeurosis that attaches to the hard palate, but is free posteriorly
Levator palati
Arises from the apex of the petrous temporal bone and from the cartilage of the auditory tube
Lies inside the pharynx and inserts into the upper aspect of the palatine aponeurosis
Nervous and arterial supply of palates?
The greater and lesser palatine branches of the maxillary nerve and artery supply the hard and soft palates respectively, with an addition from the nasopalatine anteriorly
The glossopharyngeal nerve (IX) supplies the ___ and may encroach on to the soft palate – referred pain to middle ear
The glossopharyngeal nerve (IX) supplies the TONSILS and may encroach on to the soft palate – referred pain to middle ear
The Uvula receives the ___ ___ and hangs off the soft palate, contributing to its functions
The Uvula receives the MUSCULUS UVULAE and hangs off the soft palate, contributing to its functions
Changes that occur in the oral cavity during chewing and swallowing?
While chewing food, the oropharyngeal isthmus must be closed –
palatoglossus and palatopharyngeus contract to draw the palate down and the tongue slightly upwards, (i.e. towards each other), as well as drawing the palatoglossal and palatopharyngeal arches downwards and medially – like curtains
When swallowing, tensor palati makes the aponeurosis tense so that levator palati can lift it to close the nasopharyngeal isthmus
Teeth:
4 quarters of teeth?
Total?
Nervous supply?
Each quarter: Molars – 3 Premolars – 2 Canine – 1 Incisors – 2
Total – 8
X4 = 32
The upper teeth are supplied by the alveolar (dental) branches of the maxillary nerve (V2) that also supply the maxillary sinus. The lower teeth are supplied by the inferior alveolar (dental) branch of V3
What is the difference between the piriform fossa and the larnygeal inlet?
Piriform fossa – between the quadrangular membrane of the larynx and the side wall of the pharynx
The laryngeal inlet is between the aryepiglottic folds
What makes up the pharyngobasilar fascia? 4
Superior, middle and inferior constrictors
+ Elevators
What are the 4 points of pharyngeal attachment?
- Medial pterygoid plate of sphenoid
- Pharyngobasilar fascia attaches to the cartilage of the auditory tube
- Levator Palati arises from the apex of the petrous temporal bone, inside is the pharyngeal attachment
- The fascia, and the posterior, midline pharyngeal raphe formed by the constrictors attaches to the pharyngeal tubercle
3 structural features of the hyoid bone?
Body
Greater horn
Lesser horn
The stylohyoid ligament attaches to the lesser horn to suspend the hyoid from the styloid process of the skull
What are the attachments of the pharyngobasilar fascia and the 3 constrictors?
- Pharyngobasilar fascia attaches to the medial pterygoid plate (posterior nasal choanae), internal to the attachment of
- Superior constrictor, which continues to form the pterygo-mandibular raphe with buccinator
- Middle constrictor attaches to the hyoid bone (greater and lesser horns) and stylohyoid ligament
- Inferior constrictor attaches to the oblique line of the thyroid cartilage (thyropharyngeus), the cricoid cartilage (cricopharyngeus) and to the fascia on cricothyroid
The free, lower edge of which structure contributes to the palatopharyngeal sphincter that separates the naso from the oropharynx during swallowing?
The superior constrictor
What structure fills the gap above superior constrictor and then lies internal to it?
The pharyngobasilar fascia
What seals the “Gap” below the superior constrictor?
“Gap”, sealed by tongue muscles, fascia and mucous membrane, but allowing neurovascular structures to enter the oral cavity
What structure is between Buccinator and Superior constrictor?
Pterygomandibular raphe
What nerve supplies:
- Cricothyroid
- Larynx
- Sensation to larynx above vocal folds
External laryngeal nerve to cricothyroid
Recurrent laryngeal nerve passing deep to inf constrictor to reach the larynx
Internal laryngeal nerve – sensation to larynx above the vocal folds
_____ fascia lies externally, all around the muscular pharynx and blends with the pretracheal fascia
Buccopharyngeal fascia lies externally, all around the muscular pharynx and blends with the pretracheal fascia
What prevents air being drawn into the stomach during inhalation?
The inferior constrictor has a lower, circular part, crico-pharyngeus that forms a spinster around the upper oesophagus
What nerve supplies all the pharyngeal constrictors?
The pharyngeal branch of the vagus (X)
What is a potential consequence of uncoordinated contraction of cricopharyngeus?
May excessively raise pressure in the pharynx
At which point does the superior constrictor layer end?
What is it’s importance?
The cricopharyngeal sphincter (which leaves only 2 layers, the middle and inferior constrictor)
This allows a potential weakness (The dehiscence of Killian) through which a pharyngeal diverticulum may occur, particularly in cricopharyngeal incoordination
What are the points of insertion of the pharyngeal elevators?
Importance?
From skull to fan out into the inner surface of the pharynx. May send some fibres to the thyroid cartilage as well.
** ensures simultaneous elevation of the pharynx and larynx
Name the pharyngeal elevators?
Palatopharyngeus
Stylopharngeus
Salpingopharyngeus
All on internal pharynx aspect
Function of palatopharyngeus?
Elevates the pharynx and larynx
Draws the soft palate downwards and brings the palatopharyngeal arch towards the midline to help palatoglossus (the pillars of the fauces) separate the oral cavity from the pharynx
Main function: Pharyngeal elevator
Stylopharyngeus:
Attachments
Innervation
Main function
Stylopharyngeus descends from the styloid process to the internal pharyngeal surface
It is the only muscle supplied by the glossopharyngeal nerve (IX)
Main function: Pharyngeal elevator
Salpingopharyngeus:
Attachments?
Function?
Innervation?
From cartilage of auditory tube
Function: Elevator of pharynx and larynx. Opens auditory tube during swallowing for pressure equalisation in middle ear
Innervation: Vagus nerve
Nervous supply of palatine tonsil?
Lymph drainage?
Glossopharyngeal nerve
Lymph drainage to Jugulodigastric node
Swelling of which two tonsils may cause obstruction of the airway and auditory tube and why?
Causing…
The pharyngeal tonsil/ adenoid on the roof of the nasopharynx,
and also the tubal tonsil as they are at the opening of the auditory tube
Causing?
-Mouth breather
-Middle ear infection
What is the vallecula?
The vallecula is a pit or fossa between the tongue and epiglottis, waiting for foreign bodies!
Arterial supply of the upper and lower pharynx?
Upper pharynx - branches of the external carotid artery
Lower pharynx – branches of the inferior thyroid branch of thyrocervical from subclavian
Venous drainage of the pharynx?
Include pterygoid plexus but essentially converges on the facial and internal jugular veins
Lymph drainage of pharynx>?
Includes:
- Retropharyngeal nodes
- Paratracheal nodes
- Infrahyoid nodes
To converge on the deep cervical nodes
Which parts of the pharynx receive their sensory supply by the following nerves:
- Glossopharyngeal (IX)
- Vagus (X)
- Maxillary (V2)
Oropharynx, palatine tonsil, inferior aspect of soft palate and posterior 1/3 tongue – Glossopharyngeal (IX)
[Referred pain to middle ear]
Laryngopharynx, vallecula and epiglottis - Vagus (X)
Nasopharynx – Maxillary (V2)
Motor supply of the pharynx?
PS, secretomotor- Vagus(X) and Facial (VII)
Musculature- Vagus except stylopharyngeus which is glossopharyngeal
5 stages of swallowing
- The bolus is pushed towards the back of the oral cavity by raising the tip and body of the tongue upwards towards the palate – mylohyoid and tongue intrinsic muscles
- Styloglossus pulls the tongue upwards and backwards to tip the bolus through the oropharyngeal isthmus and into the pharynx
- The soft palate is tensed (tensor palati) and elevated (levator palati) to sit within Passavant’s ridge and separate the naso from the oropharynx
The palatoglossal and palatopharyngeal arches relax and move laterally - The pharynx and larynx have already been elevated by the longitudinal muscles - stylopharyngeus, salpingopharyngeus and palatopharyngeus; stylohyoid and digastric may also help
- Relaxation of the elevators allows the pharynx and bolus to descend, while sequential contraction of the constrictors pushes the bolus towards the oesophagus
What are the systems enquiry questions for the HPC GI?
- Abdominal pain
- Anorexia and weight change
- Dyspepsia / Indigestion
- Dysphagia
- Nausea and vomiting
- GI tract bleeding
- Jaundice
- Change in bowel habit – constipation / diarrhoea
Always remember RED FLAGS
What are the systems enquiry questions for the HPC of GU?
- Dysuria – pain / burning passing urine
- Urinary frequency – need to go more often
- Urgency – need to go NOW
- Hesitancy – want to go, but it won’t start
- Nocturia- passing urine at night
- Urinary flow - strength of urinary stream (mainly men)
- Incontinence – stress or urge or mixed
- Haematuria – blood in urine. Can be microscopic or macroscopic
- Loin pain - Pain at the side of the back , below the ribs
What are the questions to ask regarding pain?
Socrates
- Site
- Onset
- Character
- Radiation
- Associated symptoms 6. Timing
- Exacerbators/relievers 8. Severity
What are the names of the 9 regions for identifying pain?
Right hypochondrium Epigastric region L hypochondrium R flask Umbilical region L flank R iliac fossa Hypogastric/ suprapubic region L iliac fossa
What are the names of the 4 quadrants?
Right upper quadrant
Left upper quadrant
Right lower quadrant
Left lower quadrant
What condition do the following pain radiations suggest:
– Radiation to the back
– Shoulder tip
– Radiation from loin to groin
– Radiation to the back – pancreatitis
– Shoulder tip- diaphragmatic irritation
– Radiation from loin to groin- renal colic (kidney stone)
What re 5 associated symptoms to GI pain?
– Sweating / Fevers – Vomiting /nausea – Diarrhoea – Urinary symptoms – Vaginal bleeding / discharge
WEIGHT LOSS **
Name 5 common exacerbates and receivers for GI pain?
Common exacerbating factors: – Eating/noteating – Movement/ lack off – Position – Exercise(thinkcardiacdisease) – Urination/menstruation
Common relieving factors: – Eating/noteating – Vomiting/openingbowels – Movement/lackofmovement – Position
4 causes of weight gain
– Fluid gain e.g. cardiac failure, liver disease, nephrotic syndrome – Hypothyroidism – Depression – Increased energy input/ output ratio
5 causes for unexplained weight loss
– Malignancy
– Malabsorption e.g. chronic pancreatitis / coeliac disease / Crohn’s disease
– Metabolic diseases e.g. diabetes, hyperthyroidism, renal disease, chronic infection (TB/ HIV)
– Psychiatric causes e.g. depression / dementia / anorexia nervosa
– Malnutrition
Dyspepsia?
Indigestion
Symptoms of dyspepsia?
Heartburn, acidity, pain, discomfort, nausea, wind, fullness or belching
What is dyspahgia?
Sensation of obstruction during passage of liquid or solid
food through pharynx or oesophagus
Can be confused with globus
Causes of dysphagia: Oral (2) Neurological (2) Neuromuscular (4) Mechanical (5)
Oral:
Painful mouth ulcers
Tonsillitis / pharyngitis / glandular fever
Neurological:
CVA
Bulbar or pseudobulbar palsy
Neuromuscular:
Achalasia
Pharyngeal pouch Myasthenia Gravis
Diffuse oesophageal spasm
Mechanical: Oesophageal carcinoma Peptic oesophagitis Benign stricture Extrinsic compression (e.g. lung tumour, lymph nodes, goitre)
What is haematemesis?
Causes?
Vomiting blood - fresh red or “coffee-ground)
Causes: Gastric/duodenal ulcer, gastric erosions, varices
Sign and cause for upper GI bleeding?
Malaena: Passage of black tarry stools.
Usually secondary to bleed in oesophagus, stomach or duodenum. Caused by peptide ulceration
Sign and cause of lower GI bleeding?
Questions to ask?
Associated symptoms?
Fresh red blood
Questions to ask:
– Duration and frequency? / Is it mixed with stool? / associated symptoms?
Associated symptoms:
– E.g. Diarrhoea, constipation, abdominal pain, change in bowel
habit, weight loss, rectal / anal pain
Causes:
– Haemorrhoids / anal fissure / diverticular disease / large bowel polyps or carcinoma / inflammatory bowel disease
Jaundice: What is it? Causes? Questions to ask? Painless jaundice suggests..
Jaundice: Yellow discolouration of sclerae/skin
Causes: Pre-hepatic/ hepatic/ post-hepatic
Questions to ask:
- Duration?
- Associated symptoms?
- Colour of stool and urine
- Travel
- Consumption of shellfish
- Blood transfusion
- Alcohol consumption
- Changes in medications
- Unprotected sex
Painless jaundice suggests carcinoma of head of pancreas
Common causes of constipation?
Diet/dehydration Painful anal conditions Immobility Medication e.g. opiates Hypothyroidism Colonic / rectal carcinoma Neuromuscular e.g. spinal cord disease / Parkinson's disease Hypercalcaemia IBS
Common causes of diarrhoea
– Diet
– Stress
– Infection e.g. viral gastroenteritis / food poisoning
– Inflammation e.g. ulcerative colitis / Crohn’s
– Endocrine e.g. hyperthyroidism
– Malabsorption e.g. coeliac disease / pancreatic disease
– Medication
– Irritable bowel syndrome
10 Upper GI red flags
- Dysphagia
- Evidence of blood loss
- Unexplained weight loss
- Upper abdominal or epigastric mass
- Unexplained back pain
- Painless jaundice
- Persistent vomiting
- Unexplained iron deficiency anaemia
- Unexplained worsening dyspepsia without other symptoms if >55 yrs old
- New onset upper GI pain if >55yrs old OR if risk factor (e.g.+ve FH)
7 lower GI tract red flags?
Repeated rectal bleeding Blood mixed with stool Persistent change in bowel habit Right sided abdominal mass Palpable rectal mass Unexplained iron deficiency anaemia Past history of lower GI cancer plus any of above
What is the difference in the presentation of a lower UTI and and upper?
Lower UTI = Cystitis (bladder inflammation)
Symptoms: Dysuria, frequent urination, urgent, suprapubic discomfort, possible haematuria
Upper UTI = Pyelonephritis (kidney inflammation)
Symptoms: Loin pain, fevers, riggers, flank tenderness, urinary frequency, dysuria, possible haematuria
What is prostatism?
Symptoms of prostate enlargement:
- Irritative: Urgency/dysuria/ frequency/ nocturia
- Obstructive: Reduced force of stream / hesitancy
- Prostatitis can cause perineal pain
Causes for loin pain?
Pyelonephritis Renal calculi (loin to groin) Hydronephrosis Renal tumour Renal abscess Referred pain from back
Causes of haematuria
UTI Urinary tract calculi Bladder carcinoma Glomerulonephritis Renal carcinoma Benign prostatic hypertrophy Prostatic carcinoma
Which type of haematuria much be investigated further
Macroscopic
Persistent microscopic
What are the GU red flags
- Any age with painless macroscopic haematuria
- Haematuria and symptoms of UTI but sterile urine
- Testicular swelling
- Abdominal mass from urinary/genital tract
- Hard irregular prostate
- Normal prostate, but rising / raised age specific PSA (prostate specific antigen) with or without lower urinary tract symptoms
- Symptoms and high PSA levels
- Postmenopausal bleeding
- Persistent intermenstrual bleeding
- Palpable pelvic mass/cervical lesion/vulval mass
Function of the stomach and it’s exocrine secretions
Stomach: Store, mix, dissolve and continue digestion of food.
Function of the stomach and it’s exocrine secretions
Stomach: Store, mix, dissolve and continue digestion of foo. Regulates emptying of dissolved food into small intestine.
Exocrine secretions:
HCl: Solubilisation of food particles, kill microbes
Pepsin: Protein-digesting enzyme
Mucus: Lubricate and protect epithelial surface
Function of the liver and its exocrine secretions
Liver: Secretion of bile
Exocrine secretions:
Bile salts: Solubilise water-insoluble fats
Bicarbonate: Neutralize HCl entering small intestine from stomach
Organic water products and trace metals: Elimination in faeces
Gall bladder function:
Store and concentrate bile between meals
Function of small intestine and it’s exocrine secretions
SI: Digestion and absorption of most substances; mixing and propulsion of contents.
Function of small intestine and it’s exocrine secretions
SI: Digestion and absorption of most substances; mixing and propulsion of contents.
Exocrine secretions:
Enzymes- Food digestion
Salt and water- Maintain fluidity of luminal contents
Mucus- Lubrication
Function of large intestine and its exocrine secretions
LI: Storage and concentration of undigested matter, absorption of salt and water, mixing and propulsion of contents, defecation
Exocrine secretion: Mucus for lubrication
Function of large intestine and its exocrine secretions
LI: Storage and concentration of undigested matter, absorption of salt and water, mixing and propulsion of contents, defecation
Exocrine secretion: Mucus for lubrication
What are the 5 major physiological processes of the GI system
Motility Secretion Digestion Absorption Excretion
What are the 5 major physiological processes of the GI system
MOTILITY
Propulsion of ingested food from mouth to rectum, mixing and reducing in size to optimise time for absorption and digestion
SECRETION
Salivary glands, stomach, small intestine, pancreas and liver all add fluid, electrolytes, enzymes and mucus
DIGESTION
Ingested food is digested into absorbable molecules
ABSORPTION
Nutrients, electrolytes and water are absorbed from the intestinal lumen into the bloodstream
EXCRETION
What are the major immunological and non-immunological defence mechanisms of the GI?
Immunological mechanisms: Mucosal immune system (gut-associated lymphoid tissue, GALT).
These are aggregate of lymphoid tissue i.e. Peyer’s patches and diffuse populations of immune cells.
Provides: Protection against microbial pathogens, mediates immunological tolerance to dietary substance sea gut bacteria
Non-immunologic mechanisms: Gastric acid, mucin, peristalsis and the epithelial cell layer barrier
What are the layers of the GI wall?
- Muscular mucosal, epithelium, lamina propria
- Submucosa
- Submucosal nerve plexus
- Circular muscle (muscular externa)
- Myenteric plexus
- Longitudinal muscle
- Serosa
What is the lamina propria?
Underlying loose connective tissue with capillaries, enteric neurones and immune cells
What is the muscular mucosal?
Thin smooth muscle layer of the mucosa
What is contained within the submucosa?
Loose connective tissue Larger blood vessels Lymphatics Secretory glands Enteric neurones in the submucosa
What is the muscular externa?
Inner layer of circular muscle
Outer layer of longitudinal muscle
Enteric neurones between the muscle layers- myenteric plexus
What is the serosa?
Outer layer of connective tissue covered with squamous epithelial cells
What is the intrinsic component of the innervation of the GI tract?
What are the two plexuses? Where are they found and what do they do?
ENTERIC NERVOUS SYSTEM
- The submucosal plexus (Meissner’s plexus). In the LI and SI. Primarily regulates glandular, endocrine and epithelial secretions
- The myenteric plexus (Auerbach’s plexus). Between the circular and longitudinal muscle layers throughout he GI tracts. Primarily consists of motor neurones.
Describe where the extrinsic nervous system secretes neurotransmitters within the GI
PS from Vagus or pelvic nerve: Synapses of ACh in myenteric and submuscosal plexus. Released into circular and longitudinal muscle and mucosa.
Symp from sympathetic ganglia: NE synapse in myenteric and submucosal plexuses. Released into the circular muscle and mucosa
Which GI reflexes are integrated within the enteric nervous system?
Reflexes controlled secretion, peristalsis, mixing, local inhibitory actions
Which GI reflexes are from the GI tract to prevertebral sympathetic ganglia and then back to the GI tract?
Reflexes that transmit signals to other areas of the GI tract
- Gastrocolic reflex (stomach – colon)
- Enterogastric reflexes ( stomach and colon inhibiting gastric motility)
- Colonoileal reflexes (inhibition of ileal emptying)
Which GI reflexes from the GI tract to the brain stem or spinal cord and then back to the GI tract?
(1) Reflexes from stomach and duodenum to brain stem and back to stomach to control gastric motor and secretory activity
(2) Pain reflexes causing general inhibition of entire GI tract
(3) Defecation reflexes from the colon and rectum that travel via the spinal cord back to produce powerful colonic, rectal and abdominal contractions
What is the
(1) Source
(2) Target
(3) Action
of the following GI hormone: Gastrin
(1) Source
G cells in the atrium of stomach
(2) Target
Parietal cells in body of stomach
(3) Action
Increases H+ secretion
Stimulates growth of gastric mucosa
What is the
(1) Source
(2) Target
(3) Action
of the following GI hormone:
Cholecystokinin (CKK)
(1) Source
I cells in duodenum and jejunum; neurones in ileum and colon
(2) Target
Pancreas and gall bladder
(3) Action
Increases enzyme secretion
Increases contraction
What is the
(1) Source
(2) Target
(3) Action
of the following GI hormone:
Secretin
(1) Source
S cells in SI
(2) Target
Pancreas and stomach
(3) Action
Increases HCO-3 and fluid secretion by pancreatic ducts
Decreases gastric acid secretion
What is the
(1) Source
(2) Target
(3) Action
of the following GI hormone:
Gastric inhibitory peptide
(1) Source
K cells in duodenum and jejunum
(2) Target
Pancreas and stomach
(3) Action
Exocrine: Decreases fluid absorption
Endocrine: Increases insulin release
Decreases gastrin release
What is the
(1) Source
(2) Target
(3) Action
of the following GI hormone:
Motillin
(1) Source
Endocrine cells in upper GI tract
(2) Target
Oesophageal sphincter
Stomach
Duodenum
(3) Action
Increases smooth muscle contraction
What is the
(1) Source
(2) Target
(3) Action
of the following GI hormone:
Glucagon
(1) Source
Alpha cells of pancreatic islets of Langerhans
(2) Target
Liver
(3) Action
Increases glycogenolysis and gluconeogenesis
What is the
(1) Source
(2) Target
(3) Action
of the following GI hormone:
Guanylin
(1) Source
Ileum and colon
(2) Target
Intestine
(3) Action
Increases fluid absorption
What is the
(1) Source
(2) Target
(3) Action
of the following GI hormone:
Neurotension
(1) Source
N cells of the ileum
(2) Target
Smooth muscle and vagus
(3) Action
Relaxes smooth muscle
Decreases gastric acid secretion
What is the
(1) Source
(2) Target
(3) Action
of the following GI paracrine:
Somatotrophin
(1) Source
D cells of stomach and duodenum
B cells of pancreatic islets
(2) Target Stomach Intestine Pancreas Liver
(3) Action
Decrease gastric release
Increases fluid absorption, decrease fluid secretion
Decrease endocrine and exocrine secretions
Decrease bile flow
What is the
(1) Source
(2) Target
(3) Action
of the following GI paracrine:
Histamine
(1) Source
Endocrine cells of the gastric mucosa (esp H+ secreting region of the stomach)
(2) Target
Stomach
(3) Action
Stimulates H+ secretion from parietal cells in the stomach
What is the
(1) Source
(2) Target
(3) Action
of the following GI neurocrine:
ACh
(1) Source
Cholinergic neurons
(2) Target Smooth muscle Salivary glands Stomach Pancreas
(3) Action
Contraction of GI wall, relaxation of sphincters
Increases secretion of salivary glands, stomach and pancreas
What is the
(1) Source
(2) Target
(3) Action
of the following GI neurocrine: NA (NE)
(1) Source
Adrenergic neurons
(2) Target
Smooth muscle and salivary glands
(3) Action
Relaxation of GI wall and increases saliva secretion
What is the
(1) Source
(2) Target
(3) Action
of the following GI neurocrine:
Vasoactive intestine peptide
(1) Source
Enteric nervous system
(2) Target
Smooth muscle
Pancreas and intestine
(3) Action
Smooth muscle relaxation
Increase intestine and pancreas secretion
What is the
(1) Source
(2) Target
(3) Action
of the following GI neurocrine:
Gastrin released peptide (GRP)
(1) Source
Neurons of the gastric mucosa
Vagal nerve endings
(2) Target
G cells in the Antrum of the stomach
(3) Action
Increases gastrin secretion
What is the
(1) Source
(2) Target
(3) Action
of the following GI neurocrine:
Enkephalins (opiates)
(1) Source
Neurons of the mucosa and smooth muscle
(2) Target and action
Smooth muscle - relaxation
Intestinal secretion - decreases
What is the
(1) Source
(2) Target
(3) Action
of the following GI neurocrine:
Neuropeptide Y
(1) Source
Neurons of the mucosa and smooth muscle
(2) Target and action
Smooth muscle - relaxation
Intestinal secretion - decreases
What is the
(1) Source
(2) Target
(3) Action
of the following GI neurocrine:
Substance P
(1) Source
Co-secreted with ACh
(2) Target and action
Smooth muscle - contraction
Salivary glands - Increases secretion
What is the WHO constitution of health and human rights in 2006?
The enjoyment of the highest attainable standard of health issue is one of the fundamental rights of every human being without distinction of race, religion, pollination belief, economic or social condition
Human rights are inherent, interrelated, interdependent and indivisible
Why are infectious diseases a global ethical issue?
• “Unrivalled consequences”
• Control measures raise important questions re: violation of important rights
– Right to freedom of movement – Right to privacy
– Right to informed consent
• Justice
• Do not respect boundaries
Ethics of isolation and quarantine: Michael Selgelid lists 6 considerations
- Must be effective in controlling the disease
- If less restrictive measures achieve the same effect, use them
- Consequences of not quarantining must be severe
- Must be implemented in an equitable manner
- Must be minimally burdensome
- Those contained must receive compensation
Isolation = have disease Quarantine = exposed to disease, possibly have it
Name 3 Good moral reasons for carrying out research in developing countries?
However, name 3 factors that will play a part?
- Global health inequalities
- Disproportionate burden of disease
- Value of research in developing countries*
Factors:
• Less stringent ethical standards
• Cost
• Number of participants, particularly drug-naive
What was the key trial in the reviewing the control in clinical trials?
076 protocol (1994) of AZT and maternal-child transmission of HIV
Which is the correct control to use?
- Placebo vs experimental treatment
- Standard treatment vs experimental treatment
Participants were given placebo which violates declaration of Helsinki
What was the update to the declaration to Helsinki in 2013?
Flexibility
“Where for compelling and scientifically sound methodological reasons the use of any intervention less effective than the best proven one, the use of placebo, or no intervention is necessary to determine the efficacy or safety of an intervention”
Important considerations in research and clinical trials
• Ethical review & protection of participants
• Healthcare infrastructure
– NB controversy over “controls” in clinical trials
• Valid consent
• Community engagement
• Benefits to participants after trial/ research is over
• The importance of collaborating with local scientists
What are the medical ethics in times of armed conflict?
Identical to medical ethics in times of peace, as stated in the International Code of Medical Ethics of the WMA.
What inequalities and issues were highlighted by the ebola outbreak?
– Ebola outbreak centred around some of the poorest countries in the world
• Lack of basic healthcare facilities to treat patients
• Lack of basic disease response infrastructure
– Originally not regarded as a Western problem (until cases
emerged in the US and Spain)
– Should Western healthcare workers working in affected countries be transferred to back to Western healthcare facilities?
– Who should receive the limited (experimental) treatments?
What were the research issues associated with drug administration during the ebola outbreak?
Panel was convened by the WHO in August 2014 to determine whether it was ethical to administer these despite the potential for unknown adverse effects and to determine who should receive priority.
Concluded ebola outbreak was exceptional and it was ethically acceptable to offer unproven interventions but ethical standards must be maintained.
What structures are beneath the 4 quadrants of the abdomen?
RUQ: Liver and gall bladder
RLQ: Ileum, caecum, appendix
LUQ: Jejunum
LLQ: Sigmoid colon
Which 4 lines are used to determine the 9 regions of the abdomen?
Midclavicular Lines (2)
Subcostal Plane just below the costal margin at L3
Inter (trans) tubercular / Supracristal plane between the iliac crests at L4/5
What is the umbilicus?
A scar representing the site of attachment of the umbilical cord in the foetus
How is the superficial fascia of the abdominal wall divided?
- Camper’s fascia: a superficial, fatty layer
2. Scarpa’s fascia: A deeper membraneous layer
What is the composition of the internal fascia in the abdominal wall?
- There are very thin, negligible layers of fascia between the muscles
- Deep to the muscles (but outside the peritoneum), there is a layer of endo-abdominal or transversals fascia
- Variable exztraperitoneal fat which is immediately external to the peritoneum
What happens to the abdominal superficial fascia on descending to the scrotum?
Camper’s is replaced by dartos
Scarpa’s extends into the penis and scrotum, to become, Colle’s perineal fascia. This fuses with the fascia lata of the thigh below the inguinal ligament
What is distinctive about bruising that is trapped under scrap’s fascia?
On front only
“Blue swimming shorts”
In the abdomen, what fascia layers are found deep to the muscle layer?
Transversalis
Extraperitoneal fascia
Thoracolumbar fascia passes from the ____ ____ to the 12th rib and is in 3 layers (___, ___, ____) that surround the back muscles and fuse together and give origin to transversus ______ and internal oblique, but not external oblique
Thoracolumbar fascia passes from the iliac crest to the 12th rib and is in 3 layers (anterior, middle and posterior) that surround the back muscles and fuse together and give origin to transversus abdominis and internal oblique, but not external oblique
What is the transversals fascia?
A thin layer of fascia that lines the transversus abdominis muscle and is continuous with a similar layer lining the diaphragm and the iliac muscle.
What is the extraperitoneal fascia?
A thin layer of fascia that contains a variable amount of fat and lies between the transversal is fascia and the parietal peritoneum.
What are the anterior abdominal wall muscles?
3 broad, thin sheets: (sup) 1. External oblique 2. Internal oblique 3. Transversum abdominis
A vertical muscle Rectus Abdominis (and Pyramidalis)
What are the functions of the anterior abdominal wall muscles?
- Support abdominal contents and raise intra-abdominal pressure, withstanding pressure from descent of the diaphragm
- Support vertebral column, flexing, laterally flexing and rotating the trunk against resistance
- Respiration
External oblique:
Attachments?
Fibre direction?
Nerve supply?
Attachments:
From- Lower 8 ribs, lateral lip of iliac crest, aponeurosis to linea alba via rectus sheath
To- forms the inguinal ligament
Fibre direction: Downwards and medially
Nerve supply: T7-12
What is the inguinal ligament? What is it’s attachments?
Continues as?
Inrolled, inferior edge of external oblique.
From ASIS to pubic tubercle
Continues as lacunar and pectineal ligaments
What is the superficial ring?
Triangular opening in external oblique aponeurosis with its base at the pubic crest
Internal oblique:
Attachments?
Fibre direction?
Nerve supply?
Attachments:
From- Thoracolumbar fascia, iliac crest, lateral 2/3rd of inguinal ligaments, lower 3/4 ribs and CC’s, aponeurosis
To- Linea alba via rectus sheath, pubic crest behind the superficial inguinal ring via conjunct tendon
Fibres pass upwards and medially to ribs,
but downwards to conjoint tendon
Nerve supply: T7 to 12 plus L1 via iliohypogastric nerve to the fibres that form the conjoint tendon
What is the consequence of injury to the iliohypogastric nerve?
Weakness on the conjoint tendon and predisposed to inguinal hernias
Transversus abdominis:
Attachments?
Fibre direction
Nerve supply?
Attachments:
From-Thoracolumbar fascia, iliac crest, lateral 1/3rd or half of inguinal ligament, lower 6 ribs + CCs, aponeurosis
To- Linea alba via rectus sheath, pubic crest behind the superficial inguinal ring via conjoint tendon
Fibres pass transversely to ribs,
linea alba and conjoint tendon
Nerve supply: T7 to 12, plus L1 via the iliohypogastric nerve to the fibres that form the conjoint tendon
What is the conjoint tendon formed from? Attachements?
Formed from the aponeuroses of internal oblique and transversus abdominis
It attaches to the pubic crest and pectineal line behind the superficial inguinal ring, therefore supports the ring
Rectus abdominis:
Attachments?
Fibre direction?
Nerve supply?
Attachments: CC of ribs 5-7, diploid, pubic symphysis, pubic crest and pectineal line
Fibres pass vertically with tendinous intersections
Nerve supply: T7 to 12
What is pyramidalis?
A small triangle anterior to RA.
From pubic crest to linea alba
What forms the rectus sheath?
Each rectus abdominis is enclosed anteriorly and posteriorly between the bilaminar aponeuroses of the EO, IO and TA. This forms the rectus sheath
In the midline they fuse as the linea alba
What happens to the rectus sheath at the arcuate line?
All aponeuroses pass anteriorly and the posterior sheath ends.
This allows inferior epigastric vessels to enter the sheath behind rectus abdominis
Inguinal canal:
What is it?
Created by?
Contains?
What is it?
An oblique passage through the anterior abdominal wall. Has 2 openings, deep and superficial rings. Each ring is protected by 2 of the 3 muscles
Created by the descent of the testis, pushing through the 3 layers of the muscle
Contains:
- Vas deferens and testicular vessels in male (round ligament in females)
- Ilio-inguinal nerve
- Genital branch of genitofemoral nerve
Superficial inguinal ring:
Location?
Structural features?
Location: Triangle in external oblique at base of pubic crest
Structural features: Medial and lateral crura. Supported from behind by conjoint tendon (IO + TA)
Deep inguinal ring:
What is it?
Transmits which structures?
Position?
Opening in the transversal is fascia. Overlain by internal and external oblique.
Trasmits vas deferens and gonadal vessels (in spermatic cord)
Position: Lies lateral to the inferior epigastric vessels, half way between the ASIS and the pubic tubercle
What muscles make up the walls, roof and floor of the inguinal canal?
Anterior wall: EO with IO laterally
Posterior wall: Conjoint tendon, transversals fascia laterally
Roof: Arching fibres of IO and transversus abdominis
Floor: Inrolled lower edge of inguinal ligament, strengthened medially by lacunar ligament
What is a hernia?
A protrusion of a viscus through the wall of its containing cavity
What is the normal location of an inguinal and femoral hernia?
Inguinal hernia: Above and medial to the pubic tubercle
Femoral hernia: Passes through the femoral canal and appears below and lateral to the pubic tubercle
What is the difference between a direct and indirect inguinal hernia?
Direct: Through the posterior wall of the inguinal canal medial to the inferior epigastric vessels. Ends up in the scrotum, parallel to spermatic cord and with it’s own covered of peritonium, transversals fascia, conjoint tendon and external oblique as external spermatic fascia
Indirect: Through the deep inguinal ring lateral to the inferior epigastric vessels. Bowel in the spermatic cord, covered by parietal peritoneum and passing through deep inguinal ring of transversalis fascia.
What forms internal spermatic fascia at the deep ring?
Transversalis fascia
How will a hernia that causes obstruction present?
Colicky abdominal pain
Distension
Vomiting
Hernia will be tense, tender and irreducible
How will a hernia that causes strangulation present?
Red and tender
For the following incisions, name their location and 1 use:
- Midline
- Paramedian
- Transverse
- Subcostal
- Gridiron
- Pfannenstiel
- Midline
Vertically at midline, skirting around umbilicus
Use: Abdominal operations when full access is required - Paramedian
2.5-4cm parallel and lateral to midline
Use: Ops that required full access to half of abdomen - Transverse
Sup to umbilicus, transversely through either one or both rectus muscles
Use: Ascending colon - Subcostal
2.5 cm below the xiphisternum and extends parallel to, and 2.5 cm below the costal margin.
Use: Biliary surgery on RHS - The Gridiron
Centred at McBurney’s point (two-thirds of the way laterally along the line from the umbilicus to the anterior superior iliac spine). Or horizontal incision (Lan approach)
Uses: Appendicectomy - Pfannenstiel
5cm above pubic symphysis, transverse cut
Use: Caesarean sections
Name the 3 muscles of the posterior abdominal wall
- Quadratus lumborum
- Psoas major, possibly with poses minor overlying it
- Iliacus
(Diaphragm contribute to the upper, posterior abdominal wall)
Function of the posterior abdominal wall muscles
Quadratus lumborum stabilises the 12th rib for diaphragmatic movement in respiration
Psoas major and iliac pass to the lesser trochanter together and are powerful hip flexors
What is the position of the iliolumbar ligament?
From the transverse process of L5 to the posterior superior iliac spine and adjacent iliac crest
Quadratus lumborum:
Attachments?
Nerve supply?
Attachment:
From iliac crest, iliolumbar ligament and L5 LP
To 12th rib and L1-4 TPs
Nerve supply: T12 to L1-4
Psoas major:
Attachment?
Nerve supply?
Attachments:
From transverse processes, bodies, and intervertebral discs of 12th thoracic and five lumbar vertebrae;
To lesser trochanter of femur (with Iliacus)
Nerve supply: L1 to 3
Psoas minor:
Attachments?
Nerve supply?
Attachments:
From T12/L1 vertebral bodies
To pectineal line and iliopectineal eminence on pelvic bone
Nerve supply: L1
(Absent in 50%)
Iliacus:
Attachments?
Nerve supply?
Attachments:
From Iliac fossa
To lesser trochanter of femur (with psoas)
Nerve supply: Femoral nerve L2, 3, 4
What are the contents of the femoral sheath?
Femoral artery
Femoral vein
Femoral canal (lymphatics e.g. Cloquet’s lymph node that receives directly from the glans of penis or clitoris)
Where is the site of a femoral hernia?
Femoral sheath, below and lateral to the pubic tubercle.
This is an extension of the abdominal transversals fascia
What are the boundaries of the femoral canal?
Medial, lateral, posterior, anterior
Medial: Lacunar ligament
Lateral: Femoral vein
Posterior: Ligament for ring
Anterior: Inguinal ligament
Which nerves supply the skin and muscle of the abdominal wall?
Supplied in segments by ventral rami of the spinal nerves T7-12 and L1 (as iliohypogastric and olio-inguinal nerves)
What is the epigastric dermatome? Where does the referred pain go to?
Epigastric: T7
Referred pain: Stomach and oesophagus
Where is the umbilical dermatome? Where is it’s referred pain?
Umbilical: T10
Referred pain: Appendix, gonad, small intestine
What is the suprapubic dermatome? Where is it’s referred pain?
Suprapubic: T12
Referred pain: Lower colon, bladder, uterus
What must be down when splitting rectus abdominis surgically to avoid denervation?
The fibres must be pushed laterally towards the nerves
What is the pathways of the nerves that supply the abdominal muscles?
Anterior rami of T7-12 and L1 pass between internal oblique and transversus abdominis
Enter rectus sheath to supply rectus abdominis, from lateral to medial. T12 only supplies pyramidalis
Terminates by peircing the ant wall of the sheath and supplying the overlying skin.
Iliohypogastric nerve pierces the external oblique aponeurosis above superficial inguinal ring
Ilio-inguinal nerve emerges through superficial ring.
End by supplying the skin above the inguinal ligament
What does the iliohypogastric nerve supply?
Result of injury?
Internal oblique and Transverse abdominis fibres that form the conjoint tendon.
Injury: Weakens the conjoint tendon and pre disposal to hernia
What are the muscular branches of the lumbar plexus and which nerve fibres do they carry?
Iliohypogastric (L1) Ilio-inguinal (L1) Genitofemoral (L1, 2) Lateral Femoral Cutaneous (L2, 3) Obturator (L2, 3, 4) Femoral (L2, 3, 4)
Which muscle is the lumbosacral plexus formed in?
Psoas
What is McBurney’s point?
1/3 of the way up that line from the ASIS to the umbilicus
Note: Point of appendicectomy incisions
Which vessels provide the arterial supply to the abdominal wall?
Lower 2 posterior Intercostal arteries 4 Lumbar arteries Sup, inf and superficial epigastric artery Deep circumflex iliac artery Superficial epigastric Superficial circumflex iliac artery
Superior epigastric artery:
Pathway?
Supplies which muscles?
Is a branch of the internal thoracic (mammary) artery, and enters the upper part of the rectus sheath between the sternal and costal origins of the diaphragm
It descends behind the rectus muscle, SUPPLYING the upper
central part of the anterior
abdominal wall, and anastomoses
with the inferior epigastric artery
Branches from the musculophrenic branch of the internal thoracic artery SUPPLY the upper, lateral abdominal wall
Inferior epigastric artery:
Branch of which vessel?
Pathway?
Supplies?
The inferior epigastric artery is a branch of the external iliac
It runs upward and medially along the medial side of the deep inguinal ring and pierces the transversalis fascia to enter the rectus sheath anterior to the arcuate line.
Supplies:
-Lower central part of the anterior abdominal wall
Anastomoses with sup epigastric artery
Deep circumflex iliac artery:
Branch from which vessel?
Pathway?
Supplies what?
Branch of external iliac just above the inguinal ligament
Pathway: Runs upwards and laterally towards the ASIS, then along iliac crest
Supplies: Lower, lateral part of the abdominal wall
The superficial epigastric and superficial circumflex iliac arteries:
Branch of which vessel?
Supply what?
Branch from femoral just below inguinal ligament
Supply: Lower abdominal wall
Which vessels pass forwards between the muscle layers and supply the lateral abdominal wall?
Lower 2 posterior intercostal arteries
The 4 lumbar arteries
What is the structure of the abdominal wall venous drainage system?
The veins radiate out from the umbilicus to drain into the femoral and external iliac veins inferiorly and the internal thoracic and axillary veins superiorly.
Para-umbilical veins connect the system through the umbilicus to the portal veins of the liver
The superficial epigastric and superficial circumflex iliac veins drain in to the proximal end of the great (long) saphenous vein along with the superficial and deep external pudendal veins; these 4 veins are important in varicose vein surgery
What vessel forms the portosystemic venous anastomosis?
What is the result of obstruction of this vessel?
Para-umbilical veins connect the system through the umbilicus to the portal veins of the liver
If obstructed, resulting in Caput Medusae
What is the superficial lymphatic drainage of the abdominal wall?
Anteriorly:
Above umbilicus –> Axillary nodes (Anterior/pectoral group)
Below umbilicus –> Superficial inguinal nodes
Posteriorly:
Above iliac crest –> Axillary nodes (Posterior/ subscapular group)
Below iliac crest –> Superficial inguinal nodes
What is the lymph drainage pathway after the superficial inguinal nodes?
The superficial nodes drain to the deep inguinal nodes (in the femoral canal), which drain to external iliac and then para-aortic nodes
What is the lymph drainage of the deep abdominal wall?
Inferiorly: To external iliac and then para-aortic nodes
Superiorly: To parasternal nodes alongside the internal thoracic artery and then mediastinal nodes
Which parts of the contractile tissue ISN’T smooth muscle?
Pharynx
Upper third of oesophagus
External sphincter
What are the stages of calcium activation of myosin in smooth muscle?
Calmodulin + Ca2 binds to inactive myosin light chain kinase, activating it,
Active myosin light chain kinase + Pi activates and phosphorylates myosin
What are the stages of smooth muscle relaxation?
- Decrease in Ca2+
- Ca2+-Calmodulin –> Calmodulin
- Active –> inactive myosin light chain kinase
- Active phosphorylated –> inactive myosin via myosin phosphatase
What is important about the origin and frequency of slow waves in smooth muscle?
Origin and initiation: Interstitial Cells of Cajal (ICC) These are pacemaker cells found in the myenteric plexus that generate slow waves
Frequency:
Intrinsic rate varies from 3-12 per minute.
Stomach- 3 waves per min
Duodenum- 12 waves per min
Smooth muscle slow wave frequency unaffected by neural or hormonal input but….
Neural and hormonal input influences action potential frequency (strength of contraction)
What are the steps in slow wave generation in the GI tract muscle?
Depolarisation due to the cyclical opening on voltage gated Ca2+ channels.
- Increase in the intracellular Ca2+ concentration
- Opening of Ca2+ dependent K+ channels
- Increased K+ permeability leads to slow hyperpolarisation
- Voltage gated Ca2+ channels close and intracellular Ca2+ concentration falls
- Ca2+ dependent K+ channels close
- Voltage gated Ca2+ channels open
What is the consequence of stimulation by stretch, ACh and parasympathetics on the GI smooth muscle electrical activity?
Spikes and depolarisation
What is the consequence of the stimulation by NE and sympathetics on the GI smooth muscle electrical activity?
Hyperpolarisation
Functions of chewing?
- Mixes food with salvia, mucin glycoprotein acts as a lubricant
- Reduces size of food particles, facilitates swallowing
- Mixes food components with digestive enzymes, carbohydrates with salivary amylase and fat with lipase
How is an involuntary reflex initiated during chewing?
Sensory information relayed from mechanoreceptors to the brain stem initiates a reflex oscillatory pattern of activity in chewing muscles
What are the 3 phases of swallowing?
Oral
Pharyngeal
Oesophageal
What is the pathway of the swallowing reflex?
Afferent pathway: Sensory information from touch receptors near the pharynx
Swallowing centre in the medulla and lower pons
Efferent motor pathway: involves cranial innervation of pharynx and upper oesophagus and vagal motor innervation of the lower oesophagus
What is the sequence of sphincter opening and closing in the oesophagus?
- Upper oesophageal sphincter opens to allow bolus of food to enter oesophagus
- Upper oesophageal sphincter closes
- Primary peristaltic contraction mediated by swallowing reflex involves a series of coordinated contractions creating a region of high pressure behind the bolus (accelerated by gravity)
- Lower oesophageal sphincter opens mediated by peptidergic nerves in the vagus releasing VIP (vasoactive intestinal peptide)
- Receptive relaxation of the orad region of the stomach
- Lower oesophageal sphincter closes
What is achalasia?
Leads to…
Due to..
Means: Absence of relaxation
Leads to difficulty in swallowing (i.e. dysphagia)
- Failure of the lower oesophageal sphincter to relax
- Impaired peristalsis in distal regions
Due to selective loss of neurones which regulate the lower oesophageal sphincter by released VIP (Vasoactive intestinal peptide)
What is the difference in the peritoneal cavities of males and females?
Clinical risk?
In males, the peritoneum is a closed cavity, but in females, there is communication with the exterior through the uterine tubes, the uterus, and the vagina
Risk: This may allow the spread of infection from the exterior to inside the peritoneal cavity
Where is the extraperitoneal tissue found?
Between the parietal peritoneum and the fascial lining of the abdomen and pelvic walls (transversalis fascia)
How is the peritoneal cavity divided?
Into two parts: Greater and lesser sacs
Greater sac: Main compartment and extends from the diaphragm down into the pelvis
Lesser sac: Smaller and lies behind the stomach and lesser omentum but extends slightly into the greater omentum
What structures allows free communications between the greater and less omentum?
Epiploic foramen of Winslow
What is the omenta?
Two-layered folds of peritoneum that connect the stomach and 1st part of the duodenum to other
Greater and lesser omentum
What is the greater omentum?
“Policeman of the abdomen”??
Derived from dorsal mesentery, is a large apron like peritoneal fold.
From greater curvature of the stomach and 1st part of duodenum.
Overlies transverse colon and SI
Named “policeman of the abdomen” as it is drawn to diseased or perforated structures to seal them off
Lesser omentum:
From where to where?
Other names?
Passes from the lesser curvature of the stomach an 1st part of the duodenum to the inferior border of the liver.
It may be referred to as hepatogastric and hepatoduodenal ligaments
Which terms essentially means the same as epiiploic?
Omental
What is the hepatoduodenal ligament?
The free edge of the lesser omentum containing the portal vein, hepatic artery and bile duct
What are mesenteries?
Name the 3 present in the abdomen?
Double-layered peritoneal folds that attach viscera to the posterior abdominal wall
- The mesentery (associated with the small intestine)
- Transverse mesocolon
- Sigmoid mesocolon
What is the The Mesentery?
Which structures does it cross?
Contains branches of which structures?
A fan shaped double-layered fold of peritoneum that connects the jejunum and ileum to the posterior abdominal wall.
It’s base starts at L2 and pass obliquely downwards to just above the right sacroiliac joint
It crosses the 3rd part of the duodenum, the aorta and IVC, the right gonadal vessels and right ureter
It contains branches of the SMA and SMV, with nerves and lymphatics
What is the anastomotic arcade difference between the ileum and jejunum?
The SMA branches as a series of anastomotic arcades.
Jejunum: Has few arcades with long vasa recta
Ileum: Has many arcades with short vasa recta
Sigmoid mesocolon:
What is it?
Root?
Transmits which vessels?
Sigmoid mesocolon is the double-layered fold of peritoneum that connects the sigmoid colon to the posterior abdominal wall.
Root: In the left iliac fossa, crossing the bifurcation of the left common iliac vessels and the left ureter
Transmits: The sigmoid branches of the inferior mesenteric vessels plus nerves and lymphatics
Transverse mesocolon:
Function?
Root?
The transverse mesocolon suspends the transverse colon from the posterior abdominal wall
Root: Just inferior to the pancreas and it carries branches of the middle colic vessels
Which organs are contained in the supra and infra colic compartments?
Supra: Liver, stomach and spleen
Infra: Jejunum, ileum, ascending and descending colon
Which half of the infra colic compartment has…
a paracolic gutter (left and right)
Name the spaces/gutters present within the peritoneum?
Ant right subphrenic space Post right subphrenic space Ant left subphrenic space Right paracolic gutter Left parabolic gutter
Where is the epiploic foramen?
Within the right posterior subphrenic space / hepatorenal recess / Morison’s Pouch
Name the 3 pelvic peritoneal pouches?
- The recto-uterine pounch (in females) separating the rectum from the uterus
- The rectovesical pouch (in males) separating the rectum from the bladder
- The vesico-uterine pouch (in females) separating the bladder from the uterus
Name the 3 umbilical folds and their features?
The median umbilical fold contains the urachus, which extends from the urinary bladder to the umbilicus
The medial umbilical folds are raised by the obliterated umbilical arteries, extending from the internal iliac arteries to the umbilicus
The lateral umbilical folds are raised by the inferior epigastric arteries, extending from the deep inguinal rings on each side to the arcuate lines
Which structure is truly intraperitoneal?
The ovary
Which structures are retroperitoneal?
Primarily retroperitoneal: – urinary adrenal glands kidneys ureter bladder – circulatory aorta inferior vena cava – digestive oesophagus (final part) rectum (middle 1/3)
Secondarily retroperitoneal:
– the head, neck, and body of the pancreas
– the duodenum, except for the proximal first segment, which is
intraperitoneal
– ascending and descending portions of the colon
Which is the difference in the stimuli the the parietal and visceral peritoneum are sensitive to?
Parietal peritoneum: Sensitive to pain, temperature, touch, and pressure
Visceral peritoneum: Sensitive only to stretch and tearing
Which nerves supply the following:
- Peritoneum lining the ant abdominal wall
- Diaphragmatic peritoneum
- Parietal peritoneum in pelvis
- Visceral peritoneum
Peritoneum lining the ant abdominal wall: T7 -12 and L1
Diaphragmatic peritoneum: Phrenic nerves C3,4,5
Parietal peritoneum in pelvis: Obturator nerve L2,3,4
Visceral peritoneum: Autonomic afferent nerves that supply the viscera
What are the 3 layers of the trilaminar disc? And what does each layer form?
The neural tube and body wall are derived from the ectoderm
The cardiovascular, and musculoskeletal systems, and the body cavities (coeloms) are derived from mesoderm
The gastro-intestinal, respiratory and reproductive tracts are derived from endoderm
What are the stages of GI developement
Day 14: Trilaminar disc formation
Day 17: Notochord burrow from primitive node, between ecto and endoderm, undergoes a series of developmental changes. Becomes a plate that induces the overlying ectoderm to become a neural plate.
The mesoderm cavities to form the coeloms. In the abdomen this intra-embryonic coelom becomes the peritoneal cavity
Day 18: Cephalo-caudal and lateral folding of trilaminar disc. Creates:
- Endodermal tube of pharynx and oesophagus
- Stomach and intestinal tract
- Glands associate with the GI tract
What are the 3 stages of embryonic folding in gut tube formation?
- Endoderm is pinched off to form the gut tube and communicates with yolk sac
- Mesoderm moves to what will become posterior abdominal wall
- Lateral folds close body wall and enclose intra-embryonic coelom
What is exophalos?
Failure of intestine to return to abdomen, lies within peritoneum and amnion in umbilical cord.
What is gastroschisis?
Failure of abdominal wall, contents not covered by peritoneum or amnion
The stomach and proximal part of the duodenum have a ventral mesentery, which becomes….
Lesser omentum and falciform ligament
What is the difference between a rolling and a sliding hernia?
Sliding: The normally intra-abdominal part of the gastro-oesophageal junction has managed to get above the diaphragmatic oesophageal hiatus formed by the left and right crura, but mainly the right crus.
Present with: Heartburn, reflux, dysphagia
Rolling: Part of the fundus of the stomach has herniated through the diaphragm but the gastro-oesophageal junction is still intact and below the diaphragm.
Present with: Dysphagia
- Why is the pain of hiatus hernia worse after eating food?
Food and fluid in the stomach stimulates the release of gastric acid that will then irritate the lower oesophagus and cause increased pain and discomfort – the hiatus hernia disrupts the cardiac sphincter and allows reflux from the stomach into the lower oesophagus.
- If there were intestinal structures in the left hemi-thorax of a neonate what do you think you would find on examination of their respiratory, cardiovascular and gastrointestinal systems?
Briefly, there will be asymmetry in the thoracic examination – loss of resonance and dull to percussion on the side with the intestine instead of the lung (left in this case); the apex beat of the heart may well be shifted to the right because of the pressure created by intestine in the left thorax.
- How could you differentiate between pain from a bleeding duodenal ulcer and someone having a myocardial infarction?
Both will cause a sympathetic response to compensate for the inadequate tissue perfusion, resulting in a tachycardia, and the patient will be pale and sweating. An MI tends to be considerably more painful (central chest radiating down left arm). A DU is often not painful, although there may be a history of epigastric pain. There will be altered blood in the stool – melaena.
- Why is pericardial or diaphragmatic pain referred to the shoulder tip?
Both the diaphragm and the pericardium are supplied by the phrenic nerve – C3, 4, 5. The brain cannot localise visceral pain and thinks it is coming from the skin. The C4 dermatome is over the shoulder tip.
