Week 1/2 - A(1) - Anatomy 1&2 - Mastication, oral cavity, Pharynx, stomach, fore/mid/hindgut, abdo muscles/autonomics, peritoneum

Question 1

Where does jaw opening and closing occur at? What are the muscles that control these movements? What is the nerve supply of these muscles?

Answer 1

Jaw opening and closing occurs at the temperomandibular joint (TMJ) - all supplied by mandibular division of trigeminal nerve (CN V3) Jaw opening - * lateral pterygoid Jaw closing * Masseter * Medial pterygoid * Temporalis

Question 2

Which muscles are felt when you clench your jaw? What is their attachments?

Answer 2

Masseter - attaches from the zygomatic arch to the lateral ramus (external)of the mandible Temporals - attaches from temporal fossa/fascia to coronoid process and anterior border of the ramus of the mandible

Question 3

What is the attachment of the medial and lateral pterygoid muscles? Which opens the jaw again?

Answer 3

Medial pterygoid - angle of mandible (medial side) to pterygoid plates of sphenoid bone Lateral pterygoid - opens jaw - condylar head of mandible to pterygoid plates of sphenoid bone

Question 4

What are the divisions of the trigeminal nerve? What are their foramen? Which are sensory and which provide motor innervation?

Answer 4

CNV1 - Ophthalmic division - superior orbital fissure CN V2 - Maxillary division - foramen rotundum CN V3 - Mandibular division - foramen ovale CN V1&2 are only sensory CNV3 - provides sensory and motor

Question 5

How many adult teeth are there in total? What are the adult teeth? Which are known as the wisdom teeth?

Answer 5

32 adult teeth in total There are upper/lower right and left dental arches Dental arch consists of * Incisors - 1&2 * Canines - 3 * Pre-molars - 4&5 * Molars - 6,7&8 - third molar , tooth 8) is referred to as the wisdom teeth

Question 6

What provides general sensation to the superior (gingiva and palate) and inferior halfs (gingiva and floor) of the oral cavity?

Answer 6

General sensation to the superior half of the oral cavity - maxillary division of CN V General sensation to the inferior half of the oral cavity - mandibular division of CN V

Question 7

What is the protective reflex that prevents foreign bodies from entering the pharynx or larynx? Which nerves govern this reflex? When spraying a local anaesthetic eg for upper endocscope, the sensory action potential in what nerves will be blocked?

Answer 7

Gag reflex - protective reflex * Sensory part or afferent limb - fibres within CN IX (glossopharyngeal) * Motor part of efferent limb - fibres within CN IX and CN X (vagus) - constrict the pharynx Local anaesthetic will block sensory action potentials in * CN V2, V3, VII and IX

Question 8

What innervates the tongue with general sensory and special sensory fibres? What is the special sensation?

Answer 8

Anterior 2/3rds of the tongue General sensory - CN V3 Special sensory - chorda tympani branch of facial nerve Posterior 1/3rd of the tongue General and special sensory - all CN IX

Question 9

What modalities does the facial nerve provide? What is the route of the facial nerve?

Answer 9

CN VII provides general and special sensory, motor and parasympathetics Emerges at the pontomedullary junction - into the temporal bone through the internal acoustic meatus - through temporal bone within the facial canal - exits the temporal bone through the stylomastoid foramen

Question 10

What are the three salivary glands? Where do they secrete? What is the most common tumour of the salivary glands?

Answer 10

Parotid gland - secretes opposite the upper 2nd molar Sublingual gland - secretes under the tongue in the sublingual folds Submandibular gland - floor of mouth via sublingual caruncle Pleomorphic adenomais the most common type of salivary gland tumor

Question 11

What modalities does CN IX carry? What is the course of CN IX?

Answer 11

CNIX carries * general sensory - to posteiror wall of oropharynx and posterior 1/3rd of the tongue * Special sensory to posterior 1/3rd of the tongue * Parasympathetic to the paratoid gland It arises at the medulla and exits the skull through the jugular foramen

Question 12

The extrinsic muscles of the tongue originate outside the tongue and embed into the tongue * What are the four extrinsic muscles? * What is the attachments of the extrinsic muscles of the tongue?

Answer 12

All insert into the tongue Genioglossus arises from superior genial tubercles of the mandible Hyoglossus -arises from the hyoid bone Styloglossus - arises from styloid process of temporal bone Palatoglossus - arises from the palatine aponeurosis of soft and hard palate

Question 13

What is the function of the extrinsic muscles of the tongue? What is the nerve supply?

Answer 13

Palatoglossus Styloglossus Hyoglossus Genioglossus * Function - change the position of the tongue during mastication, swallowing and speech * All innervates by the hypoglossal nerve (CN XII) except palatoglossus which is innervated by CN X

Question 14

What is the function of the intrinsic muscles of the tongue? What are they?

Answer 14

The intrinsic muscles of the tongue modify the shape of the tongue for function. They are named according to the direction in which they travel and originate / insert in the tongue: * Superior longitudinal * Transverse muscles * Vertical muscles * Inferior longitudinal

Question 15

What is the nerve supply to the intrinsic muscles of the tongue? What is the modalities of this nerve? Where does it arise and how does it exit the skull?

Answer 15

The hypoglossal nerve provides motor innervation only It supplies all the intrinsic muscles of the tongue It supplies all the extrinsic muscles of the tongue (except palatoglossus - CN X) It arises at the medulla and exits the skull through the hypoglossal canal

Question 16

What innervates the different regions of the pharynx? What level is the upper oeseophageal sphincter and what is it also known as? Which muscle forms it?

Answer 16

Nasopharynx - CN V2 Oropharynx - CN IX Laryngopharynx - CN X Upper oesophageal sphincter aka cricopharyngeus is at C6 - (pharynx becomes oesopagus) - formed from the lower fibres of the inferior constrictor muscles of the pharynx

Question 17

What muscles are on the inner and external layers of the pharynx? What is the function of the layers of muscles?

Answer 17

Inner layer of pharynx - longitudinal muscles - elevate the pharynx and larynx, contract to shorten the phaynx - Raise the larynx to close over laryngeal inlet during swallowing External layer - constrictor muscles - - contract sequentially to propel food bolus

Question 18

What is the little piece of elastic cartilage that will bend and close the laryngeal inlet when a bolus of food comes into contact with it?

Answer 18

This is the epiglottis

Question 19

What muscle closes the lips to prevent drooling? Does parasympathetic or sympathetic innervation increase peristalsis?

Answer 19

Orbicularis oris prevents drooling (muscle of facial expression CN VII) Paraympathetic innervation increases peristalsis Sympathetic innervation decreases peristalsis

Question 20

Is the lower oeseophageal sphincter a phsyicological or anatomical sphincter? What contributes to the lower oesophageal sphincter? What does the sphincter help to prevent?

Answer 20

Lower oeseophageal sphincter is physiological rather than an anatomical sphincter. Contributing: -Contraction of diaphragm intrabdominal pressure - Slightly higher than intragastric, - oblique angle of which oeseophagus enters the cardia of the stomach Sphincter helps to prevent gastrooeseopeal reflux

Question 21

What level does the oesophagus pass through the diaphragm and with what?

Answer 21

Oesophagus passes through the diaphragm at T10 vertebral level along with the vagus nerve (anterior and posterior vagal trunks)

Question 22

What is the change in mucosa from the oeseophagus to the stomach? What is the type of cancer that can be formed due to reflux from the stomach? (how)

Answer 22

Mucosa change from stratified squamous epithelium of oesophagus to columnar epithelium of stomach Can cause adenocarcinoma to arise * Gastric reflux can cause metaplasia of epithelium in oesophagus from stratified squamous to columnar over time - Barret’s oeseophagus * If this continues, can lead to uncontrolled proliferation - adenocarcinoma

Question 23

What are the four parts of the stomach? What is the small notch on the lesser curvature of the stomach? What is the rugae in the stomach?

Answer 23

Stomach fundus (often gas filled), cardia (opening), body (central portion), pylorus (antrum, canal and sphincter) Small notch is known as the incisura angularis Rugae are the visible folds in the stomach that allow for increased surface area and hence increased absorption

Question 24

Approximately how long is the small intestine? What are the different regions from proximal to distal? What are the different regions of the large intestine?

Answer 24

Small intestine is around 7m long - duodenum, jejunum, ileum Large intestine from - The colon - caecum, appendix, ascending, transverse, descending, sigmoid The rectum The anal canal The anus

Question 25

The abdominal organs can be described in 3 parts depending on their embryological origin \* Foregut \* Midgut \* Hindgut Name the organs in each and where each section starts/ends

Answer 25

Foregut - oeseophagus to mid-duodenum (includes liver, gallbladder, spleen, 1/2 of pancreas) Midgut - mid-duodenum to proximal 2/3rds transverse colon (includes 1/2 of pancreas) Hindgut - distal 1/3rd of transverse colon to proximal 1/2 of anal canal

Question 26

The abdominal cavity can be divided into regions and quadrants What are the 9 regions and what lines divide it?

Answer 26

9 regions Right/left hypochondrium Epigastric Right/left flank/lumbar Umbilical Right/left iliac fossa/inguinal Suprapubic/hypogastric Divided along mid-clavicular line, subcostal and transtuberulcar planes

Question 27

What are the 4 quadrants and what divides them?

Answer 27

Right / left upper quadrant Right/left lower quadrant Divided by median plane and trans-umbilical plane

Question 28

What are the muscles of the anter-lateral abdominal wall?

Answer 28

Rectus abdominus External oblique Internal oblique Transversus abdominus (then the parietal peritoneum)

Question 29

What is the rectus sheath formed by? What does the rectus sheath contain? When does it change from being anterior/posterior?

Answer 29

The rectus sheath is formed by the aponeuroses of the external/internal oblique and transverse abdominal muscles. It contains the rectus abdominis and pyramidalis muscles. Can be divided into anterior and posterior laminae. Below the arcuate line, (1/2 from umbilicus to pubic crest) the rectus sheath is only anterior

Question 30

What are the fibrous tendinous intersections surrounding the semilunaris? What is the fibrous structure that runs down the midline of the abdomen? What is it formed from?

Answer 30

Tendinous intersections of rectus abdominus - - Transverse tendinous intersections - Linea semilunaris - the curved intersection either side of rectus abdominus Linea alba - FIbrous midline structure formed from the aponeurosis of the anterolateral abdominal wall muscles

Question 31

What lines the abdominopelvic cavity and organs? - how would you describe it What are the two parts of it? What is the space between the two parts?

Answer 31

The peritoneum is a thin, transparent, semi-permeable serou membrane that lines the abdominopelvic cavity and organs \* The peritoenum in contact with the body wall (soma) is the parietal peritoenum \* The peritoneum in contact with the organs is the visceral peritoneum \* The space in between this continuous layer of membrane is the peritoneal cavity

Question 32

Organs are classed as ‘intraperitoneal’, ‘retroperitoneal’ or ‘with a mesentery’, depending on their relationship with the peritoneum What is an intraperitoneal organ and give an example? What is a retroperitoneal organ?

Answer 32

Intraperitoneal organs are almost completely enveloped by visceral peritoneum, which covers the organ both anteriorly and posteriorly. Examples include the stomach, liver and spleen. Retroperitoneal organs only have visceral peritoneum on the anterior surface - therefore are retro

Question 33

Give examples of retroperitoneal organs? (mnemonic to help remember is SADPUCKER)

Answer 33

Suprarenal (adrenal) glands Aorta (abdominal) / IVC Duodenum (except part 1) Pancreas (except tail) Ureters Colon (ascending and descending) Kidneys Esophagus Rectum

Question 34

What is a mesentery and how is it formed?

Answer 34

Mesentery is a double layer of peritoneum Formed by the visceral peritoenum wrapping behind the organ to form a double layer - therefore suspending the organ from the posterior abdominal wall - very mobile eg small intestine

Question 35

The mesentery of the small intestine is simply called ‘the mesentery’. Mesentery related to other parts of the gastrointestinal system is named according to the viscera it connects to What is the mesentery connected to the transverse, sigmoid colon and appendix called?

Answer 35

The transverse and sigmoid mesocolons The mesoappendix

Question 36

What is the omentum and what does it do? Where are the lesser and greater omentum found?

Answer 36

The omentum is formed from folds of peritonem connecting the stomach with other organs The omenta divided the peritoneal cavity into a greater and lesser sac The lesser & greater omentum are found at the lesser& greater curvature of the stomach respectively

Question 37

How do the greater and lesser sacs communicate? Where does the portal triad lie? - what is in the portal triad?

Answer 37

The greater and lesser sacs communicate through the omental (epiploic) foramen The portal triad is found in the free edge of the lesser omentum (aka the hepatoduodenal ligament) \* Proper hepatic artery \* Hepatic portal vein \* Common bile duct

Question 38

The peritoneum at its inferior aspect drapes over the superior aspect of the pelvic organs What are the pouches that are formed? What is the most inferior part of the peritoneal cavity when standing in females?

Answer 38

Peritoneum forms pouches when draping over the superior aspect of pevlic organs Males - rectovesical pouch Females - Rectouterine pouch aka pouch of Douglas - most inferior part of abdo cavity in female when standing Vesico-uterine pouch

Question 39

What is it known as when excess fluid collects within the peritoneal cavity as a result of pathology? What can it cause? How s treated?

Answer 39

Excess fluid collecting within the peritoneal cavity is known as ascitic fluid - condition known as ascites Can be treated by drainage - paracentesis (aka abdominocentesis)

Question 40

What must be carefully avoided during paracentesis? Where does this structure arise?

Answer 40

During the procedure, needle must be placed lateral to the rectus sheath to avoid the inferior epigastric artery The inferior epigastric artery arises from the external iliac artery just medial to deep inguinal ring

Question 41

Abdominal pain - 4 main questions arise here \* Location \* Character \* Timing \* Pain referral pattern What do you need to think about for each of these?

Answer 41

Location \* Anatomy that lies there or referred \* Localised (somatic) or generalised (visceral) pain Character \* Localised - sharp and stabbing \* Visceral - dull, achy and nauseating Timing \* Does it come and go (colicky pain) Pain referral pattern \* Showing classical distribution of a specific organ

Question 42

Where do the sympathetic nerves leave the spinal cord to get to the abdominal organs? Where do they synapse? What is the exception?

Answer 42

Sympathetic outflow to the abdominal organs - enter sympathetic chain bilaterally and leave in abdominopelvic splanchnic nerves between T5 and L2 They synapse at prevertebral ganglia except the sympathetic to adrenal gland which synapses essentially on the organ

Question 43

How do the post-sympathetic nerve fibres get from the prevertebral ganglia to the abdominal organs? What spinal cord level does the sympathetics to the adrenal gland arise from and where do they synapse?

Answer 43

Hitch a ride on surface of arterial branches leaving the abdominal aorta Sympathetics for adrenal gland leave spinal cord at T10-L1 to the sympathetic chain --\> abdominopelvic splanchnic nerves, DOES NOT synapse, is carried with the periarterial plexuses to synapse directly at the adrenal cells

Question 44

What nerves carry parasympathetics to the abdominal organs?

Answer 44

Vagus nerve (CN X) - from oeseophagus to proximal 2/3rds of the transverse colon Pelvic splanchnic nerves - distal 2/3rds of transverse colon to the proximal 1/2 of anal canal

Question 45

How do the parasympathetics from the vagus nerve reach the organs?

Answer 45

Vagus nerve presynaptic parasympathetic fibres enter abdominal cavity on surface of oesopagus and travel into periarterial plexuses around the aorta Carried to walls of organs where they synapse on ganglia

Question 46

Where do visceral afferent (sensory) fibres travel to spinal cord from \* Foregut structures \* Midgut structures \* Hindgut structures Where does pain tend to be felt from these structures?

Answer 46

Foregut structures - T6 to T9 - pain tends to be felt in epigastric region Midgut structures - T8-T12 - pain tend to be felt in umbilical region Hindgut structures - T10-L2 - pain tends to be felt in the suprapubic region

Question 47

The somatic motor, somatic sensory and sympathetic nerve fibres supplying the structures of the abdominal part of the “body wall” travel within which nerves?

Answer 47

The thoracoabdominal nerves - 7th to 11th intercostal nerve Subcostal nerve (T12 anterior rami aka 12th intercostal nerve) L1 anterior rami \* Iliohypogastric \* Ilioinguinal