Anatomy Flashcards
In which area of the body is the anus found?
Perineum
In which area of the body is the rectum and anal canal found?
Pelvis
Which GI organ is found in the chest?
Oesophagus
What is the scientific word for swallow?
Deglutition
What i the scientific word for chewing?
Mastication
What are the 4 functions of the upper GI tract?
Mastication, deglutition, taste and salivation
What is the Buccinator muscle and what is its function?
Cheek muscle which is used for facial expression and pushing lateral food bollus’
What is the nerve supply to the buccinator muscle?
CN VII (facial nerve)
How many teeth in the normal adult?
32- 16 on the mandibular dental arch and 16 on the maxillary dental arch
What type of teeth are: 1 and 2? 3? 4 and 5? 6, 7 and 8?
1 and 2 are incisors
3 is canine
4 and 5 are premolars
6, 7 and 8 are molars teeth
Which teeth are your wisdom teeth?
8
What is the head of the condylar process and where does it sit when the mouth is closed?
Head of the the mandible and sits in the mandibular fossa of the temporal bone, posterior to the articular tubercle
What is the zygomatic arch?
The extension of the temporal bone to meet the zygoma and contains the articular tubicle
What are the 3 muscles used to close the mouth?
Temporalis muscle, Masseter muscle (strongest) and the medial pterygoid muscle
What muscle is used to open the mouth?
Lateral pterygiod
What is the innervation of the 4 muscles of mastication?
Mandibular devion of the trigeminal nerve. CN V3
What in the origin and insertion of the temporalis muscle?
Origin = Coronoid process of the mandible Insertion = the temporal fossa
What is the origin and insertion of the masseter muscle?
Origin = angle of the mandable Insertion = zygomatic arch
What is the origin and insertion of the medial pterigiod muscle?
Origin = angle of the mandable (medial side) Insertion = pterigiod plates of the sphenoid bone
What is the origin and insertion of the lateral pterigiod muscle?
Origin = Condyle of mandible Insertion = pterigiod plates of the sphenoid bone
Which branch of the trigeminal nerve has motor innervation?
CN V3
What are the 2 cavities of the TMJ and what are there functions?
Superior cavity for translation and inferior cavity for rotation.
Translation moves the condyler process of the mandable onto the articular tubicle of the temporal bone to allow for more rotation
What separates the 2 cavities of the TMJ?
Articular disc
What is the course of CN V3 (mandibular devision of the trigeminal nerve?
From pons and exits the skull through the foraman ovale to to muscles of mastication and sensory area
What types of nerve are in CN V3?
Motor and sensory
Bone in the body that does not articulate with any other bone?
Hyoid bone
Which tonsils are commonly removed?
Palatine tonsils
What part of the oral cavity is effected in gum disease?
Gingiva
What may cause the uvula to hang off centre?
Lesions of the vagal nerve
What separates the anterior 2/3rds and the posterior 1/3rd of the tongue?
Sulcus terminus
What is the function of the vertical part of the tongue and what is the innervation for these functions?
Taste and general sensation
CN IX glossopharangeal nerve
What is the function of the horizontal part of the tongue and what is the innervation for these functions?
Taste- CN XII (facial nerve)
General sensation- CN V3 (mandibular brach of the trigeminal nerve)
What are the papillae with taste buds? (3)
Foliate papillae
Vallate papillae
Fungiform papillae
What are papillae?
NOT taste buds but may contain tastebuds. Invaginations on the tongue
Which papillae are for general sensation of temperature and touch ect?
Filiform papilae
What is the course of the facial nerve (CN XII)?
From the pontomedullary junction through the temporal bone via the internal acoustic meatus to the stylomastiod foramen
What does the facial nerve supley?
Horizontal aspect of the tongue (taste)
Muscles of facial expression
Glands in the floor of the mouth
What nerve fibres does the facial nerve contain?
Special sensory, sensory, motor and parasympathetic
What is the general sensory innervation for the superior and inferior half of the oral cavity?
Superior half is CN V2
Inferior half is CN V3
Can people have a gag reflex when unconscious?
No
Spraying a local anasthetic in the mouth will block sensory action potentials in which nerves?
CN V2, V3, VII and IX
Used in endoscopy
Which nerve fibre carries the sensory part of the gag reflex?
CN IX glassopharageal
Which nerve fibre carries the motor part of the gag reflex?
CN IX and X
Mostly vagus
What is the course of CN V2 (maxillary devision of the trigeminal nerve)?
From the pons through the foraman rotundum (traveling anteriorly) to the sensory area of the mid face
What type of nerve fibres are found in CN V2?
Sensory ONLY
What is the course of CN IX (glossopharangeal nerve)?
From the medulla through the jugular foramen to the posterior wall of the oropharynx, parotid gland and vertical aspect of the tongue.
Which cranial nerves exit the brain through jugular foramen?
CN 9, 10 and 11
What are the 3 salivary glands?
Parotid gland
Submandibular gland
Sublingual gland
Where does the parotid gland secrete into the mouth?
Upper second molar (upper 7)
Where does the submandibular gland secrete into the mouth?
Lingual caruncle
Where does the sublingual gland secrete into the mouth?
Floor of the mouth
Which cranial nerve innervates the parotid gland?
CN IX
Which cranial nerve innervates the submandibular and sublingual gland?
CN VII
What are the 4 pairs of extrinsic muscles of the tongue?
Palatoglossus, Styloglossus
Genioglossus
Hyoglossus
Which CN innervates the muscles of the tongue?
All tongue muscles are innervated by CN XII (hypoglossal nerve) exept the palatoglossus which is the vagus
What is the function of extrinsic muscle of the tongue?
Change the position of the tongue during masstication, swallowing and speech
What is the function of the intrinsic muscles of the tongue?
Modify the shape of the tongue during function
How many pairs of intrinsic muscles of the tongue?
4
What is the course of the Hypoglossal nerve?
From the medullas through the hypoglossal canal to the muscles of the tongue
What nerve fibres are contained in the hypoglossal nerve?
Motor ONLY
How many musclesare in the pharynx?
3 Circular constrictor muscles and 3 Longitudinal muscles
What are the names f the 3 circular muscles of the pharnx and which CN innervates them?
Superior, middle and inferiorconstrictor muscles all innervated by the vagus nerve
At what vertebral level is theupper oesophageal sphincter?
C6 cricopharyngeus (levelof the cricoid cartilage)
Where do all the constrictor muscles of the pharynx insert?
The midline raphe
What is the function of the muscles in the pharynx?
To elevate the pharynx and the larynx. to attach to the larynx and shorten the pharynx when contracting to raise the larynx to close over the laryngeal inlet.
Which nerves supply the longitudinal muscles of the pharynx?
CN X and IX
All the muscles involved in swallowing are skeletal/smooth muscles and the initiation of swallowing is voluntary/involuntary?
Skeletal
Voluntary
What normal ‘constrictionsof the oesophagusmay be seen with a barium swallow?
Diaphramatic constriction
Upper oesophageal sphinctre
Arch of the aorta
Left main bronchus
Where does the oesophagus start and end?
Starts at the inferior edge of the cricopharyngeus muscle (C6)
Ends by entering the cardia of the stomach
When no food is present are the walls of the oesophagus open or closed?
Closed
2 sphincters in the oesophagus. Which is anatomical and which is physiological and why?
Attomical is the upper oesophageal sphincter as it has full circular muscle around it.
Physiological is the the lower oesophageal sphincter as it closes due to external factors
Where is the oesophageal plexus found and what are the nerve fibres within it?
Surface of the oesophagus to supply the smooth muscle within its walls. Contains parasympathetics (vagus) and sympathetics which influence the ENS
What can dilation of the LA cause with reference to the GI tract?
Dysphagia as the oesophagus passes posterior to the surface of the heart (LA)
What 3 factors produce the sphincter effect at the LOS?
1) Contraction of the diaphragm
2) Intraabdominal pressure slightly higher than intragastric pressure
3) Oblique angle that the oesophagus enters the cardia of the stomach
What can lead to symptoms of reflux
Hiatus hernia either paraoesophageal hiatus hernia or sliding hiatus hernia
What is the Z line in the oesophagus?
Abrupt change in the type of mucosal lining in the oesophageal wall (pink to red) LOS lies superior to this.
What are the 5 anatomical areas of the stomch?
Cardia, Fundus,Body, Antrum and pylorus
Where does the stomach lie on surface anatomy?
Mainly in the left hypocondrium, epigastic and umbilical regions
What are rugae?
Folsing in the stomach which allow for increased expansion of the stomach. Can disappear in obese individuals
What are the anatomical relations of the stomach?
Anterior Lesser and greater omentum, Liver, gall bladder and transverse colon Superior Left hemi diaphragm Posterior Splenic vessels, spleen and pancreas
What are the risks of a posterior stomach ulcer?
Damage to the spleen and pancreas
Haemorrhage of the spleenic vessels
What makes up the small intestine?
Duodenum, jujunum and illeum
What makes up the large intestine?
Caecum, Appendix, Ascending, transverse and descending colon, sigmoid colon, rectum, anal canal and anus
What is the foregut and what is the vessel and nerve supply?
Oesophagus- mid duodenum, liver, gall bladder, spleen and 1/2 pancreas
Caelliac artery and caelliac ganglion
What is the midgut and what is the vessel and nerve supply?
Mid duodenum- proximal 2/3rds of transverse colon and 1/2 pancreas.
Superior mesenteric artery and superior mesenteric ganglion
What is the hindgut and what is the vessel and nerve supply?
Distal 1/3rd of the transverse colon to the proximal 1/2 of anal canal
Inferior mesenteric artery and inferior mesenteric ganglion
What are the 9 superficial regions of the abdomen?
Left and right hypocondrium and epigastric
Left and right lumbar and umbilical
Left and right inguinal and pubic
Which planes divide up the superficial regions of the abdomen?
Mid clavicular planes
Subcostal plane and transtubercular plane
What is the muscle orientation of the external internal and transverse oblique?
The orientation of muscles is important for making surgical incisions
External = hands in pockets Internal = hands on chest Transverse = horizontal
What is guarding of the abdomen?
Contraction of abdominal and oblique muscles to guard the abdominal organs when injury threatens. Organs are irritating the peritoneum. This also occurs in peritonitis
What is the peritoneum?
A thin, transparent, semi-permiable, serous membrane. It lines the walls of the abdominopelvic cavity and organs.
The peritoneum is a continuous membrane. T of F?
True
Parietal on the body wall and visceral engulfing organs
What does the peritoneum secrete and why?
Lubricating fluid as the gut moves a lot
Is the peritoneal cavity enclosed in males and females?
Enclosed in males
Uterine tubes in the females mean it is not fully enclosed meaning UTIs can spread into the peritoneal cavity.
What can cause peritonitis?
Blood, pus or faeces in the peritoneal cavity will cause severe and painful inflammation. Infection and cancer can easily spread throughout the cavity
What is a intraperitoneal organ and give examples?
Almost completely covered in visceral peritoneum- minimally mobile.
Eg Stomach, liver, gall bladder, spleen, parts of the small intestine, transverse colon.
What are organs with a mesentary (intraperitoneal) and give examples?
Covered in visceral peritoneum and the visceral peritoneum wraps behind an organ to form a double layer- mesentary- which suspends the organ from the posterior abdominal wall (parietal peritoneum). Very mobile
Eg small intestine
What is a retroperitoneal organ and give examples?
Only has visceral peritoneum on its anterior surface and is localed in the retroperitoneum. Limited mobility and held in place.
Eg Kidneys, adrenal gland, pancreas, ascending colon and descending colon
Which system is the spleen part of?
Lymphatics- NOT GI
How des the peritoneum form?
Secondary to the growth and formation of the GI ract duing embryology. Similar to the pericardium. The GI tract grows out into the umbilicus of the baby during development as its too big and then receeds as the baby grows
What are the 3 types of peritoneal formations?
1) Mesentry- usually connects organs to posterior body wall
2) Omentum (greater and lesser)- double layer of peritoneum which passes from the liver/stomach to adjacent organs
3) Peritoneal ligaments- double layer of peritoneum connecting organs to each other or the body wall
What is within the mesentery?
Blood and lymph vessels, nerve, lymph nodes and fat
What are the 3 types of mesentery?
1) Mesentry proper (small intestine)
2) Transverse and sigmoid mesocolon
3) Mesoappendix
Describe the greater omentum
4 layered structure. Has a greater sac (anterior to stomach and all of intestine) and lesser sac (posterior to stomach). Hangs like an apron and attaches the greater curvature of the stomach to the transverse colon.
Describe the lesser omentum
Double layered structure wich attaches the lesser curvature of the stomach/duodenum to the liver. It has a free edge on the right.
Why is the free edge of the lesser omentum important?
Contains the portal triad (hepatic portal vein, hepatic artery proper and the common bile duct) and can be used in surgery to stem the blood supply to the liver
What makes the free edge and fixed edge of the lesser omentum?
Free edge = Hepatoduodenal ligament
Fixed edge = Hepatogastric ligament
How do the greater and lesser sacs of the omentum communicate?
Through the omenttal foramen (foramen of winslow)
What are the 4 peritoneal ligaments?
Splenorenal ligament
Gastosplenic ligament
Hapatogastic ligament
Hepatoduodenal ligament
What is the peritoneal pouch found in the male?
Rectovesical pouch
What are the peritoneal pouches found in the female?
Vesico-uterine pouch and recto-uterine pouch (pouch of douglas )
What is ascites?
Collection of fluid in the peritoneal cavity
What are the most common causes of ascites?
Cirrhosis and portal hypertension (liver)
How can ascitic fluid be drained?
Paracentesis (abdominocentesis)
Ultrasound guidance is recommended to check its fluid!
Where should the needle be placed in abdominocentesis?
Lateral to the rectus sheath avoiding th inferior epigastric artery.
Where does the inferior epigastric artery come from and what is its course?
Branch of the external illeac artery (medial to the deep inguinal ring) and ascends in anterior abdominal wall deep to the rectus abdominus
If there is a hernia medial to the inferior epigastric artery is it direct or indirect?
Direct
Indirect if the hernia is lateral to the artery
4 questions about abdominal pain?
1) Location? is it localised?
2) Character? Somatic pain is sharp whereas visceral pain is dull
3) Timing? Colicky pain due to peristalsis
4) Pain referral pattern?
Which nerves supply the organs and visceral peritoneum within the abdominal cavity?
Visceral afferents (ENS) and piggy back sympathetics. Autonomic nervous system (influences the ENS) including sympathetics and parasympathetics
Which nerves supply the abdominal wall from the skin to the parietal peritoneum?
Somatic sensory and motor nerves and sympathetic nerve fibres
How do sympathetic nerve fibres get from the CNS to abdominal organs?
Clue: Short pre ganglionic neurone, long post ganglionic neurone
1) Leave the spinal cord between levels T5 and L2
2) Enter the sympathetic chains but do NOT synapse
3) Leave sympathetic chain within abdominopelvic splanchnic nerves
4) Synapse at prevertebral ganglia
5) Postsynaptic fibres pass from the ganglia onto the surface of the arterial branches leaving the abdominal aorta
6) Take part in the periarterial plexues with other nerve fibres
Where are the pre vertebral ganglia found?
Anterior to the aorta at the exit points of major branches of the abdominal aorta
How do sympathetic nerve fibres get from the CNS to the adrenal gland?
1) Leave the spinal cord at T10-L1
2) Enter the abdominopelvic splanchnic nerves
3) Do NOT synapse at prevertebral ganglia
4) Carried with periarterial plexuses to the adrenal gland
5) Synapse directly onto cells.
How do parasympathetic nerve fibre get from the CNS to fore and mid gut?
Vagus nerve
1) presynaptic parasymapthetic neurones enter the abdominal cavity on the surface of the oesophagus
2) Travel into the periarterial plexus around the abdominal aorta
3) Carried to the walls of the organs where they synapse in ganglia
How do parasympathetic nerve fibres get from the CNS to the hing gut?
Pelvic splanchnic nerves (S2, 3, 4)
1) Presynaptic parasympathetic nerve fibres supply the smooth muscle and glands of the descending colon to the anal canal
Which superficial region is pain from the foregut organs felt in and why?
Epigastric
Visceral afferent nerve fibres from foregut structures enter the spinal cord at T6-T9
Which superficial region is pain from the midgut organs felt in?
Umbilical
Visceral afferent nerve fibres from midgut structures enter the spinal cord at T8-T12
Which superficial region is pain from the hindgut organs felt in?
Pubic
Visceral afferent nerve fibres from hindgut structures enter the spinal cord at T10-L2
Why is abdominal pain referred?
Pain fibres from most abdominal organs run alongside sympathetic fibres back to the spinal cord and pain from these organs tends to be perceived in the dermatomes of the levels at which they enter the spinal cord
What are the body wall nerves supplying the abdomen and what fibres to they contain?
Thoracoabdominal nerves T7-T11
Subcostal nerve T12
Iliohypogastric nerve- half of L1 anterior ramus
Ilionguinal nerve- half of L1 anterior ramus
Why are the thoracoabdominal nerves so named?
Which muscle layers to they travel between?
There are intercostal nerves which travel anteriorly and leave the intercostal space
Travel between the internal oblique and the transverse abdominus.
Why does pain from appendicitis begin as dull and achy pain in the umbilicus and become sharp in the right illieac fossa
Appendix is a mid gut organ- so as the appendix inflames it irritates the visceral peritoneum which is felt in the umbilicus region as it enters the spinal cord at T8-T12. As the appendix becomes more inflamed it irritates the parietal peritoneum in the right iliac fossa which is a body wall structure and is felt as a sharp localised pain
What is jaundice?
Yellowing of the sclera (white of the eyes) and skin
WHat causes jaundice?
Increase in the blood levels of billirubin
Which organs are involved in the production of billirubin and bile?
Liver, Spleen, pancreas, gallbladder and small intestine
What is bilirubin?
Normal byproduct of the breakdown of red blood cells
Where does the breakdown of RBC normally occur?
Spleen
Where does bile enter the duodenum?
2nd part of the duodenum
What is bilirubin used to form?
Bile in the liver
Why is bile important?
For the normal absorption of fats from the small intestine and the nutralisation of chyme
What are the functions of the liver?
Glycogen storage, bile secretion and other metabolic functions
Where is the liver located? (surface anatomy)
Right upper quadrant
Right hypochondrium and epigastric regions
Why does the location of the liver change on breathing?
Because it is attached to the inferior surface of the diaphragm and moves with the diaphragm.
Which ribs protect the liver?
Ribs 7-11
What are the anatomical relations of the liver?
Superiorly = right hemidiaphragm Posterior and inferior = Gall bladder Inferior = hepatic flacture of colon Posterior = Right kidney, right adrenal gland, IVC and abdominal aorta Posterior at the left side = stomach
What are the 4 anatomical lobes of the liver?
Left lobe
Right lobe
Caudate lobe (looks like a tail and flicks under IVC but is superior)
Quadrate lobe
What is the porta hepatis?
Site for entrance of portal triad structures
Which ligament separates the right and left lobes of the liver?
Falciform ligament- structure of the peritoneum
Whatis the round ligament of the liver?
Remnant of the umbilical vein
Is the IVC attached to the liver?
Not normally although the liver can grow around the IVC
How many functional segments of the liver?
8
Which anatomical lobe is also a functional lobe?
Quadrate lobe is functional lobe 1
What does each segment of the liver have?
Its own Branch of the hepatic artery Branch of the hepatic portal vein Bile drainage into the bile duct Venous drainage into the IVC
Why is increased central venous pressure directed to the liver?
Because the IVC and hepatic veins lack valves
Do hepatic veins contain oxygenated or deoxygenated blood?
Deoxygenated blood
Where is the portal triad found?
Within the hepatoduodenal ligament
What is within the portal triad?
Hepatic portal vein Hepatic artery (medial) Bile duct (lateral)
What is the first midline branch of the abdominal aorta?
Coeliac trunk
Where is the coeliac trunk in relation the to the peritoneum?
Reteroperitoneal
At what vertebral level does the coeliac trunk leave the aorta?
T12
What does the coeliac trunk supply?
Fore gut
What are the branches of the coeliac trunk?
Splenic artery (posterior to the stomach)
Left gastric artery
Common hepatic artery
What are the branches of the common hepatic artery?
Hepatic artery proper and the gastroduodenal artery
What provides the anastamosis of the foregut and midgut vasculature?
Superior pancreaticoduodenal artery
Why does the splenic artery have a torturous course?
Superior boarder of the pancreas
Where is the spleen in relation to the peritoneum?
Intraperitoneal
Where is the spleen on surface anatomy?
POSTERIOR aspect of Left hypochondrium
Which ribs protect the spleen?
ribs 9-11
What are the anatomical relations of the spleen?
Posterior/superior= diaphragm Anterior = stomach Inferior = splenic flecture Medial = left kidney
What is the function of the spleen?
Break down RBC to produce bilirubin and immune role
Does the spleen move with respiration?
Yes- anatomically related to diaphragm
How is the spleen palpated?
Patient takes deep breath in. Push the spleen up from the back of patient and push upwards o the front
What is the major blood supply to the stomach?
1) Right and left gastric arteries along junction of lesser curvature and lesser omentum (anastamose)
2) Right and Left gastro-omental arteries along greater curvature and greater omentum (anastamose)
What is the minor blood supply to the stomach?
Posterior gastric arteries (from splenic arteries)
Short gastric arteries (from splenic arteries
Where does the left gastric artery branch from?
coeliac trunk
Where does the right gastric artery branch from?
Hepatic artery proper
Where does the Left gastro-omental artery branch from?
Splenic proper
Where does the Right gastro-omental artery branch from?
Gastero duodenal artery
What is the blood supply to the liver?
Hepatic artery proper which divides into the left and right hepatic arteries (oxygenated blood)
Hepatic portal vein (nutrient rich blood)
What proportion of blood to the liver come from hepatic arteries?
20-25%
Is the blood in the hepatic portal vein oxygenated or deoxygenated?
Mostly oxygenated despite going around the GI tract. This is supplemented by hepatic arteries
What shape is a liver lobule?
hexagonal- loss of this shape => pathology
What is at the centre and each cornor of a liver lobule?
Centre = central vein which drains into the hepatic veins and then IVC Corner = interlobular portal triad with a branch of the hepatic portal vein, hepatic artery and billary duct
How many hepatic vein join the IVC?
3
What are the 2 peritoneal cavities related to the liver?
Are they in the greater or lesser sac?
Hepatorenal recess
Subphrenic recess
Greater sac
Where is the lowest part of the peritoneal cavity when supine and therefore where fluid collects?
Hepatorenal recess
Where does the hepatic portal vein drain blood from?
Foregut, midgut and hindgut
Which 2 veins form the hepatic portal vein?
Splenic vein (drains the foregut) Superior mesenteric vein (drains the mid gut)
Where does the inferior mesenteric vein, which drains the hind gut, drain blood into?
60% splenic vein
40% superior mesenteric vein
What are the portal triad structures from anterior to posterior?
Bile duct -anterior
Hepatic artery proper
Hepatic portal vein- posterior
Where does the gall bladder lie in relation to the duodenum?
Anterior to the duodenum
What is the function of the gallbladder?
Stores and concentrates bile in between meals
What are the parts of the gallbladder?
Fundus, body and neck
Which ducts join to form the common bile duct?
Cyctic duct (gallbladder) Common hepatic duct (from liver)
There are sphincres in the common bile duct which are closed between meals. What does this lead to?
The liver is producing bile continuously and when the sphincters are closed the bile backs up and gets pushed into the gallbladder for storage
How does bile flow in and out of the gallbladder?
Cystic duct
What is the valve in the cystic duct?
Spiral valve- glaa stone narrowing
What is the blood supply to the gallbladder?
Cystic artery- branch of the right hepatic artery
What are the sides of the triangle of Calot?
Inferior boarder of the liver
Common hepatic duct
Cystic duct
What is always found in the triangle of calot?
Cystic artery
What is the venous drainage of the gallbladder?
Where the gallbladder adheres to the liver there are lots of little veins which pass into the liver and the blood is cleaned and enters the IVC through hepatic veins
What causes gall bladder pain?
Irritation from gallstones
Where is gall bladder pain felt?
Foregut organ- pain in epigastric region (visceral afferent T6-T9)
If gall badder irritates anterior of diaphragm where will pain be felt?
Right hypochondrum with referral to the right shoulder (C3, 4, 5)
What is the surgical removal of the gallbladder called?
Cholecystectomy
What is requires for a cholecystectomy?
Identification of the cystic duct and cystic artery.
Variation can occur in both structures
Where does the break down of RBCs usually occur?
Spleen
What is Bilirubin used for?
Formation of bile in the liver
What are the 4 named billary vessels?
Left hepatic duct (drains the left lobe)
Right hepatic duct (drains the right lobe)
Common hepatic duct (when the left and right hepatic ducts unite.
Common bile duct (when the common hepatic duct joins with the cystic duct. Within the portal triad)
What are the 4 parts of the duodenum?
1) Superior (intraperitoneal) with the duodenal cap
2) Descending (retro peritoneal)
3) Horizontal (retroperitoneal)
4) Ascending (retroperitoneal)
Where does the duodenum begin and end?
Begins at pyloric sphincter
Ends at the duodenojejunal flexure
What is the duodenal cap?
An outpouching on the superior part of duodenum which is mobile
WHat is the duodenojejunal flexture?
Small functional sphincter
When does the intestine become intraperitoneal again after the deuodenum?
duodenaojejunal flexure
Which 2 peptide hormones are secreted by the duodenum?
Gastrin and CCK (cholycystokinin)
Enter the blood stream
What is the function of CCK released by the duodenum?
Gall bladder contraction and relaxation of the billary sphincters
Where does pain from a duodenal ulcer present?
Epigastric region because although it’s a modly mid gut organ its very high up
Where is the duodenum in relation to the pancreas?
The duodenum curves around the head of the pancreas. Pancreas in the C shape curve of duodenum. Therefore enlargement of the pancreas can effect the duodenum
Is the pancreas intra or retro peritoneal?
Retroperitoneal
What are the 4 parts of the pancreas?
Head (with uncinate process)
Neck
Body
Tail
Where is the tail of the pancreas found?
In the hylum of the spleen
How does the pancreas develop?
Develops in 2 parts from the duodenum. It develops intraperitoneal and becomes retroperitoneal therefore it is secondarily retroperitoneal
What are the posterior anatomical relations of the pancreas?
Right kidney and adrenal gland, IVC, Bile duct, Abdominal aorta, Superior mesenteric vessels
Left kidgey and adrenal gland, part of the portal venous system
What are the anterior, lateral and superoposterior anatomical relations of the pancreas?
Anterior = stomch Lateral = duodenum Superoposterior = Splenic vessels
Posterior stomch ulcers can effect the splenic vessels and pancreas. T or F?
True
Is the spleen intra or retroperitoneal?
Reteroperitoneal
What are the functions of the pancreas?
Exocrine (acinar cells)- digestive enzymes
Lipase, amylase, protease (trypsinogen, chymotrypsinogen, procarboxypeptidase A and B)
Endocrine (islets of langerhans) Insulin, glucagon and somatostatin.
Where do pancreatic enzymes drain to?
Main pancreatic duct (tail to head) Drains into the Common bile duct
Accessory pancreatic duct (head)
Drains directly into the minor duodenal papilla in the descending duodenum
WHat is the nerve supply to the pancreas?
Vagus = parasympathetic
Abdomino pelvic splanchnic = sympathetic
Coeliac and superior mesenteric ganglia.
Sympathetic and parasympathetic form a periarterial plexus on the pancreas
What is the course of the common bile duct around the duodenuma dn pancreas?
Descends posterioly to the superior part of the duodenum
Travels into a grove on the posterior aspect of the pancreas and joins with the main pancreatic duct forming the Hepatopancreatic ampulla (Ampulla of Vater) (bulge)
Both then drain into the descending duodenum at the major duodenal papilla
What is the hepatopancreatic ampulla?
The bulge at the joining of the common bile duct and main pancreatic duct
What are the 3 anatomical sphincters in the billary system?
Bile duct sphincter and ancreatic duct sphincter just above the hepatopancreatic ampulla in both cases (allow change in concentration of bile and pancreatic enzymes entering the duodenum.
Sphincer of Oddi- controls the entry pf bile and pancreatic enzymes into the duodenum at the major duodenal papilla.
What is a ERCP (Endoscopic Retrograde Cholangiopancreatography) and how is it carried out?
Investigation used to study the bilary tree and pancreas and treat some pathogies within it.
Endoscop is inserted through mouth into duodenum and a cannula is placed in the major duodenal papilla ad radioopaque dye injected back into the bilary tree. Images are then taken
What are the 2 main extra hepatic causes of jaundice associated with the bilary tree
1) Gall stones
2) Carcinoma of the head of the pancreas
Both block the bile duct at variable points causing back up of bile and possibly pancreatic enzymes to the liver.
What happens when bile backs up to the liver?
Overspill’s into the blood and this causes jaundice
WHat is the course of the cystic duct?
Spiral course
What happens if pancreatic enzymes are backed up?
Leak out into the blood or abdomen and digest stuff leading to pancreatisits
What is the intrahepatic causes of jaundice?
Liver failure (cause is directly related to the liver)
What is the blood supply to the duodenum and pancreas?
Superior pancreatoduodenal artery
Inferior pancreatoduodenal artery
These anastamose in the head of the pancreas.
Dorsal pancreatic ateries also supply body and tail of pancreas
Where does the superior pancreatoduodenal artery come from?
Coeliac trunk
common hepatic artery Gastroduodenal artery
Where does the inferior pancreatoduodenal artery come from?
Superior mesenteric artery
Where so the dorsal pancreatic arteries come from?
Coeliac trunk
Splenic artery
At what level does the superio mesenteric artery leave the aorta?
L1
Why is the superior duodenum and pancreas foregut and the inferior parts mid gut?
The anastamosis of superior and inferior pancreatoduodenal arteries
What can cause pancreatic pain?
Pancreatists
What is one cause of pancreatisis?
Blockage of the hepatopancreatic ampulla with a gallstone and bile is diverted to pancreas leading to irritation and inflammation
Where does pain from the pancreas present?
Epigastric or umbilical regions as its foregut and midgut. It can also radiate to the centre of the back at level T10 ish
In advanced cases of pancreatisis, vascular haemorrhage can occur. Where does this occur and why?
Blood fluid will accumulate in the retroperitoneal spaces. Pancreas=tic enzymes can digest blood vessels etc
What is Grey-Turner’s sign?
Purple bleeding in right or left flanks
What is Cullens sign?
Purple haemorrhage around the umbilicus via the falciform ligament
Where does the ejunum begin and the illeum end?
Jejunum begins at the duodenaljujunal flexure
Illeum ends at the illeocaecal junction where there is a valve
Is the transition between jejunum and illeum obvious?
No- it transitions slowly over a distance of the small intestine
What is the function of the ileocaecal valve?
Stop back flow of faecal material
What are the differences between the jejunum and ileum in:
a) Colour
b) wall
c) vascularity
d) mesenteric fat
e) circular folds
f) lymphoid tissue
a) Colour = J is more red than I
b) wall = J is thicker and heavier than I
c) vascularity = J is more vascular than I
d) mesenteric fat = I has more than J
e) circular folds = J has large tall and closely packed folds, I has low and sparse folds
f) lymphoid tissue = I has peyer’s patches
What is a Plicae Circularis?
Circular fold
What is the blood supply to the Jejunum and Ileum?
Superior mesenteric artery via jejunal ad ileal arteries
What is the venous drainage for the jejunum and ileum?
Jejunal and ileal veins into the superior mesenteric vein and then the hepatic portal vein
Which food groups are absorbed in the small intestine and tacked to the portal venous system to the liver?
Proteins and carbohydrates
Where are the vessels for the jejunum and ileum found?
Withinthe mesentary
What is the course of the superior mesenteric artery?
Levels aorta at L1
Travels posterior to the neck of the pancreas
Travels inferiorly, anterior to the uncinate process ot the pancreas and duodenum to enfter the mesentary proper
What is the function of bile?
Neutralise chyme and emulsify fat to allow then to be absorbed into intestinal cells
Do fats enter the portal system?
No
How do absorbed fats enter the systemic circulation?
Fats within chylomicrons are absorbed from intestinal cells into specialised lymphatics of the small intestine- lacteals.
They travel in the lymphatics and enter the circulation at the left venous angle via the horacic duct
Where are the juxta ileal lymph nodes found and where do they converge?
Ileum and converge on the superior mesenteric artery
Lymph vessels tend to lie alongside arteries. What are the main groups of lymph nodes draining abdominal organs?
Coeliac (foregut organs) Superior mesenteric (midgut organs) Inferior mesenteric (hind gut organs) Lumbar (kidneys, posterior abdominal wall, pelvis and lower limbs)
What forms the venous angle?
Junction between the subclavian vein and the internal jugular veins
What are the parts of the colon?
Caecum, Appendix, Ascending, Transverse adn descending colon, sigmoid colon
What are the functions of the large intestine?
1) Defence- they have commensal bacteria
2) Absorption of water and electrolytes
3) Excretion of formed stool
Why are the ascending and descending colon secondarily retroperitoneal?
Because their initial development was intraperitoneal and they became retroperitoneal.
Which parts of the colon have a mesentry and are therefore movile?
Appendix and caecum (little mesentry)
Sigmoid colon
Transverse colon
Why is it important that some parts of teh colon are retroperitoneal?
You don’t want all the contents to be moving around in the abdominal cavity
Where are the paracolic gutters?
2 paracolic gutters (Left and right) Between the lateral edge of the ascending and descending colon and the abdominal wall?
What are the paracolic gutters and what is there function?
Part of the greater sac of the peritoneal cavilty.
Site for collection of pus and fluid in the abdomen (similar to subphrenic and hepatorenal recesses
What are teh 3 features of the colon which distinguish it from the rest of the Intestine?
1) Omental appendices
2) Teniae coli
3) Haustra
What are omental appendices?
Small fatty projections. With a lympoid function. Not found in the small intestine or rectum
What are Teniae coli?
3 distinct longitudianl bands of thickened smooth muscle running form caecum to distal end of sigmoid colon. Orgigionate
at the appendix and converge on the rectum to form continuous smooth muscle. Help to form the haustra
What are haustra?
Bumps on the transverse colon formed by tonic contraction of the teniae coli
Is it normal to see air in the colon and mottled faeces in the rectum?
Yes, especially when no contrast is used
Where would you find the caecum and appendix?
Right iliac fossa.
What is the most common position of the appendix?
Retrocaecal.
The variations mean that patients can present differently with appendicitis.
Where does the appendix attach to the caecum?
Appendiceal orifice on the posterior medial wall of the caecum.
What is McBurney’s point?
Point above the appendiceal orifice.
Line between ASIS and umbilicus. 1/3rd of the way along the line.
Where maximum tenderness is felt in appendicitis.
What is the function of the ileocaecal valve and orifice?
To prevent back frlow of stool into thesmall intestine. Moderately good at this due to small amount of smooth muscle in the valve.
Why does apendicitus pain reduce when lieing in the foetal position?
Because it relaxes the muscles around the appendix
Where is the sigmoid colon found?
Left iliac fossa with a long mesentry (sigmoid mesocolon)
What are the benefits and issues with the sigmoid mesocolon?
+ Lots of movement
- At risk of twisting around on itself
What is Sigmoid Volvulus?
Twisting of the colon resulting in bowel obstruction.
Can be congenital or aquired later in life.
Bowel at risk of infarction
What is the treatment for Sigmoid volvulus?
Emergency surgery to prevent infarction
Symptoms are campaction of stool and pain due to necrosis
Where is the abdominal arota found?
Midline, retroperitoneal, anterior to vertebral bodies and LEFT of IVC
What are the lateral branches of the abdominal aorta?
Renal artery L1
Gonadal artery at L2
Lumbar arteries supplying the posterolateral body wall
Where does the abdominal aorta bifurcate and what does it bifurcate into?
L4 (same level of the top of the iliac crest.
Common iliac arteries.
Further bifurcation into the internal and exteranl iliac arteries
What are teh branches of the SMA?
1) Inferior pancreaticoduodenal artery (anastamoses with the superior pancreaticoduodenal artery of the foregut)
2) Middle colic artery (supplies the transverse colon)
3) Right colic artery (supplies the ascending colon)
4) Ileocaecal branches (supplies the caecum and ascending colon)
5) Appendicular (runs within the mesoappendix)
6) Jejunal and ileal arteries (many of these
What level do the coelic, SMA adn IMA leave the aorta?
Coeliac = T12 SMA = L1 IMA = L3
What are the features of the jejuna arteries?
Longer vasa rectae
Langer and fewer arterial arcades
What are the features of ileal arteries?
Shorter vasa rectae
Smaller and many arcades
What re the branches of the IMA?
1) Left colic artery (supplies the descending colon)
2) SIgmoid arteries (multiple)
3) Superior rectal artery
What is the marginal artery of Drummond?
Arterial anastamosis between the hind gut and mid gut. Middle colic (SMA) and Left colic (IMA) join.
What is the function of the marginal artery of Drummond?
Collateral route for blood to prevent intestinal ischmia and infarction if there is an obstruction
Where does the hindgut end?
Pectinate line. After the proximal half of the anal canal- this is supplied by the superir rectal artery.
What supplies the most distal part of the GI tract?
Internal iliac artery => Middle and inferior rectal arteries.
There is an arterial anastamosis around the rectum. What vessels is this between?
Middle rectal artery (Interanl iliac artery)
Superior rectal artery (IMA)
What are the major veins forming the portal venous system?
Hepatic portal vain made up of the Splenic vain and the superior mesenteric vain.
The inferior mesenteric vein drains into the splenic vein.
All the venous system is retro/intraperitoneal?
Retroperitoneal
What is a portal systemic anastamosis?
Venous anastamosis where blood can flow into the systemic or portal venous system because the portal system has no valves.
Where are the 3 clinically important sites of portal systemic anastmosis?
1) Skin around umbilicus
2) Rectum/anal canal
3) Distal end oesophagus
Which veins formthe umbilical anastamosis?
Paraumbilical veins and epigastric veins
Paraumbilical vains drain to the hepatic portal vein along the round ligamant of the liver
Epigastric veins drain into the systemic system
Which veins for the anastamosis it the rectum/anal canal?
Inferior mesenteric vein (portal) and the internal iliac vein (systemic)
Which veins form the anastamosis at the distal end of the oesophagus?
Left gastric vein (portal) and the azygous vein (systemic)
What is portal hypertention and what are the consequences?
Elevation of BP in the portal system (normally due to liver disease)
Leads to reversal of blood flow- no valves. => Larger volumes of blood in venous anastamosis causing them to become dilated and varicose.
What are the consequences of varicose anastamoses?
Oesophageal varices, Caput medusae (external on abdomen) Rectal varicies (=> rectal bleeding as they burst on deffication (increased pressure))
What can cause haematemisis?
Peptic ulcers in stomach or duodenum
Oesophageal varicies
What is the function of the rectum?
Store faeces until it is appropriate to defficate
Which nerve fibres sense fullness in the rectum?
Stretch receptors linked to visceral afferent neurones
Normal cerebral function is required to control the appropriate time to defficate. What neural pathologies can lead to incontinence?
Dementia, stroke, MS, trauma (spinal cord or during childbirth)
Apart form the cerebral function, what else can effect faecal continence?
Medications
Age-relatedegeneration of nerves
Consistency of stool
Describe the position of the pelvic cavity?
Located within the boney pelvis and is continuous with the abdominal cavity (only separated by peritoneum)
Lies between the pelvic inset and the pelvic floor.
Formed by the 2 boes of the pelvis and bridged by the sacrum at the back.
Where is the rectum found?
Pelvic cavity
How many holes in the pelvic floor in males and females?
Males = 2 (anal canal and urethra (semen enters here) Female 3 (anal canal, urethra, cervix
Where is the perineum?
Beneath the pelvic floor
At what level does the sigmoid colon become the rectum?
S3
At what level does the rectum become the anal canal?
Coccyx
What is the anus?
The orifice through which faeces pass
Where is the anal canal and anus?
Perineum
Does the rectum have haustra?
No
How many lateral folds does the rectum have and what is their function?
3 lateral folds which allow for expansion and prevent tearing
Where is the rectal ampulla and what is its function?
Immediately superior to the levator ani muscle.
Its walls relax to accommodate faecal material. Full of stretch receptors
What are the anatomical relations of the rectum in the male?
Peritoneum covers superior rectum.
Rectovesical pouch lies anterior to superior rectum
Prostate gland lie anterior to the inferior rectum
What are the anatomical relations of the rectum in the female?
Peritoneum covers superior rectum.
Rectouterine pouch of douglas lies anterior to superior rectum
vagina and cervix lie anterior to the inferior/middle rectum
Which muscles make up the pelvic floor?
Levator Ani muscle
Coccygeus muscle
What are the 3 muscle fibres within the Levator Ani muscle from medial to lateral?
Puborectalis
Pubococcygeus
Iliococcygeus
Named by origins and insertions
What type of muscle is the pelvic floor and what is its function?
Skeletal and is under conscious contraol.
Prevent abdominal organs falling out when intra abdominal pressure increases eg coughing or straining
Tonically contracted most of the time.
When must the pelvic floor relax?
To allow defecation and urination to occur.
Which nerves supplies the lavator ani?
Duel supply
Branch of the sacral plexus
Pudendal nerve (S2, 3, 4)
S2, 3, 4 keep the guts of the floor
Which muscle within the levator ani muscle is the most impotant for maintaining faecal continence and why?
Puborectalis
Acts like a functional sphincter.
Contraction of the muscle decreases the anorectal angle inhibiting the passage of faeces.
When the rectal ampulla is relaxed and filled with faeces, contraction of this muscle will help to maintain continence.
What is the anal cushion?
Vasculature in the walls of the anal canal
What type of muscle is the internal and external anal sphincter?
Internal is just a thickening of the involuntary circular smooth muscle in the GI tract.
External anal sphincter is skeletal muscle uder voluntary control.
Where are the internal and external anal sphincters found?
Internal is the superior two thirds of the anal canal
External is the inferior two thirds of the anal canal.
What stimulates contraction of the internal anal sphincter?
Sympathetic nerves.
Therefore relaxation is triggered by parasympathetic nerves
When does the internal anal sphincter relax?
Reflexively in response to distention of the rectal ampulla
What stimulates contraction of the external anal sphincter?
Pudendal nerve and is voluntarily contracted (with puborectalis) in response to rectal ampulla distention and internal anal sphincter relaxation
Below the pelvic floor is the body wall. WHich nerves supply this area?
Somatic sensory and motor
Above the pelvic floor is the body cavity. WHich nerves supply this area?
Autonomic nerves (parasympathetic and sympathetic) Visceral afferents
What is the sympathetic outflow in general and which sympathetics supply the rectum?
Sympathetic outflow is T1-L2 (thoracolumbar)
To the rectum is T12-L2.
Where do the sympathetics to the rectum synapse?
Not in the sympathetic chain but in the inferior mesenteric pre-vertebral ganglia
What path do the sympathetic nerves take to the rectum?
Piggy back on the IMA and then in periarterial plexuses around branches of the IMA including the superior rectal artery
What is the function of sympathetics to the rectum?
Contract the internal anal sphincter and inhibit peristalsis
What is the parasympathetic outflow to the hind gut, including the rectum?
S2, 3, 4
NB: Not the same as the pedendal nerve which is somatic motor
What path do parasympathetic fibres take to the rectum?
Pelvic splanchnic nerves which synapse in the walls of the rectum
What is the function of parasympathetics to the rectum?
Faeces impact the ampulla and stretch receptors activate visceral afferent which reflect back down the parasympathetic outflow to relax internal anal sphincter and stimulate peristalsis
Where to the visceral afferents from the rectum travel back to?
S2, 3, 4. (Run with parasympathetics and sense stretch and ischemia
What is the pudendal nerve?
Branch of the sacral plexus. S2, 3, 4 anterior rami
What is the path of the pudendal nerve?
Exits the pelvis via greater sciatic foramen and enters the perineum via lesser sciatic foramen.
Branches to supply structures of the perineum
What damage can occur during child birth which may lead to incontinence?
Branches of the pudendal nerve may be stretched
Fibres within the puborectalis or external anal sphincter may be torn
What is the pectinate line?
Marks the junction between the part of the embryo which formed the GI tract- endoderm and the part that formed the skin- excoderm
Why is the pectinate line important?
Arterial supply, venous and lymph drainage and nerve supply is different above and below the line.
Above = visceral
Below = Parietal
What is the nerve supply, arterial supply, venous dranaine and lymphatic drainage from ABOVE the pectinate line?
Nerve supply = autonomic
Arterial supply = From the IMA
Venous drainage = IMV into the hepatic portal system
Lymphatic drainage = Inferior mesenteric lymph nodes via internal iliac nodes
What is the nerve supply, arterial supply, venous dranaine and lymphatic drainage from BELOW the pectinate line?
Nerve supply = somatic
Arterial supply = From internal iliac artery
Venous drainage = Internal iliac vain to the systemic venous system
Lymphatic drainage = Superficial inguinal nodes
What are the main groups of lymph nodes draining the pelvic organs ?
Internal illiac (inferior pelvic structures) External iliac (draining lower limb and superior pelvic structures) Common iliac (Joining of vessels above) Lumbar nodes which surround the aorta => thoracic duct
What is the cause of rectal varicies?
Portal hypertension => dilation of the collateral veins between the portal and systemic circulations in the rectum
What are haemorrhoids?
Prolapses of the rectal venous plexuses and dilation of anal cushions
What causes haemorrhoids?
Raised pressure due to chronic constipation, straining or bearing down.
Also in pregnancy
What is the difference in pain between internal and external haemorrhoids?
Internal= less painful External = more painful
What is the ischioanal fossa?
Spaces which lie on the right and left side of the anal canal (communicate posteriorly) filled with fat and lose connective tissue.
What is an infection in the ishioanal fossa called and what are the consequences?
Caused by a fistulla into the anal canal.
Called and ishioanal abscess.
Not much pain and the infection can spread all the way around the back
What is a proctoscopy?
Scope to see the rectum.
What are you checking on a PR exam?
Anal tone,
Prostate/Cervix
