Anatomy Flashcards
What structures make up the Upper GI tract?
oral cavity oropharynx laryngopharynx oesophagus stomach small intestine (duodenum, jejunum, ileum)
What structures make up the lower GI tract?
caecum appendix colon rectum (these are all large intestine) anal canal anus
How do we ensure that we get food and drink safely into and out of our stomach?
- poisons - many have a bitter taste which is detected by our taste buds
- sharp or extremely hot/cold substances - sensory receptors for pain and temperature
- bacteria/pathogens - saliva, tonsils, stomach acid
- obstructions in oesophagus - chewing, lubrication, peristalsis
- aspiration into respiratory tract - cough reflex
what function does the palate serve?
It separates the nasal cavity from the oral cavity
How many pairs of muscles of mastication are there and what are they?
4 masseter temporalis medial pterygoid lateral pterygoid
What are the three main components of the temporomandibular joints?
head of the condylar process of the mandible mandibular fossa (of the temporal bone) articular tubercle (of the temporal bone)
What type of joint are the TMJ’s?
synovial
What joint do the muscles of mastication span and what movements do they bring about?
temporomandibular joints
jaw opening and jaw closing
Describe the muscles of facial expression.
A group of skeletal muscles which attach to the bones of the face and the superficial fascia, just deep to the skin of the face.
When they contract they pull the face into expressions
What does the orbicularis oris do?
muscle of facial expression arranged circularly around the lips. Contract to pull the lips together and create an anterior oral seal to prevent drooling.
What is the name of the tonsils in the oral cavity that are commonly involved in tonsilitis?
palatine tonsils
What type of mucosa lines the mouth?
Stratified squamous epithelium which is non-keratinised apart from on the gingivae and hard palate - these are the only structures covered in keratinised stratified squamous epithelium to protect the mechanical damage by chewing.
Which part of the tongue is visible in the oral cavity?
the anterior two thirds (the posterior third is the vertical part that forms the anterior part of the pharynx)
What are the four types of papilla and what are the functions of each?
folliate, vallate and fungiform papillae are all for taste
filliform papillae are for general sensations
What are the muscles of the tongue and what do they do?
extrinsic muscles: 4 pairs - attach the tongue to the oral cavity, attach external to the tongue and insert into the tongue, move the tongue around the oral cavity during speech and mastication
intrinsic muscles: lie just deep to the mucosa of the tongue, modify shape of the tongue during function.
What is the name of the muscle of the cheek and what does it do?
Buccinator - runs from anterior to posterior
Helps the tongue to position the food bolus between the occlusal surfaces of the teeth during mastication
What should you ask the patient if you suspect a fractured mandible or maxilla and why?
“How does your bite feel?”
a fractured mandible or maxilla will change the occlusion and patients are very sensitive to changes in occlusion
What are the three major pairs of salivary glands?
parotid, submandibular and sublingual
What stimulates saliva production?
Sight, smell, thought of food or presence of food in the mouth
painful oral conditions eg fractured mandible or teething
What is the function of the minor salivary glands and where are they?
thousands in the oral mucosa - background and continuous saliva secretion to keep oral mucosa moist.
Describe the mucosa of the pharynx.
non-keratinised stratified squamous epithelium, containing tonsils
Describe the muscles in the pharynx.
Skeletal muscle that goes round the tube, but not all the way round (incomplete tube)
What is Waldeyer’s ring?
Tonsils (part of the lymphatic system) in the mucosa of the naso- and oro-pharynx which contain white blood cells and help to defend against pathogens.
What is the opening into the larynx called?
laryngeal inlet
What is the function of the uvula of the soft palate and the epiglottis?
to guide the food bolus away from the laryngeal inlet.
What are the two layers of muscles in the pharynx?
inner layer: longitudinal muscles of the pharynx - arranged vertically
outer layer: constrictor muscles of the pharynx - arranged circularly.
What is are the functions of the two layers of pharyngeal muscles?
inner longitudinal muscles: contract to shorten the length of the pharynx to reduce bolus transit time and raise the larynx to the epiglottis to cover the laryngeal inlet
outer constrictor muscles: contract sequentially to push food bolus inferiorly into the oesophagus - peristalsis
Describe the location and function of the oesophagus.
inferior continuation of the pharynx, lies posteriorly to the trachea
conduit for food and drink to the stomach
muscular tube which consists of skeletal muscle proximally which gradually changes to smooth muscle distally - muscles contract in peristalsis
lined by non-keratinised stratified squamous epithelium to protect it from mechanical damage (as opposed to chemical damage)
What are the two muscle layers of the small intestine and what do they do?
inner circular - constricts lumen
outer longitudinal - shortens the tube
these muscles are for peristalsis.
Which structure marks the end of the upper GI tract?
ileocaecal junction
What forms the roof of the pelvic cavity?
parietal peritoneum
What associations with the visceral peritoneum do the intraperitoneal, retroperitoneal and meseteric organs have.
Intraperitoneal: not in the peritoneal cavity but organ is covered with a layer of visceral peritoneum - minimally mobile
Retroperitoneal: organs are stuck to the posterior abdominal wall - only anterior surface is covered by visceral peritoneum
Mesenteric: organ is covered by visceral peritoneum and suspended from the posterior abdominal wall by a mesentery (a double layer of visceral peritoneum) - highly mobile organs
What structures are within the mesentery that pass between intestines and retroperitoneum?
arteries, veins, nerves and lymphatics
What is peritonitis?
severe, painful inflammation of the peritoneum which can be life threatening. Can be caused by blood, pus or faeces in the peritoneal cavity.
What are the organs of the foregut?
oesophagus to mid-duodenum, liver, gall bladder, spleen, half of the pancreas
What are the organs of the midgut?
mid duodenum to proximal 2 thirds of the transverse colon, half of the pancreas
What are the organs of the hindgut?
distal third of the transverse colon to the proximal half of the anal canal
What part of the abdominal cavity are the IVC and abdominal aorta contained in?
retropritoneum
What are the three branches of the abdominal aorta and what to they supply?
- coeliac trunk - foregut organs
- superior mesenteric artery - midgut organs
- inferior mesenteric artery - hindgut organs
Where are the branches of the superior and inferior mesenteric arteries?
superior mesenteric artery: mesentery of the small intestine
inferior mesenteric artery: mesentery of the sigmoid colon
What vein drains blood from the foregut, midgut and hindgut and where does it drain to?
hepatic portal vein
to the liver
Which veins drain into the hepatic portal vein and which structures do they drain?
splenic vein - drains the structures of the foregut
superior mesenteric vein - drains structures of the midgut
inferior mesenteric vein - drains structures of the hindgut and drains into the SPLENIC VEIN before draining into the hepatic portal vein.
What kind of blood is in the hepatic portal vein?
oxygen depleted but nutrient (and toxin) rich
What is the lymphatic drainage of the foregut, midgut and hindgut structures?
foregut: drains lymph via lymph nodes that go along the splenic artery towards the coeliac nodes which are located at the origin of the coeliac trunk
midgut: drains lymph via lymph nodes that go along the superior mesenteric artery towards the superior mesenteric nodes located at the origin of the superior mesenteric artery
hindgut: drains lymph via nodes that go along the inferior mesenteric artery to the inferior mesenteric lymph nodes located at the origin of the inferior mesenteric artery
What is “guarding”?
contraction of the abdominal wall muscles to protect the abdominal organs from threatening injury
occurs in peritonitis
What are the anatomical sphincters of the GI tract?
cricopharyngeal sphincter (between laryngopharynx and oesophagus) pyloric sphincter (between stomach and duodenum) external anal sphincter
What causes colicky pain?
Pain that comes and goes caused by increased peristalsis proximal to an obstruction in an attempt to dislodge it.
Which cranial nerve supplies the muscles of mastication?
CN III/trigeminal - madibular division
Which cranial nerve is responsible for the special sensation of taste to anterior two thirds of tongue?
CN VII - facial
CN IX is responisble for taste on the posterior third of the tongue
What are the 4 extrinsic muscles of the tongue and which cranial nerve supplies them (as well as the intrinsic muscles of the tongue)?
palatoglossus styloglossus hyoglossus genioglossus muscles of the tongue are supplied by CN XII (hypoglossal)
What is the gag reflex and what fibres of which cranial nerve are responsible for it?
protective reflex in response to touching the posterior wall of the oropharynx to close the pharynx and prevent entry of a foreign body to the larynx or pharynx.
sensory component: reflex fibres of CN IX
motor component: motor fibres of CN IX and X
What type of muscle are the muscles involved in initiation of swallowing?
Skeletal
Where to the parotid ducts enter the oral cavity?
opposite the upper second molar
Where to the submandibular ducts enter the oral cavity?
Base of the ligular frenulum
Where do the sublingual ducts enter the oral cavity?
at the floor of the mouth
What are the three outer constrictor (circular) pharyngeal muscles?
superior, middle and inferior pharyngeal constrictors
What is the circular muscle of the upper oesophageal sphincter and what level is it at?
cricolaryngeus
C6
What is the oesophageal plexus?
Group of vagus trunks (parasympathetic) and sympathetic fibres which travel down the surface of the oesophagus and supply its muscular walls. Influence the enteric nervous system to either speed up (parasympathetic) or slow down (sympathetic) peristalsis.
Where does the oesophagus terminate
Where it enters the cardia of the stomach
What type of sphincter is the lower oesophageal sphincter?
physiological
How many normal constrictions does the oesophagus have?
3
What are the normal constrictions of the oesophagus?
- cervical - due to the cricopharyngeus muscle (upper oesophageal sphincter)
- thoracic - due to aortic arch and left main bronchus
- diaphragmatic - lower oesopahgeal sphincter - as the oesophagus passes through the diaphragm
Describe the lower oesophageal sphincter and name the condition that affects its function.
lower oesophageal sphincter is a physiological sphincter
its function is to prevent reflux from the stomach back into the oesophagus
this is achieved by:
- the contraction of the diaphragm around the distal oesophagus
- the slightly higher intra-abdominal pressure than intra-gastric pressure
- the oblique angle at which the oesophagus enters the cardia of the stomach
hiatus hernia affects the function of this physiological sphincter
What feature marks the abrupt change in mucosa from oesophageal to gastric?
Z-line
What are the names of the superior part, main part and outflow parts of the stomach?
superior = fundus
main =body
outflow = pyloris antrum
What is the feature which marks the junction between the body and pyloris antrum of the stomach?
incisura angularis
What is ascitic fluid?
excess fluid in the peritoneal cavity
Where should the needle be placed for paracentesis and why?
lateral to the rectus sheath to try to avoid the internal epigastric artery which runs up the anterior abdominal wall
What structure of peritoneum attaches the liver to the abdominal wall?
falciform ligament
What structure of peritoneum attaches the stomach to the liver?
lesser omentum
What structure of peritoneum attaches the stomach to the transverse colon?
greater omentum
What is the lesser sac?
small part of the peritoneal cavity posterior to the stomach which is separated from the greater sac by the omenta
What is the name of the structure that allows communication between the greater and lesser sacs?
omental foramen
What are the names of the most inferior pouches of peritoneum that drape over the pelvic organs in the male and female?
Male: rectovesical pouch (between rectum and bladder)
Female: uterovesical pouch (between uterus and bladder) and rectouterine pouch (between rectum and uterus) - the pouch of Douglas (most inferior)
Where is pain from the foregut, midgut and hindgut felt?
foregut: epigatric
midgut: umbilical
hindgut: suprapubic
What is referred pain?
When pain fibres of organ enters the spinal cord at the same level of the dermotone of a certain region of the soma and the pain is perceived in this region.
What pathologies can cause referred pain in the shoulder and why?
pathologies of the liver and gall bladder as these can irritate the diaphragm (enters the spinal cord at C3,4,5 and so does the dermatone for the shoulder tip)
Where is the portal triad located?
In the free edge of the lesser omentum
What makes up the portal triad?
hepatic portal vein, hepatic artery and common bile duct
The coeliac trunk trifurcates into what three arteries?
heptic artery, splenic artery and left gastric artery
Which ribs protect the spleen?
9-11
Where is the spleen located?
left hypochondrium, intraperitoneal, posterior to the stomach, lateral to the left kidney, anterior and inferior to the diaphragm and superior to the splenic flexure of the colon.
What is the blood supply to the stomach?
Left (branches off coeliac trunk) and right (branches off hepatic artery) gastric arteries and the let and right gastro-omental arteries (these anastomose just inferior to the stomach)
How many segments of the liver are there?
8
How does blood drain from the liver to the IVC?
3 main hepatic veins
What is the effect of a rise in central venous pressure on the liver and why?
Rise in central venous pressure (eg due to right sided/congestive cardiac failure) results in a back pressure on the hepatic veins, since these don’t have any valves, and the result is hepatomegaly
How many lobes does the liver have and what are they called?
4 - right, left, caudate, quadrate
What are the two clinically important areas of peritoneal cavity around the liver?
subphrenic recess
hepatorenal recess
What is the ligamentum teres?
On the liver inferior to the falciform ligament - it is the remnant of the embryological umbilical vein
What vessel supplies blood to the gall bladder and where does it usually branch from?
cystic artery - branches from the right hepatic artery
How does bile enter and leave the gall bladder?
via the cystic duct
Where is the gall bladder located?
lies on the posterior aspect of the liver and anterior to the duodenum
What forms the common hepatic duct?
cystic duct and hepatic duct
