Anatomy Flashcards
What are the components of the GI tract?
Oral cavity Pharynx Oesophagus Stomach Small intestine Large intestin Rectum Anal canal Anus
What are the functions of the upper GI tract?
Mastication
Taste
Salivation
Deglutition (swallowing)
What is mastication?
The process of chewing which is conducted by movement of the jaw and tongue to breakdown food. Mastication facilitates taste and digestion by mixing food with saliva
What is the buccinator?
A muscle inside the cheek that pushed food from side to side innervated by cranial nerve 7
What are the oestology features of the TMJ?
Temporal bone has a mandibular fossa where the condylar process (of mandible) can fit in. The articular tubercle is a bump in the zygomatic arch and lies anteriorly to the TMJ
What are the muscles of mastication innervated by?
CN V3 (mandibular division of the trigeminal nerve)
Which muscles facilitate closing of the jaw?
Temporalis (temple fossa to the coronoid process)
Masseter (angle of the mandible to the zygomatic arch)
Medial pterygoid (mimics masseter on the internal surface)
Which muscle facilitates the opening of the jaw?
Lateral pterygoid (condyle of mandible to the pterygoid plates of sphenoid bone)
What does the articuar disc in the TMJ separate?
Two cavities - superior caivty for translation and inferior cavity for rotation
What is the course of the trigeminal nerve?
From pons through the foramen ovale to the muscles of mastication and sensory area
What is the sulcus terminalus?
Divides the tongue into the anterior and posterior tongue
What is the function of the vertical part of the tongue?
Taste and sensation innervated by glosopharyngeal nerve
What is the function of the horizontal part of the tongue?
Taste - innervated by the facial nerve
General sensory - innervated by the V3
What are the papillae with taste buds?
Foliate papillae
Vallate papillae
Fungiform papillae
What is the papillae that detects touch and temperature?
Filiform papillae
What is the course of the facial nerve?
From pontomedullary junction travels through the temporal bone via interal acoustic meatus and then through the stlomastoid foramen to supply taste to the anteroir 2/3rds of tongue, muscles of facial expression and glands in the floor of the mouth
What innervates the superior half of the oral cavity?
Maxillary division of the trigeminal nerve
What innervates the inferoir half of the oral cavity?
Mandibular division of the trigeminal nerve
What is the gag reflex?
A protective reflex that prevents foreign bodies from entering the pharynx or larynx
What innervates the sensory part of the gag reflex?
Nerve fibres within the glossopharyngeal nerve
What carries out the motor part of the gag reflex?
Nerve fibres within the glossopharyngeal nerve and vagus nerve
What does the gag reflex do to the pharynx?
When the posterior wall of the oropharynx is touched the pharynx constricts
What is the course of the maxillary division of the trigeminal nerve?
From pons through the formaen rotundum to the sensory area (mid-face)
What is the course of the glossopharyngeal nerve?
From medulla through the jugular foramen to the posterior wall of the oropharynx (sensory), parotid gland (secretomotor) and posterior 1/3rd of the tongue (sensation and taste)
Where does the parotid gland secrete saliva?
Parotid duct secretes into mouth by upper 2nd molar (upper 7th)
Where does the submandibular gland secrete saliva?
The submandibular duct enters the floor of the mouth and secretes via lingual caruncle
Where does the sublingual gland secrete saliva?
Lays in the floor of mouth and secretes via several ducts superiorly
What is the function of the extrinsic muscles of the tongue?
Change the position of the tongue during mastication, swallowing and speech
What is the function of the 4 pairs of intrinsic muscles of the tongue?
Located mainly dorsally to modify the shape of the tongue during function
What are the 4 intrinsic muscles of the tongue?
Palatoglossus - palate to tongue
Styloglossus - styloid process to the tongue
Genioglossus - chin to tongue
Hyoglossus - hyoid bone to tongue
What innervates all of the tongue muscles (except the palatoglossus)?
Hypoglossal nerve
What is the course of the hypoglossal nerve?
Medulla through the hypoglossal canal to the extrinsic and intrinsic muscles of the tongue
What innervates the constrictor muscles pharynx?
Vagus nerve
What is the function of the upper oesophageal sphincter?
To prevent reflux at level of C6 as it attaches to cricoid cartilage
What is the midline raphe?
Where all of the 3 circular constrictor muscles insert into
What innervates the longitudinal muscles of the pharynx?
Vagus and glossopharyngeal
What is the function of the longitudinal muscles?
Attach to pharynx and larynx to shorten the pharynx and raise the larynx to close over the laryngeal inlet
What is the anatomy of swallowing?
Close lips to prevent drooling (orbicularis and facial nerve
Tongue pushes bolus posteriorly towards oropharynx
Sequentially contract pharyngeal contrictor muscles to push the bolus inferiorly towards oesophagus
Inner longitudinal muscles contract to raise larynx, shorten the pharynx and close the laryngeal inlet
Bolus reaches oesophagus
Where does the oesophagus start?
At the inferior edge of criopharyngeus muscle (vertebral level C6)
What are the sphincters present in the oesophagus?
Anatomical upper sphincter (cricopharyngeus) and a physiological lower oesophageal sphincter which aids in controlling food movement
What is the oesophageal plexus?
Runs on the surface to supply smooth muscle within its walls (distally)
What does the oesophageal plexus contain?
Parasympathetic nerve fibres (vagal trunks) and sympathetic nerve fibres
What do these autonomic nerve fibres of the oesophageal plexus do?
They influence the enteric nervous system to speed up (P) or slow down (S) peristalsis
Terminates by entering the cardia of the stomach
Where does the oesophagus pass through the diaphragm?
At T10
What heart ventricle does the oesphagus pass under?
The left atrium
What factors influence the lower oesophgeal sphincter effect?
Contraction of diaphragm
Intrabdominal pressure if it is slightly higher that intragastric pressure
Oblique angle at which oesophagus enters the cardia of the stomach
What does the lower oesohpageal sphincter help to reduce?
The occurrence of reflux `
What is the z-line?
An abrupt change in the type of mucosa lining of the wall
What are the different parts of the large intestine?
Colon Caecum Appendix Ascending colon Transverse colon Descending colon Sigmoid colon Rectum Anal canal Anus
What makes up the foregut?
Oesophagus to mid-duodenum
Liver and gall bladder
Spleen
1/2 of pancreas
What supplies the foregut?
Celiac trunk
What makes up the midgut?
Mid-duodenum to proximal 2/3rds of transverse colon
1/2 of pancreas
What makes up the hindgut?
Distal 1/3rd of transverse colon to proximal 1/2 of anal canal
What supplies the midgut?`
Superior mesenteric artery
What supplies the hindgut?
Inferior mesenteric artery
What organs make up the RUQ?
Liver Gallbladder Duodenum Head of pancreas Right kidney and adrenal gland Hepatic flexure of colon
What organs make up the LUQ?
Stomach Spleen Left lobe of liver Body of pancreas Left kidney and adrenal gland Splenic flexure of colon Parts of transverse and descending colon
What organs make up the RLQ?`
Cecum Appendix Ascending colon Right ovary and fallopian tube Right ureter
What organs make up the LLQ?
Small bowel (ileum) Transverse colon Descending colon Sigmoid colon Rectum Left ureter Left ovary and fallopian tube
What are the muscles of the anterolateral abdominal wall?
Rectus abdominus External oblique Interal oblique Transversus abdominus Parietal peritoneum
What is peritoneum?
A thin, transparent, semi-permeable, serous membrane
What does the peritoneum line?
The walls of the abdominopelvic cavity and organs
What is peritonitis?
Blood, pus or faces in the peritoneal cavity will cause severe and painful inflammation of the peritoneum (peritonitis)
What are intraperitoneal cavities?
Almost completely covered in visceral peritoneum
Minimally mobile
What are organs with a mesentery (intraperitoneal)?
Covered in visceral peritoneum
Visceral peritoneum wraps behind the organ to form a double layer - mesentery
Mesentery suspends the organ from the posterior abdominal wall - very mobile
What is a retroperitoneal organ?
Only has visceral peritoneum on its anterior surface in the retroperitoneum
What are intraperitoneal organs?
Liver and gall bladder Stomach Spleen Parts of small intestine Transverse colon
What are retroperitoneal organs?
Kidneys Adrenal gland Pancreas Ascending colon Descending colon
What are the different types of peritoneum?
Mesentery - usually connects organ to posterior body wall
Omentum (greater and lesser) - double layer of peritoneum that passes from stomach to adjacent organs
Peritoneal ligaments - double layer of peritoneum connects organs to one another or body wall
What makes up the mesentery?
Have a core of connective tissue with blood and lymph vessels, nerve, lymph nodes and fat
What are the 3 types of mesentery?
Mesentery proper (small intestine)
Transverse and sigmoid mesocolon
Mesoappendix
What is the function of the greater omentum?
Four layered
Hangs like an apron
Attaches the greater curvature of stomach to the transverse colon
What is the function of the lesser omentum?
Double-layered
Runs between lesser curvature of stomach and duodenum to the liver
Has a free edge
What are the sacs in the peritoneum?
The omenta divide the peritoneal cavity into the greater and lesser sacs
What is the omental foramen?
How the greater and lesser sacs communicate
What is the portal trial?
Hepatic portal vein, hepatic vein proper and common bile duct
Where is portal triad?
It lies in the free edge of the lesser omentum in the hepatoduodenal ligament
What are the pouches that are formed by the peritoneum in the female?
Recto-uterine pouch known as the pouch of douglas
Vesico-uterine pouch
What is ascites?
Collection of fluid in the peritoneal cavity
What commonly causes ascites?
Cirrosis
Portal hypertension
How can ascitic fluid be drained?
Via paracentesis
Where is the needle inserted in abdominocentesis?
Placed lateral to the rectus sheath to avoid the inferior epigastric artery
Where does the inferior epigastric artery arise from?
The external iliac medial to the deep inguinal ring
What does organ pain tend to present as?
Dull, achy and nauseating
What does somatic pain present as?
Sharp and stabbing
What is the enteric nervous system?
A network of nerves found only within the walls of the GI tract which can act independently of other part of the the nervous system to bring about peristalsis but can also be influenced by autonomic motor nerves
Where do sympathetics that innervate the abdomen leave the spinal cord?
Between T5 and L2
Where do the sympathetic nerves synapse?
They synpase at the prevertberal ganglia which are located anterior to the aorta at the exit points of the major branches of the abdominal aorta
What are the 3 different ganglion within the abdomen?
Celiac ganglion
Superior mesenteric ganglion
Inferior mesenteric ganglion
Where do sympathetic fibers for the adrenal gland leave the spinal cord and where do they synpase?
T10-L1 and enter the abdominopelvic splanchnic nerves but do not synapse at prevertebral ganglia but instead are carried with the periarterial plexuses to the adrenal gland and synapse directly onto cells
What is the course of the vagus nerve when innervating the abdomen?
Presynaptic nerve fibres enter abdominal cavity on the surface of the oesophagus and travel into the periarterial plexuses around the abdominal aorta. Here they are carried to the walls of the organs where they synapse and supply to GI tract and abdominal organs up to the dital end of the trasnverse colon
What do the pelvic splanchinic nerves supply?
S2,3,4 supply smooth muscle/glands of the descending colon to anal canal
What does foregut pain present as?
Epigastric pain
What does midgut pain present as?
Umbilical pain
What does hindgut pain present as?
Pubic region
Where doe foregut structures enter the spinal cord?
T6-T9
Where do midgut structures enter the spinal cord at?
T8-T12