Flashcards in GI Anatomy - Abdominal Pain Deck (79):
Name the four muscles of mastication
Temporalis, Masseter, Lateral & Medial Pterygoid
What is the function of Mastication?
To breakdown food
Conducted by movement of jaw and tongue
Muscle within cheek
Contraction pushes food from cheek into cavity. Innervated by CN VII
Where does the Parotid Gland secrete it's fluid?
Upper right 2nd molar (7)
What are the 3 components of the TMJ?
Mandibular Fossa (condylar fits snuggly and allows hinge)
Articular Tubercle, Condylar Process
Innervation of the muscle of mastication?
CN V3 - Mandibular Division of Trigeminal Nerve (foramen = foramen ovale)
Attachments of the muscles of mastication?
Temporalis: temporal fossa > coronoid process
Masseter: mandible angle > zygomatic arch
Medial Pterygoid: mandible angle > pterygoid plates of sphenoid bone
Lateral Pterygoid: mandible condyle > pterygoid plates
What do the 2 cavities of the TMJ allow?
Superior cavity = Translation
Inferior cavity = Rotation
Describe the path of CN V3?
From pons > through foramen ovale (middle cranial fossa) > enters infra-temporal fossa > to muscles of mastication & sensory area
Name the 4 papillae?
Foliate papillae (side of tongue)
Vallate papillae (V-shaped)
Fungiform papillae (middle of tongue)
Filiform papillae (tip of tongue, touch, temp, etc.)
What is the innervation of the tongue?
CNV3 - general sensory
CN VII - taste (anterior)
CN IX - taste and general sensation (posterior)
Describe the path of CN VII?
From Pontomedullary junction > travels through temporal bone via internal acoustic meatus > through stylomastoid foramen > travels with Chorda Tympani and connects to lingual nerve (CN V3)
What does CN VII innervate?
Taste to anterior 2/3rds of tongue (parasym.)
Muscles of facial expression
Glands in floor of mouth (sublingual + submandibular)
Branch of facial nerves that originates from the taste buds in the front of the tongue, rungs through the middle ear and carries taste messages to the brain
What is the nerve supply of the oral cavity?
Superior half - CN V2
Inferior - CN V3
What nerves need to be 'blocked' with an anaesthetic before an endoscopy?
Explain the gag reflex?
= a conscious, protective reflex that prevents foreign bodies entering the pharynx or larynx
Part of response is constriction of the pharynx if the posterior wall of the oropharynx is touched
Describe the path of CN V2 (Maxillary)?
From pons > through foramen rotundum > to sensory area (mid-face)
Describe the path of CN IX?
From Medulla > through jugular foramen > to posterior wall of oropharynx (sensory), parotid gland (secretomotor), post. 1/3rd tongue (sensation + taste)
Which cranial nerves innervate the salivary glands?
Parotid - CN IX
Submandibular - CN VII
Sublingual - CN VII
What is the secretion site of the Submandibular Gland and the Sublingual Gland?
Submandibular - enters floor of mouth and secretes via LINGUAL CARUNCLE
Sublingual - lays in floor of mouth and secretes via several ducts superiorly
What can happen if the salivary glands are blocked/clogged?
Swelling (due to back-up of secretions) > can result in pain if saliva not released
Name the 4 muscle of the tongue
All innervated by CN XII (EXCEPT PALATOGLOSSUS)
What is the function of the Extrinsic and Intrinsic muscles of the tongue
Extrinsic - change position of tongue during mastication, swallowing + speech
Intrinsic pairs - modify shape of tongue during function
Describe the path of CN XII?
From Medulla > through hypoglossal canal > to extrinsic and intrinsic muscles of tongue (except palatoglossus)
Which muscle of the tongue is NOT innervated by CN XII?
Palatoglossus (innervated by CN X - vagus)
What is the innervation of the muscles of the pharynx?
Circular, voluntary muscle = CN X
Longitundinal muscles (inner layer) = CN X + CN IX (1 muscle)
What significant junction occurs at C6?
Junction between pharynx + oesophagus = Upper Oesophageal Sphincter (cricopharyngeus muscle)
What is the function of the muscles of the pharynx?
- Attach to the larynx
- Raise the larynx to close over laryngeal inlet (elevate towards epiglottis)
- Contract and shorten pharynx
Which cranial nerves are involved in the anatomy of swallowing?
CN VII - orbicularis oris
CN XII - tongue
CN X - pharyngeal constrictor muscles
CN IX + X - longitudinal muscles of pharynx
What supplies the smooth muscle of the oesophagus?
(contains parasym. and sym. nerve fibres)
Fibres influence ENS to speed up or slow down peristalsis
Name some factors that produce the sphincter effect of the LOS (physiological sphincter)
- Contraction of diaphragm
- Intraabdominal pressure slightly higher than intragastric pressure
- Oblique angle at which oesophagus enters the cardia of the stomach
What can reduce the effectiveness of the LOS sphincter effect?
A hiatus hernia
Reduces effectiveness and can lead to symptoms of reflux
Name the 4 areas of the stomach
Cardia, Fundus, Body, Pyloric antrum
Angle created in the lesser curvature of the stomach
From proximal to distal, name the sections of the intestines (small and large)
Duodenum, Jejunum, Ileum, Caecum, Appendix, Ascending colon, Transverse colon, Descending colon, Sigmoid colon
Organs of the Foregut
Oesophagus to mid-duodenum
Liver + gall bladder
Organs of the Midgut
Mid-duodenum to proximal 2/3rds of transverse colon
Organs of Hindgut
Distal 1/3rd of transverse to proximal 1/2 of anal canal
Name the muscles of the anterolateral abdominal wall from superficial to deep
Rectus Abdominus (most anterior)
Muscles of abdomen become very rigid and locked down to protect the structures underneath with injury
(guarding also occurs in peritonitis)
= thin, transparent, semi-permeable, serous membrane that lines the walls of the abdominopelvic cavity and organs
Inflammation of the peritoneum
Possibly caused by blood, pus or faeces in the peritoneal cavity resulting in severe and painful inflammation
What abdominal organs are Intraperitoneal?
Liver + gallbladder
Parts of small intestine
What abdominal organs are Retroperitoneal?
Explain what is meant by intraperitoneal organs
Organs are almost completely covered in visceral peritoneum and minimally mobile
Explain what is meant by intraperitoneal organs with a mesentary
Visceral peritoneum covers the organ and wraps behind the organ to form a double layer (mesentery).
Mesentery suspends the organ from the posterior abdominal wall so it is very mobile
Explain what is meant by retroperitoneal organs
Only has visceral peritoneum in its anterior surface
Omentum (greater and lesser):
Double layer of peritoneum that passes from stomach to adjacent organs
Double layer of peritoneum connect organs to one another or body wall
What is contained within the core of connective tissue of the mesentery?
Blood, lymph vessels, nerves, lymph nodes, fat
The peritoneal process attaching the colon to the posterior abdominal wall
How does mesentery contribute to mobility?
Mesentery provides high level mobility
Where does the Greater Omentum attach?
Attaches the greater curvature of the stomach TO the transverse colon
It is 4-layered and hangs like an apron
Where does the Lesser Omentum attach?
Runs between the lesser curvature to stomach and duodenum TO the liver
It also has a free edge (Portal Triad lies in free edge)
How is the peritoneal cavity divided?
Omenta divides cavity into a Greater Sac and a Lesser Sac
(lesser sac is much smaller)
Where does the two sacs of the peritoneal cavity communicate?
Omental Foramen (Foramen of Winslow)
What structures lie within the Portal Triad?
The portal triad is composed of a branch of the hepatic artery, portal vein, and bile duct.
Where is the Portal Triad located?
Lies on the free edge of the lesser omentum
What 2 ligaments are located in the lesser omentum?
Explain the pouches formed in the greater sac
At the most inferior point the peritoneum 'drapes over' the superior aspects of the pelvic organs and forms pouches
How many pouches in the peritoneum are in men and women?
Men - 1 (retrovesical pouch)
Women - 2 (vesico-uterine pouch + recto-uterine pouch)
Recto-uterine pouch is also known as Pouch of Douglas
Abnormal collection of fluid in the peritoneal cavity
What are the most common causes of Ascites?
Cirrhosis (back-up of blood changes conc. gradient so that fluid is pushed out from vessels into peritoneal cavity)
+ Portal hypertension
Where is the needle placed for Abdominocentesis in treatment of Ascites?
- Placed lateral to rectus sheath (avoids inferior epigastric artery)
- Inferior epigastric arises from the enternal iliac medial to the deep inguinal ring
What 4 areas must be asked about for Abdominal Pain?
Location - localised, visceral or somatic (visceral is hard to localise, somatic is easier)
Character - visceral (dull, achy, nauseating) or somatic (sharp, stabbing)
Timing - come and go (colicky)
Referral Pattern - assoc. pattern with specific organ?
Enteric Nervous System:
= Extensive nerve network found only within the walls of the GI tract
(Can act independely on other parts of the NS to bring about peristalsis but can also be influenced by ANS nerves)
What impact does parasym. and sym. motor nerves (ANS) have on peristalsis?
Parasym. > speed up peristalsis
Sym. > slow down peristalsis
At what levels do sympathetic nerve fibres leave the spinal cord to reach the abdominal organs?
Between T5 and L2 (enter the sym. chains but do not synapse)
The sympathetic nerves leave the sym. chains within abdominopelvic splanchnic nerves
Where do the sym. nerves (with abdominopelvic splanchnic nerves) synapse at prevertebral ganglia?
Synapse at prevertebral ganglia located anterior to the aorta at the exit points of the major branches of the abdominal aorta
How do postsynaptic sym. nerve fibres reach the abdo. organs?
Pass from prevertebral ganglia onto surface of arterial branches leaving abdominal aorta.
Become part of Periarterial Plexus (with parasym. and visceral afferents) and 'hitch a ride' with the arteries towards the smooth muscle
How do sym. nerves to the adrenal gland differ from the other sym. nerves?
They DO NOT synapse at prevertebral ganglia > they synapse directly onto cells.
Sym. nerves leave spinal cord (T10-L1) > enter abdominopelvic splanchnic nerves > DO NOT synapse > carried in periarterial plexuses to adrenal gland > synapse DIRECTLY onto cells
Where do Pelvis Splanchnic nerves leave the spinal cord?
S2, 3, 4
Explain the path of parasym. nerves (CN X) from the CNS to the abdo. organs
- Presynaptic parasym. nerve enter abdominal cavity on surface of oesophagus
- Travel in periarterial plexuses around abdominal aorta
- Carried to organ walls where they synapse in ganglia
- Supply parasym. fibres to GI tract + abdo. organs up to distal end of transverse colon
What does the Pelvis splanchnic nerves supply?
Presynaptic parasym. nerve fibres supplying to smooth muscle/glands of the descending colon to anal canal
For the foregut, midgut and hindgut, where is pain usually felt?
Foregut - epigastric region
Midgut - umbilical region
Hindgut - pubic region
Where does the visceral afferent nerve fibres enter the spinal cord for the foregut, midgut and hindgut?
Foregut - approx. T6 - T9
Midgut - approx. T8 - T12
Hindgut - approx. T10 - L2