Anatomy Flashcards
What are the components of the GI tract?
Oral cavity, pharynx, oesophagus, stomach, small intestine, large intestine, accessory muscles, rectum, anal canal and anus
What joint is used to hinge the jaw to the skull?
temperomandibular joint
What muscles are associated with opening or closing of the Jaw?
3 pairs of closing muscles - messier, temporals and medial pterygoid
1 pair of opening - lateral pterygoid
which nerves supply opening and closing of the mouth?
CN V3
where does the CNV3 nerve enervate?
the muscles of mastication (chewing) and sensory areas
How are the teeth in an adult mouth described (location) and what does each number (1 to 8) correspond with?
upper right and left lower left and right
1-2 insisors, 3 canine, 4-5 premolars and 6-8 are wisdom teeth
Describe the sensation of the oral cavity
superior half of palate - CNV2 inferior half (floor of mouth) - CNV3
How is the tongue split up in terms of sensory nerves?
anterior two thirds = CN3 and CN7
posterior third = supplied by CN 9
what does CN7 supply?
anterior tongue for taste, muscles for facial expression and glands in floor of mouth
What does CN 9 innervate?
parotid gland and posterior aspect of tongue
What stimulates the gag reflex?
sensory = CN9 and motor is cranial nerve 9 and 10
How does local anaesthetic work on the back of throat?
block sensory action potentials = CN 5, 7 and 9
Detail the mechanism of swallowing
1) close lips to avoid drool
2) tongue pushes bolus of food towards oropharynx
3) inner layer of longitudinal muscles contracts to raise larynx, shorten pharynx and close of laryngeal inlet to prevent aspiration
4) bolus of food enters oesophagus and travel inferiorly by peristalsis
5) initiation of swallowing is voluntary and all the muscles are supplied by cranial nerves
What do the intrinsic muscles of the tongue do?
modify shape of tongue
What nerve innervates tongue? (except palatoglossus)
all supplied by CN 12 (hypoglassal)
What does CNV12 innervate?
extrinsic and intrinsic muscles of the tongue
What innervates the posterior pharynx?
Vagus nerve
What is the function of the longitudinal muscles of the pharynx?
elevate pharynx and larynx(close over laryngeal inlet)
contract to shorten pharynx
where does the oesophagus start?
where does it end?
inferior edge of cricopharynxgeus (vertebral level C6)
ends - cardia of the stomach
what are the sphincters involved in the oesophagus?
anatomical upper and physiological lower(helps reduce reflux, lies immediately superior to gusto-oesophageal junction)
What is the purpose of oesophageal plexus?
runs on surface to supply smooth muscle within its walls
What is the peritoneum
serous membrane, is in contact with the body wall and the organs
where is the peritoneal cavity located?
between the visceral and parietal layers
What are some intraperitoneal organs, retroperitoneal and organs with a mesentery
I = liver - covered in visceral peritoneum
R - pancreas and liver - visceral peritoneum on its anterior surface
mesentery - parts of intestines
Why are the intestines very mobile?
mesentery (double layer of visceral peritoneum) suspends the organ from the posterior abdominal wall
How do the omen divide in the peritoneal cavity?
greater sac and lesser sac - communicate through omental foramen
What pouches are formed in men and women?
one pouch in males = rectovesical
2 in females vesicouterine pouch and rectouterine pouch (pouch of Douglas)
What is ascitic fluid? - how is drained?
excess fluid within the peritoneal cavity - drained by a procedure called paracentesis
What is the small intestine made up of?
duodenum, jejunum and ileum
What is the large intestine made up of?
the colon - caecum, appendix, ascending colon, transverse colon, descending colon and sigmoid colon
The rectum
anal canal
anus
What embryological regions are the abdominal organs described to be within?
foregut (upper), midgut (leftish) and hindgut (far right going down to anus)
How do sympathetic nerves get from CNS to abdominal organs?
leave spinal cord between T5 and L2
enter sympathetic chain but do not synapse
leave as abdominopelvic splanchnic nerves
synapse at prevertebral ganglia
hitch a ride with other nerve fibres going towards smooth muscle and glands of the organs
What about adrenal gland as an exception to the sympathetic nerves?
leave spinal cord, enter abdominopelvic splanchnic nerves but do not synapse at prevertebral ganglia they synapse directly onto cells
How do parasympathetic nerves get to the abdominal organs?
enter on the surface of the oesophagus, travel into periarterial plexuses, carried to walls of organs where they synapse in ganglia
When are pelvic splanchnic neves used for para innervation?
smooth muscle or glands of depending colon to anal canal
How do visceral afferents get to the CNS form organs?
travel up the sympathetic chain foregut = T6 to T9 midgut = T8 to T12 hindgut = T10 to L2 pain form these organs tends to come depend on the location of the dermatome in relation to the entering of the visceral afferent
Where is pain felt in foregut, midgut and hindgut?
Epigastric, umbilical and pubic region
What is the alimentary canal?
series of hollow organs running form mouth to anus (oral to aboral) that are separated by sphincters
What are the four major functions of the alimentary canal?
motility - mechanical activity mostly involving smooth muscle
secretion - into the lumen of digestive tract in response to food, hormones or neural signals:
Digestion - chemical breakdown by enzymatic hydrolysis of complex foods into small absorbable units
absorption - transfer of absorbable products of digestion from digestive tract to the blood or lymph
what is the result of circular muscle contraction, longitudinal and muscularis mucosae contraction:
circular - lumen becomes narrower and longer
long - intestine becomes shorter and fatter
musculais - mixing activity
What organs are involved if a patient is jaundiced?
Liver, spleen, gallbladder, pancreas and small intestines
What is bilirubin
by-product of the breakdown of RBC
What is bilirubin used for?
used to form bile, which travels through the biliary tree
Why is the gall bladder important for bile?
It plays an important rile in the storage and concentration of bile
Why is bile important?
Used for the normal absorption of fats from the small intestine
What does the portal triad consist of?
three important tubes - hepatic artery(blood supply), hepatic vein(drainage) and the common bile duct (part of biliary tree)
What is the anatomy of the celiac trunk?
where is it found on a vertebral level?
When does it trifurcate?
First of the three midline branches of the abdominal aorta
T12 vertebral level
trifurcates into splenic artery, hepatic artery and left gastric artery
Describe the anatomical path of the splenic artery
where is the spleen found
Very tortuous course, intraperitoneal organ within the left hypochondrium
How is the spleen palpated clinically?(diaphragm)
Palpation is time with the persons breathing due to being anatomically linked to the diaphragm
Where does the blood supply from the stomach come from?
right and left gastric arteries - run along lesser curvature (anastomose together)
Right and left gastro-mental
run along greater curvature (anastomose together)
Where does the blood supply from the liver come from?
hepatic artery which branch into right and left hepatic arteries
75% is from portal vein in order to be cleared
What are the four anatomical segments of the liver?
Right lobe, left lobe, caudate lobe and quadrate lobe
How is the liver split up in terms of functional segments?
8 functional segments each with their own blood supply
Where does the liver drain?
via 3 main hepatic veins into the IVC
Why does hepatomegaly occur?
rise in central venous pressure is directly transmitted to the liver
In relation to the liver, what are the two man areas of the peritoneal cavity
What happens when patient is lying supine?
hepatorenal recess and sub-phrenic recess
when the patient is supine - the hepatorenal recess is one of the lowest parts of the peritoneal cavity
Describe the venous drainage of the liver in terms of the foregut
hepatic portal vein - drains blood from foregut, midgut and hindgut to the liver for first pass metabolism
splenic vein venous drainage?
drains the blood from the foregut
What does the inferior mesenteric vein do?
Drains the blood from the hindgut
inferior vena cava?
drains cleaned blood from the hepatic veins into the right atrium
How do you take a lobe of liver out?
cut off hepatic vein and remove lobe
What is the function of the gall bladder?
what is the purpose of a cystic duct?
To store and concentrate bile in-between meals
contains a cystic duct that bile can blow in and out of
What is the blood supply of the gall bladder?
via the cystic artery - branch of the right hepatic artery (75% of people)
Where can pain be present if a patient has gallstones?
early pain will be in the epigastric area
can also be present in the hypochondrium
What important structures need to be identified when carrying out a cholecystectomy
cystic duct and cystic artery
How is the biliary tree formed? (common hepatic duct then common bile duct)
Right and left hepatic ducts unite - common hepatic duct
the common hepatic duct then comes together with cystic duct to form the bile duct (common bile duct)
Where does the biliary tree drain into?
2nd part of the duodenum
What is the definition of being jaundiced? - how is it caused?
yellowing of sclera - whites of eyes (or skin)
caused by an increase in blood levels of bilirubin
What are the anatomical locations of the bile duct?
Descend posteriorly to the first part of the duodenum
How is the ampulla of vater formed?
Bile duct joins with main pancreatic duct to form the ampulla of vater
Where does the ampulla of vater drain into?
2nd part of duodenum through the major duodenal papilla
What is the sphincter involved with the ampulla of vater?
Smooth muscle sphincters - bile duct, pancreatic duct and the sphincter of Oddi
How can jaundice occur extra hepatically or post hepatically ? - how does this occur?
Blockage of biliary tree caused by gallstones, carcinoma at the head of pancreas (compresses duodenum)
Bile can flow back into the liver and overspill into the blood
What are the 4 different parts of the pancreas
Head (uncinate process), neck, body and tail
What surrounds the head of the pancreas?
duodenum
What are the two functions of pancreas?
Exocrine - acinar cell (pancreatic digestive enzymes into main pancreatic duct)
endocrine - islets of langerhans and secrete insulin and glucagon
What arteries supply the pancreas?
branches from splenic artery
gastroduodenal artery - superior pancreaticoduodenal
Superior mesenteric artery - inferior pancreaticoduodenal
If there is a blockage of the ampulla where can the pain be felt?
Foregut and midgut organ so pain is felt in epi or umbilical region
but can also radiate to the back
How can the small intestine be split up into embryological origins?
1st and second part of the duodenum are foregut organs
the rest are midgut
What is the anatomy of the small intestine?
4 parts - superior, descending, horizontal and ascending
begins at pyloric sphincter
How is the small intestine supplied with blood?
gastroduodenal artery - superior pancreaticoduodenal
Superior mesenteric artery - inferior pancreaticoduodenal
How do you differentiate between the 3 different types of small intestine?
found in all 4 quadrants
jejunum begins at duodenaljejunal flexure
ileum ends at ileocaecal junction
What are the different types of mucosa int he jejunum and ileum?
mucosa of jejunum = plicae circulares - loads of like little folds
distal ileum is much smoother
Describe the blood supply and drainage to the ileum and the jejunum
arterial blood - superior mesenteric artery (jejunal and ileal arteries)
Venous drainage - jejunal and ileal veins, to superior mesenteric vein and hepatic portal vein
Describe the process of fat absorption
bile is used to help intestinal cells absorb fats
lacteals( pick up the fats) travel via the lymphatic system to eventually drain into the venous system at the left venous angle
What are the main groups of lymph nodes draining abdominal organs?
celiac(foregut), superior mesenteric(midgut), inferior mesenteric(hindgut) and lumbar (everything else)
Detail the lymph drainage of the human body
superficial vessels drain into deep lymph vessels -
drain into thoracic duct or the right lymphatic duct (venous angles)
eventually drain into venous system to be recycled
What parts of the colon are mobile?
start of the colon(caecum) - intraperitoneal
transverse colon - intraperitoneal
sigmoid colon - intraperitoneal
Where are the paracolic gutters found?
2 of them - found between lateral edge of ascending and descending wall
part of greater sac of peritoneal cavity
What is the risk involved in paracolic gutters?
potential sites for pus collection
what are haustra?
segmented pouches formed by tonic conctractions of teniae coli
What are teniae coli?
3 distinct longitudinal bands of thickened smooth muscle running from the caecum to the distal end of the sigmoid colon
How can faeces been seen on a radiograph
Distinct mottled (marked with spots) appearance
Where the caecum and apprendix found?
both lie in the right ileac fossa - appendix is most often retrocaecal
What is the McBurney point?
Why is it important in appendicitis?
Appendiceal orifice on posteromedial wall of caecum -
in theory this is the area of maximum tenderness in appendicitis
Where is the sigmoid colon found?
left iliac fossa
What does the sigmoid colon have?
long mesentery (sigmoid mesocolon) - gives rise to a considerable degree of movement
Why in a clinical scenario is the movement of the sigmoid colon bad?
at risk of twisting around itself - sigmoid vovulus (at risk of ischaemia)
What are the three midline branches of the aorta?
Celiac trunk - foregut
superior mesenteric artery - midgut
inferior mesenteric artery - hidngut
What do the lateral branches of the abdominal aorta supply?
kidneys/ adrenal glands, gonads and body wall - abdominal aorta eventually bifurcates into common iliacs
What organs are in the fore gut?
oesophagus to mid duodenum
liver, gall bladder, spleen and half of pancreas
What organs are in the midgut?
mid-duodenum to 2/3rds of transverse colon
1/2 of pancreas
What organs are in the hindgut?
Distal 1/3rd of transverse colon to proximal 1/2 of anal canal
What is an important arterial anastamoses in the GI tract?
between branches of SMA and IMA - predominantly one artery called the artery of Drummond
What supplies the remainder of the GI tract after the proximal 1/2 of the anal canal?
supplied by internal iliac artery
What is haematemesis? and how could a peptic ulcer cause this?
vomiting up blood
peptic ulcer erodes through mucosa and stomach/duodenum fills with blood
How can oesophageal varices cause bleeding?
abnormally dilated veins are thing and susceptible to bursting so causing bleeding
What is the body’s two main venous systems?
hepatic portal vein -drain blood from the GI tract to be cleaned by the liver (absorptive parts)
systemic venous system - takes blood from everywhere else straight into the inferior vena cava
What does the inferior vena cava do?
drains cleaned blood from the hepatic veins into the right atrium
Hepatic vein?
Drains blood from foregut, hindgut and mid gut organs to the liver for first pass metabolism
Splenic vein?
drains blood form foregut structures to hepatic portal vein
superior mesenteric vein
drains blood from midgut structures to hepatic portal vein
inferior mesenteric vein
drains blood from hindgut structures to splenic vein
Where are the three clinically important sites for venous anastamoses? (blood can flow in either directions due to the presence of small collateral veins (no valves))
Distal end of oesophagus (superior goes to azygous vein)
skin around umbilicus (superior goes to portal)
rectum/anal canal (inferior goes to internal ileac vein)
What is portal hypertension?
raised blood pressure in the portal venous system - blood is diverted through collateral veins into system circulation
Where are the three sites of portal hypertension?
oesophageal varices, caput medusae (umbilicus) and rectal varices
What does the superior mesenteric vein do?
Drains blood from the midgut
What are some factors that need to be in place for faecal continence
Holding area, normal visceral afferent nerve fibres, function muscle spincters, normal cerebral function
What is the pelvic floor?
Contains an opening to allow ailemntary, ranl and reproductive tractd to pass
What is the pelvic floor made up of?
levator ani - + roof of perineum
number of small muscles - iliococcygeus
pubococcygeus and puborectalis
all skeletal muscles!
Why are the levator ani muscles tonically contracting?
To provide support to the abdominal organs and prevent prolapse
What are the nerves that supply levator ani
nerve to levator ani and pudendal
WHen does sigmoid become rectum?
anterior to S3 (rectosigmoid junction)
When does the rectum become the anal canal?
anterior to tip of coccyx
WHere is the rectum, anal canal and anus found?
rectum - pelvis
anal canal and anus - perineum
What is the rectal ampulla?
lies just above levator ani muscle
functioning muscle and muscle sphincer ………..
What is the rectal ampulla?
lies just above levator ani muscle
functioning muscle and muscle sphincer ………..
What are some anatomical relationships of the rectum
peritoneum coveres superior rectum
rectouterine/ rectovesical pouch lie anterior to the superior rectum
Why is a puborectais muscle important?
contraction of this muscle decreases anorectal angle, acting like a sphincter
voluntary contraction of this msucle will help to maintian continence
S2 S3 S4 keeps the rectum off the floor - which nevre is this?
Peudental nerve - anterior rami
supplies external anal sphincter
branches to supply structures of perineum
What are teh key differences between internal and external spincters?
internal
contracted all the time, relaxes reflexively in response to distension (filling) of the rectal ampulla
External - voluntary contracted (along with puborectalis msucle) in response to rectal ampulla distention in internal sphincter relaxation
Why is the location of the pelvis/perineum important in the nerve supply?
Fundamental to deciding what nerve type carries out what function…
Detail the nerve supply to the rectum/ anal canal
Visceral affents back to S2-S4; run with parasympathetics - sense stretch, ischaemia etc
sympathetic fibres form T12-L2 travel to inferior mesenteric ganglia, synapse, then travel via periarterial plexuses around branches of IMA - contraction of internal anal sphincter and inhibit peristalsis
para sympathetic nerves from S2-S4 via pelvic splanchnic nerves synapse in walls of rectum - inhibit internal anal spnicter and stimulate peristalisis
Somatic motor form pudendal nerve (S2-S4) and nerve to levator ani (S3,S4) - contraction of external anal spincter and puborectalis
What can happen during labour that damages pudendal nerve/ sphincter?
Branches of the nerve can be stretched
fibres within puborectalis or external anal sphincter could be torn
faecal incontinence could result
What is the ischioanal fossa?
What can spread easily?
Lie on each side of the anal canal
filled with fat and loose connective tissue
can communicate with eachother - abbcess can spread easily due to only fat and connective tissue being present
What is the blood supply to the rectum and anal canal?
IMA - hindgut
remainder is internal iliac artery - degree of anastamoses between the vessels
Venous =
Inferior mesenteric vein drains the hindgut organs - above petinate line, portal veous system
internal iliac veins drains below pectinate line to the portal venous system
What is the difference between rectal varicies and haemorrhoids
rectal varicies = relation to portal hypertension
haemorrhoids - prolapses of rectal venous plexuses (raised pressure)
What is a PR exam good for?
to assess anal tone
What is in the right upper quadrant?
Liver, gall bladder & biliary tree
Duodenum (1st, 2nd, 3rd parts), Pancreatic head
Colon (hepatic flexure, AC, TC)
Right kidney/adrenal gland
What is in the left upper quadrant?
Spleen Stomach, Small Bowel Pancreatic tail Colon (splenic flexure, DC, TC) Left kidney/adrenal gland
Why are ruage important?
WHat are the curvatures of the stomach? - what is suspended on it?
Rugae increase surface area of stomach
Lesser curve forms right border, suspended on lesser omentum
Greater curve forms left border, greater omentum suspended from it
What is the blood supply of the stomach like?
Arterial supply from branches of the COELIAC AXIS
Venous drainge via tributaries to the SMV and PORTAL VEIN
Where does the small bowel start and end?
LIGAMENT of TREIZ to ILEOCAECAL VALVE
What is the small bowel suspended on?
Detail the differences in mesenteric attachment in jejunum and ileum
Suspended on a MESENTERY
The mesentery of jejunum is attached to the left of aorta while the mesentery of ileum is attached to the right
‘arcades’ of vessels run in the mesentery to supply & drain the small bowel
What does the terminal ileum do?
The terminal ileum conveys liquid waste to the caecum
The terminal ileum also reabsorbs bile salts for recycling by the liver.
What is the blood supply like in the spleen?
Arterial Supply from SPLENIC ARTERY
Venous drainage via SPLENIC VEIN to PORTAL VEIN
What lies in the RIF?
Caecum/terminal ileum
Appendix
Right Ureter (ovary/fallopian tube/uterus)
Bladder
What does the LIF contain?
Sigmoid colon
Left Ureter (ovary/fallopian tube/uterus)
Bladder
What does the colon contain?
What does it exhibit?
It stores gas and faeces, making it visible on an x-ray
Exhibits HAUSTRA
Detail the parts of the colon-
From proximal to distal, caecum, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon and rectum
Whtt does the rectum do?
Where does it lie? In relation to males and females
The RECTUM stores faeces prior to defaecation via the anal canal
It lies anterior to the SACRUM/COCCYX and posterior to the
VAGINA in females
PROSTATE & SEMINAL vesicles in males
What is retroperioneal and intraperitoneal
Caecum = INTRAPERITONEAL
Ascending and Descending colon = RETROPERITONEAL
Transverse colon = INTRAPERITONEAL, suspended on a mesentery
Sigmoid colon = INTRAPERITONEAL, suspended on a mesentery
Rectum = upper 2/3 covered by peritoneum, lower 1/3 isn’t
What are the different parts of the peritnoeum? (retro, intra - why can intra move about?
objects that are only just covered are ‘retroperitoneal’
those that are completely wrapped up are ‘intraperitoneal’
intraperitoneal objects that can move because behind them, the cling film has stuck to itself have a ‘mesentery’
What is the blood supply to the colon?
SUPERIOR MESENTERIC ARTERY forms MIDDLE COLIC(transverse colon), RIGHT COLIC and ILEOCOLIC ARTERIES
Supply CAECUM, ASCENDING and PROXIMAL TRANSVERSE colon
INFERIOR MESENTERIC ARTERY forms LEFT COLIC, SIGMOID and SUPEIOR RECTAL ARTERIES
Supply DISTAL TRANSVERSE, DECENDING, SIGMOID COLON and UPPER RECTUM
What all forms into the portal vein?
Superior mesenteric + splenic vein, gastric + part form inferior mesenteric
Describe the hepatic blood flow
oxygenated blood from hepatic artery and nutrient rich -deoxygenated blood from hepatic portal vein
liver sinusoids
central vein
hapatic vein
inferior vena cava
right atrium of the heart
Why is portal hypertension worse in cirrhosis?
resistance to outflow but a dramatically increased inflow into the portal circulation
What are the causes of portal hypertension?
Prehepatic - blockage of protein vein before liver - thrombosis or occlusion secondary to congenital portal venous abnormalities
Intrahepatic - distortion of the liver architecture
Budd chair syndrome and veno-occlusive disease
What is herniation
Any structure passes through another and ends up in the wrong place
What are the 2 things required for hernias to occur?
structural weakness (normal - diaphragmatic, umbilicus) (abnormal - congenital (diaphragmatic hernia, surgical scar - incisional hernia)
Increased pressure - chronic cough, pregnant, strenuous activity
What does the lineas semilunar separate?
Anterior and lateral abdominal wall
What does the linea alba meet?
anterolateral abdominal wall muscles
Why is the inguinal region important anatomically and clinically
Passage into and out of abdomen
clinical - Potential for passages to have weakness that can lead to herniation
Which way do the external oblique muscles run?
Internal oblique and transverses abdominis muscle
(hand in pockets - anteroinferior)
(hands on chest - anterosuperior fibre direction)
Transversus abdominus muscle - horizontal fibres
What marks the anterior boundary between the abdomen and the thigh?
Inguinal ligament
How is the inguinal ligament formed?
Inferior thickening of the external oblique
What is the 4cm long passageway through the anterior abdominal wall in the inguinal regions?
Inguinal canal
What surrounds each inguinal canal?
Deep ring and a superficial ring
What is the gubernaculum?
connects inferior pole of gonads to the peritoneum
In the dropping of the testis why is the vaginal process important?
Protrudes the other layers of the body down with the decent of the gonads
What is the hesselbach’s triangle?
What are the structures that form the triangle?
site of direct inguinal herniation
inguinal ligament
inferior epigastric artery
Lateral border fo the rectus abdomens
Deep inguinal ring
Site of indirect inguinal herniation
What is the definition of a direct inguinal hernia?
Does it occur medially to the epigastric artery?
What is it parallel to?
Directly through abdominal wall
Yes
Spermatic cord
What does indirect hernia use for herniation?
What is it lateral to?
What is it within?
Inguinal canal
Lateral to inferior epigastric artery
Within spermatic cord or layers of abdominal wall
Where does femoral herniation occur?
Through the femoral canal which is medial to the vessels (artery and veins)
Where is the myopectineal orifice?
Whole area of innate weakness at the inguinal ligament
On the body - where is the deep inguinal ring and the superficial inguinal ring?
deep - superior to the Half way point along the inguinal ligament
Superficial - superior and lateral to the pubic tubercle
