GI anatomy - Full summary Flashcards
1
Q
What joint allows opening and closure of the mouth?
A
Temperomandibular joint
2
Q
What bones are involved in the temperomandibular joint?
A
Temporal bone
Mandible
3
Q
How many muscles of mastication are there?
A
4
4
Q
How many muscles open the jaw?
A
1
5
Q
How many muscles close the jaw?
A
3
6
Q
Which muscle opens the jaw?
A
Lateral pterygoid muscle
7
Q
What are the 3 muscles that open the mouth?
A
Masseter
Temporalis
Medial pterygoid
8
Q
Where can the masseter be palpated?
A
At the corner of the jaw when the jaw is clenched
9
Q
Where can the temporals be palpated?
A
At the pterion of the skull when the jaw is clenched
10
Q
Which nerve supplies the muscles of mastication?
A
The mandibular branch of the trigeminal nerve (CN V3)
11
Q
Describe the structure of the temperomandibular joint
A
12
Q
What occurs in dislocation of the jaw?
A
The head of the condylar (Posterior) process of the mandible moves out of the mandibular fossa and moves infant of the articular tubercle of the temporal bone and becomes lodged
13
Q
Where does the oral cavity start?
A
Behind the teeth
14
Q
What are the 2 forms of palate in the oral cavity?
A
Hard palate - Palatine bones
Soft palate - Soft tissue
15
Q
What is the uvula?
A
The ending of the soft palate that dangles down into the throat
16
Q
What are the 2 arches in the oral cavity?
A
Palatoglossal arch - Anterior arch
Palatopharyngeal arch - Posterior arch
17
Q
Where are the palatine tonsils found?
A
Either side of the oral cavity, posterior to the arches
18
Q
What is the name given to the space between the teeth and lips?
A
The vestibule
19
Q
What connects the lips and the gingiva (Gums)?
A
The upper and lower labial frenula
20
Q
What is the name given to the cheek tissue?
A
Buccal tissue
21
Q
What is the average number of teeth in an adult human?
A
32
22
Q
What is the average age by which all teeth, including wisdom teeth, should have erupted?
A
18 (If wisdom teeth don’t erupt by 25, presume that they won’t)
23
Q
What are the 4 quadrants of the dentition?
A
Upper left
Upper right
Lower left
Lower right
24
Q
How many teeth are found in the average human quadrant?
A
8
25
Which numbered teeth in a quadrant are incisors?
1 and 2
26
Which numbered tooth in a quadrant is a canine?
3
27
Which numbered teeth in a quadrant are pre-molars?
4 and 5
28
Which numbered teeth in a quadrant are molars?
6, 7 and 8
(8 = Wisdom tooth)
29
What is the name given to the space behind the wisdom teeth?
Retromolar trigone
30
What are the 3 types of salivary glands?
Parotid
Sub-mandibular
Sub-lingual
31
Where does the parotid gland empty into?
The papillae in the upper buccal wall on each side of the vestibule, behind the 2nd upper molars
32
Where do the submandibular glands empty to?
The frenulum of the tongue
33
Where do the sub-lingual glands empty to?
The floor of the mouth
34
What is the name of cranial nerve I and what type of nerves does it supply?
Olfactory - Sensory
35
What is the name of cranial nerve II and what type of nerves does it supply?
Optic - Sensory
36
What is the name of cranial nerve III and what type of nerves does it supply?
Occulomotor - Motor
37
What is the name of cranial nerve IV and what type of nerves does it supply?
Trochlear - Motor
38
What is the name of cranial nerve V and what type of nerves does it supply?
Trigeminal (V1,2 & 3) - Both sensory and motor
39
What is the name of cranial nerve VI and what type of nerves does it supply?
Abducens - Motor
40
What is the name of cranial nerve VII and what type of nerves does it supply?
Facial - Both sensory and motor
41
What is the name of cranial nerve VIII and what type of nerves does it supply?
Vestibulocochlear - Sensory
42
What is the name of cranial nerve IX and what type of nerves does it supply?
Glossopharyngeal - Both sensory and motor
43
What is the name of cranial nerve X and what type of nerves does it supply?
Vagus - Both sensory and motor
44
What is the name of cranial nerve XI and what type of nerves does it supply?
Spinal accessory - Motor
45
What is the name of cranial nerve XII and what type of nerves does it supply?
Hypoglossal - Motor
46
What are the functions of cranial nerve V3 (Trigeminal 3) in the upper GI tract?
Supplies general sensation to lower oral cavity
Gives general sensation to anterior tongue
Gives motor sensations to jaw muscles
Supplies sublingual salivary glands (With chord timpani of VII)
47
What are the functions of cranial nerve V2 (Trigeminal 2) in the upper GI tract?
Gives general sensation to the upper half of the oral cavity
Gives general sensation to middle face
48
What are the functions of cranial nerve IX (Glossopharyngeal ) in the upper GI tract?
Supplies posterior oropharynx with motor and sensory (Gag reflex)
Supplies general and special sensory to posterior tongue
Supplies secretomotor innervation to parotid gland
49
What are the functions of cranial nerve X (Vagus) in the upper GI tract?
Supplies posterior oropharynx with motor nerves (Gag reflex)
Allows contraction of pharynx
50
What are the functions of cranial nerve VII (Facial) in the upper GI tract?
Supplies special sensory (Taste) to anterior tongue
Supplies sub-lingual salivary gland (Chordae timpani branch)
51
What are the functions of cranial nerve XII (Hypoglossal) in the upper GI tract?
Supplies motor innervation to the tongue muscles (Not palatoglossus)
52
Describe the route of cranial nerve V2 (Trigeminal 2)?
From pons
Through foramen rotunda
To mid-face and upper jaw
53
Describe the route of cranial nerve V3 (Trigeminal 3)?
From pons
Through foramen ovale
To muscles of mastication and inferior oral cavity
54
Describe the route of cranial nerve VII (Facial)?
From pontomedullary junction
Through internal acoustic meatus
Branches (to form chordae timpani, which joins V3 to supply sub-lingual glands)
Through stylomastoid foramen
To anterior tongue, facial expression muscles and glands in mouth floor
55
Describe the route of cranial nerve IX (Glossopharyngeal)?
From medulla
Through jugular foramen
To posterior oropharynx, parotid gland and posterior tongue
56
Describe the route of cranial nerve XII (Hypoglossal)?
From medulla
Through hypoglossal canal
To muscles of tongue (Except palatoglossus)
57
How does the gag reflex occur?
Contact with posterior oropharynx stimulates cranial nerve IX (Glossopharyngeal)
This stimulates motor nerves of cranial nerves IX and X (Glossopharyngeal and Vagus)
This elevates the pharynx and larynx, shortening the pharynx and closing the laryngeal inlet
58
How many muscles cause movement of the tongue?
8 pairs of muscles (16 muscles total)
59
How many pairs of extrinsic muscles control the tongue?
4
60
How many pairs of intrinsic muscles control the tongue?
4
61
What are the 4 pairs of extrinsic muscles that control the tongue?
Palatoglossus (Palate to tongue)
Styloglossus (Styloid process to tongue)
Hyoglossus (Hyoid to tongue)
Genioglossus (Genial tubercles of mandible to tongue)
62
What do the intrinsic muscles of the tongue change?
The shape of the tongue
63
What do the extrinsic muscles of the tongue change?
The position of the tongue
64
What are the 3 layers of circular constrictor muscles of the pharynx?
Superior constrictor
Medial constrictor
Inferior constrictor
65
Why can swallowing only go one way?
The circular constrictor muscles contract sequentially and so only contract to push food down
66
Which cranial nerve innervates the circular muscles of the pharynx?
Cranial nerve X (Vagus)
67
What muscle forms the end of the pharynx and the inlet to the oesophagus?
Cricopharyngeus muscle
68
What is the function of the inner layer of longitudinal muscles in the pharynx?
They elevate the pharynx and larynx, shortening the pharynx and closing the laryngeal inlet
69
Which nerve supplies the inner layer of longitudinal muscles in the pharynx?
Cranial nerves X and IX (Vagus and glossopharyngeal)
70
What happens to the oesophagus when nothing is passing down it?
It closes
71
What type of sphincter is the upper oesophageal sphincter?
Anatomical sphincter
72
What type of sphincter is the lower oesophageal sphincter?
Physiological sphincter
73
What forms the upper oesophageal sphincter?
The cricopharyngeus muscle
74
What causes the formation of the lower oesophageal sphincter?
Contraction of the diaphragm
Intra-abdominal pressure being higher than intra-gastric pressure
Oblique angle at which the oesophagus enters the cardia
75
What are the 3 main constrictions of the oesophagus?
Cervical constriction - Cricopharyngeus
Thoracic constriction - Arch of aorta and left main bronchus
Diaphragmatic constriction - Lower oesophageal sphincter
76
What is the function of the oesophageal nerve plexus that runs along its surface?
It innervates the smooth muscle with both types of autonomic supply, allowing for acceleration and deceleration of peristalsis
77
What is the name given to the top right region of the abdomen?
Right hypochondrium
78
What is the name given to the top left region of the abdomen?
Left hypochondrium
79
What is the name given to the upper middle region of the abdomen?
Epigastric region
80
What is the name given to the middle left region of the abdomen?
Left lumbar (Flank)
81
What is the name given to the middle right region of the abdomen?
Right lumbar (Flank)
82
What is the name given to the central region of the abdomen?
Umbilicus
83
What is the name given to the middle left region of the abdomen?
Left lumbar (Flank)
84
What is the name given to the lower right region of the abdomen?
Right iliac fossa (Inguinal)
85
What is the name given to the lower middle region of the abdomen?
Surpapubic (Pubic)
86
What is the name given to the lower left region of the abdomen?
Left iliac fossa (Inguinal)
87
How can the abdomen be split into 4 regions?
Upper left quadrant
Upper right quadrant
Lower left quadrant
Lower right quadrant
These are in the median plane and trans-umbilical plane
88
What is the name of the anterior muscle of the abdomen?
Rectus abdominus
89
What are the 3 muscles of the anterolateral chest wall?
External oblique - Most superficial
Internal oblique
Transversus abdominus - Most deep
90
What are the semicircular lines formed at the divide between muscle and aponeurosis known as?
Linea semilunaris
91
What is the name of the fascia at the division between muscle and aponeurosis of the abdomen?
Spigalean fascia
92
What is the rectus sheath?
The sheath that surrounds the rectus abdominus, formed from the joining of bilateral aponeuroses
93
What is the name of the line formed down the midline, formed by the joining of bilateral aponeuroses?
Linea alba
94
Which layers of aponeuroses form the posterior wall of the rectus sheath?
Transversus abdominus
Posterior half of inner oblique
95
Which layers of aponeuroses form the anterior wall of the rectus sheath?
Outer oblique
Anterior half of inner oblique
96
Where are some common points of herniation in the abdominal wall?
Linea alba
Linea semilunari
Inguinal canal
97
What is formed as the rectus sheath moves inferiorly?
The inguinal ligament
98
Where does the inguinal ligament attach to the skeleton?
At the pubic tubercle
99
What boundary is marked by the inguinal ligament?
The boundary between the thigh and the abdomen
100
What is found beneath the inguinal ligament?
The inguinal space contains many important structures
101
What is the inguinal canal made up of?
The inguinal ligament and body wall
102
What is the function of the inguinal canal?
It allows the movement of the testes down from the posterior abdominal wall into the scrotum during development
103
Who has an inguinal canal?
Both males and females
104
What is the entrance (abdominal) to the inguinal canal called?
The deep ring
105
What is the exit (Testicular) of theinguinal canal called?
Superficial ring
106
Describe the anatomical location of the deep ring
It is located superior to the midpoint of the inguinal ligament
107
Describe the anatomical location of the superficial ring?
This lies super-lateral to the pubic tubercle
108
What structure forms the floor of the inguinal canal?
The medial half of the inguinal ligament
109
What structure guides the testes down through the abdominal wall?
The gubernaculum, a string like structure
110
What is the name given to the space with which the testes descend?
The vaginal process (Processes vaginalis)
111
What is the function of the vaginal process (Processus vaginalis)?
It reduces friction on the testicle as it descends
112
What becomes of the gubernaculum in males?
It forms the spermatic cord (Testicular ligament)
113
What is contained in the spermatic cord?
Testicular artery
Vas deferens
Pampiniform plexus of veins
113
What is contained in the spermatic cord?
Testicular artery
Vas deferens
Pampiniform plexus of veins
114
What becomes of the gubernaculum in females?
It forms the round ligament of the uterus
115
What happens to the layers of the body wall as the testicles descend?
The layers move with it forming some important structures of the scrotum
116
How are organs of the abdomen classified?
By their embryological origin
117
What are the 3 classifications of abdominal organs?
Foregut
Midgut
Hindgut
118
What structures are found in the foregut?
Oesophagus
Stomach
Liver
Gallbladder
Spleen
Medial 1/2 pancreas
Proximal 1/2 duodenum
119
What structures are found in the midgut?
Distal 1/2 duodenum
Lateral 1/2 pancreas
Jejunum
Ileum
Caecum
Appendix
Proximal 2/3rd transverse colon
120
What structures are found in the hindgut?
Distal 1/3 transverse colon
Descending colon
Sigmoid colon
Rectum
Proximal 1/2 anal canal
121
What are the 3 midline branches of the abdominal aorta?
Coeliac trunk
Superior mesenteric artery
Inferior mesenteric artery
122
What structures are supplied by the lateral branches of the abdominal aorta?
Kidneys (Renal artery)
Gonads:
Testicles (Testicular artery)
Ovaries (Ovarian artery)
Body wall
123
At what level does the abdominal aorta bifurcate?
L4
124
At what levels does the coeliac trunk exit the abdominal aorta?
T12
125
Is the coeliac trunk retro or intra-peritoneal?
Retroperitoneal
126
What are the 3 initial branches of the coeliac trunk?
Splenic artery
Hepatic artery
Left gastric artery
127
Describe the course of the splenic artery
The splenic artery has a tortuous course across the superior border of the pancreas and posterior surface of the stomach
128
What organs are supplied by the splenic artery and its branches?
Spleen
Stomach
Pancreas
129
What branches of the splenic artery supply the stomach?
Short gastric artery
Posterior gastric artery
Left gastro-mental artery
130
What branches of the splenic artery supply the pancreas?
Pancreatic arteries
131
What artery does the left gastro-momental artery anastomose with and where?
It anastomoses with the right gastro-momental on the inferior surface of the stomach
132
What organs are supplied by the hepatic artery?
Liver
Gallbladder
Pancreas
Stomach
Duodenum
133
What branches of the hepatic artery supply the liver?
The hepatic artery proper, which bifurcates into the left and right hepatic artery
134
What are the 5, 1st line branches of the hepatic artery?
Right hepatic artery
Left hepatic artery
Right gastric artery
Gastroduodenal artery
Supraduodenal artery
135
What are the 2, 2nd line branches of the gastroduodenal artery?
Right gastro-ommental artery
Superior pancreaticoduodenal artery
136
What are the 2 main branches of the superior pancreaticoduodenal artery?
Posterior superior pancreaticoduodenal artery
Anterior superior pancreaticoduodenal artery
137
What artery does the left gastric artery anastomose with and where?
With the right gastric artery on the superior surface of the stomach
138
At what level does the superior mesenteric artery leave the abdominal aorta
L1
139
What are the 7 main branches of the superior mesenteric artery?
Inferior pancreatic duodenal
Middle colic artery
Right colic artery
Ileocolic artery
Jejunal arteries
Ileal arteries
Appendicular artery
140
What are the 2 main branches of the inferior pancreaticoduodenal arteries?
Anterior inferior pancreaticoduodenal
Posterior inferior pancreaticoduodenal
141
What structures are formed by the arteries of the superior and inferior mesenteric arteries?
Arterial arcades (Loops)
142
What is the name of the arteries that connect the arterial arcades to the intestinal wall?
Vasa recta
143
At what level does the inferior mesenteric artery leave the abdominal aorta?
L3
144
What are the 3 main branches of the inferior mesenteric artery?
Left colic
Sigmoid colic
Superior rectal
145
What is the name of the artery that anastomoses the branches of the superior and inferior mesenteric arteries?
Marginal artery of Drummond
146
What is the name of the line in the anal canal that marks the division between viscera and soma?
Pectinate line
147
What artery supplies structures of the anal canal superior to the pectinate line?
Superior rectal artery of the inferior mesenteric artery
148
What arteries supply the structures of the anal canal inferior to the pectinate line?
Middle and inferior rectal arteries of the internal ileac artery
149
What is haematemesis?
Presence of blood in the vomitus
150
What are the 2 venous systems of the body?
Hepatic portal system
Systemic venous system
151
What are the 3 main veins of the GI tract that form the hepatic portal vein?
Splenic vein
Superior mesenteric vein
Inferior mesenteric vein
152
Where does the inferior mesenteric vein drain into?
Splenic vein
153
Where does the superior mesenteric vein drain into?
Hepatic portal vein
154
Where does the splenic vein drain into?
Hepatic portal vein
155
Where does the hepatic portal vein drain into?
Liver
156
What vein drains blood form the hepatic veins of the liver to the heart?
Inferior vena cava
157
Where are the 3 portal systemic anastomoses?
Distal end of oesophagus
Skin around umbilicus
Rectum and anal canal
158
What is meant by a portal systemic anastamosis?
These are clinically important sites of anastomoses, containing collateral veins with no valves, meaning blood can flow either way
159
Where does blood from the superior part of the distal oesophageal portal systemic anastomosis drain into?
Azygous vein
160
Where does blood from the inferior part of the distal oesophageal portal systemic anastomosis drain into?
Left gastric vein and then the hepatic portal vein
161
Where does blood from the superior part of the rectal portal systemic anastomosis drain into?
Inferior mesenteric vein
162
Where does blood from the inferior part of the rectal portal systemic anastomosis drain into?
Internal iliac vein
163
What happens to the portal systemic anastomoses in portal hypertension?
As there are no valves, blood will be forced into them and back into systemic circulation
This is cause dilatation and they will become varicose
164
What is the name given to varicose veins around the umbilicus?
Caput medusae
165
What are the 3 variceal consequences of portal hypertension?
Oesophageal varices
Caput medusae
Rectal varices
166
What is jaundice?
This is a condition caused by a build up of bilirubin in the body, resulting in yellowing of the skin and eyes
167
What is bilirubin?
Bilirubin is a normal by-product of the breakdown of red blood cells by the spleen and is a constituent of bile
168
What are the 3 structures of the portal triad?
Hepatic artery
Hepatic portal vein
Common bile duct
169
In what quadrant is the liver mostly found?
Upper right quadrant
170
Describe the relation of the liver to the diaphragm?
The diaphragm lies superiorly, anteriorly and posteriorly to the liver
171
Describe the relation of the liver to the gallbladder?
The gallbladder lies posteriorly and inferiorly to the liver
172
Which ribs protect the liver?
Ribs 7-11
173
What are the 4 anatomical lobes of the liver?
Right lobe
Left lobe
Caudate lobe
Quadrate lobe
174
Where are the caudate and quadrate lobe of the liver found?
They are found on the inferior surface of the liver
175
Which lobe (Caudate or quadrate) is found more anteriorly and lies next to the gallbladder?
Quadrate lobe
176
What is the name given to the ligament that runs across the superior border of the right liver lobe?
Right coronary ligament
177
What is the name given to the ligament that runs across the superior border of the left liver lobe?
Left coronary ligament
178
What is the name given to the ligament that runs in the divide between the left and right lobes?
Falsiform ligament
179
What is the name of the embryological ligament that hangs inferiorly from the falciform ligament?
Ligamentum teres (Round ligament)
180
What embryological structure forms the ligamentum teres (Round ligament)?
Umbilical vein
181
How many functional segments of the liver are there?
8
182
How many main hepatic veins are there?
3
183
What feature of veins do the hepatic veins and IVC lack?
Valves
184
What are the 2 important recesses relating to the liver?
Sub-phrenic recess
Hepatorenal recess (Morrison's pouch)
185
Where is the sub-phrenic recess found?
Between the anterior diaphragm and the liver
186
Where is the hepatorenal recess (Morrison's pouch) found?
Between the right kidneys and liver posteriorly
187
In which sac of the peritoneal cavity are the sub-phrenic recess and hepatorenal recess found?
The greater sac
188
What is clinically important about the hepatorenal recess (Morrison's pouch)?
It is one of the lowest points of the peritoneal cavity when a patient is supine
189
Via which duct does bile enter and leave the gallbladder?
Cystic duct
190
What causes the gallbladder to contract?
Cholecystokinin (CCK) and parasympathetic stimulation
191
What artery carries blood to the gallbladder?
Cystic artery
192
Which artery branches to form the cystic artery in 75% of people?
Hepatic artery
193
How does bile move through the liver?
Via inter-hepatic ducts
194
Describe the path of bile from the liver to the gallbladder
Inter-hepatic ducts =>
Left and right hepatic ducts =>
Common hepatic duct =>
Cystic duct =>
Gallbladder
195
Describe the path of bile from the gallbladder to the duodenum
Cystic duct =>
Common bile duct =>
Ampulla of vater =>
Major Duodenal papilla =>
Duodenum
196
What 2 structures join to form the common bile duct?
Cystic duct
Common hepatic duct
197
What is the ampulla of vater?
The joining of the pancreatic duct and the common bile duct
198
Where is the major duodenal papilla?
In the 2nd part (Descending) duodenum
199
What are the 3 smooth muscle sphincters of the ampulla of vater?
Bile duct sphincter
Pancreatic duct sphincter
Sphincter of Odd
200
Is the pancreas retro or intra-peritoneal?
Retroperitoneal
201
What are the 4 main regions of the pancreas?
Head
Neck
Body
Tail
202
What is the process of the head of the pancreas called?
Uncinate process
203
Describe the position of the stomach in relation to the pancreas
The stomach is found anterior to the pancreas
204
What nerve provides the pancreas with parasympathetic innervation?
Vagus nerve
205
What nerves supply the pancreas with sympathetic innervation?
Abdominopelvic splanchnic nerves
206
What are the 3 regions of the small intestine?
Duodenum
Jejunum
Ileum
207
What are the 4 regions of the duodenum?
Superior
Descending
Horizontal/inferior
Ascending
208
At what structure does the duodenum begin?
At the duodenal cap at the pyloric sphincter
209
At what structure does the duodenum end?
Duodenojejunal flexure
210
What effect does parasympathetic stimulation have on the pyloric sphincter?
Relaxation - Opening
211
at effect does sympathetic stimulation have on the pyloric sphincter?
Contraction - Closing
212
Where will pain from a duodenal ulcer be felt?
IN the epigastric region
213
What artery supplies the superior and descending parts of the duodenum?
Branches of the superior pancreaticoduodenal and supra duodenal artery
214
What artery supplies the horizontal and ascending parts of the duodenum?
Branches of the inferior pancreaticoduodenal arteries
215
In what quadrant is the jejunum mostly found?
Upper left quadrant
216
In what quadrant is the ileum mostly found?
lower right quadrant
217
Where does the ileum end?
At the ileocaecal valve at the ileocaecal junction
218
What differentiates the ileum and jejunum?
The jejunum contains more, larger place circularis
The jejunum has fewer arterial arcades with longer vasa recta
The ileum contains fewer, if any, lice circularis and contains more arterial arcades with shorter vasa recta
219
What is found running between the ascending and descending colon and the body wall?
Pancolic gutters
220
Which sac of the peritoneal cavity are the paracolic gutters found in?
Greater sac
221
What is the name given to the 3 columns of smooth muscle running along the large colon?
Teniae coli
222
What is the name given to the small fatty streaks that attach to the teniae coli?
Epiploic appendages
223
What is the name given to the physiological in-pouchings of the large colon?
Haustra
224
What 4 factors are required for the control of faecal excretion?
Storage area
Visceral afferent nerve fibres
Functioning muscular sphincters
Normal cerebral function
225
What are some neurological conditions that can affect faecal continence?
Dementia
Stroke
Multiple Sclerosis
Traume (e.g. spinal cord injury, childbirth)
226
What are some non-neurological factors that can affect faecal continence?
Medication
Age
Stool consistency
227
What does the pelvic floor divide?
The pelvic cavity and perineum
228
Is there is physical divide between the pelvic cavity and abdominal cavity?
No
229
What is the name given to the pelvic floor muscle?
Levator ani
230
At what level can the rectosigmoid junction be found?
S3
231
At what levels does the rectum form the anal canal?
Just past the tip of the coxyx
232
Which GI structures are found in the perineum?
Anal canal
Anus
233
What is the rectal ampulla?
A widening of the rectum found just before the anal canal
234
What are the 3 in-pouchings of the rectum called?
Superior rectal valve
Middle rectal valve
Inferior rectal valve
235
What is the difference between the pelvic diaphragm and pelvic floor?
The pelvic diaphragm is the name given to the muscle and fascia of the pelvic floor, which contains other levels
236
What are the 3 smaller muscles that make up the levator ani muscle?
Ruborectalis
Pubococcygeus
Iliococcygeus
237
What type of muscle makes up the levator ani?
Skeletal muscle (voluntary)
238
What affect does increased intra-abdominal pressure have on the levator ani?
It causes increased sympathetic tone, therefore causing contraction of the levator ani
239
What are the 2 main nerves that supply the levator ani?
Nerve to levator ani
Pudendal
240
What spinal nerves make up the pudendal nerve?
Anterior rami of S2, 3 and 4 (S2, 3 and 4 keeps the anus off the floor)
241
Where does the nerve to levator ani originate?
Sacral plexus
242
How does the puborectalis form a sphincter?
243
What forms the anorectal angle?
The anorectal angle is formed by the puborectalis muscle, pulling the anal canal forward from the rectum, towards the pubic symphysis
244
How many anal sphincters are there?
2
245
What are the 2 types of anal sphincter?
Internal anal sphincter
External anal sphincter
246
What type of muscle forms the internal anal sphincter?
Smooth muscle (Involuntary)
247
What type of muscle forms the external anal sphincter?
Skeletal muscle
248
What region of the anal canal is covered by the internal anal sphincter?
Superior 2/3rds
249
hat region of the anal canal is covered by the external anal sphincter?
Inferior 2/3rds
250
What nerve stimulates contraction of the external anal sphincter?
Pudendal nerve
251
What type of nerve innervation stimulates contraction of the internal anal sphincter?
Sympathetic stimulation causes contraction of the internal anal sphincter
252
What type of nerve innervation stimulates relaxation of the internal anal sphincter?
Parasympathetic stimulation causes relaxation of the internal anal sphincter
253
True or false: The parasympathetic innervation can override the sympathetic innervation of the internal anal sphincter
True
254
From what spinal levels does sympathetic innervation to the internal anal sphincter come from?
T12 - L2
255
From what spinal level does parasympathetic innervation to the internal anal sphincter come from?
S2 - S4
256
What is the function of visceral afferent nerves in the rectum?
They detect fullness of the rectum and control opening and closing of the internal anal sphincter
257
Describe the route of the pudendal nerve
Formed by the anterior rami of S2, 3 and 4
Passes out of the greater sciatic foramen
Passes into the perineum and branches to supply the peritoneum
258
How can labour cause faecal incontinence?
Labour can strecth and damage the nerve fibres of the pudendal nerve
Labour and an episiotomy can also damage the muscle itself
259
What is the pectinate line?
This is the division between the viscera and body wall in the anal canal
260
What structures are found just above the pectinate line?
Small anal columns, above anal recesses, and anal glands
261
Describe the nerve innervation of structures above the pectinate line
Autonomic nerve supply
262
Describe the nerve innervation of structures below the pectinate line
Somatic and pudendal nerve supply
263
Where do structure above the pectinate line drain their lymphatics into?
Inferior mesenteric nodes
264
Where do structures below the pectinate line drain their lymphatics into?
Superficial inguinal nodes
265
What are the 3 main groups of lymph nodes within the pelvis?
Internal iliac nodes
External iliac nodes
Common iliac nodes
266
What are the ischioanal fossae?
These are fat and loose tissue flled spaces either side of the anal canal, between which communications run
267
What is an infection of the ischioanal fossae known as?
Ischioanal abscess
268
What is herniation?
The movement of a structure through another, ending up in the wrong place
269
What 2 things are required for herniation?
Structural weakness
Increased pressure
270
Where are some normal weaknesses of the abdominal cavity?
Diaphragm
Umbilicus
Inguinal canal
Femoral canal
Linea semilunaris
Linea alba
271
What are some pathological weaknesses of the abdominal cavity?
Congenital diaphragmatic hernia
Surgical scars/incisional hernia
272
What are some common causes of increased pressure that can lead to herniation?
Chronic cough
Pregnancy
Strenuous exercise
Straining during defecation or urination
273
What is an inguinal hernia?
These are hernias in which the small intestine passes through the inguinal canal
274
What are the 2 types of inguinal hernia?
Direct inguinal hernia
Indirect inguinal hernia
275
What is meant by a direct inguinal hernia?
This occurs when the small intestine is forced through the posterior wall of the inguinal canal and passes out through the superficial ring of the inguinal canal, bringing with it a sac of body wall
276
What is the area through which a direct inguinal hernia will break through the abdominal wall?
Hesselbach's triangle
277
What makes up Hesselbach's triangle?
- Inferior epigastric artery
- Lateral border of rectus abdominus
- Inguinal ligament
278
Direct inguinal hernias will push through .... to the inferior epigastric artery
Medially
279
What is an indirect inguinal hernia?
These occur when the small intstine is forced through the deep ring and into theinguinal canal, before passing back out into the scrotum via the superficial ring
280
Where can the inferior epigastric artery be found?
Half way between the pubic tubercle and anterior superior iliac spine
281
How can the type of inguinal hernia be tested clinically?
- Push hernia back in
- Place thumb over deep ring (Between pubic tubercle and anterior superior iliac spine)
- Ask patient to cough
- Direct hernias will ‘pop’ back out
- Indirect hernias will be stopped by your thumb
282
Where is the sub-inguinal space found?
Beneath the inguinal ligament
283
What is contained in the sub- inguinal space?
Femoral canal, allowing movement of hip flexors, the femoral artery, femoral vein, nerves and lymphatics
284
What is the name given to the space of weakness in femoral hernia?
Myopectineal orifice
285
What is a femoral hernia?
This is the movement of the small intestine through the femoral canal
286
What types of nerves innervate the organs of the GI tract?
Visceral afferent
Sympathetic
Parasympathetic
Enteric
287
What types of nerve innervate the body wall?
Somatic sensory
Somatic motor
Sympathetic
288
Where do sympathetic nerves exit the spinal cord?
T1 - L2
289
Which sympathetic spinal nerves mostly supply the GI tract?
T5 - L2
290
Describe the route of sympathetic action potentials from the spinal cord to the GI tract
Pass into sympathetic trunks
Do not synapse
Form the abdominopelvic splanchnic nerves
Join the pre-vertebral ganglia at the abdominal aorta branches
Travel to organs along the aortic branches
291
What is the periarterial plexus?
This is a plexus of sympathetic, parasympathetic and visceral afferent nerves found on the abdominal aorta
292
Describe the pathway of sympathetic action potentials to the adrenal gland
The sympathetic nerve fires for the adrenal gland leaves the spinal cord (T10-L1), enters the thoracic splanchnic nerves, but does not synapse at the pre-vertebral ganglia, instead it carries on going with the periarterial plexus to the adrenal gland, synapsing directly onto the cells
293
What nerves supply most of the GI tract with parasympathetic innervation?
Vagus nerve
Pelvic splanchnic nerves (S2,3 and 4)
294
What regions of the GI tract are supplied by the vagus nerve?
All GI organs up to the distal end of the transverse colon
295
What regions of the GI tract are supplied by the pelvic splanchnic nerves?
Between the distal end of the transverse colon to the pectinate line
296
What nerves supply the body wall of the abdomen?
Thoracoabdominal nerves
Subcostal nerve
Iliohypogastric nerve
Ilioinguinal nerve
297
Where do the thoracoabdominal nerves arise from?
They are extensions of the intercostal nerves of ribs 7-11 which then move down into the abdomen, travelling between the internal oblique and transversus abdominus muscles
298
Where does the subcostal nerve arise form?
T12 anterior ramus
299
Where does the iliohypogastric nerve arise?
Half of the L1 anterior ramus
300
Where does the ilioinguinal nerve arise?
Half of the L1 anterior ramus
301
Describe the pain referral patterns of the GI organs
302
Where will pain from the foregut organs be felt?
Epigastric region
303
Where will pain from the midgut organs be felt?
Ubilical region
304
Where will pain from the hindgut organs be felt?
Suprapubic region
305
Where do sensory nerve fibres from the foregut enter the spinal cord ?
T6 - T9
306
Where do sensory nerve fibres from the midgut enter the spinal cord?
T8 - T12
307
Where do sensory nerve fibres form the hindgut enter the spinal cord?
T10 - L2
308
Why can pain from the gallbladder be felt in the right shoulder?
If the gallbladder becomes inflamed, it can rub on the diaphragm, stimulation the phrenic nerve, which enters the spinal cord at C3, 4 and 5
309
How does ERCP work?
This involves insertion of an endoscope into the duodenum, which inserts a radiopaque dye into the major duodenal papilla, allowing the biliary tree to be imaged
310
What type of vessel takes up chylomicrons in the gut?
Lacteals, which transport chylomicrons via the lymphatic system to the left venous angle
311
What lymph nodes do the foregut organs drain to?
Coeliac nodes
312
What lymph nodes do the midgut organs drain to?
Superior mesenteric nodes
313
What lymph nodes so the hindgut organs drain to?
INferior mesenteric nodes
314
What nodes do the kidneys, lower limbs and posterior abdominal wall drain to?
Lumbar nodes
