GIT-Large Intestine, Large Vessels

Question 1

What do patients with appendicitis usually presents with?

Answer 1

Central abdominal (umbilical) pain followed by pain in the right iliac fossa (right groin or right inguinal region)

Question 2

Large Intestine:
- Extends from the ____ end of the ileum to ____
- Caecum > ____ > ascending > ____ > descending > ____ > ____ > anal canal
- Omental appendices (fatty tags), ____, Haustra are main features
- ____ valve: Folds of mucosa - It’s not effective
- Physiological sphincter at terminal ileum

Answer 2

Large Intestine:
- Extends from the distal end of the ileum to anal canal
- Caecum > appendix > ascending > transverse > descending > sigmoid > rectum > anal canal
- Omental appendices (fatty tags), Teniae coli, Haustra are main features
- Iliocecaecal valve: Folds of mucosa - It’s not effective
- Physiological sphincter at terminal ileum

Question 3

What is the first part of the large intestine?

Answer 3

Cecum

Question 4

Cecum:
- ____ to the ileocecal opening and in the right ____
- Has no ____
- Has ____ bands of _____

Answer 4

Cecum:
- Inferior to the ileocecal opening and in the right iliac fossa
- Has no mesentery
- Has **3 ** bands of teniae coli

Question 5

Appendix:
- Arises from the ____
- Appendix is attached ____ to the ____
- The base of the appendix can be located near the ____ of the ____ at the ____ of the cecum
- Appendix has a short mesentry (mesoappendix)

Answer 5

Appendix:
- Arises from the midgut
- Appendix is attached **posteromedially ** to the cecum
- The base of the appendix can be located near the convergence of the taeniae coli at the tip of the cecum
- Appendix has a short mesentry (mesoappendix)

Question 6

Innervation of the appendix:
It is innervated by the sensory (pain) fibres which accompany the ____ nerve fibres and reach the ____ spinal sensory ganglia

When there is an ____. Initially, the ____ pain perceived in the ____ region as the visceral sensory (pain) fibres which accompany the ____ nerve fibres and reach the ____ spinal sensory ganglia. ____ also innervates the skin around the ____. So, this is how the brain feels pain in an area that is not where the exact pathology is

Visceral pain from appendix is referred to ____ dermatome

Answer 6

Innervation of the appendix:
It is innervated by the sensory (pain) fibres which accompany thesympatheticnerve fibres and reach the T10 spinal sensory ganglia

When there is an appendicitis. Initially, the diffuse pain perceived in the umbilical region as the visceral sensory (pain) fibres which accompany the sympathetic nerve fibres and reach the T10 spinal sensory ganglia. T10 also innervates the skin around the umbilicus. So, this is how the brain feels pain in an area that is not where the exact pathology is.

Visceral pain from appendix is referred to T10 dermatome

Question 7

Innervation of the appendix:
Appendicitis results in swelling, when the swelling touches the ____ peritoneum, then ____ spinal nerve gets irritated, which is ____ sensory which supply the skin to the ____. So, patient feel a sharp pain in the right ____ region in addition to the pain in the ____ region. Thus, sharp prain perceived in the ____ quadrant.

Answer 7

Innervation of the appendix:
Appendicitis results in swelling, when the swelling touches the **parietal **peritoneum, then L1 spinal nerve gets irritated, which is somatic sensory which supply the skin to the inguinal. So, patient feel a sharp pain in the right inguinal region in addition to the pain in the umbilical region. Thus, sharp prain perceived in the right lower quadrant.

Visceral sensory pain felt at T10 spinal sensory ganglia (umbilical region)

Question 8

Briefly describe the pain felt from appendicitis (early and late stage)?

Answer 8

Umbilical pain (visceral) may be present early in the course of the disease is replace with right lower quadrant (somatic) pain later in the illness when the parietal peritoneum becomes involed with the inflammatory process.

Question 9

Ascending colon:
- Lies in the ____
- Forms right ____
- Supplied by right ____ branches of superior mesentric artery
- Innervated by ____ and sympathetic

Answer 9

Ascending colon:
- Lies in the right lower quadrant
- Forms right colic flexure
- Supplied by right colic branches of superior mesentric artery
- Innervated by vagus and sympathetic

Question 10

Transverse colon:
- Occupies the ____ region
- Extends from ____ to ____ colic flexures
- Suspended by the ____
- Supplied by ____ artery (from SMA) and ____ artery (from IMA)

Answer 10

Transverse colon:
- Occupies the umbilical region
- Extends from right to **left **colic flexures
- Suspended by the transverse mesocolon
- Supplied by middle colic artery (from SMA) and left colic artery (from IMA)

Question 11

Innervation of transverse colon:
Proximal 2/3: Parasympathetic ____ and sympathetic

Distal 1/3: Parasympathetic ____ and sypathetic

Answer 11

Innervation of transverse colon:
Proximal 2/3: Parasympathetic vagus and sympathetic

Distal 1/3: Parasympathetic pelvic splanchnic and sypathetic

Question 12

Descending colon:
- Retroperitoneal
- Begins at ____ flexure to end at the ____
- Supplied by ____ branches of ____
- Parasympathetuc innervation by ____ nerve

Answer 12

Descending colon:
- Retroperitoneal
- Begins at splenic flexure to end at the pelvic brim
- Supplied by left colic branches of inferior mesentric artery
- Parasympathetuc innervation by pelvic splanchnic nerve

Question 13

Sigmoid colon:
* Links the ____ colon with ____
* Suspended by a mesentry (____)
* Supplied by the ____ branches of ____
* Innervated by the ____ part of the ____ trunk and pelvic parasympathetic (Inferior hypogastric pleuxus)

Answer 13

Sigmoid colon:
* Links the descending colon with rectum
* Suspended by a mesentry (sigmoid mesocolon)
* Supplied by the sigmoid branches of inferior mesentric artery
* Innervated by the lumbar part of the sympathetic trunk and pelvic parasympathetic (Inferior hypogastric pleuxus)

Question 14

What are the 3 unpaired arteries arising from the anterior of the abdominal aorta?

Answer 14

Coeliac trunk: Foregut + liver, pancreas and spleen
Superior mesentric artery: Midgut
Inferior mesentric artery: Hindgut

Question 15

What are the branches of the superior mesentric artery?

Answer 15

• Jejunal arteries
• Ileal arteries
• Ileocolic artery
• Right colic artery
• Middle colic artery

There is an arterial anastomosis btwn the right colic and middle colic arteries

Question 16

What are the branches of the inferior mesentric artery?

Answer 16

The junction of the mid and hidgut is near the left (splenic) flexure of the colon.

There is a change from superior to inferior mesentric artery supply at this level, but with anastomoses btwn them

Left colic artery, suprior rectal artery and sigmoid arteries

Question 17

Lymphatics:
- The lymphatic drainage of the bowel follows the ____ supply, not the ____ drainage
- The lymph nodes are grouped around the ____
- All lymph drains into the ____
- ____ is an elongated lymphatic sac located in front of the ____ bodies
- The ____ commences from the _____

Answer 17

Lymphatics:
- The lymphatic drainage of the bowel follows the arterial supply, not the venous drainage
- The lymph nodes are grouped around the abdominal aorta
- All lymph drains into the cisterna chyli
- Cisterna chyli is an elongated lymphatic sac located in front of the L1 & L2 bodies
- The thoracic duct commences from the cisterna chyli

Question 18

Innervation of the gut:
- Abdominal viscera supplied by autonomic nervous system
- Sensory fibres most important
- ____ sensory (mediate pain):
- Thoracic splanchnic (____)
- ____ (L1 + L2)
- Parasympathetic sensory (regulate reflex gut function):
- Vagus nerve
- ____ nerves(S2-S4)

Answer 18

Innervation of the gut:
- Abdominal viscera supplied by autonomic nervous system
- Sensory fibres most important
- Sympathetic sensory (mediate pain):
- Thoracic splanchnic (T5-T12)
- **Lumbar splanchnic **(L1 + L2)
- Parasympathetic sensory (regulate reflex gut function):
- Vagus nerve
- Pelvic splanchnic nerves(S2-S4)

Question 19

What can the thoracic splanchnic nerve be further divided to?

Answer 19

Thoracic splanchnic nerve (T5 to 12)
* Greater splanchnic (T5-T9)
* Lesser splanchnic (T10 - T11)
* Least splanchnic (T12)

Question 20

Which vertebra level does the rectosigmoid junction lies?

Answer 20

S3

Question 21

Rectum:
- It follows the curve of the ____ and ____, forming the ____ flexure of the rectum
- It ends anteroinferior to the ____ of the coccyx where it turns ____ and becomes the ____
- The dilated terminal part, the ____ of the rectum, supports and retains the ____ mass before its expelled during ____
- Its terminal part bends sharply in a ____ direction, ____ flexure, as it perforates the ____ diaohragm to become the _____

Answer 21

Rectum:
- It follows the curve of the sacrum and coccyx, forming the sacral flexure of the rectum
- It ends anteroinferior to the tip of the coccyx where it turns posteroinferiorly and becomes the anal canal
- The dilated terminal part, the ampulla of the rectum, supports and retains the faecal mass before its expelled during daefacation
- Its terminal part bends sharply in a posterior direction, anorectal flexure, as it perforates the pelvic diaohragm to become the anal canal

Question 22

The roughly ____ anorectal flexure (angle) is an important mechanism for fecal continence and is maintained during the ____ state by the tonus of the ____ muscle and by its active contraction during peristaltic contractions if defecation is not to occur. The relation of ____ during defecation results in ____ of the anorectal junction.

Three sharp lateral flexures of the rectum (superior ____ and inferior) are apparent when the rectum is viewed ____. The flexures are formed in relation to three infoldings (transverse rectal folds): two on the left and one on the right.

Answer 22

The roughly 80° anorectal flexure (angle) is an important mechanism for fecal continence and is maintained during the resting state by the tonus of the puborectalis muscle and by its active contraction during peristaltic contractions if defecation is not to occur. The relation of puborectalis during defecation results in straightening of the anorectal junction.

Three sharp lateral flexures of the rectum (superior, intermediate and inferior) are apparent when the rectum is viewed anteriorly. The flexures are formed in relation to three infoldings (transverse rectal folds): two on the left and one on the right.

Question 23

IMPTTTT
* Peritoneum covers the ____ and ____ surfaces of the ____ third of the rectum, only the anterior surface of the ____ third and ____ surface of the ____ third because its ____
* In females, the pritoneum reflects from the rectum to the ____, where it forms the ____ pouch, from the urinary bladder to the ____, where it forms ____ pouch
* Both pouches are female pelvic recesses

Answer 23

• Peritoneum covers the anterior and lateral surfaces of the superior third of the rectum, only the anterior surface of the middle third and no surface of the inferior third because its subperitoneal
• In females, the pritoneum reflects from the rectum to the uterus where it forms the rectouterine pouch, from the urinary bladder to the uterus, where it forms vesicouterine pouch
• Both pouches are female pelvic recesses

Question 24

Rectum:
- In males, the peritoneum reflects from the ____ to the posterior wall of the bladder, where it forms the floor of the ____ pouch
- In both sezes, lateral reflctions of peritoneum from the superior/upper third of the ____ form ____ space, which permit the rectum to distend as it fills with feces.

Answer 24

• In males, the peritoneum reflects from the rectum to the posterior wall of the bladder, where it forms the floor of the rectovesical pouch
• In both sezes, lateral reflctions of peritoneum from the superior/upper third of the rectum form pararectal space, which permit the rectum to distend as it fills with feces.

Question 25

Arterial supply of the rectum: - The ____ artery is the continuation of the inferior mesentric artery, supplies the proximal part of the rectum - The ____ and ____ middle rectal arteries, usually arising from the inferior vesical (male) or uterine (female) arteries, supply the ____ and ____ parts of the rectum - The ____ rectal arteries, arising from the ____ arteries, supply the anorectal. junction and anal canal

Answer 25

Arterial supply of the rectum: - The **superior rectal artery** is the continuation of the inferior mesentric artery, supplies the proximal part of the rectum - The **right** and **left** middle rectal arteries, usually arising from the inferior vesical (male) or uterine (female) arteries, supply the **middle** and **inferior** parts of the rectum - The **inferior** rectal arteries, arising from the **internal pudenda**l arteries, supply the anorectal. junction and anal canal

Question 26

Venous drainage of the rectum: - The venous drainage of the rectum follows the arteries bearing the same name - The ____ rectal vein empties into the ____ mesentrice vein and then drain into the ____ system - The ____ and ____ rectal veins empty into the internal iliac vein and the ____ (systemic system)

Answer 26

Venous drainage of the rectum: - The venous drainage of the rectum follows the arteries bearing the same name - The **superior** rectal vein empties into the **inferior** mesentric vein and then drain into the **portal** system - The **middle** and **inferior** rectal veins empty into the internal iliac vein and the **inferior vena cava** (systemic system) ## Footnote Because the superior rectal vein drains into the portal venous system and the middle and inferior rectal veins drain into the systemic system, this communication is an important area of portocaval anastomosis

Question 27

Lymphatic rectum: - Lymphatic vessels from the ____ half of the rectum drain into the ____ lymph nodes, located on the ____ layer of the rectum, and then ascend to the ____ lymph nodes - Lymphatic vessels from the ____ half of the rectum drain into the ____ lymph nodes or especially from the ____ ampulla, follow the middle rectal vessels to drain into the ____ lymph nodes.

Answer 27

Lymphatic vessels from the **superior** half of the rectum drain into the **pararectal** lymph nodes, located on the **muscle** layer of the rectum, and then ascend to the **inferior mesentric** lymph nodes - Lymphatic vessels from the **inferior** half of the rectum drain into the **sacral** lymph nodes or especially from the **distal** ampulla, follow the middle rectal vessels to drain into the **internal iliac** lymph nodes. ## Footnote Key prognostic factor for rectal cancer is the involvement of lymph nodes

Question 28

Nerve supply of the rectum: - From sympathetic and parasympathetic nervous system - ____ supply is from the lumbar spinal cord, conveyed via the ____ nerves (L1-L2) - ____ supply is from the sacral spinal cord, passing via the ____ nerves (S2-S4) - The rectum above the pelvic pain line, visceral afferent fibers follow the ____ fibers to the L1-L2 spinal sensory ganglia - The rectum below the pelvic pain line, visceral afferent fibers follow the parasympathetic fibers retrogradely to the ____ spinal sensory ganglia

Answer 28

Nerve supply of the rectum: - From sympathetic and parasympathetic nervous system -**Sympathetic** supply is from the lumbar spinal cord, conveyed via the **lumbar splanchnic** nerves (L1-L2) - **Parasympathetic** supply is from the sacral spinal cord, passing via the **pelvic splanchnic** nerves (S2-S4) - The rectum above the pelvic pain line, visceral afferent fibers follow the **sympathetic** fibers to the L1-L2 spinal sensory ganglia - The rectum below the pelvic pain line, visceral afferent fibers follow the parasympathetic fibers retrogradely to the **S2-S4** spinal sensory gangli

Question 29

Anal canal: - The anal canal is the ____ part of the ____ that extend from the ____ aspect of the ____ to the ____ - The canal begins where the rectal ampulla abruptly ____ at the level of the ____ formed by the puborectalis muscle - The canal ends at the ____, the external outlet of the alimentary tract - The canal, surrounded by ____ and ____ anal ____

Answer 29

Anal canal: - The anal canal is the **terminal** part of the **large intestine** that extend from the **superior** aspect of the **pelvic diaphragm** to the **anus** - The canal begins where the rectal ampulla abruptly **narrows** at the level of the **U-shaped sling** formed by the puborectalis muscle - The canal ends at the **anus**, the external outlet of the alimentary tract - The canal, surrounded by **internal** and **external** anal **sphincters**

Question 30

- The anal canal is normally ____ except during passage of feces. Both sphincter must ____ before defecation can occur. - The ____ anal sphincter is a large ____ sphincter that forms a broad band on each side of the ____ two thirds of the canal. This sphincter blends superiorly with the ____ muscle and is having subcutaneous, superficial and deep parts. - The external anal sphincter is innervated mainly by ____ through the ____ rectal nerve

Answer 30

- The anal canal is normally **collapsed** except during passage of feces. Both sphincter must **relax** before defecation can occur. - The **external** anal sphincter is a large **voluntary** sphincter that forms a broad band on each side of the **inferior** two thirds of the canal. This sphincter blends superiorly with the **puborectalis** muscle and is having subcutaneous, superficial and deep parts. - The external anal sphincter is innervated mainly by **S4** through the **inferior** rectal nerve

Question 31

* The ____ half of the ____ of the anal canal is characterized by a series of ____ ridges called anal ____. These columns contain the terminal branches of the superior rectal artery and vein * The anorectal junction/line, indicated by the ____ ends of the anal columns are joined by anal ____ * Superior to the ____ are small recesses called ____. When compressed by feces, the ____ exude mucus that aids in evacuation of feces from the anal canal.

Answer 31

* The **superior** half of the **mucus membrane** of the anal canal is characterized by a series of **longitudinal** ridges called **anal columns**. These columns contain the terminal branches of the superior rectal artery and vein * The anorectal junction/line, indicated by the **superior** ends of the anal columns are joined by **anal valves** * Superior to the **anal valves** are small recesses called **anal sinuses**. When compressed by feces, the **anal sinuses** exude mucus that aids in evacuation of feces from the anal canal.

Question 32

Anal canal: - The inferior ____ limit of the anal valves forms an irregular line, the ____ line which indicates the junction of the ____ part of the anal canal (visceral, derived from the hindgut) and the inferior part (somatic, derived from the embryonic proctodeum) - The anal canal superior to the pectinate line differs from the part inferior to the pectinate line in its ____ supply, innervation and ____ and lymphatic drainage. These differences result fro, their different embryologic origins.

Answer 32

Anal canal: - The inferior **comb-shaped** limit of the anal valves forms an irregular line, the **pectinate** line which indicates the junction of the **superior** part of the anal canal (visceral, derived from the hindgut) and the inferior part (somatic, derived from the embryonic proctodeum) - The anal canal superior to the pectinate line differs from the part inferior to the pectinate line in its **arterial** supply, innervation and v**enous** and lymphatic drainage. These differences result fro, their different embryologic origins.

Question 33

Anal canal: - The ____ artery supplies the anal canal ____ to the pectinate line. The two ____ arteries supply the inferior part of the anal canal as well as the surrounding muscles and perianal skin. - The ____ artery assist with the blood supply to the anal canal by forming ____ with the superior and inferior rectal arteries

Answer 33

- The **superior rectal** artery supplies the anal canal **superior** to the pectinate line. The two **inferior rectal** arteries supply the inferior part of the anal canal as well as the surrounding muscles and perianal skin. - The **middle rectal** artery assist with the blood supply to the anal canal by forming **anastomoses** with the superior and inferior rectal arteries

Question 34

Anal canal: - The ____ rectal venous plexus drains in both directions from the level of the ____ - ____ to the pectinate line, the internal ____ drains mainly into the inferior rectal vein (tributaries of the internal ____ veins) and the ____ venous system around the margin of the external anal sphincter - The ____ rectal veins (tributaries of the internal iliac veins) mainly drain the muscularis externa of the rectal ampulla and form ____ with the ____ and ____ rectal veins

Answer 34

- The **internal** rectal venous plexus drains in both directions from the level of the **pectinate line** - **Superior** to the pectinate line, the **internal rectal venous plexus** drains mainly into the inferior rectal vein (tributaries of the internal **pudendal** veins) and the **caval** venous system around the margin of the external anal sphincter - The **middle** rectal veins (tributaries of the internal iliac veins) mainly drain the muscularis externa of the rectal ampulla and form **anastomoses** with the **superior** and **inferior** rectal veins

Question 35

What is external hemorrhoids and what are some predisposing factors?

Answer 35

External hemorrhoids are thromboses (blood clots) in the veins of the ____ rectal venous plexus and are covered by ____ Predisposing factors: - Pregnancy - Chronic constipation - Disorder that impededs venous return, including increased intra-abdominal pressure

Question 36

What is another name for internal hemorrhoids?

Answer 36

Piles

Question 37

What are internal hemorrhoids?

Answer 37

Prolapses of the rectal mucosa containing the normally dilated veins of the internal rectal venous plexus. They are result from a breakdown of the muscularis mucosae, a smooth muscle layer deep to the mucosa Internal hemorrhoids that prolapse through the anal canal are often compressed by the contracted sphincters, impeding blood flow. As a result, they tend to strangulate and ulcerate. Owing to the presence of abundant arteriovenous anastomoses, bleeding from internal hemprrhoids is usally brigh red

Question 38

IMPTTTT Portal Systemic Anastomoses: The anastomoses among the superior, middle and inferior rectal veins form clinically important communications between the ____ and the ____ venous systems The ____ rectal vein drains into the ____ vein (portal system), wheras the ____ and ____ drain into the ____ and ____ veins through the inferior vena cava (systemic system) Any abnormal increase in ____ in the ____ portal system or veins of the trunk may cause ____ of the superior rectal veins, resulting in increase in blood flow or stasis in the internal rectal venous plexus In portal hypertension, as in hepatic cirrhosis, the ____ anastomosis among the superior, middle, and inferior rectal veins, along with portocaval anastomoses elsewhere, may become ____ It is important to note that the veins of the rectal plexus appear ____ (dilated and tortuous) and that the internal hemorrhoids occur most commonly in the absence of portal hypertension

Answer 38

The anastomoses among the superior, middle and inferior rectal veins form clinically important communications between the **portal** and the **systemic** venous systems The **superior** rectal vein drains into the **inferior mesentric** vein (portal system), wheras the **middle** and **inferior rectal** drain into the **internal iliac** and **internal pudendal** veins through the inferior vena cava (systemic system) Any abnormal increase in **pressure** in the **valveless** portal system or veins of the trunk may cause **enlargement** of the superior rectal veins, resulting in increase in blood flow or stasis in the internal rectal venous plexus In portal hypertension, as in hepatic cirrhosis, the **portocaval** anastomosis among the superior, middle, and inferior rectal veins, along with portocaval anastomoses elsewhere, may become **varicose** It is important to note that the veins of the rectal plexus appear **varicose** (dilated and tortuous) and that the internal hemorrhoids occur most commonly in the absence of portal hypertension

Question 39

Superior to the pectinate line: The lymphatic vessels drain into the ____ lymph nodes and through them into the ____ and ____ lymph nodes Inferior to the pectinate line: The lymphatic vessels drain into the ____ lymph nodes

Answer 39

Superior to the pectinate line: The lymphatic vessels drain into the **internal iliac** lymph nodes and through them into the **common iliac** and **lumbar** lymph nodes Inferior to the pectinate line: The lymphatic vessels drain into the **superficial inguinal** lymph nodes

Question 40

Nerve supply: Because visceral afferent nerves supply the anal canal ____ to the pectinate line, and incision or a needle insertion in this region is ____ However, the anal canal ____ to the pectinate line is quite sensitive (e.g. to the prick of a hypodermic needle) because it is supplied by the ____ rectal nerves, containing ____ sensory fibers.

Answer 40

Nerve supply: Because visceral afferent nerves supply the anal canal **superior** to the pectinate line, and incision or a needle insertion in this region is **painless** However, the anal canal **inferior** to the pectinate line is quite sensitive (e.g. to the prick of a hypodermic needle) because it is supplied by the i**nferior** rectal nerves, containing **somatic** sensory fibers.

Question 41

What is a common and cost-effective treatment for internal hemorrhoids?

Answer 41

Rubber band ligation ## Footnote Pain after rubber band ligation is the most common complication

Question 42

Nerve supply: - The internal anal sphincter is an ____ sphincter surrounding the superior two thirds of the anal canal - It's a ____ of the circular muscle layer - Its contraction (tonus) is stimulated and maintained by the ____ fibers - It's inhibited (loses its tonic contraction and is allowed to expand passively) by the ____ fibers - This sphincter is tonically contracted most of the time to prevent ____ of fluid or flatus. However, it relaxes temporarily in response to distension of the rectal ampulla by faeces or gas, requiring voluntary contraction of the puborectalis and the external anal spincter if defecation or flatulence is not to occur

Answer 42

- The internal anal sphincter is an **involuntary** sphincter surrounding the superior two thirds of the anal canal - It's a **thickening** of the circular muscle layer - Its contraction (tonus) is stimulated and maintained by the **sympathetic** fibers - It's inhibited (loses its tonic contraction and is allowed to expand passively) by the **parasympathetic** fibers - This sphincter is tonically contracted most of the time to prevent **leakage** of fluid or flatus. However, it relaxes temporarily in response to distension of the rectal ampulla by faeces or gas, requiring voluntary contraction of the puborectalis and the external anal spincter if defecation or flatulence is not to occur

Question 43

Nerve supply: - The nerve supply of the anal canal ____ to the pectinate line is ____ innervation from sympathetic, parasympathetic and visceral afferent fibers. Therefore, this part of the anal canal is ____ only to ____ - The nerve supply of the anal canal ____ to the pectinate line is ____ innervation from the inferior anal (rectal) nerves, branches of the pudendal nerve. Therefore, this part of the anal canal is ____ to pain, touch and ____. - Somatic efferent fibers stimulate the ____ of the voluntary external anal sphincter

Answer 43

Nerve supply: - The nerve supply of the anal canal **superior** to the pectinate line is **visceral** innervation from sympathetic, parasympathetic and visceral afferent fibers. Therefore, this part of the anal canal is **sensitive** only to **stretching** - The nerve supply of the anal canal i**nferior** to the pectinate line is **somatic** innervation from the inferior anal (rectal) nerves, branches of the pudendal nerve. Therefore, this part of the anal canal is **sensitive** to pain, touch and **temperature.** - Somatic efferent fibers stimulate the **contraction** of the voluntary external anal sphincter

Question 44

Whats a barium enema?

Answer 44

A barium enema is an X-ray exam that can detect changes or abnormalities in the large intestine (colon). ## Footnote Also called a colonn X-Ray

Question 45

What abnormalities does a colonoscopy detect?

Answer 45

Detect changes or abnormalities in the large intestine (up to cecum) and rectum ## Footnote Inseted into the rectum

Question 46

Abdominal aorta: * Begins at the aortic ____ in the diaphragm at T12 and ends by dividing into the right and left ____ arteries at L4 * Common ____ artery divides into external and internal ____ arteries * On its right side lie the ____, cisterna chyli and ____ vein * On its left side lies the ____ trunk

Answer 46

Abdominal aorta: * Begins at the aortic **hiatus** in the diaphragm at T12 and ends by dividing into the right and left **common iliac arteries** at L4 * Common **iliac** artery divides into external and internal **iliac** arteries * On its right side lie the **IVC**, cisterna chyli and **azygous** vein * On its left side lies the **left sympathetic** trunk

Question 47

IVC: - Returns blood from all structures below the ____ to the right atrium of the heart - Formed by the union of common ____ veins at ____ - Ascends through the ____ abdominal wall on the ____ side of the ____, passes through the ____ (T8) and drains into the right atrium

Answer 47

IVC: - Returns blood from all structures below the **diaphragm** to the right atrium of the heart - Formed by the union of common **iliac** veins at **L5** - Ascends through the **posterior** abdominal wall on the **right** side of the **aorta**, passes through the **caval foramen (T8)** and drains into the right atrium

Question 48

Somatic and autonomic nerves: Subcostal: Iliohypogastric: Ilioinguinal: Lateral femoral cutaneous: Genitofemoral: Femoral: Lumbar sympathetic trunk

Answer 48

Somatic and autonomic nerves: Subcostal: T12 Iliohypogastric: L1 Ilioinguinal: L1 Lateral femoral cutaneous: L2, L3 Genitofemoral: L1, L2 Femoral: L2-L4 Lumbar sympathetic trunk

Question 49

Somatic & Autonomic Nerves: T12: L1: L1: L2, L3: L1, L2: L2 - L4: Lumbar sympathetic trunk

Answer 49

Somatic and autonomic nerves: T12 Subcostal: L1 Iliohypogastric: L1 Ilioinguinal: Lateral femoral cutaneous: L2, L3 Genitofemoral: L1, L2 Femoral: L2-L4 Lumbar sympathetic trunk (Add Clarifier)

Question 50

Name the four aortic plexus

Answer 50

Celiac plexus Superior mesenteric plexus Inferior mesenteric plexus Renal plexus Components: * Pre and post ganglionic sympathetic fibres * Visceral sensory * Pre-ganglionic parasympathetic fibres