Week 4: Body Cavities

Question 1

What are the main serous membranes in the body and what compartments are they in?

Answer 1

Thoracic cavity:

Pleura around the lungs

Pericardium around the heart

Abdominopelvic cavity:

Peritoneum around organs of the abdomen/pelvis

Question 2

What are the main aspects of the thoracic cavity, including all parts of the more complicated one?

Answer 2

Two main components: mediastinum (everything except lungs) and pleural cavities (lungs in serous membranes)

Mediastinum is made up of:

Superior mediastinum: above the imaginary axial plane that begins at the sternal angle

Inferior mediastinum: includes the anterior, middle and posterior mediastinum

Question 3

What does the plane intersecting the sternal angle contain?

Answer 3

Aortic arch, bifurcation of trachea, TIV/TV vertebral level, left pulmonary artery

Question 4

What separates the abdominopelvic and thoracic cavities?

Answer 4

The diaphragm

Question 5

What is the “imaginary plane” that separates the abdominal and pelvic cavities?

Answer 5

The pelvic inlet

Question 6

According to their coverage with visceral peritoneum, what are the two classifications of abdominal organs?

Answer 6

Intraperitoneal organs are completely covered by visceral peritoneum (held in place by mesentery, a double layer of folded peritoneum)

Retroperitoneal organs are positioned behind the peritoneum and abdominal wall (aorta, generally in a more fixed position)

Question 7

What structures are retroperitoneal?

Answer 7

Urinary system (kidney, ureter, bladder) + adrenal glands

Aorta and IVC

Part of the rectum

Most of the pancreas

Most of the duodenum

Ascending and descending colon

Question 8

What are the organs commonly found in the digestive tract?

Answer 8

Abdominal esophagus

Stomach

Small intestine (duodenum, jejunum, ileum)

Large intestine (cecum, colon)

Rectum and anal canal

Question 9

What are the accessory digestive organs?

Answer 9

The liver, gall bladder and pancreas

Question 10

What is the biliary tree, what is it’s function and what astructures are involved?

Answer 10

The biliary tree is a network of ducts that connects the liver, gallbladder and duodenum

The biliary tree moves bile from the tree and pancreas to the duodenum at the major duodenal papilla.

Question 11

What sympathetic nerves innervate the fore, mid and hindgut?

Answer 11

Foregut + midgut: thoracic splanchnics

Hindgut: lumbar splanchnics

Question 12

What parasympathetic nerves innervate the fore, mid and hindgut?

Answer 12

Foregut + midgut: Vagus (CN X)

Hindgut: Pelvic splanchnics

Question 13

What divides the fore and midgut?

Answer 13

The duodenal papilla (outlet for common bile duct) is the cutoff for the foregut and midgut

Question 14

What are the organs of the foregut, midgut and hindgut?

Answer 14

Foregut:

Abdominal esophagus, stomach, proximal duodenum up to duodenal papilla, liver, spleen and gallbladder

Midgut:

Duodenum distal to duodenal papilla, ileum, jejunum, ascending colon, and 2/3 of transverse colon

Foregut:

Distal 1/3 of transverse colon, descending colon to superior rectum

Question 15

What are the splanchnic nerves, what do they supply and are they parasymp or symp?

Answer 15

Thoracic splanchnics: sympathetic nerves to foregut/midgut

Lumbar splanchnics: sympathetic nerves to hindgut

Sacral splanchnics: sympathetic nerves to pelvic organs/genitals

Pelvic splanchnics: parasympathetic to pelvic organs/genitals

Question 16

How would a nerve travel to a foregut organ?

Answer 16

Through a greater/thoracic splanchnic nerve to synapse at the the celiac ganglion (superior mesentery for midgut, inferior mesentery for hindgut), then through a postganglionic sympathetic nerve to the nearby enteric nerve within the wall of the organ

Question 17

What are the main pelvic contents of females?

Answer 17

Urinary: bladder and urethra

Reproductive: uterus/cervix, ovaries, fallopian tubes, vaginal canal

Digestive: rectum, anal canal

Question 18

What are the main pelvic contents of males?

Answer 18

Urinary: Bladder, ureter, urethra

Reproductive: Vas deferens, seminal vesicles, prostate, urethra, Cowper’s gland

Digestive: Rectum, anus

Outside pelvic cavity: testes, epididymis

Question 19

How is the pelvis innervated?

Answer 19

Sympathetic: lumbar/sacral splanchnics for involuntary control of smooth muscle/glands in perineum and pelvis

Parasympathetic: pelvic splanchnics carry signals to oppose sympathetic regulation of pelvic organs

Question 20

What is the pelvic floor? What is another term for it?

Answer 20

The pelvic floor or pelvic diaphragm that separates pelvic cavity from the perineum and covers the pelvic outlet

It includes the Kegel muscles, and supports pelvic organs, supports the anal and urinary sphincters

The perineum is a diamond-shaped area inferior to the pelvic floor, and contains muscles, glands, erectile tissue and external genitalia

Question 21

What happens with injury of the pelvic floor?

Answer 21

This can cause pelvic organ prolapse (or urinary/rectal incontinence), which can be prevented with a doughnut pessary that helps maintain the integrity of the pelvic floor