Mod 3: Lecture 1 - Abdominal Wall and Contents

Question 1

Abdominal Cavity

Answer 1

• major part of the abdominopelvic cavity
• — continuous inferiorly with the pelvic cavity
• separated from the thoracic cavity by the diaphragm
• — under cover of the thoracic cage superiorly
• the location of most digestive organs, the spleen, and parts of the urogenital system (kidneys and most of the ureters)
• enclosed anterolaterally by multilayered, musculoaponeurotic abdominal walls

Question 2

Anterior Abdominal Wall

Answer 2

• three flat muscles
• — external oblique
• — internal oblique
• — transverse abdominis
• — all anteriorly end in a strong sheetlike aponeurosis
• —- an aponeurosis is similar to a tendon, but is flat instead of cord-like
• —- the aponeuroses of these muscles interlace at the linea alba
• —- linea alba is at the midline of the body
• vertical muscles
• — rectus abdominus

Question 3

Pelvis: Osteology

Answer 3

• develops from the fusion of three bones
• Ilium: big flat upper region
• Ischium: the under and back part of the bottom curve
• Pubis: the center/top part of the bottom curve

Question 4

Landmarks on the Pelvic Bones

Answer 4

• serve as attachments for muscles and ligaments
• all are bilateral
• Iliac Crest: the big curve on the top of the ilium
• ASIS: anterior superior iliac spine
• — the ridge at the front end of the iliac crest
• Anterior Inferior Iliac Spine: below the superior spine, where the bone juts back out after curving in
• Pubic Symphysis: the cartilaginous disc in the middle of the pelvis
• Pubic Tubercle: the little bump on the pubis just to the side of the pubic symphysis

Question 5

External Oblique Muscles

1. Attachments
2. Action
3. Innervation

Answer 5

• orientation of fibers is the angle as if you were putting your hands in your front pockets
  1. - ribs 5-12
• linea alba, pubic tubercle, iliac crest
  2. - compress, support abdominal viscera
• flex and rotate trunk
  3. - segmental thoracoabdominal nerves

Question 6

Internal Oblique Muscles

1. Attachments
2. Action
3. Innervation

Answer 6

• deep to the external obliques
• fiber direction is angled down to the side of the body, opposite direction of the external obliques
  1. - thoracolumbar fascia, iliac crest, inguinal ligament
• ribs 10-12, linea alba
  2. - compress, support abdominal viscera
• flex and rotate trunk
  3. - segmental thoracoabdominal nerves

Question 7

Transversus Abdominus (TA) Muscle

1. Attachments
2. Action
3. Innervation

Answer 7

• fibers are horizontal
  1. - ribs 7-12, costal cartilages, iliac crest, thoracolumbar fascia
• linea alba, pubic crest
  2. - compress, support abdominal viscera
  3. - segmental thoracoabdominal nerves

Question 8

Rectus Abdominus

1. Attachments
2. Action
3. Innervation

Answer 8

• right in the middle of the anterior abdominal wall
  1. - pubic symphysis and pubic crest
• xiphoid process and costal cartilages 5-7
  2. - compress, support abdominal viscera
• flex trunk
• — no rotation bc of vertical orientation
  3. - segmental thoracoabdominal nerves

Question 9

Functions of the Abdominal Wall Musculature

Answer 9

• form a strong expandable support
• protect the abdominal viscera from injury
• compress the abdominal contents
• adjust intra-abdominal pressure and assist in expiration
• move the trunk and help to maintain posture

Question 10

Structure of the Inguinal Ligament and Canal

Answer 10

• the edge of the aponeurosis of the external oblique folds to form the inguinal canal
• —- superficial inguinal ring of tissue around it
• the thickened underturned inferior edge of the aponeurosis of the external oblique forms the inguinal ligament
• — spans between the ASIS and the pubic tubercle

Question 11

Contents of the Inguinal Canal

Answer 11

• Male: spermatic cord
• — ductus deferens
• — testicular artery
• — sympathetic nerve fibers
• Female: round ligament of the uterus
• — helps support the uterus

Question 12

Inguinal Hernia

Answer 12

• when structures that are not supposed to, such as the small intestine, pass through the inguinal canal
• — these organs are too large to fit comfortably

Question 13

Peritoneum

Answer 13

• a continuous, bilayered transparent serous membrane
• lines the abdominopelvic cavity and encloses the viscera
• Parietal Peritoneum: lining the internal surface of the abdominopelvic wall
• — closer to the muscles
• — outer layer
• Visceral Peritoneum: enclosing the viscera, such as the stomach and intestines
• — inner layer

Question 14

Abdominal Organs under the Protection of the Ribs

Answer 14

• the stomach, the liver, and spleen have some protection from the lower ribs
• because the diaphragm is dome shaped
• — the diaphragm curves up, leaving space in the abdominal cavity that is still under the ribs
• the diaphragm, not the ribs, is the border of the thoracic and abdominal cavities

Question 15

Abdominal Organs: Digestive System

Answer 15

• Esophagus
• Stomach
• Small Intestine
• Large Intestine
• Rectum/Anus
• Organs of Digestion
• — Liver
• — Gall Bladder
• — Pancreas

Question 16

Abdominal Organs: Other (Non-Digestive System)

Answer 16

• Kidneys

- Spleen

Question 17

Esophagus: location

Answer 17

• passes through the elliptical esophageal hiatus in the muscular right crus of the diaphragm
• — just to the left of the median plane at the level of the T10 vertebra
• — so most of it is in the thoracic cavity
• terminates by entering the stomach at the cardial orifice of the stomach
• — to the left of the midline at the level of the 7th left costal cartilage and T11 vertebra
• — the inferior portion of it is in the abdominal cavity

Question 18

Stomach

1. Function
2. Regions

Answer 18

1. mechanical and chemical digestion
2. • Cardia: the part that receives the esophagus
     - Fundus the domed part superior at the top, superior to the end of the esophagus
     - Body: the middle, most of the stomach
     - Pyloric Region: where the stomach narrows to taper off, heading into the small intestine
     - — pyloric antrum and then pyloric canal
     - — pyloric sphincter

Question 19

Pyloric Sphincter

Answer 19

• the pylorus is thickened to form the pyloric sphincter
• — pylorus: the distal sphincteric region of the pyloric part of the stomach
• controls discharge of the stomach contents through the pyloric orifice into the duodenum
• — circular muscle which contracts and relaxes

Question 20

Small Intestine

Answer 20

1. Duodenum: digestion
   - — duodenum is first bc you need to digest before you absorb and “d” is for digestion/duodenum
2. Jejunum: absorption
   - — jejunum is second bc june starts the second half of the year
3. Ileum: absorption
   - — ileum is third bc it is closest to the ilium of the pelvis

Question 21

Large Intestine

Answer 21

• absorb water and salts
  1. Cecum
• — ileocecal junction: where the ileum of the small intestine enters the large intestine
• — the pouch that sticks out and precedes the ileocecal junction
  2. Ascending Colon
  3. Transverse Colon
  4. Descending Colon
  5. Sigmoid Colon
• — the area right before the rectum

Question 22

Appendix

Answer 22

• a blind intestinal diverticulum that contains masses of lymphoid tissue
• — a 6-10 cm long pouch
• arises from the posteromedial aspect of the cecum inferior to the ileocecal junction
• — comes off of the end of the cecum
• no specific function related to digestion

Question 23

Liver: Location

Answer 23

• the normal liver lies deep to ribs 7 through 11 on the right side, but does cross somewhat over to the left side

Question 24

Liver: Function

Answer 24

• processing nutrients from the digestive tract
• making bile for digestion
• removing toxins from blood
• producing proteins such as clotting factors

Question 25

Liver: Structure

Answer 25

• 4 Lobes
• — right: biggest
• — left: second biggest
• — quadrate: in the center on the bottom, only visible from posterior side, significantly smaller than right and left lobes,
• — caudate: in the center on the top, only visible from posterior side, smallest lobe
• Porta Hepatis: hole in the liver that lets stuff through
• — point of entry for hepatic arteries and portal vein
• — point of exit for hepatic ducts

Question 26

Hepatic Circulation

Answer 26

• Portal Vein
• — chief vessel of the portal venous system
• — shared pathway for blood from the GI tract back to the heart
• — collects poorly oxygenated but nutrient rich blood from the abdominal part of the GI tract, including the spleen, pancreas, gall bladder
• —- carries the blood back to the liver
• — formed by the union of the splenic and superior mesenteric veins
• — divides into right and left branches before entering the liver
• The liver filters the nutrients out of the blood brought by the portal vein
• Hepatic Vein: carries filtered blood out of the liver to the inferior vena cava
• Hepatic Artery: supplies the parenchyma (tissue) of the liver

Question 27

Gall Bladder

Answer 27

• stores and concentrates bile and releases it to the duodenum
• — duodenum: first part of the small intestine
• on the posterior inferior surface of the liver

Question 28

Pancreas

Answer 28

• Digestive Function: enzyme production
• found in the back of the abdomen, behind the stomach
• — about 6 inches long
• — head of the pancreas is on the right side and is connected to the duodenum

Question 29

Kidneys

Answer 29

• Urinary System
• Function: remove water, salt, etc. from the blood
• Location: the superior poles of the kidneys lie deep to the 11th and 12th ribs
• — right kidney is lower than the left

Question 30

Suprarenal (Adrenal) Gland

Answer 30

• Endocrine system
• located on top of the kidneys
• — at the superior poles
• two regions
• — suprarenal (adrenal) cortex: produces steroid hormones and regulates fluid electrolytes, outer portion
• — suprarenal (adrenal) medulla: produces epinephrine and norepinephrine (“stress hormones”), inner portion

Question 31

Spleen

Answer 31

• located deep to left 9th through 11th ribs
• normally does not descend inferior to the costal region
• largest lymph organ
• — contains B and T lymphocytes
• filters blood
• — digests bacteria and depleted RBC
• receives blood via the large splenic artery

Question 32

Abdominal Blood Supply: Abdominal Aorta - Types of Branches

Answer 32

• Anterior Visceral: GI tract, spleen
• — unpaired
• Lateral Visceral: reproductive organs, kidneys
• — paired
• Posterior Parietal: lumbar, sacral regions
• — paired
• Terminal Branches: hip region and lower extremities
• —- two: the aorta splits

Question 33

Anterior Visceral Branches of the Abdominal Aorta

Answer 33

superior to inferior:

• Celiac Trunk: artery to foregut
• — esophagus, stomach, duodenum, liver, gall bladder, pancreas, spleen
• Superior Mesenteric Artery: to midgut
• — jejunum, ileum, cecum, ascending and 2/3 of transverse colon
• Inferior Mesenteric Artery: to hindgut
• — 1/3 of transverse colon, descending colon, sigmoid colon, rectum

Question 34

Lateral Visceral Branches of the Abdominal Aorta

Answer 34

• All are paired and go to paired organs
• Inferior Phrenic: internal surface of the diaphragm, one to the left side of the abdominal aorta and one to the right
• Suprarenal: adrenal glands
• Renal: kidneys
• Reproductive: ovaries/testes

Question 35

Terminal Branches of the Abdominal Aorta

Answer 35

• At L4/5, the abdominal aorta terminates by dividing into two Common Iliac Arteries
• — each common iliac terminates by dividing into an internal and external iliac
• Internal Iliac (S1): supplies hip and gluteal muscles
• External Iliac (S1): major blood supply for lower extremity
• — becomes the femoral artery after passing under the inguinal ligament