Mod 3: Lecture 1 - Abdominal Wall and Contents Flashcards Preview

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1

Abdominal Cavity

- 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

2

Anterior Abdominal Wall

- 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

3

Pelvis: Osteology

- 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

4

Landmarks on the Pelvic Bones

- 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

5

External Oblique Muscles
1. Attachments
2. Action
3. Innervation

- 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

6

Internal Oblique Muscles
1. Attachments
2. Action
3. Innervation

- 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

7

Transversus Abdominus (TA) Muscle
1. Attachments
2. Action
3. Innervation

- 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

8

Rectus Abdominus
1. Attachments
2. Action
3. Innervation

- 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

9

Functions of the Abdominal Wall Musculature

- 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

10

Structure of the Inguinal Ligament and Canal

- 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

11

Contents of the Inguinal Canal

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

12

Inguinal Hernia

- 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

13

Peritoneum

- 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

14

Abdominal Organs under the Protection of the Ribs

- 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

15

Abdominal Organs: Digestive System

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

16

Abdominal Organs: Other (Non-Digestive System)

- Kidneys
- Spleen

17

Esophagus: location

- 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

18

Stomach
1. Function
2. Regions

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

19

Pyloric Sphincter

- 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

20

Small Intestine

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

21

Large Intestine

- 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

22

Appendix

- 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

23

Liver: Location

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

24

Liver: Function

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

25

Liver: Structure

- 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

26

Hepatic Circulation

- 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

27

Gall Bladder

- 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

28

Pancreas

- 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

29

Kidneys

- 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

30

Suprarenal (Adrenal) Gland

- 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