Abdominal Wall and Organs

Functions of Abdominal Wall Musculature

Protect the abdominal viscera from injury • Adjust intra-abdominal pressure and assist in expiration • Move the trunk and help to maintain posture.

Pelvis: Osteology

he pelvis develops from the fusion of three
bones, the ilium, ischium, and pubis

the ilium

ischium

pubis

Iliac Crest

Pubic Tubercle

Anterior superior iliac spine

anterior inferior iliac spine

External oblique and Internal oblique

The flat muscles of the
anterolateral abdominal
wall include

linea alba

The aponeuroses of
these muscles interlace
at the

External Oblique (EO) Muscle Action

Bilateral contraction – Flexes trunk – Compresses abdominal viscera

Unilateral contraction – rotates trunk to the contralateral (opposite) side

inguinal ligament

the lower border of the external oblique aponeurosis folds
and forms the —— on each side

Inguinal Ligament Passes between

the ASIS and the pubic tubercle

Internal Oblique (IO) Muscle Action

Bilateral contraction – Flexes trunk – Compresses abdominal viscera

Unilateral contraction – rotates trunk to the ipsilateral (same) side

Rectus Abdominis Action

Compresses, supports abdominal viscera, flexes trunk

Abdominal Cavity

Peritoneum

a continuous, bilayered membrane—lines the abdominopelvic cavity and surrounds the viscera (organs)

Parietal peritoneum

lining the internal surface of the abdominopelvic wall

Visceral peritoneum

investing the viscera such as the stomach and intestines

Digestive System - Gastrointestinal Tract

Esophagus • Stomach • Small intestine • Large intestine

Organs of digestion

Liver • Gall bladder • Pancreas

Esophagus

Continuous with the pharynx (back of oral cavity).
• Passes through the esophageal hiatus of the diaphragm, at the level of the T10 vertebra.
• Terminates by entering the stomach at the cardiac region of the stomach.

Stomach Function

Mechanical and chemical digestion

Stomach regions

Cardiac Region • Fundus • Body • Pylorus

Small Intestine HAS

Three regions based on interior lining cells.

Small Intestine - Duodenum FUNCTION

Digestion

Jejunum & Ileum Function

Absorption

Large Intestine Large Intestine (Colon) Regions

Cecum • Ascending colon • Transverse colon • Descending colon • Sigmoid colon

Large Intestine (Colon) Function

absorb water & salts • transmit waste

Appendix

a pouch which extends from the intestine which contains masses of lymphoid (immune) tissue. It arises from the cecum inferior to the ileocecal junction

Liver structure

Two primary lobes

Liver Function

Filters blood from GI tract (removes toxins, starts to break down ingested substances, etc.),

produces bile

Liver Location

The liver lies primarily on the right side protected by the lower ribs

Hepatic Circulation Portal Vein

Carries deoxygenated blood containing absorbed nutrients and potentially harmful substances from the intestines to the liver

Hepatic Vein

Carries processed blood from the liver to the inferior vena cava

Hepatic Artery

Supplies oxygenated blood to the liver tissue.

Gall Bladder Function

Stores & concentrates the bile which was produced by the liver. Releases bile as needed into the duodenum

Gall Bladder Location

Lies on the posterior surface of the liver

Pancreas Function

Produces hormones that regulate metabolism and also produced digestive enzymes. Releases enzymes into the duodenum.

Pancreas Location

in the upper lumbar region near the duodenum of the small intestine

Kidneys Function

filter the blood to remove metabolic waste while maintaining the body's fluid and electrolyte balance

Ureters Function

muscular ducts that carry urine from the kidneys to the urinary bladder

Kidneys + Ureters Location

The superior aspects of the kidneys lie deep to the lower ribs.

suprarenal (adrenal) gland location

between the superior aspects of the kidneys and the diaphragm

Suprarenal (Adrenal) Gland Function

produce hormones that regulate the body's response to stress and help maintain homeostasis

Spleen Function

Largest lymph organ • Filters blood – Digests bacteria and depleted red blood cells

Spleen Location

deep to left lower ribs

normally does not descend inferior to the costal margin

Abdominal Aorta - Unpaired Branches

Celiac trunk • Superior mesenteric artery • Inferior mesenteric artery

Abdominal Aorta - Terminal Branches

Common iliac arteries

Blood Supply to GI Tract Regions - • Foregut:

Esophagus, stomach, duodenum, liver, gall bladder, pancreas, spleen- supplied by the celiac trunk

Blood Supply to GI Tract Regions - midgut

Jejunum, ileum, cecum, ascending and 2/3 transverse colon- supplied by the superior mesenteric artery

Hindgut

1/3 transverse colon, descending colon, sigmoid colon, rectum- supplied by the inferior mesenteric artery

Inferior Vena Cava (IVC) Begins

begins anterior to the L5 vertebra by the union of the common iliac veins.

Inferior Vena Cava (IVC) Leaves the abomin

by passing through the caval opening in the diaphragm to enter the thorax at the T8 vertebral level.

IVC Function

Collects poorly oxygenated blood from the lower limbs and non-portal blood from the abdomen and pelvis.